Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
Refine search result
1234567 1 - 50 of 1633
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abali, Bilen Emek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    An Introduction to Piezoelectric and Thermoelectric Materials2022In: Handbook of Energy Materials / [ed] Ram Gupta, Singapore: Springer, 2022, p. 1-18Chapter in book (Refereed)
    Abstract [en]

    Materials may demonstrate electromagnetism and thermomechanics coupling. Although we benefit from this coupling in our modern lives, comprehending this coupling is challenging. We intuitively understand that temperature increase causes an expansion in polymers and alloys. Typical example is a plastic water bottle left in the sun, the expansion is visible by naked eyes. Yet it is more abstract to consider that an electric field may create a deformation or even a temperature change. Electromagnetic fields are more abstract since our senses fail to be sensitive to these physical quantities. There are indeed materials with so-called piezoelectric and pyroelectric properties and we use them for sensors and actuators. More confusingly, there is a thermoelectric effect relating electric current and heat flux. In order to set the ideas correctly, we explain these phenomena and introduce to the abstract world of electromagnetism and thermomechanics coupling. Furthermore, we provide an inside look to realize how different types of thermal and electric coupling phenomena work and how to model such materials adequately.

  • 2.
    Abali, Bilen Emek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Asymptotic homogenization and parameter determination in metamaterials2021Conference paper (Other academic)
  • 3.
    Abali, Bilen Emek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Energy based methods applied in mechanics by using the extended Noether's formalism2023In: Zeitschrift für angewandte Mathematik und Mechanik, ISSN 0044-2267, E-ISSN 1521-4001, Vol. 103, no 12Article in journal (Refereed)
    Abstract [en]

    Physical systems are modeled by field equations; these are coupled, partial differential equations in space and time. Field equations are often given by balance equations and constitutive equations, where the former are axiomatically given and the latter are thermodynamically derived. This approach is useful in thermomechanics and electromagnetism, yet challenges arise once we apply it in damage mechanics for generalized continua. For deriving governing equations, an alternative method is based on a variational framework known as the extended Noether's formalism. Its formal introduction relies on mathematical concepts limiting its use in applied mechanics as a field theory. In this work, we demonstrate the power of extended Noether's formalism by using tensor algebra and usual continuum mechanics nomenclature. We demonstrate derivation of field equations in damage mechanics for generalized continua, specifically in the case of strain gradient elasticity.

    Download full text (pdf)
    fulltext
  • 4.
    Abali, Bilen Emek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Chair of Continuum Mechanics and Constitutive Theory, Institute of Mechanics, Technische Universität Berlin.
    Modeling magnetohydrodynamics and computation of metal smelting2020In: Energy-based mathematical methods for reactive multiphase flows / [ed] Liero, M.; Mehrmann, V.; Mielke, A.; Peschka, D.; Thomas, M.; Wagner, B., Berlin Mathematics Research Center MATH , 2020, p. 12-13Conference paper (Other academic)
    Abstract [en]

    Ore is a compound including minerals and is found in Earth’s crust. Ore may contain iron, aluminum, copper or even gold. Extracting these metals are called smelting. For aluminum, smelting is driven by electromagnetism, where conductive ore is a viscous melt with high temperatures and is set in motion effected by electromagnetic forces. Simulation of such an application necessitates not only a computational framework but also the consistent set of partial differential equations. Thermomechanics and electromagnetism are both well-studied independently; nevertheless, their interaction is still puzzling.

  • 5.
    Abali, Bilen Emek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Aldakheel, Fadi
    Zohdi, Tarek I.
    Multiphysics Computation of Thermomechanical Fatigue in Electronics Under Electrical Loading2022In: Current Trends and Open Problems in Computational Mechanics / [ed] Fadi Aldakheel, Blaž Hudobivnik, Meisam Soleimani, Henning Wessels, Christian Weißenfels, Michele Marino, Cham: Springer Nature, 2022, p. 1-14Chapter in book (Refereed)
  • 6.
    Abali, Bilen Emek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Institute of Mechanics, MS 2, Technische Universität Berlin, Einsteinufer 5, 10587, Berlin, Germany.
    Barchiesi, Emilio
    Additive manufacturing introduced substructure and computational determination of metamaterials parameters by means of the asymptotic homogenization2021In: Continuum Mechanics and Thermodynamics, ISSN 0935-1175, E-ISSN 1432-0959, Vol. 33, no 4, p. 993-1009Article in journal (Refereed)
    Abstract [en]

    Metamaterials exhibit materials response deviation from conventional elasticity. This phenomenon is captured by the generalized elasticity as a result of extending the theory at the expense of introducing additional parameters. These parameters are linked to internal length scales. Describing on a macroscopic level, a material possessing a substructure at a microscopic length scale calls for introducing additional constitutive parameters. Therefore, in principle, an asymptotic homogenization is feasible to determine these parameters given an accurate knowledge on the substructure. Especially in additive manufacturing, known under the infill ratio, topology optimization introduces a substructure leading to higher-order terms in mechanical response. Hence, weight reduction creates a metamaterial with an accurately known substructure. Herein, we develop a computational scheme using both scales for numerically identifying metamaterials parameters. As a specific example, we apply it on a honeycomb substructure and discuss the infill ratio. Such a computational approach is applicable to a wide class substructures and makes use of open-source codes; we make it publicly available for a transparent scientific exchange.

    Download full text (pdf)
    fulltext
  • 7.
    Abali, Bilen Emek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Institute of Mechanics Technische Universität Berlin Einsteinufer 5 Berlin 10967 Germany.
    Klunker, Andre
    Institute of Mechanics Technische Universität Berlin Einsteinufer 5 Berlin 10967 Germany.
    Barchiesi, Emilio
    International Research Center on Mathematics and Mechanics of Complex Systems Università degli Studi dell'Aquila Via Giovanni Gronchi 18 ‐ Zona industriale di Pile L'Aquila 67100 Italy.
    Placidi, Luca
    Engineering Faculty International Telematic University Uninettuno Corso Vittorio Emanuele II Rome 39 00186 Italy.
    A novel phase‐field approach to brittle damage mechanics of gradient metamaterials combining action formalism and history variable2021In: Zeitschrift für angewandte Mathematik und Mechanik, ISSN 0044-2267, E-ISSN 1521-4001, Vol. 101, no 9, article id e202000289Article in journal (Refereed)
    Abstract [en]

    Metamaterials response is generally modeled by generalized continuum based theories. Their inherent substructure leads to a necessity for higher-order theories, and especially in damage mechanics, such a generalization is difficult to acquire. We exploit the action formalism in order to obtain the governing equations in generalized damage mechanics for metamaterials. Additionally, by using auxilliary variables, the variational formulation is endowed with the first rate of damage variable that is missing in standard approaches. The presented action formalism with auxilliary variables leads directly to the weak form. We implement a finite element method based approach by using open-source computing platform called FEniCS and solve this weak in order to obtain the deformation and damage numerically. Metamaterials simulations are demonstrated for simple geometries in mixed mode (I and II) as well as in mode III.

    Download full text (pdf)
    fulltext
  • 8.
    Abali, Bilen Emek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Vazic, Bozo
    Univ Utah, Dept Mech Engn, Salt Lake City, UT USA..
    Newell, Pania
    Univ Utah, Dept Mech Engn, Salt Lake City, UT USA..
    Influence of microstructure on size effect for metamaterials applied in composite structures2022In: Mechanics research communications, ISSN 0093-6413, E-ISSN 1873-3972, Vol. 122, article id 103877Article in journal (Refereed)
    Abstract [en]

    Microstructure related deviation from elastic response is known as "size-effect."Metamaterials - for example modeled by strain gradient elasticity - capture this effect adequately by means of additional parameters to be determined. We employ a methodology based on asymptotic homogenization in order to obtain metamaterials parameters and then present the influence of these additional parameters by using simulations. By means of the finite element method, we solve metamaterials deformation modeled by the strain gradient elasticity. The implementation is established by open-source packages (FEniCS) for a realistic, composite structure with round and oval inclusions.

