21 research outputs found
Effect of stove asymmetric radiation field on thermal comfort using a multisegmented bioheat model
No full textThe multinode multisegment bioheat model of Salloum et al. [Salloum M, Ghaddar N, Ghali K. A new transient bio-heat model of the human body. In: Proceedings of the ASME 2005 summer heat transfer conference, 17-22 July 2005, San Francisco, Paper no. HT2005-72303] is integrated with a space heat model to study human thermal response when subjected to radiant asymmetry in stove-heated domestic spaces in Lebanon. For any given person position, the overall comfort level is based on Frank et al. model correlations [Frank SM, Srinivasa NR, Bulcao CF, Goldstein DS. Relative contribution of core and cutaneous temperatures to thermal comfort and autonomic responses in humans. Journal of Applied physiology 1999;86(5):1588-93]. The assessment of local comfort level is based on the maximum deviation of the clothed segments skin temperature from the mean skin temperature and its relation to the radiant temperature asymmetry. Experiments were run on human subjects at steady-state conditions to measure the variation of the skin temperature at different locations of the human body segments while standing in an asymmetric thermal radiation field generated by a stove-heating unit. The experiments were conducted to validate the applicability of the bioheat model in predicting skin temperature in asymmetric conditions. The measured skin temperature of various body segments and the radiative asymmetry agreed within ±5percent of values predicted by the bioheat model [Salloum M, Ghaddar N, Ghali K. A new transient bio-heat model of the human body. In: Proceedings of the ASME 2005 summer heat transfer conference, 17-22 July 2005, San Francisco, Paper no. HT2005-72303]. The space heat model and the bioheat model are applied to a case study to predict both overall thermal comfort and local thermal discomfort in a typical radiant heat space at different standing positions of the person. Strong thermal discomfort exists within the vicinity of the stove high-temperature surface. The local discomfort is considered at values of maximum SD1.1 °C derived from consideration of Fanger et al. [Fanger PO, Ipsen BM, Langkilde G, Olesen BW. Comfort limits for asymmetric thermal radiation. Energy and Buildings 1985;8(3):225-36] data of comfort limits and skin temperature measurements for asymmetric thermal radiation. © 2007 Elsevier Ltd. All rights reserved.[Anonymous], 1992, 55 ASHRAE; BERGLUND LG, 1968, ASHRAE T, V93, P497; FANGER BO, 1982, THERMAL COMFORT ANAL; Fanger P. O., 1980, ASHRAE T, V86, P141; FANGER PO, 1985, ENERG BUILDINGS, V8, P225, DOI 10.1016-0378-7788(85)90006-4; Frank SM, 1999, J APPL PHYSIOL, V86, P1588; Gan G, 2001, BUILD SERV ENG RES T, V22, P95, DOI 10.1191-014362401701524154; Ghaddar N, 2006, HEAT TRANSFER ENG, V27, P29, DOI 10.1080-01457630600742480; Ghali K, 2005, INT J GREEN ENERGY, V2, P287, DOI 10.1080-01971520500198825; Hodder SG, 1998, ENERG BUILDINGS, V27, P167, DOI 10.1016-S0378-7788(97)00038-8; HOWEL RH, 1987, RP394 ASHRAE; Huizenga C, 2001, BUILD ENVIRON, V36, P691, DOI 10.1016-S0360-1323(00)00061-5; ISO, 1984, 7730 ISO; Jones B.W., 1992, ASHRAE T, V98; Jones EC, 1998, REC ADV TOB, V24, P3; Markov D., 2002, ANN INT COURSE VENTI, P158; McNall PE, 1970, ASHRAE T, V76, P123; Miriel J, 2002, APPL THERM ENG, V22, P1861, DOI 10.1016-S1359-4311(02)00087-X; SALLOUNI M, 2005, P ASME 2005 SUMM HEA; Smith CE, 1991, THESIS KANSAS STATE; Zmeureanu R, 2003, BUILD ENVIRON, V38, P427, DOI 10.1016-S0360-1323(02)00133-644
Relevance Theory as Applied in News Headlines Translation: Ensuring Effective Communication
No full textThis paper investigates the application of Relevance Theory that was developed by cognitive scientists Dan Sperber and Deidre Wilson (1986) which suggests that human cognition is driven by the search for the most pertinent information and which is contextually appropriate for the audience. The research examines specific challenges in translating news headlines, which often give concise, culturally sensitive information that is awkward to convey effectively between languages. In order to be sure that headlines are not only accurate but also captivating and applicable for the intended audience, translators must navigate discrepancies in linguistic structure, cultural context, and audience expectations. This study enhances the effectiveness of cross-linguistic news transmission by providing translators with useful advice on handling these contextual and cognitive subtleties through the application of Relevance Theory. The results highlight how crucial cognitive factors and contextual flexibility are to overcome translation difficulties in the fast-paced news media environment, where clear and insightful communication is crucial. The study uses qualitative content analysis to investigate how translation tactics conform to the tenets of Relevance Theory. The study reveals that how implicature ,explicature and inference integrate to transmit subtle messages and influence reader’s opinions
