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1
Grohoľ, Stanislav. "Napěťová reference s LTZ1000." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242056.
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The thesis deals with the issue of stability of voltage reference based on LTZ1000(A) integrated circuit. At the beginning are specified main parameters of voltage references in terms of stability. The work presents distribution references by architecture and by method of connection to the circuit. Work compares some references of Analog Devices and Linear Technology companies. In work is described voltage reference LTZ1000(A) and its circuits from datasheet. Listed are the main factor that influence the stability of reference, such as temperature, PCB design, Zener diode bias current, airflow and choice of circuit components. Given the description of a design module with the 7 V, 5 V and 10 V output. Made was three samples of PCB. Listed are results from long-term drift and temperature drift measures.
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Bethi, Shiva Sai. "A Temperature and Process Insensitive CMOS Only Reference Current Generator." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1416406367.
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Zhang, ZiHao. "A High Temperature Reference Voltage Generator with SiC Transistors." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/72888.
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Natural resources are always collected from harsh environments, such as mines and deep wells. Currently, depleted oil wells force the gas and oil industry to drill deeper. As the industry drills deeper, temperatures of these wells can exceed 210 °C. Contemporary downhole systems have reached their depth and temperature limitations in deep basins and are no longer meet the high requirements in harsh environment industries. Therefore, robust electronic systems that can operate reliably in harsh environments are in high demand. This thesis presents a high temperature reference voltage generator that can operate reliably up to 250 °C for a downhole communication system. The proposed reference voltage generator is designed and prototyped using 4H-SiC bipolar transistors. Silicon carbide (SiC) is a semiconductor material that exhibits wide bandgap, high dielectric breakdown field strength, and high thermal conductivity. Due to these properties, it is suitable for high-frequency, high-power, and high-temperature applications. For bypassing the lack of high temperature p-type SiC transistors (pnp BJT, PMOS) and OpAmp inconvenience, an all npn voltage reference architecture has been developed based on Widlar bandgap reference concept. The proposed reference voltage generator demonstrates for the first time a functional high temperature discrete reference voltage generator that uses only five 4H-SiC transistors to achieve both temperature and supply independent. Measurement results show that the proposed voltage reference generator provides an almost constant negative reference voltage around -3.23 V from 25 °C to 250 °C regardless of any change in power supply with a low temperature coefficient (TC) of 42 ppm/°C.Master of Science
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Nukala, Utthej. "Design of a Temperature Independent MOSFET-Only Current Reference." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1319473836.
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Silva, João Gonçalo Clemente da. "Project of a bandgap voltage reference and a temperature sensor for "energy harvest" systems." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/11330.
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Dissertação para obtenção do Grau de Mestre em
Engenharia Electrotécnica e ComputadoresThe objective of this thesis is to study the behaviour of a bandgap voltage reference and develop it in order to be more efficient than the existing ones. In this case having applicability in energy harvest, the main approach for this circuit is to reduce the power dissipation and at the same time guarantee a stable of the reference voltage. This can be achieved through the utilization of MOS transistors which can work with a lower voltage then bipolar transistors. The reference voltage circuit present in this thesis can work with a supply voltage as low as 500 mV. In energy harvest systems besides the need to work with extremely low voltages, the sensitivity of the signals is very high, to temperature variation. So it was also important to work with an extended ranges of temperature. For this work it was also developed a temperature sensor so that it has applicability in various fields. The sensor works by currents generated by the bandgap voltage reference, having similar results to a dual slope integrating analogue-to-digital converter, although its operation and logic are quite different. The proposed solution is to implement a reference voltage generator powered by a voltage source of 500 mV, with a consumption of about 7 W. Having a temperature coefficient slightly below 74 ppm/ C and a temperature sensor with linearity quite satisfactory.
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Dawkins, Samuel T. "Sapphire room temperature optical frequency reference : design, construction and application." University of Western Australia. School of Physics, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0200.
