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  • 451.
    Wang, Zhaohui
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Tammela, Petter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Zhang, Peng
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Huo, Jinxing
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Ericson, Fredric
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Nyholm, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Freestanding nanocellulose-composite fibre reinforced 3D polypyrrole electrodes for energy storage applications2014Inngår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 6, nr 21, s. 13068-13075Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is demonstrated that 3D nanostructured polypyrrole (3D PPy) nanocomposites can be reinforced with PPy covered nanocellulose (PPy@nanocellulose) fibres to yield freestanding, mechanically strong and porosity optimised electrodes with large surface areas. Such PPy@nanocellulose reinforced 3D PPy materials can be employed as free-standing paper-like electrodes in symmetric energy storage devices exhibiting cell capacitances of 46 F g(-1), corresponding to specific electrode capacitances of up to ∼185 F g(-1) based on the weight of the electrode, and 5.5 F cm(-2) at a current density of 2 mA cm(-2). After 3000 charge/discharge cycles at 30 mA cm(-2), the reinforced 3D PPy electrode material also showed a cell capacitance corresponding to 92% of that initially obtained. The present findings open up new possibilities for the fabrication of high performance, low-cost and environmentally friendly energy-storage devices based on nanostructured paper-like materials.

  • 452.
    Wang, Zhaohui
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Xu, Chao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Tammela, Petter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Huo, Jinxing
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Nyholm, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Flexible freestanding Cladophora nanocellulose paper based Si anodes for lithium-ion batteries2015Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, nr 27, s. 14109-14115Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Freestanding, lightweight and flexible Si paper anodes are prepared via a straightforward paper-making process using Cladophora nano-cellulose, silicon nanoparticles and carbon nanotubes as the building blocks. The uniform Si particle distribution and strong adhesion of the Si nanoparticles to the porous, conductive and flexible nanocellulose/carbon nanotube 3D matrix yield specific capacities of up to 800 mA h g(-1) (based on the weight of whole electrode) and very good cycling performances.

  • 453.
    Westerling, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Interaction of Cylindrical Penetrators with Ceramic and Electromagnetic Armour2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Armoured vehicles have traditionally used steel armour as protection against penetrators such as projectiles and shaped charge jets. The latter produce a thin stretching metal jet, usually of copper, with a tip velocity of about 7-8 km/s. In order to obtain more weight-efficient solutions, there is a search for lighter materials and other protection techniques. In this thesis, ceramic and electromagnetic armours are studied. Ceramic materials are lighter than steel, and their high compressive strength makes them useful as armour materials. Electromagnetic armour consists of two metal plates connected to an electric power supply capable of delivering a strong current pulse. A conductive penetrator passing through both plates is destroyed by the effects of the resulting current.

    Tests of the ceramic armour materials alumina and boron carbide were performed with reverse impact technique, which signifies that a target assembly (ceramic confined in a metal cylinder) was launched by a gun towards a projectile placed in front of the gun barrel. By this technique yaw was eliminated, but the geometric scale had to be very small. Therefore, we studied scaling laws for ceramic armour through a series of tests with direct impact technique and projectile diameters from 2 to 10 mm. The small scale has the advantage that flash X-ray photography can be used to photograph the projectile inside the ceramic target. The phenomenon of interface defeat or dwell was also demonstrated. It signifies that the ceramic, at least for a short time, can withstand the impact pressure so that the projectile just flows out onto the target surface. A transition velocity, above which dwell does not occur, was determined. Simulations were performed with the continuum-dynamic code Autodyn and by use of a model for the brittle ceramic materials by Johnson and Holmquist. The simulations reasonably well represented the penetration behaviour above the transition velocity. They also did below, if under this condition the ceramic model was forced to remain undamaged.

    The performance of electromagnetic armour was tested against a shaped charge jet. The jet was registered with shadowgraph flash X-ray photography between the plates and after passing through the plates. The current through the jet and the voltage over the plates were also registered. The current caused heating leading to melting and even vaporization. The magnetic Lorentz force compressed the jet radially, and as this effect increases with decreasing jet radius, instability may arise. Explosions in the compressed regions resulted in a fragmented jet with disk-shaped fragments which are less effective penetrators than the elongated fragments obtained in the absence of current. We also performed a theoretical study, in which the penetrator was subjected to small elastic strains only and the current was constant. The magnetic field was determined by FFT, and the stresses due to the Lorentz force were calculated with a semi-analytical method. The velocity skin effect was demonstrated.

