| 1. |
- Hägglund, Carl, 1975, et al.
(författare)
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Plasmonic Near-Field Absorbers for Ultrathin Solar Cells
- 2012
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Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 3:10, s. 1275-1285
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Forskningsöversikt (refereegranskat)abstract
- If the active layer of efficient solar cells could be made 100 times thinner than in today's thin film devices, their economic competitiveness would greatly benefit. However, conventional solar cell materials do not have the optical capability to allow for such thickness reductions without a substantial loss of light absorption. To address this challenge, the use of plasmon resonances in metal nanostructures to trap light and create charge carriers in a nearby semiconductor material is an interesting opportunity. In this Perspective, recent progress with regards to ultrathin (similar to 10 nm) plasmonic nanocomposites is reviewed. Their optimal internal geometry for plasmon near-field induced absorption is discussed, and a zero thickness effective medium representation is used to optimize stacks including an Al back reflector for photovoltaics. This shows that high conversion efficiencies (>20%) are possible even when taking surface scattering effects and thin passivating layers inserted between the metal and semiconductor into account.
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| 2. |
- Davidsson, Simon, et al.
(författare)
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A review of life cycle assessments on wind energy systems
- 2012
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Ingår i: The International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 0948-3349 .- 1614-7502. ; 17:6, s. 729-742
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Forskningsöversikt (refereegranskat)abstract
- PurposeSeveral life cycle assessments (LCA) of wind energy published in recent years are reviewed to identify methodological differences and underlying assumptions.MethodsA full comparative analysis of 12 studies were undertaken (10 peer-reviewed papers, 1 conference paper, 1 industry report) regarding six fundamental factors (methods used, energy use accounting, quantification of energy production, energy performance and primary energy, natural resources, and recycling). Each factor is discussed in detail to highlight strengths and shortcomings of various approaches.ResultsSeveral potential issues are found concerning the way LCA methods are used for assessing energy performance and environmental impact of wind energy, as well as dealing with natural resource use and depletion. The potential to evaluate natural resource use and depletion impacts from wind energy appears to be poorly exploited or elaborated on in the reviewed studies. Estimations of energy performance and environmental impacts are critically analyzed and found to differ significantly.Conclusions and recommendationsA continued discussion and development of LCA methodology for wind energy and other energy resources are encouraged. Efforts should be made to standardize methods and calculations. Inconsistent use of terminology and concepts among the analyzed studies are found and should be remedied. Different methods are generally used and the results are presented in diverse ways, making it hard to compare studies with each other, but also with other renewable energy sources.
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| 3. |
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| 4. |
- Fachrizal, Reza, 1993-, et al.
(författare)
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Smart charging of electric vehicles considering photovoltaic power production and electricity consumption : a review
- 2020
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Ingår i: eTransporation. - : Elsevier. - 2590-1168. ; 4
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Forskningsöversikt (refereegranskat)abstract
- Photovoltaics (PV) and electric vehicles (EVs) are two emerging technologies often considered as cornerstones in the energy and transportation systems of future sustainable cities. They both have to be integrated into the power systems and be operated together with already existing loads and generators and, often, into buildings, where they potentially impact the overall energy performance of the buildings. Thus, a high penetration of both PV and EVs poses new challenges. Understanding of the synergies between PV, EVs and existing electricity consumption is therefore required. Recent research has shown that smart charging of EVs could improve the synergy between PV, EVs and electricity consumption, leading to both technical and economic advantages. Considering the growing interest in this field, this review paper summarizes state-of-the-art studies of smart charging considering PV power production and electricity consumption. The main aspects of smart charging reviewed are objectives, configurations, algorithms and mathematical models. Various charging objectives, such as increasing PV utilization and reducing peak loads and charging cost, are reviewed in this paper. The different charging control configurations, i.e., centralized and distributed, along with various spatial configurations, e.g., houses and workplaces, are also discussed. After that, the commonly employed optimization techniques and rule-based algorithms for smart charging are reviewed. Further research should focus on finding optimal trade-offs between simplicity and performance of smart charging schemes in terms of control configuration, charging algorithms, as well as the inclusion of PV power and load forecast in order to make the schemes suitable for practical implementations.
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| 5. |
- Fuaad, Mariatul Rawdhah Ahmad, et al.
(författare)
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Microactuators technologies for biomedical applications
- 2023
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Ingår i: Microsystem Technologies. - : Springer Berlin/Heidelberg. - 0946-7076 .- 1432-1858. ; 29:7, s. 953-984
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Forskningsöversikt (refereegranskat)abstract
- Rapid advancements in technology have facilitated the development of functional micro-electromechanical system (MEMS) actuators. The use of such actuators has recently witnessed a surge in a variety of biomedical applications, owing to their high precision and conformity. This review aims to provide a comprehensive survey of the recently developed MEMS actuators and their use in biomedical applications. In the context of these applications, we discuss the most appropriate and extensively used actuation techniques such as thermo-responsive, magnetic, piezoelectric, and soft actuation. In addition, state-of-the-art biomedical systems, tools, and devices are categorically reviewed with recently utilized actuation techniques, to provide insight into the prospects of implementation. The key parameters responsible for the enhanced performance and efficiency of the actuators were also addressed. Finally, the future research trends in actuation techniques for biomedical applications are discussed.
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| 6. |
- Gu, Xiuquan, et al.
