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Perforated plate ventilation system and dynamics of infectious respiratory particle transmission

International Journal of Mechanical System Dynamics 2024年第4期4卷 497-514页

作者： Caiyue Song Mengmeng Cheng Benben Kong Zhuo Zeng Nenglin Yuan Hong Shi College of Energy&Power Engineering Jiangsu University of Science and TechnologyZhenjiangChina Key Laboratory of Aircraft Environment Control and Life Support MIITNanjing University of Aeronautics&AstronauticsNanjingChina

With the removal of indoor pollutants and the assurance of air quality emerging as critical research topics,the optimization of the internal environment in offices,where people stay for extended periods,is essential for controlling the spread of infectious respiratory *** movements of personnel and the operation of doors and windows within offices significantly impact the mechanisms of droplet transmission,warranting further *** study employs computational fluid dynamics simulations to explore the droplet dispersion characteristics and pollutant removal efficiency of the simplified model of perforated plate ventilation system(PPVS)(the diameter of the air supply openings has been reasonably simplified and uniformly set to 0.02 m)in office settings,as well as the impact of dynamic door operation scenarios on droplet spread and concentrations in breathing *** optimize the ventilation system's pollutant removal efficiency,airflow velocities(2.86,3.18,and 5.00m/s)are varied,with simulations conducted at the optimal velocity of 3.18 m/*** effects of continuous door operations,door-opening directions(towards the office and towards the isolation room),and opening speeds(π/4,π/6,π/8,andπ/10 rad/s)are also examined,revealing significant impacts on droplet *** indicate that PPVS effectively reduces indoor pollutant concentrations at all tested airflow velocities,with the optimal speed identified as 3.18 m/***,door-opening direction and speed can significantly influence droplet *** doors towards isolation rooms at smaller angles(less than 30°)effectively reduces droplet concentrations in personnel breathing zones,thereby mitigating the risk of droplet *** door-opening speeds also contribute to lower droplet concentrations in these *** innovative study explores the impacts of PPVS and dynamic door operation dynamics on droplet transmission during respiratory disease outbreaks,providing

关键词： dynamic simulation indoor pollutant infectious respiratory particles perforated plate ventilation system

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A Novel Cooperative MIMO Transmission Scheme Based on STBC for Event-Driven WSNs

A Novel Cooperative MIMO Transmission Scheme Based on STBC f...

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International Conference on Electronics technology (ICET)

作者： Li Jun Xie Wujun Aviation Key Laboratory of Science and Technology on Life-support Technology AVIC Aerospace Life-support Industries LTD. Xiangyang China

ISBN: (数字)9781728162836

ISBN: (纸本)9781728162843

The cooperative MIMO (CMIMO) technology having characteristics of low energy expended and high reliability can be very well suited to resource-constrained event-driven wireless sensor networks (WSNs), in which collecting date is unpredictable for space and time. A novel energy-efficient STBC-based CMIMO transmission scheme is put forward for event-driven WSNs in this letter, which adopts cross-layer design and dynamic event cluster. Detailed energy models are developed to maximize energy saving by the joint optimization for the number of cooperative nodes and constellation size. Through computer simulation, It can be found that the novel transmission scheme saves more energy in comparison with the traditional transmission protocol.

关键词： CMIMO event-driven WSNs energy-efficient STBC the joint optimization even-driven program space time block coding Energy efficiency transport protocols ENERGY MODELS multiple input multiple output systems

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Formation and speciation of disinfection byproducts during chlor(am)ination of aquarium seawater

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Journal of Environmental sciences 2015年第7期27卷 116-124页

作者： Haiting Zhang Huiyu Dong Craig Adams Zhimin Qiang Gang Luan Lei Wang Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Department of Civil and Environmental Engineering Utah State University Water Quality Analysis and Control Center Department of Life Support Equipments for Aquatic AnimalsBeijing Aquarium

