| 1. |
- Li, Wei, et al.
(författare)
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Generalized stacking fault energy of gamma-Fe
- 2016
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Ingår i: Philosophical Magazine. - : Taylor & Francis. - 1478-6435 .- 1478-6443. ; 96:6, s. 524-541
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the generalized stacking fault energy ( [GRAPHICS] -surface) of paramagnetic [GRAPHICS] -Fe as a function of temperature. At static condition, the face-centred cubic (fcc) lattice is thermodynamically unstable with respect to the hexagonal close-packed lattice, resulting in a negative intrinsic stacking fault energy (ISF). However, the unstable stacking fault energy (USF), representing the energy barrier along the [GRAPHICS] -surface connecting the ideal fcc and the intrinsic stacking fault positions, is large and positive. The ISF is calculated to have a strong positive temperature coefficient, while the USF decreases monotonously with temperature. According to the recent plasticity theory, the overall effect of temperature is to move paramagnetic fcc Fe from the stacking fault formation regime ( [GRAPHICS] K) towards maximum twinning ( [GRAPHICS] K) and finally to a dominating full-slip regime ( [GRAPHICS] K). Our predictions are discussed in connection with the available experimental observations.
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| 2. |
- Fachrizal, Reza, 1993-, et al.
(författare)
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Residential building with rooftop solar PV system, battery storage and electric vehicle charging : Environmental impact and energy matching assessments for a multi-family house in a Swedish city
- 2022
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Ingår i: 21st Wind & Solar Integration Workshop (WIW 2022). - : The Institution of Engineering and Technology (IET). - 9781839538339 ; , s. 565-572
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Konferensbidrag (refereegranskat)abstract
- In this paper, environmental impact and energy matching assessments for a residential building with a rooftop photovoltaic (PV)system, battery energy storage system (BESS) and electric vehicles (EV) charging load are conducted. This paper studies a real multi-family house with a rooftop PV system in a city located on the west-coast of Sweden, as a case study. The environmental impact parameter assessed in this study is CO2 equivalent (CO2-eq) emissions. It should be noted that the CO2-eqemission assessment takes into account the whole life cycle, not only the operational processes. The assessments consider boththe household and transport energy demands for the building’s residents. Results show that, CO2-eq emissions from the building electricity usage are increased by 1.65 ton/year with the integrationof PV-BESS system. This is because the Swedish electricity mix has a lower CO2-eq emissions than the PV-BESS system. The total CO2-eq emissions from the transport needs of the building’s residents are significantly decreased, by 32.9 ton/year, if they switch from fossil-fuel-powered cars to EVs. However, the integration of EVs increases the power demand significantly which could be problematic for the power system. In such scenario, the highly-utilized distributed PV systems, enhanced by BESS, can be a low-carbon solution to address the increased power demand challenges coming from transport electrification.
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| 3. |
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| 4. |
- Mossberg, Magnus, et al.
(författare)
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Parametric identification of viscoelastic materials from time and frequency domain data
- 2001
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Ingår i: Inverse Problems in Engineering. - : Informa UK Limited. - 1068-2767 .- 1029-0281. ; 9:6, s. 645-670
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Tidskriftsartikel (refereegranskat)abstract
- In this paper a parametric model of the elasticity modulus of a viscoelastic material (polypropylene) is determined by measured strains from wave propagation experiments. The identification of the model parameters is carried out both in the time and in the frequency domain. The advantages and limitations of either approach is discussed. Our main result is that a good representation of the elasticity modulus can be obtained by a general standard linear solid with three elements or seven free parameters. The model is valid over the same frequency range as that of the data, which in the present case extends from 100 Hz to 10 kHz. Such a model makes it possible to perform direct time simulations by time-stepping algorithms.
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| 5. |
- Rensfelt, Agnes, et al.
(författare)
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Optimal sensor locations for nonparametric identification of viscoelastic materials
- 2008
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Ingår i: Automatica. - : Elsevier BV. - 0005-1098 .- 1873-2836. ; 44:1, s. 28-38
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Tidskriftsartikel (refereegranskat)abstract
- The problem of optimal sensor locations in nonparametric identification of viscoelastic materials is considered. Sensor locations have previously been assigned in an ad hoc manner, resulting in a sub-optimal experiment design with a comparatively high variance of the estimates. Different scalar criteria of the covariance matrix, connected to A- and D-optimal experiment design, are considered and evaluated. The results indicate that the accuracy of the estimates can be greatly improved by the use of optimally placed sensors. The theoretical study has been verified by experiments. The presented results can be used to design experiments with improved accuracy of the estimates.
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| 6. |
- Zhou, Shengyang, et al.
