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  • 151.
    Aiempanakit, Montri
    et al.
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Helmersson, Ulf
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Aijaz, Asim
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Larsson, Petter
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Magnusson, Roger
    Laboratory of Applied Optics, Linköping University.
    Jensen, Jens
    Thin Film Physics Division, IFM, Materials Physics, Linköping University.
    Kubart, Tomáš
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Effect of peak power in reactive high power impulse magnetron sputtering of titanium dioxide2011Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 205, nr 20, s. 4828-4831Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of peak power in a high power impulse magnetron sputtering (HiPIMS) reactive deposition of TiO(2) films has been studied with respect to the deposition rate and coating properties. With increasing peak power not only the ionization of the sputtered material increases but also their energy. In order to correlate the variation in the ion energy distributions with the film properties, the phase composition, density and optical properties of the films grown with different HiPIMS-parameters have been investigated and compared to a film grown using direct current magnetron sputtering (DCMS). All experiments were performed for constant average power and pulse on time (100W and 35 mu s, respectively), different peak powers were achieved by varying the frequency of pulsing. Ion energy distributions for Ti and O and its dependence on the process conditions have been studied. It was found that films with the highest density and highest refractive index were grown under moderate HiPIMS conditions (moderate peak powers) resulting in only a small loss in mass-deposition rate compared to DCMS. It was further found that TiO2 films with anatase and rutile phases can be grown at room temperature without substrate heating and without post-deposition annealing.

  • 152.
    Aiempanakit, Montri
    et al.
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Larsson, Petter
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Sarakinos, Kostas
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Jensen, Jens
    Thin Film Physics Division , IFM, Material Physics, Linköping University.
    Helmersson, Ulf
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Hysteresis and process stability in reactive high power impulse magnetron sputtering of metal oxides2011Inngår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, nr 22, s. 7779-7784Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the further development of reactive sputter deposition, strategies which allow for stabilization of the transition zone between the metallic and compound modes, elimination of the process hysteresis, and increase of the deposition rate, are of particular interest. In this study, the hysteresis behavior and the characteristics of the transition zone during reactive high power impulse magnetron sputtering (HiPIMS) of Al and Ce targets in an Ar-O(2) atmosphere as a function of the pulsing frequency and the pumping speed are investigated. Comparison with reactive direct current magnetron sputtering (DCMS) reveals that HiPIMS allows for elimination/suppression of the hysteresis and a smoother transition from the metallic to the compound sputtering mode. For the experimental conditions employed in the present study, optimum behavior with respect to the hysteresis width is obtained at frequency values between 2 and 4 kHz, while HiPIMS processes with values below or above this range resemble the DCMS behavior. Al-O films are deposited using both HiPIMS and DCMS. Analysis of the film properties shows that elimination/suppression of the hysteresis in HiPIMS facilitates the growth of stoichiometric and transparent Al(2)O(3) at relatively high deposition rates over a wider range of experimental conditions as compared to DCMS.

  • 153.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Kawaguchi, T.
    Miki, N.
    Tokyo Inst Technol, Dept Mech & Aerosp Engn, Tokyo, Japan..
    Azami, T.
    Tokyo Inst Technol, Dept Mech & Aerosp Engn, Tokyo, Japan..
    Sakamoto, H.
    Tokyo Inst Technol, Dept Mech & Aerosp Engn, Tokyo, Japan..
    Okuma, M.
    Tokyo Inst Technol, Dept Mech & Aerosp Engn, Tokyo, Japan..
    A Vibration Estimation Method for Wind Turbine Blades2017Inngår i: Experimental mechanics, ISSN 0014-4851, E-ISSN 1741-2765, Vol. 57, nr 8, s. 1213-1224Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper reports the development of a vibration monitoring system for wind turbine blades. This system is used to estimate the deflection at the tip blade on a wind turbine tower. Technical accidents of wind turbine blades have become increasingly common. Thus, regular monitoring of the blades is very important to prevent breakdowns, especially in cases when the blades begin to vibrate excessively. The monitoring system developed in this study satisfies two main objectives for practicality. First, our system is easy to install on existing wind turbines. Second, blade deflection is measured in real time. Our system can be operated using a few strain gages attached at the blade root, and the deflection is calculated based on the monitored stress. Thus, direct measurement of deflection at the blade tip is unnecessary. An estimation algorithm for this purpose is adopted based on the experimental modal analysis. This paper focuses on the evaluation of the estimation algorithm to investigate the feasibility of our system. Basic experiments were conducted using a simple blade model of a 300 W scaled wind turbine under rotation. Signals from the strain gages were acquired by a sensor network and sent to a computer through a wireless connection. The results show that the estimation accuracy is acceptably high. Therefore, we conclude that our proposed system is practical.

  • 154.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Uzunoglu, Bahri
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Wind Flow Resource Analysis Of Urban Structures: A Validation Study2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In order to have better insight into the physics of the urban wind turbines, a Computational Fluid Dynamics (CFD) flow solver has been developed for industrial applications by Uppsala University and SOLUTE Ingenieros. Urban wind resource assessment for small scale wind applications present several challenges and complexities for that are different from large-scale wind power generation. Urban boundary layer relevant in this regime of flows have different horizontal profiles impacted by the buildings, low speed wind regimes, separation and different turbulence characteristics. Preliminary measurement results will be presented for a particular site in Huesca Spain where a measurement campaign is undertaken to validate the CFD results.

  • 155.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Uzunoğlu, Bahri
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära. Florida State Univ, Dept Math, Tallahassee, FL, USA.
    Vortex induced vibration energy extraction modeling via forced versus free vibration2017Inngår i: Proceedings Of Oceans 2017 - Aberdeen, IEEE, 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Vortex induced vibrations (VIV) for energy extraction have been revisited in last years by both marine power and wind power communities. Even though vortex induced vibrations have been focus of research for many years, energy extraction from vortex induced vibrations is relevantly new field which needs more detailed investigation and modeling. To this end, there has been recent experimental and modeling parametric studies where VIV was modeled by solution of one-degree-of-freedom ordinary differential equation spring system where engineering modeling of vortex induced vibration for energy extraction has been investigated based on a spring system with the forces defined from forced oscillation experiments where full coupling of free oscillations were not taken into account. Herein a Computational Fluid Dynamics (CFD) modeling of a circular cylinder will be studied to compare forced and free vibrations in the context of vortex-induced energy extraction. The model is essentially solved by partial differential isothermal incompressible Navier-Stokes equations to model fully mathematical model of the fluid-structure interaction of vortex induced vibration. The comparison between forced and free oscillation response studies of this paper will serve to improve the scientific knowledge where vortex induced vibration modeling are comparatively more limited. The preliminary results are presented herein for forced and free oscillations for the Reynolds number regimes Re = 100 and Re = 3800 in two dimensions for combinations of amplitudes and frequency of oscillations in the context of energy extraction modeling.