A new transient bioheat model of the human body and its integration to clothing models
No full textA mathematical multi-segmented model based on an improved Stolwijk model is developed for predicting nude human thermal and regulatory responses within body segments and the environment. The passive model segments the body into the 15 cylindrical segments. Each body segment is divided into four nodes of core, skin, artery blood, and vein blood. In any body element, the blood exiting the arteries and flowing into the capillaries is divided into blood flowing in the core (exchanges heat by perfusion in the core) and blood flowing into the skin layer (exchanges heat by perfusion in the skin). The model calculates the blood circulation flow rates based on exact physiological data of Avolio [A.P. Avolio, Multi-branched model of the human arterial system, Med. Biol. Eng. Comp. 18 (1980) 709-718] and real dimensions and anatomic positions of the arteries in the body. The inclusion of calculated blood perfusion in the tissue is based on the pulsating arterial system model and the heart rate is unique for the current model. The nude body model is integrated to an existing clothing model based on heat and mass diffusion through the clothing layers and takes into consideration the moisture adsorption by the fibers. The bioheat human model is capable of predicting accurately nude human transient physiological responses such as the body's skin, tympanic, and core temperatures, sweat rates, and the dry and latent heat losses from each body segment. The nude and clothed body models predictions are compared with published experimental data at a variety of ambient conditions and activity. The current model agrees well with experimental data during transitions from hot to cold environments and during changes in metabolic rate. Both the nude and clothed human model have an accuracy of less than 8percent for the whole-body heat gains or losses; the nude human model has an accuracy of ± 0.48 ° C for skin temperature values. © 2006 Elsevier Masson SAS. All rights reserved.[Anonymous], 2001, ASHRAE HDB FUND; AVOLIO AP, 1980, MED BIOL ENG COMPUT, V18, P709, DOI 10.1007-BF02441895; Charny C.K., 1992, ADV HEAT TRANSFER, V2, P19; CHATO JC, 1980, J BIOMECH ENG-T ASME, V102, P110; Choi JK, 2003, INT J BIOMETEOROL, V47, P80, DOI 10.1007-s00484-002-0152-0; Craciunescu OI, 2001, J BIOMECH ENG-T ASME, V123, P500, DOI 10.1115-1.1392318; Fanger P.O., 1982, THERMAL COMFORT ANAL; FARNWORTH B, 1986, TEXT RES J, V56, P653, DOI 10.1177-004051758605601101; Fiala D, 2001, INT J BIOMETEOROL, V45, P143, DOI 10.1007-s004840100099; Fu G, 1995, THESIS KANSAS STATE; GAGGE AP, 1973, BIOASTRONAUTICS DATA; Gagge A.P., 1971, ASHRAE T 1, V77, P247; Ganong WF, 1983, REV MED PHYSL; GORDON R, 1976, IEEE T BIOMED ENG, P23; Guo ZX, 1997, INT J HEAT MASS TRAN, V40, P2486, DOI 10.1016-S0017-9310(96)00317-1; HARDY JD, 1966, J APPL PHYSIOL, V21, P1799; HARDY JD, 1966, J APPL PHYSIOL, V21, P967; HAVENITH G, 2000, J APPL PHYSIOL, V90, P1934; Henry PSH, 1939, PROC R SOC LON SER-A, V171, P0215, DOI 10.1098-rspa.1939.0062; Huizenga C, 2001, BUILD ENVIRON, V36, P691, DOI 10.1016-S0360-1323(00)00061-5; JONES BW, 1999, 33 THERM C KANS STAT; JONES BW, 1992, ASHRAE TRAN, V98, P189; JONES BW, 1994, P INT S FIB SCI TECH; Kakitsuba N, 2004, J THERM BIOL, V29, P739, DOI 10.1016-j.jtherbio.2004.08.048; LI Y, 1992, TEXT RES J, V62, P211; MILLS CJ, 1970, CARDIOVASC RES, V4, P405, DOI 10.1093-cvr-4.4.405; Milnor W., 1989, HEMODYNAMICS; Mortan WE, 1975, PHYS PROPERTIES TEXT; Nichols W W, 1998, MCDONALDS BLOOD FLOW; NORDON P, 1967, INT J HEAT MASS TRAN, V10, P853, DOI 10.1016-0017-9310(67)90065-8; PENNES HH, 1948, J APPL PHYSIOL, V1, P93; RAVEN P R, 1970, International Journal of Biometeorology, V14, P309, DOI 10.1007-BF01742075; SALAM M, 2004, THESIS AM U BEIRUT; SALTIN B, 1966, J APPL PHYSIOL, V21, P1757; SCHWARTZ CJ, 1980, STRUCTURE FUNCTION C, P1; Shitzer A, 1985, HEAT TRANSFER MED BI; Smith CE, 1991, THESIS KANSAS STATE; Stolwijk JAJ, 1970, PHYSL BEHAV TEMPERAT; STOLWIJK JA, 1966, PFLUG ARCH GES PHYS, V291, P129, DOI 10.1007-BF00412787; Tanabe S, 2002, ENERG BUILDINGS, V34, P637, DOI 10.1016-S0378-7788(02)00014-2; VALENTIN FR, 2005, HURSTS HEART; Wang X., 1994, THESIS ROYAL I TECHN; WEINBAUM S, 1984, J BIOMECH ENG-T ASME, V106, P321; WISSLER EH, 1985, HEAT MASS TRAN MED B; Womersley J. R., 1957, ELASTIC TUBE THEORY, P5645464
