Thermal Environmental Factors Research Articles

A pilot study on thermal comfort in Indian Railway pantry car chefs

An Indian railway pantry car kitchen is a typical kitchen, where involves various kinds of thermal environment factors. Till now, the research related to pantry car kitchen is rarely reported. Therefore, this pilot study explores the thermal environmental factors and its impact on the chef’s comfort in two different pantry car kitchen (Non-AC and AC) using a subjective and physical measurement technique. The thermal comfort level was quantified by Predicted Mean Vote (PMV) Index and Predicted Percentage Dissatisfied (PPD) Index. The thermal sensation of non-air-conditioned pantry cars was hot with PMV and PPD values are 2.93 and 99% respectively. Whereas, air-conditioned pantry cars was a warm thermal sensation with PMV and PPD values are 2.17 and 84% respectively. Moreover, most of the chef (86%) are perceived thermal discomfort in both pantry car kitchens. The result concluded that both types of pantry car kitchens are having thermal sensation effect of hot and warm. A further detail study is necessary and a possible design intervention may require to enhance thermal comfort of chefs.

Study on Control of Thermal Environmental Factors for Improvement of Productivity of Laying Hens in Summer

Study on Control of Thermal Environmental Factors for Improvement of Productivity of Laying Hens in Summer

Factors Affecting Broiler Production: A Meta-Analysis

ABSTRACT The meta-analysis data were obtained from a survey of published articles over 15 years. The data were selected to classify the factors that impact broiler production and separated by influence aspects of animal production (thermal environment and other factors). The relevant data for each study were systematized, grouped and later tabulated and inserted into a database prepared in a spreadsheet. The variables used to analyze the thermal environment were temperature (comfort, high and low) and performance data (weight gain, feed intake, and feed conversion). The variables used for other features were ventilation (TER = tunnel + evaporative cooling, PP = positive pressure, NV = natural ventilation) and performance (feed conversion, live weight, mortality, and weight gain). The factors that may influence the production of broilers were tested by covariance analysis, Pearson correlation coefficient and divergence analysis, about the Cobb®, Ross® and Hubbard® strains. The results showed that the factors that most influenced the performance of broilers were temperature, ventilation rate, and genetic strain.

Scrotal infrared digital thermography predicts effects of thermal stress on buffalo (Bubalus bubalis) semen

The objective was to use scrotal infrared digital thermography to evaluate effects of thermal stress on semen quality of Murrah buffalo (Bubalus bubalis) breeding bulls. Ejaculates from 109 Murrah bulls maintained at three semen stations were evaluated for: ejaculate volume, sperm concentration (SCON), initial motility (IM), percent live sperm (LIVE), acrosome integrity of fresh semen (AIFS), plasma membrane integrity of fresh semen (PMIFS), head abnormalities of fresh semen (HAFS), midpiece abnormalities of fresh semen (MPAFS), tail abnormalities of fresh semen (TAFS), post-thaw motility (PTM), acrosome integrity of post-thawed semen (AIPT) and plasma membrane integrity of post-thawed semen (PMIPT). Scrotal and ocular surface temperatures were acquired during rainy, winter and summer seasons, using an FLIR i5 infrared camera. Thermographic images were analyzed with Quick Report 1.2 SP2 software and temperature data acquired. Daily mean temperature and mean relative humidity were used to determine the temperature-humidity index (THI). Environmental factors were analyzed using CORR to determine collinearity among independent variables. There was a high correlation among THI, proximal, mid and distal scrotal temperatures (r ≥ 0.73). Therefore, distal pole temperature (DPT), THI, temperature gradient (TG) and ocular temperature (OcT) were used in the analysis of variance (ANOVA) and in regression analysis of dependent variables. The THI, DPT, TG and OcT had significant influences on sperm abnormalities, acrosome and plasma membrane integrity of fresh as well as post-thawed semen. The TG had significant effects on LIVE and SCON. All semen quality parameters were predicted (regression analysis) as a function of the three independent factors. We concluded that scrotal infrared thermography was useful for assessing influences of thermal stress and environmental factors on characteristics of buffalo semen.

