scholarly journals Field Test Research and Numerical Simulation on Aerodynamic Deloading Characteristics of V-Shaped Noise Barrier

2019 ◽  
Vol 24 (4) ◽  
pp. 764-773
Author(s):  
Ji Zhao ◽  
Ning Zhi ◽  
Lu Ming
Keyword(s):  
Numerical Simulation ◽  
Impact Strength ◽  
Field Test ◽  
High Speed ◽  
Rapid Development ◽  
Research Work ◽  
Load Shedding ◽  
Aerodynamic Load ◽  
Noise Barrier ◽  
The Impact

With the rapid development of the high-speed railway in China, the problems of the noise pollution induced by passing trains emerge. Theoretically, the V-shaped noise barrier is of pretty good performance of noise-reduction and load-shedding. To assess the practical aerodynamic deloading characteristics of the V-shaped noise barrier, a full-scale field test was carried out at three measuring-sections equipped with noise barriers of different heights. In order to quantify the research work, the impact strength and deloading rate were selected as indicators. The effects of train speeds, train types and barrier heights are studied. This study includes the variations of impact strength and deloading rate in vertical directions. Meanwhile, 2D numerical simulation research is conducted to analyze the experimental results from the angle of mechanism. It is observed that the aerodynamic load acting on the surface of the V-shaped noise barrier was weaker and more uniform compared with conventional barrier. The flow field distribution influenced the deloading characteristics of the V-shaped noise barrier significantly. Moreover, the load-shedding effect of V-shaped noise barrier, when CRH380AM passed by, was slightly better than CRH380A. The deloading rate improved with the increasing of the noise barrier height in general.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

scholarly journals Numerical simulation and experimental research of cavitation nozzle based on equation curve

2021 ◽  
Author(s):  
Lifu Wang ◽  
Dongyan Shi ◽  
Zhixun Yang ◽  
Guangliang Li ◽  
Chunlong Ma ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Flow Field ◽  
High Speed ◽  
Quadratic Equation ◽  
Outer Contour ◽  
Study Results ◽  
Fluent Software ◽  
The Impact ◽  
Better Than

Abstract To further investigate and improve the cleaning ability of the cavitation nozzle, this paper proposes a new model that is based on the Helmholtz nozzle and with the quadratic equation curve as the outer contour of the cavitation chamber. First, the numerical simulation of the flow field in the nozzle chamber was conducted using FLUENT software to analyze and compare the impact of the curve parameters and Reynolds number on the cleaning effect. Next, the flow field was captured by a high-speed camera in order to study the cavitation cycle and evolution process. Then, experiments were performed to compare the cleaning effect of the new nozzle with that of the Helmholtz nozzle. The study results demonstrate that effective cavitation does not occur when the diameter of the cavitation chamber is too large. For the new nozzle, with the increase of the Reynolds number, the degree of cavitation in the chamber first increases and then decreases; the cleaning effect is much better than that of a traditional Helmholtz nozzle under the same conditions; the nozzle has the best cleaning effect for the stand-off distance of 300 mm.

Structure-property relationship of biodegradable poly(butylene succinate)/polycaprolactone coated inorganic particle composites

2013 ◽  
Vol 33 (2) ◽  
pp. 111-119
Author(s):  
Yiming Liu ◽  
Qing Liu ◽  
Bing Meng ◽  
Zhihua Wu
Keyword(s):  
Impact Strength ◽  
High Speed ◽  
Complex Viscosity ◽  
Structure Property ◽  
Scanning Calorimetry ◽  
Butylene Succinate ◽  
Elongation At Break ◽  
Inorganic Particle ◽  
Biodegradable Poly ◽  
The Impact

Abstract Polycaprolactone (PCL)-coated micro kaolin and nano-titania were prepared by high-speed hybrid mechanical coating. Poly(butylene succinate) (PBS)-coated inorganic particle composites were prepared by the melt-blending process. The influence of coated kaolin microparticles on the dynamic rheological behavior, non-isothermal crystallization behavior, micromorphology, and mechanical behavior were investigated. The effect of coated nano-titania on the mechanical properties of PBS-coated kaolin composites was also studied. A dynamic rheological property indicates that the complex viscosity of PBS-coated kaolin microcomposites is higher than neat PBS. Differential scanning calorimetry (DSC) implies that the micrometric size of kaolin particles restrains the crystallization of PBS. Scanning electronic microscopy (SEM) reveals a well dispersed state of coated kaolin in the polymer matrix. The impact strength of PBS-coated kaolin microcomposites is improved, while the tensile strength and elongation at break is decreased, but still appreciable. The introduction of coated nano-titania improves the impact strength dramatically, and the elongation at break of composites is considerable.

scholarly journals INFLUENCE OF FIRE PARTITIONS FOR SPEED FIRE DISTRIBUTION IN CLOSED PREMISES OF PRODUCTION AND STORAGE FACILITIES