    Download full text (pdf)
    fulltext
  • 9.
    Abali, Bilen Emek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Yardimci, Mert Yucel
    Univ Ghent, Magnel Vandepitte Lab, Dept Struct Engn & Bldg Mat, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium.;Istanbul Okan Univ, Dept Civil Engn, TR-34959 Istanbul, Turkey..
    Zecchini, Michele
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria..
    Daisse, Gilda
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria..
    Marchesini, Flavio H.
    Univ Ghent, Dept Mat Text & Chem Engn, Technol Pk Zwijnaarde 130, B-9052 Ghent, Belgium..
    De Schutter, Geert
    Univ Ghent, Magnel Vandepitte Lab, Dept Struct Engn & Bldg Mat, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium..
    Wan-Wendner, Roman
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria.;Univ Ghent, Magnel Vandepitte Lab, Dept Struct Engn & Bldg Mat, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium..
    Experimental investigation for modeling the hardening of thermosetting polymers during curing2021In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 102, article id 107310Article in journal (Refereed)
    Abstract [en]

    During curing of thermosetting polymers, crosslinking results in hardening or stiffening of the material. In electronics, for example in encapsulating integrated circuits (die bonding), thermosets are fully cured in a controlled environment (under UV-light or within a thermal oven) such that the highest stiffness possible has been achieved. In building materials, specifically in thermosets used in fastening systems (adhesive anchoring), hardening occurs at environmental temperature. Daily temperature variations alter the curing process and possibly lead to a lower stiffness. We demonstrate a modeling approach for the mechanical response dependency on the degree of cure by means of rheometer measurements under a specific temperature profile. Precisely, we perform oscillatory rheometric tests and convert the storage and loss moduli to material parameters depending on the degree of cure. Moreover, the temperature dependency as well as chemical shrinkage have been determined by the same experimental protocol. The presented approach has been applied to a commercially available (epoxy) thermoset used as an adhesive. We have observed a hardening after a gelation point of 0.7 and an adequate fit for mechanical response by polynomial functions of degree four.

    Download full text (pdf)
    fulltext
  • 10.
    Abali, Bilen Emek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria.
    Zecchini, Michele
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria.
    Daissè, Gilda
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria.
    Czabany, Ivana
    BOKU Univ Nat Resources & Life Sci, Dept Mat Sci & Proc Engn, Inst Wood Technol & Renewable Mat, Konrad Lorenz Str 24, A-3430 Tulln, Austria.
    Gindl-Altmutter, Wolfgang
    BOKU Univ Nat Resources & Life Sci, Dept Mat Sci & Proc Engn, Inst Wood Technol & Renewable Mat, Konrad Lorenz Str 24, A-3430 Tulln, Austria.
    Wan-Wendner, Roman
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria; Univ Ghent, Dept Struct Engn & Bldg Mat, Magnel Lab, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium.
    Cure Kinetics and Inverse Analysis of Epoxy-Amine Based Adhesive Used for Fastening Systems2021In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 14, no 14, article id 3853Article in journal (Refereed)
    Abstract [en]

    Thermosetting polymers are used in building materials, for example adhesives in fastening systems. They harden in environmental conditions with a daily temperature depending on the season and location. This curing process takes hours or even days effected by the relatively low ambient temperature necessary for a fast and complete curing. As material properties depend on the degree of cure, its accurate estimation is of paramount interest and the main objective in this work. Thus, we develop an approach for modeling the curing process for epoxy based thermosetting polymers. Specifically, we perform experiments and demonstrate an inverse analysis for determining parameters in the curing model. By using calorimetry measurements and implementing an inverse analysis algorithm by using open-source packages, we obtain 10 material parameters describing the curing process. We present the methodology for two commercial, epoxy based products, where a statistical analysis provides independence of material parameters leading to the conclusion that the material equation is adequately describing the material response.

    Download full text (pdf)
    FULLTEXT01
  • 11.
    Abdelki, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Fused deposition modeling of API-loaded mesoporous magnesium carbonate2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, the incorporation of drug loaded mesoporous magnesium carbonate as an excipient for the additive manufacturing of oral tablets by fused deposition modeling was investigated. Cinnarizine, a BCS class II drug, was loaded into the pores of the mesoporous material via a soaking method, corresponding to a drug loading of 8.68 wt%. DSC measurements on the loaded material suggested that the drug was partially crystallized after incorporation, meanwhile the XRD diffractogram implied that the drug was in a state lacking long range order. The drug loaded material was combined with two pharmaceutical polymers, Aquasolve LG and Klucel ELF, and extruded into filaments with a single screw extruder. Filaments of Klucel ELF and drug loaded Upsalite (30:70 wt% ratio) were successfully implemented for the printing oral tablets, in contrast to the Aquasolve LG based filaments which were difficult to print due to thickness variations and non-uniform material distributions. The drug content obtained by TGA suggested drug loadings of 7.71 wt% and 2.23 wt% in the drug loaded Upsalite and tablets respectively. Dissolution studies using an USP II apparatus showed a slower API-release from the tablets in comparison to the crystalline drug, most probably due to slow diffusion of drug species through the polymeric matrix. For future studies, pharmaceutical polymers with higher aqueous solubility should be investigated in order to thoroughly examine the potential of utilizing the immediate release property of Upsalite.

    Download full text (pdf)
    fulltext
  • 12.
    Abdel-Magied, Ahmed F.
    et al.
    KTH Royal Inst Technol, Dept Chem Engn, S-100 44 Stockholm, Sweden.;Nucl Mat Author, POB 530,El Maadi, Cairo, Egypt..
    Ashour, Radwa M.
    KTH Royal Inst Technol, Dept Chem Engn, S-100 44 Stockholm, Sweden.;Nucl Mat Author, POB 530,El Maadi, Cairo, Egypt..
    Fu, Le
    Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China..
    Dowaidar, Moataz
    King Fahd Univ Petr & Minerals KFUPM, Dept Bioengn, Dhahran 31261, Saudi Arabia..
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science.
    Forsberg, Kerstin
    KTH Royal Inst Technol, Dept Chem Engn, S-100 44 Stockholm, Sweden..
    Abdelhamid, Hani Nasser
    Assiut Univ, Dept Chem, Adv Multifunct Mat Lab, Assiut 71515, Egypt.;Stockholm Univ, Dept Mat & Environm Chem, SE-10691 Stockholm, Sweden..
    Magnetic metal-organic frameworks for efficient removal of cadmium(II), and lead(II) from aqueous solution2022In: Journal of Environmental Chemical Engineering, E-ISSN 2213-3437, Vol. 10, no 3, article id 107467Article in journal (Refereed)
    Abstract [en]

    Efficient and convenient methods for the removal of toxic heavy metal ions especially Cd(II) and Pb(II) from aqueous solutions is of great importance due to their serious threat to public health and the ecological system. In this study, two magnetic metal-organic frameworks (namely: Fe3O4@ZIF-8, and Fe3O4@UiO-66-NH2) were synthesized, fully characterized, and applied for the adsorption of Cd(II) and Pb(II) from aqueous solutions. The adsorption efficiencies for the prepared nanocomposites are strongly dependent on the pH of the aqueous solution. The maximum adsorption capacities of Fe3O4@UiO-66-NH2, and Fe3O4@ZIF-8 at pH 6.0 were calculated to be 714.3 mg.g(-), and 370 mg.g(-1) for Cd(II), respectively, and 833.3 mg.g(-1), and 666.7 mg.g(-1) for Pb(II), respectively. The adsorption process follows a pseudo-second-order model and fit the Langmuir isotherm model. Moreover, the thermodynamic studies revealed that the adsorption process is endothermic, and spontaneous in nature. A plausible adsorption mechanism was discussed in detail. The magnetic adsorbents: Fe3O4@ZIF-8, and Fe3O4@UiO-66-NH2 showed excellent reusability, maintaining the same efficiency for at least four consecutive cycles. These results reveal the potential use of magnetic Fe3O4@ZIF-8, and Fe3O4@UiO-66-NH2 as efficient adsorbents in removing Cd(II) and Pb(II) from aqueous solutions.

    Download full text (pdf)
    fulltext
  • 13.
    Abdulkareem Najm Al-Saedi, Ahmed
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Hedenfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    García, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Kron, Anna-Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Bergström, Cornelia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Källkvist, Lova
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Analysis of Resin Impregnated Non-woven: In collaboration with Hitachi Energy2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    High voltage bushings are the most critical components of power transformers. A common material used in bushings is resin impregnated paper (RIP). Hitachi Energy is investigating whether this can be replaced with a new material, resin impregnated non-woven (RIN). One of the main reasons is that non-woven is less prone to absorb moisture compared to paper. Thus, for design purposes the mechanical, thermal and absorption properties of RIN have been studied and compared to RIP. The mechanical properties were tested by tensile and bending tests at room temperature and 80 ℃, showing that RIN has a lower elastic modulus and tensile strength than RIP at both temperatures. However, it was demonstrated that RIN does not retain its elongation at break and elasticity properties at elevated temperatures. The bending test showed no significant differences in flexural properties for RIN between room and high temperature. The thermal properties were studied with the transient plane source method (TPS) showing that both RIN and RIP had a higher specific heat capacity than pure epoxy. The thermal conductivity of the materials will be measured and included later. Lastly, the water absorption test was performed in order to provide information about the suitability of the materials used in bushings. For this different methods were used; water immersion andwater vapor testing. The immersion test showed that non-woven is more water resistant than paper and that the composites only absorb a small amount of water. No useful information was achieved from the water vapor test due to limited testing time. The results demonstrate the promising potential of RIN in bushings.

