Design of Balanced Reactor Welded with Water-Cooled Aluminum Busbars

A new process of welding aluminum water-cooled busbars is proposed, It can not only reduce the weight and cost, but also improve the dynamic and thermal stability. Furthermore~ both finite element method analysis and a prototype test testify the advantages of the design which is not limited by load current and provides a new approach for water-cooled reactors.

Analysis and optimization of heat loss for water-cooled furnace roller

A heat transfer model of furnace roller cooling process was established based on analysis of furnace roller＇s structure. The complicated model was solved with iteration planning algorithm based on Newton search. The model is proved logical and credible by comparing calculated results and measured data. Then, the relationship between water flow velocity, inlet water temperature, furnace temperature and roller cross section temperature, outlet water temperature, water temperature rise, cooling water heat absorption was studied. The conclusions and recommendations are mainly as follows： l） Cooling water temperature rise decreases with the increase of water flow velocity, but it has small relationship with inlet water temperature; 2） In order to get little water scale, inlet water temperature should be controlled below 30 ℃. 3） The cooling water flow velocity should be greater than critical velocity. The critical velocity is 0.07 m/s and water flow velocity should be controlled within 0.4-0.8 m/s. Within this velocity range, water cooling efficiency is high and water temperature rise is little. If cooling water velocity increases again, heat loss will increase, leading to energy wasting.

Numerical Simulation on Subcooled Boiling Heat Transfer Characteristics of Water-Cooled W/Cu Divertors

In order to realize safe and stable operation of a water-cooled W/Cu divertor under high heating condition,the exact knowledge of its subcooled boiling heat transfer characteristics under different design parameters is crucial.In this paper,subcooled boiling heat transfer in a water-cooled W/Cu divertor was numerically investigated based on computational fluid dynamic（CFD）.The boiling heat transfer was simulated based on the Euler homogeneous phase model,and local differences of liquid physical properties were considered under one-sided high heating conditions.The calculated wall temperature was in good agreement with experimental results,with the maximum error of 5%only.On this basis,the void fraction distribution,flow field and heat transfer coefficient（HTC）distribution were obtained.The effects of heat flux,inlet velocity and inlet temperature on temperature distribution and pressure drop of a water-cooled W/Cu divertor were also investigated.These results provide a valuable reference for the thermal-hydraulic design of a water-cooled W/Cu divertor.

Preparation of Al-Zn-Mg-Cu alloy semisolid slurry through a water-cooled serpentine pouring channel

The semisolid slurry of Al-Zn-Mg-Cu alloy was prepared through a self-designed water-cooled copper serpentine pouring channel(WSPC) machine. Influences of pouring temperature, the number of turns and the cooling water flow rate on the microstructure of the semisolid Al-Zn-Mg-Cu alloy slurry were investigated. The results show that the semisolid Al-Zn-Mg-Cu alloy slurry with satisfactory quality can be generated by the WSPC when the pouring temperature is in the range between 680 ℃ and 700 ℃. At a given pouring temperature, the average grain size of primary α-Al decreases and the shape factor increases with the increase of the number of turns. When the cooling water flow rate is 450 L·h^(-1), the obtained semisolid slurry is optimal. During the preparation of the semisolid Al-Zn-Mg-Cu alloy slurry with low superheat pouring, the alloy melt has mixed inhibition and convection flow characteristics by "self-stirring". When the alloy melt flows through the serpentine channel, the chilling effect of the inner wall of the channel, the convection and mixed inhibition of the alloy melt greatly promote the heterogeneous nucleation and grain segregation. This effect destroys the dendrite growth mode under traditional solidification conditions, and the primary nuclei gradually evolve into spherical or nearspherical grains.