Fire Safety ◽  
2021 ◽  
Vol 37 ◽  
pp. 44-51
Author(s):  
E. Hulida ◽  
V. Sharуу
Keyword(s):  
Fire Protection ◽  
Rapid Development ◽  
Research Work ◽  
Experimental Studies ◽  
Fire Spread ◽  
Building Structures ◽  
Fire Load ◽  
The Impact ◽  
And Storage ◽  
Storage Facilities

Introduction. Fires in closed premises of production and storage facilities are the most dangerous, because they hold large areas with a significant fire load. The current direction of providing a fire safety system at production and storage facilities in closed premises is to eliminate the conditions of the rapid development of fire and minimizing its effect through the use of fire curtains. This method of fire protection is practically not used in closed premises of production and storage facilities at the present stage. In most cases, fire partitions are used in such situations. Therefore, a topic issue today is the research of limiting the development of fires with the use of fire partitions and minimizing fire effects.Purpose. Investigate the process of spreading the fire in closed premises of production and storage facilities by using fire partitions to limit the speed of fire spread. Problem statement and solution. The following tasks must be solved to provide fire protection of production and storage facilities:1. to investigate the process of fire spread in closed premises of production and storage facilities without the use of fire partitions;2. to investigate the impact of fire partitions use on fire rate.Two possible modes of development fire in the premises are considered to solve the first problem: 1) with the presence of sufficient air (oxygen), with fire occurred in regulated fire load; 2) with insufficient air (oxygen), with fire occurred in regulated ventilation.It is necessary to choose the material and fire partition design accordingly to solve the second problem. The results of experimental studies [11] showed that fire partitions vermiculite-silicate plates can be used for various building structures manufacturing. Closed production and storage facilities structure analysis showed that these premises are constructed in most cases with a grid of columns 9Х12 m.Conclusions and proposals:1) There is only the first mode of fire with sufficient oxygen (air) in closed premises of production and storage facilities with a total area of more than 5000 m2 in the process of fire. The fire that occurred is regulated only by the fire load.2) The use of fire partitions between sections of the premises of production and storage facilities reduces the probability of fire spreading in the premises by about 3 times.3) It is necessary to continue research work in this direction to obtain more significant results of the process of development and spread of fire in the premises of production and storage facilities.

scholarly journals 5G Radiation and Potential Risks to the Environment and Human Health

2021 ◽  
Vol 12 (6) ◽  
pp. 1689-1693
Author(s):  
Hasan J. Hasan, Ali J. Yosef, Haider Abed Hachem
Keyword(s):  
Human Health ◽  
High Speed ◽  
Rapid Development ◽  
Health And Safety ◽  
Radio Spectrum ◽  
The Public ◽  
Potential Risks ◽  
Public Exposure ◽  
New Generation ◽  
The Impact

      The rapid development in wireless communication technology and the urgent need to develop it has led to an increase in the public exposure to more radio spectrum frequencies. The mountain increases in terms of the damage caused by these wireless technologies for the 2G, 3G and 4G generations ending with the new technique, which is 5G. As a result of the urgent need for fast communications and wide packages of data, only a new generation of communications has emerged, which is 5G, which enjoys high speed and broadcasts in short waves and high frequency. There is great concern about the impact of these technologies on human health and safety. This technique works at relatively higher frequencies than the previously used technologies. This research sheds light on some of the expected harms of these technologies and the result of using these techniques, where the damages on the human body in general, the skin and the human eye in particular, are addressed, as well as their impact on the environment and plants in general.

Study on Vertical Earth Pressure of Slab Culvert under High Embankment

2012 ◽  
Vol 256-259 ◽  
pp. 1898-1902 ◽  
Author(s):  
Bao Kuan Ning ◽  
He Fan ◽  
Lei Gong ◽  
Guo Qing Liu
Keyword(s):  
Numerical Simulation ◽  
Boundary Conditions ◽  
Field Test ◽  
Structural Design ◽  
Earth Pressure ◽  
Test Results ◽  
Soil Pressure ◽  
Vertical Earth Pressure ◽  
The Impact ◽  
Good Agreement

With the increasing of embankment culvert engineering applications, there has been due in part to the structural design is too conservative and not economic or select unreasonable structural form, leading to the phenomenon of cracking or even collapse of the culvert structure, and the phenomenon has seriously affected the normal use of the highway. In this paper, the numerical simulation of vertical earth pressure distribution on different structural forms of embankment on culverts, to discuss the impact of boundary conditions, fill height, the thickness of the culvert culverts vertical earth pressure. Combined with Heda highway a culvert covert field test results and numerical simulation results were compared and analyzed. The results show that the numerical simulation and field test results in good agreement with the culvert structure in the form of vertical earth pressure of the embankment culverts have a greater impact; the structure of different forms of the culvert in the upper soil pressure is significantly different. In addition, analysis of the impact of boundary conditions, filling height of culvert vertical earth pressure values. The results can reference for the study of the structural design of the embankment culverts security.