  • 156.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Carreri, Felipe de Campos
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Sabelfeld, Alex
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Gerdes, Holger
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Bandorf, Ralf
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Kubart, Tomáš
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bräuer, Günter
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Industrial Scale Deposition of Diamond-like Carbon Thin Films using Ne-based HiPIMS Discharge2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    High power impulse magnetron sputtering (HiPIMS) has been successful in providing highly ionized deposition fluxes for most common metals (Cu, Al, Ti). However, it is challenged when non-metals such as carbon is considered. Highly ionized carbon fluxes (up to 100%) are essential for the synthesis of diamond-like carbon and tetrahedral amorphous carbon thin films. Earlier reports have shown that the C+/C0 ratio in HiPIMS does not exceed 5% and film densities and sp3/sp2 bond fractions are substantially lower than those achieved using ionized physical vapour deposition based methods such as filtered cathodic vacuum arc and pulsed laser deposition. In our previous work, we demonstrated that Ne-based HiPIMS discharge entails energetic electrons as compared to Ar-based HiPIMS discharge facilitating the generation of highly ionized C fluxes as well as diamond-like carbon thin films with mass densities in the order of 2.8 g/cm3

    In this work, we perform industrial scale deposition of diamond-like carbon thin films using Ne- as well as Ar-based HiPIMS discharge. In order to investigate the effect of electron temperature enhancement and its correlation to generation of C1+ ion fluxes in Ne-based HiPIMS discharge, we perform time-averaged and time-resolved measurements of electron temperature as well as ion density at the substrate position using a flat probe. We also investigate the effect of plasma properties on the ionization of sputtered C as well as buffer gas species by measuring the optical emission from the discharge. In order to correlate the plasma and film properties, we synthesize C thin films under energetic deposition conditions and investigate structural (mass density, sp3/sp2 bond fraction, H content) and mechanical (hardness, elastic modulus, adhesion strength) properties of the resulting diamond-like carbon thin films.

  • 157.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ferreira, Fabio
    Univ Coimbra, SEG CEMMPRE Dept Mech Engn, Rua Luis Reis Santos, P-3030788 Coimbra, Portugal.
    Oliveira, Joao
    Univ Coimbra, SEG CEMMPRE Dept Mech Engn, Rua Luis Reis Santos, P-3030788 Coimbra, Portugal.
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Mechanical Properties of Hydrogen Free Diamond-Like Carbon Thin Films Deposited by High Power Impulse Magnetron Sputtering with Ne2018Inngår i: Coatings, ISSN 2079-6412, Vol. 8, nr 11, artikkel-id 385Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydrogen-free diamond-like carbon (DLC) thin films are attractive for a wide range of industrial applications. One of the challenges related to the use of hard DLC lies in the high intrinsic compressive stresses that limit the film adhesion. Here, we report on the mechanical and tribological properties of DLC films deposited by High Power Impulse Magnetron Sputtering (HiPIMS) with Ne as the process gas. In contrast to standard magnetron sputtering as well as standard Ar-based HiPIMS process, the Ne-HiPIMS lead to dense DLC films with increased mass density (up to 2.65 g/cm(3)) and a hardness of 23 GPa when deposited on steel with a Cr + CrN adhesion interlayer. Tribological testing by the pin-on-disk method revealed a friction coefficient of 0.22 against steel and a wear rate of 2 x 10(-17) m(3)/Nm. The wear rate is about an order of magnitude lower than that of the films deposited using Ar. The differences in the film properties are attributed to an enhanced C ionization in the Ne-HiPIMS discharge.

  • 158.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ji, Yu-Xia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kubart, Tomás
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Low-temperature synthesis of thermochromic vanadium dioxide thin films using reactive magnetron sputtering2015Inngår i: Abstracts, 2015Konferansepaper (Fagfellevurdert)
  • 159.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ji, Yu-Xia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Montero, Jose
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kubart, Tomáš
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Deposition of thermochromic vanadium dioxide thin films by reactive high power impulse magnetron sputtering2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Vanadium dioxide exhibits a reversible phase transition from semiconducting state (monoclinic structure) to a metallic state (tetragonal structure) at ~68 oC. This so-called metal-insulator transition (MIT) entails thermochromic behavior manifested by large changes in optical properties, such as high infrared transmittance modulation in thin films, thereby making VO2-based films a suitable candidate for optical switching applications such as self-tunable infrared filters. Thermochromic VO2 thin films have been widely investigated for optical applications, but high growth temperatures (> 400 oC) required for synthesizing crystalline VO2 thin films, high MIT temperature (68 oC) as well as low visible transmittance (typically ~50%) limit their applicability for example for energy efficient smart windows.

     

    Synthesis of metal-oxide thin films using highly ionized vapor fluxes has been shown to facilitate low-temperature film growth as well as control over phase formation and resulting film properties. In the present work, we synthesize VO2 thin films by use of highly ionized vapor fluxes that are generated by high power impulse magnetron sputtering (HiPIMS). In order to establish a correlation between the plasma and film properties, we investigate the discharge characteristics by analyzing the discharge current-voltage characteristics under varied process parameters such as peak-power, pulse-width and gas phase composition and grow VO2 thin films under suitable process conditions. We investigate the effect of growth temperature (room temperature to 500 oC), energy of the deposition flux (controlled by substrate bias potential) and type of substrate (Si, glass, ITO-coated glass) on crystallinity, phase formation and on optical properties (visible transmittance and infrared modulation) of the resulting thin films. For reference, the discharge characteristics and properties of films deposited by pulsed direct current magnetron sputtering are also studied.         

  • 160.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ji, Yu-Xia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Montero, Jose
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Low-temperature synthesis of thermochromic vanadium dioxide thin films by reactive high power impulse magnetron sputtering2016Inngår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 149, s. 137-144Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermochromic (TC) vanadium dioxide thin films provide means for controlling solar energy throughput and can be used for energy-saving applications such as smart windows. One of the factors limiting the deployment of VO2 films in TC devices is the growth temperature tau(s). At present, temperatures in excess of 450 degrees C are required, which clearly can be an impediment especially for temperature-sensitive substrates. Here we address the issue of high tau(s) by synthesizing VO2 thin films from highly ionized fluxes of depositing species generated in high power impulse magnetron sputtering (HiPIMS) discharges. The use of ions facilitates low-temperature film growth because the energy of the depositing species can be readily manipulated by substrate bias. For comparison, films were also synthesized by pulsed direct current magnetron sputtering. Structural and optical characterization of VO2 thin films on ITO-coated glass substrates confirms previous results that HiPIMS allows tau(s) to be reduced from 500 to 300 degrees C. Importantly, we demonstrated that HiPIMS permits the composition and TC response of the films to be tuned by altering the energy of the deposition flux via substrate bias. An optimum ion energy of 100 eV was identified, which points at a potential for further reduction of tau(s) thereby opening new possibilities for industrially-relevant applications of VO2-based TC thin films. Weak TC activity was observed even at tau(s) approximate to 200 degrees C in HiPIMS-produced films.