    Download full text (pdf)
    fulltext
  • 14.
    Abdulla, Beyar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Nanocellulose surface functionalization for in-situ growth of zeolitic imidazolate framework 67 and 82020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master’s thesis was conducted at the Department of Nanotechnology and Functional Materials at Ångström Laboratory as part of an on-going project to develop hybrid nanocomposites from Cladophora cellulose and a sub-type of metal-organic frameworks; zeolitic imidazolate frameworks (ZIFs). By utilizing a state-of-the-art interfacial synthesis approach, in-situ growth of ZIF particles on the cellulose could be achieved. TEMPO-mediated oxidation was diligently used to achieve cellulose nanofibers with carboxylate groups on their surfaces. These were ion-exchanged to promote growth of ZIF particles in a nanocellulose solution and lastly, metal ions and organic linkers which the ZIFs are composed of were added to the surface functionalized and ion-exchanged nanocellulose solution to promote ZIF growth. By vacuum filtration, mechanical pressing and furnace drying; freestanding nanopapers were obtained. A core-shell morphology between the nanocellulose and ZIF crystals was desired and by adjusting the metal ion concentration, a change in morphologies was expected. The nanocomposites were investigated with several relevant analytical tools to confirm presence, attachment and in-situ growth of ZIF crystal particles upon the surface of the fine nanocellulose fibers. Both the CNF@ZIF-67 and CNF@ZIF-8 nanocomposites were successfully prepared as nanopapers with superior surface areas and thermal properties compared to pure TEMPO-oxidized cellulose nanopapers. The CNF@ZIFs showcased hierarchical porosities, stemming from the micro- and mesoporous ZIFs and nanocellulose, respectively. Also, it was demonstrated that CNF@ZIF-8 selectively adsorbed CO2 over N2. Partial formation of core-shell structure could be obtained, although a relationship between increased metal ions and ZIF particle morphology could not wholly be observed.

    Download full text (pdf)
    fulltext
  • 15.
    Abenayake, Himesha
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Additively Manufactured Rare Earth Free Permanent Magnets2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    It’s well known that MnAl(C) material consists of a metastable phase (τ) with promising ferromagnetic properties, produced either by controlled cooling from the high-temperature hexagonal ε-phase or rapid cooling that freezes the ε-phase followed by low-temperature annealing. Due to the high cooling rates involved, additive manufacturing (AM) especially selective laser melting (SLM), has been identified as a possible method to retain the high-temperature ε-phase, hence containing a potential capacity to produce permanent magnets upon low-temperature annealing. Moreover, the competency of additive manufacturing to address manufacturing design complexity, material scarcity and tailored properties, yields a great opportunity to produce permanent magnets with suitable magnetic properties for complex applications. This work provides a systematic study on three main aspects; development of printing parameters for improved relative density of as-printed MnAl(C) samples; investigation of the influence of scanning strategies on the crystallographic texture of as-printed and annealed samples; investigation of the influence of annealing time and temperature on τ-phase purity and magnetic properties. It was found that laser remelting (multiple laser exposure) combined with specific scanning strategies is a promising path to enhance the relative density of as-printed samples. Some specific scanning strategies were found to be capable of retaining relatively strong crystallographic textured ε-phase in as-printed samples. Following the annealing process for ε→τ transformation, only a partial transformation of crystallographic texture was observed. Characterization of annealed samples through XRD (x-ray diffraction) and phase fractions calculations through Rietveld refinement reveals that relatively short annealing times and low temperatures result in incomplete ε→τ transformation. In addition, longer annealing times and higher temperatures surpass the complete ε→τ transformation and lead to the formation of equilibrium phases subsequently reducing the magnetic performance. Furthermore, the experimental findings demonstrated a pronounced influence of higher carbon content in the powder, resulting in improved magnetic properties.

    Download full text (pdf)
    Additively Manufactured Rare Earth Free Permanent Magnets
  • 16.
    Aboulfadl, Hisham
    et al.
    Chalmers Univ Technol, Dept Phys, Div Microstruct Phys, S-41296 Gothenburg, Sweden..
    Sopiha, Kostiantyn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Keller, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Larsen, Jes K
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Scragg, Jonathan J.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Persson, Clas
    Univ Oslo, Ctr Mat Sci & Nanotechnol, Dept Phys, N-0316 Oslo, Norway.;KTH Royal Inst Technol, Dept Mat Sci & Engn, Div Appl Mat Phys, S-10044 Stockholm, Sweden..
    Thuvander, Mattias
    Chalmers Univ Technol, Dept Phys, Div Microstruct Phys, S-41296 Gothenburg, Sweden..
    Edoff, Marika
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Alkali Dispersion in (Ag,Cu)(In,Ga)Se-2 Thin Film Solar Cells-Insight from Theory and Experiment2021In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 13, no 6, p. 7188-7199Article in journal (Refereed)
    Abstract [en]

    Silver alloying of Cu(In,Ga)Se-2 absorbers for thin film photovoltaics offers improvements in open-circuit voltage, especially when combined with optimal alkali-treatments and certain Ga concentrations. The relationship between alkali distribution in the absorber and Ag alloying is investigated here, combining experimental and theoretical studies. Atom probe tomography analysis is implemented to quantify the local composition in grain interiors and at grain boundaries. The Na concentration in the bulk increases up to similar to 60 ppm for [Ag]/([Ag] + [Cu]) = 0.2 compared to similar to 20 ppm for films without Ag and up to similar to 200 ppm for [Ag]/([Ag] + [Cu]) = 1.0. First-principles calculations were employed to evaluate the formation energies of alkali-on-group-I defects (where group-I refers to Ag and Cu) in (Ag,Cu)(In,Ga)Se-2 as a function of the Ag and Ga contents. The computational results demonstrate strong agreement with the nanoscale analysis results, revealing a clear trend of increased alkali bulk solubility with the Ag concentration. The present study, therefore, provides a more nuanced understanding of the role of Ag in the enhanced performance of the respective photovoltaic devices.

    Download full text (pdf)
    FULLTEXT01
  • 17.
    Aboulsaad, Mustafa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    El Tahan, Ayman
    Soliman, Moataz
    El-Sheikh, Shaker
    Ebrahim, Shaker
    Thermal oxidation of sputtered nickel nano-film as hole transport layer for high performance perovskite solar cells2019In: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 30, no 22, p. 19792-19803Article in journal (Refereed)
    Abstract [en]

    The effect of rapid oxidation temperature on the sputtered nickel (Ni) films to act as a hole transport layer (HTL) for perovskite solar cell (PSCs) was investigated. A nano-sputtered Ni film with a thickness about 100 nm was oxidized at a range of different oxidation temperatures between 350 and 650 °C to work as HTL in an inverted p–i–n configuration. DC Hall measurement in van der Pauw configuration and photoluminescence spectroscopy were used to measure the charge’s mobility and extraction of nickel oxide (NiO) films. The behaviour of the carrier concentration measurements of NiO layers at different oxidation temperatures showed that the Ni layer oxidized at 450 °C had the highest carrier concentration among the other samples. The performance measurements of the fabricated PSCs showed that the nickel oxide hole-transporting layer which has been oxidized at the optimum oxidation temperature of 450 °C has the highest power conversion efficiency (PCE) of 12.05%. Moreover, the characteristic parameters of the optimum cell such as the open-circuit voltage (VOC), short-circuit current density (JSC) and fill factor (FF) were 0.92 V, 19.80 mA/cm2 and 0.331, respectively.

    Download full text (pdf)
    fulltext
  • 18.
    Abousharieha, Samah
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Atif, Abdul Raouf
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    3D-printed device providing volumetric compression and strain for cortical brain organoids2023Other (Other academic)
  • 19.
    Abousharieha, Samah
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Atif, Abdul-Raouf
    Mestres, Gemma
    Tenje, Maria
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    A 3D-Printed Device Providing Mechanical Strain for Matrigel-Incorprated Organoids2022Conference paper (Other academic)
  • 20.
    Abrahamsson, Josefine
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Biomarkers and age-related diseases: An overview of how biomarkers can be used to prevent age-related diseases2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Medical devices are becoming more and more implemented for use at home and in parallel, the interest from humans in their own health is increasing. Age-related diseases such as diabetes, cancer, and dementia, to name a few, are examples of diseases that with an early diagnosis could be prevented. To find out if there are early indications of the disease in the body, it is necessary to measure biomarkers. These can be measured either invasive or non-invasive and today they are often measurable only clinically at a hospital, but how can people measure these at home by themselves?

