Dissertations / Theses on the topic 'Operative temperature'

The thesis deals with evaluation of the environmental thermal state in closed rooms with people inside the room. The achievement of thermal comfort is related to thermal balance of human body. People are producing heat during their work, which has to be carried away from the body to surrounding area by radiation, convection, conduction, respiration and evaporation. The intensity of heat removal is influenced by environmental parameters, especially by air temperature, mean radiant temperature, air velocity and humidity. Personal factors as energy expenditure of human body and clothing resistance are influencing the intensity of heat removal as well. People are able to influence the thermal comfort by their behaviour in given environment, appropriate clothing and regulation of basic environmental parameters. CSN EN ISO 7730 standard states that environmental parameters should be estimated or measured. The operative temperature is than evaluated from collected data. This operative temperature is defined as the temperature of black enclosed area where the human body will be by convection and radiation sharing the same amount of heat as in real inconsistent environment. Nowadays on the market there is no cheap solution for sensor which is able to evaluate the operating temperature and could be used in buildings. There are a lot of professional sensors which have very high accuracy, but are very expensive. Therefore are mainly used only for research or for single and exceptional measurement of environmental thermal state in rooms. The thesis is therefore focused on proposal of suitable (compact) operative temperature sensor assembled according to valid regulations and standards. Emphasis is placed mainly on the sensor price together with guarantee of sufficient accuracy. The proposed sensor is providing information to control system which is than able to adjust the parameters of environment using appropriate way based on relevant requirements. Here is some space for energy savings due to possible continuous measurement and evaluation of environmental thermal state in different rooms. Therefore, during continuous measurement no unnecessary rooms overheating in winter as well as unreasonable cooling in summer should occur. This research and solution is than reflected in reduction of energy consumption used for building operation and subsequently reduction of the pollutants production. This issue is being watched with increasing interest. Another advantage is that whole system is able to work autonomously without human intervention. People no longer have to continuously adjust air temperature because the control system is able to evaluate the most appropriate adjustments based on objective data obtained from the sensor. The thesis includes subsequent verification of proposed sensor as well as the definition of sensor technical parameters including analysis of measurement uncertainties.

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2011.<br>Includes bibliography.<br>ENGLISH ABSTRACT: Thermal ecology is a central theme in reptilian biology because of the thermodynamic rate dependence of virtually all biological processes in these ectothermic animals. Thermoregulation includes active processes (with associated energetic costs related to altered behaviour and physiology) functioning to maintain body temperatures within a preferred temperature range, so that the majority of physiological functions occurs optimally, despite natural variation in the animal’s thermal habitat. The recent development of quantitative thermal indices now allows researchers to describe the thermal habitat and thermoregulatory functioning of an ectotherm within its environment from a cost-benefit perspective. The use of such quantitative biophysical approaches to reptile thermal ecology studies is however limited in the African context. Cordylus cataphractus is one of the best studied cordylids, and exhibits various characteristics atypical for the family, such as permanent group-living, seasonally lowered surface activity, a low resting metabolic rate and large fat bodies. These characteristics are generally thought to be associated with groupliving in a semi-arid habitat, yet, the possible links to thermal ecology remains unexplored. The objectives of the current study was: firstly, to characterize the preferred temperature range (Tp) of C. cataphractus through the use of ecologically realistic laboratory thermal gradients; secondly, to explore seasonal and geographical variation in thermal preference, by comparing Tp among individuals captured from a coastal and inland population and during different seasons (autumn and spring); thirdly, to describe the thermal habitat of a C. cataphractus population during summer, autumn, winter and spring and to then relate these findings to the seasonal activity patterns reported in literature for the species; fourthly, to describe the seasonal patterns of thermoregulation (during summer, autumn, winter and spring) in a C. cataphractus population through quantitative thermoregulatory indices; fifthly, to assess geographic variation in the thermal habitat and IV associated patterns of thermoregulation in C. cataphractus among a coastal population (western range limit) and an inland population (eastern range limit). The thermal habitat of C. cataphractus was described by measuring operative environmental temperatures (Te) with hollow copper lizard models placed around rocks according to the natural surface movement patterns of the species. Variation in thermal habitat quality was subsequently calculated (de = |Te – Tp|) and averaged. Field body temperatures (Tb) of lizards were measured with dorsally attached miniature temperature loggers. Thermoregulatory indices were calculated from Te, Tb and Tp, describing: thermoregulatory accuracy, the effectiveness of thermoregulation and thermal exploitation for each population (coastal and inland) for the respective sampling periods. The preferred body temperature range of C. cataphractus is the lowest recorded among cordylids to date (mean Tp = 29.8oC) and was conserved among different populations and within these populations among seasons, despite the fact that environmental temperatures are known to vary geographically and seasonally. Thermal habitat quality varied significantly at micro spatial scale around rocks in the coastal population. Since C. cataphractus males are territorial, competition for thermal habitat quality around rocks may therefore occur. Such effects will be a function of the time of year since the variability in thermal habitat quality among rock aspects (around rocks) varied seasonally. Thermal habitat quality of crevices varied among seasons and was typically higher in the open, outside rock crevices, during the cooler winter and spring periods, whereas in summer and autumn the crevice environments were more favourable. Thermal habitat quality was high in crevices during autumn, suggesting that the observed repressed surface activity of C. cataphractus described for the time is not necessarily, as previously thought, only due to food constraints. Moreover, in contrast to earlier reports, the current results (Tb versus Te) indicate that individuals emerged from crevices in summer. The geographical assessment indicated that lizards from the coastal population, with generally larger groups, thermoregulated more successfully than those from the inland population. The higher thermoregulatory success in the coastal population occurred in spite of the fact that thermal habitat quality was significantly lower at the coastal locality. The higher thermoregulatory success in the coastal population was likely due to reduced predation risk associated with increased group-size. The seasonal trends in thermoregulation at the coastal and inland population corresponded to the patterns predicted by the cost-benefit model of thermoregulation, accuracy of thermoregulation and the effectiveness of thermal exploitation being higher during the thermally more favourable autumn.<br>AFRIKAANSE OPSOMMING: Uittreksel Termiese ekologie is ‘n sentrale tema in reptiel-biologie as gevolg van die termodinamies tempo-afhanklikheid van feitlik alle biologiese prosesse in hierdie ektotermiese diere. Termoregulering sluit aktiewe prosesse (wat lei tot energie-koste in terme van gedrag en fisiologie) in om liggaamstemperature binne ‘n vasgestelde voorkeurtemperatuur-reeks te handhaaf sodat fisiologiese prosesse optimaal kan geskied te midde van natuurlike variasie in die dier se termiese omgewing. Die onlangse ontwikkeling van kwantitatiewe funksionele termiese indekse stel navorsers nou in staat om die werklike termiese omgewing en die funksionering van die ektoterm binne sy omgewing te beskryf en uit ‘n koste (energie)- voordeel oogpunt te verstaan. Die gebruik van hierdie biofisiese koste-voordeel benadering in reptiel termoreguleringstudies is egter beperk in die Afrika-konteks. Cordylus cataphractus is een van die bes bestudeerde lede van familie Cordylidae, en vertoon verskeie eienskappe ongewoon vir hierdie groep akkedisse, soos groeplewendheid, beperkte seisoenale aktiwiteit buite hul skeure, ‘n relatiewe lae rustende metaboliese tempo en relatiewe groot vetliggame. Hierdie unieke eienskappe is al deur navorsers gekoppel aan die groeplewe lewensstrategie. Die potensiële koppeling van die termiese ekologie en die spesifieke lewensstrategie van C. cataphractus benodig verdere studie. Die doelwitte van hierdie studie was eerstens: om die voorkeurtemperatuur-reeks (Tp) van C. cataphractus te bepaal deur van ekologies-realistiese termiese gradiënte in die laboratorium gebruik te maak; tweedens: om geografiese en seisoenale variasie in Tp te ondersoek deur individue te gebruik wat uit binnelandse en kus-populasies, tydens verskillende seisoene, herfs en lente versamel is; derdens: om die termiese omgewing, meer spesifiek die variasie in termiese kwaliteit, binne die habitat van