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| 2. |
- Bulla-Cruz, Lenin Alexander, et al.
(författare)
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Event-based road safety assessment : A novel approach towards risk microsimulation in roundabouts
- 2020
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Ingår i: Measurement: Journal of the International Measurement Confederation. - : Elsevier BV. - 0263-2241. ; 165
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Tidskriftsartikel (refereegranskat)abstract
- Conventional road accident risk is measured by the undesirable events/exposure ratio. Common exposure indicators are activity-based, so event-based exposure is needed to achieve event-based safety assessment. Furthermore, road safety simulation is a growing research field. The influence of some software parameters is still unknown. Besides, the use of simulation for exposure assessment is incipient. This paper aims to validate a preventive event-based risk indicator: traffic conflicts/encounters, extending to risk microsimulation by a novel procedure to identify encounters in VISSIM. We evaluated the safety of a roundabout by three independent methods: [i] Swedish Traffic Conflict Technique using T-Analyst tool, [ii] VISSIM/SSAM conflict analysis, and, [iii] exposure mapping using encounters. Findings show that, once calibrated the safety distance factor of VISSIM conflict areas at 0.5, we got a similar number of observed and simulated conflicts, similar severities and similar number of encounters, resulting in similar observed and simulated risk outcomes.
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| 3. |
- Awoyera, Paul O., et al.
(författare)
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Structural performance of fire-damaged concrete beams retrofitted using bamboo fiber laminates
- 2024
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Ingår i: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- Fire-induced damage is a serious threat to the structural integrity of reinforced concrete (RC) beams, necessitating an effective retrofitting strategy to restore and improve their performance. This study investigates the structural performance of fire-damaged RC beams retrofitted with bamboo fiber laminates. A comprehensive analysis was performed, incorporating degradation rules to quantify the effect of temperature on both the load-carrying capacity and ultimate deflection of the RC beams. Eight conventionally designed and reinforced RC beams were tested, with two serving as controls. The remaining six beams were tested in pairs at three different temperatures (400 ◦C, 600 ◦C, and 800 ◦C) for 2-h exposure, with one beam featuring the bamboo fiber laminates in each pair. The bamboo fiber laminates enhanced the load-carrying capacity and deflection of the fire-damaged beams when subjected to incremental loading until failure. The deflection was improved by 48.78% at 400 ◦C, restoring the load-carrying capacity to control levels. The load-carrying capacity was increased by 29.5% at 600 ◦C, while the deflection was restored by 39.37%. The load-carrying capacity was enhanced by 37% at 800 ◦C, while the deflection was improved by 4.83%. According to the findings, bamboo fiber laminate is a viable alternative to synthetic fibers for retrofitting fire-damaged beams.
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| 4. |
- Badenes, Borja, et al.
(författare)
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Development of advanced materials guided by numerical simulations to improve performance and cost-efficiency of borehole heat exchangers (BHEs)
- 2020
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Ingår i: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 201
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Tidskriftsartikel (refereegranskat)abstract
- One promising way to improve the efficiency of borehole heat exchangers (BHEs) in shallow geothermal applications is to enhance the thermal properties of the materials involved in its construction. Early attempts, such as using metal tubes in the 1980s or the utilization of thin–foil hoses, did not succeed in being adopted by the market for diverse reasons (cost, corrosion, fragility, etc…). In parallel, the optimization of pipe size, the use of double-U-tubes, thermally enhanced grout, etc. were able to bring the measure for the BHE efficiency, the borehole thermal resistance, from 0.20 to 0.15 K/(Wm) down to 0.08–0.06 K/(Wm) in the best solutions today. A further improvement cannot be expected without development of new, dedicated materials, combining the versatility of plastic like PE with an increased thermal conductivity that matches the respective properties of the rock and soil. This goal was included in the Strategic Research and Innovation Agenda of the European Technology Platform on Renewable Heating and Cooling in 2013. Within an EU supported project, both BHE pipes and grouting materials have been produced prototypically in small amounts, suitable for the first tests in the intended environment. The present work explains the research pathways envisaged and the resulting sensitivity analysis to highlight the influence of some of the most critical parameters that affect the overall performance of a GSHP system. The results have allowed guiding the real development of more efficient new advanced materials for different scenarios representative of different European regions. Finally the developed materials and their properties are discussed, including a comparative assessment about their compliance with reference material properties as currently seen in the BHE market. © 2020 The Author(s)
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| 5. |
- Javadi, Hossein, et al.