The contributions of rate and duration of stem radial increment to annual increments of Picea meyeri in a sub-alpine habitat, North-Central China

The increment duration and rate were equally important in controlling annual stem radial increments of Picea meyeri at its upper limit of distribution. Stem radial increment rate and duration are the most important parameters in determining the width of annual tree rings. To identify the contributions of rate and duration to annual radial increments and their relationships with environmental factors, we analyzed intra-annual stem increments of five Picea meyeri trees in a sub-alpine habitat of North-Central China over 7 years (2008–2015, except for the year 2012) with point dendrometers in this study. The results showed the following. (1) We estimated that approximately 53% of the variability in the annual radial increments is attributable to the rate of radial increment and approximately 47% to its duration. (2) The contribution of cessation time to the annual increments was more than three times that of the initiation time. (3) The initiation of radial increment was primarily controlled by soil temperature and warmer soil temperature could advance the initiation time. The cessation and rate of radial increment were mainly influenced by thermal and light-related environmental factors. During growing seasons, low temperatures and insufficient light caused by many rainy and cloudy days at the high altitudes of the Luya Mountains may result in earlier cessations and lower rates of radial increment. Overall, our results may have further applications in modeling the responses of tree stem growth to climate change in a sub-alpine habitat of North-Central China.

FATORES QUE AFETAM A PRODUÇÃO DE FRANGOS DE CORTE

Brazil occupies a privileged position worldwide in poultry farming. The economic activity is recognized as necessary for the country's GDP and also has a significant climatic diversity. Because of this, different types of aviaries were and still are built in the national territory. The objective of this study was to present a systematic review of the factors that have an impact on the intensive production of broiler chicken based on the scientific publications since the year 2000. The literature review showed a constant evolution and the knowledge about the form of housing that best expresses the genetics of birds. It was found that the thermal environment, air quality and other factors related to the housing of broiler chickens significantly imply in their performance.

Thermal environment analysis and energy conservation research of rural residence in cold regions of China based on BIM platform

In order to study the issue of rural residential energy consumption in cold regions of China, modeled an architecture prototype based on BIM platform according to the affecting factors of rural residential thermal environment, and imported the virtual model which contains building information into energy analysis tools and chose the appropriate building orientation. By analyzing the energy consumption of the residential buildings with different enclosure structure forms, we designed the optimal energy-saving residence form. There is a certain application value of this method for researching the energy consumption and energy-saving design for the rural residence in cold regions of China.

Elastomeric Concrete Plug Joints: A New Durable Bridge Expansion Joint Design

Expansion joints are important components of bridges that accommodate the movements between deck spans that result from thermal loads, traffic loads, and other environmental factors. Experience shows that joints undergo premature deterioration on a regular basis, which leads to unexpected problems caused by leakage of water and other corrosive chemicals over the components of the superstructure and substructure, which in turn leads to premature deterioration of those components. The Virginia Department of Transportation (DOT) has spent millions of dollars over more than 50 years for repair and replacement of joints. Several types of closed joints have been developed and installed in the past three decades to combat this problem. Jointless details at piers and abutments have also been developed and installed in the past three decades to eliminate the need for joints and the associated deterioration. However, the issue persists. The Virginia DOT’s Structure and Bridge Division has developed a new design for a flexible joint system with bonded and debonded zones. An elastomeric concrete material acts as the load-bearing surface as well as the component that allows free expansion and contraction. This joint system has been installed in selected pilot bridges on secondary roads for observation. The performance of this joint system and the challenges faced in its development are discussed.