(författare)
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ZnO based heterojunctions and their application in environmental photocatalysis
- 2016
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 27:40
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Forskningsöversikt (refereegranskat)abstract
- As an alternative to TiO2 photocatalysts, ZnO exhibits a large potential for photocatalytic (PC) applications in environmental treatments, such as degradation of wastewater, sterilization of drinking water, and air cleaning. However, the efficiency achieved with ZnO to date is far from that expected for commercialization, due to rapid charge recombination, photo-corrosion as well as poor utilization of solar energy. Fortunately, in recent years, a great number of breakthroughs have been achieved in PC performance (including activity and stability) of micro-/ nano-structured ZnO by forming heterojunctions (HJs) with metal nanoparticles (NPs), carbon nanostructures and other semiconductors. In most cases, the improvement of PC performance was ascribed to the better charge separation at the interfaces between ZnO and the other components. Sometimes, the formation of hybrids is also in favor of visible light harvesting. This review summarizes recent advances in the fields of environmental photocatalysis by ZnO based HJs, and especially emphasizes their abilities in degradation of organic pollutants or harmful substances in water. We aim to reveal the mechanism underlying the enhanced PC performance by constructing HJs, and extend the potential of ZnO HJ photocatalysts for future trends, and practical, large-scale applications in environment-related fields.
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| 7. |
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| 8. |
- Xu, Chao, et al.
(författare)
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Microporous organic polymers as CO2 adsorbents : advances and challenges
- 2020
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Ingår i: Materials Today Advances. - : Elsevier BV. - 2590-0498. ; 6
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Forskningsöversikt (refereegranskat)abstract
- Microporous organic polymers (MOPs) with internal pores less than 2 nm have potential use in gas separation, sensing, and storage, in the form of membranes, monoliths, fibers, or adsorbent granules. These covalently bonded polymers are being formed by reacting with rigid organic monomers, and MOPs have lately been studied for capturing CO2 from gas mixtures in the form of membranes and adsorbents. Especially, the potential of MOPs in the processes of carbon capture and storage has been in the focus and small pore MOPs are preferred for regular separation processes but larger pores could be suitable if cryogenic processes would be used. Recent studies (2014 – mid 2019) on the potential use of MOPs as CO2 adsorbents and, to some degree, CO2-selective membranes are reviewed.
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| 9. |
- Aganovic, A., et al.
(författare)
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Ventilation design conditions associated with airborne bacteria levels within the wound area during surgical procedures: a systematic review
- 2021
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Ingår i: Journal of Hospital Infection. - : Elsevier BV. - 0195-6701 .- 1532-2939. ; 113, s. 85-95
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Forskningsöversikt (refereegranskat)abstract
- Background: Without confirmation of the ventilation design conditions (typology and airflow rate), the common practice of identifying unidirectional airflow (UDAF) systems as equivalent to ultra-clean air ventilation systems may be misleading, but also any claims about the ineffectiveness of UDAF systems should be doubted. The aim of this review was to assess and compare ventilation system design conditions for which ultra-clean air (mean <10 cfu/m ) within 50 cm from the wound has been reported. Six medical databases were systematically searched to identify and select studies reporting intraoperative airborne levels expressed as cfu/m close to the wound site, and ventilation system design conditions. Available data on confounding factors such as the number of persons present in the operating room, number of door openings, and clothing material were also included. Predictors for achieving mean airborne bacteria levels within <10 cfu/m were identified using a penalized multivariate logistic regression model. Twelve studies met the eligibility criteria and were included for analysis. UDAF systems considered had significantly higher air volume flows compared with turbulent ventilation (TV) systems considered. Ultra-clean environments were reported in all UDAF-ventilated (N = 7) rooms compared with four of 11 operating rooms equipped with TV. On multivariate analysis, the total number of air exchange rates (P=0.019; odds ratio (OR) 95% confidence interval (CI): 0.66–0.96) and type of clothing material (P=0.031; OR 95% CI: 0.01–0.71) were significantly associated with achieving mean levels of airborne bacteria <10 cfu/m . High-volume UDAF systems complying with DIN 1946-4:2008 standards for the airflow rate and ceiling diffuser size unconditionally achieve ultra-clean air close to the wound site. In conclusion, the studied articles demonstrate that high-volume UDAF systems perform as ultra-clean air systems and are superior to TV systems in reducing airborne bacteria levels close to the wound site. 3 3 3 3
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| 10. |
- Hjalmarsson, Johannes, et al.
(författare)
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Service stacking using energy storage systems for grid applications : A review
- 2023
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Ingår i: Journal of Energy Storage. - : Elsevier. - 2352-152X .- 2352-1538. ; 60
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Forskningsöversikt (refereegranskat)abstract
- Energy storage solutions for grid applications are becoming more common among grid owners, system operators and end-users. Storage systems are enablers of several possibilities and may provide efficient solutions to e.g., energy balancing, ancillary services as well as deferral of infrastructure investments. To ensure that an energy storage investment is guaranteed a reasonable payback period and a good return of investment it is advantageous to consider the possibility of service stacking. By offering additional services in turns or in parallel with the main service it is possible to create important revenue streams. The aim of this review is to provide an up-to-date status of service stacking using grid connected energy storage systems by presenting current research and on-the-table ideas. Results from the review show that frequency regulation services are the most common services to offer together with energy arbitrage and integration of renewable energy sources. The results also show that it is strategically favorable to offer additional services for storage units which are used seasonally or with low frequency. It can be concluded that service stacking is a promising method to implement for storage operators to increase the degree of utilization of storage units. It may also be concluded that the increased need for ancillary services increases the opportunity for storage units to participate in markets for energy and ancillary services. Future studies could focus on the correlation between service stacking possibilities and actual placement of the storage, and how hybrid storage configurations would affect the potential of service stacking.
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