8 research outputs found
Patching sulfur vacancies: A versatile approach for achieving ultrasensitive gas sensors based on transition metal dichalcogenides
No full textTransition metal dichalcogenides (TMDCs) garner significant attention for their potential to create high-performance gas sensors. Despite their favorable properties such as tunable bandgap, high carrier mobility, and large surface-to-volume ratio, the performance of TMDCs devices is compromised by sulfur vacancies, which reduce carrier mobility. To mitigate this issue, we propose a simple and universal approach for patching sulfur vacancies, wherein thiol groups are inserted to repair sulfur vacancies. The sulfur vacancy patching (SVP) approach is applied to fabricate a MoS2-based gas sensor using mechanical exfoliation and all-dry transfer methods, and the resulting 4-nitrothiophenol (4NTP) repaired molybdenum disulfide (4NTP-MoS2) is prepared via a sample solution process. Our results show that 4NTP-MoS2 exhibits higher response (increased by 200 %) to ppb-level NO2 with shorter response/recovery times (61/82 s) and better selectivity at 25 °C compared to pristine MoS2. Notably, the limit of detection (LOD) toward NO2 of 4NTP-MoS2 is 10 ppb. Kelvin probe force microscopy (KPFM) and density functional theory (DFT) reveal that the improved gas sensing performance is mainly attributed to the 4NTP-induced n-doping effect on MoS2 and the corresponding increment of surface absorption energy to NO2. Additionally, our 4NTP-induced SVP approach is universal for enhancing gas sensing properties of other TMDCs, such as MoSe2, WS2, and WSe2.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Bio-Electronic
Hydraulic Disturbance Method to Reduce the Pressure Fluctuation in Francis Turbine Draft Tube
No full textThermal Performance of New Hybrid Solar Energy-phase Change Storage-floor Radiant Heating System
No full textAbstractA new solar energy-phase change storage-floor radiant heating system is proposed to provide a comfort indoor environment in winter. In this study the proposed new system is applied in an office building in Urumqi in China. The system consists mainly of three units: evacuate heat pipe solar collectors (as heat collection unit), vertical phase change thermal energy storage device (VPCTESD) and floor radiant heating system. The influence on thermal efficiency of solar collector, inlet and outlet water temperature, connect method during local heating period and thermal performance of this system was developed experimentally. The results reported in this paper adequately support the new system as an alternative to the traditional solar heating system, and it can increase 30% utilization of solar energy than traditional solar heating system. The research result provides a reference for optimization design of this kind of system
Inversion of interlayer scale using dynamic data of production wells in bottom water reservoirs: Sangtamu Oilfield, Tarim basin
No full textAbstract The target reservoir is a typical blocky bottom water reservoir. There are several interlayers of varying scales inside it, which impact the characteristics of the oil production and water breakthrough curves of the wells in the water flooding development oilfield, resulting in strong heterogeneity within the reservoir. The Sangtamu Oilfield has an average well spacing of approximately 600 m, causing a challenge in accurately identifying the range of small-scale interlayer spreading. This, in addition, challenges the subsequent 3D geological modeling process. This paper proposes a method to accurately characterize the size of various interlayers in a reservoir by using production dynamics data from bottom water reservoirs to invert the interlayer scale. By classifying the water breakthrough curve styles derived from theoretical testing, the range of reservoir internal interlayer scales is compared and inverted based on the actual water breakthrough styles of wells in the Sangtamu oil field. In the process, many interlayer scales derived from various types of geologic data acquisition were combined to form a quantitative geologic knowledge database of interlayers that synthesizes both dynamic and static data. This method has been applied in the Tarim Basin’s Sangtamu Oilfield, where the reservoir numerical simulation history was used to fit the model. This resulted in an overall fitting coincidence rate of 96% in the Sangtamu Oilfield and a single-well fitting coincidence rate of over 90% in well LN14. This method offers a new viewpoint on characterizing the interlayer’s scale in the area of the non-dense well network
Climate change and water resources management - 4th Yangtze Forum
No full text1 The Swiss Strategy for Adaptation to Climate Change (Probst Thomas, Hohmann Roland, Koellner-Heck Pamela) 2 Adaptation to Water-Related Disasters Caused by Extreme Weather Conditions (Takara Kaoru) 3 The Application of Macro Scale Distributed Hydrological Model in Runoff Simulation of JiaLingJiang River Basin (Junliang Jin, Guoqing Wang, Cuishan Liu, Ruimin He) 4 Building with Nature: Sustainable Development in Times of Climate Change (Huib de Vriend) 5 The Swiss Water Management Strategy for Adaptation to Climate Change (Hugo Aschwanden, Schaedler Bruno) 6 Climate Change Adaptation-a New Area for River Basin Management (Lifeng Li) 7 Water Resources Outlook and Management for Climate Change in KOREA (Jin Hyeog PARK, Deuk Koo KOH, Gwang Man LEE, Hyo Sok CHAE) 8 Climate Change Impact on Water Resources in Changjiang River (Yan Huang, WenFa Yang, Li Chen) 9 Capacity Planning in a Nonstationary Climate (Neela P. Babu and Daniel P. Loucks) 10 New approaching addressing challenges in the coupling of atmosphere-land surface-hydrology processes: overview and opportunities (Zhongbo Yu, Yang Huang, Chuanguo Yang, Qin JU, Haishen Lu, Tao Yang, Zhenchun