    To investigate this, a literature study has been done with focus on age-related diseases. A total of 49 abstracts were read through to determine relevance to the questions of inquiry and three articles were mainly used in the literature study. It was found that there is research focusing on the use of biomarkers to identify and do earlier diagnosing of age-related diseases. Methodology and technology for measuring glucose to identify diabetes are implemented, and a change in lifestyle can prevent a person from being affected by type 2 diabetes. With this knowledge, it is easier to see opportunities for other diseases by using the same type of method and technology further on. A previously conducted study regarding diabetes focus on dietary variations and physical activity for non-diabetic people. Meanwhile in the cancer and dementia area, where the developments are not as successful, the focus is on earlier diagnosing by combining technologies.

    In the future, the technology should be developed so that biomarkers can be used as indicators of the diseases cancer and dementia, and not just as a complement to already applied technology such as imaging techniques that are available today.

    Download full text (pdf)
    fulltext
  • 21.
    Adeleye, Damilola
    et al.
    Univ Luxembourg, Esch Sur Alzette, Luxembourg.
    Sood, Mohit
    Törndahl, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology. University of Luxembourg, Esch-sur-Alzette, Luxembourg.
    Hultqvist, Adam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology. University of Luxembourg, Esch-sur-Alzette, Luxembourg.
    Vanderhaegen, Aline
    Melchiorre, Michele
    Siebentritt, Susanne
    Mitigation of Phase Separation in High Ga Cu(In,Ga)S2 Absorbers to Achieve ∼ 1 Volt 15.6% Power Conversion Efficiency2023In: 2023 IEEE 50th Photovoltaic Specialists Conference (PVSC), Institute of Electrical and Electronics Engineers (IEEE), 2023Conference paper (Refereed)
    Abstract [en]

    The use of Cu(In,Ga)S2 as a top cell in tandem solar cell, despite having suitable properties for such an application, is hampered by a high open-circuit voltage (VOC) deficit. The deficit arises from a poor optoelectronic quality of the absorbers - engendered by phase separation - and the inadequate translation of the optoelectronic quality of the absorber into device VOC. In this work, we report the role of first stage substrate temperature in the mitigation of phase separation and optimized Cu-excess during growth in Cu(In,Ga)S2, which leads to reduced VOC deficit, resulting in a device with 15.6 % PCE with a VOC of ∼ 981 mV when completed with atomic layer deposited (Zn,Sn)O and Al:ZnMgO transparent conductive oxide.

  • 22.
    Adiba, Adiba
    et al.
    Aligarh Muslim Univ, Dept Phys, Aligarh 202002, India..
    Pandey, Vidit
    Aligarh Muslim Univ, Dept Phys, Aligarh 202002, India..
    Ahmad, Tufail
    Aligarh Muslim Univ, Dept Phys, Aligarh 202002, India..
    Nehla, Priyanka
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Munjal, Sandeep
    Natl Forens Sci Univ, Ponda 403401, Goa, India.;Univ Delhi, Dept Phys & Astrophys, New Delhi 110007, India..
    Multilevel resistive switching with negative differential resistance in Al/ NiO/ZnFe2O4/ITO ReRAM device2023In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 654, article id 414742Article in journal (Refereed)
    Abstract [en]

    The Resistive Random Access Memory devices have emerged as an energy-efficient alternative to Von Neumann computers by enabling in-memory computing. Here we demonstrate bipolar resistive switching in thin films of Nickel oxide (NiO) and Zinc Ferrite (ZFO) using a simple Al/NiO/ZFO/ITO configuration, making them a possible candidate for the next generation memory devices. The fabricated device demonstrated excellent resistive switching behavior with high endurance for up to 1000 cycles, good retention for more than 10(4) s, and a good resistance ratio of HRS to LRS similar to 10(2). Ohmic conduction was observed in the LRS, while in the HRS, along with ohmic conduction, space charge limited current (SCLC) and Schottky mechanisms were observed. Besides the LRS and HRS, a number of stable intermediate resistance states can also be obtained during the RESET process using different stop voltages, which makes the current device a multilevel resistive switching device.

  • 23.
    Afewerki, Samson
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Stocco, Thiago Domingues
    Rosa da Silva, André Diniz
    Aguiar Furtado, André Sales
    Fernandes de Sousa, Gustavo
    Ruiz-Esparza, Guillermo U
    Webster, Thomas J
    Marciano, Fernanda R
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Zhang, Yu Shrike
    Lobo, Anderson Oliveira
    In vitro high-content tissue models to address precision medicine challenges2023In: Molecular Aspects of Medicine, ISSN 0098-2997, E-ISSN 1872-9452, Vol. 91, article id 101108Article in journal (Refereed)
    Abstract [en]

    The field of precision medicine allows for tailor-made treatments specific to a patient and thereby improve the efficiency and accuracy of disease prevention, diagnosis, and treatment and at the same time would reduce the cost, redundant treatment, and side effects of current treatments. Here, the combination of organ-on-a-chip and bioprinting into engineering high-content in vitro tissue models is envisioned to address some precision medicine challenges. This strategy could be employed to tackle the current coronavirus disease 2019 (COVID-19), which has made a significant impact and paradigm shift in our society. Nevertheless, despite that vaccines against COVID-19 have been successfully developed and vaccination programs are already being deployed worldwide, it will likely require some time before it is available to everyone. Furthermore, there are still some uncertainties and lack of a full understanding of the virus as demonstrated in the high number new mutations arising worldwide and reinfections of already vaccinated individuals. To this end, efficient diagnostic tools and treatments are still urgently needed. In this context, the convergence of bioprinting and organ-on-a-chip technologies, either used alone or in combination, could possibly function as a prominent tool in addressing the current pandemic. This could enable facile advances of important tools, diagnostics, and better physiologically representative in vitro models specific to individuals allowing for faster and more accurate screening of therapeutics evaluating their efficacy and toxicity. This review will cover such technological advances and highlight what is needed for the field to mature for tackling the various needs for current and future pandemics as well as their relevancy towards precision medicine.

  • 24.
    Afewerki, Samson
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Wang, Xichi
    Ruiz-Esparza, Guillermo U.
    Tai, Cheuk-Wai
    Kong, Xueying
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Zhou, Shengyang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Welch, Ken
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Huang, Ping
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Bengtsson, Rhodel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Xu, Chao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Combined Catalysis for Engineering Bioinspired, Lignin-Based, Long-Lasting, Adhesive, Self-Mending, Antimicrobial Hydrogels2020In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 14, no 12, p. 17004-17017Article in journal (Refereed)
    Abstract [en]

    The engineering of multifunctional biomaterials using a facile sustainable methodology that follows the principles of green chemistry is still largely unexplored but would be very beneficial to the world. Here, the employment of catalytic reactions in combination with biomass-derived starting materials in the design of biomaterials would promote the development of eco-friendly technologies and sustainable materials. Herein, we disclose the combination of two catalytic cycles (combined catalysis) comprising oxidative decarboxylation and quinone-catechol redox catalysis for engineering lignin-based multifunctional antimicrobial hydrogels. The bioinspired design mimics the catechol chemistry employed by marine mussels in nature. The resultant multifunctional sustainable hydrogels (1) are robust and elastic, (2) have strong antimicrobial activity, (3) are adhesive to skin tissue and various other surfaces, and (4) are able to self-mend. A systematic characterization was carried out to fully elucidate and understand the facile and efficient catalytic strategy and the subsequent multifunctional materials. Electron paramagnetic resonance analysis confirmed the long-lasting quinone-catechol redox environment within the hydrogel system. Initial in vitro biocompatibility studies demonstrated the low toxicity of the hydrogels. This proof-of-concept strategy could be developed into an important technological platform for the eco-friendly, bioinspired design of other multifunctional hydrogels and their use in various biomedical and flexible electronic applications.

  • 25.
    Afshar, R.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Stjärnesund, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Gamstedt, E. K.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Girlanda, O.
    Hitachi Energy Res Sweden, Västerås, Sweden.
    Sahlen, F.
    ABB Corp Res, Västerås, Sweden.
    Tjahjanto, D.
    NKT HV Cables Abtechnol Consulting, Västerås, Sweden.
    A micro-CT investigation of densification in pressboard due to compression2023In: Strain, ISSN 0039-2103, E-ISSN 1475-1305, Vol. 59, no 4, article id 12442Article in journal (Refereed)
    Abstract [en]

    As a non-destructive inspection method, micro-computed tomography has been employed for determining local properties of a cellulose-based product, specifically pressboard. Furthermore, by utilizing the determined properties in a detailed numerical model, by means of a finite element analysis, we demonstrate a continuum anisotropic viscoelastic-viscoplastic model. Through such a combination of non-invasive experiments with accurate computations in mechanics, we attain a better understanding of materials and its structural integrity at a pre-production stage increasing the success of the first prototype. In detail, this combination of micro-computed tomography and finite element analysis improves accuracy in predicting materials response by taking into account the local material variations. Specifically, we have performed indentation tests and scanned the internal structure of the specimen for analysing the densification patterns within the material. Subsequently, we have used a developed material model for predicting the response of material to indentation. We have computed the indentation test itself by simulating the mechanical response of high-density cellulose-based materials. In the end, we have observed that pressboard, having initially a heterogeneous density distribution through the thickness, shows a shift in the densification to the more porous part after indentation. The densification maps of the simulated results are presented by comparing with the experimental results. A reasonable agreement is observed between the experimental and the simulated densifications patterns, which suggests that the proposed methodology can be used to predict densification also for other fibre-based materials during manufacturing or in service loading.