C. cataphractus populasie in verskillende seisoene, somer, herfs, winter en lente, te moduleer en met die gedokumenteerde aktiwiteitspatrone in verband te bring; vierdens: om die seisoenale temoreguleringspatrone (tydens somer, herfs, winter en lente) van C. cataphractus populasie te beskryf; vyfdens: om geografiese variasie in die termiese habitat en geassosieerde termoreguleringspatrone tussen kus-populasie (westelike VII verspreidingsgrens) en binneland-populasie (oostelike verspreidingsgrens) te bestudeer. Die kwaliteit van die termiese habitat van C. cataphractus is bepaal deur hol koper-modelle van akkedisse (operatiewe temperatuur modelle (Te)) te plaas rondom rotse in ooreenstemming met die natuurlike bewegingspatrone van die akkedisse. Die termiese kwaliteit is gevolglik afgelei (de = |Te – Tp|) en gemiddeldes bereken. Die liggaamstemperature (Tb) van vrylopende akkedisse in die veld is met dorsaal-gemonteerde miniatuur temperatuur “data-loggers” gemeet. Termiese indekse (deur Te, Tb en Tp te gebruik) is bereken om die akkuraatheid en effektiwiteit van termoregulering, sowel as termiese benutting van die omgewing vir beide populasies (kus en binneland) tydens verskillende seisoene te beraam. Die voorkeurtemperatuur-reeks van C. cataphractus is die laagste gedokumenteerde temperature vir enige lid van die familie Cordylidae tot op hede bestudeer (gemiddeld van Tp = 29.8oC), en het ten spyte van die feit dat omgewingstemperature wissel op geografiese en seisoenale vlakke, min gevarieer tussen die twee populasies asook tydens verskillende seisoene binne die populasies. Die termiese kwaliteit het beduidend gevarieer tussen seisoene en binne die mikroruimtelike omgewing rondom rotse in die kus-populasie. Aangesien C. cataphractus mannetjies territoriaal is, word die aanname gemaak dat kompetisie vir ‘n ruimtelike posisie ook ‘n termiese koste mag hê aangesien daar beduidende variasie in de om die rotse was. Variasie in termiese kwaliteit rondom rotse was verder ook funksie van die tyd van die jaar (seisoene). Die termiese kwaliteit van skeure het gevarieer tussen seisoene, en termiese kondisies/toestande was oor die algemeen meer gunstig buite die rots-skeure tydens die koeler winter en lente tydperke, terwyl skeure termies meer gunstig was in die somer en herfs maande. Termiese habitat kwaliteit van skeure was besonders hoog gedurende die herfs, en die voorspelling is dus dat die verlaagde oppervlak-aktiwiteit wat gedurende hierdie tyd van die jaar vir C. cataphractus gedokumenteer is nie noodwendig funksie van beperkte voedselbeskikbaarheid is nie. Teenstrydig met gepubliseerde aktiwiteitsrekords dui die resultate (Tb teenoor Te) verder daarop dat individue wel uit skeure kom tydens die warm somer seisoen. Die geografiese ondersoek het gewys dat akkedisse van die kus-populasie (wat gewoonlik uit groter groepe bestaan), meer akkuraat getermoreguleer het as akkedisse van die binneland-populasie. Die hoër akkuraatheid van termoregulering in die kus-populasie is bewerkstellig ten spyte van die feit dat die termiese kwaliteit beduidend laer was as die van die binneland-populasie. Die hoër termoreguleringsakkuraatheid in die kus-populasie kan waarskynlik toegeskryf word aan laer predasie-risiko geassosieer met groter groepe. Die seisoenale variasie-patroon van termoregulering kan verklaar word deur die koste-voordeel model van termoregulering, waarvolgens die akkuraatheid van termoregulering sowel as termiese benutting hoër is tydens periodes van hoë termiese kwaliteit (i.e. herfs).

Made available in DSpace on 2014-06-11T19:22:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-01Bitstream added on 2014-06-13T18:08:52Z : No. of bitstreams: 1 bovo_rp_me_sjrp.pdf: 510815 bytes, checksum: bcd7a1e15ce55c75992debce1daffe04 (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Dada a importância da temperatura na maior parte dos processos biológicos, estudos sobre a termorregulação têm desempenhado importante papel no entendimento sobre a ecologia dos vertebrados ectotérmicos. Em serpentes, como em outros ectotérmicos, o controle da temperatura corpórea (Tc) é dependente da utilização de fontes externas de calor e principalmente de ajustes comportamentais, embora ajustes fisiológicos e morfológicos também ocorram. Em geral, esse controle é alcançado por meio da escolha de ambientes quentes ou frios, cuja disponibilidade pode variar ao longo do dia e das estações do ano. A termorregulação, portanto, constitui aspecto central da biologia das serpentes, as quais dedicam porção considerável de seu tempo e energia a essa atividade. Os objetivos do presente estudo foram documentar a variação sazonal e circadiana da temperatura corpórea da jararaca-ilhoa, Bothrops insularis, em seu ambiente natural, a Ilha da Queimada Grande (IQG), a fim de prover análise descritiva da Tc e do comportamento termorregulatório destes animais à luz dos custos e benefícios da regulação da Tc na região tropical; e entender como estes parâmetros são ditados/influenciados por fatores ambientais (temperatura local e de microhábitats, umidade relativa, precipitação, radiação solar, vento, características do substrato) e bióticos (tamanho dos indivíduos, sexo, estágio reprodutivo, estado digestivo). (1) As jararacas-ilhoa são usualmente termoconformadoras, embora consigam atingir a temperatura corpórea preferida em todas as estações do ano; (2) as temperaturas ambientais indicam que a IQG é um ambiente termicamente favorável para essas serpentes; (3) a Tc destes animais sofre forte influência da variação sazonal e circadiana da temperatura ambientel...