  • 161.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ion induced stress relaxation in dense sputter-deposited DLC thin films2017Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 111, nr 5, artikkel-id 051902Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Deposition of high-density and low-stress hydrogen-free diamond like carbon (DLC) thin films is demonstrated using a pulsed ionized sputtering process. This process is based on high power impulse magnetron sputtering, and high C ionization is achieved using Ne as the sputtering gas. The intrinsic compressive stress and its evolution with respect to ion energy and ion flux are explained in terms of the compressive stress based subplantation model for DLC growth by Davis. The highest mass density was similar to 2.7 g/cm(3), and the compressive stresses did not exceed similar to 2.5 GPa. The resulting film stresses are substantially lower than those achieved for the films exhibiting similar mass densities grown by filtered cathodic vacuum arc and pulsed laser deposition methods. This unique combination of high mass density and low compressive stress is attributed to the ion induced stress relaxation during the pulse-off time which corresponds to the post thermal spike relaxation timescales. We therefore propose that the temporal ion flux variations determine the magnitude of the compressive stress observed in our films. Published by AIP Publishing.

  • 162.
    Aijaz, Asim
    et al.
    Linkoping Univ, Dept Phys Chem & Biol, IFM Mat Phys, SE-58183 Linkoping, Sweden.;Uppsala Univ, Dept Engn Sci, Angstrom Lab, POB 534, SE-75121 Uppsala, Sweden..
    Louring, Sascha
    Aarhus Univ, Interdisciplinary Nanosci Ctr iNANO, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.;Danish Technol Inst, Tribol Ctr, Teknol Pk,Kongsvang Alle 29, DK-8000 Aarhus C, Denmark..
    Lundin, Daniel
    Univ Paris Saclay, Univ Paris Sud, LPGP, CNRS,UMR 8578, F-91405 Orsay, France..
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Jensen, Jens
    Linkoping Univ, Dept Phys Chem & Biol, IFM Mat Phys, SE-58183 Linkoping, Sweden..
    Sarakinos, Kostas
    Linkoping Univ, Dept Phys Chem & Biol, IFM Mat Phys, SE-58183 Linkoping, Sweden..
    Helmersson, Ulf
    Linkoping Univ, Dept Phys Chem & Biol, IFM Mat Phys, SE-58183 Linkoping, Sweden..
    Synthesis of hydrogenated diamondlike carbon thin films using neon-acetylene based high power impulse magnetron sputtering discharges2016Inngår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 34, nr 6, artikkel-id 061504Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydrogenated diamondlike carbon (DLC:H) thin films exhibit many interesting properties that can be tailored by controlling the composition and energy of the vapor fluxes used for their synthesis. This control can be facilitated by high electron density and/or high electron temperature plasmas that allow one to effectively tune the gas and surface chemistry during film growth, as well as the degree of ionization of the film forming species. The authors have recently demonstrated by adding Ne in an Ar-C high power impulse magnetron sputtering (HiPIMS) discharge that electron temperatures can be effectively increased to substantially ionize C species [Aijaz et al., Diamond Relat. Mater. 23, 1 (2012)]. The authors also developed an Ar-C2H2 HiPIMS process in which the high electron densities provided by the HiPIMS operation mode enhance gas phase dissociation reactions enabling control of the plasma and growth chemistry [Aijaz et al., Diamond Relat. Mater. 44, 117 (2014)]. Seeking to further enhance electron temperature and thereby promote electron impact induced interactions, control plasma chemical reaction pathways, and tune the resulting film properties, in this work, the authors synthesize DLC: H thin films by admixing Ne in a HiPIMS based Ar/C2H2 discharge. The authors investigate the plasma properties and discharge characteristics by measuring electron energy distributions as well as by studying discharge current characteristics showing an electron temperature enhancement in C2H2 based discharges and the role of ionic contribution to the film growth. These discharge conditions allow for the growth of thick (>1 mu m) DLC: H thin films exhibiting low compressive stresses (similar to 0.5 GPa), high hardness (similar to 25 GPa), low H content (similar to 11%), and density in the order of 2.2 g/cm(3). The authors also show that film densification and change of mechanical properties are related to H removal by ion bombardment rather than subplantation.

  • 163.
    Aiso, Toshiharu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Workpiece steels protecting cutting tools from wear: A study of the effects of alloying elements on material transfer and coating damage mechanisms2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The vision of this thesis is to improve the machinability of workpiece steels. Workpiece material frequently transfers to the cutting tools during machining, and the transfer layers then forming on the tools may give both good and bad effects on machining performance and tool life. The objective of this work is to understand the effects of alloying element additions to workpiece steels on material transfer and the roles of the formed transfer layers on friction characteristics and wear of tools.

    To isolate and study the influence of the individual alloying elements, model steels are specifically designed. These steels include one reference with C as the only alloying element and others alloyed also with single additions or combined additions of 1 mass% Si, Mn, Cr and Al. The experiments are performed using both a sliding test, simulating the material transfer in milling, and a turning test.

    In a sliding contact, the mode of transfer is strongly dependent on the normal load and sliding speed. Material transfer initiates extremely fast, in less than 0.025 s, and characteristic transfer layers develop during the first few seconds. The different steel compositions result in the formation of different types of oxides in the transfer layers. At the workpiece/tool interface where the conditions involve high temperature, high pressure and low oxygen supply, easily oxidized alloying elements in the steel are preferentially transferred, enriched and form a stable oxide on the tool surface. The degree of enrichment of the alloying elements in the oxides is strongly related to their tendencies to become oxidized.

    The difference in melting temperature of the oxides, and thus the tendency to soften during sliding, explains the difference in the resulting friction coefficient. The widest differences in friction coefficients are found between the Si and Al additions. A Si containing oxide shows the lowest friction and an Al containing oxide the highest.

    The damage mechanism of coated tools is chiefly influenced by the form and shear strength of the transferred material. Absence of transfer layer or non-continuous transferred material leads to continuous wear of the coating. Contrastingly, continuous transfer layers protect it from wear. However, transfer layers with very high shear strength result in high friction heat and a large amount of steel transfer. This leads to rapid coating cracking or adhesive wear.

    Delarbeid
    1. Influence of contact parameters on material transfer from steel to TiN coated tool – optimisation of a sliding test for simulation of material transfer in milling
    Åpne denne publikasjonen i ny fane eller vindu >>Influence of contact parameters on material transfer from steel to TiN coated tool – optimisation of a sliding test for simulation of material transfer in milling
    2016 (engelsk)Inngår i: Tribology - Materials, Surfaces & Interfaces, ISSN 1751-5831, E-ISSN 1751-584X, Vol. 10, nr 3, s. 107-116Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Sliding between crossed cylinders, one large work material cylinder and one smaller coated tool cylinder, can be used to simulate the contact between a chip and the rake face of a cutting tool. However accurate simulations require the mode of material transfer in the test to match that in real machining. The mode is strongly dependent on normal load and sliding speed, and it is classified into four types; negligible oxide, only iron oxide, iron oxide and alloy oxide, and metallic transfer with coating cracking. A high load proved to be most important to accurately simulate the mode and area of material transfer occurring in milling. The diameter of the work material cylinder influences the shape of the contact mark, but has no influence on the mode of transfer. This means smaller work material diameters can favorably be used, reducing costs and facilitating handling during both tests and analysis.