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A pair of high-stability optical frequency references has been developed. The devices are based on room temperature Fabry-Perot cavities with mirrors spaced apart by a hollow single-crystal sapphire element. The sapphire element delivers mechanical sti ness that provides improved immunity to vibrational perturbations compared with the more common spacers made from ultra-low expansion glass. The system is housed in an vacuum chamber designed to provide isolation from environmental perturbations through the use of an active thermal control system, suspension legs and a unique beam alignment system. The dimensional stability of the Fabry-Perot was translated into a highly stable laser frequency by frequency locking a 1064nm Nd:YAG laser to the centre of a mode of the cavity. This frequency lock was implemented by the Pound-Drever-Hall scheme. By careful design, this control system was able to hold the frequency of the laser to within parts in 1016 of the frequency of the fundamental cavity mode. The minimum fractional frequency stability of the laser frequency was measured at 2.1x10[-]14 for integration times of 0.8 s, limited by the residual instability of the Fabry-Perot cavity. The experimental methods used to measure the performance of the system have also been considered in depth. For example, the most common way of characterizing the frequency stability of a frequency standard is the Allan variance. It is demonstrated that, without care, data taken with modern frequency counters can produce erroneous and distorted results when their output is supplied to this algorithm. The method to avoid or account for these errors is also presented. The Fabry-Perot cavity performance is limited on long timescales by residual temperature uctuations, which can be ameliorated in future by enhancing the design of the thermal control system. At short timescales, the system is limited by vibration-induced uctuations together with a white noise source, that is yet to be identi ed, but may relate to fundamental thermodynamic temperature uctuations of the sapphire spacer. This system was used to measure the stability of an optical signal synthesised from a cryogenic microwave sapphire oscillator using an wide-band optical frequency comb. This was the rst demonstration of a multiplication of an ultra-stable signal from the microwave frequency domain into the optical frequency domain, without loss of delity at the level of 2x10[-]14.
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Cameron, R. W. F. "Low temperature stress in woody perennials with special reference to rhododendron." Thesis, University of Strathclyde, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395132.
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Mudroch, Michal. "Návrh nízkonapěťového napájecího a referenčního bloku založeného na teplotně stabilní napěťové referenci." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-399479.
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In this diploma thesis there is elaborated design of low-voltage power supply block using I3T25 technology. The theoretical part describes the basic structures used in the design, using CMOS and bipolar devices. Furthermore, the properties and the analysis used in the evaluation are described. In the design part there is an elaborated design of individual parts, including voltage references, current references, DAC converter, operational amplifier. In the last part, the power supply block is subjected to simulations for verification of temperature compensated output variables and analyzed circuit functionality.
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Farage, P. K. "Chilling and freezing effects on photosynthesis and production in field crops with particular reference to photoinhibition." Thesis, University of Essex, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383552.
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Bubla, Jiří. "Band Gap - přesná napěťová reference." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217808.
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This diploma thesis is specialized on a design of a high accuracy voltage reference Bandgap. A very low temperature coefficient and output voltage approx. 1,205V are the main features of this circuit. The paper contains a derivation of the Bandgap principle, examples of realizations of the circuits and methods of compensation temperature dependence and manufacture process, design of Brokaw and Gilbert reference, design of a testchip and measurement results.
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Miri, Lavasani Seyed Hossein. "Design and phase-noise modeling of temperature-compensated high frequency MEMS-CMOS reference oscillators." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/41096.
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Frequency reference oscillator is a critical component of modern radio transceivers. Currently, most reference oscillators are based on low-frequency quartz crystals that are inherently bulky and incompatible with standard micro-fabrication processes. Moreover, their frequency limitation (<200MHz) requires large up-conversion ratio in multigigahertz frequency synthesizers, which in turn, degrades the phase-noise. Recent advances in MEMS technology have made realization of high-frequency on-chip low phase-noise MEMS oscillators possible.
Although significant research has been directed toward replacing quartz crystal oscillators with integrated micromechanical oscillators, their phase-noise performance is not well modeled. In addition, little attention has been paid to developing electronic frequency tuning techniques to compensate for temperature/process variation and improve the absolute frequency accuracy.
