| 1. |
- Culverhouse, R. C., et al.
(författare)
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Collaborative meta-analysis finds no evidence of a strong interaction between stress and 5-HTTLPR genotype contributing to the development of depression
- 2018
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 23:1, s. 133-142
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Tidskriftsartikel (refereegranskat)abstract
- The hypothesis that the S allele of the 5-HTTLPR serotonin transporter promoter region is associated with increased risk of depression, but only in individuals exposed to stressful situations, has generated much interest, research and controversy since first proposed in 2003. Multiple meta-analyses combining results from heterogeneous analyses have not settled the issue. To determine the magnitude of the interaction and the conditions under which it might be observed, we performed new analyses on 31 data sets containing 38 802 European ancestry subjects genotyped for 5-HTTLPR and assessed for depression and childhood maltreatment or other stressful life events, and meta-analysed the results. Analyses targeted two stressors (narrow, broad) and two depression outcomes (current, lifetime). All groups that published on this topic prior to the initiation of our study and met the assessment and sample size criteria were invited to participate. Additional groups, identified by consortium members or self-identified in response to our protocol (published prior to the start of analysis) with qualifying unpublished data, were also invited to participate. A uniform data analysis script implementing the protocol was executed by each of the consortium members. Our findings do not support the interaction hypothesis. We found no subgroups or variable definitions for which an interaction between stress and 5-HTTLPR genotype was statistically significant. In contrast, our findings for the main effects of life stressors (strong risk factor) and 5-HTTLPR genotype (no impact on risk) are strikingly consistent across our contributing studies, the original study reporting the interaction and subsequent meta-analyses. Our conclusion is that if an interaction exists in which the S allele of 5-HTTLPR increases risk of depression only in stressed individuals, then it is not broadly generalisable, but must be of modest effect size and only observable in limited situations.
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| 2. |
- Lumley, Mark A., et al.
(författare)
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The Relationship of Chronic and Momentary Work Stress to Cardiac Reactivity in Female Managers : Feasibility of a Smart Phone-Assisted Assessment System
- 2014
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Ingår i: Psychosomatic Medicine. - : Lippincott Williams & Wilkins. - 0033-3174 .- 1534-7796. ; 76:7, s. 512-518
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To evaluate a wireless smart phone-assisted (SPA) system that assesses ongoing heart rate (HR) and HR-triggered participant reports of momentary stress when HR is elevated during daily life. This SPA system was used to determine the independent and interactive roles of chronic and momentary work stress on HR reactivity among female managers. Methods: A sample of 40 female managers reported their chronic work stress and wore the SPA system during a regular workday. They provided multiple reports of their momentary stress, both when triggered by increased HR and at random times. Relationships among chronic stress, momentary stress, and HR were analyzed with hierarchical linear modeling. Results: Both chronic work stress (b = 0.08, standard error [SE] = 0.03, p = .003) and momentary work stress (b = 1.25, SE = 0.62, p = .052) independently predicted greater HR reactivity, adjusting for baseline HR, age, smoking, caffeine, alcohol use, and momentary physical activity levels. More importantly, chronic and momentary stress significantly interacted (b = 1.00, SE = 0.04, p = .036); high momentary stress predicted elevated HR only in the context of high chronic stress. Conclusions: Female managers who experience chronic work stress displayed elevated cardiac reactivity during momentary stress at work. The joint assessment of chronic stress and momentary stress and their relationship to physiological functioning during work clarifies the potential health risks associated with work stress. Moreover, this wireless SPA system captures the immediate subjective context of individuals when physiological arousal occurs, which may lead to tailored stress management programs in the workplace.
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| 3. |
- Wang, Jinshan, et al.
(författare)
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POTENTIAL ENVIRONMENTAL BENEFITS OF FLUE GAS QUENCH INTEGRATION WITH EXISTING BIOMASS/WASTE-FUELLED CHP PLANT
- 2019
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Ingår i: Energy Proceedings. - : Scanditale AB.
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Konferensbidrag (refereegranskat)abstract
- Flue gas quench (FGQ) at advanced combined heat and power (CHP) plays a vital role by linking flue gas (FG) cleaning and wastewater treatment. In this paper, we have performed a detailed mass balance of pollutants in the flue gas and the process water with and without FGQ at a CHP plant. The results show that the system with FGQ puts less wastewater load (about 74 tonnes/day) together with less pollutant load on the municipal wastewater treatment plant (MWWTP) than the system without FGQ. Meanwhile, it results in fewer burdens on the external water use.
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| 4. |
- Wang, Y., et al.