    Delarbeid
    1. Influence of scale on the penetration of tungsten rods into steel-backed alumina targets
    Åpne denne publikasjonen i ny fane eller vindu >>Influence of scale on the penetration of tungsten rods into steel-backed alumina targets
    1996 (engelsk)Inngår i: International Journal of Impact Engineering, ISSN 0734-743X, E-ISSN 1879-3509, Vol. 18, nr 4, s. 403-416Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    As ballistic tests are often performed in reduced geometrical scale, the scaling laws are important for the interpretation of the results. In this study, we tested the validity of replica scaling, by which we mean that all geometrical dimensions are scaled uniformly, while the materials and the impact velocity are kept the same. Long tungsten projectiles with length-to-diameter ratio 15 were fired against unconfined alumina targets with steel backing. The tests were carried out with impact velocities 1500 m s−1 and 2500 m s−1, and in three different scales with projectile lengths 30, 75 and 150 mm (diameters 2, 5 and 10 mm). The alumina targets were photographed by means of a high-speed camera, and the tungsten projectiles were photographed inside the alumina targets by means of flash radiography. Also, the residual penetrations in the steel backings were measured. The Johnson-Holmquist model for ceramic materials was implemented into the AUTODYN code, which was used for simulation of the experiments. The agreement between results of experiment and simulation was fair, and over the tested interval of scales replica scaling was found to be valid with reasonable accuracy.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-92318 (URN)10.1016/0734-743X(95)00049-G (DOI)
    Tilgjengelig fra: 2004-11-03 Laget: 2004-11-03 Sist oppdatert: 2017-12-14bibliografisk kontrollert
    2. High velocity penetration of homogeneous, segmented and telescopic projectiles into alumina targets
    Åpne denne publikasjonen i ny fane eller vindu >>High velocity penetration of homogeneous, segmented and telescopic projectiles into alumina targets
    1997 (engelsk)Inngår i: Int. J. Impact Engng, Vol. 20, s. 817-827Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-41209 (URN)
    Tilgjengelig fra: 2005-04-28 Laget: 2005-04-28 Sist oppdatert: 2013-08-30
    3. Tungsten long-rod penetration into confined cylinders of boron carbide at and above ordnance velocities
    Åpne denne publikasjonen i ny fane eller vindu >>Tungsten long-rod penetration into confined cylinders of boron carbide at and above ordnance velocities
    2001 (engelsk)Inngår i: International Journal of Impact Engineering, ISSN 0734-743X, E-ISSN 1879-3509, Vol. 25, nr 7, s. 703-714Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The purpose was to investigate the influence of impact velocity and confinement on the resistance of boron carbide targets to the penetration of tungsten long-rod projectiles. Experimental tests with impact velocities from 1400 to 2600 m/s were performed using a two-stage light-gas gun and a reverse impact technique. The targets consisted of boron carbide cylinders confined by steel tubes of various thicknesses. Simulations were carried out using the AUTODYN-2D code and Johnson–Holmquist's constitutive model with and without damage evolution. The experimental results show that the penetration process had different character in three different regions. At low-impact velocities, no significant penetration occurred. At high-impact velocities, the relation between penetration velocity and impact velocity was approximately linear, and the penetration was steady and symmetrical. In between, there was a narrow transition region of impact velocities with intermittent and strongly variable penetration velocity. In the lower part of this region, extended lateral flow of the projectile took place on the surface of the target. The influence of confinement on penetration velocity was found to be small, especially at high-impact velocities. The simulated results for penetration velocity versus impact velocity agreed fairly well with the experimental results provided damage evolution was suspended below the transition region.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-92320 (URN)10.1016/S0734-743X(00)00072-5 (DOI)
    Tilgjengelig fra: 2004-11-03 Laget: 2004-11-03 Sist oppdatert: 2017-12-14bibliografisk kontrollert
    4. Experimental Study of Electromagnetic Effects on Solid Copper Jets
    Åpne denne publikasjonen i ny fane eller vindu >>Experimental Study of Electromagnetic Effects on Solid Copper Jets
    Vise andre…
    2010 (engelsk)Inngår i: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 77, nr 1, s. 011010-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this paper we present a study of the interaction between all electric current pulse and a solid copper jet. Experiments were performed using a dedicated pulsed power supply delivering a current pulse of such amplitude, rise little, and duration that the jet is efficiently affected. The copper jet was created by using a shaped charge warhead. All electrode configuration consisting of two aluminum plates with a separation distance of 150 mm was used. The discharge current pulse and the voltages at the capacitors and at the electrodes were measured to obtain data oil energy deposition in and the resistance of the jet and electrode contact region. X-ray diagnostics were used to radiograph the jet, and by analyzing the radiograph, the degree of disruption of the electrified jet could be obtained. It was found that a current pulse with an amplitude of 200-250 kA and a rise time of 16 mu s could strongly enhance the natural fragmentation of the jet. In this case, the initial electric energy was 100 kJ and about 90% of the electric energy was deposited in the jet and electrodes. At the exit of the electrode region, the jet fragments formed rings with a radial velocity of up to 200 m/s, depending oil the initial electric energy in the pulsed power supply. [DOI: 10.1115/1.3172251]