    Download full text (pdf)
    fulltext
  • 26.
    Afshar, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Size effect on mechanical properties of wood in transverse direction2022Conference paper (Refereed)
  • 27.
    Afshar, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Uppsala University.
    Alavyoon, Navid
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Ahlgren, A
    Swedish National Maritime and Transport Museums, the Vasa Museum, Stockholm, Sweden.
    Gamstedt, E. Kristofer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Full scale finite element modelling and analysis of the 17th-century warship vasa: A methodological approach and preliminary results2021In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 231, no 111765Article in journal (Refereed)
    Download full text (pdf)
    fulltext
  • 28.
    Afshar, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Uppsala University.
    Cheylan, Matthieu
    École Nationale Supérieure de Mécanique et des Microtechniques, Besançon.
    Almkvist, Gunnar
    Department of Molecular Sciences, Swedish University of Agricultural Sciences.
    Ahlgren, Anders
    The Swedish National Maritime and Transport Museums, The Vasa Museum.
    Gamstedt, E. Kristofer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Uppsala University.
    Creep in oak material from the Vasa ship:: verification of linear viscoelasticity and identification of stress thresholds2020In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 78, no 6, p. 1095-1103Article in journal (Refereed)
    Abstract [en]

    Creep deformation is a general problem for large wooden structures, and in particular for shipwrecks in museums. In this study, experimental creep data on the wooden cubic samples from the Vasa ship have been analysed to confrm the linearity of the viscoelastic response in the directions where creep was detectable (T and R directions). Isochronous stress–strain curves were derived for relevant uniaxial compressive stresses within reasonable time spans. These curves and the associated creep compliance values justify that it is reasonable to assume a linear viscoelastic behaviour within the tested ranges, given the high degree of general variability. Furthermore, the creep curves were ftted with a one-dimensional standard linear solid model, and although the rheological parameters show a fair amount of scatter, they are candidates as input parameters in a numerical model to predict creep deformations. The isochronous stress–strain relationships were used to defne a creep threshold stress below which only negligible creep is expected. These thresholds ranges were 0.3–0.5 MPa in the R direction and 0.05–0.2 MPa in the T direction.

    Download full text (pdf)
    fulltext
  • 29.
    Afshar, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Jeanne, Simon
    Abali, Bilen Emek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Effects of 3-D Printing Infill Density Parameter on the Mechanical Properties of PLA Polymer2023In: Sixty Shades of Generalized Continua: Dedicated to the 60th Birthday of Prof. Victor A. Eremeyev / [ed] Holm Altenbach; Arkadi Berezovski; Francesco dell'Isola; Alexey Porubov, Cham: Springer, 2023, p. 1-12Chapter in book (Refereed)
    Abstract [en]

    This study presents some results on the mechanical behavior of polylactide (PLA) material, produced using the fused deposition modeling (FDM) additive manufacturing technique. We investigate the effect of infill density on the mechanical properties of PLA specimens. We used tensile specimens, prepared according to ISO 527-2 standard, and tested them by a universal testing machine with analysis by means of digital image correlation (DIC) method. The results in terms of UTS and nominal strain at break of PLA material are presented. They demonstrate a significant impact of infill density on material behavior of PLA specimens, as expected. Yet the effect is nonlinear that is indeed valuable to understand. As infill density increases, from 10% to 100%, the nominal strain at break decreases from about 2.1% to 1.2%, respectively. In other words, the material becomes more ductile by decreasing the infill density of PLA material, which is possible to justify with an effect of the microstructure created by the infill density. There is a transition of this observed behavior, from being more ductile to more brittle, by increasing the infill density of the PLA specimens.

  • 30.
    Afshar, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Jeanne, Simon
    Abali, Bilen Emek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Nonlinear Material Modeling for Mechanical Characterization of 3-D Printed PLA Polymer With Different Infill Densities2023In: Applied Composite Materials, ISSN 0929-189X, E-ISSN 1573-4897, Vol. 30, no 3, p. 987-1001Article in journal (Refereed)
    Abstract [en]

    In additive manufacturing, also called 3-D printing, one of widely used materials is polylactide thermoplastic polymer (PLA) by means of the fused deposition modeling. For weight reduction purposes, infill density is an often used feature in slicing for 3-D printing. We aim at investigating the effect of infill density on the mechanical properties of structures. Therefore, we demonstrate how to prepare tensile specimens and test them by a universal testing machine. Results are collected by a so-called digital image correlation method. As infill density increases, from 10% to 100%, the nominal strain at break decreases from about 2.1% to 1.2%, respectively. In other words, the material becomes more ductile by decreasing the infill density of PLA material, which is possible to justify with an effect of the microstructure created by the infill density. Furthermore, we discuss a possible material model fitting all the presented results and report that a hyperelastic material model is needed for the PLA. We utilize Neo-Hookean, Mooney–Rivlin, and Yeoh models, all for different infill densities. All three models show a fairly good agreement to the experimental data. Neo-Hookean model has an advantage of only one parameter, which increases monotonously with infill density.

    Download full text (pdf)
    fulltext
  • 31.
    Aghoutane, Youssra
    et al.
    Biotechnology Agroalimentary and Biomedical Analysis Group, Department of Biology, Faculty of Sciences, Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco; Sensor Electronic & Instrumentation Group, Department of Physics, Faculty of Sciences, Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco.
    Diouf, Alassane
    Biotechnology Agroalimentary and Biomedical Analysis Group, Department of Biology, Faculty of Sciences, Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco; Sensor Electronic & Instrumentation Group, Department of Physics, Faculty of Sciences, Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Bouchikhi, Benachir
    Sensor Electronic & Instrumentation Group, Department of Physics, Faculty of Sciences, Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco.
    El Bari, Nezha el bari
    Biotechnology Agroalimentary and Biomedical Analysis Group, Department of Biology, Faculty of Sciences, Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco.
    Development of a molecularly imprinted polymer electrochemical sensor and its application for sensitive detection and determination of malathion in olive fruits and oils2020In: Bioelectrochemistry, ISSN 1567-5394, E-ISSN 1878-562X, Vol. 132, article id 107404Article in journal (Refereed)
    Abstract [en]

    Malathion (MAL) is an organophosphorus (OP) insecticide. It is a cholinesterase inhibitor, 15 which can pose serious health and environmental problems. In this study, a sensitive and 16 selective molecular imprinted polymer (MIP) based on screen-printed gold electrodes (Au-17 SPE) for MAL detection in olive oils and fruits, was devised. The MIP sensor was prepared 18 using acrylamide as the functional monomer and MAL as the template. Subsequently, the 19 morphology of the electrode surface was studied by scanning electron microscopy (SEM) and 20 atomic force microscopy (AFM). The electrochemical characterization of the developed MIP 21 sensor was performed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), 22 and electrochemical impedance spectroscopy (EIS) techniques. The operational repeatability 23 and stability of the sensor were studied. It was found to have a dynamic concentration range 24 of (0.1 pg mL-1-1000 pg mL-1) and a low limit of detection (LOD) of 0.06 pg mL-1. 25 Furthermore, the sensor was employed to determine MAL content in olive oil with a recovery 26 rate of 87.9% and a relative standard deviation of 8%. It was successfully applied for MAL 27 determination in real samples and promise to open new opportunities for the detection of OP 28 pesticides residues in various food products, as well as in environmental applications.