The objective of this dissertation was to realize high-frequency temperature-compensated high-frequency (>100MHz) micromechanical oscillators and study their phase-noise performance. To this end, low-power low-noise CMOS transimpedance amplifiers (TIA) that employ novel gain and bandwidth enhancement techniques are interfaced with high frequency (>100MHz) micromechanical resonators. The oscillation frequency is varied by a tuning network that uses frequency tuning enhancement techniques to increase the tuning range with minimal effect on the phase-noise performance. Taking advantage of extended frequency tuning range, and on-chip temperature-compensation circuitry is embedded with the sustaining circuitry to electronically temperature-compensate the oscillator. Finally, detailed study of the phase-noise in micromechanical oscillators is performed and analytical phase-noise models are derived.
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Makarowski, Kathryn Elizabeth. "An investigation of spatial and temporal variability in several of Montana's reference streams working toward a more holistic management strategy /." Diss., [Missoula, Mont.] : The University of Montana, 2009. http://etd.lib.umt.edu/theses/available/etd-08252009-120501.
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Skalický, Pavel. "Referenční zdroje napětí a proudu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219331.
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The topic of the master´s thesis are voltage and current reference sources. There is detailed description of current and voltage references, which are basic building blocks of many analog circuits, in the theoretical part. Next part of the master´s thesis is the design of a voltage reference source, the design of a voltage reference generating two voltages and a current reference source. The correct function of all circuits have been verified using simulations, especially dependence of the output voltage or current on supply voltage or dependence of the output voltage or current when the ambient temperature is changed.
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Proffitt, Geoffrey W. H. "The biology and ecology of purple moor-grass Molinia caerulea (L.) Moench. with special reference to the root system." Thesis, Aberystwyth University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.482793.
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Cunningham, Jonathan R. C. "Studies on horizontal cells of the carp retina with special reference to temperature and calcium." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5147/.
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Carp [Cyprinus carpio) were acclimated to 8±1 C, 16±1.5 C and 26±1 C. Dark adapted retinas were isolated and light induced responses of HI horizontal cells recorded. The dynamic range of these cells was affected by temperature, showing a decrease on heating or cooling from an optimum temperature. The effect of acclimation was to shift this optimum in an adaptive manner. A move from 16 C to 8 C resulted in ~44% acclimation, while a move from 16 C to 26 C resulted in ~67% acclimation. The rates of change of membrane potential and latency of the response also showed adaptive changes on acclimation. Isolated horizontal cells were voltage clamped using the whole cell patch clamp technique. The current-voltage (I-V) relationship of the prominent anomalous rectifier current was displaced by changes in the extracellular potassium concentration and was blocked by Ba(^2+) or Rb(^+). Its amplitude did not appear to be affected by thermal acclimation. A pharmacologically isolated sustained Ca(^2+) current, with an I-V relationship characteristic of an L-type current, also showed no apparent thermal acclimation. The ratiometric calcium indicator Fura-2 was used to measure the intracellular calcium concentration in isolated horizontal cells. The intracellular calcium concentration rose on depolarization of the cells, in an extracellular calcium concentration dependent manner. This increase was blocked by various metal ions with varying sensitivities: La(^3+)>Cd(^2+)>Cu(^2+)>Co≥Ni(^2+). The rate of change of intracellular calcium concentration was increased by increased temperature, but did not appear to be affected by thermal acclimation. Sustained depolarizations (up to 15 minutes) resulted in sustained elevations in intracellular calcium concentration proportional to the degree of depolarization. Possible mechanisms underlying the long and short term effects of temperature on the horizontal cell responses are discussed. The sustained calcium current and the intracellular calcium concentration changes are disscused in terms of the potential roles of this current and the significance of the subsequent intracellular calcium concentration changes.
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Degong, Dang. "Theoretical and experimental diesel engine system studies, with special reference to temperature and altitude derating." Thesis, University of Bath, 1989. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234139.
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Hermier, Yves. "Le point triple du mercure comme reference de temperature : etude, realisation et bilan des incertitudes." Paris, CNAM, 1994. http://www.theses.fr/1994CNAM0198.