A new transient bio-heat model of the human body
No full textA new mathematical multi-segmented model based on an improved Stolwijk model is developed for predicting nude human thermal and regulatory responses within body segments and the environment. The passive model segments the body into the 15 cylindrical parts. Each body part is divided into four nodes of core, skin, artery blood, and vein blood. The body nodes interact with each other through convection, perfusion and conduction. In any body element, the blood exiting the arteries and flowing into the capillaries is divided into blood flowing in the core (exchanges heat by perfusion in the core) and blood flowing into the skin layer (exchanges heat by perfusion in the skin). The model calculates the blood circulation flow rates based on exact physiological data of Avolio [1], real dimensions, and anatomic positions of the arteries in the body. The circulatory system model takes into consideration the pulsatile blood flow in the macro arteries with its effect on the convective heat transport. The inclusion of calculated blood perfusion in both the tissue and the skin, based on the arterial system model and the heart rate is unique for the current model. The bio-heat human model is capable of predicting accurately nude human transient physiological responses such as the body's skin, tympanic, and core temperatures, sweat rates, and the dry and latent heat losses from each body segment. The nude body model predictions are compared with published theoretical and experimental data at a variety of ambient conditions and activity. The current model agrees well with experimental data during transient hot exposures. The nude human model has an accuracy of less than 8percent for the whole-body heat gains or losses and ±0.48°C for skin temperature values. Copyright © 2005 by ASME.*ASHRAE, 2001, HDB FUND AM SOC HEAT; AVOLIO AP, 1980, MED BIOL ENG COMPUT, V18, P709, DOI 10.1007-BF02441895; Charny C.K., 1992, ADV HEAT TRANSFER, V2, P19; CHATO JC, 1980, J BIOMECH ENG-T ASME, V102, P110; Chen M M, 1980, Ann N Y Acad Sci, V335, P137, DOI 10.1111-j.1749-6632.1980.tb50742.x; Choi JK, 2003, INT J BIOMETEOROL, V47, P80, DOI 10.1007-s00484-002-0152-0; Craciunescu OI, 2001, J BIOMECH ENG-T ASME, V123, P500, DOI 10.1115-1.1392318; Fanger PO, 1982, THERMAL COMFORT ANAL, P156; Fiala D, 2001, INT J BIOMETEOROL, V45, P143, DOI 10.1007-s004840100099; Fu G, 1995, THESIS KANSAS STATE; Gagge A.P., 1971, ASHRAE T 1, V77, P247; GAGGE AP, 1973, 2 NODE MODEL HUMAN T; Ganong WF, 1983, REV MED PHYSL; GORDON R, 1976, IEEE T BIOMEDICAL EN, V23; Guo ZX, 1997, INT J HEAT MASS TRAN, V40, P2486, DOI 10.1016-S0017-9310(96)00317-1; HAVENITH G, 2000, J APPL PHYSIOL, V90, P1934; Huizenga C, 2001, BUILD ENVIRON, V36, P691, DOI 10.1016-S0360-1323(00)00061-5; MILLS CJ, 1970, CARDIOVASC RES, V4, P405, DOI 10.1093-cvr-4.4.405; Milnor W., 1989, HEMODYNAMICS; Nichols W W, 1998, MCDONALDS BLOOD FLOW; PENNES HH, 1948, J APPL PHYSIOL, V1, P93; RAVEN P R, 1970, International Journal of Biometeorology, V14, P309, DOI 10.1007-BF01742075; SALAM M, 2004, THESIS AM U BEIRUT; SALTIN B, 1966, J APPL PHYSIOL, V21, P1757; Schwartz CJ, 1980, STRUCTURE FUNCTION C, V1; Shitzer A., 1985, HEAT TRANSFER MED BI, V1; Smith CE, 1991, THESIS KANSAS STATE; STOLWIJK JA, 1966, PFLUG ARCH GES PHYS, V291, P129, DOI 10.1007-BF00412787; Stolwijk J.A.J., 1970, PHYSL BEHAV TEMPERAT, P703; STOLWIJK JA, 1966, J APPL PHYSIOL, V21, P967; Tanabe S, 2002, ENERG BUILDINGS, V34, P637, DOI 10.1016-S0378-7788(02)00014-2; Wang X., 1994, THESIS ROYAL I TECHN; WEINBAUM S, 1984, J BIOMECH ENG-T ASME, V106, P321; WISSLER EH, 1963, SCI IND, V3, P603; Wissler EH, 1985, HEAT TRANSFER MED BI, P325; Womersley J. R., 1957, ELASTIC TUBE THEORY, P560
Relationships between selective cognitive variables and students' ability to solve chemistry problems
No full textThe purposes of this study were: to compare students' performance on conceptual and algorithmic chemistry problems; to investigate the relationships between learning orientation, formal reasoning, and mental capacity and students' performance on conceptual and algorithmic problems; and to investigate interactions among learning orientation, formal operational reasoning, and mental capacity. Participants were Grade 11 students enrolled in scientific sections of three Lebanese schools. Learning orientation, formal reasoning and mental capacities were measured using the Learning Approach Questionnaire, the Test of Logical Thinking, and the Figural Intersection Test, respectively. Also, students solved conceptual and low M-demand and high M-demand algorithmic chemistry