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-127434 (URN)10.1115/1.3172251 (DOI)000271574200010 ()
    Tilgjengelig fra: 2010-07-14 Laget: 2010-07-13 Sist oppdatert: 2018-05-30bibliografisk kontrollert
    5. Interaction between solid copper jets and powerful electric current pulses
    Åpne denne publikasjonen i ny fane eller vindu >>Interaction between solid copper jets and powerful electric current pulses
    Vise andre…
    2011 (engelsk)Inngår i: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 78, nr 2, s. 021006-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The interaction between a solid copper jet and an electric current pulse is studied. Copper jets that were created by a shaped charge device were passed through an electrode configuration consisting of two aluminum plates with a separation distance of 150 mm. The electrodes were connected to a pulsed power supply delivering a current pulse with amplitudes up to 250 kA. The current and voltages were measured, providing data on energy deposition in the jet and electrode contact region, and flash X-ray diagnostics were used to depict the jet during and after electrification. The shape of, and the velocity distributions along, the jet has been used to estimate the correlation between the jet mass flow through the electrodes and the electrical energy deposition. On average, 2.8 kJ/g was deposited in the jet and electrode region which is sufficient to bring the jet up to the boiling point. A model based on the assumption of a homogenous current flow through the jet between the electrodes underestimates the energy deposition and the jet resistance by a factor five compared to the experiments, indicating a more complex current flow through the jet. The experimental results indicate the following mechanism for the enhancement of jet break-up. When electrified, the natural-formed necks in the jet are subjected to a higher current density compared to other parts of the jet. The higher current density results in a stronger heating and a stronger magnetic pinch force. Eventually, the jet material in the neck is evaporated and explodes electrically, resulting in a radial ejection of vaporized jet material.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-197561 (URN)10.1115/1.4002568 (DOI)
    Tilgjengelig fra: 2013-03-27 Laget: 2013-03-27 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    6. Stresses in a long cylindrical conductor moving axially through a pair of electrode plates under stationary conditions
    Åpne denne publikasjonen i ny fane eller vindu >>Stresses in a long cylindrical conductor moving axially through a pair of electrode plates under stationary conditions
    2013 (engelsk)Inngår i: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 80, nr 2, s. 021013-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In a conductor carrying electric current, the Lorentz force gives rise to mechanical stresses. Here, we study a long elastic cylindrical conductor that moves axially with constant velocity through two electrode plates. The aims are to explore how the stresses in the conductor depend on the velocity in the stationary case of constant current and to assess the validity of the analytic method used. The diffusion equation for the magnetic flux density is solved by use of Fourier transform, and the current density is determined. The stresses, due to the Lorentz force, are found by use of an analytic method combining the solutions of a quasi-static radial problem of plane deformation and a dynamic axial problem of uniaxial stress. They are also determined through FE analysis. Radial field profiles between the plates indicate a velocity skin effect signifying that the current and the magnetic field are concentrated near the cylindrical surface up-stream and are more uniformly distributed downstream. The radial and hoop stresses are compressive, while the axial stress is tensile. The von Mises effective stress increases towards the symmetry axis, in the downstream direction, and with velocity. There are circumstances under which a large current can produce an effective stress in a copper conductor of the order of the yield stress without causing a significant temperature rise. The stresses obtained with the two methods agree well, even relatively near the electrode plates. The analytical method should be useful in similar cases as well as for the provision of test cases for more general simulation tools.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot tillämpad mekanik
    Identifikatorer
    urn:nbn:se:uu:diva-187308 (URN)10.1115/1.4007221 (DOI)000326175400026 ()
    Tilgjengelig fra: 2012-12-04 Laget: 2012-12-04 Sist oppdatert: 2017-12-07bibliografisk kontrollert
  • 454.
    Westerling, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Lundberg, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Stresses in a long cylindrical conductor moving axially through a pair of electrode plates under stationary conditions2013Inngår i: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 80, nr 2, s. 021013-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In a conductor carrying electric current, the Lorentz force gives rise to mechanical stresses. Here, we study a long elastic cylindrical conductor that moves axially with constant velocity through two electrode plates. The aims are to explore how the stresses in the conductor depend on the velocity in the stationary case of constant current and to assess the validity of the analytic method used. The diffusion equation for the magnetic flux density is solved by use of Fourier transform, and the current density is determined. The stresses, due to the Lorentz force, are found by use of an analytic method combining the solutions of a quasi-static radial problem of plane deformation and a dynamic axial problem of uniaxial stress. They are also determined through FE analysis. Radial field profiles between the plates indicate a velocity skin effect signifying that the current and the magnetic field are concentrated near the cylindrical surface up-stream and are more uniformly distributed downstream. The radial and hoop stresses are compressive, while the axial stress is tensile. The von Mises effective stress increases towards the symmetry axis, in the downstream direction, and with velocity. There are circumstances under which a large current can produce an effective stress in a copper conductor of the order of the yield stress without causing a significant temperature rise. The stresses obtained with the two methods agree well, even relatively near the electrode plates. The analytical method should be useful in similar cases as well as for the provision of test cases for more general simulation tools.