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Parmi les points fixes de l'echelle internationale de temperature de 1990 (eit-90) le comite consultatif de thermometrie (cct) comite international des poids et mesures (cipm) a fait adopter le point triple du mercure. L'institut national de metrologie (inm) du conservatoire national des arts et metiers (cnam), a, parmi ses missions, celle de mettre en place cette reference nationale. Le bilan des incertitudes sur la temperature du point fixe du mercure est, a notre avis, loin d'avoir ete completement etabli. C'est pourquoi, a l'inm, nous avons etudie metrologiquement cette reference dans le but d'etablir une incertitude sur la temperature aussi realiste que possible. Les deux principales incertitudes sont: a. Les incertitudes d'origine chimique. B. Les incertitudes d'origine thermique. Nous avons realise des dispositifs particuliers pour mettre en uvre le point de mercure par une methode a flux constant et par une methode adiabatique. Nous avons compare les resultats obtenus par les deux methodes. Les travaux ont debouche sur: une comparaison internationale des differentes realisations (projet euromet n 280) l'etablissement d'un contrat de licence de commercialisation de cellules thermometriques, entre le cnam et la societe engelhard-pyrocontrole. La mise en place de la reference nationale du point de mercure, pour permettre un raccordement de toutes les mesures industrielles a cette reference nationale
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Tabrizian, Roozbeh. "Temperature-compensated silicon-based bulk acoustic resonators." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52929.
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Microelectromechanical resonators have found widespread applications in timing, sensing and spectral processing. One of the important performance metrics of MEMS resonators is the temperature sensitivity of their frequency. The main objective of this dissertation is the compensation and control of the temperature sensitivity of silicon resonators through engineering of device geometry and structural composition. This has been accomplished through formation of composite platforms or novel geometries based on dispersion characteristics of guided acoustic waves in single crystalline silicon (SCS) microstructures. Furthermore, another objective of this dissertation is to develop efficient longitudinal piezoelectric transduction for in-plane resonance modes of SCS resonators that have lithographically-defined frequencies, to reduce their motional resistance (Rm).
A uniformly distributed matrix of silicon dioxide pillars is embedded inside the silicon substrate to form a homogenous composite silicon-oxide platform (SilOx) with nearly perfect temperature-compensated stiffness moduli. Temperature-stable micro-resonators implemented in SilOx platform operating in any desired in- and out-of-plane resonance modes show full compensation of linear temperature coefficient of frequency (TCF). Overall frequency drifts as small as 80 ppm has been achieved over the industrial temperature range (-40°C to 80°C) showing a 40x improvement compared to uncompensated native silicon resonators. A 27 MHz temperature-compensated MEMS oscillator implemented using SilOx resonator demonstrated sub-ppm instability over the industrial temperature range. Besides this, a new formulation of different resonance modes of SCS resonators based on their constituent acoustic waves is presented in this dissertation. This enables engineering of the acoustic resonator to provide several resonance modes with mechanical energy trapped in central part of the resonator, thus obviating narrow tethers traditionally used for anchoring the cavity to the substrate. This facilitates simultaneous piezoelectric-transduction of multiple modes with different TCFs through independent electrical ports, which can realize highly accurate self-temperature sensing of the device using a beat frequency (fb) generated from linear combination of different modes. Piezoelectrically-transduced multi-port silicon resonators implemented using this technique provide highly temperature-sensitive fb with a large TCF of ~8500 ppm/°C showing 100x improvement compared to other Quartz/MEMS counterparts, suggesting these devices as highly sensitive temperature sensors for environmental sensing and temperature-compensated/oven-controlled crystal oscillator (TCXO/OCXO) applications.
Another part of this dissertation introduces a novel longitudinal piezoelectric transduction technique developed for implementation of low Rm silicon resonators operating in lithographically defined in-plane modes. Aluminum nitride films deposited on the sidewalls of thick silicon microstructures provides efficient electromechanical transduction required to achieve low Rm. 100 MHz SCS bulk acoustic resonators implemented using this transduction technique demonstrates Rm of 33Ω showing a 100x improvement compared to electrostatically transduced counterparts. Low-loss narrow-band filters with tunable bandwidth and frequency have been implemented by electrical coupling of these devices, showing their potential for realization of truly reconfigurable and programmable filter arrays required for software-defined radios.
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Kauser, N. "Low temperature anomalies in plastic response of crystalline materials with special reference to dilute solid solutions." Thesis, Brunel University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233340.
