| 1. |
- Dalheim, M., et al.
(författare)
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Smart grid indicators for the Swedish regulatory authority for the implementation of the clean energy package
- 2020
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Ingår i: IET Conference Publications. - : Institution of Engineering and Technology. ; , s. 711-713
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Konferensbidrag (refereegranskat)abstract
- The Swedish Energy Markets Inspectorate (Ei) is an authority that is commissioned to strive for well-functioning energy markets. The EU directive 2019/944 contains requirements on the national regulatory authorities with respect to the system operators smart grid development that includes energy efficiency and the integration of distributed energy renewable. In addition, the member states should promote effective system operation. To assess smart grid development, it is important to identify indicators (both technical and economic) that objectively reflect the smart grid implementation in a Swedish context, that can be used in the regulatory context. This study contains the preliminary results of a feasibility study regarding smart grid indicators as a tool for assessment and supervision to reflect the smart grid development in Sweden.
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| 2. |
- Gross, A, et al.
(författare)
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Psychological Care, Patient Education, Orthotics, Ergonomics and Prevention Strategies for Neck Pain: A Systematic Overview : Update as part of the ICON* Project.
- 2013
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Ingår i: The Open Orthopaedics Journal. - : Bentham Science Publishers Ltd.. - 1874-3250. ; 7:Suppl 4:M12, s. 530-561
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Tidskriftsartikel (refereegranskat)abstract
- To conduct an overview on psychological interventions, orthoses, patient education, ergonomics, and 1⁰/2⁰ neck pain prevention for adults with acute-chronic neck pain.Search Strategy:Computerized databases and grey literature were searched (2006-2012).Selection Criteria:Systematic reviews of randomized controlled trials (RCTs) on pain, function/disability, global perceived effect, quality-of-life and patient satisfaction were retrieved.Data Collection & Analysis:Two independent authors selected articles, assessed risk of bias using AMSTAR tool and extracted data. The GRADE tool was used to evaluate the body of evidence and an external panel to provide critical review.Main Results:We retrieved 30 reviews (5-9 AMSTAR score) reporting on 75 RCTs with the following moderate GRADE evidence. For acute whiplash associated disorder (WAD), an education video in emergency rooms (1RCT, 405participants] favoured pain reduction at long-term follow-up thus helping 1 in 23 people [Standard Mean Difference: -0.44(95%CI: -0.66 to -0.23)). Use of a soft collar (2RCTs, 1278participants) was not beneficial in the long-term. For chronic neck pain, a mind-body intervention (2RCTs, 1 meta-analysis, 191participants) improved short-term pain/function in 1 of 4 or 6 participants. In workers, 2-minutes of daily scapula-thoracic endurance training (1RCT, 127participants) over 10 weeks was beneficial in 1 of 4 participants. A number of psychosocial interventions, workplace interventions, collar use and self-management educational strategies were not beneficial.Reviewers' Conclusions:Moderate evidence exists for quantifying beneficial and non-beneficial effects of a limited number of interventions for acute WAD and chronic neck pain. Larger trials with more rigorous controls need to target promising interventions
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| 3. |
- Wu, P., et al.
(författare)
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Interval Number-Based Safety Reasoning Method for Verification of Decentralized Power Systems in High-Speed Trains
- 2021
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Ingår i: Mathematical problems in engineering (Print). - : Hindawi Limited. - 1024-123X .- 1563-5147. ; 2021
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Tidskriftsartikel (refereegranskat)abstract
- Decentralized power systems are commonly used in high-speed trains. However, many parameters in decentralized power systems are uncertain and inevitably have errors. We present a reasoning method based on the interval numbers for decentralized power systems in high-speed trains. Uncertain parameters and their unavoidable errors are quantitatively described by interval numbers. We also define generalized linear equations with interval numbers (LAIs), which can be used to describe the movement of the train. Furthermore, it is proven that the zero sets of LAIs are convex. Therefore, the inside of the fault-tolerance area can be formed by their vertexes and edges and represented by linear inequalities. Consequently, we can judge whether the system is working properly by verifying that the current system state is in the fault-tolerance area. Finally, a fault-tolerance area is obtained, which can be determined by linear equations with an interval number, and we test the correctness of the fault-tolerance area through large-scale random test cases.
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| 4. |
- Yan, A., et al.
(författare)
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Hydraulic performance of a new district heating systems with distributed variable speed pumps
- 2013
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 112, s. 876-885
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Tidskriftsartikel (refereegranskat)abstract
- The application of distributed variable speed pumps (DVSP) in the district heating (DH) network has been considered as a technology improvement that has a potential of saving energy, compared to the conventional central circulating pump (CCCP) DH system. A hydraulic model was developed to simulate the hydraulic performance of such a DVSP DH system, based on Kirchhoff's laws. It was applied to a real DH network in Kuerle, China. In order to improve the model accuracy, a new parameter called resistance ratio was proposed by comparing the measured data and the simulated result. The validation result shows that the model has the ability to predict the hydraulic behavior of the DVSP system. The results show that when the rotational speeds of all substation pumps are synchronously decreased by the same percentage, the pump heads and the flow rates are also reduced synchronously and almost in the same degree in all loops. In addition, two operation cases of DH were investigated, including (I) the flow rate varies in all of the loops simultaneously, and (II) the flow rate varies only in one of the loops. For both cases, the DVSP system has a better performance of saving energy at least 30% than the CCCP system. Compared to the CCCP system, the installed pump capacities can be smaller in the DVSP system. Hence, applying DSVP, especially at a low flow rate, can save quite much electricity. Based on the example network in Kuerle, the DVSP system consumes electricity 71% and 31% less than the CCCP system for Cases I and II respectively.
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| 5. |
- Chen, Y., et al.
