PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING最新文献_第9页

Analyzing the Effect of Temperature on Squash Ball Impacts Using High-Speed Camera Recordings 用高速摄像机记录分析温度对壁球撞击的影响

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-09-24 DOI: 10.3311/ppme.18381

Bence Ferenc Berencsi, A. Kossa

{"title":"Analyzing the Effect of Temperature on Squash Ball Impacts Using High-Speed Camera Recordings","authors":"Bence Ferenc Berencsi, A. Kossa","doi":"10.3311/ppme.18381","DOIUrl":"https://doi.org/10.3311/ppme.18381","url":null,"abstract":"Description of the impact characteristics of different types of balls has a great importance in sport science and in engineering. The primary objective of the present paper is to investigate the effect of the temperature on the impacts of different types of squash balls from a given company. The shots were performed using a self-built air-cannon. The impacts were recorded by a high-speed camera and the recorded videos were analyzed by an image-processing method based on a background subtraction technique. Summarizing the main dynamical parameters, we can conclude that increasing the initial speed will decrease the contact time, the coefficient of restitution (COR) and the rebound resilience, whereas these parameters increase at elevated temperatures. The compression tests revealed that within the low velocity range the deformation of the ball’s material and not the compression of the inner gas is the main contribution in the force needed to compress the ball. However, when the ball suffers large deformations, the internal air pressure has a huge effect on the rebound behavior. The measurements revealed that there is an optimal initial velocity distinct from the maximum one where the rebound velocity of the ball is higher than in all other cases. From the results we can state that the ball's overall stiffness grows as the temperature increases.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76262869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Analysis of Smart Zone Heating in Different Heating Systems 不同供热系统中智能区域供热的分析

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-09-24 DOI: 10.3311/ppme.17437

Rastislav Ingeli, P. Buday

引用次数: 1

Comparison of Surface Roughness When Turning and Milling 车削和铣削时表面粗糙度的比较

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-09-24 DOI: 10.3311/ppme.17898

Abdul W. Mgherony, Balázs Mikó, Gabriella Farkas

引用次数: 3

Experimental Investigation and Numerical Prediction of the Effects of Cutting Tool Geometry During Turning of AISI 316L Steel AISI 316L钢车削过程中刀具几何形状影响的实验研究与数值预测

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-09-24 DOI: 10.3311/ppme.16844

A. Benmeddour

{"title":"Experimental Investigation and Numerical Prediction of the Effects of Cutting Tool Geometry During Turning of AISI 316L Steel","authors":"A. Benmeddour","doi":"10.3311/ppme.16844","DOIUrl":"https://doi.org/10.3311/ppme.16844","url":null,"abstract":"In this work, a numerical and an experimental study aimed to gain a better understanding of the impact of tool geometry such as (rake angle and cutting edge radius) on the temperature distribution and residual stresses in machining surface of AISI 316L stainless steel have been presented. To evaluate the experimental results, various experimental equipment was used, such as a conventional lathe to carry out the machining operations, the cutting force was measured using a Kistler dynamometer and X-ray diffraction technique was employed for determination of the residual stresses distribution on the machined surfaces. In addition, A thermo-mechanically coupled finite element (FE) analysis for cutting process is developed through ABAQUS code to predict the temperature distribution and residual stresses using an Arbitrary Lagrangian-Eulerian (ALE) approach. An inverse identification method has been used to determine the adequate Johnson-Cook (JC) material model parameters to obtain a good correlation between the cutting force measurements and numerical one. The FE model was then validated by comparison of the numerical results of residual stresses with experimental measurements for different tool geometries, which revealed a reasonable agreement.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84133153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Chromatic Discrimination Thresholds as a Function of Color Differences and Cone Excitations 色差和视锥刺激的色差判别阈值

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-09-21 DOI: 10.3311/ppme.18691

Á. Urbin, B. Nagy

{"title":"Chromatic Discrimination Thresholds as a Function of Color Differences and Cone Excitations","authors":"Á. Urbin, B. Nagy","doi":"10.3311/ppme.18691","DOIUrl":"https://doi.org/10.3311/ppme.18691","url":null,"abstract":"In this paper, Just Noticeable Differences (JNDs) of color-normal subjects measured towards the Protan, Deutan, and Tritan confusion points are presented as a function of the chromaticity of the reference points. Measurements were executed with the Cambridge Colour Test Trivector test in equidistant reference points towards eight directions equally spaced and centered on the neutral reference point in the CIE 1976 UCS diagram.Results were evaluated as the function of the distance between the reference points and the neutral point. The reference points were the chromaticities of the backgrounds of the pseudoisochromatic plates in the test, and the neutral point was defined as equal energy white. The evaluation was performed considering ∆Eu'v' differences and L/(L + M) and S/(L + M) ratios of the cone-excitations.Chromatic discrimination thresholds exceeded the normative upper limit of color normal subjects in ∆Eu'v' units at extreme reference points. Shifting the reference points from the neutral point towards the confusion points indicated an increase of Just Noticeable Differences measured towards the confusion points following second-order polynomials. Based on our results a model estimating the JNDs expressed in ∆Eu'v' units towards the confusion points was recommended.Even though CIE 1976 UCS diagram is not a perceptually uniform color space, the Just Noticeable Differences measured with the CCT correlate with the corresponding L' and S' cone excitations. This confirms the basic applicability of the CIE 1976 UCS diagram for characterizing Just Noticeable Differences. For complete perceptual analysis, the use of cone-excitation-based metrics is still essential and recommended.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85180939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Prandtl Number Effects on the Entropy Generation During the Transient Mixed Convection in a Square Cavity Heated from Below 普朗特数对从下加热的方形腔内瞬态混合对流熵生成的影响