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Blanquart, Bertrand. "Etude et realisation d'un nouveau generateur d'air humide ; vers la definition d'une reference en temperature de rosee." Paris, CNAM, 2001. http://www.theses.fr/2001CNAM0379.
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L'humidite de l'air intervient dans de nombreux processus biologiques et physico-chimiques. La mesure de ce parametre est realisee avec differents instruments, qui doivent etre raccordes aux references nationales. La reference primaire actuelle est la methode gravimetrique, dont le domaine et les incertitudes ne satisfont pas completement les exigences des applications industrielles. Les laboratoires nationaux developpent donc d'autres methodes, basees sur la generation de la temperature de rosee, avec des efforts particuliers sur le domaine des temperatures negatives. Ce document decrit l'etude et la realisation d'un generateur d'air humide, sur le domaine de temperature de rosee de 80\c a + 15\c. Le chapitre i presente les differents principes de generateurs d'air humide et les solutions techniques mises en uvre dans les laboratoires. Deux finalites des mesures de temperature sont montrees : la premiere est la determination de la temperature de reference ; la seconde est de fournir un outil d'etude permettant d'estimer les incertitudes du generateur. Dans le chapitre ii, des solutions techniques adaptees a chacune de ces finalites sont recherchees : thermometre a resistance de platine etalon pour la determination de la temperature de reference, thermistances pour l'estimation des incertitudes. Le chapitre iii decrit la conception du generateur, basee sur la definition theorique de la temperature de rosee et integrant les contraintes liees a la reduction des incertitudes. Une methode d'estimation des incertitudes de la temperature de rosee, couplant l'utilisation des thermistances a l'analyse des echanges de chaleur et de masse dans le generateur, est presentee. Un premier bilan des incertitudes du prototype de generateur, etabli sans recours a la reference gravimetrique, constitue le chapitre iv. Un gain d'un facteur 5 sur la composante de mesure de temperature permet d'envisager une reduction significative de l'incertitude du generateur d'air humide.
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Stenton-Dozey, Jeanette Mary Edgeworth. "Physiology and energetics of the sandy-beach bivalve Donax serra Röding with special reference to temperature and chlorine tolerance." Doctoral thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/15894.
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Bibliography: pages 287-318.This thesis examines the physiology and energetics of D. serra and considers physiological responses to elevated temperature and chlorine levels typical of sea water discharged from a nuclear power station.
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Ryti, N. R. (Niilo R. I. ). "On health effects of cold spells with a special reference to sudden cardiac death." Doctoral thesis, Center for Environmental and Respiratory Health Research (CERH), 2017. http://urn.fi/urn:isbn:9789526217574.
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Abstract There is substantial evidence on the associations between cold ambient temperature and adverse health effects. Less is known about the role of prolonged episodes of cold weather denoted as cold spells. This study assessed relations between cold spells and adverse health effects globally, and quantified and elaborated the associations between cold spells and sudden cardiac death (SCD) in northern Finland. Based on random-effects models in the meta-analyses of evidence from 9 studies around the world, cold spells were associated with increased mortality rates from all or all non-accidental causes (RR 1.10; 95% CI: 1.04–1.17), cardiovascular diseases (RR 1.11; 95% CI: 1.03–1.19), and respiratory diseases (RR 1.21; 95% CI: 0.97–1.51). Suggestive evidence of other health effects was