Thermal comfort in urban green spaces: a survey on a Dutch university campus

To better understand the influence of urban green infrastructure (UGI) on outdoor human thermal comfort, a survey and physical measurements were performed at the campus of the University of Groningen, The Netherlands, in spring and summer 2015. Three hundred eighty-nine respondents were interviewed in five different green spaces. We aimed to analyze people’s thermal comfort perception and preference in outdoor urban green spaces, and to specify the combined effects between the thermal environmental and personal factors. The results imply that non-physical environmental and subjective factors (e.g., natural view, quiet environment, and emotional background) were more important in perceiving comfort than the actual thermal conditions. By applying a linear regression and probit analysis, the comfort temperature was found to be 22.2 °C and the preferred temperature was at a surprisingly high 35.7 °C. This can be explained by the observation that most respondents, who live in temperate regions, have a natural tendency to describe their preferred state as “warmer” even when feeling “warm” already. Using the Kruskal-Wallis H test, the four significant factors influencing thermal comfort were people’s exposure time in green spaces, previous thermal environment and activity, and their thermal history. However, the effect of thermal history needs further investigation due to the unequal sample sizes of respondents from different climate regions. By providing evidence for the role of the objective and subjective factors on human thermal comfort, the relationship between UGI, microclimate, and thermal comfort can assist urban planning to make better use of green spaces for microclimate regulation.

(Invited) Impacts of Environmental Stress Factors on Li-Ion Battery Safety Margins

Since the mid-1990’s, many commercial, automotive, and aerospace platforms have transitioned from heritage aqueous electrolyte nickel-based energy storage batteries to lithium-ion battery (LIB) based electrical power subsystems. For space applications, the transition from nickel-hydrogen (Ni-H2) batteries to LIB’s was accelerated by growing concerns with Ni-H2 raw materials obsolescence issues. Although significant research efforts were undertaken to mitigate the risk of Ni-H2 raw materials obsolescence, the recurring cost of maintaining multiple Ni-H2 battery technology supply sources was prohibitive versus the longer-term benefits of supporting a deliberate transition to LIB technologies. Other transitional market forces such as consumer demands to reduce system mass, volume and cost continue to drive the commercial electronics and automotive industries. While it is widely recognized that the mass market for LIB’s in consumer electronics is reaching maturity, the automotive and aerospace marketplace continues to experience new technology growth opportunities. These emerging markets are highly leveraged against economic incentives to pursue safe and reliable LIB design solutions to meet demanding customer requirements. Traditionally, implementing safe and reliable LIB design solutions into aerospace platforms included considerations of simplistic first-order interactions between thermal, mechanical, and electrical environmental stress factors. However, industry experience indicates that the effect of certain synergistic stress factors on LIB performance characteristics in their service environments is a complex multi-dimensional problem. For example, induced and natural environmental stress factors such as thermal cycling, vibration, and radiation have been shown to impact LIB battery performance and in some cases, safety margins. Specifically, certain high-performance LIB aerospace and automotive power systems have recently been challenged to understand the principles governing lithium-ion cell thermal runaway in far greater detail than previously accepted. The severity of lithium-ion cell thermal runaway has created a need for identifying LIB design modifications which reduce degree of severity. The consequences of thermal runaway have the potential to make lithium-ion chemistry an at-risk technology for some applications. To mitigate these risks, investigators from academia, government, and industry have shifted research efforts toward identifying key factors which contribute to the severity of thermal runaway. This work focuses on identifying gaps and opportunities in achieving new paradigms for mitigating LIB safety hazards. Challenges with current technologies to increase LIB safety margins and steps required to reach the readiness level required for successful insertion in an industrial application will also be presented.

Evaluating equations estimating change in swine feed intake during heat and cold stress.