The chemistry associated with the disinfection of aquarium seawater is more complicated than that of freshwater, therefore limited information is available on the formation and speciation of disinfection byproducts（DBPs） in marine aquaria. In this study, the effects of organic precursors, bromide（Br-） and pre-ozonation on the formation and speciation of several typical classes of DBPs, including trihalomethanes（THM4）, haloacetic acids（HAAs）,iodinated trihalomethanes（I-THMs）, and haloacetamides（HAc Ams）, were investigated during the chlorination/chloramination of aquarium seawater. Results indicate that with an increase in dissolved organic carbon concentration from 4.5 to 9.4 mg/L, the concentrations of THM4 and HAAs increased by 3.2-7.8 times under chlorination and by 1.1-2.3 times under chloramination. An increase in Br-concentration from 3 to 68 mg/L generally enhanced the formation of THM4, I-THMs and HAc Ams and increased the bromine substitution factors of all studied DBPs as well, whereas it impacted insignificantly on the yield of HAAs. Pre-ozonation with 1 mg/L O3 dose substantially reduced the formation of all studied DBPs in the subsequent chlorination and I-THMs in the subsequent chloramination. Because chloramination produces much lower amounts of DBPs than chlorination, it tends to be more suitable for disinfection of aquarium seawater.

关键词： Disinfection byproducts Chlorination Chloramination Pre-ozonation Bromine substitution factorAquarium seawater

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Numerical simulation of the water landing process of a light civil helicopter in level 5 sea conditions 2

Numerical simulation of the water landing process of a light...

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2023 2nd International Conference on Aerospace and Control Engineering, ICoACE 2023

作者： Zhu, Yuanchun Sun, Libing Emergency Rescue Technology R&D Department Hangyu Life-Saving Equipment Co. Ltd. Xiangyang441100 China Key Laboratory of Aviation Science and Technology for Aviation Protection and Lifesaving Technology Xiangyang441100 China

A helicopter emergency flotation system can provide flotation capability after the helicopter accidentally falls into the water. To solve the problem of attitude change of a helicopter after landing in water, a numerical simulation was carried out on a light civil helicopter with a weight of 3.5 t. It was simulated in level 5 sea conditions, the traveling speed was 15.4 m/s, and the height of the lowest point of the hydrostatic helicopter from the water surface was 250-260 mm, with or without lift, with or without floats. Landing on the water can be done with either basic or elliptical floats and in three different postures. The simulation results show that equipping a helicopter with pontoons can significantly improve its overturning resistance and flotation capabilities, but the impact on a helicopter equipped with pontoons will increase. Landing a helicopter in the water at a certain elevation angle is beneficial to the stability of the helicopter. A helicopter with a basic pontoon is more stable when it lands in the water. The performance is higher than that of the ellipsoidal pontoon, but the pitch stability of the basic pontoon is lower than that of the ellipsoidal pontoon. © Published under licence by IOP Publishing Ltd.

关键词： Helicopters

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Modeling and validation of key components of thermal management systems

Modeling and validation of key components of thermal managem...

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2024 CSAA/IET International Conference on Aircraft Utility Systems, AUS 2024

作者： Zekun, Mei Shuai, Xu Fanxin, Meng Guangya, Zhu Dalin, Zhang Weijian, Chen Key Laboratory of Aircraft Environment Control and Life Support MIIT Nanjing University of Aeronautics and Astronautics Nanjing China 805th Research Institute of China Aerospace Science and Technology Corporation Shanghai China Aviation Key Laboratory of Science and Technology on Aero Electromechanical System Integration No.33 Shuige Road Nanjing China

ISBN: (数字)9781837242108

In this paper, two key components of thermal management system are modeled by the underlying logic operation of SIMULINK. Simulink-PS signal conversion module is used to connect the electric grid and the calculation part of the heat grid to build the fuel tank heat grid model. The temperature transient simulation model of phase-change heat exchanger was established by using the integral module in Simulink library. Experimental verification and literature data verification are provided for these two components. The results show that the error between simulation results and experimental data is between 0.1% and 3%, which proves the accuracy and feasibility of the system modeling in this paper. It lays a foundation for the simulation of the overall thermal management scheme. © The Institution of Engineering & technology 2024.

关键词： Fuel tanks

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NUMERICAL SIMULATION AND EXPERIMENTAL RESEARCH ON TAYLOR COUETTE FLOW CHARACTERISTICS IN AIR GAP OF aviation MOTOR

NUMERICAL SIMULATION AND EXPERIMENTAL RESEARCH ON TAYLOR COU...