problems. Students' performance on conceptual and algorithmic problems was compared. Regression analyses were used to examine the predictive power of the cognitive variables on each type of chemistry problems. In addition, performance of meaningful and rote learners was compared on all types of problems. Results showed that students performed significantly better on algorithmic than on conceptual problems. Moreover, meaningful learners outperformed rote learners on a test of conceptual problems while no significant differences existed for both levels of algorithmic problems. The three cognitive variables were significant predictors of performance on conceptual chemistry problems but not on algorithmic problems.ABRAHAM MR, 1994, J RES SCI TEACH, V31, P147, DOI 10.1002-tea.3660310206; ABRAHAM MR, 1992, J RES SCI TEACH, V29, P105, DOI 10.1002-tea.3660290203; Boujaoude S., 2000, SCH SCI REV, V81, P91; BOUJAOUDE SB, 1992, J RES SCI TEACH, V29, P687, DOI 10.1002-tea.3660290706; CAVALLO A, 1998, COMMUNICATION; CAVALLO A, 1991, THESIS SYRACUSE U NY; CAVALLO AML, 1994, J RES SCI TEACH, V31, P393, DOI 10.1002-tea.3660310408; Cavallo AML, 1996, J RES SCI TEACH, V33, P625, DOI 10.1002-(SICI)1098-2736(199608)33:6625::AID-TEA33.0.CO;2-Q; Entwistle N., 1983, UNDERSTANDING STUDEN; ENTWISTLE N, 1988, BRIT J EDUC PSYCHOL, V58, P258; Gage N., 1991, ED PSYCHOL; GIULIANO F, 1992, THESIS SYRACUSE U NY; Heyworth RM, 1999, INT J SCI EDUC, V21, P195, DOI 10.1080-095006999290787; LAWSON AE, 1983, J RES SCI TEACH, V20, P117, DOI 10.1002-tea.3660200204; Mason DS, 1997, J RES SCI TEACH, V34, P905, DOI 10.1002-(SICI)1098-2736(199711)34:9905::AID-TEA53.0.CO;2-Y; Nakhleh MB, 1996, J CHEM EDUC, V73, P758; NAKHLEH MB, 1993, J CHEM EDUC, V70, P52; NAKHLEH MB, 1992, J CHEM EDUC, V69, P191; NAKHLEH MB, 1993, J CHEM EDUC, V70, P190; NIAZ M, 1989, J RES SCI TEACH, V26, P785, DOI 10.1002-tea.3660260904; NIAZ M, 1989, J RES SCI TEACH, V26, P221, DOI 10.1002-tea.3660260304; NIAZ M, 1995, SCI EDUC, V79, P19, DOI 10.1002-sce.3730790103; NIAZ M, 1988, J RES SCI TEACH, V25, P643, DOI 10.1002-tea.3660250804; NIAZ M, 1993, ANN M NAT ASS RES SC; NIAZ M, 1987, J CHEM EDUC, V64, P502; NIAZ M, 1991, ANN M NAT ASS RES SC; NIAZ M, 1989, INT J SCI EDUC, V11, P93, DOI 10.1080-0950069890110109; NIAZ M, 1985, J RES SCI TEACH, V22, P41, DOI 10.1002-tea.3660220104; NIAZ M, 1988, INT J SCI EDUC, V10, P231, DOI 10.1080-0950069880100211; NIAZ M, 1992, J RES SCI TEACH, V29, P211, DOI 10.1002-tea.3660290303; NIAZ M, 1995, INT J SCI EDUC, V17, P343, DOI 10.1080-0950069950170306; Noh T, 1997, J RES SCI TEACH, V34, P199, DOI 10.1002-(SICI)1098-2736(199702)34:2199::AID-TEA63.0.CO;2-O; PICKERING M, 1990, J CHEM EDUC, V67, P254; RAMSDEN P, 1995, LEARNING TEACH HIGHE; RAMSDEN P, 1989, BRIT J EDUC PSYCHOL, V59, P129; Rop CJ, 1999, J RES SCI TEACH, V36, P221, DOI 10.1002-(SICI)1098-2736(199902)36:2221::AID-TEA73.0.CO;2-C; SAWREY BA, 1990, J CHEM EDUC, V67, P253; Tobin K., 1981, EDUC PSYCHOL MEAS, V41, P1330222
Simplified heat transport model of a wind-permeable clothed cylinder subject to swinging motion
No full textThe effect of ventilation induced by the swinging motion of a clothed cylinder in uniform wind derived from Ghaddar et al.'s periodic ventilation model is incorporated into Lotens' simple heat resistance network model to predict the mean steady periodic heat loss from the clothed cylinder. Experiments are conducted to measure the sensible heat loss from the inner cylinder for the case of a swinging inner cylinder enclosed within a clothed cylinder at different frequencies of motion and for open and closed clothing apertures at the one end of the clothed cylinder. The heat model predictions of time-averaged steady-periodic sensible heat loss agree well with the experimentally measured values at different swing frequencies between 40 and 80 rpm from experiments conducted in a controlled environmental chamber at T∞ = 25°C and relative humidity (RH) = 50percent (air velocity is less than 0.05 m-s) and in a low-speed wind tunnel (for air speed between 2 and 4 m-s). The model results showed that the rate of heat loss increased with increased ventilation frequency. Heat transfer by ventilation presented more than 50percent of total heat loss from a clothed cylinder at f = 80 rpm in the absence and presence of wind. When accurate ventilation rates of clothed swinging cylinder are estimated from first principles, the simplified heat resistance model predicted the heat loss from the isothermal cylinder surface with reasonable accuracy. The model will be a convenient tool for predicting segmental walking human body heat losses.ALOTHMANI M, 2008, INT J HEAT IN PRESS; [Anonymous], 2007, 11079 ISO; [Anonymous], 