The objectives of this study were to evaluate heat stress feed intake models for growing swine using a data set assembled from the literature and to develop a series of new equations modeling the influence of the thermal environment and interactions between the thermal environmental and other factors on feed intake. A literature survey was conducted to identify studies assessing intake responses to temperature. The resulting data set comprised 35 studies containing 120 comparisons to thermoneutral intake. Intake as a fraction of thermoneutral intake (FFI) was the primary response variable, where a value of 1 represented no change from thermoneutral intake. The FFI predicted by NRC and a recent model from a meta-analysis (Renaudeau et al.,) were compared to observed values. New parameters for the NRC equation (NRCmod) were derived, and a series of new equations incorporating duration of exposure (TD), temperature cycling (TC), and floor type (TH) were also derived. Root-mean-square prediction error (RMSPE) and concordance correlation coefficients were used to evaluate all models. The RMSPE for the NRC model was 23.6 with mean and slope bias accounting for 12.6% and 51.1% of prediction error, respectively. The TD, TC, and TH models had reduced RMSPE compared with NRC: 12.9 for TD, 12.6 for TC, and 12.9 for TS. Substantial improvements were also made by refitting parameters (NRCmod; RMSPE 13.0%). In NRCmod, TD, TC, and TH, random error was the predominant source, accounting for over 97% of prediction error. The Renaudeau et al. model was also evaluated. Renaudeau et al. had relatively low RMSPE (22.3) for intake but higher RMSPE for FFI (22.6) than NRC, NRCmod, TD, TC, or TH. Additional parameters were derived for the Renaudeau et al. equation to account for housing system and diet characteristics. This adjustment reduced RMSPE of predicting feed intake (16.0) and FFI (16.3) and reduced systematic bias in the equation. This evaluation of equations highlights the effects of novel explanatory variables on feed intake during heat stress, and the comparison can be useful when selecting a model that best explains variability in feed intake responses to heat stress given available input data.

Thermal Acceptability Based on Complaints in Offices in Summer

This paper focuses on the relationship between thermal environment and thermal acceptability based on complaints. Thermal environment factors and occupants complaints were measured by "thermal complaints voting device" fabricated for this study on each work station in eight offices in summer. The key results are that each hot complaints and cold complaints occurred in a wide range of temperature than we expected and there was an overlap between temperature of hot and cold complaints. As a temperature range occupants experienced in their office was broader, there was more distinction of average and midium between cold and hot complaints. Also, when occupants less complained, they had higher thermal satisfaction and self-assessed productivity.

Dynamic modeling and motion precision analysis of spacecraft manipulator with harmonic drive considering the alternate thermal field in orbit

Nowadays, the harmonic drive is widely used as the reducer in the spacecraft manipulator, which may influence the dynamical properties of flexible spacecraft manipulator. The alternative thermal environment makes the spacecraft manipulator to experience periodic heating and cooling in the sunlight and shadow region of the Earth. The analysis of dynamic modeling and motion precision of flexible spacecraft manipulator with harmonic drive, considering the alternate thermal field in orbit is of significant importance for spacecraft manipulator designers in the early stage of design. The thermal load influences the motion precision, which reflects whether the mechanism is performed normally or not. In order to evaluate the loss of motion precision, this paper establishes the dynamical model of spacecraft manipulator with harmonic drive considering the alternate thermal field in orbit. A thermal analysis model of flexible spacecraft manipulator with harmonic drive is developed to characterize the thermal response of the whole spacecraft manipulator system subjected to space heat flux. Two different altitudes including low Earth orbit and geosynchronous Earth orbit are considered. Moreover, the transient temperature fields in different orbits of spacecraft manipulator and the effects of the thermal environment factors on the spacecraft manipulator are investigated. Simulation results reveal the evolution process of the transient temperature field of the spacecraft manipulator system. According to the results, the maximum temperature difference for space manipulator can lead to more severe precision loss compared with the minimum temperature difference. In addition, the vibration frequency of angular velocity error is determined by the maximum thermal heat flux. The proposed method is useful for forecasting the temperature distribution of the spacecraft manipulator system, and will provide meaningful information for performance enhancement of the aerospace facilities.