    Emneord
    Sliding test, Material transfer, Milling, Coating
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot tribomaterial
    Identifikatorer
    urn:nbn:se:uu:diva-299592 (URN)10.1080/17515831.2016.1202548 (DOI)
    Tilgjengelig fra: 2016-07-23 Laget: 2016-07-23 Sist oppdatert: 2017-11-28
    2. Effect of Si and Cr additions to carbon steel on material transfer in a steel/TiN coated tool sliding contact
    Åpne denne publikasjonen i ny fane eller vindu >>Effect of Si and Cr additions to carbon steel on material transfer in a steel/TiN coated tool sliding contact
    2016 (engelsk)Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 97, s. 337-348Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A crossed cylinders sliding test, simulating the contact between the chip and the tool in machining, is used to evaluate material transfer and friction characteristics of a TiN coating against specifically designed model steels. These include one base reference, only alloyed with C (Base steel) and two alloyed also with 1 mass% Si or Cr. When sliding against the Base steel, an Fe-O layer is formed on the coating. Against the Si and Cr alloyed steels, Fe-Si-O and Fe-Cr-O layers are formed. In these oxides, Si and Cr are enriched, i.e. preferentially transferred from the steels. Compared to the Base steel, the friction coefficient is significantly lower against the Si alloyed steel and higher against the Cr alloyed steel.

    Emneord
    Transfer, Coating, Sliding
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot tribomaterial
    Identifikatorer
    urn:nbn:se:uu:diva-284092 (URN)10.1016/j.triboint.2016.01.032 (DOI)000374194900035 ()
    Tilgjengelig fra: 2016-04-15 Laget: 2016-04-15 Sist oppdatert: 2017-11-30bibliografisk kontrollert
    3. Influence of Mn and Al additions to carbon steel on material transfer and coating damage mechanism in a sliding contact between steel and TiN coated HSS tool
    Åpne denne publikasjonen i ny fane eller vindu >>Influence of Mn and Al additions to carbon steel on material transfer and coating damage mechanism in a sliding contact between steel and TiN coated HSS tool
    2016 (engelsk)Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 101, s. 414-424Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A crossed cylinders sliding test, simulating the contact between the chip and the cutting tool, is used to evaluate material transfer, friction characteristics and coating damage of a TiN coated high speed steel against specifically designed model steels. These steels include one reference with C as the only alloy element (Base steel), and two alloyed also with 1 mass% Mn or Al. When sliding against the Base steel, an Fe–O layer forms on the coating and protects it from wear. Against the Mn alloyed steel, Fe–Mn–O forms, which has no protective effect. Against the Al alloyed steel, an almost pure Al–O layer forms. This leads to the highest friction, rapidly causing substrate softening and coating fracture.

    Emneord
    Transfer, Coating, Sliding
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot tribomaterial
    Identifikatorer
    urn:nbn:se:uu:diva-294613 (URN)10.1016/j.triboint.2016.04.036 (DOI)000379563700044 ()
    Tilgjengelig fra: 2016-05-25 Laget: 2016-05-25 Sist oppdatert: 2018-01-10bibliografisk kontrollert
    4. Effect of combined additions of Si, Mn, Cr and Al to carbon steel on material transfer in a steel/TiN coated tool sliding contact
    Åpne denne publikasjonen i ny fane eller vindu >>Effect of combined additions of Si, Mn, Cr and Al to carbon steel on material transfer in a steel/TiN coated tool sliding contact
    2017 (engelsk)Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 388-389, s. 9-17Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Material transferred from steel work materials onto the cutting tools largely affects tool life and machining performance. This material transfer is strongly influenced by the steel composition, and different alloying can have very different effects. Crossed cylinders sliding tests can be used to simulate the contact between the chip and the tool in machining. In this work such a test is used to evaluate material transfer and friction characteristics of a TiN coated tool sliding against five model steels. These model steels are especially designed to study the effects from specific combination of alloy elements, i.e. the steels, containing 0.55 mass% C and 1 mass% Si, are alloyed with one or more of 1 mass% Mn, Cr and Al. When using the steels alloyed without Al, Si-rich oxide layers are formed on the coating, resulting in a low friction coefficient. When using the steels alloyed with Al, almost pure Al–O layers are formed, resulting in a higher friction coefficient and rapid coating cracking. Essentially, the most easily oxidized alloy element is most strongly enriched in the oxide and decides the main mechanism of the material transfer and friction behavior.

    Emneord
    Sliding, Steel, PVD coatings, Cutting tools, Transfer
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot tribomaterial
    Identifikatorer
    urn:nbn:se:uu:diva-306189 (URN)10.1016/j.wear.2017.04.028 (DOI)000412614900003 ()
    Konferanse
    NORDTRIB 2016: The 17th Nordic Symposium on Tribology,14th - 17th June 2016 - Aulanko, Hämeenlinna, Finland
    Tilgjengelig fra: 2016-10-26 Laget: 2016-10-26 Sist oppdatert: 2017-12-22bibliografisk kontrollert
    5. Effect of Si and Al additions to carbon steel on material transfer and coating damage mechanism in turning with CVD coated tools
    Åpne denne publikasjonen i ny fane eller vindu >>Effect of Si and Al additions to carbon steel on material transfer and coating damage mechanism in turning with CVD coated tools
    2016 (engelsk)Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 368-369, s. 379-389Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Material transfer from the work materials to the tools strongly influences machining performance and tool life. The influence of Si and Al additions to carbon steel on the material transfer and coating wear in turning with CVD coated carbide tools is investigated. Three model steels are specifically designed to separately study the effects of the individual alloying elements: one reference steel with C as the only alloying element (Base steel), and two steels alloyed also with 1 mass% Si or Al. In the region around the depth of cut on the rake face, where the outside edge of the chip passes over the tool surface, the coating is worn mainly by abrasion when cutting the Base steel. When cutting the Si alloyed steel, an almost pure Si–O transfer layer covers the coating surface, which protects it from wear. When cutting the Al alloyed steel, an almost pure Al–O transfer layer forms on the coating. This layer promotes steel transfer and associated adhesive wear of the coating, which rapidly results in coating detachment and eventually causes notch wear. In the crater region, only the Al alloyed steel results in a transfer layer, an AlN layer that reduces the crater wear.