Simulation Research on Resistive Coupling of High-Speed Railway

2014 ◽  
Vol 496-500 ◽  
pp. 1036-1040
Author(s):  
Yao Dan Chi ◽  
Tian Hong Tan ◽  
Kai Yu Yang ◽  
Yin Han Gao ◽  
Hui Ke ◽  
...  
Keyword(s):  
Human Body ◽  
High Speed ◽  
Rapid Development ◽  
Analytical Formula ◽  
Electromagnetic Environment ◽  
Public Attention ◽  
High Speed Railway ◽  
Simulation Research ◽  
The Impact ◽  
Ground Potential

With the rapid development of high-speed railway, the problem caused by railway has become the focus of public attention. Whether the railway will damage the electromagnetic environment become an unavoidable topic. Choosing the AC 25KV high-speed railway to study, the impact of its resistive coupling on the human body or different devices is explored. Using the existing analytical formula, the ground potential rise caused by the resistive coupling has been simulated, which intuitively show the different ground potential rise in different situations. Finally, the impact of resistive coupling has been analyzed.

Highway Passenger Transport Development Strategy with the Competition of High-Speed Railway

2011 ◽  
Vol 94-96 ◽  
pp. 527-530
Author(s):  
Si Tao Hu ◽  
Xue Mei Wang
Keyword(s):  
Development Strategy ◽  
High Speed ◽  
Choice Behavior ◽  
Rapid Development ◽  
Technical Support ◽  
Passenger Transport ◽  
High Speed Railway ◽  
Travel Choice ◽  
Support Resource ◽  
The Impact

With the rapid development of high-speed passenger railway and inter-city railway, highway passenger transport is facing an unprecedented competition and pressure. The impact of high-speed railway on highway passenger transport has been analysis and the transport characteristics of high-speed railway are compared with the highways’. On the basis of the travel choice behavior of passengers analysis, the systematized countermeasures of highway passenger transport are put forward including precise orientation, strengthen marketing enhancement, technical support, resource integration, brand service and government help.

A Method and Device for Testing Impact Resistance of Glassware

2015 ◽  
Vol 237 ◽  
pp. 154-159
Author(s):  
Szymon Zacharski ◽  
Wojciech Jóźwik
Keyword(s):  
Impact Strength ◽  
Research Laboratory ◽  
High Speed ◽  
Test Procedure ◽  
Impact Resistance ◽  
Digital Camera ◽  
Industrial Research ◽  
Different Types ◽  
Pharmaceutical Industries ◽  
The Impact

Currently, nearly 1.5 M tons of different types of glassware are produced in Poland, and the majority of it is used as packaging in the food, cosmetic, and pharmaceutical industries. The article presents a method for testing impact resistance of glassware, which was developed at the ITeE-PIB. The authors also present a prototype of a device for glassware tests, discuss a test procedure applied in such tests, and show the results of verification tests for which a high-speed digital camera was used to record the impact strength and the propagation of cracks in glassware. The device in question has been successfully implemented in an industrial research laboratory.

scholarly journals Characteristics of fire in high-speed train carriages

2019 ◽  
Vol 38 (1) ◽  
pp. 75-95
Author(s):  
Haiquan Bi ◽  
Yuanlong Zhou ◽  
Honglin Wang ◽  
Qilin Gou ◽  
Xiaoxia Liu
Keyword(s):  
Numerical Simulation ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Ignition Temperature ◽  
High Speed ◽  
Rapid Development ◽  
Longitudinal Direction ◽  
High Speed Train ◽  
Fire Source

With the rapid development of high-speed railways, safety hazards presented by train fires cannot be ignored. An effective design for protection against fire in high-speed trains is essential to ensure passenger safety. In this study, the cone calorimeter and ignition temperature tester were used to carry out combustion experiments on materials constituting the main components of the train. The heat release rate, smoke yield, CO yield, and ignition temperature of combustible materials were tested. Based on the experimental data of material combustion, a numerical model of the high-speed train carriage fire was simulated. The accuracy of the numerical simulation was verified by drawing a comparison with the full-scale train fire experiment in existing literature. The numerical simulation results revealed that when the fire source is present at the corner of the carriage end door, the fire develops to the maximum possible extent in approximately 25 min, with a peak heat release rate of approximately 38.4 MW. Increase in the carriage fire heat release rate and breakage of windows occur almost simultaneously. Improvement of the fireproof performance of windows can inhibit and delay the carriage fire development. For the flashover of carriage fire, the spread speed of the flashover area in the longitudinal direction inside the carriage is approximately 1.9 m/s. The end door area furthest from the fire source in the carriage has strong flashover, while the flashover in other areas is weak.

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