  • 455. Wickholm, K.
    et al.
    Lorentzon, A.
    Berthold, F.
    Vomhoff, H.
    Gamstedt, Kristofer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Varna, J.
    Waljansson, A.
    Junel, K.
    Wood-derived renewable materials2011Inngår i: Partner Update - Inventia Customer Magazine for Partners, Vol. 4, s. 6-7Artikkel i tidsskrift (Fagfellevurdert)
  • 456.
    Wigh, Malin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    ANVÄNDNING AV PRODUTIVITETSVERKTYG FÖR ATT NÅ UPPSATTA PROJEKTMÅL: En undersökning på ett Skanska projekt2013Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    This is a result of a diploma work in construction engineering. The purpose of this thesis is to investigate the nature of the productivity in a given project and how the Skanska productivity tools were used in this project.

    Interviews were held among workers and management to get some answers on what affected the work and its productivity. The result of the thesis showed that the productivity tools as propulsion analysis and “goal cards”, were not used to a wide extent in this project. Furthermore there was almost no feedback for the one who made the calculation and the offer for the project, which might affect the results on projects negatively in the future.

    Within the project there was a lot of waiting time which affected the productivity. To avoid this there is a need for better planning among cooperating companies and a better planning in the beginning of the project.

  • 457.
    Wikesjö, Oscar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    Enlund, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    3D-MODELLBYGGHANDLING:VERKLIGHET ELLER UTOPI?: En studie inriktad på kvalitetssäkring2018Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    The building industry is facing large changes regardingtechnology: paper drawings are transforming into 3D models andmore information is becoming digital. This report diagnosesweaknesses that exist in today’s quality controls of 3D models andcreates the foundation for quality control of 3D models.An ambiguous review process for 3D models exists due to a lack ofclear guidelines for quality control. This report examines thecurrent methods used for reviewing 3D models and defines the areaswhich need improvement.The study is made at White Arkitekter in conjunction with anongoing project, Celsius, which is modeled in 3D. The model ismade in Revit and the construction documents are delivered as partof the 3D model.The information for this study is based on relevant literature andinterviews with four respondents. Each respondent has a differentrole within and experience from the Celsius project. Qualitativeinterviews were performed.The result of the study shows that the respondents performedquality control within the area they were responsible for. Inaddition, the study shows that the existing quality controlmethods were not compatible for 3D modeling.Furthermore, it shows that proper filters for model objects makesthe quality control of 3D models easier. All respondents agreedthat they could achieve their main aim.This study has resulted in guidelines for creating a qualitycontrol routine when working with 3D modeling.Finally, there are recommendations for potential tools regardingquality control of 3D models for future research.

  • 458.
    Wiklund, U
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Gunnars, J
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Hogmark, S
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence of residual stresses on fracture and delamination of thin hard coatings1999Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 232, nr 2, s. 262-269Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    The risk of fracture and delamination of residually stressed coating systems is examined. Stress concentrations are generated at the interface of coated systems where the substrate deviates from bring perfectly smooth, flat and infinitely large. Using fin

  • 459. Wu, Dan
    et al.
    Afshar, Reza
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik. Uppsala University.
    Gamstedt, Kristofer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Calculation of Joint Stiffness Parameters of the Section Replica of the Vasa Ship2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Stiffness of joints in wooden structures in cultural heritage is not easily measured in situ, since the application of load may put the object at risk. Instead, replicas of joints can be built and tested mechanically to quantify joint stiffness. The stiffness values are valuable in finite element models of the structures in design of improved structural support systems. In order to establish a simplified but accurate enough model of the 17th century Vasa ship for better preservation, it is essential to determinate the stiffness behavior of the connecting joint between hull and deck beam, which is believed to be semi-rigid due to the degradation of the composing oak-wood and the deformation of wood around the steel bolts. A method based on force and moment equilibrium is proposed to determinate the joint stiffness parameters, and the mechanical behavior of the joint is substituted by some spring elements in the finite element (FE) model of the entire ship. From the FE model of the section of the ship, which was compared and validated with the experimental tests of the full-scale section replica of the Vasa ship, the coefficients of the spring elements are calculated by the undertaken moment and the relative rotation angle between the deck beam and the hull of the ship. The calculated spring stiffnesses generally show similar trend as the replica experiments. The small relative displacement indicates a high stiffness of the joint. Due to the complexity of the joint structure, the value for spring stiffness becomes sensitive to the approximations made during the calculation of the moment and the position of selected nodes to calculate the rotation angle. However, the sensitivity of spring coefficients needs to be tested in term of global deformation of the entire ship. In general, the proposed method describes a scheme that shows how joint stiffness parameters can be estimated for valuable and sensitive structures by way of a joint experimental-numerical approach in a replica of the original components.