  • 32.
    Agnihotri, Sagar Narhari
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Liu, Zhenhua
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Barbe, Laurent
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Fornell, Anna
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Droplet Acoustofluidics and Pico-injection for Long-term Cell Culture2022Conference paper (Other academic)
    Download full text (pdf)
    fulltext
  • 33.
    Ahmed, Taha
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Optical Quantum Confinement in Ultrasmall ZnO and the Effect of Size on Their Photocatalytic Activity2020In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 124, no 11, p. 6395-6404Article in journal (Refereed)
    Abstract [en]

    Zinc oxide is a well-known metal oxide semiconductor with a wide direct band gap that offers a promising alternative to titanium oxide in photocatalytic applications. ZnO is studied here as quantum dots (QDs) in colloidal suspensions, where ultrasmall nanoparticles of ZnO show optical quantum confinement with a band gap opening for particles below 9 nm in diameter from the shift of the band edge energies. The optical properties of growing ZnO QDs are determined with Tauc analysis, and a system of QDs for the treatment and degradation of distributed threats is analyzed using an organic probe molecule, methylene blue, whose UV/vis spectrum is analyzed in some detail. The effect of optical properties of the QDs and the kinetics of dye degradation are quantified for low-dimensional ZnO materials in the range of 3-8 nm and show a substantial increase in photocatalytic activity compared to larger ZnO particles. This is attributed to a combined effect from the increased surface area as well as a quantum confinement effect that goes beyond the increased surface area. The results show a significantly higher photocatalytic activity for the QDs between 3 and 6 nm with a complete decolorization of the organic probe molecule, while QDs from 6 nm and upward in diameter show signs of competing reduction reactions. Our study shows that ultrasmall ZnO particles have a reactivity beyond that which is expected because of their increased surface area and also demonstrates size-dependent reaction pathways, which introduces the possibility for size-selective catalysis.

  • 34.
    Ahmed, Taha
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Fondell, Mattis
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Donzel-Gargand, Olivier
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Zhu, Jiefang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Preparation and characterisation of ZnO/Fe2O3 core–shell nanorodsManuscript (preprint) (Other academic)
    Abstract [en]

    ZnO is a widely used semiconductor photocatalyst. However, the bandgap of ZnO is too large to utilise visible light or solar energy. Therefore, ZnO can couple with a narrow band gap semiconductor that is a visible-light-responsive photocatalyst. ZnO can help with charge seperation through attracting electrons or holes from the other semiconductor. In this work, ZnO nanorods were electrodeposited on FTO glass, and then coated with ultrathin layer of Fe2O3 via ALD.

    SEM, TEM, XPS, Raman and UV-Vis spectroscopies were used to characterise the prepared samples. Raman shows that ALD-coated Fe2O3 is hematite (α-Fe2O3). The prepared ZnO/Fe2O3 shows photocatalytic activity of EBT degradation under visible light illumination. The synthetic strategy can also beextended to prepare other heterostructured photocatalysts.

  • 35.
    Ahmed, Taha
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Thyr, Jakob
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Naim Katea, Sarmad
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Westin, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Phonon–phonon and electron–phonon coupling in nano-dimensional ZnOManuscript (preprint) (Other academic)
    Abstract [en]

    Thermal losses through vibrational coupling are critical bottlenecks limiting several materials classes from reaching their full potential. Altering the phonon–phonon and electron–phonon coupling by controlled suppression of vibrational degrees of freedom through low-dimensionality are promising but still largely unexplored approaches. Here we report a detailed study of the first- and second-order Raman processes as a function of size for low-dimensional ZnO. Wurtzite ZnO nanoparticles were synthesised into 3D frameworks of ZnO crystallites, with tailored crystallite diameters from 10 nm to 150 nm and characterised by electron microscopy, X-ray diffraction and non-resonant and resonant Raman spectroscopy.

    We present a short derivation of how resonance Raman and the relation between the longitudinal optical (LO) phonons can be utilised to quantify the electron–phonon coupling, its merits, and limitations. Theoretical Raman response using density functional theory is corroborating the experimental data in assigning first- and second-order Raman modes. The Lyddane-Sachs-Teller equation was applied to the measured LO–TO split and revealed no change in the ratio between the static and high-frequency dielectric constant with changing ZnO dimension from 10 nm to 150 nm. The second-order Raman revealed a phonon–phonon coupling that generally increased with particle size and markedly so for differential modes. Resonance Raman showed the fundamental LO mode and the 2nd, 3rd, and 4th overtones. The intensity relation between the fundamental LO mode and its overtones enabled the extraction of the change in electron–phonon coupling via the Huang-Rhys parameter as a function of particle size, which showed an increase with particle size.

  • 36.
    Aimonen, Kukka
    et al.
    Finnish Inst Occupat Hlth, Box 40, Helsinki 00032, Finland..
    Suhonen, Satu
    Finnish Inst Occupat Hlth, Box 40, Helsinki 00032, Finland..
    Hartikainen, Mira
    Finnish Inst Occupat Hlth, Box 40, Helsinki 00032, Finland..
    Lopes, Viviana
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Norppa, Hannu
    Finnish Inst Occupat Hlth, Box 40, Helsinki 00032, Finland..
    Ferraz, Natalia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Catalan, Julia
    Finnish Inst Occupat Hlth, Box 40, Helsinki 00032, Finland.;Univ Zaragoza, Dept Anat Embryol & Genet, Zaragoza 50013, Spain..
    Role of Surface Chemistry in the In Vitro Lung Response to Nanofibrillated Cellulose2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 2, article id 389Article in journal (Refereed)
    Abstract [en]

    Wood-derived nanofibrillated cellulose (NFC) has emerged as a sustainable material with a wide range of applications and increasing presence in the market. Surface charges are introduced during the preparation of NFC to facilitate the defibrillation process, which may also alter the toxicological properties of NFC. In the present study, we examined the in vitro toxicity of NFCs with five surface chemistries: nonfunctionalized, carboxymethylated, phosphorylated, sulfoethylated, and hydroxypropyltrimethylammonium-substituted. The NFC samples were characterized for surface functional group density, surface charge, and fiber morphology. Fibril aggregates predominated in the nonfunctionalized NFC, while individual nanofibrils were observed in the functionalized NFCs. Differences in surface group density among the functionalized NFCs were reflected in the fiber thickness of these samples. In human bronchial epithelial (BEAS-2B) cells, all NFCs showed low cytotoxicity (CellTiter-GloVR luminescent cell viability assay) which never exceeded 10% at any exposure time. None of the NFCs induced genotoxic effects, as evaluated by the alkaline comet assay and the cytokinesis-block micronucleus assay. The nonfunctionalized and carboxymethylated NFCs were able to increase intracellular reactive oxygen species (ROS) formation (chloromethyl derivative of 2 ',7 '-dichlorodihydrofluorescein diacetate assay). However, ROS induction did not result in increased DNA or chromosome damage.

    Download full text (pdf)
    FULLTEXT01
  • 37.
    Akbari, Saba
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Networked Embedded Systems.
    Bergman, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Networked Embedded Systems.
    Fredriksson, Jesper
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Feasibility of Communication Between Sensor Nodes On-board Spacecraft Using Multi Layer Insulation2023Conference paper (Refereed)
    Download full text (pdf)
    fulltext
  • 38.
    Akbari, Saba
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Networked Embedded Systems.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Networked Embedded Systems.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Demo: Sensor Node Communication Through Conductive Mesh Placed on Cotton Knit Fabric2023Conference paper (Other academic)
    Download full text (pdf)
    fulltext
  • 39.
    Akbari-Saatlu, Mehdi
    et al.
    Mid Sweden Univ, Dept Elect Design, SE-85170 Sundsvall, Sweden.
    Procek, Marcin
    Mid Sweden Univ, Dept Elect Design, SE-85170 Sundsvall, Sweden.;Silesian Tech Univ, Dept Optoelect, PL-44100 Gliwice, Poland.
    Mattsson, Claes
    Mid Sweden Univ, Dept Elect Design, SE-85170 Sundsvall, Sweden.
    Thungström, Göran
    Mid Sweden Univ, Dept Elect Design, SE-85170 Sundsvall, Sweden.
    Törndahl, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solar Cell Technology.
    Li, Ben
    Guangdong Greater Bay Area Inst Integrated Circui, Guangzhou 510535, Peoples R China.
    Su, Jiale
    Guangdong Greater Bay Area Inst Integrated Circui, Guangzhou 510535, Peoples R China.;Chinese Acad Sci, Inst Microelect, Key Lab Microelect Devices & Integrated Technol, Beijing 100029, Peoples R China.
    Xiong, Wenjuan
    Chinese Acad Sci, Inst Microelect, Key Lab Microelect Devices & Integrated Technol, Beijing 100029, Peoples R China.
    Radamson, Henry H.
    Mid Sweden Univ, Dept Elect Design, SE-85170 Sundsvall, Sweden.;Guangdong Greater Bay Area Inst Integrated Circui, Guangzhou 510535, Peoples R China.;Chinese Acad Sci, Inst Microelect, Key Lab Microelect Devices & Integrated Technol, Beijing 100029, Peoples R China.
    Nanometer-Thick ZnO/SnO2 Heterostructures Grown on Alumina for H2S Sensing2022In: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 5, no 5, p. 6954-6963Article in journal (Refereed)
    Abstract [en]

    Designing heterostructure materials at the nanoscale is a well-known method to enhance gas sensing performance. In this study, a mixed solution of zinc chloride and tin (II) chloride dihydrate, dissolved in ethanol solvent, was used as the initial precursor for depositing the sensing layer on alumina substrates using the ultrasonic spray pyrolysis (USP) method. Several ZnO/SnO2 heterostructures were grown by applying different ratios in the initial precursors. These heterostructures were used as active materials for the sensing of H2S gas molecules. The results revealed that an increase in the zinc chloride in the USP precursor alters the H2S sensitivity of the sensor. The optimal working temperature was found to be 450 degrees C. The sensor, containing 5:1 (ZnCl2: SnCl2 center dot 2H(2)O) ratio in the USP precursor, demonstrates a higher response than the pure SnO2 (similar to 95 times) sample and other heterostructures. Later, the selectivity of the ZnO/SnO2 heterostructures toward 5 ppm NO2, 200 ppm methanol, and 100 ppm of CH4, acetone, and ethanol was also examined. The gas sensing mechanism of the ZnO/SnO2 was analyzed and the remarkably enhanced gas-sensing performance was mainly attributed to the heterostructure formation between ZnO and SnO2. The synthesized materials were also analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, and X-ray photoelectron spectra to investigate the material distribution, grain size, and material quality of ZnO/SnO2 heterostructures.