Hao, Yipilig Li, Xing Chen, Long Xiang) 11 Issues of Adaptation to Climate Change and Variability lnduced by Multi-Drives: A Case of Shanghai City (Guoyu Ren) 12 Monitoring and Early Warning of Glacier Lake Outburst Floods in the Varkant River Area under Conditions of Climate Change (Hess Josef, Keusen Hans Rudolf and Haemmig Christoph) 13 The UK Climate Change Risk Assessment: Analysis of the Water Sector (Hurford, A., Wade, S.O., Rance, J., Ramsbottom, D.) 14 Water Quality and Climate Change in Australia (Michael R Moore) 15 The Conception and Practice of the Water Resources Model of the Yangtze River Basin (Yan Huang, Ying Xiong, Hanggang Zhang, Mingxin Li) 16 Evaluation of the simulation performance of lPCC AR4 global elimate models on Huaihe River Basin (Zhenchun Hao, Qin Ju, Lu Wang, Weijuan Jiang) 17 The Impact of Climate Change on Water Resources of Hanjiang River Basin (Honggang Zhang, Shenglian Guo, Haijin Guo, Hua Chen) 18 Research on the Evaluation of Hydropower Clean Energy under the Low Carbon Economy (Dengzhong Zhao, Yongbo Chen, Xianjia Wang, Jingjiang Ran) 19 Enhancing Capacity construction of Water Quality Monitoring and Service to support the Strictest Water Resources Management (Yinping Dai) 20 The Function and Consideration of Hydrology in Carrying out the Strictest Water Resources Management (Lanjun LU) 21 A Study on lntegrated Regulation and the Maintenance of Environmental Flow of Downstream of Dam of Danjiangkou Reservoir (Guangyan Feng, Bin Xu) 21 Analysis on the Impact of Climate change on inflow to the Three Gorges Reservoir (Miaolin Wang, Baoxian Hou, Liang Zhang) 23 Analysis on the features of Pollution Souree of Danjiangkou Reservoir and corresponding protection measures (Feng Wang, Wenyao Zhao, Shuyong Li) 24 Variation trends of hydro-meteorological elements in Kuyehe River catchment during 1955\u972008 (Tang Fangfang, Wang Guoqing, Guo Chunqing, Niu Haijing) ============================================================== Speech at the Opening Ceremony of the 4th Yangtze Forum (Huang Lixin) Speech at the Opening Ceremony of the 4thYangtze Forum (Hu Siyi) Speech at the Opening Ceremony of the 4th Yangtze Forum (Deng Bentai) Speech at the Opening Ceremony of the 4th Yangtze Forum (Yin Hong) Speech at the Opening Ceremony of the 4thYangtze Forum (Markus Ederer) Speech at the Opening Ceremony of the 4th Yangtze Forum (Goetz Andreast) Science-based Supporttor Sustainable U se of Water Resources of Chin ( Hu Siyi) Accelerate Yangtze River Harnessing, Development and Protection for Coordinated Development of RegionalSocioeconomy (Cai Qihua) Lay Equal Stress on Exploitation, Management and Conservation to Promo te Balanced Development in the Areaalong the Yangtze River (Huang Lixin) Same Lessans from Multi Purpose Water Resources Management in the United States (Jeffrey J. Dorko) Recognition and Consideration for the Issues of Climate Change- Zhang Jianyun Spanish Experience in River Ba sin Planning- Integrated River Basin Management (Josep Puxeu Rocamora) Enhance Systematic Monitoring and Integrated Research of Estuary for Sustainable Development of Yangtze River Delta and Basin-wide (Shen Jun) Lay a Solid Foundation for Water Conservancy Accelerate the Development of Wanjiang Region (Zhao Shucong) Lead Ecological Construction through a Limpid Lake Realize New Rise unde Blue Sky and Clean Water (Hu Youtao) Improving the Environmental Flows for Harmony between Yangtze and Regional Development (Jim Gradoville) On Measures for Flood Control in the Middle Reaches of the Changjiang River (Guo Shenglian) Speed up Harnessing ofXiangjiang River and Dongting Lake and Promo te Green Rise of Hunan Province (Xu Minghua) Construction of Ecological Reservoir Area Realization of Sustainable Development (Ma Zhengqi ) Care for Our Mother River (Zhang Xingsheng) Grasp Opportunity to Construct Water Conservancy Projects on Large Scale Accelerate to Build Prosperous Water Resources Province (Zhong Mian) Promote Sustainable Economic and Social Development in Central Yunnan by Tapping Water Resources More Effectively Kong Chuizhu) Accelerate Water Conservancy Construction for a Prospective Tibet (Gersang Ciren ) Protection of the Three-river Sources as a Key Ecological Shelter of China (Deng Bentai
Cross-scale chip removal process analysis and optimization using hybrid CFD-DEM simulation
No full textDrilling is a critical process in the manufacturing of aerospace components, and the quality of drilled connection holes directly determines the service reliability of high-end equipment. During drilling, different materials produce chips of varying sizes (ranging from micrometers to millimeters), leading to issues such as high temperature and tool wear. Efficient removal of these multi-scale chips is essential for improving drilling quality. However, the narrow and complex internal structure of enclosed or semi-enclosed chip removal systems often result in inefficient chip evacuation. In addition, experimental observation of airflow and chip velocity within such system is challenging, hence numerical simulation of the chip removal process become a practical alternative. This study utilizes a hybrid approach combining CFD and DEM simulation (CFD-DEM) to systematically investigate the characteristics of cross-scale chip removal processes. Simulation results show that the diffused airflow and low/negative velocity flow regions of the existing system are unfavorable for chip removal. To address this issue, different eccentric designs and diversion holes were introduced, and their impacts on the chip removal performance have been evaluated. The results were then used to guide the optimization of the chip removal system. Through combined/optimized eccentric design and diversion hole design, the overall chip removal performance of the system shows a significant improvement (48.27%)