  • 460.
    Wu, Dan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Ferguson, Stephen
    ETH Zurich, Switzerland.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Young’s modulus of trabecular bone at the tissue level: A review2018Inngår i: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 78, s. 1-12Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The tissue-level Young’s modulus of trabecular bone is important for detailed mechanical analysis of bone and bone-implant mechanical interactions. However, the heterogeneity and small size of the trabecular struts complicate an accurate determination. Methods such as micro-mechanical testing of single trabeculae, ultrasonic testing, and nanoindentation have been used to estimate the trabecular Young’s modulus. This review summarizes and classifies the trabecular Young’s moduli reported in the literature. Information on species, anatomic site, and test condition of the samples has also been gathered. Advantages and disadvantages of the different methods together with recent developments are discussed, followed by some suggestions for potential improvement, for future work. In summary, this review provides a thorough introduction to the approaches used for determining trabecular Young’s modulus, highlights important considerations when applying these methods and summarizes the reported Young’s modulus for follow-up studies on trabecular properties.

    Fulltekst tilgjengelig fra 2020-08-05 12:40
  • 461.
    Wu, Dan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Quantification of strains and cracks in trabecular bone by digital volume correlation: A case studyManuskript (preprint) (Annet vitenskapelig)
  • 462.
    Wu, Dan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Joffre, Thomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Gallinetti, Sara
    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.
    Ferguson, Stephen J.
    Institute for Biomechanics, ETH Zürich, Switzerland.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Elastic Modulus Of Human Single Trabeculae Estimated by Synchrotron CT Experiments And Numerical Models2017Konferansepaper (Fagfellevurdert)
  • 463.
    Wu, Dan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap. Uppsala University.
    Pujari-Palmer, Michael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Bojan, Alicja
    Department of Orthopaedics, Sahlgrenska University Hospital Gothenburg.
    Palmquist, Anders
    Department of Biomaterials, University of Gothenburg.
    Procter, Philip
    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.
    Stephen, Ferguson
    ETH Zurich, Switzerland.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    The effect of augmentation materials on screw pullout resistance from human trabecular boneManuskript (preprint) (Annet vitenskapelig)
  • 464.
    Wu, Dan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    van Dijk, Nico P
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Joffre, Thomas
    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.
    Stephen, Ferguson
    ETH Zurich, Switzerland.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    A combined experimental and numerical method to estimate the elastic modulus of single trabeculae2017Manuskript (preprint) (Annet vitenskapelig)
  • 465.
    Wu, Zhigang
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Luoyu Rd 1037, Wuhan 430074, Hubei, Peoples R China.
    Zhang, Shuo
    Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Luoyu Rd 1037, Wuhan 430074, Hubei, Peoples R China.
    Vorobyev, Alexey
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Gamstedt, E. Kristofer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Wu, Kang
    Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Luoyu Rd 1037, Wuhan 430074, Hubei, Peoples R China.
    Guo, Chuanfei
    Southern Univ Sci & Technol, Dept Mat Sci & Engn, Shenzhen 518055, Peoples R China.
    Jeong, Seung Hee
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Seamless modulus gradient structures for highly resilient, stretchable system integration2018Inngår i: MATERIALS TODAY PHYSICS, ISSN 2542-5293, Vol. 4, s. 28-35Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hybrid system integration of rigid components into stretchable systems is often necessary when targeting for valuable functions in various scenarios. Among them, (Young's) modulus gradient structures for system integration demonstrate excellent mechanical performance when stretched. However, the mechanical reliability is still limited under large deformation due to the inherent interface between materials of different modulus. Here, a seamless transition between heterogeneous moduli parts made with polydimethylsiloxane (PDMS)-based elastomers is presented for stretchable system integration by simply tuning their modulus via introducing a small amount of an additive into some parts of the substrate. These gradient structures not only provide a high stretchability (similar to 250%) for the overall system, but also improve the resilience of the system (can be stretched up to 50,000 cycles from 0 to 150% global strain) at the same time. The seamless modulus gradient structures provide a simple and effective way of allowing highly resilient and stretchable system integration for various soft intelligent systems.