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-08-30 DOI: 10.3311/PPME.17563

Nawal Ferroudj, H. Koten, Sacia Kachi, S. Boudebous

{"title":"Prandtl Number Effects on the Entropy Generation During the Transient Mixed Convection in a Square Cavity Heated from Below","authors":"Nawal Ferroudj, H. Koten, Sacia Kachi, S. Boudebous","doi":"10.3311/PPME.17563","DOIUrl":"https://doi.org/10.3311/PPME.17563","url":null,"abstract":"This numerical study considers the mixed convection, heat transfer and the entropy generation within a square cavity partially heated from below with moving cooled vertical sidewalls. All the other horizontal sides of the cavity are assumed adiabatic. The governing equations, in stream function–vorticity form, are discretized and solved using the finite difference method. Numerical simulations are carried out, by varying the Richardson number, to show the impact of the Prandtl number on the thermal, flow fields, and more particularly on the entropy generation. Three working fluid, generally used in practice, namely mercury (Pr = 0.0251), air (Pr = 0.7296) and water (Pr = 6.263) are investigated and compared. Predicted streamlines, isotherms, entropy generation, as well as average Nusselt numbers are presented. The obtained results reveal that the impact of the Prandtl number is relatively significant both on the heat transfer performance and on the entropy generation. The average Nusselt number increase with increasing Prandtl number. Its value varies thereabouts from 3.7 to 3.8 for mercury, from 5.5 to 13 for air and, from 12.5 to 15 for water. In addition, it is found that the total average entropy generation is significantly higher in the case of mercury (Pr«1) and water (Pr»1) than in the case of air (Pr~1). Its value varies approximately from 700 to 1100 W/m3 K for mercury, from 200 to 500 W/m3 K for water and, from 0.03 to 5 W/m3 K for air.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80927855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Ensuring the Required Potable Water Temperature in Water Pipeline Inside Buildings 确保建筑物内供水管道中饮用水所需温度

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-08-09 DOI: 10.3311/PPME.18205

Dominika Macková, J. Peráčková

引用次数: 1

Energy Balance of a Low Energy House with Building Structures with Active Heat Transfer Control 采用主动传热控制的低能耗建筑结构的能量平衡

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-07-14 DOI: 10.3311/PPME.17462

D. Kalús, Z. Straková, Matej Kubica

{"title":"Energy Balance of a Low Energy House with Building Structures with Active Heat Transfer Control","authors":"D. Kalús, Z. Straková, Matej Kubica","doi":"10.3311/PPME.17462","DOIUrl":"https://doi.org/10.3311/PPME.17462","url":null,"abstract":"A qualitatively new dimension has been introduced to the issue of building structures for energy-efficient buildings by the system of Active Thermal Insulation (ATI), which is already applied in the construction of such buildings. ATI are embedded pipe systems in the envelope structures of buildings, into which we supply a heat-carrying medium with adjusted temperature, so this constitutes a combined building-energy system. This introduces the concept of an internal energy source understood as an energy system integrated into the zone between the static part and the thermal insulation part of the building structure envelope. Under certain conditions, the ATI can serve as a heat recuperator or as an energy collector for a heat pump application. ATI consists of pipe systems embedded in building structures, in which the medium circulates heated by energy from any heat source. The function of the system is to reduce or eliminate heat losses through non-transparent structures in the winter and at the same time to reduce or eliminate heat gains in the summer. It is especially recommended to apply heat sources using renewable energy sources due to the required low temperatures of the heating medium and thus shorten the heating period in the building. Also recommended is to apply ATI for the use of waste heat. Buildings with a given system show low energy consumption and therefore meet the requirements of Directive no. 2018/844/EU, according to which, from 01.01.2021, all new buildings for housing and civic amenities should have energy needs close to zero.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75325341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Composite Shaftless Roller Design for Conveyor System 输送系统复合无轴托辊设计

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-07-09 DOI: 10.3311/PPME.17554

G. Wheatley, Mohammad Zaeimi

引用次数: 1

Optimization of Dimensional Tolerances and Material Removal Rate in the Orthogonal Turning of AISI 4340 Steel AISI 4340钢正交车削尺寸公差及材料去除率优化

IF 1.3

PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING Pub Date : 2021-07-06 DOI: 10.3311/PPME.16563

C. Sumesh, Dawood Sheriff Akbar, Hari Shankar Purandharadass, Raghunandan J. Chandrasekaran

引用次数: 0