(författare)
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Energy saving potential of using heat pipes for CPU cooling
- 2018
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311 .- 1873-5606. ; 143, s. 630-638
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Tidskriftsartikel (refereegranskat)abstract
- Air cooling is the most common cooling solution for central processing units (CPUs). However, the heat dissipation capacity of conventional air-cooled heatsinks is limited because of non-uniform temperature distribution in the base of heatsinks. Embedded heat pipes into the heatsink is an effective method to improve the heat dissipation of the CPU and make the temperature distribution of the heatsink base more uniform. This work studied the cooling performance of the heat pipe embedded heatsinks, including the surface temperature, the average temperature of base, the thermal resistance and the power consumption. The impact of the different arrangements of heat pipes on the temperature distribution was also investigated. Results show that to obtain the same CPU temperature, a lower air velocity was needed for the heatsink with embedded heat pipe at the same heat flux. The minimum thermal resistance of the studied heat pipe embedded heatsinks was 0.15 °C/W, which is lower than that of the reference conventional heatsink, 0.22 °C/W. In addition, the heatsink with H-shape arrangement of embedded heat pipes had the best overall performance, which cooling capacity was increased by 22.5% and the weight of the heatsink was reduced by 30.1% compared with the heatsink without heat pipes. The energy saving potential was also evaluated based on the measured real operating status of CPUs. The dynamic simulation results show that the total fan power consumption can be effectively reduced when using a heat pipe embedded heatsink to replace the conventional heatsink, which can be up to 66.2%.
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| 5. |
- Xu, J., et al.
(författare)
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Energy-water nexus analysis of wastewater treatment plants (WWTPs) in China based on statistical methodologies
- 2018
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Ingår i: CLEANER ENERGY FOR CLEANER CITIES. - : Elsevier. ; , s. 259-264, s. 259-264
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Konferensbidrag (refereegranskat)abstract
- Wastewater treatment plants (WWTPs) are considered as energy-intensive facilities. Against the background of stricter policy requirements and discharge standard, thousands of municipal WWTPs are experiencing upgrading and reconstruction in China. However, the accompanying energy consumption cannot be ignored. Based on the statistical analysis of energy consumption and relevant factors from data of more than six thousand WWTPs over China, in this paper we analyzed the most influential factors related to energy consumption, which include treatment technology, wastewater amount, removed pollutants, social and economic characteristics, etc. Furthermore, we set up systematic method of energy performance assessment for WWTPs and explored the potential of energy saving in WWTPs. Results showed that processing capacity, organic pollutant concentration, discharge standard and economic factors have major effects on energy efficiency. Although sludge treatment and disposal normally consume intensive energy, it is possible to recover energy from biomass in the sludge. The results indicate that there is huge potential for energy saving and recovery in WWTPs, and we propose a conceptual roadmap for energy efficiency improving in WWTPs in China.
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| 6. |
- Zou, X., et al.
(författare)
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Roadmap to urban energy internet : Techno-enviro-economic analysis of renewable electricity and natural gas integrated energy system
- 2022
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Ingår i: Journal of Cleaner Production. - : Elsevier Ltd. - 0959-6526 .- 1879-1786. ; 373
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Tidskriftsartikel (refereegranskat)abstract
- The integrated energy system which coordinates natural gas, renewable energy, and other energy subsystems is an effective way to promote a low-carbon economy. An effective framework for system assessment and optimisation is a critical issue. This paper takes a natural gas-wind-photovoltaic integrated energy system as the research object and uses the simulation software to analyse its techno-enviro-economic feasibility. Firstly, a mathematical model is customised to optimise the system installation and operation plans. Renewable electricity replaces some natural gas, resulting in pipeline pressure fluctuation. Here, the Stoner Pipeline Simulator software is used to simulate pipeline network operation to quantify the aforementioned pressure fluctuations. The proportion of renewable energy is gradually reduced until the network pressure fluctuation is less than 20% to ensure the stability of pipeline operation. Then, the optimal operation scheme can be determined. Taking three cities in Shandong, China, as cases, the results show that the proposed system is beneficial for urban energy internet development: (i) the total net present cost is reduced by 19.7%, 19.8%, and 20.8%, (ii) annual CO2 emission is reduced by 23.7%, 18.4%, and 12.2%; (iii) the levelised cost of energy is 0.142 $/kWh, 0.143$/kWh, and 0.153$/kWh.
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| 7. |
- Du, J., et al.