(författare)
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Elastic Aerogels of Cellulose Nanofibers@Metal–Organic Frameworks for Thermal Insulation and Fire Retardancy
- 2020
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Ingår i: Nano-Micro Letters. - : Springer Science and Business Media LLC. - 2150-5551 .- 2311-6706. ; 12:9
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Tidskriftsartikel (refereegranskat)abstract
- Metal–organic frameworks (MOFs) with high microporosity and relatively high thermal stability are potential thermal insulation and flame-retardant materials. However, the difficulties in processing and shaping MOFs have largely hampered their applications in these areas. This study outlines the fabrication of hybrid CNF@MOF aerogels by a stepwise assembly approach involving the coating and cross-linking of cellulose nanofibers (CNFs) with continuous nanolayers of MOFs. The cross-linking gives the aerogels high mechanical strength but superelasticity (80% maximum recoverable strain, high specific compression modulus of ~ 200 MPa cm3 g−1, and specific stress of ~ 100 MPa cm3 g−1).The resultant lightweight aerogels have a cellular network structure and hierarchical porosity, which render the aerogels with relatively low thermal conductivity of ~ 40 mW m−1 K−1. The hydrophobic, thermally stable MOF nanolayers wrapped around the CNFs result in good moisture resistance and fire retardancy. This study demonstrates that MOFs can be used as efficient thermal insulation and flame-retardant materials. It presents a pathway for the design of thermally insulating, superelastic fire-retardant nanocomposites based on MOFs and nanocellulose.
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| 7. |
- da Costa, Marcus Vinicius Tavares, et al.
(författare)
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Prediction of loss of barrier properties in cracked thin coatings on polymer substrates subjected to tensile strain
- 2021
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 426
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Tidskriftsartikel (refereegranskat)abstract
- Thin brittle coatings on polymer films are a potentially useful material combination for food packaging applications. The brittle coatings inevitably risk cracking when the package is converted. This strain-induced cracking leads to a loss of the key barrier properties. In design of packaging materials, it would be useful to predict the loss of the oxygen transmission rate (OTR) as a function of the applied tensile strain, which are linked by the crack opening and crack spacing in the coating. Previous works have presented a model that predicts the effect of strain on the OTR in the presence of cracks in the coating. This work uses an improved numerical model based on finite element method (FEM) to predict the oxygen permeability more accurately, especially for thin coatings with high crack densities. The numerical predictions show reasonable correspondence with experimental results for SiOx coatings. These results as well as predictions for previously tested metal-oxide coated polymer films show a significant increase in OTR at crack onset, which suggests that efforts should be made to make the coatings more ductile with higher crack onset strains if the barrier performance should be maintained in converted packages. The quantitative link from deformation over the damage state to barrier properties indicate that mechanics could provide a tool to aid the design of improved food packages with retained barrier capacity.
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| 8. |
- Fontana, Enrico, et al.
(författare)
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Nominated procurement and the indirect control of nominated sub-suppliers: Evidence from the Sri Lankan apparel supply chain
- 2021
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Ingår i: Journal of Business Research. - : Elsevier BV. - 0148-2963 .- 1873-7978. ; 127, s. 179-192
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Tidskriftsartikel (refereegranskat)abstract
- This article describes and discusses nominated procurement as a means through which buyers select sub-suppliers to achieve sustainability compliance upstream in emerging economies' supply chains. Hence, it critically examines the ways buyers articulate nominated procurement and the unfolding supply chain consequences. Based on in-depth interviews and fieldwork in the Sri Lankan apparel supply chain, the findings indicate that buyers accomplish sustainability compliance among their sub-suppliers while prioritizing their own business agenda. In doing so, however, buyers perpetuate “suboptimal compliance” of raw material suppliers and “sandwiching” of direct suppliers as harmful consequences on the supply chain. These consequences link theoretically with commercial, geographical, compliance and extended-compliance pressure. This article contributes to the advancement of the Sustainable Supply Chain Management literature by theorizing about nominated procurement, direct and indirect pressure, and pointing to the supply chain consequences beyond achievements in sustainability compliance.
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| 9. |
- Irshad, Yasir, 1977-, et al.
(författare)
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System identification in a networked environment using second order statistical properties
- 2013
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Ingår i: Automatica. - : Elsevier BV. - 0005-1098 .- 1873-2836. ; 49:2, s. 652-659
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Tidskriftsartikel (refereegranskat)abstract
- System identification for networked control is considered. Due to the time-delays in the network, it can be difficult to work with a discrete-time model and a continuous-time model is therefore chosen. A covariance function based method that relies on the second order statistical properties of the output signal, where it is assumed that the input signal samples are from a discrete-time white noise sequence, is proposed for estimating the parameters. The method is easy to use since the actual time instants when new input signal levels are applied at the actuator do not have to be known. An analysis of the networked system and the effects of the time-delays is made, and the results of the analysis motivate and support the chosen approach. Numerical studies indicate that the method is robust to randomly distributed time-delays, packet drop-outs, and additive measurement noise.
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| 10. |
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