(författare)
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Laboratory and numerical study on innovative grouting materials applicable to borehole heat exchangers (BHE) and borehole thermal energy storage (BTES) systems
- 2022
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 194, s. 788-804
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a laboratory-scale prototype of a borehole field has been designed and built to assess various innovative grouting products in a fully controlled environment. Three novel grout formulations are developed and evaluated: enhanced grout, a mixture of enhanced grout and microencapsulated phase change material, and a mixture of enhanced grout and shape stabilized phase change material. The objective is to evaluate the enhancement in their thermal properties (i.e., thermal conductivity and thermal energy storage capacity) compared to those using a commercial reference grout. Besides, three-dimensional numerical modeling is performed to provide a better understanding of the heat transfer and phase transition inside and outside the grout columns and to study the capability of the developed grouts to be used in a borehole heat exchanger or as borehole thermal energy storage system. To the best of the authors' knowledge, there have been just a few numerical studies on using phase change materials inside borehole heat exchangers to assess thermal energy storage applications. The experimental and numerical results showed much higher efficiency of the grout developed with a high thermal conductivity than the reference grout in terms of heat transfer in both the grout column and the surrounding sand. Furthermore, the results indicated the noticeable influence of the microencapsulated phase change material's presence in the grout formulation in terms of heat absorption/storage during the phase transition (from solid to liquid). However, it is concluded that reengineering shape stabilized phase change material should be conducted to make it more appropriate for thermal energy storage applications.
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| 6. |
- Lindblad, Peter, et al.
(författare)
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CyanoFactory, a European consortium to develop technologies needed to advance cyanobacteria as chassis for production of chemicals and fuels
- 2019
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Ingår i: Algal Research. - : Elsevier. - 2211-9264. ; 41
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Forskningsöversikt (refereegranskat)abstract
- CyanoFactory, Design, construction and demonstration of solar biofuel production using novel (photo) synthetic cell factories, was an R&D project developed in response to the European Commission FP7-ENERGY-2012-1 call "Future Emerging Technologies" and the need for significant advances in both new science and technologies to convert solar energy into a fuel. CyanoFactory was an example of "purpose driven" research and development with identified scientific goals and creation of new technologies. The present overview highlights significant outcomes of the project, three years after its successful completion. The scientific progress of CyanoFactory involved: (i) development of a ToolBox for cyanobacterial synthetic biology; (ii) construction of DataWarehouse/Bioinformatics web-based capacities and functions; (iii) improvement of chassis growth, functionality and robustness; (iv) introduction of custom designed genetic constructs into cyanobacteria, (v) improvement of photosynthetic efficiency towards hydrogen production; (vi) biosafety mechanisms; (vii) analyses of the designed cyanobacterial cells to identify bottlenecks with suggestions on further improvements; (viii) metabolic modelling of engineered cells; (ix) development of an efficient laboratory scale photobioreactor unit; and (x) the assembly and experimental performance assessment of a larger (1350 L) outdoor flat panel photobioreactor system during two seasons. CyanoFactory - Custom design and purpose construction of microbial cells for the production of desired products using synthetic biology - aimed to go beyond conventional paths to pursue innovative and high impact goals. CyanoFactory brought together ten leading European partners (universities, research organizations and enterprises) with a common goal - to develop the future technologies in Synthetic biology and Advanced photobioreactors.
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| 7. |
- Olayil, Reshmi, et al.
(författare)
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A Brief Review on Effect of Nano fillers on Performance of Composites
- 2021
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Ingår i: 2nd International Conference on Materials, Manufacturing and Machining for Industry 4.0 (ICMMM-2020) 9<sup>th</sup>-10<sup>th</sup> October 2020, Bannari Amman Institute of Technology, Tamil Nadu, India. - : Institute of Physics (IOP).
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Konferensbidrag (refereegranskat)abstract
- The utilization of nano materials creates a huge impact on today's scenario in development of various products. One such type of nano material developing concept is the usage of nano fillers for making composite product. This review briefs about the development of various nano fillers and its types followed by the fabrication of various composite combinations along with various nano fillers also discussed in detail. The addition of these nano fillers as a reinforcement or matrix for the composite making creates a significant impact in the mechanical properties of the composites. Special focus is given in such a way that the nano filler dispersion in which way enhances the mechanical properties. Better bonding between the matrix and reinforcement only improves the property how the nano fillers behave in that aspect also discussed in this review. The dispersion of nano fillers in various polymer matrix composites also presented in the review. Tensile, Flexural and Impact property of the composites decides its usage in various structural applications and this review presents briefly how these properties varying with respect to various nano fillers. Further the nano filler performance on the thermal properties as well as its impact in various sectors such as automobile, biomedical, sports, and aerospace applications etc., also presented in this review paper.