(författare)
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A theory-guided deep-learning method for predicting power generation of multi-region photovoltaic plants
- 2023
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Ingår i: Engineering applications of artificial intelligence. - : Elsevier Ltd. - 0952-1976 .- 1873-6769. ; 118
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Tidskriftsartikel (refereegranskat)abstract
- Recently, clean solar energy has aroused wide attention due to its excellent potential for electricity production. A highly accurate prediction of photovoltaic power generation (PVPG) is the basis of the production and transmission of electricity. However, the current works neglect the regional correlation characteristics of PVPG and few studies propose an effective framework by incorporating prior knowledge for more physically reasonable results. In this work, a hybrid deep learning framework is proposed for simultaneously capturing the spatial correlations among different regions and temporal dependency patterns with various importance. The scientific theory and domain knowledge are incorporated into the deep learning model to make the predicted results possess physical reasonability. Subsequently, the theory-guided and attention-based CNN-LSTM (TG-A-CNN-LSTM) is constructed for PVPG prediction. In the training process, data mismatch and boundary constraint are incorporated into the loss function, and the positive constraint is utilized to restrict the output of the model. After receiving the parameters of the neural network, a TG-A-CNN-LSTM model, whose predicted results obey the physical law, is constructed. A real energy system in five regions is used to verify the accuracy of the proposed model. The predicted results indicate that TG-A-CNN-LSTM can achieve higher precision of PVPG prediction than other prediction models, with RMSE being 11.07, MAE being 4.98, and R2 being 0.94, respectively. Moreover, the performance of prediction models with sparse data is tested to illustrate the stability and robustness of TG-A-CNN-LSTM.
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| 8. |
- Du, Y., et al.
(författare)
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Clustering heat users based on consumption data
- 2019
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Ingår i: Energy Procedia. - : Elsevier Ltd. - 1876-6102. ; , s. 3196-3201
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Konferensbidrag (refereegranskat)abstract
- In today's district heating (DH) energy market, it is common to use user functional categories in price models to determine the heat price. However, users in the same category do not necessarily have the same energy consumption patterns, which potentially leads to unfair prices and many other practical issues. Taking into account heat usage characteristics, this work proposes two data-driven methods to cluster DH users to identify similar usage patterns, using practical energy consumption data. Efforts are focused on extracting representative features of users from their daily usage profiles and duration curves, respectively. Employing clustering based on these features, the resulting typical usage patterns and user category distributions are discussed. Our results can serve as potential inputs for future energy price models, demand-side management, and load reshaping strategies.
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| 9. |
- He, W., et al.
(författare)
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Optimal Thermal Management Of Server Cooling System Based Cooling Tower Under Different Ambient Temperatures
- 2022
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Ingår i: Applied Thermal Engineering. - : Elsevier Ltd. - 1359-4311 .- 1873-5606. ; 207
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Tidskriftsartikel (refereegranskat)abstract
- To develop a highly efficient and energy-saving cooling system in a data center, this study investigates the optimal thermal management both on the internal server cooling cycle and external cold source water cycle under different ambient temperatures based on the principle of minimal power consumption. Taking a server cabinet of 4.8 kW as the case, an internal indirect water-cooled heat sink cycle and an external cooling tower cold source cycle are constructed. A hybrid thermal management model combined with a heat dissipation model and a power consumption model was developed with the aid of MATLAB and TRNSYS. Using this model, the relationship between the chip dissipation performance attached to the fin-type heat sink and the energy consumption performance of the cooling system under different water working conditions and ambient temperatures was analyzed. Finally, to achieve minimal system energy consumption, the optimized inlet temperature and water flow rates corresponding to different ambient temperatures were obtained by fitting expressions that can better serve the optimal design of data center cooling systems. Furthermore, when the optimal value was applied using the year-round temperature of Tianjin, China in the case study, a 21.3% reduction in power consumption and a 4.43% decrease in the power usage effectiveness can be achieved compared to the case without optimization. Therefore, significant power can be saved in a data center cooling system through thermal management optimization.
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| 10. |
- Huang, Q., et al.
(författare)
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Assessment of the arbitrage by a compressed CO2 energy storage system-based on dynamic characteristics
- 2024
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Ingår i: Journal of Energy Storage. - : Elsevier Ltd. - 2352-152X .- 2352-1538. ; 95
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Tidskriftsartikel (refereegranskat)abstract
- Fluctuations in electricity price create arbitrage opportunities for compressed CO2 energy storage (CCES) systems. However, previous studies often neglected the dynamic characteristics of CCES systems, leading to inaccurate assessments. This paper addresses this gap by evaluating the CCES system arbitrage considering its dynamic characteristics. We introduce a novel indicator, state of charge (SOC), into a mixed-integer linear programming (MILP) optimization model to capture the dynamics. Utilizing real electricity prices, the model optimizes the CCES operation strategy for a maximum profit. The results demonstrate that a CCES system with a 267 MWh capacity could achieve a total income of 22.5 MEUR in 2022, with a net present value (NPV) of 258.1 MEUR over 35 years, a payback time of 2 years, and an average round-trip efficiency (ARTE) of 77.0 %. Sensitivity analysis reveals that the sizes of the compressor, the expander, and the high-pressure gas tank significantly impact the arbitrage potential. In contrast, the steady-state model-based results demonstrate that the CCES system could yield a higher NPV of 573.7 MEUR, a shorter payback time of 1 year, and a higher ARTE of 87.0 %. This emphasizes the pivotal importance of integrating dynamic characteristics into the design and assessment of CCES systems for arbitrage assessment.
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