    Download full text (pdf)
    fulltext
  • 40.
    Al Kouatli, Hakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Achmawi, Mohamed
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Utvärdering av en befintlig plattform för neurofeedback med hjälp av open-source EEG2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Neurofeedback is a type of biofeedback in which subjects learn to use the activity of their own electrical brain waves to respond to a visual or auditory feedback from the activity of the brain. This is done by connecting electrodes to the body to get the brain's electrical activity in the form of encephalogram signals (EEG) which are then calculated and converted into useful feedback.The purpose of this work was to evaluate a neurofeedback platform via an OpenBCI open-source EEG technology that could lead to more accessible neurofeedback for society.This study was conducted with different methods where the focus was on testing and data analysis. The study has included a summary of theory used in neurofeedback, a comprehensive pilot study on an 8-channel open-source EEG neurofeedback platform and some of the ethical aspects behind the technology used and neurofeedback in Sweden. During the work, two different experts were interviewed: Gunilla Radu, founder and owner of Nordic Center of Neurofeedback AB and Jan Rutkowski, who is an engineer in medical engineering at the Uppsala Hospital.The tests with 8-channel EEG with an OpenBCI hardware and software show results from three subjects. The answers from a follow-up survey that subjects were allowed to answer are presented in the report. This was used as an evaluation of the tests performed. The aim of the tests was to give Biohackeri an opportunity to see the potential for a neurofeedback platform and to create a basis for further development of such a platform. The result indicates that a measurement of the brain activity at rest with the technology from OpenBCI shows a higher concentration level in the human body with open eyes compared to closed eyes. In addition, a higher level of relaxation is noticed when resting with eyes closed compared to eyes open. Answers from the survey show that what is important to the test subjects is, among other things, the convenience while testing the technology. In terms of requirements and rules that Neurofeedback therapists must meet, it turned out that in Sweden therapists do not need to have a specific background or education. There are ethical perspectives that Neurofeedback therapists may consider in implementing Neurofeedback Therapy.The conclusion of this project is that the tested 8-channel EEG equipment gives a result that agrees with the presented theory. Thus, a Neurofeedback platform could be built on the commercially available open-source technology, such as the technology from OpenBCI.

    Download full text (pdf)
    Utvärdering av en befintlig plattform för neurofeedback med hjälp av open-source EEG
  • 41.
    Ali Abed, Hussain
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Wah Le Lay, Jonnalie
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Bozic, Marija
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Imedaschvili, Sumay
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Synthesis of Ethylene Glycol bis(succinimidyl succinate): Concept study of an in-house production of key chemical used for manufacturing of a Multiplex Immunoassay chip2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Ethylene glycol bis(succinimidyl succinate), EGS, batches received from an external supplier, that are used for ThermoFisher's Immuno Solid-phase Allergen Chip (ImmunoCAP ISAC) - tests have been malfunctioning, despite approved certificate of analysis (CoA). EGS is a key chemical needed for chemical activation of the glass slides that make up the Multiplex Immunoassay chips, hence in-house production of EGS is suggested in order to gain control of the batch quality. The purpose of this project is to analyze the technical and economical feasibility of producing EGS internally. This literature study examines the synthesis route of the coupling chemical, the purification and analytical equipment required for upscaling, SWOT-analysis for the production, Calculations of Goods Sold (COGS) and Environment, Health & Safety (EHS) management. The total cost of producing 500g of EGS internally is estimated to be ∼42,159.0 - 45,629.0 SEK, or, ∼84.3 - 91.3 SEK/g, saving 250,000 - 750,000 SEK compared to buying EGS from an external supplier. If an intermediate was to be purchased, the company would save between 200,000 - 700,000 SEK. Tetrahydrofuran (THF) which is used when synthesizing the intermediate is categorized as very hazardous and is suspected of causing cancer by REACH, Registration, Evaluation, Authorisation, and restriction of Chemicals, European Union s regulatory law for the production, registration, usage and regulation of chemical substances. The handling of this chemical is avoided if the intermediate is received from a supplier, which in turn is beneficial from an EHS-perspective. Producing EGS either from scratch or by first purchasing the intermediate and then proceeding with the synthesis of EGS, proves to be economically favorable. 

  • 42.
    Ali, Hasan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science. Uppsala Univ, Dept Engn Sci, Appl Mat Sci, Electron Microscopy & Nanoengn, Box 534, S-75121 Uppsala, Sweden..
    Negi, Devendra Singh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden.;Max Planck Inst Solid State Res, Stuttgart Ctr Electron Microscopy, Heisenbergstr 1, D-70569 Stuttgart, Germany..
    Warnatz, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Hjörvarsson, Björgvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Rusz, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Physics. Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science. Uppsala Univ, Dept Engn Sci, Appl Mat Sci, Electron Microscopy & Nanoengn, Box 534, S-75121 Uppsala, Sweden..
    Atomic resolution energy-loss magnetic chiral dichroism measurements enabled by patterned apertures2020In: Physical Review Research, E-ISSN 2643-1564, Vol. 2, no 2, article id 023330Article in journal (Refereed)
    Abstract [en]

    Electron energy-loss magnetic chiral dichroism (EMCD) has the potential to measure magnetic properties of the materials at atomic resolution but the complex distribution of magnetic signals in the zone axis and the overlapping diffraction discs at higher beam convergence angles make the EMCD signal acquisition challenging. Recently, the use of ventilator apertures to acquire the EMCD signals with atomic resolution was proposed. Here we give the experimental demonstration of several types of ventilator apertures and obtain a clear EMCD signal at beam semiconvergence angles of 5 mrad. To simplify the experimental procedures, we propose a modified ventilator aperture which not only simplifies the complex scattering conditions but reduces the influence of lens aberrations on the EMCD signal as compared to the originally proposed ventilator apertures. In addition, this modified aperture can be used to analyze magnetic crystals with various symmetries and we demonstrate this feature by acquiring EMCD signals on different zone axis orientations of an Fe crystal. With the same aperture we obtain EMCD signals with convergence angles corresponding to atomic resolution electron probes. After the theoretical demonstration of the EMCD signal on a zone axis orientation at high beam convergence angles, this work thus overcomes the experimental and methodological hurdles and enables atomic resolution EMCD on the zone axis by using apertures.

    Download full text (pdf)
    FULLTEXT01
  • 43.
    Ali, Hasan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science. Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.;Forschungszentrum Julich, Ernst Ruska Ctr Microscopy & Spect Electrons, D-52425 Julich, Germany..
    Rusz, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Buergler, Daniel E.
    Forschungszentrum Julich, Peter Grunberg Inst, D-52425 Julich, Germany..
    Adam, Roman
    Forschungszentrum Julich, Peter Grunberg Inst, D-52425 Julich, Germany..
    Schneider, Claus M.
    Forschungszentrum Julich, Peter Grunberg Inst, D-52425 Julich, Germany..
    Tai, Cheuk-Wai
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Thersleff, Thomas
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Noise-dependent bias in quantitative STEM-EMCD experiments revealed by bootstrapping2024In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 257, article id 113891Article in journal (Refereed)
    Abstract [en]

    Electron magnetic circular dichroism (EMCD) is a powerful technique for estimating element-specific magnetic moments of materials on nanoscale with the potential to reach atomic resolution in transmission electron microscopes. However, the fundamentally weak EMCD signal strength complicates quantification of magnetic moments, as this requires very high precision, especially in the denominator of the sum rules. Here, we employ a statistical resampling technique known as bootstrapping to an experimental EMCD dataset to produce an empirical estimate of the noise-dependent error distribution resulting from application of EMCD sum rules to bcc iron in a 3-beam orientation. We observe clear experimental evidence that noisy EMCD signals preferentially bias the estimation of magnetic moments, further supporting this with error distributions produced by Monte-Carlo simulations. Finally, we propose guidelines for the recognition and minimization of this bias in the estimation of magnetic moments.