  • 466.
    Wänglund, Adam
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    Eriksson, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    UTVECKLING AV PROJEKTERINGSANVISNINGAR: En utredning rörande hur projekteringsanvisningar bör utformas2017Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    In the process of erecting a building, the precursory design and planning stage is of paramount importance. The foremost managing tool during this stage constitutes of the design guidelines, established by the developer. This report contains a study of how to model said guidelines to achieve a more effective way of working, without compromising the final product, produced at the request of Swedish housing developer Småa AB. The study is based on a series of interviews, where persons involved in the design and planning stage have been asked to share their experiences and opinions about the process and how it affects the end result. The study is based on a series of interviews, where persons involved in the planning and design stage have been asked to share their experiences and opinions regarding the development process and how it affects the end result. During the processing of the collected material, three distinct subject areas emerged; the importance of clear design guidelines, what the design guidelines should cover and how to ensure the quality of the product. Based on these subject areas, the authors have devised a set of recommendations to ensure an effective working method and the quality of the end result.

  • 467.
    Yang, Ting
    et al.
    Division of Coating Technology and Division of Biocomposites, Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH, Stockholm.
    Long, Hui
    Division of Coating Technology and Division of Biocomposites, Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH, Stockholm.
    Malkoch, Michael
    Division of Coating Technology and Division of Biocomposites, Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH, Stockholm.
    Gamstedt, E. Kristofer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Berglund, Lars
    Division of Coating Technology and Division of Biocomposites, Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH, Stockholm.
    Hult, Anders
    Division of Coating Technology and Division of Biocomposites, Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH, Stockholm.
    Characterization of Well-Defined Poly(ethylene glycol) Hydrogels Prepared by Thiol-ene Chemistry2011Inngår i: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 49, nr 18, s. 4044-4054Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Considering the large number of applications for hydrogels, a better understanding of the relation between molecular structure and mechanical properties for well-defined hydrogel is essential. A new library has been compiled of poly(ethylene glycol) polymers (PEG) of different length end functionalized with diallyl, dithiol, and dimethacrylate, and crosslinked with complementary trifunctional crosslinkers. In this study, the hydrogels were initially analyzed by FT-Raman and NMR to study the conversion ratio of the functional groups. The effects of solvent type, solid content concentration, curing time and length of the PEG chains on the final leaching, swelling and tensile properties of the hydrogels were studied.

  • 468.
    Zafra-Camón, Guillermo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Calculation of global properties of a multi-layered solid wood structure using Finite Element Analysis2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Finite Element Method (FEM) is a powerful numerical tool which, combined with the fast development of Computer Science in the lastdecades, had made possible to perform mechanical analysis of a widerange of bodies and boundary conditions.

    However, the complexity of some cases may turn the calculationprocess too slow and sometimes even unaffordable for most computers. This work aims to simplify an intricate system of layers withdifferent geometries and material properties by approximating itthrough a homogeneous material, with unique mechanical parameters.Besides the Finite Element analysis, a theoretical model is created, in order to understand the basis of the problem, and, as a firstapproach, check whether the assumptions made in the FEM model areacceptable or not.

    This work intends to make a small contribution to the understandingof the mechanical behaviour of the Vasa vessel, which will eventuallylead to the design of a new support structure for the ship. The preservation of the Vasa is a priority for the Swedish Property Board, as it is one of the main monuments of Sweden.

  • 469.
    Zetterström, Björn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    Jämförelsestudie för tre olika metoder att beräkna genomstansning i betong: Skillnader i genomstansningskapacitet för metoderna i BBK04, EK2 och BHB2014Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Before the European construction standards were introduced in January 2011, it was mainly the

    method in BBK04 that was used for calculating punching capacity in concrete structures, and in less

    common cases the method in BHB. The method of BBK04 is easy to use and have had the same

    structure since the first was published in 1979. The Concrete handbook method (BHB) where usually

    only used when a higher punching capacity was needed and the cross-sectional height where fixed,

    calculations using this method entails more work, but will in return usually give a higher capacity. It

    also allows the use of shear reinforcement to increase the cross-section capacity. The method of

    calculating punching shear in EC2 differs largely from the methods of BBK04 and BHB. The method

    is similar to a large extent of the so called “alternative model” to calculate the shear capacity in

    BBK04.

    The purpose of this study is to make a comparison between the different methods, mentioned above.