(författare)
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Theory-guided hard constraint projection (HCP) : A knowledge-based data-driven scientific machine learning method
- 2021
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Ingår i: Journal of Computational Physics. - : Academic Press Inc.. - 0021-9991 .- 1090-2716. ; 445
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Tidskriftsartikel (refereegranskat)abstract
- Machine learning models have been successfully used in many scientific and engineering fields. However, it remains difficult for a model to simultaneously utilize domain knowledge and experimental observation data. The application of knowledge-based symbolic artificial intelligence (AI) represented by expert systems is limited by the expressive ability of the model, and data-driven connectionism AI represented by neural networks is prone to produce predictions that might violate physical principles. In order to fully integrate domain knowledge with observations and make full use of the strong fitting ability of neural networks, this study proposes theory-guided hard constraint projection (HCP). This deep learning model converts physical constraints, such as governing equations, into a form that is easy to handle through discretization, and then implements hard constraint optimization through projection in a patch. Based on rigorous mathematical proofs, theory-guided HCP can ensure that model predictions strictly conform to physical mechanisms in the constraint patch. The training process of theory-guided HCP only needs a small amount of labeled data (sparse observation), and it can supervise the model by combining the coordinates (label-free data) with domain knowledge. The performance of the theory-guided HCP is verified by experiments based on a published heterogeneous subsurface flow problem. The experiments show that theory-guided HCP requires fewer data, and achieves higher prediction accuracy and stronger robustness to noisy observations, than the fully connected neural networks and soft constraint models. Furthermore, due to the application of domain knowledge, theory-guided HCP possesses the ability to extrapolate and can accurately predict points outside of the range of the training dataset.
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| 6. |
- Huang, C., et al.
(författare)
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Understanding the water-energy nexus in urban water supply systems with city features
- 2018
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Ingår i: CLEANER ENERGY FOR CLEANER CITIES. - : Elsevier. ; , s. 265-270
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Konferensbidrag (refereegranskat)abstract
- The water-energy nexus has been introduced into urban water supply systems (WSSs) to improve the current plight of scarce resources and greenhouse effect in recent years. Urban water-energy integrated management is limited by the characteristics and reality of each city. In this paper, we characterize the comprehensive influence factors of energy use in China urban WSSs including geographic differences and city forms. The results indicate that the pressure of pipeline network and plain area ratio restricted by geomorphology would significantly impact the energy consumption during conveyance and distribution stage. For the city form aspect, the total volume of urban water supply and the leakage rate of pipeline networks play important roles in energy consumption of urban WSSs in China. In this study, the specific electricity consumption in WSSs was quantified, and several factors affected by city features which show strong correlation with energy use were determined. The results are of great significance to the energy saving in water supply systems in urban areas.
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| 7. |
- Huang, J., et al.
(författare)
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Energy-efficient extraction of fuel from chlorella combined with CO2 capture
- 2014
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Ingår i: Energy Procedia. - : Elsevier BV. ; 61, s. 2805-2808
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Konferensbidrag (refereegranskat)abstract
- To combine the abilities of lipids extraction and CO2 capture by algae + IL system, chlorella hydrolysis integrating CO2 removal by ILs ([bmim][BF4], [bmim]Cl and [amim]Cl) to extract lipids energy-efficiently was demonstrated in this study. The addition of CO2 to [bmim][BF4] can increase the lipids yield from 14.2% to 15.6%. The value of net energy gain increased from 10.4 to 35.9 with the CO2 addition to [bmim][BF4] because of the compensated CO2 capture energy in the algae extraction process.
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| 8. |
- Huang, Q., et al.
(författare)
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Code tiling for improving the cache performance of PDE solvers
- 2003
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Ingår i: Proceedings of the International Conference on Parallel Processing. - 0769520170 ; , s. 615-624
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Konferensbidrag (refereegranskat)abstract
- For SOR-like PDE solvers, loop tiling either helps little in improving data locality or hurts their performance. We present a novel compiler technique called code tiling for generating fast tiled codes for these solvers on uniprocessors with a memory hierarchy. Code tiling combines loop tiling with a new array layout transformation called data tiling in such a way that a significant amount of cache misses that would otherwise be present in tiled codes are eliminated. Compared to nine existing loop tiling algorithms, our technique delivers impressive performance speedups (faster by factors of 1.55-2.62) and smooth performance curves across a range of problem sizes on representative machine architectures. The synergy of loop tiling and data tiling allows us to find a problem-size-independent tile size that minimises a cache miss objective function independently of the problem size parameters. This "one-size-fits-all" scheme makes our approach attractive for designing fast SOR solvers without having to generate a multitude of versions specialised for different problem sizes.
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| 9. |
- Huang, X., et al.
(författare)
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Experimental research and multi-physical modeling progress of Zinc-Nickel single flow battery : A critical review
- 2023
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Ingår i: Advances in Applied Energy. - : Elsevier Ltd. - 2666-7924. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical energy storage technologies hold great significance in the progression of renewable energy. Within this specific field, flow batteries have emerged as a crucial component, with Zinc–Nickel single flow batteries attracting attention due to their cost-effectiveness, safety, stability, and high energy density. This comprehensive review aims to thoroughly evaluate the key concerns and obstacles associated with this type of battery, including polarization loss, hydrogen evolution reaction, and dendrite growth, among others. Additionally, the study highlights ongoing research endeavors focused on addressing these concerns, such as optimizing battery operating conditions and developing new electrodes. Furthermore, recent advancements in experimental processes and multi-scale numerical simulations of Zinc–Nickel single flow batteries, facilitated by the visual literature analysis software VOSviewer, are also explored. The primary objective of this review is to acquire a comprehensive understanding of the electrochemical reaction and internal mass transfer mechanism of Zinc–Nickel single flow batteries, while also anticipating future research directions and prospects.
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