Optimization of the Water-Cooled Structure for the Divertor Plates in EAST Based on an Orthogonal Theory

An orthogoual experimental scheme was designed for optimizing a water-cooled structure of the divertor plate. There were three influencing factors： the radius R of the water- cooled pipe, and the pipe spacing L1 and L3. The influence rule of different factors on the cooling effect and thermal stress of the plate were studied, for which the influence rank was respectively R 〉 L1 〉 L3 and L3 〉 R 〉 L1. The highest temperature value decreased when R and L1 increased~ and the maximum thermal stress value dropped when R, L1 and L3 increased. The final optimized results can be summarized as： R equals 6 mm or 7 mm, L1 equals 19 mm, and L3 equals 20 mm. Compared with the initial design, the highest temperature value had a small decline~ and the maximum thermal stress value dropped by 19~ to 24~. So it was not ideal to improve the cooling effect by optimizing the geometry sizes of the water-cooled structure, even worse than increasing the flow speed, but it was very effective for dropping the maximum thermal stress value. The orthogoaal experimental method reduces the number of experiments by 80%, and thus it is feasible and effective to optimize the water-cooled structure of the divertor plate with the orthogonal theory.

Analysis of surface cracking in water-cooled rolls and heat transfer between furnace chamber and rolls in a direct flame furnace

In the direct fired furnace of a continuous annealing line, seal rolls are susceptible to deformation that leads to surface defects of steel strips. According to failure analysis, the reasons include improper structural design and heat imbalance. An improved design has been proposed to reduce stress concentration and thermal radiation. A heat transfer model has been employed to determine the proper water flow rate for roll cooling. Industrial application proves that seal rolls with the new design has less deformation and longer service life.

Fully Immersing Water-Cooled Radial Slab Laser and its Incoherent Beam Combination

A novel scheme of fully immersing water cooling is proposed for a Nd：glass radial slab laser. The slab medium is entirely immersed in the circulating water Ailing the pumping cavity, which enables much lower temperature and reasonably smaller thermal gradient in the slab medium. The radial slab is symmetrically and synchronously pumped by eight flash lamps, and produces multi-output beams with a total energy of 469md. Incoherent beam combination property of the multi-output beams is also investigated. The approach suggested here provides a way of scaling the slab lasers to much higher output levels and also a convenience for beam combinations.

The Corrected Simulation Method of Critical Heat Flux Prediction for Water-Cooled Divertor Based on Euler Homogeneous Model

An accurate critical heat flux（CHF） prediction method is the key factor for realizing the steady-state operation of a water-cooled divertor that works under one-sided high heating flux conditions.An improved CHF prediction method based on Euler＇s homogeneous model for flow boiling combined with realizable k-ε model for single-phase flow is adopted in this paper in which time relaxation coefficients are corrected by the Hertz-Knudsen formula in order to improve the calculation accuracy of vapor-liquid conversion efficiency under high heating flux conditions.Moreover,local large differences of liquid physical properties due to the extreme nonuniform heating flux on cooling wall along the circumference direction are revised by formula IAPWSIF97.Therefore,this method can improve the calculation accuracy of heat and mass transfer between liquid phase and vapor phase in a CHF prediction simulation of water-cooled divertors under the one-sided high heating condition.An experimental example is simulated based on the improved and the uncorrected methods.The simulation results,such as temperature,void fraction and heat transfer coefficient,are analyzed to achieve the CHF prediction.The results show that the maximum error of CHF based on the improved method is 23.7%,while that of CHF based on uncorrected method is up to 188%,as compared with the experiment results of Ref.[12].Finally,this method is verified by comparison with the experimental data obtained by International Thermonuclear Experimental Reactor（ITER）,with a maximum error of 6% only.This method provides an efficient tool for the CHF prediction of water-cooled divertors.

A human-sensitive frequency band vibration isolator for heavy-duty truck seats

In this study,a human-sensitive frequency band vibration isolator(HFBVI)with quasi-zero stiffness(QZS)characteristics for heavy-duty truck seats is designed to improve the comfort of heavy-duty truck drivers on uneven roads.First,the analytical expressions for the force and displacement of the HFBVI are derived with the Lagrange equation and d'Alembert's principle,and are validated through the prototype restoring force testing.Second,the harmonic balance method(HBM)is used to obtain the dynamic responses under harmonic excitation,and further the influence of pre-stretching on the dynamic characteristics and transmissibility is discussed.Finally,the experimental prototype of the HFBVI is fabricated,and vibration experiments are conducted under harmonic excitation to verify the vibration isolation performance(VIP)of the proposed vibration isolator.The experimental results indicate that the HFBVI can effectively suppress the frequency band(4-8 Hz)to which the human body is sensitive to vertical vibration.In addition,under real random road spectrum excitation,the HFBVI can achieve low-frequency vibration isolation close to 2 Hz,providing new prospects for ensuring the health of heavy-duty truck drivers.