    The study aims to find out which one of these models/methods that will provide the maximum

    punching capacity and utilization. The results of the study can then be used to make a quick and fairly

    assessment if a construction can withstand the same load situation that it was originally analyzed for

    when using the European construction standards.

    In the comparison, three different kinds of concrete qualities was used C25/35-C45/55, and four

    different kinds of reinforcement contents ρ = 0.02 – 0.1%, and a span of effective cross section heights

    in the range d = 0.1 - 2m.

    The study shows that for an older concrete structure dimensioned in accordance with BKR and

    BBK04 it’s very likely that the utilization when recalculating it with the Eurocode will not be a

    problem. This seems to apply to all concrete qualities, reinforcing contents and cross-sectional heights

    used in this study. The method in EC2 provides between 20-130 % higher punching capacities. The

    difference between the two methods increases with the cross-sectional height. For effective heights

    over 0.2 m the punching capacity is at least 36 % greater than what is obtained with method in

    BBK04. The load in EC2 is in this case 16-27 % greater than the load obtained when using BKR.

    Even a quite significant increase of the loads could in most cases be done.

    When then concrete manual method (BHB) is used and the reinforcement content of the structure is

    above 0.5 % that method generally achieves better capacities or at least equal capacities compared to

    the method in EC2. For low cross-sectional heights, the method in EC2 sometimes gives better values

    of capacity. It is unlikely that a structure that has been optimized with the help of BHB could

    withstand the greater loads that are achieved when using the Euro codes. This also applies to crosssections that needs shear reinforcement.

  • 470.
    Zoma, Fati
    et al.
    Univ Ouaga 01 Pr Joseph KI ZERBO, Lab Phys & Chem Environm, 03 BP 7021, Ouagadougou, Burkina Faso.
    Toguyeni, David Y. K.
    Univ Ouaga 01 Pr Joseph KI ZERBO, Lab Phys & Chem Environm, 03 BP 7021, Ouagadougou, Burkina Faso.
    Coulibaly, Ousmane
    Univ Ouaga 01 Pr Joseph KI ZERBO, Lab Phys & Chem Environm, 03 BP 7021, Ouagadougou, Burkina Faso.
    Hassel, Ivón
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    Ouedraogo, Abdoulaye
    Univ Ouaga 01 Pr Joseph KI ZERBO, Lab Thermal & Renewable Energies, 03 BP 7021, Ouagadougou, Burkina Faso.
    Potentials of an Eco-Friendly Composite in Hot-Dry Climate2018Inngår i: Journal of Renewable Materials, ISSN 2164-6325, E-ISSN 2164-6341, Vol. 6, nr 1, s. 47-54Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study aims to show the aptitude of a locally made composite for providing thermal comfort and mechanical resistance in buildings in hot-dry climates. The thermal characterization reveals that the thermal diffusivity of the studied material is lower than that of commonly used materials such as agglomerated and full cinderblocks and laterite blocks and therefore is a better insulating material. In addition, its thermal inertia is the highest compared to commonly used materials of agglomerated and full cinderblocks, laterite blocks and compressed earth blocks, which implies a longer time lag. On the basis of mechanical resistance, with a compression resistance of 3.61 MPa, the studied material meets the requirement of CRATerre and NBF 02-003 (2009) as a material for construction of single-storey buildings. Therefore, this material, containing 1% Hibiscus sabdariffa fibers and compacted by vibration, is a suitable material for the walls of standing buildings and for thermal comfort in hot dry climates.

  • 471.
    Åberg, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Lägre värmebehov leder till effektivare fjärrvärme2013Inngår i: Energi magasinet, Vol. 35, nr 3, s. 8-10Artikkel i tidsskrift (Fagfellevurdert)
  • 472.
    Åberg, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Swedish District Heating Sensitivity: Future Heat Demand Change and Electricity Market Dynamics2013Inngår i: Euro Heat & Power, ISSN 1613-0200-22698, Vol. 10, nr 3, s. 21-25Artikkel i tidsskrift (Fagfellevurdert)
  • 473.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Henning, Dag
    Optimisation of a Swedish district heating system with reduced heat demand due to energy efficiency measures inr esidential buildings2011Inngår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 39, nr 12, s. 7839-7852Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development towards more energy efficient buildings, as well as the expansion of district heating (DH) networks, is generally considered to reduce environmental impact. But the combined effect of these two progressions is more controversial. A reduced heat demand (HD) due to higher energy efficiency in buildings might hamper co-production of electricity and DH. InSweden,co-produced electricity is normally considered to displace electricity from less efficient European condensing power plants. In this study, a potential HD reduction due to energy efficiency measures in the existing building stock in the Swedish city Linkoping is calculated. The impact of HD reduction on heat and electricity production in the Linkoping DH system is investigated by using the energy system optimisation model MODEST. Energy efficiency measures in buildings reduce seasonal HD variations. Model results show that HD reductions primarily decrease heat-only production.The electricity-to-heat output ratio for the system is increased for HD reductions up to 30%. Local and global CO2 emissions are reduced. If co-produced electricity replaces electricity from coal-fired condensing power plants, a 20% HD reduction is optimal for decreasing global CO2 emissions in the analysed DH system.