    Emneord
    Steel, CVD coatings, Cutting tools, Transfer
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot tribomaterial
    Identifikatorer
    urn:nbn:se:uu:diva-306187 (URN)10.1016/j.wear.2016.10.011 (DOI)000390733400041 ()
    Tilgjengelig fra: 2016-10-26 Laget: 2016-10-26 Sist oppdatert: 2017-08-08bibliografisk kontrollert
  • 164.
    Aiso, Toshiharu
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence of contact parameters on material transfer from steel to TiN coated tool – optimisation of a sliding test for simulation of material transfer in milling2016Inngår i: Tribology - Materials, Surfaces & Interfaces, ISSN 1751-5831, E-ISSN 1751-584X, Vol. 10, nr 3, s. 107-116Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sliding between crossed cylinders, one large work material cylinder and one smaller coated tool cylinder, can be used to simulate the contact between a chip and the rake face of a cutting tool. However accurate simulations require the mode of material transfer in the test to match that in real machining. The mode is strongly dependent on normal load and sliding speed, and it is classified into four types; negligible oxide, only iron oxide, iron oxide and alloy oxide, and metallic transfer with coating cracking. A high load proved to be most important to accurately simulate the mode and area of material transfer occurring in milling. The diameter of the work material cylinder influences the shape of the contact mark, but has no influence on the mode of transfer. This means smaller work material diameters can favorably be used, reducing costs and facilitating handling during both tests and analysis.

  • 165.
    Aiso, Toshiharu
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Kubota, Manabu
    Nippon Steel & Sumitomo Metal Corporation.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Effect of combined additions of Si, Mn, Cr and Al to carbon steel on material transfer in a steel/TiN coated tool sliding contact2017Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 388-389, s. 9-17Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Material transferred from steel work materials onto the cutting tools largely affects tool life and machining performance. This material transfer is strongly influenced by the steel composition, and different alloying can have very different effects. Crossed cylinders sliding tests can be used to simulate the contact between the chip and the tool in machining. In this work such a test is used to evaluate material transfer and friction characteristics of a TiN coated tool sliding against five model steels. These model steels are especially designed to study the effects from specific combination of alloy elements, i.e. the steels, containing 0.55 mass% C and 1 mass% Si, are alloyed with one or more of 1 mass% Mn, Cr and Al. When using the steels alloyed without Al, Si-rich oxide layers are formed on the coating, resulting in a low friction coefficient. When using the steels alloyed with Al, almost pure Al–O layers are formed, resulting in a higher friction coefficient and rapid coating cracking. Essentially, the most easily oxidized alloy element is most strongly enriched in the oxide and decides the main mechanism of the material transfer and friction behavior.

  • 166.
    Aiso, Toshiharu
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Kubota, Manabu
    Nippon Steel & Sumitomo Metal Corporation.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Effect of Si and Al additions to carbon steel on material transfer and coating damage mechanism in turning with CVD coated tools2016Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 368-369, s. 379-389Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Material transfer from the work materials to the tools strongly influences machining performance and tool life. The influence of Si and Al additions to carbon steel on the material transfer and coating wear in turning with CVD coated carbide tools is investigated. Three model steels are specifically designed to separately study the effects of the individual alloying elements: one reference steel with C as the only alloying element (Base steel), and two steels alloyed also with 1 mass% Si or Al. In the region around the depth of cut on the rake face, where the outside edge of the chip passes over the tool surface, the coating is worn mainly by abrasion when cutting the Base steel. When cutting the Si alloyed steel, an almost pure Si–O transfer layer covers the coating surface, which protects it from wear. When cutting the Al alloyed steel, an almost pure Al–O transfer layer forms on the coating. This layer promotes steel transfer and associated adhesive wear of the coating, which rapidly results in coating detachment and eventually causes notch wear. In the crater region, only the Al alloyed steel results in a transfer layer, an AlN layer that reduces the crater wear.

  • 167.
    Aiso, Toshiharu
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Kubota, Manabu
    Nippon Steel & Sumitomo Metal Corporation.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Effect of Si and Cr additions to carbon steel on material transfer in a steel/TiN coated tool sliding contact2016Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 97, s. 337-348Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A crossed cylinders sliding test, simulating the contact between the chip and the tool in machining, is used to evaluate material transfer and friction characteristics of a TiN coating against specifically designed model steels. These include one base reference, only alloyed with C (Base steel) and two alloyed also with 1 mass% Si or Cr. When sliding against the Base steel, an Fe-O layer is formed on the coating. Against the Si and Cr alloyed steels, Fe-Si-O and Fe-Cr-O layers are formed. In these oxides, Si and Cr are enriched, i.e. preferentially transferred from the steels. Compared to the Base steel, the friction coefficient is significantly lower against the Si alloyed steel and higher against the Cr alloyed steel.

  • 168.
    Aiso, Toshiharu
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Kubota, Manabu
    Nippon Steel & Sumitomo Metal Corporation.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence of Mn and Al additions to carbon steel on material transfer and coating damage mechanism in a sliding contact between steel and TiN coated HSS tool2016Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 101, s. 414-424Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A crossed cylinders sliding test, simulating the contact between the chip and the cutting tool, is used to evaluate material transfer, friction characteristics and coating damage of a TiN coated high speed steel against specifically designed model steels. These steels include one reference with C as the only alloy element (Base steel), and two alloyed also with 1 mass% Mn or Al. When sliding against the Base steel, an Fe–O layer forms on the coating and protects it from wear. Against the Mn alloyed steel, Fe–Mn–O forms, which has no protective effect. Against the Al alloyed steel, an almost pure Al–O layer forms. This leads to the highest friction, rapidly causing substrate softening and coating fracture.

  • 169.
    Ajalloueian, Fatemeh
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Tavanai, Hossein
    Hilborn, Jons
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Donzel-Gargand, Olivier
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Leifer, Klaus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wickham, Abeni
    Arpanaei, Ayyoob
    Emulsion Electrospinning as an Approach to Fabricate PLGA/Chitosan Nanofibers for Biomedical Applications2014Inngår i: BioMed Research International, ISSN 2314-6133, Vol. 2014, s. 475280-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Novel nanofibers from blends of polylactic-co-glycolic acid (PLGA) and chitosan have been produced through an emulsion electrospinning process. The spinning solution employed polyvinyl alcohol (PVA) as the emulsifier. PVA was extracted from the electrospun nanofibers, resulting in a final scaffold consisting of a blend of PLGA and chitosan. The fraction of chitosan in the final electrospun mat was adjusted from 0 to 33%. Analyses by scanning and transmission electron microscopy show uniform nanofibers with homogenous distribution of PLGA and chitosan in their cross section. Infrared spectroscopy verifies that electrospun mats contain both PLGA and chitosan. Moreover, contact angle measurements show that the electrospun PLGA/chitosanmats are more hydrophilic than electrospun mats of pure PLGA. Tensile strengths of 4.94 MPa and 4.21 MPa for PLGA/chitosan in dry and wet conditions, respectively, illustrate that the polyblend mats of PLGA/chitosan are strong enough for many biomedical applications. Cell culture studies suggest that PLGA/chitosan nanofibers promote fibroblast attachment and proliferation compared to PLGA membranes. It can be assumed that the nanofibrous composite scaffold of PLGA/chitosan could be potentially used for skin tissue reconstruction.