Creation and Development of Turbo-generators with Water-Cooled Stator and Rotor Windings in Shanghai Electrical Machinery Mfg Works

1. An Overview of Manufacture and Operation A turbine generator utilizing a new technology of electrical machinery industry, i.e. the windings of its stator and rotor all being inner water-cooled, was first successfully created in China and was known afterwards as a turbine generator with watercooled stator and rotor windings (Abbrev, TGWSR). The teachers from Zhejiang University came to Shanghai between

Design and Implementation of Library Seating Management System

The library seating management system is an important part of the library’s modern services. The system is based on the Spring and Spring Boot framework, and the system realizes a series of functions such as real-time query, reservation, and cancellation of seat resources, providing users with great convenience. With a simple operation, users can know the availability of seats in the library in real time and reserve them according to their needs. At the same time, the system also provides rich management functions, enabling administrators to easily configure and manage seat resources. The addition, deletion, modification and review of users, the generation of seats, the viewing of user usage records, and the addition or deletion of points for users’ usage can also be carried out. This not only improves the management efficiency, but also provides more scientific and accurate data support for the management of the library. The system not only optimizes the user experience, but also promotes the scientific management and efficient utilization of library resources, and provides strong support for the modern services of the library.

The Effect of Seated Baduanjin Exercise on Psychological State, Fatigue Symptoms, and Quality of Life in Maintenance Hemodialysis Patients

Objective:To evaluate the intervention effects of seated Baduanjin exercise on patients undergoing maintenance hemodialysis(MHD).Methods:A total of 108 MHD patients admitted between July 2022 and July 2023 were selected.They were randomly assigned into two groups:the experimental group,with 55 patients,who received seated Baduanjin exercise combined with leg exercises during dialysis;and the control group,with 53 patients,who only performed leg exercises during dialysis.The psychological state,fatigue symptoms,quality of life,and sleep quality scores were compared between the two groups,and exercise endurance was recorded.Results:After the intervention,the psychological state scores in the experimental group were lower than those in the control group,the fatigue symptom scores were lower,the quality of life scores were higher,the sleep quality scores were lower,and the exercise endurance was higher(P<0.05).Conclusion:Seated Baduanjin exercise can improve the negative psychological state and fatigue symptoms of MHD patients,enhance their quality of life and sleep quality,and effectively increase their exercise endurance.

TRAMO/SEATS在危机事件中对旅游影响研究的应用

国内外对旅游危机事件的研究集中于管理方面,近年相关热点转向对旅游影响的研究。以往定性研究多,从经济数量模型进行定量分析研究的较少。本文使用在经济金融领域使用广泛的ARIMA改进版——TRAMO/SEATS方法评估危机事件,如疾病、地震等突发事件对中国旅游业的影响。作为欧盟各国统计局主要统计方法,TRAMO/SEATS方法能够最大程度地反映旅游业季节性波动的特点。通过该方法对2003年在中国内地和香港地区爆发的SARS进行实证研究,分析评估该危机事件的长期影响。在此基础上提出,国家短期内应当通过提高产品质量和拓展高质量的细分市场实现旅游效益型增长;恢复后期才可以推出更为直接的促销手法实现旅游数量型增长,采取刺激旅游人数快速增长的政策和措施。