2006, 7730 ISO; [Anonymous], 2007, 9920 ISO; [Anonymous], 2002, 7933 ISO; Danielson U, 1993, THESIS ROYAL I TECHN; Fan JT, 2000, INT J HEAT MASS TRAN, V43, P2989, DOI 10.1016-S0017-9310(99)00235-5; FARNWORTH B, 1983, TEXT RES J, V53, P717, DOI 10.1177-004051758305301201; FARNWORTH B, 1986, TEXT RES J, V56, P653, DOI 10.1177-004051758605601101; Fiala D, 2001, INT J BIOMETEOROL, V45, P143, DOI 10.1007-s004840100099; Fu G, 1995, THESIS KANSAS STATE; Ghaddar N, 2005, INT J HEAT MASS TRAN, V48, P3151, DOI 10.1016-j.ijheatmasstransfer.2005.03.001; Ghaddar N, 2003, INT J THERM SCI, V42, P605, DOI 10.1016-S1290-0729(03)00026-7; GHADDAR N, 2008, ASME, V130; Ghali K, 2002, J HEAT TRANS-T ASME, V124, P530, DOI 10.1115-1.1471524; Ghali K, 2002, INT J HEAT MASS TRAN, V45, P3703, DOI 10.1016-S0017-9310(02)00088-1; Ghali K, 2006, J HEAT TRANS-T ASME, V128, P908, DOI 10.1115-1.2241811; Ghali K, 2002, J POROUS MEDIA, V5, P17; GIBSON P, 1996, NATICKTR95004 US ARM, P115; Gibson P, 2006, THERMAL AND MOISTURE TRANSPORT IN FIBROUS MATERIALS, P542, DOI 10.1533-9781845692261.3.542; GIBSON P, 1997, J SOC FIBER SCI TECH, V35, P183; HAVENITH G, 2005, P 12 INT C ENV ERG Y; HAVENITH G, 1990, ERGONOMICS, V33, P67, DOI 10.1080-00140139008927094; HAVENITH G, 1990, ERGONOMICS, V33, P989, DOI 10.1080-00140139008925308; Havenith G, 2004, EUR J APPL PHYSIOL, V92, P636, DOI 10.1007-s00421-004-1113-6; Havenith G, 2002, ENERG BUILDINGS, V34, P581, DOI 10.1016-S0378-7788(02)00008-7; Havenith G, 1999, ANN OCCUP HYG, V43, P339, DOI 10.1016-S0003-4878(99)00052-6; HAVENITH G, 2000, ENV ERGONOMICS, V10, P125; Holmer I, 1995, ANN OCCUP HYG, V39, P809, DOI 10.1016-0003-4878(95)00041-0; Huizenga C, 2001, BUILD ENVIRON, V36, P691, DOI 10.1016-S0360-1323(00)00061-5; JONES BW, 1992, ASHRAE TRAN, V98, P189; Kerslake D.M., 1972, STRESS HOT ENV; LI Y, 1992, TEXT RES J, V62, P211; Lotens WA, 1993, THESIS TNO I PERCEPT; Salloum M, 2007, INT J THERM SCI, V46, P371, DOI 10.1016-j.ijthermalsci.2006.06.017; Tanabe S, 2002, ENERG BUILDINGS, V34, P637, DOI 10.1016-S0378-7788(02)00014-2; Zhang H., 2003, THESIS U CALIFORNIA; ZHAO J, 1995, THESIS KANSAS STATE67
The optimized operation of a solar hybrid desiccant-displacement ventilation combined with a personalized evaporative cooler
No full textThe study investigates by modeling and experimentation the performance of displacement ventilation (DV) aided with personalized evaporative cooler (PEC) system that operates in humid climate and uses a solid desiccant (SD) dehumidification system regenerated by parabolic solar concentrator thermal source. Predictive component models of the conditioned space, the SD, the solar concentrator system, and the PEC were developed and used for the prediction of associated operational energy consumption while utilizing an optimized control strategy. The control strategy seeks optimal values of supply air flow rate and temperature and the desiccant regeneration temperature for both cases with and without the aid of the PEC while meeting space load, indoor air quality, and thermal comfort requirements. Energy consumption was calculated for the optimized strategy using genetic algorithm optimizer and the integrated DV-SD-PEC models. The results agreed well with experimental data obtained from tests on a DV climatic chamber. In addition, votes of comfort recorded by participants in the experiment using PEC were very similar to predicted comfort. The optimized hybrid system performance was applied to a typical office space of area of 64 m2. The operation of the hybrid system with PECs resulted in a higher supply air temperature. The increment in supply air temperature is 1.1°C when PEC is used compared to case without PEC. This increase in temperature showed that an energy saving of 13.5percent is achieved for the PEC aided hybrid system. © 2014 Copyright Taylor and Francis Group, LLC.Ahmed MH, 2005, RENEW ENERG, V30, P305, DOI 10.1016-j.renene.2004.04.010; Alice E., 2006, RELIAB ENG SYST SAFE, V91, P992; ASHRAE, 2007, 6222007 ASHRAE; Audah N, 2011, APPL ENERG, V88, P3726, DOI 10.1016-j.apenergy.2011.04.028; Ayoub M, 2007, KUWAIT J SCI ENG, V34, P107; Caldas LG, 2003, J SOL ENERG-T ASME, V125, P343, DOI 10.1115-1.1591803; Candido R. J., 2010, BUILD ENVIRON, V45, P222; Chakroun W, 2011, ENERG BUILDINGS, V43, P3250, DOI 10.1016-j.enbuild.2011.08.026; Chung J., 2008, SOL ENERGY, V83, P625; Duffie J., 2003, SOLAR ENG THERMAL PR; Fang L, 1998, INDOOR AIR, V8, P80, DOI 10.1111-j.1600-0668.1998.t01-2-00003.x; Ghali K, 2008, INT J GREEN ENERGY, V5, P360, DOI 10.1080-15435070802414280; JIANG Z, 1992, ASHRAE TRAN, V98, P33; Makhoul A, 2012, HVACandR RES, V18, P737; Makhoul A, 2013, INDOOR BUILT ENVIRON, V22, P508, DOI 10.1177-1420326X12443847; Meckler