도시근린공원의 열환경 개선을 위한 열쾌적성 평가

본 연구는 도시 근린공원의 열쾌적성을 평가하고 이에 따른 열환경 개선방안을 도출하고자 연구를 진행하였다. 먼저 공원의 주요 열환경 인자의 분포특성 및 공간 유형별 차이를 평가한 결과, 기온, 상대습도, 풍속의 경우 공간적으로 뚜렷한 차이를 보이지 않았다. 그러나 평균복사온도는 공간의 개방정도 및 포장재질에 따라 큰 차이를 나타내는 것으로 확인되었다. 추출된 열환경 인자를 토대로 공간 유형에 따른 열쾌적성을 평가한 결과, 광장의 PMV(Predicted Mean Vote, 예상온열감) 지수가 4.39로 가장 높게 나타났으며, 동선의 경우 2.58, 녹지 1.90 그리고 휴게공간은 0.42로 평가되었다. 이러한 열쾌적성을 결정하는 열환경 요인에 대한 중요도를 평가해보기 위하여 PMV 회귀모형을 구축한 결과, 평균복사온도(1.084), 풍속(-0.280), 기온(0.013), 상대습도(-0.009)의 순으로 PMV에 대한 상대적인 중요도가 높게 나타났다. 열환경적 측면에서 개선이 필요한 지역을 대상으로 시나리오 분석을 실시한 결과, 반사율, 색상, 포장재질의 물리적 특성 변화를 통해 인체가 체감하는 열쾌적성을 향상시킬 수 있으며, 실제 공원에 이를 적용하여 개선안을 마련할 수 있을 것으로 판단된다. This study was conducted to analyze the thermal comfort in the urban neighborhood park and to obtain a plan for improvement of the thermal environment. First, in the result of the analysis of the distribution characteristics of the park's main thermal environment factors and differences among types of space, temperature, relative humidity, and wind speed did not show a clear difference spatially. However, the median radiant temperature showed great differences according to the openness of the space and the covering material. According to the evaluation of thermal comfort by types of space based on derived thermal environmental factors, the PMV value of the square was the highest at 4.39, the paths showed 2.58, greenery 1.90, and resting spaces 0.42. In the result of the PMV regression model established for the evaluation of the significance of these thermal environment factors that decide thermal comfort, it showed that the relative significance to the PMV was as follows in decreasing order: median radiant temperature(1.084), wind speed(-0.280), temperature(0.013), and relative humidity(-0.009). When conducting a scenario analysis on the areas with need for improvement in thermal environment, it was found that through reflectivity, color and the change in the physical properties of packing materials the thermal comfort felt by the body could be improved, and it is believed that through this the improvement plan can be established.

Assessment of Indoor Environmental Quality in Open-Plan Offices

This study aims to analyze the factors of indoor environment on occupants’ health and comfort by post-occupancy evaluation (POE) and to accumulate the fundamental data of occupants’ behaviour in relation to indoor environment, in an effort to ascertain the optimal building energy management system (BEMS). For this purpose, indoor temperature, relative humidity, vertical temperature distribution, air velocity, predicted mean vote (PMV), radiant temperature, outdoor temperature, and humidity were measured for evaluating thermal environment for nearly 2 years. Indoor air contaminants, such as PM10, CO2, formaldehyde, and volatile organic compounds (VOCs) were measured in the building and at outdoor locations. Working plane illuminance, window luminance, and the equivalent continuous a-weighted sound pressure level (Leq) were also monitored. In addition, the occupants in the intelligent office building were surveyed regarding the indoor environmental quality via the intranet. Results showed that all indoor environmental factors satisfied the recommendation, except the indoor relative humidity and PMV. The physical factors of thermal environment had been stable since two months after it was built. However, it should be necessary to improve the sound privacy caused by low background noise, seasonal air-conditioning for appropriate humidity, air freshness, and Video Display Terminal (VDT) glare in order to reduce the level of occupants’ annoyance.