  • 474.
    Åslund, Anton
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    5D-modellering i byggskedet: Med inriktning på anläggningsbranschen2014Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    With those utilities and possibilities we have today, 3D-models should be usted more

    than they are. The posibilities to work further with these models are enormous.

    The purpose with this report is to investigate why the BIM technology isn’t used to

    its fully potential in the construction industry. And also to investige the posibilities to

    implement the technique further by interconnecting the 3D-model to more

    information consisting of 4D-BIM and 5D-BIM. By a comparison between the real

    estate industry and the construction industry produce solutions that can be implied in

    the construction industry.

    The methods that have been used in this operation is a study of literature and

    interviews of experts in the industry. Based on these methods the author has

    concluded several reasons why 5D-modeling is so limited as it is. This area is rather

    undiscovered, few in the industry even thinks of this as a problem, or an area that

    needs improvement, so the investigation in the area is very limited. Besides, the time

    it takes for a person to learn a new working progress is time the person often doesn’t

    have. Plus that the new is frightening, the time it takes to learn the new way is

    unknown and the time it takes to imply it in the projekt is unknown. The way you’ve

    always worked is safe and you know approximitly how long it’s going to take.

    One thing that is notable in the construction industry is that the demands from the

    clients is starting to appear and the competens of the contractors doesn’t exist. And

    there is a fatal chans that the demands will increase much faster than the development

    of competens in the industry. For the industry to keep develop in the right pace, the

    industry must dare to invest in 5D-modeling. By giving priority to learn a more

    efficient way of working, by daring to invest economically in software and education of

    competens and to look at these costs as an investment in the future and not a cost

    for the ongoing projekts.

  • 475. Åslund, P.
    et al.
    Hägglund, R.Carlsson, L.Isaksson, PerUppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Modeling of global and local buckling of corrugatedboard panels loaded in edgewise compression2012Konferanseproceedings (Fagfellevurdert)
  • 476. Åslund, Pär E.
    et al.
    Hägglund, Rickard
    Carlsson, Leif A.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    An analysis of strain localization and formation of face wrinkles in edge-wise loaded corrugated sandwich panels using a continuum damage model2015Inngår i: International Journal of Solids and Structures, ISSN 0020-7683, E-ISSN 1879-2146, Vol. 56-57, s. 248-257Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper examines the compressive failure mechanism in edge-to-edge loaded corrugated sandwich panels. The formation of face wrinkles is specifically considered. A detailed finite element model of face sheets and web core of a sandwich panel was developed to provide insight on the failure mechanism. A gradient enhanced continuum damage theory was implemented to capture length effects caused by the material microstructure including formation of damage in the face sheets and core. Distributions of strains in the face sheets determined from finite element analysis (FEA) are compared to experimentally measured strains. The predicted location and orientation of the face wrinkle, as indicated by high values of the second principal strain, agrees well with experimental observations. Load vs. out-of-plane deflection curves obtained from FEA with the gradient enhanced damage material model are compared to those obtained from a linear-elastic material model and experimentally determined curves. The gradient enhanced solution gives qualitatively better agreement with experimental results, although the magnitudes of strains are less than those determined experimentally. 

  • 477.
    Åström, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    Användandet av mobila enheter med appsystem och appars fackmannamässiga potential inom byggbranshen2014Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Mobile devices such as tablets and smartphones are quite common in this day. The author of this thesis wanted to know how common these mobile devices are in the building industry and how they are used and what potential an app could have. The author thus conducted an investigation on this matter, mainly in the form of interviews.

    Answers given by the interviews were then used as a basis to survey the usage of mobile devices and the usage of different kinds of apps. An investigation of different apps with the potential to be used by professionals in the building industry has been carried through. Apps which manage such things as scanning documents, measuring distances and handle communication. A further more advanced study of a floor plan making app, called MagicPlan has also been done. The equipment that were used were Samsung Galaxy S2, Apple iPad , Samsung Note 10.1 Tablet, Leica Disto, Leica Scanstation C10, Canon Pixma MP270.

    The results of the examination show that the usages of mobile devices are widely spread in the building industry, however, seldom to its full potential. The results also indicates that the tested apps likely can be used by professionals in some cases.

78910 451 - 477 of 477
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