<br>Given the pervasive effects of temperature on most biological processes, studies focusing on thermoregulation are pivotal to the understanding of ectotherm’s vertebrate ecology. In snakes, like other ectotherms, body temperature (Tb) control is dependent of external heat sources and based mainly on behavioral adjustments, although physiological and/or morphological adjustments can also occur. In general, such control is achieved through the choice of warm or cold environments, whose availability may vary along the days and/or seasons. Thus, thermoregulation can be regarded as a central aspect of snake biology, and these animals invest considerable time and energy into this activity. The aims of the present study were to document the seasonal and circadian variation in the Tb’s of the golden lancehead, Bothrops insularis, in its natural habitat, the Queimada Grande Island (QGI). We then used such database to provide a descriptive analysis of Tb variation and thermoregulatory behavior for this species in the light of the costs-benefits theory applied to a tropical region. Our second goal was to understand how body temperature is dictated/influenced by environmental (local and microhabitat temperatures, relative humidity, precipitation, solar radiation, wind, substrate characteristics) and biotic factors (individual size, sex, reproductive stage, digestive state). The main findings of the present study were: (1) Golden lanceheads can be regarded as being thermoconformers, although they do reach their preferred body temperature in all seasons; (2) environmental temperatures indicate that QGI has a high thermal quality, i.e., it is thermically suitable for the snakes; (3) Tb is strongly influenced by seasonal and diel variation of the environmental temperature; (4) B. insularis selected... (Complete abstract click electronic access below)

Teplota vzduchu je nejčastěji používaná k posouzení tepelného stavu vnitřního prostředí. Avšak teplota vzduchu sama o sobě, je v mnoha případech pro toto posouzení nedostatečná. Hlavním cílem disertační práce je vyhodnotit tepelný stav vnitřního prostředí a specifikovat parametry, které na něj mají vliv. Teplota vzduchu, střední radiantní teplota, rychlost vzduchu a vlhkost vzduchu jsou čtyři základní parametry, které určují tepelný stav vnitřního prostředí. Vzhledem k tomu, že tepelný stav prostředí závisí na mnoha aspektech, byly odvozeny veličiny, které zahrnují kombinovaný účinek několika nebo všech těchto parametrů k určení tepelného stavu prostředí. Jedná se např. o efektivní teplotu, teplotu kulového teploměru, operativní teplotu, ekvivalentní teplotu, PMV a PPD indexy... aj. V dnešní době existuje spousta vysoce přesných senzorů, které mohou zhodnotit tepelný stav vnitřního prostředí. Z důvodu jejich vysoké ceny jsou používané převážně pro účely výzkumu. Předkládaná práce se převážně soustředí na vývoj kompaktního deskového senzoru pro vyhodnocení tepelného stavu vnitřního prostředí. Zaměřuje se hlavně na nízkou cenu senzoru společně s dostatečnou přesností. K dosažení cíle této práce jsou provedeny následující postupy: • Analýza environmentálních faktorů ovlivňujících tepelný stav prostředí. • Studium dopadu teploty vzduchu, střední radiantní teploty a rychlosti proudění vzduchu na tepelné indexy: teplotu kulového teploměru a operativní teplotu. • Teoretické porovnání teploty kulového teploměru a operativní teploty. • Navržení, rozvoj a konstrukce nového deskového senzoru pro posouzení tepelného stavu vnitřního prostředí. • Navržení a konstrukce testovací komory pro porovnávání senzorů tepelného stavu prostředí. • Kalibrace zkonstruovaného senzoru měřením fyzikálních veličin charakterizujících tepelný stav prostředí. • Testy směrové závislosti vyvinutého deskového senzoru a porovnání s kulovým teploměrem v testovací komoře. • Srovnání teoretických řešení s provedenými měřeními v testovací komoře. Výsledkem této práce je vlastní teoretické srovnání teploty kulového teploměru a operativní teploty ve vybraném rozsahu teploty vzduchu, střední radiantní teploty a rychlosti vzduchu pro možnost hodnocení tepelného stavu vnitřního prostředí pomocí kulového teploměru. Hlavním výstupem je však navržení a zhotovení jednoduchého deskového senzoru, který by byl dostatečně přesný pro měření tepelného stavu prostředí. V rámci disertace byla postavena také testovací komora a bylo provedeno testování vyvinutého senzoru pomocí měřicího systému INNOVA.