Thermal analysis of composite solar array subjected to space heat flux

Thermal analysis of the solar array is of great importance for the safe operation of spacecraft. In this paper, a thermal analysis model of composite solar array with complex structure is developed to characterize the thermal response of the whole solar array system subjected to space heat flux. Two different altitudes including low Earth orbit and geosynchronous orbit are discussed. The external heat flux of orbiting solar array in these orbits is proposed according to the flight attitudes. The thermal analysis model for the complex solar array is developed, in which all the honeycomb panel, simplified hinges, composite frames and yokes are taken into account. Moreover, the transient temperature fields in different orbits of all the components and the effects of the thermal environment factors on different components are discussed, and the thermal response of the solar array with two commonly used materials are contrastive analyzed. Simulation results reveal the evolution process of the transient temperature field of the whole solar array system. The proposed method is useful for forecasting the temperature distribution of the whole solar array system, and has important significance for the aerospace engineering.

Indoor Thermal Environment and Energy Conservation of Seaside Resident Building in Xiamen in Summer

The good and comfortable environment is beneficial to the health, and can improve working efficiency, make people imbued with more creativity. This means strengthening the competitiveness, increase economic efficiency. So, creating the good building environment not merely has a meaning on technology, and has social effect and economic meaning. In order to understand the situation of indoor thermal environment of the seaside residential building generally, a field measurement on the condition of summer was made in Xiamen from the last ten days of July to the first ten day of Aug, 2005, 2006 and 2008. Test the thermal environment and investigate the thermal comfort in residential buildings of natural ventilation condition, analyze the main influence factors of indoor thermal environment, and evaluate indoor thermal comfort with effective temperature (ET). The curves of indoor air temperature and relative humidity reflect the character of high temperature and high relative humidity in summer in Xiamen residential buildings. Discuss the methods of building energy saving. Suggest that, for seaside city in hot days, the natural ventilation and interval natural ventilation should be the main fundamental methods of improving the resident building thermal environment.

Indoor Thermal Environment Simulation of Xi'an Residential Building in Summer

Natural ventilation is an important role to improve the residential building indoor thermal environment in summer. This paper use Energy Plus to simulate indoor thermal environment and use CFD to simulate indoor air flow for Xi’an residential building, analysis the influence that different ventilation mode for indoor thermal environment factors. Then with the simulated result of PMV-PPD value to estimate indoor thermal comfort. Proved night ventilation is necessary in residential building in Xi’an and effectiveness to improve indoor thermal comfort.

Delaware's Indian River Inlet Bridge

Plagued by a serious scour problem, the existing bridge over the Indian River Inlet in Sussex County, Delaware, will be replaced by a 1,750-ft cable-stayed bridge. The new bridge is being constructed under a design–build contract by the team of Skanska and AECOM. The bridge is due to open in summer 2011. As part of this project, a comprehensive structural monitoring system has been designed and will be installed on the bridge to aid in the long-term maintenance and operation of this significant structure. The concept and the design of the monitoring system were proposed by the Center for Innovative Bridge Engineering, University of Delaware. The system has been designed with the intent of providing quantitative data on the long-term performance of the bridge, which can be used to augment the traditional inspection program. The all-fiber-optic system will include 119 embedded and surface-mounted sensors that will measure strain in the deck and pylons; accelerations on the deck, pylons, and cables; deck inclination; chloride penetration in the deck; temperature; and wind speed and direction. Slow, gradual trends resulting from thermal effects and environmental factors will be captured by the monitor data, readings taken on the hour, every hour. Bridge response under intense live loads, such as heavy vehicles and high winds, will be recorded as event data. A series of baseline readings and diagnostic tests will be conducted once the bridge is completed and will be used for future comparisons. The paper presents an overview of the monitoring system and the monitoring program, a description of the way the data will be used, and the owner's perspective.

Validity and evaluation method of combined thermal environmental factors upon human body

Validity and evaluation method of combined thermal environmental factors upon human body