M, 1995, ASHRAE TRAN, V101, P992; Melikov AK, 2004, INDOOR AIR, V14, P157, DOI 10.1111-j.1600-0668.2004.00284.x; Mitchell M., 1997, INTRO GENETIC ALGORI; Mossolly M, 2008, ASHRAE TRAN, V114, P541; Salloum M, 2007, INT J THERM SCI, V46, P371, DOI 10.1016-j.ijthermalsci.2006.06.017; Wright JA, 2002, ENERG BUILDINGS, V34, P959, DOI 10.1016-S0378-7788(02)00071-3; Xiong ZQ, 2010, INT J GREEN ENERGY, V7, P241, DOI 10.1080-15435071003795881; Yuan X., 1998, ASHRAE T, V104, P78; Zhang H, 2010, BUILD ENVIRON, V45, P29, DOI 10.1016-j.buildenv.2009.02.016; Zhang H., 2003, THESIS U CALIFORNIA; Zheng GR, 1996, ENERGY, V21, P407, DOI 10.1016-0360-5442(96)00114-4; ZHENG W, 1993, NUMER HEAT TR A-APPL, V23, P211, DOI 10.1080-104077893089136690
Human thermal response with improved AVA modeling of the digits
No full textThe arterio-venous anastomoses (AVA) play a major role in the blood circulation in the peripheral body parts. In this work, the segmental bioheat model of Salloum et al. [1] is improved to accurately predict skin blood flow rate in the hands and fingers, and the local and overall human thermal responses in transient environments. The improvements in the model include: 1) extending the artery tree to include the arterial branching to the five fingers; 2) modeling and distribution of the blood flow between the deep and superficial veins in the peripherals; 3) adjusting arteries' radii during dilation and constriction; 4) innovative modeling of AVA of the fingers. The model focus is on the accurate blood flow calculation to the different body segments proposing a better blood control mechanism through relating the arterial tree radii as well as the AVA control mechanism to cardiac output. The skin blood flow and digits' dynamic thermal response predicted by the model were compared with published experimental values on body core and skin temperatures and local skin temperatures of fingers. Good agreement was obtained with experimentally reported values on average skin, core, and finger skin temperature response of subjects exposed to gradual decrease in air temperature from 32.3 °C to 13 °C. The new integrated AVA model of the fingers with the bioheat model is capable of predicting digits' dynamics thermal response with better accuracy than some previous models while also incorporating the complex central and local thermoregulatory functions. © 2012 Elsevier Masson SAS. All rights reserved.Arens E, 2006, THERMAL AND MOISTURE TRANSPORT IN FIBROUS MATERIALS, P560, DOI 10.1533-9781845692261.3.560; AVOLIO AP, 1980, MED BIOL ENG COMPUT, V18, P709, DOI 10.1007-BF02441895; Charkoudian N, 2003, MAYO CLIN PROC, V78, P603; Daanen H. A. M., 1991, 1991B12 TNO I PERC G; Ferreira MS, 2009, PROCEEDINGS OF THE ASME SUMMER BIOENGINEERING CONFERENCE 2008, PTS A AND B, P393; Ferreira MS, 2012, INT COMMUN HEAT MASS, V39, P196, DOI 10.1016-j.icheatmasstransfer.2011.12.004; Fiala D., 2011, INT J BIOMETEOROLOGY; Fu G, 1995, THESIS KANSAS STATE; Gordon R., 1976, IEEE T BIOMEDICAL EN, V23, P233; He Y, 2004, INT J HEAT MASS TRAN, V47, P2735, DOI 10.1016-j.ijheatmasstransfer.2003.10.041; HIRATA K, 1989, EUR J APPL PHYSIOL O, V58, P865, DOI 10.1007-BF02332220; Hodges J. G., 2009, APPL PHYSIOL NUTR ME, V34, P829; House JR, 2002, EUR J APPL PHYSIOL, V88, P141, DOI 10.1007-s00421-002-0692-3; Huizenga C, 2001, BUILD ENVIRON, V36, P691, DOI 10.1016-S0360-1323(00)00061-5; Iyoho AE, 2009, ASHRAE TRAN, V115, P484; JOHNSON JM, 1995, J APPL PHYSIOL, V78, P948; Koscheyev VS, 1998, SAE TECHNICAL PAPER, P1; Kuklane K, 2011, 14 INT C ENV ERG NAF; MELLANDE.S, 1971, ANGIOLOGICA, V8, P187; Milnor W., 1989, HEMODYNAMICS; Mowery NT, 2011, J CRITICAL CARE, V26; Nichols W. W., 1998, MCDONALDS BLOOD FLOW, p[101, 111, 246, 247]; Othmani M., 2008, INT J HEAT MASS TRAN, V51, P5522; Park Kwon Sik, 1999, Applied Human Science, V18, P233; RUBINSTEIN EH, 1990, ANESTHESIOLOGY, V73, P541, DOI 10.1097-00000542-199009000-00027; Salloum M, 2007, INT J THERM SCI, V46, P371, DOI 10.1016-j.ijthermalsci.2006.06.017; Sessler DI, 2003, EUR J APPL PHYSIOL, V89, P401, DOI 10.1007-s00421-003-0812-8; Shitzer A, 1998, J BIOMECH ENG-T ASME, V120, P389, DOI 10.1115-1.2798006; Shitzer A., 1993, ADV BIOHEAT MASS TRA, V268, P61; Shitzer A, 1997, J BIOMECH ENG-T ASME, V119, P179, DOI 10.1115-1.2796078; Smith CE, 1991, THESIS KANSAS STATE; STOLWIJK JA, 1966, J APPL PHYSIOL, V21, P967; Sun X., 2012, THESIS KANSAS STATE; Takemori T., 1995, Heat Transfer - Japanese Research, V24; Tanabe S, 2002, ENERG BUILDINGS, V34, P637, DOI 10.1016-S0378-7788(02)00014-2; Vanggaard L., 2011, 14 INT C ENV ERG NAF; WEINBAUM S, 1984, J BIOMECH ENG-T ASME, V106, P321; Xu F., 2009, APPL MECH REV, V62; Zhang H., 2003, THESIS U CALIFORNIA; Zhang HD, 2010, COMPUT BIOL MED, V40, P650, DOI 10.1016-j.compbiomed.2010.05.00325