  • 170.
    Ajamlou, Robin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nyman, Emma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Provisorisk takbelysning vid byggarbetsplatser: En studie av belysningens funktion och dess påverkan på yrkesarbetaren2018Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    This report explores the definitions of general- and work lighting in an indoor construction site and how the lighting affects a construction worker. This in order to clarify the controversial topic of: which purpose the ceiling lighting has, thus making the lighting plan optimal. This study was made in cooperation with Skanska Sweden AB. The main ceiling lighting-device in Skanska Sweden is a custom made LED-lamp which is the main tool that this research is based on. The main research methods are project site visits, interviews and surveys in combination with literature studies, and also practical measurements and simulations of the LED-lamps. The results of the interviews and surveys show that comprehension of the functions of the ceiling lighting varies among Skanska Sweden employees. While construction workers generally refer to work lighting when addressing ceiling lighting, the managers tend to refer to general lighting or as a tool to orientate the building. Although, how general lighting is defined, varies among the employees. With that said, the simulations reveal that a reasonable amount of a ceiling lighting will not fulfil the requirements for work lighting for all construction operations. Furthermore, our results from the interviews and surveys confirm those from previous studies; that lighting is essential for the well-being of people. A poorly illuminated workspace dulls one’s work performance and effects one’s health in both the short- and long terms. A well-lit workspace can, on the other hand, reduce the potential health and safety risks on a construction site and also ease multiple work tasks. There are currently no clear assembling routines of ceiling lighting. Therefore, to create consensus on the purpose of lighting and the health and safety prospects that come with it, this report recommends possible solutions and clarifications of the issues and misinterpretations in the matter.

  • 171.
    Ajaxon, Ingrid
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Can Bone Void Fillers Carry Load?: Behaviour of Calcium Phosphate Cements Under Different Loading Scenarios2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Calcium phosphate cements (CPCs) are used as bone void fillers and as complements to hardware in fracture fixation. The aim of this thesis was to investigate the possibilities and limitations of the CPCs’ mechanical properties, and find out if these ceramic bone cements can carry application-specific loads, alone or as part of a construct. Recently developed experimental brushite and apatite cements were found to have a significantly higher strength in compression, tension and flexion compared to the commercially available CPCs chronOS™ Inject and Norian® SRS®. By using a high-resolution measurement technique the elastic moduli of the CPCs were determined and found to be at least twice as high compared to earlier measurements, and closer to cortical bone than trabecular bone. Using the same method, Poisson's ratio for pure CPCs was determined for the first time. A non-destructive porosity measurement method for wet brushite cements was developed, and subsequently used to study the porosity increase during in vitro degradation. The compressive strength of the experimental brushite cement was still higher than that of trabecular bone after 25 weeks of degradation, showing that the cement can carry high loads over a time span sufficiently long for a fracture to heal. This thesis also presents the first ever fatigue results for acidic CPCs, and confirms the importance of testing the materials under cyclic loading as the cements may fail at stress levels much lower than the material’s quasi-static compressive strength. A decrease in fatigue life was found for brushite cements containing higher amounts of monetite. Increasing porosity and testing in a physiological buffer solution (PBS), rather than air, also decreased the fatigue life. However, the experimental brushite cement had a high probability of surviving loads found in the spine when tested in PBS, which has previously never been accomplished for acidic CPCs. In conclusion, available brushite cements may be able to carry the load alone in scenarios where the cortical shell is intact, the loading is mainly compressive, and the expected maximum stress is below 10 MPa. Under such circumstances this CPC may be the preferred choice over less biocompatible and non-degradable materials.

    Delarbeid
    1. Mechanical Properties of Brushite Calcium Phosphate Cements
    Åpne denne publikasjonen i ny fane eller vindu >>Mechanical Properties of Brushite Calcium Phosphate Cements
    2017 (engelsk)Inngår i: The World Scientific Encyclopedia of Nanomedicine and Bioengineering II: Bioimplants, Regenerative Medicine, and Nano-Cancer Diagnosis and Phototherapy: Volume 3: Design of Bioactive Materials for Bone Repair and Regeneration / [ed] Shi, D., Singapore: World Scientific Pte Ltd. , 2017Kapittel i bok, del av antologi (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Singapore: World Scientific Pte Ltd., 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-316712 (URN)978-981-4667-58-6 (ISBN)
    Forskningsfinansiär
    Swedish Research Council, GA 621-2011-6258
    Tilgjengelig fra: 2017-03-22 Laget: 2017-03-22 Sist oppdatert: 2017-03-22
    2. Compressive, diametral tensile and biaxial flexural strength of cutting-edge calcium phosphate cements
    Åpne denne publikasjonen i ny fane eller vindu >>Compressive, diametral tensile and biaxial flexural strength of cutting-edge calcium phosphate cements
    Vise andre…
    2016 (engelsk)Inngår i: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 60, s. 617-627Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Calcium phosphate cements (CPCs) are widely used in bone repair. Currently there are two main types of CPCs, brushite and apatite. The aim of this project was to evaluate the mechanical properties of particularly promising experimental brushite and apatite formulations in comparison to commercially available brushite- and apatite-based cements (chronOS Inject and Norian® SRS®, respectively), and in particular evaluate the diametral tensile strength and biaxial flexural strength of these cements in both wet and dry conditions for the first time. The cements׳ porosity and their compressive, diametral tensile and biaxial flexural strength were tested in wet (or moist) and dry conditions. The surface morphology was characterized by scanning electron microscopy. Phase composition was assessed with X-ray diffraction. It was found that the novel experimental cements showed better mechanical properties than the commercially available cements, in all loading scenarios. The highest compressive strength (57.2±6.5 MPa before drying and 69.5±6.0 MPa after drying) was found for the experimental brushite cement. This cement also showed the highest wet diametral tensile strength (10.0±0.8 MPa) and wet biaxial flexural strength (30.7±1.8 MPa). It was also the cement that presented the lowest porosity (approx. 12%). The influence of water content was found to depend on cement type, with some cements showing higher mechanical properties after drying and some no difference after drying.