    Download full text (pdf)
    fulltext
  • 44.
    Ali, Hasan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science. Mirpur Univ Sci & Technol MUST, Dept Elect Engn, Mirpur 10250, Ajk, Pakistan.;Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden. .
    Rusz, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Warnatz, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Hjörvarsson, Björgvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science.
    Simultaneous mapping of EMCD signals and crystal orientations in a transmission electron microscope2021In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, article id 2180Article in journal (Refereed)
    Abstract [en]

    When magnetic properties are analysed in a transmission electron microscope using the technique of electron magnetic circular dichroism (EMCD), one of the critical parameters is the sample orientation. Since small orientation changes can have a strong impact on the measurement of the EMCD signal and such measurements need two separate measurements of conjugate EELS spectra, it is experimentally non-trivial to measure the EMCD signal as a function of sample orientation. Here, we have developed a methodology to simultaneously map the quantitative EMCD signals and the local orientation of the crystal. We analyse, both experimentally and by simulations, how the measured magnetic signals evolve with a change in the crystal tilt. Based on this analysis, we establish an accurate relationship between the crystal orientations and the EMCD signals. Our results demonstrate that a small variation in crystal tilt can significantly alter the strength of the EMCD signal. From an optimisation of the crystal orientation, we obtain quantitative EMCD measurements.

    Download full text (pdf)
    fulltext
  • 45.
    Ali, Hasan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science. Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.;Forschungszentrum Julich, Ernst Ruska Ctr Microscopy & Spect Electrons & Pe, D-52425 Julich, Germany..
    Sathyanath, Sharath Kumar Manjeshwar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science.
    Tai, Cheuk-Wai
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Rusz, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Uusimaki, Toni
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Hjörvarsson, Björgvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Thersleff, Thomas
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden..
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science.
    Single scan STEM-EMCD in 3-beam orientation using a quadruple aperture2023In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 251, article id 113760Article in journal (Refereed)
    Abstract [en]

    The need to acquire multiple angle-resolved electron energy loss spectra (EELS) is one of the several critical challenges associated with electron magnetic circular dichroism (EMCD) experiments. If the experiments are performed by scanning a nanometer to atomic-sized electron probe on a specific region of a sample, the precision of the local magnetic information extracted from such data highly depends on the accuracy of the spatial registration between multiple scans. For an EMCD experiment in a 3-beam orientation, this means that the same specimen area must be scanned four times while keeping all the experimental conditions same. This is a non-trivial task as there is a high chance of morphological and chemical modification as well as non-systematic local orientation variations of the crystal between the different scans due to beam damage, contamination and spatial drift. In this work, we employ a custom-made quadruple aperture to acquire the four EELS spectra needed for the EMCD analysis in a single electron beam scan, thus removing the above-mentioned complexities. We demonstrate a quantitative EMCD result for a beam convergence angle corresponding to sub-nm probe size and compare the EMCD results for different detector geometries.

    Download full text (pdf)
    fulltext
  • 46.
    Al-Tikriti, Yassir
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Hansson, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Elastic forces give rise to unusual phase transformations in polyelectrolyte gels: A Raman microscopy studyManuscript (preprint) (Other academic)
  • 47.
    Alvebratt, Caroline
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Dening, Tahnee J
    Åhlén, Michelle
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Cheung, Ocean
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Gogoll, A
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry. Uppsala University.
    Prestidge, Clive A
    Bergström, Christel A. S.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    In Vitro Performance and Chemical Stability of Lipid-Based Formulations Encapsulated in a Mesoporous Magnesium Carbonate Carrier2020In: Pharmaceutics, ISSN 1999-4923, E-ISSN 1999-4923, Vol. 12, no 5, article id 426Article in journal (Refereed)
    Abstract [en]

    Lipid-based formulations can circumvent the low aqueous solubility of problematic drug compounds and increase their oral absorption. As these formulations are often physically unstable and costly to manufacture, solidification has been suggested as a way to minimize these issues. This study evaluated the physicochemical stability and in vitro performance of lipid-loaded mesoporous magnesium carbonate (MMC) particles with an average pore size of 20 nm. A medium chain lipid was loaded onto the MMC carrier via physical adsorption. A modified in vitro lipolysis setup was then used to study lipid release and digestion with 1H nuclear magnetic resonance spectroscopy. The lipid loading efficiency with different solidification techniques was also evaluated. The MMC, unlike more commonly used porous silicate carriers, dissolved during the lipolysis assay, providing a rapid release of encapsulated lipids into solution. The digestion of the dispersed lipid-loaded MMC therefore resembled that of a coarse dispersion of the lipid. The stability data demonstrated minor degradation of the lipid within the pores of the MMC particles, but storage for three months did not reveal extensive degradation. To conclude, lipids can be adsorbed onto MMC, creating a solid powder from which the lipid is readily released into the solution during in vitro digestion. The chemical stability of the formulation does however merit further attention.

    Download full text (pdf)
    fulltext
  • 48.
    Alvebratt, Caroline
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy. Uppsala University.
    Karlén, Filip
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Åhlén, Michelle
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Edueng, Khadijah
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Dubbelboer, Ilse Rebekka
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Bergström, Christel Anna Sofia
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Two is better than one: benefits of combining supersaturating and solubilizing effectsManuscript (preprint) (Other academic)
  • 49.
    Alvebratt, Caroline
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Keemink, Janneke
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Edueng, Khadijah
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Cheung, Ocean
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Bergström, Christel
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    An in vitro dissolution–digestion–permeation assay for the study of advanced drug delivery systems2020In: European journal of pharmaceutics and biopharmaceutics, ISSN 0939-6411, E-ISSN 1873-3441, Vol. 149, p. 21-29Article in journal (Refereed)
    Abstract [en]

    Advanced drug delivery systems (ADDS) are widely explored to overcome poor aqueous solubility of orally administered drugs. However, the prediction of their in vivo performance is challenging, as in vitro models typically do not capture the interplay between processes occurring in the gut. In additions, different models are used to evaluate the different systems. We therefore present a method that allows monitoring of luminal processing (dissolution, digestion) and its interplay with permeation to better inform on the absorption of felodipine formulated as ADDS. Experiments were performed in a µFLUX-apparatus, consisting of two chambers, representing the intestinal and serosal compartment, separated by Caco-2 monolayers. During dissolution–digestion–permeation experiments, ADDS were added to the donor compartment containing simulated intestinal fluid and immobilized lipase. Dissolution and permeation in both compartments were monitored using in situ UV-probes or, when turbidity interfered the measurements, with HPLC analysis.

    The method showed that all ADDS increased donor and receiver concentrations compared to the condition using crystalline felodipine. A poor correlation between the compartments indicated the need for an serosal compartment to evaluate drug absorption from ADDS. The method enables medium-throughput assessment of: (i) dynamic processes occurring in the small intestine, and (ii) drug concentrations in real-time.

    Download full text (pdf)
    fulltext
  • 50.
    Alyounes, Qsai
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Razan, Alkari
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Characterization of monkey fat tissues: To assist their viability for fat intra-body communication as an early step of non-human primate testing (NHP)2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Fat intra-body communication is a newly proven concept that is built on using human fat tissues as a communication channel for electromagnetic waves inside the body. This allows for two implanted external devices to connect through an intra-body closed-loop communication channel. This concept utilizes the fact that the fat tissues have low dielectric properties and are located between two tissue layers, skin and muscle, which have high dielectric permittivity and high loss tangent so that the signal propagates and confines with lower losses within the fat tissue. In this study, the eligibility of using monkey fat tissues as a communication channel for intra-body communication is being investigated. This comes as a first step in a long process of testing implementing medical devices, mainly prosthetic limbs, on non-human primates using fat-IBC at microwave frequencies. To be able to do that, an experimental characterization of ex-vivo monkey fat, skin, and muscle tissues to explore their dielectric properties compared to those of humans is being carried out. This study of the dielectric properties of monkey tissues is the first of its kind to be carried out on two samples of ex-vivo monkey tissues. Calf tissues have also been investigated in the study to get an insight on the potential differences between human and non-human body tissues in general before doing measurements on monkey tissues. For the measurements, an RF network analyzer and an open-ended coaxial probe method have been implemented. Phantoms that mimic the human tissues have been fabricated to be used as a reference point. The initial investigation demonstrates that calf fat tissues have much higher dielectric properties than human fat tissues. Monkey fat, muscle, and skin tissues showed many similarities to human tissues regarding their dielectric properties. This indicates that monkey tissues can be used for fat intra-body communication. Future numerical and analytical modeling of the monkey tissues needs to be conducted to confirm and strengthen this finding.

    Download full text (pdf)
    fulltext
1234567 1 - 50 of 1633
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf