scholarly journals Entropy Generation Analysis of Human Thermal Stress Responses

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Satish C. Boregowda ◽  
Robert E. Choate ◽  
Rodney Handy
Keyword(s):  
Thermal Stress ◽  
Relative Humidity ◽  
Air Temperature ◽  
Entropy Generation ◽  
Stress Responses ◽  
Military Medicine ◽  
Thermal Response ◽  
Response Data ◽  
Physiological Reaction ◽  
Human Thermal Model

The present study involves application of an open system entropy generation formulation to analyze human thermal stress responses. The time-series human thermal stress response data are obtained by conducting a simulation using a validated finite-element human thermal model (FEHTM). These simulated human thermal response data are used as an input to the entropy generation expression to obtain human entropy generation (HEG) values. The effects of variables such as air temperature, relative humidity, physical activity, and clothing on entropy generation are examined. A design of experiment (DOE) approach is utilized to study the interaction effects of air temperature and relative humidity on entropy generation. The study establishes the importance and utility of entropy generation as a holistic measure of human thermal physiological reaction to external and internal changes. This novel study has great potential for use in military medicine, rehabilitation, sports, and related applications.

scholarly journals Perubahan Temperature Humidity Index (THI) di Pulau Jawa sejak 1981 hingga 2019

2021 ◽  
Vol 35 (2) ◽  
Author(s):  
Qurrata A'yun Kartika ◽  
Rahmat Hidayat ◽  
Rista Hernandi Virgianto
Keyword(s):  
Thermal Stress ◽  
Relative Humidity ◽  
Air Temperature ◽  
Pearson Correlation ◽  
Surface Air Temperature ◽  
North Coast ◽  
Anthropogenic Activity ◽  
Temperature Humidity Index ◽  
The North ◽  
Humidity Index

Abstrak Pulau Jawa mengalami peningkatan jumlah penduduk dari waktu ke waktu. Peningkatan ini berdampak pada tingginya aktivitas antropogenik yang menghasilkan emisi yang diantaranya dapat menyebabkan perubahan suhu udara. Suhu udara sangat berkaitan dengan thermal stress yang mempengaruhi kenyamanan bahkan kesehatan manusia. Thermal stress dapat diukur dengan Temperature Humidity Index (THI) dengan suhu udara rata-rata permukaan dan Relative Humidity (RH) sebagai variabel bebas. Penelitian ini menganalisis sejauh mana perubahan suhu udara permukaan, RH dan THI terhadap waktu. Kemudian daerah dengan perubahan THI yang paling besar akan dianalisis keterkaitannya jumlah penduduk menggunakan korelasi Pearson. Berdasarkan hasil penelitian diketahui terjadi perubahan suhu udara udara permukaan sebesar -0.27 hingga 1.17⁰C diikuti perubahan RH sebesar -2.21% hingga 0.77% dan terjadi perubahan THI hingga 0,72⁰C sejak 1981 hingga 2019 terutama di pesisir utara bagian barat Pulau Jawa. Selain itu, THI di sekitar DKI Jakarta juga memiliki nilai korelasi simultan yang tinggi dengan jumlah penduduk sebesar 0,81, korelasi lag 1 tahun sebesar 0,69, sementara korelasi lag 2 tahun sebesar 0,67. Temuan ini mengindikasikan peningkatan jumlah penduduk berdampak terhadap peningkatan THI pada DKI Jakarta. Abstract Java has experienced an increase in population from time to time. This increase has an impact on high anthropogenic activity which results in emissions, which can cause changes in air temperature. Air temperature is closely related to thermal stress which affects comfort and even human health. Thermal stress can be measured by the Temperature Humidity Index (THI) with the average surface air temperature and Relative Humidity (RH) as the independent variable. This study analyzes the extent of changes in surface air temperature, RH and THI with time. Then the areas with the greatest THI changes will be analyzed for their correlation using the Pearson correlation. Based on the research results, it is found that there has been a change in surface air temperature of -0.27 to 1.17⁰C followed by changes in RH from -2.21% to 0.77% and there has been a change in THI to 0.72⁰C from 1981 to 2019, especially on the north coast of the western part of Java. In addition, THI around DKI Jakarta also has a high simultaneous correlation value with a population of 0.81, a 1-year lag correlation of 0.69, while a 2-year lag correlation of 0.67. These findings indicate an increase in population has an impact on increasing THI in DKI Jakarta. 

scholarly journals ANÁLISE BIOCLIMÁTICA E INVESTIGAÇÃO DO CONFORTO TÉRMICO EM AMBIENTE EXTERNO NA REGIÃO CENTRAL DO RS

2019 ◽  
Vol 34 (3) ◽  
pp. 377-388
Author(s):  
Zanandra Boff Oliveira ◽  
Alberto Eduardo Knies
Keyword(s):  
Heat Stress ◽  
Thermal Stress ◽  
Relative Humidity ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Central Region ◽  
External Environment ◽  
Dew Point ◽  
Santa Maria ◽  
E Mail

ANÁLISE BIOCLIMÁTICA E INVESTIGAÇÃO DO CONFORTO TÉRMICO EM AMBIENTE EXTERNO NA REGIÃO CENTRAL DO RS   ZANANDRA BOFF DE OLIVEIRA1, ALBERTO EDUARDO KNIES2   Professora adjunta, Coordenadoria Acadêmica, Universidade Federal de Santa Maria Campus em Cachoeira do Sul, Rua Ernesto Barros, nº 1345, Bairro Santo Antônio, cep: 96506-322, Cachoeira do Sul – RS, Brasil. E-mail: [email protected] Professor adjunto, Universidade Estadual do Rio Grande do Sul Unidade em Cachoeira do Sul, Rua Sete de Setembro, nº 1040, Bairro Santo Centro, cep: 96508-010, Cachoeira do Sul – RS, Brasil. E-mail: [email protected]   RESUMO: o presente trabalho teve como objetivo realizar a análise bioclimática e a investigação do conforto térmico em ambiente externo na região central do RS. Para isso, utilizaram-se os seguintes índices de conforto térmico: índice de temperatura e umidade (ITU) e índice de desconforto humano (IDH). Os dados meteorológicos de temperatura do ar máxima (Tmax) e mínima (Tmin) e umidade relativa do ar máxima (URmax) e mínima (URmin) foram obtidos de uma série de 10 anos (2005-2015) de dados de uma estação meteorológica automática instalada em Santa Maria (RS). A temperatura do ponto de orvalho foi estimada a partir da Tmax e Tmin e da URmin e URmax, respectivamente. Os índices de conforto térmico foram calculados a partir das médias diárias do período (10 anos) para a situação de máximo desconforto térmico que ocorre nos extremos: 1) quando a temperatura do ar é máxima e a umidade relativa do ar é mínima - denominados de ITUmax e IDHmax; 2) quando a temperatura do ar é mínima e a umidade relativa do ar é máxima - denominados de ITUmin e IDHmin. Em função da elevada amplitude térmica mensal (>10ºC<18ºC) e diária (>5ºC<10ºC), os valores dos índices de conforto térmico (ITU e IDH) variam entre 51,5 e 80,4, indicando que a situação de conforto térmico do ambiente externo na região central do RS vai nos extremos de estresse térmico devido ao frio (julho) a estresse térmico devido ao calor (janeiro). No período de maio a outubro o conforto térmico ocorre na Tmax, mas na Tmin a situação é de desconforto a estresse por frio. No período de novembro a fevereiro, o conforto térmico ocorre na Tmin, mas na Tmax ocorre desconforto a estresse térmico por calor. Nos meses de março e abril, o desconforto ocorre tanto por frio quanto por calor. Dessa forma, para a produção zootécnica e para o conforto térmico humano na região central do RS, são necessárias práticas de acondicionamento ambiental que visem a minimização do estresse térmico.   Palavra-chaves: índices de conforto térmico; análise bioclimática; amplitude térmica.   BIOCLIMATIC ANALYSIS AND RESEARCH OF THERMAL COMFORT IN EXTERNAL ENVIRONMENT IN THE CENTRAL REGION OF RS   ABSTRACT: The present work had the aim of performing the bioclimatic analysis and the investigation of the thermal comfort in an external environment in the Central region of RS. For this, the following thermal comfort indexes were used: temperature and humidity index (THI) and human discomfort index (HDI). The maximum air temperature (Tmax) and minimum air temperature (Tmin) and maximum relative humidity (URmax) and minimum air humidity (URmin) were obtained from a series of 10 years (2005 to 2015) of data of an automatic meteorological station installed in Santa Maria - RS. The temperature of the dew point was estimated from the Tmax and Tmin and the URmin and URmax, respectively. The thermal comfort indexes were calculated from the daily average of the period (10 years) for the situation of maximum thermal discomfort that occurs in the extremes: (i) when the air temperature is maximum and the relative humidity of the air is minimal - denominated of THImax and HDImax; (ii) when the air temperature is minimal and the relative humidity of the air is maximum - denominated THImin and HDImin. In function to the high temperature amplitude, monthly (> 10ºC <18ºC) and daily (> 5ºC <10ºC), the values of thermal comfort indexes (THI and HDI) vary from 51.5 to 80.4, indicating that thermal comfort of the external environment in the Central region of RS goes in the extremes of thermal stress due to the cold (July) to the heat stress due to the heat (January). In the period from May to October the thermal comfort occurs in Tmax, but in Tmin the situation is of cold stress discomfort. In the period from November to February, thermal comfort occurs in Tmin, but in Tmax, heat stress discomfort occurs. In the months of March and April the discomfort occurs as much by cold as by heat. Thus, for a zootechnical production and human thermal comfort in the central region of RS, it is necessary to practice environmental conditioning to minimize thermal stress.   Keywords: thermal comfort index; bioclimatic analysis; thermal amplitude.  

Thermal Imaging Product Power-up: Metrology for Capturing Thermal Defects on Live Units Not Visible on Any Other Technique

2005 ◽  
Author(s):  
Nova T. Zamora ◽  
Kam Meng Chong ◽  
Ashish Gupta
Keyword(s):  
Thermal Imaging ◽  
Thermal Response ◽  
Recent Application ◽  
Ir Camera ◽  
Thermal Failure ◽  
Response Data ◽  
Startup Process ◽  
Customer Returns ◽  
Actual Computer ◽  
Detection Of Defects

Abstract This paper presented the recent application of die powerup in Thermal Imaging as applied to the detection of defects causing thermal failure on revenue products or units not being captured using other available techniques. Simulating the condition on an actual computer setup, the infrared (IR) camera should capture images simultaneously as the entire bootup process is being executed by the processor, thus revealing a series of images and thermal information on each and every step of the startup process. This metrology gives the failure analyst a better approach to acquire a set of information that substantiate in the conduct of rootcause analysis of thermal-related failure in revenue units, especially on customer returns. Defective units were intentionally engineered in order to collect the thermal response data and eventually come up with a plot of all known thermal-related defects.

Extracellular Proteins as Enterobacterial Thermometers

2003 ◽  
Vol 86 (1-2) ◽  
pp. 139-156 ◽  
Author(s):  
Robin J. Rowbury
Keyword(s):  
Thermal Stress ◽  
Heat Shock ◽  
Stress Responses ◽  
Direct Evidence ◽  
Experimental Studies ◽  
Extracellular Proteins ◽  
Temperature Changes ◽  
Induction Components ◽  
Cellular Components ◽  
Thermal Stimuli

Biological thermometers are cellular components or structures which sense increasing temperatures, interaction of the thermometer and the thermal stress bringing about the switching-on of inducible responses, with gradually enhanced levels of response induction following gradually increasing temperatures. In enterobacteria, for studies of such thermometers, generally induction of heat shock protein (HSP) synthesis has been examined, with experimental studies aiming to establish (often indirectly) how the temperature changes which initiate HSP synthesis are sensed; numerous other processes and responses show graded induction as temperature is increased, and how the temperature changes which induce these are sensed is also of interest. Several classes of intracellular component and structure have been proposed as enterobacterial thermometers, with the ribosome and the DnaK chaperone being the most favoured, although for many of the proposed intracellular thermometers, most of the evidence for their functioning in this way is indirect. In contrast to the above, the studies reviewed here firmly establish that for four distinct stress responses, which are switched-on gradually as temperature increases, temperature changes are sensed by extracellular components (extracellular sensing components, ESCs) i.e. there is firm and direct evidence for the occurrence of extracellular thermometers. All four thermometers described here are proteins, which appear to be distinct and different from each other, and on sensing thermal stress are activated by it to four distinct extracellular induction components (EICs), which interact with receptors on the surface of organisms to induce the appropriate responses. It is predicted that many other temperature-induced processes, including the synthesis of HSPs, will be switched-on following the activation of similar extracellular thermometers by thermal stimuli.

scholarly journals Detrended Multiple Cross-Correlation Coefficient applied to solar radiation, air temperature and relative humidity

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrea de Almeida Brito ◽  
Heráclio Alves de Araújo ◽  
Gilney Figueira Zebende
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Solar Energy ◽  
Correlation Coefficient ◽  
Air Temperature ◽  
Cross Correlation ◽  
Global Solar Radiation ◽  
Meteorological Variables ◽  
Hourly Data ◽  
Cross Correlations

AbstractDue to the importance of generating energy sustainably, with the Sun being a large solar power plant for the Earth, we study the cross-correlations between the main meteorological variables (global solar radiation, air temperature, and relative air humidity) from a global cross-correlation perspective to efficiently capture solar energy. This is done initially between pairs of these variables, with the Detrended Cross-Correlation Coefficient, ρDCCA, and subsequently with the recently developed Multiple Detrended Cross-Correlation Coefficient, $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2. We use the hourly data from three meteorological stations of the Brazilian Institute of Meteorology located in the state of Bahia (Brazil). Initially, with the original data, we set up a color map for each variable to show the time dynamics. After, ρDCCA was calculated, thus obtaining a positive value between the global solar radiation and air temperature, and a negative value between the global solar radiation and air relative humidity, for all time scales. Finally, for the first time, was applied $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2 to analyze cross-correlations between three meteorological variables at the same time. On taking the global radiation as the dependent variable, and assuming that $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}={\bf{1}}$$DMCx2=1 (which varies from 0 to 1) is the ideal value for the capture of solar energy, our analysis finds some patterns (differences) involving these meteorological stations with a high intensity of annual solar radiation.

scholarly journals Effects of trees, gardens, and nature trails on heat index and child health: design and methods of the Green Schoolyards Project

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kevin Lanza ◽  
Melody Alcazar ◽  
Deanna M. Hoelscher ◽  
Harold W. Kohl
Keyword(s):  
Physical Activity ◽  
United States ◽  
Relative Humidity ◽  
Air Temperature ◽  
The United States ◽  
Heat Index ◽  
Activity Levels ◽  
Natural Setting ◽  
Physical Activity Levels ◽  
Nature Trails

Abstract Background Latinx children in the United States are at high risk for nature-deficit disorder, heat-related illness, and physical inactivity. We developed the Green Schoolyards Project to investigate how green features—trees, gardens, and nature trails—in school parks impact heat index (i.e., air temperature and relative humidity) within parks, and physical activity levels and socioemotional well-being of these children. Herein, we present novel methods for a) observing children’s interaction with green features and b) measuring heat index and children’s behaviors in a natural setting, and a selection of baseline results. Methods During two September weeks (high temperature) and one November week (moderate temperature) in 2019, we examined three joint-use elementary school parks in Central Texas, United States, serving predominantly low-income Latinx families. To develop thermal profiles for each park, we installed 10 air temperature/relative humidity sensors per park, selecting sites based on land cover, land use, and even spatial coverage. We measured green features within a geographic information system. In a cross-sectional study, we used an adapted version of System for Observing Play and Recreation in Communities (SOPARC) to assess children’s physical activity levels and interactions with green features. In a cohort study, we equipped 30 3rd and 30 4th grade students per school during recess with accelerometers and Global Positioning System devices, and surveyed these students regarding their connection to nature. Baseline analyses included inverse distance weighting for thermal profiles and summing observed counts of children interacting with trees. Results In September 2019, average daily heat index ranged 2.0 °F among park sites, and maximum daily heat index ranged from 103.4 °F (air temperature = 33.8 °C; relative humidity = 55.2%) under tree canopy to 114.1 °F (air temperature = 37.9 °C; relative humidity = 45.2%) on an unshaded playground. 10.8% more girls and 25.4% more boys interacted with trees in September than in November. Conclusions We found extreme heat conditions at select sites within parks, and children positioning themselves under trees during periods of high heat index. These methods can be used by public health researchers and practitioners to inform the redesign of greenspaces in the face of climate change and health inequities.

scholarly journals Thermal Performance of Single-Story Air-Welled Terraced House in Malaysia: A Field Measurement Approach

2020 ◽  
Vol 13 (1) ◽  
pp. 201
Author(s):  
Pau Chung Leng ◽  
Gabriel Hoh Teck Ling ◽  
Mohd Hamdan Ahmad ◽  
Dilshan Remaz Ossen ◽  
Eeydzah Aminudin ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Thermal Performance ◽  
Field Measurement ◽  
Natural Ventilation ◽  
Residential Buildings ◽  
Wet Bulb Globe Temperature ◽  
Natural Lighting ◽  
Ventilation Performance ◽  
Globe Temperature

The provision requirement of 10% openings of the total floor area stated in the Uniform Building By-Law 1984 Malaysia is essential for natural lighting and ventilation purposes. However, focusing on natural ventilation, the effectiveness of thermal performance in landed residential buildings has never been empirically measured and proven, as most of the research emphasized simulation modeling lacking sufficient empirical validation. Therefore, this paper drawing on field measurement investigates natural ventilation performance in terraced housing with an air-well system. The key concern as to what extent the current air-well system serving as a ventilator is effective to provide better thermal performance is to be addressed. By adopting an existing single-story air-welled terrace house, indoor environmental conditions and thermal performance were monitored and measured using HOBO U12 air temperature and humidity, the HOBO U12 anemometer, and the Delta Ohm HD32.3 Wet Bulb Globe Temperature meter for a six-month duration. The results show that the air temperature of the air well ranged from 27.48 °C to 30.92 °C, with a mean relative humidity of 72.67% to 79.25%. The mean air temperature for a test room (single-sided ventilation room) ranged from 28.04 °C to 30.92 °C, with a relative humidity of 70.16% to 76.00%. These empirical findings are of importance, offering novel policy insights and suggestions. Since the minimum provision of 10% openings has been revealed to be less effective to provide desirable thermal performance and comfort, mandatory compliance with and the necessity of the bylaw requirement should be revisited.

scholarly journals Quantifying the Independent Influences of Land Cover and Humidity on Microscale Urban Air Temperature Variation in Hot Summer: Methods of Path Analysis and Genetic SVR

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1377
Author(s):  
Weifang Shi ◽  
Nan Wang ◽  
Aixuan Xin ◽  
Linglan Liu ◽  
Jiaqi Hou ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Land Cover ◽  
Path Analysis ◽  
Temperature Variation ◽  
Direct Effect ◽  
Air Temperature ◽  
Urban Areas ◽  
Support Vector ◽  
Urban Air ◽  
Air Temperatures

Mitigating high air temperatures and heat waves is vital for decreasing air pollution and protecting public health. To improve understanding of microscale urban air temperature variation, this paper performed measurements of air temperature and relative humidity in a field of Wuhan City in the afternoon of hot summer days, and used path analysis and genetic support vector regression (SVR) to quantify the independent influences of land cover and humidity on air temperature variation. The path analysis shows that most effect of the land cover is mediated through relative humidity difference, more than four times as much as the direct effect, and that the direct effect of relative humidity difference is nearly six times that of land cover, even larger than the total effect of the land cover. The SVR simulation illustrates that land cover and relative humidity independently contribute 16.3% and 83.7%, on average, to the rise of the air temperature over the land without vegetation in the study site. An alternative strategy of increasing the humidity artificially is proposed to reduce high air temperatures in urban areas. The study would provide scientific support for the regulation of the microclimate and the mitigation of the high air temperature in urban areas.

scholarly journals Solar Radiation, Air Temperature, Relative Humidity, and Dew Point Study: Damak, Jhapa, Nepal

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Arun Kumar Shrestha ◽  
Arati Thapa ◽  
Hima Gautam
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Air Temperature ◽  
Gaussian Function ◽  
Great Influence ◽  
Dew Point ◽  
Upward Trend ◽  
Summer Maximum ◽  
Online Calculator ◽  
Climatic Phenomenon

Monitoring and prediction of the climatic phenomenon are of keen interest in recent years because it has great influence in the lives of people and their environments. This paper is aimed at reporting the variation of daily and monthly solar radiation, air temperature, relative humidity (RH), and dew point over the year of 2013 based on the data obtained from the weather station situated in Damak, Nepal. The result shows that on a clear day, the variation of solar radiation and RH follows the Gaussian function in which the first one has an upward trend and the second one has a downward trend. However, the change in air temperature satisfies the sine function. The dew point temperature shows somewhat complex behavior. Monthly variation of solar radiation, air temperature, and dew point shows a similar pattern, lower at winter and higher in summer. Maximum solar radiation (331 Wm-2) was observed in May and minimum (170 Wm-2) in December. Air temperature and dew point had the highest value from June to September nearly at 29°C and 25°C, respectively. The lowest value of the relative humidity (55.4%) in April indicates the driest month of the year. Dew point was also calculated from the actual readings of air temperature and relative humidity using the online calculator, and the calculated value showed the exact linear relationship with the observed value. The diurnal and nocturnal temperature of each month showed that temperature difference was relatively lower (less than 10°C) at summer rather than in winter.

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