    Emneord
    Calcium phosphate cement; Brushite; Apatite; Compressive strength; Tensile strength; Flexural strength
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-284218 (URN)10.1016/j.jmbbm.2016.03.028 (DOI)000378969100055 ()27082025 (PubMedID)
    Forskningsfinansiär
    The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), IG2011-2047Swedish Research Council, 621-2011-6258
    Tilgjengelig fra: 2016-04-15 Laget: 2016-04-15 Sist oppdatert: 2018-08-10bibliografisk kontrollert
    3. Elastic properties and strain-to-crack-initation of calcium phosphate bone cements: Revelations of a high-resolution measurement technique
    Åpne denne publikasjonen i ny fane eller vindu >>Elastic properties and strain-to-crack-initation of calcium phosphate bone cements: Revelations of a high-resolution measurement technique
    Vise andre…
    2017 (engelsk)Inngår i: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 74, s. 428-437Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Calcium phosphate cements (CPCs) should ideally have mechanical properties similar to those of the bone tissue the material is used to replace or repair. Usually, the compressive strength of the CPCs is reported and, more rarely, the elastic modulus. Conversely, scarce or no data are available on Poisson's ratio and strain-to-crack-initiation. This is unfortunate, as data on the elastic response is key to, e.g., numerical model accuracy. In this study, the compressive behaviour of brushite, monetite and apatite cements was fully characterised. Measurement of the surface strains was done using a digital image correlation (DIC) technique, and compared to results obtained with the commonly used built-in displacement measurement of the materials testers. The collected data showed that the use of fixed compression platens, as opposed to spherically seated ones, may in some cases underestimate the compressive strength by up to 40%. Also, the built-in measurements may underestimate the elastic modulus by up to 62% as compared to DIC measurements. Using DIC, the brushite cement was found to be much stiffer (24.3 ± 2.3 GPa) than the apatite (13.5 ± 1.6 GPa) and monetite (7.1 ± 1.0 GPa) cements, and elastic moduli were inversely related to the porosity of the materials. Poisson's ratio was determined to be 0.26 ± 0.02 for brushite, 0.21 ± 0.02 for apatite and 0.20 ± 0.03 for monetite. All investigated CPCs showed low strain-to-crack-initiation (0.17–0.19%). In summary, the elastic modulus of CPCs is substantially higher than previously reported and it is concluded that an accurate procedure is a prerequisite in order to properly compare the mechanical properties of different CPC formulations. It is recommended to use spherically seated platens and measuring the strain at a relevant resolution and on the specimen surface.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-316718 (URN)10.1016/j.jmbbm.2017.06.023 (DOI)000410253500046 ()28735216 (PubMedID)
    Forskningsfinansiär
    The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), IG2011-2047Swedish Research Council, 621-2011-6258
    Tilgjengelig fra: 2017-03-22 Laget: 2017-03-22 Sist oppdatert: 2017-12-04bibliografisk kontrollert
    4. Evaluation of a porosity measurement method for wet calcium phosphate cements
    Åpne denne publikasjonen i ny fane eller vindu >>Evaluation of a porosity measurement method for wet calcium phosphate cements
    Vise andre…
    2015 (engelsk)Inngår i: Journal of biomaterials applications, ISSN 0885-3282, E-ISSN 1530-8022, Vol. 30, nr 5, s. 526-536Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The porosity of a calcium phosphate cement is a key parameter as it affects several important properties of the cement. However, a successful, non-destructive porosity measurement method that does not include drying has not yet been reported for calcium phosphate cements. The aim of this study was to evaluate isopropanol solvent exchange as such a method. Two different types of calcium phosphate cements were used, one basic (hydroxyapatite) and one acidic (brushite). The cements were allowed to set in an aqueous environment and then immersed in isopropanol and stored under three different conditions: at room temperature, at room temperature under vacuum (300 mbar) or at 37􏰀C. The specimen mass was monitored regularly. Solvent exchange took much longer time to reach steady state in hydroxyapatite cements compared to brushite cements, 350 and 18 h, respectively. Furthermore, the immersion affected the quasi-static compressive strength of the hydroxyapatite cements. However, the strength and phase composition of the brushite cements were not affected by isopropanol immersion, suggesting that isopropanol solvent exchange can be used for brushite calcium phosphate cements. The main advantages with this method are that it is non-destructive, fast, easy and the porosity can be evaluated while the cements remain wet, allowing for further analysis on the same specimen. 

    sted, utgiver, år, opplag, sider
    Sage Publications, 2015
    Emneord
    Calcium phosphate, bone cement, porosity, solvent exchange, brushite, hydroxyapatite
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-258636 (URN)10.1177/0885328215594293 (DOI)000367743900003 ()26163278 (PubMedID)
    Forskningsfinansiär
    The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), IG2011-2047Swedish Research Council, 621-2011-6258
    Tilgjengelig fra: 2015-07-17 Laget: 2015-07-17 Sist oppdatert: 2017-12-04bibliografisk kontrollert
    5. Long-term in vitro degradation of a high-strength brushite cement in water, PBS, and serum solution
    Åpne denne publikasjonen i ny fane eller vindu >>Long-term in vitro degradation of a high-strength brushite cement in water, PBS, and serum solution
    2015 (engelsk)Inngår i: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, artikkel-id 575079Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Bone loss and fractures may call for the use of bone substituting materials, such as calcium phosphate cements (CPCs). CPCs can be degradable, and, to determine their limitations in terms of applications, their mechanical as well as chemical properties need to be evaluated over longer periods of time, under physiological conditions. However, there is lack of data on how the in vitro degradation affects high-strength brushite CPCs over longer periods of time, that is, longer than it takes for a bone fracture to heal. This study aimed at evaluating the long-term in vitro degradation properties of a high-strength brushite CPC in three different solutions: water, phosphate buffered saline, and a serum solution. Microcomputed tomography was used to evaluate the degradation nondestructively, complemented with gravimetric analysis. The compressive strength, chemical composition, and microstructure were also evaluated. Major changes from 10 weeks onwards were seen, in terms of formation of a porous outer layer of octacalcium phosphate on the specimens with a concomitant change in phase composition, increased porosity, decrease in object volume, and mechanical properties. This study illustrates the importance of long-term evaluation of similar cement compositions to be able to predict the material’s physical changes over a relevant time frame. 

    sted, utgiver, år, opplag, sider
    Hindawi Publishing Corporation, 2015
    Emneord
    Calcium phosphate, brushite, bone cement, degradation, in vitro, solvent exchange, compressive strength, micro-CT, porosity
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-265319 (URN)10.1155/2015/575079 (DOI)000364660000001 ()
    Forskningsfinansiär
    The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), IG2011-207Swedish Research Council, 621-2011-6258
    Tilgjengelig fra: 2015-10-27 Laget: 2015-10-27 Sist oppdatert: 2017-12-01bibliografisk kontrollert
    6. Compressive fatigue properties of an acidic calcium phosphate cement—effect of phase composition
    Åpne denne publikasjonen i ny fane eller vindu >>Compressive fatigue properties of an acidic calcium phosphate cement—effect of phase composition
    2017 (engelsk)Inngår i: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 28, nr 3, artikkel-id 41Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Calcium phosphate cements (CPCs) are synthetic bone grafting materials that can be used in fracture stabilization and to fill bone voids after, e.g., bone tumour excision. Currently there are several calcium phosphate-based formulations available, but their use is partly limited by a lack of knowledge of their mechanical properties, in particular their resistance to mechanical loading over longer periods of time. Furthermore, depending on, e.g., setting conditions, the end product of acidic CPCs may be mainly brushite or monetite, which have been found to behave differently under quasi-static loading. The objectives of this study were to evaluate the compressive fatigue properties of acidic CPCs, as well as the effect of phase composition on these properties. Hence, brushite cements stored for different lengths of time and with different amounts of monetite were investigated under quasi-static and dynamic compression. Both storage and brushite-to-monetite phase transformation was found to have a pronounced effect both on quasi-static compressive strength and fatigue performance of the cements, whereby a substantial phase transformation gave rise to a lower mechanical resistance. The brushite cements investigated in this study had the potential to survive 5 million cycles at a maximum compressive stress of 13 MPa. Given the limited amount of published data on fatigue properties of CPCs, this study provides an important insight into the compressive fatigue behaviour of such materials. 