Elderly bioheat modeling: changes in physiology, thermoregulation, and blood flow circulation
No full textA bioheat model for the elderly was developed focusing on blood flow circulatory changes that influence their thermal response in warm and cold environments to predict skin and core temperatures for different segments of the body especially the fingers. The young adult model of Karaki et al. (Int J Therm Sci 67:41-51, 2013) was modified by incorporation of the physiological thermoregulatory and vasomotor changes based on literature observations of physiological changes in the elderly compared to young adults such as lower metabolism and vasoconstriction diminished ability, skin blood flow and its minimum and maximum values, the sweating values, skin fat thickness, as well as the change in threshold parameter related to core or skin temperatures which triggers thermoregulatory action for sweating, maximum dilatation, and maximum constriction. The developed model was validated with published experimental data for elderly exposure to transient and steady hot and cold environments. Predicted finger skin temperature, mean skin temperature, and core temperature were in agreement with published experimental data at a maximum error less than 0.5 °C in the mean skin temperature. The elderly bioheat model showed an increase in finger skin temperature and a decrease in core temperature in cold exposure while it showed a decrease in finger skin temperature and an increase in core temperature in hot exposure. © 2014 ISB.Anderson GS, 1996, EUR J APPL PHYSIOL O, V73, P278, DOI 10.1007-BF02425488; ASHRAE, 1997, ASHRAE HDB FUND; AVOLIO AP, 1980, MED BIOL ENG COMPUT, V18, P709, DOI 10.1007-BF02441895; Bjerke D, 2010, TXB AGING SKIN, P159, DOI 10.1007-978-3-540-89656-2_16; Canada Centre for Occupational Health and Safety, 2008, COLD ENV HLTH EFF 1; COLLINS KJ, 1977, BRIT MED J, V1, P353; Daanen HAM, 1991, 18 TNO I PERC GROUP, p[18, B91]; Daanen HAM, 2003, EUR J APPL PHYSIOL, V89, P411, DOI 10.1007-s00421-003-0818-2; DeGroot DW, 2006, J APPL PHYSIOL, V101, P1607, DOI 10.1152-japplphysiol.00717.2006; DeGroot DW, 2007, AM J PHYSIOL-REG I, V292, pR103, DOI 10.1152-ajpregu.00074.2006; Dufour A, 2007, EUR J APPL PHYSIOL, V100, P19, DOI 10.1007-s00421-007-0396-9; Enomoto H, 1992, P 5 INT C ENV ERG MA, P120; Fiala D, 1998, THESIS MONTFORT U LE; Fiala D, 2012, INT J BIOMETEOROL, V56, P429, DOI 10.1007-s00484-011-0424-7; Fiala D, 2001, INT J BIOMETEOROL, V45, P143, DOI 10.1007-s004840100099; Fu G, 1995, THESIS KANSAS STATE; Guergova S, 2011, AGEING RES REV, V10, P80, DOI 10.1016-j.arr.2010.04.009; Hashiguchi Nobuko, 2004, Journal of Physiological Anthropology and Applied Human Science, V23, P205, DOI 10.2114-jpa.23.205; Hirata A, 2012, PHYSIOL MEAS, V33, pN51, DOI 10.1088-0967-3334-33-8-N51; Holowatz LA, 2010, J APPL PHYSIOL, V109, P1538, DOI 10.1152-japplphysiol.00338.2010; Huizenga C, 2001, BUILD ENVIRON, V36, P691, DOI 10.1016-S0360-1323(00)00061-5; Hwang RL, 2010, INDOOR AIR, V20, P235, DOI 10.1111-j.1600-0668.2010.00649.x; INOUE Y, 1992, EUR J APPL PHYSIOL O, V65, P492, DOI 10.1007-BF00602354; Iyoho AE, 2009, ASHRAE TRAN, V115, P484; Jiao J, 2012, J FIBER BIOENGINEERI, V5, P115, DOI DOI 10.3993-JFBI06201201; Karaki W, 2013, INT J THERM SCI, V67, P41, DOI 10.1016-j.ijthermalsci.2012.12.010; Keatinge WR, 2004, SOUTH MED J, V97, P1093, DOI 10.1097-01.SMJ.0000144635.07975.66; KENNEY WL, 1993, J THERM BIOL, V18, P341, DOI 10.1016-0306-4565(93)90056-Y; Kenney WL, 2003, J APPL PHYSIOL, V95, P2598, DOI 10.1152-japplphysiol.00202.2003; Nagaoka T, 2004, PHYS MED BIOL, V49, P1, DOI 10.1088-0031-9155-49-1-001; Novieto DT, 2010, P C AD CHANG NEW THI; Rida M, 2014, INT J BIOME IN PRESS; ROOKE GA, 1994, J APPL PHYSIOL, V77, P11; SAGAWA S, 1988, J GERONTOL, V43, pM1; Salloum M, 2007, INT J THERM SCI, V46, P371, DOI 10.1016-j.ijthermalsci.2006.06.017; Schellen L, 2009, P HLTH BUILD SYR 13; Schellen L, 2010, INDOOR AIR, V20, P273, DOI 10.1111-j.1600-0668.2010.00657.x; Sessler DI, 2008, ANESTHESIOLOGY, V109, P318, DOI 10.1097-ALN.0b013e31817f6d76; Smith CE, 1991, THESIS KANSAS STATE; TAYLOR NAS, 1995, J GERONTOL A-BIOL, V50, pM216; TOCHIHARA Y, 1993, J THERM BIOL, V18, P355; Tsuzuki K, 2002, P IND AIR 2002 9 INT, P647; Van Hoof J, 2006, GERONTECHNOLOGY, V4, P223, DOI 10.4017-gt.2006.04.04.006.00; Van Hoof J, 2008, P IFAS 9 GLOB C AG, P1; Vandentorren S, 2006, EUR J PUBLIC HEALTH, V16, P583, DOI 10.1093-eurpub-ck1063; van Hoof J, 2008, INDOOR AIR, V18, P182, DOI 10.1111-j.1600-0668.2007.00516.x; Van Someren EJW, 2007, AM J PHYSIOL-REG I, V292, pR99, DOI 10.1152-ajpregu.00557.2006; Waller JM, 2005, SKIN RES TECHNOL, V11, P221, DOI 10.1111-j.0909-725X.2005.00151.x; Wang D, 2007, BUILD ENVIRON, V42, P3933, DOI 10.1016-j.buildenv.2006.06.0350