监管政策对商业银行行为选择的冲击效应研究——基于H省若干家商业银行的TRAMO/SEATS检验

根据《巴塞尔协议》等国际公约的要求,中国的银行监管部门于2004年1月开始,在全国的银行系统推行严格的资本充足性管理。作为国际银行界主流的监管政策,资本充足性管理对商业银行的行为选择产生了深远的影响。本文选取了中国中部某省份2002年至2006年的商业银行数据,针对包括贷款对象结构、贷款期限结构和风险偏好结构三个表征商业银行行为特征的24个数据序列,运用TRAMO/SEATS的技术方法,实证检验了所有序列的结构性变动点以及监管政策的冲击效果。研究显示,当监管当局开始实施严格的资本充足性监管时,大多数商业银行都降低了风险偏好,说明监管政策的冲击效应十分明显;但是经过大约一年后,几乎所有的商业银行又选择恢复到初始状态,开始增加风险偏好,说明存在商业银行的资本约束软化效应。因此,若要保持资本监管政策的长期效果,还需不断完善相关制度体系建设。本文从商业银行行为变化的特征出发,提出了我国应对《巴塞尔协议Ⅲ》挑战的若干建议。

基于频域的X-13ARIMA-SEATS季节调整过滤器诊断

本文从频域角度对X-13ARIMA-SEATS季节调整程序的对称和并行过滤器进行研究,考察不同的模型非季节和季节移动平均参数以及不同过滤器长度对平方增益函数和相位延迟函数的影响,并以中国采购经理人指数(PMI)和居民消费价格指数(CPI)季节序列诊断为例,从频域角度比较X-11和以ARIMA为基础的AMB方法的平方增益函数和相位延迟函数来选择更优的季节调整方法。研究结论为:(1)非季节移动平均参数增大时,两种过滤器平方增益函数有下降趋势,季节移动平均参数增大时,平方增益函数有上升趋势。长度较短的过滤器波动更剧烈,季节频率上波谷宽度更宽。(2)季节移动平均参数越大时,相位延迟函数震荡越剧烈,非季节移动平均参数越大时,季节频率上的相位延迟增大。单个非季节频率区间内相位延迟函数与平方增益函数有反向关系。(3)AMB方法在非季节频率区间上的增益函数比X-11方法更趋于1,过滤器的凹槽比X-11方法更窄,且频率分量的相位失真更小,在PMI季节调整中更好;X-11方法对称过滤器的平方增益函数更小且更趋于1,在非频率区间上的相位延迟函数比AMB方法更小,更适用CPI的季节调整。(4)与传统季节调整质量诊断相比,频域诊断在估计季节成分的稳定性和过滤器的延迟特性方面具有优势,在季节调整方法选择时可综合两方面的结论。

Simulation of the Interaction between Driver and Seat

Test is one of methods to acquire human-seat pressure distribution in driving, with the deficiency of being uneasy to obtain the stress information of soft tissue inside human body and the sheer force of interface between human and seat, which can be obtained by simulation. But current simulation method focuses mainly on calculation itself other than combining it with posture prediction and cab packaging parameters, which cause it difficult to acquire accurate pressure calculation results without accurate posture of human body, and make it almost meaningless to design optimization. Therefore, a human body geometric model with posture change capability is built and linked up with Cascade Prediction Model（CPM）, which takes cab packaging parameters as inputs. A detailed finite element model of driver human body is constructed and used to conduct the driver-seat interaction simulation between human body and seat. Good accordance of pressure distribution is observed between simulation and test, which validates the simulation. In addition to the distribution pattern, curves on key sections are used to analyze the pressure and shear stress on the seat surface, as well as soft tissue stress inside human body. The simulation shows that the maximum stress of buttocks locates under the ischial tuberosity, and the maximum stress of trunk occurs near the scapula posterior and the lower waist. These are the places where fatigue usually occurs. The maximum pressure of seat appears at the driver-seat contact area corresponding to the driver＇s maximum skin tissue stress. In order to guide the seat design and cab packaging and study the influence of posture to pressure distribution, finite element models for different levels of cab packaging parameters are created by using CPM. The pressure distributions are calculated and their tendencies varying with cab packaging parameters are obtained. The method presented provides a new way to accurately simulate the interaction between driver human body and seat, and to guide the seat design and cab packaging so as to improve seating comfort.