    Emneord
    Bone cement, brushite, monetite, fatigue, mechanical properties
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-314237 (URN)10.1007/s10856-017-5851-5 (DOI)000394242700006 ()28144853 (PubMedID)
    Forskningsfinansiär
    Swedish Research Council, 621-2011-6258
    Tilgjengelig fra: 2017-02-03 Laget: 2017-01-31 Sist oppdatert: 2017-11-29bibliografisk kontrollert
    7. Compressive fatigue properties of a high-strength, degradable calcium phosphate bone cement – influence of porosity and environment
    Åpne denne publikasjonen i ny fane eller vindu >>Compressive fatigue properties of a high-strength, degradable calcium phosphate bone cement – influence of porosity and environment
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-316717 (URN)
    Forskningsfinansiär
    Swedish Research Council, 621-2011-6258
    Tilgjengelig fra: 2017-03-22 Laget: 2017-03-22 Sist oppdatert: 2017-03-22
  • 172.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Acciaioli, Alice
    Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica.
    Lionello, Giacomo
    Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica.
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia (UPC).
    Öhman, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Baleani, Massimilliano
    Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Elastic properties and strain-to-crack-initation of calcium phosphate bone cements: Revelations of a high-resolution measurement technique2017Inngår i: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 74, s. 428-437Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Calcium phosphate cements (CPCs) should ideally have mechanical properties similar to those of the bone tissue the material is used to replace or repair. Usually, the compressive strength of the CPCs is reported and, more rarely, the elastic modulus. Conversely, scarce or no data are available on Poisson's ratio and strain-to-crack-initiation. This is unfortunate, as data on the elastic response is key to, e.g., numerical model accuracy. In this study, the compressive behaviour of brushite, monetite and apatite cements was fully characterised. Measurement of the surface strains was done using a digital image correlation (DIC) technique, and compared to results obtained with the commonly used built-in displacement measurement of the materials testers. The collected data showed that the use of fixed compression platens, as opposed to spherically seated ones, may in some cases underestimate the compressive strength by up to 40%. Also, the built-in measurements may underestimate the elastic modulus by up to 62% as compared to DIC measurements. Using DIC, the brushite cement was found to be much stiffer (24.3 ± 2.3 GPa) than the apatite (13.5 ± 1.6 GPa) and monetite (7.1 ± 1.0 GPa) cements, and elastic moduli were inversely related to the porosity of the materials. Poisson's ratio was determined to be 0.26 ± 0.02 for brushite, 0.21 ± 0.02 for apatite and 0.20 ± 0.03 for monetite. All investigated CPCs showed low strain-to-crack-initiation (0.17–0.19%). In summary, the elastic modulus of CPCs is substantially higher than previously reported and it is concluded that an accurate procedure is a prerequisite in order to properly compare the mechanical properties of different CPC formulations. It is recommended to use spherically seated platens and measuring the strain at a relevant resolution and on the specimen surface.

  • 173.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Acciaioli, Alice
    Lionello, Giacomo
    Ginebra, Maria-Pau
    Öhman, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Baleani, Massimiliano
    Compressive strength increase of calcium phosphate bone cements is accompanied by a stiffness increase2016Konferansepaper (Annet vitenskapelig)
  • 174.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Holmberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Öhman, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Fatigue performance of a high-strength, degradable calcium phosphate bone cement2018Inngår i: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 79, s. 46-52Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Calcium phosphate cements (CPCs) are clinically used as injectable materials to fill bone voids and to improve hardware fixation in fracture surgery. In vivo they are dynamically loaded; nonetheless little is known about their fatigue properties. The aim of this study was to, for the first time, investigate the fatigue performance of a high strength, degradable (brushitic) CPC, and also evaluate the effect of cement porosity (by varying the liquid to powder ratio, L/P) and the environment (air at room temperature or in a phosphate buffered saline solution, PBS, at 37 degrees C) on the fatigue life. At a maximum compressive stress level of 15 MPa, the cements prepared with an L/P-ratio of 0.22 and 0.28 ml/g, corresponding to porosities of approximately 12% and 20%, had a 100% probability of survival until run-out of 5 million cycles, in air. When the maximum stress level, or the L/P-ratio, was increased, the probability of survival decreased. Testing in PBS at 37 degrees C led to more rapid failure of the specimens. However, the high-strength cement had a 100% probability of survival up to approximately 2.5 million cycles at a maximum compressive stress level of 10 MPa in PBS, which is substantially higher than some in vivo stress levels, e.g., those found in the spine. At 5 MPa in PBS, all specimens survived to run-out. The results found herein are important if clinical use of the material is to increase, as characterisation of the fatigue performance of CPCs is largely lacking from the literature.

  • 175.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Holmberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Öhman Mägi, Caroline
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Fatigue life of a brushite cement under cyclic compressive loading2017Konferansepaper (Fagfellevurdert)
  • 176.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Holmberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Öhman Mägi, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Long-term degradation of brushite cements in three different liquids2016Konferansepaper (Annet vitenskapelig)
  • 177.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Holmberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Öhman Mägi, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    The influence of porosity on the fatigue properties of brushite cement2016Inngår i: Biomaterials for tissue engineering models, 2016Konferansepaper (Annet vitenskapelig)
  • 178.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Holmberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Öhman-Mägi, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Compressive fatigue properties of a high-strength, degradable calcium phosphate bone cement – influence of porosity and environmentManuskript (preprint) (Annet vitenskapelig)
  • 179.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Lionello, Giacomo
    bLaboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    Ginebra, Maria-Pau
    cBiomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia .
    Öhman, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Baleani, Massimiliano
    bLaboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Local stiffness measurements in apatite and brushite cements2015Konferansepaper (Annet vitenskapelig)
  • 180.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Maazouz, Yassine
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia .
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia .
    Öhman, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    A non-drying porosity evaluation method for calcium phosphate cements2014Inngår i: 26th Symposium and Annual Meeting of the International Society for Ceramics in Medicine, 2014, s. 68-68