A new mathematical model to simulate AVA cold-induced vasodilation reaction to local cooling
No full textThe purpose of this work was to integrate a new mathematical model with a bioheat model, based on physiology and first principles, to predict thermoregulatory arterio-venous anastomoses (AVA) and cold-induced vasodilation (CIVD) reaction to local cooling. The transient energy balance equations of body segments constrained by thermoregulatory controls were solved numerically to predict segmental core and skin temperatures, and arterial blood flow for given metabolic rate and environmental conditions. Two similar AVA-CIVD mechanisms were incorporated. The first was activated during drop in local skin temperature (andlt;32 °C). The second mechanism was activated at a minimum finger skin temperature, TCIVD, min, where the AVA flow is dilated and constricted once the skin temperature reached a maximum value. The value of TCIVD,min was determined empirically from values reported in literature for hand immersions in cold fluid. When compared with published data, the model predicted accurately the onset time of CIVD at 25 min and TCIVD,min at 10 °C for hand exposure to still air at 0 °C. Good agreement was also obtained between predicted finger skin temperature and experimentally published values for repeated immersion in cold water at environmental conditions of 30, 25, and 20 °C. The CIVD thermal response was found related to core body temperature, finger skin temperature, and initial finger sensible heat loss rate upon exposure to cold fluid. The model captured central and local stimulations of the CIVD and accommodated observed variability reported in literature of onset time of CIVD reaction and TCIVD,min. © 2014 ISB.ASHRAE, 2009, ASHRAE HDB FUND; AVOLIO AP, 1980, MED BIOL ENG COMPUT, V18, P709, DOI 10.1007-BF02441895; Bergersen TK, 1999, AM J PHYSIOL-REG I, V276, pR731; Brajkovic D, 2001, RTO HFM S BLOW HOT C; Castellani JW, 2006, MED SCI SPORT EXER, V38, P2012, DOI 10.1249-01.mss.0000241641.75101.64; Castellani JW, 2005, PREV COLD INJ M P RT; Chen F, 1996, EUR J APPL PHYSIOL O, V72, P372, DOI 10.1007-BF00599699; Cheung SS, 2007, EUR J APPL PHYSIOL, V99, P701, DOI 10.1007-s00421-006-0383-6; Daanen HAM, 1991, 1991B12 IZF TNO I PE; Daanen HAM, 1999, AVIAT SPACE ENVIR MD, V70, P1206; Daanen HAM, 2005, PREVENTION COLD INJU; Daanen HAM, 2005, AVIAT SPACE ENVIR MD, V76, P1119; Daanen HAM, 2003, EUR J APPL PHYSIOL, V89, P411, DOI 10.1007-s00421-003-0818-2; Daanen HAM, 1997, EUR J APPL PHYSIOL O, V76, P538, DOI 10.1007-s004210050287; DeGroot DW, 2003, AVIAT SPACE ENVIR MD, V74, P564; DuCharme MB, 2005, RTOMPHFM168 DEF RES; Flouris AD, 2009, J APPL PHYSIOL, V106, P1264, DOI 10.1152-japplphysiol.91426.2008; Flouris AD, 2008, EUR J APPL PHYSIOL, V104, P491, DOI 10.1007-s00421-008-0798-3; Geurts CLM, 2005, EUR J APPL PHYSIOL, V93, P524, DOI 10.1007-s00421-004-1254-7; Giesbrecht GG, 2007, AVIAT SPACE ENVIR MD, V78, P561; House JR, 2002, EUR J APPL PHYSIOL, V88, P141, DOI 10.1007-s00421-002-0692-3; Iida T, 1949, J PHYSL SOC JPN, V11, P73; ISHIGAKI H, 1993, J THERM BIOL, V18, P455, DOI 10.1016-0306-4565(93)90076-6; Iyoho AE, 2009, ASHRAE TRAN, V115, P484; JOHNSON JM, 1995, J APPL PHYSIOL, V78, P948; Kaciuba-Uscilko H, 1989, EASATB101012 NASA; Karaki W, 2013, INT J THERM SCI, V67, P41, DOI 10.1016-j.ijthermalsci.2012.12.010; Koscheyev VS, 1998, SAE TECHNICAL PAPER, P1; Kuennen MR, 2010, EUR J APPL PHYSIOL, V108, P1217, DOI 10.1007-s00421-009-1335-8; Kuklane K, 2011, 14 INT C ENV ERG NAF; Lewis T, 1930, HEART-J STUD CIRC, V15, P177; Miura T, 1977, J SCI LABOUR, V53, P75; RUBINSTEIN EH, 1990, ANESTHESIOLOGY, V73, P541, DOI 10.1097-00000542-199009000-00027; Salloum M, 2007, INT J THERM SCI, V46, P371, DOI 10.1016-j.ijthermalsci.2006.06.017; Sawada S, 1996, IND HEALTH, V34, P51, DOI 10.2486-indhealth.34.51; Sawada S, 2000, IND HEALTH, V38, P79, DOI 10.2486-indhealth.38.79; Sendowski I, 1997, EUR J APPL PHYSIOL O, V75, P471, DOI 10.1007-s004210050191; Sharp MW, 1988, PERIPHERAL CIR UNPUB; Shitzer A, 1998, J BIOMECH ENG-T ASME, V120, P389, DOI 10.1115-1.2798006; Shitzer A, 1997, J BIOMECH ENG-T ASME, V119, P179, DOI 10.1115-1.2796078; Smith CE, 1991, THESIS KANSAS STATE; Takemori T., 1995, Heat Transfer - Japanese Research, V24; Teichner W, 1966, PSYCHOPHYSIOLOGY, V2, P295, DOI 10.1111-j.1469-8986.1966.tb02657.x; van der Struijs NR, 2008, AVIAT SPACE ENVIR MD, V79, P941, DOI 10.3357-ASEM.2258.2008; Vanggaard L, 2012, CLIN PHYSIOL FUNCT I, V32, P463, DOI 10.1111-j.1475-097X.2012.01151.x; WILSON O, 1970, J APPL PHYSIOL, V29, P6580