Finite Element Analysis of Contact Pressures between Seat Cushion and Human Buttock-Thigh Tissue

Unrelieved pressure on load-bearing muscle tissues of humans can produce pressure ulcers. In a seated upright posture, the highest pressures occur inferior to the ischial tuberosities (ITs). Moreover, the vibration can initiate the development of pressure ulcer. Therefore, the seat cushion is not only used to lower the maximum seating pressure on buttocks but also minimize the transmission of vibration to human body. The purpose of this study was to investigate the effects of varying vertical vibration frequencies on seat-interface contact pressure during sitting on three different seat cushions by using a finite element modeling approach. A simplified two-dimensional human buttock-thigh model was developed to simulate the mechanical response of the muscle of buttocks and thigh under vertical vibration. Static and vibrational loads with five different frequencies of 0.1, 1, 10, 30 and 50 Hz and the same amplitude of 3 mm were applied to different seat cushions. The result showed that the “SAF 6060” seat cushion with both hyperelastic and viscoelastic behaviors could be effective in reducing the amplitude of varying maximum contact pressure, especially for the frequency of 10-20 Hz. This method could help in design of seat cushions with appropriate material properties and shape so as to reduce vibrations transmitted to human body at a certain frequency range.

Retraction control of motorized seat belt system with linear state observer

A design and verification of linear state observers which estimate state information such as angular velocity and load torque for retraction control of the motorized seat belt (MSB) system were described. The motorized seat belt system provides functions to protect passengers and improve passenger's convenience. Each MSB function has its own required belt tension which is determined by the function's purpose. To realize the MSB functions, state information, such as seat belt winding velocity and seat belt tension are required. Using a linear state observer, the state information for MSB operations can be estimated without sensors. To design the linear state observer, the motorized seat belt system is analyzed and represented as a state space model which contains load torque as an augmented state. Based on the state space model, a linear state observer was designed and verified by experiments. Also, the retraction control of the MSB algorithm using linear state observer was designed and verified on the test bench. With the designed retraction control algorithm using the linear state observer, it is possible to realize various types of MSB functions.

Damping Collaborative Optimization of Five-suspensions for Driver-seat-cab Coupled System

Both the seat and cab system of truck play a vital role in ride comfort.The damping matching methods of the two systems are studied separately at present.However,the driver,seat,and cab system are one inseparable whole.In order to further improve ride comfort,the seat suspension is regarded as the fifth suspension of the cab,a new idea of ＂Five-suspensions＂ is proposed.Based on this idea,a 4 degree-of-freedom driver-seat-cab coupled system model is presented.Using the tested cab suspensions excitations as inputs and seat acceleration response as compared output,the simulation model is built.Taking optimal ride comfort as target,a new method of damping collaborative optimization for Five-suspensions is proposed.With a practical example of seat and cab system,the damping parameters are optimized and validated by simulation and bench test.The results show the seat vertical frequency-weighted RMS acceleration values tested for the un-optimized and optimized Five-suspensions are 0.50 m/s～2 and 0.39 m/s～2,respectively,with a decrease by 22.0%,which proves the model and method proposed are correct and reliable.The idea of ＂Five-suspensions＂ and the method proposed provide a reference for achieving global optimal damping matching of seat suspension and cab suspensions.

Optimization of Biodynamic Seated Human Models Using Genetic Algorithms

Many biodynamic models have been derived using trial and error curve-fitting technique, such that the error between the computed and measured biodynamic response functions is minimum. This study developed a biomechanical model of the human body in a sitting posture without backrest for evaluating the vibration transmissibility and dynamic response to vertical vibration direction. In describing the human body motion, a three biomechanical models are discussed (two models are 4-DOF and one model 7-DOF). Optimization software based on stochastic techniques search methods, Genetic Algorithms (GAs), is employed to determine the human model parameters imposing some limit constraints on the model parameters. In addition, an objective function is formulated comprising the sum of errors between the computed and actual values (experimental data). The studied functions are the driving-point mechanical impedance, apparent mass and seat- to-head transmissibility functions. The optimization process increased the average goodness of fit and the results of studied functions became much closer to the target values (Experimental data). From the optimized model, the resonant frequencies of the driver parts computed on the basis of biodynamic response functions are found to be within close bounds to that expected for the human body.