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| 8. |
- Pandian, Antony Vimal Paul, et al.
(författare)
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Unsymmetricity effects on seismic performance of multi-story buildings
- 2024
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Ingår i: Discover Applied Sciences. - : Springer. - 3004-9261. ; 6:9
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Tidskriftsartikel (refereegranskat)abstract
- The unsymmetrical configurations in buildings lead to non-uniform distributions in their strength, mass, and stiffness, and they are consequently prone to damage during seismic hazards. In this study, the seismic performance of multi-story buildings with 5, 8, 10, and 12 stories of square, ‘L’, ‘T’, and ‘U’-shaped buildings have been investigated. The research deals with the variation of the natural time periods and how it affects the seismic performance of unsymmetrical multi-story buildings. The coupled and uncoupled equations of motion, based on the symmetricity of the buildings about both axes, were solved to obtain natural time periods that influence the spectral acceleration of the ground accelerations. Six important ground accelerations were considered. Nonlinear static analysis, such as pushover analysis, was also carried out on all the buildings. Comparisons were made on the seismic behavior of both the symmetrical and unsymmetrical structures. The results revealed that the spectral acceleration influences dynamic responses, such as base shear, base moment, base torsion, roof displacement, roof rotation, and story drifts of the buildings. Moreover, it was found that even though the ‘L’-shaped buildings are unsymmetrical about both axes, they are less vulnerable than the ‘T’ and ‘U’-shaped buildings, which are unsymmetrical about one axis.
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| 9. |
- Tobler, Michael, et al.
(författare)
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Convergent changes in the trophic ecology of extremophile fish occurring along replicated environmental gradients
- 2015
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Ingår i: Freshwater Biology. - : Wiley. - 0046-5070 .- 1365-2427. ; 60:4, s. 768-780
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Tidskriftsartikel (refereegranskat)abstract
- Divergent selection along environmental gradients connecting locally restricted extreme habitats and adjacent benign habitats can shape convergent evolution of traits involved in coping with physiochemical stressors and can drive speciation. At the same time, the presence of such stressors alters aspects of the biotic environment, including resource availability and competitive regimes. However, it remains unclear whether and how the ecology of populations occurring in both extreme and benign environments varies in a predictable fashion. We investigated the trophic ecology of live-bearing fishes of the genus Poecilia that have independently colonised multiple springs containing toxic hydrogen sulphide in southern Mexico. Sulphide spring fish are adapted to the unique environmental conditions and are reproductively isolated from ancestral populations in adjacent non-sulphidic habitats. We used gut content analyses to test whether colonisation of extreme habitats was accompanied by shifts of trophic resource use and expansions of trophic niche width. Furthermore, we tested whether dietary shifts were reflected in trophic morphology by comparing intestinal tract lengths among populations using both wild-caught and common garden-raised individuals. Gut content analyses revealed that fish inhabiting toxic springs expanded their trophic niche width and changed their dietary resource use from detritus and algae to sulphide bacteria and invertebrates. This dietary shift was paralleled by changes in intestinal tract morphology, whereby sulphide spring fish had shorter intestines than fish from adjacent non-sulphidic habitats. Analysis of common garden-raised fish indicated that morphological differences between sulphidic and non-sulphidic populations are at least in part due to genetic differentiation. Both patterns of trophic resource use and differentiation in trophic morphology were consistent across replicated pairs of sulphidic and non-sulphidic populations, although the magnitude of differentiation varied among river drainages. Our results suggest that colonisation of and adaptation to sulphide springs in southern Mexico was paralleled by convergent changes in trophic ecology. This highlights the complexity of environmental gradients and the necessity of considering multiple sources of selection when studying the evolution of complex phenotypes.
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| 10. |
- Ljunggren, Magnus, 1942
(författare)
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Vem var Lenin?
- 2021
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Ingår i: Kvartal. - 2003-6906. ; :2021-02-08
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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