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2024 CSAA/IET International Conference on Aircraft Utility Systems, AUS 2024

作者： Ma, Hui Liang, Shuyue Zhan, Hongbo Qi, Lin Chen, Weijian Aviation Key Laboratory of Science and Technology on Aero Electromechanical System Integration No.33 Shuige Road Nanjing China Key Laboratory of Aircraft Environment Control and Life Support MIIT Nanjing University of Areonautics and Astronautics No.29 Yudao Street Nanjing China

A test bench with PIV technology was built and visualization research on Taylor vortex between concentric rotating cylinders was carried out to explore the flow morphology within the annular gap by changing the rotational speed of the inner cylinder. The numerical method and accuracy were verified by experiments. The selected turbulence model was then applied for numerical simulation of the Taylor Couette flow in a simplified air gap model of an aviation motor with smooth inner and outer walls. The Taylor Couette flow characteristics in the air gap under varying rotational speed were studied, and simulation results were given for flow with axial flow and without axial flow. © The Institution of Engineering & technology 2024.

关键词： Axial flow

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Research on measurement method of six degree of freedom for head based on safetr of aircraft pilot seat

Research on measurement method of six degree of freedom for ...

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CSAA/IET International Conference on Aircraft Utility Systems (AUS 2020)

作者： G. Luo Z. Jin W. Xie R. Wang Aviation Key Laboratory of Science and Technology on Life-support Technology Xiangyang Hubei China AVIC Aerospace Life-support Industries Ltd. China

In order to ensure the safety of the pilot's life, the six degree of freedom data of the ATD head need to be obtained through dynamic impact test to evaluate the possibility of head injury in the cockpit. A binocular photogrammetry method by the simplified solution of normal equation based on bundle adjustment was proposed. On the basis of satisfying the imaging requirements of high-speed cameras, the 3D position and posture data of the head were obtained by shooting and analyzing the images of the test process.

关键词： vehicle dynamics photogrammetry seats biomechanics impact testing injuries air safety stereo image processing pose estimation aircraft testing aerospace engineering dynamic testing

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Downregulation of forkhead box O1 (FOXO1) acetylation ameliorates cognitive dysfunction by inhibiting endoplasmic reticulum stress-regulated neuronal apoptosis in APP/PS1 transgenic mice

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Neuroprotection 2025年第0期

作者： Zhang, Nan Zhao, Zongyuan Chen, Xiaoxiao Yao, Hanbing Zhu, Min Ma, Shuqing Wang, Hui Yin, Xianghong Zhou, Ying Zheng, Chenfei Li, Jianmin Pan, Jingye Wang, Kaicheng Yang, Bin Wang, Yunting Fan, Junming Gong, Yongsheng Liu, Rong Zeng, Jing Fan, Xiaofang Shentu, Yangping School of Basic Medical Sciences Institute of Hypoxia Medicine Wenzhou Medical University Zhejiang Wenzhou China Wenzhou Medical University Zhejiang Wenzhou China Department of Pathology The First Affiliated Hospital of Wenzhou Medical University Zhejiang Wenzhou China Department of Nephrology The First Affiliated Hospital of Wenzhou Medical University Zhejiang Wenzhou China Key Laboratory of Intelligent Treatment and Life Support for Critical Diseases of Zhejiang Province Zhejiang Wenzhou China Department of Intensive Care Unit The First Affiliated Hospital of Wenzhou Medical University Zhejiang Wenzhou China Wenzhou Key Laboratory of Critical Care and Artificial Intelligence Zhejiang Wenzhou China Department of Laboratory Medicine West China Hospital Sichuan University Sichuan Chengdu China Department of Pharmacological and Pharmaceutical Sciences College of Pharmacy University of Houston Houston TX United States Department of Pathophysiology Key Laboratory of Ministry of Education for Neurological Disorders School of Basic Medicine Tongji Medical College Huazhong University of Science and Technology Hubei Wuhan China Key Laboratory of Alzheimer's Disease of Zhejiang Province Zhejiang Wenzhou China Zhejiang Key Laboratory of Intelligent Cancer Biomarker Discovery and Translation First Affiliated Hospital Wenzhou Medical University Zhejiang Wenzhou China Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province The First Affiliated Hospital of Wenzhou Medical University Zhejiang Wenzhou China

Background: Alzheimer's disease (AD) is a neurodegenerative disorder that affects the central nervous system. Silent information regulator sirtuin 1 (SIRT1) may deacetylate and suppress forkhead box O (FOXO) activities to promote neuronal survival. FOXO1 is involved in the regulation of metabolism, senescence, stress response, and apoptosis. Moreover, endoplasmic reticulum stress (ERS) mediates cell apoptosis. Therefore, this study aimed to determine whether the downregulation of SIRT1 expression exacerbates cognitive dysfunction by activating FOXO1 acetylation and promoting ERS-mediated apoptosis in amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice. Methods: We used APP/PS1 transgenic mice to construct an in vivo AD model. Additionally, we used β-amyloid (Aβ)-incubated HT22 cells and primary neurons (PNs) for in vitro analyses. Cognitive function was assessed using novel object recognition, the Morris water maze, and fear conditioning. Discrepancies between wild-type (WT) and APP/PS1 transgenic mice were evaluated using an unpaired t test. In addition, one-way analysis of variance was conducted for behavioral assessments and other tests involving four distinct groups, followed by a Tukey's honestly significant difference test for post hoc pairwise comparisons. Results: The expression of SIRT1 was downregulated (in animal experiments, WT mice vs. APP/PS1 mice, n = 3, p = 0.002;in cell experiments, HT22 cells vs. HT22 cells + Aβ_1–42, n = 3, p = 0.001;primary neurons vs. primary neurons + Aβ₁₋₄₂, n = 3, p < 0.001), whereas FOXO1 acetylation was upregulated both in vivo and in vitro (in animal experiments, WT mice vs. APP/PS1 mice, n = 3, p < 0.001;in cell experiments, HT22 cells vs. HT22 cells + Aβ₁₋₄₂, n = 3, p = 0.004;primary neurons vs. primary neurons + Aβ_1–42, n = 3, p < 0.001), leading to cognitive dysfunction, Aβ plaque deposition, and neuronal apoptosis. Quercetin, a SIRT1 agonist, reversed these chang

关键词： acetylation Alzheimer's disease endoplasmic reticulum stress forkhead box protein O1 neuronal apoptosis sirtuin 1

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Strength performance simulation and testing of pontoon component cabin 2

Strength performance simulation and testing of pontoon compo...

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2023 2nd International Conference on Aerospace and Control Engineering, ICoACE 2023

作者： Yang, Li Sun, Libing Zhu, Yuanchun Feng, Zhijie Zhang, Dongxiao Emergency Rescue Technology R&D Department Hangyu Life-Saving Equipment Co. Ltd. Hubei Xiangyang441100 China Key Laboratory of Aviation Science and Technology for Aviation Protection and Lifesaving Technology Hubei Xiangyang441100 China

The helicopter emergency flotation system consists of a buoy installation mechanism, a high-pressure gas bottle, and an electronic control starting device. The buoy assembly cabin is an important part of the buoy installation mechanism. During the flotation test, openings and cracks appeared in the pontoon assembly cabin due to insufficient strength. To avoid the occurrence of openings and cracks, methods such as rounding corners at the locations of openings and cracks, carbon fiber cross-laying technology, and changing cross-sections at stress concentration locations are adopted. The improved method was applied to the buoy cabin of the emergency flotation system, and the damage coefficient in the front and back states was simulated. The simulation results showed that the damage coefficient was reduced by 59%. After the improved cabin was subjected to the emergency flotation system flotation test, the openings and cracks in the pontoon assembly cabin disappeared, indicating that the improvement method was effective and could improve the strength and performance of the cabin. © Published under licence by IOP Publishing Ltd.

关键词： Flotation

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Reliability Analysis of Certain Rocket Engine Based on Fault Tree

Reliability Analysis of Certain Rocket Engine Based on Fault...

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作者： Wensheng Wang Liying Jin Xi Sun Jing Liu Aviation Key Laboratory Science and Technology on Life-Support Technology Aerospace Life-Support Industries Ltd. School of Mechanical Engineering Xi'an Jiaotong University

In this paper, a fault tree model of certain rocket engine is established according to its structure and working principle. Through qualitative analysis and quantitative calculation, the factors affecting the reliability of a certain type of rocket engine are obtained, and the corresponding improvement measures are put forward to improve the reliability and safety of a certain type of rocket engine.

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