identified. Investigating 51-years of coordinate-specific weather data at the home coordinates of autopsy-verified cases of SCD, conditional logistic regression in a case-crossover setting produced an estimate for the association between cold spells and the risk of SCD (OR 1.33; 95% CI: 1.00–1.78). A greater number of cold days preceding death increased the risk of SCD approximately 19% per day (OR 1.19; 95% CI: 1.07–1.32). The association between season-specific cold spells and SCD was strongest during autumn and winter, and lowest during spring and summer. The association was stronger for ischemic (OR 1.55; 95% CI: 1.12–2.13) than for non-ischemic SCD (OR 0.68; 95% CI: 0.32–1.45) (Q-statistic 3.85, p 0.05), confirmed by the autopsy finding. Among cases suffering ischemic SCD, the association seemed stronger in those without a prior diagnosis of ischemic heart disease than in those diagnosed during lifetime. The association seemed stronger with severe coronary stenosis (OR 1.60; 95% CI: 1.11–2.30), and weaker with moderate stenosis (OR 0.97; 95% CI: 0.37–2.55). The use of aspirin, β-blockers, and nitrates seemed to decrease the risk of ischemic SCD during cold spells. In conclusion, cold spells increased the risk of ischemic SCD, and patients without appropriate diagnosis and medications for ischemic heart disease seemed most susceptible. The results indicate that coronary stenosis plays a central role in the cold-related pathogenesis of SCD. Timely diagnosis and treatment of ischemic heart disease might reduce weather-related SCDs in a communityTiivistelmä Kylmän lämpötilan ja terveyshaittojen välisistä yhteyksistä on vahva tutkimusnäyttö. Vähemmän tiedetään pitkittyneiden kylmäjaksojen ja terveyshaittojen välisistä yhteyksistä. Tutkimuksessa arvioitiin kylmäjaksojen ja terveyshaittojen välisiä yhteyksiä globaalisti, ja määritettiin kylmäjaksojen ja sydänperäisen äkkikuoleman (SÄK) välisiä yhteyksiä Pohjois-Suomessa. Yhdeksän eri puolella maailmaa toteutetun tutkimuksen tulosten meta-analyysissa satunnaisvaikutusten malli osoitti yhteyden kylmäjaksojen ja kaikkien tai luonnollisien syiden (RR 1.10; 95% CI: 1.04–1.17), sydän- ja verisuonisairauksien (RR 1.11; 95% CI: 1.03–1.19), ja hengityselimistön sairauksien (RR 1.21; 95% CI: 0.97–1.51) kuolleisuuden välillä. Viitteellistä näyttöä havaittiin muista terveyshaitoista. Tutkittaessa 51-vuoden koordinaattikohtaista säätä case-crossover-asetelmassa oikeuslääketieteellisesti vahvistettujen SÄK-tapausten kotiosoitteissa, ehdollisen logistisen regression mukaan SÄK:n riski oli yhteydessä kuolemaa edeltävään kylmäjaksoon (OR 1.33; 95% CI: 1.00–1.78). Lisääntyvä kylmien päivien lukumäärä ennen kuolemaa lisäsi riskiä keskimäärin 19% päivää kohden (OR 1.19; 95% CI: 1.07–1.32). Yhteys kausikohtaisten kylmäjaksojen ja SÄK:n välillä oli vahvin syksyllä ja talvella, ja heikoin keväällä ja kesällä. Yhteys oli vahvempi kylmäjaksojen ja iskeemisen SÄK:n (OR 1.55; 95% CI: 1.12–2.13) kuin kylmäjaksojen ja ei-iskeemisen SÄK:n (OR 0.68; 95% CI: 0.32–1.45) välillä (Q-statistic 3.85, p 0.05). Iskeemisen SÄK:n kokeneilla yhteys vaikutti vahvemmalta tapauksilla joilla ei ollut aiempaa iskeemisen sydänsairauden diagnoosia, kuin tapauksilla jotka oli diagnosoitu elinaikana. Yhteys vaikutti vahvemmalta vaikea-asteisesta sepelvaltimostenoosia sairastavilla (OR 1.60; 95% CI: 1.11–2.30), kuin lievempi-asteisessa stenoosissa (OR 0.97; 95% CI: 0.37–2.55). Aspiriini, β-salpaajat, ja nitraatit vaikuttivat vähentävän iskeemisen SÄK:n riskiä kylmäjakson aikana. Yhteenvetona, kylmäjaksot lisäsivät iskeemisen SÄK:n riskiä, ja potilaat vailla iskeemisen sydänsairauden diagnoosia ja lääkityksiä vaikuttivat olevan alttiimpia kylmäjaksojen haittavaikutuksille. Tulokset viittaavat sepelvaltimostenoosin keskeiseen rooliin kylmään liittyvän SÄK:n patogeneesissä. Varhainen iskeemisen sydänsairauden diagnoosi ja siihen liittyvä sydäntä suojaava lääkitys voisivat vähentää säähän liittyviä SÄK:a
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Borges, Ronaldo Lima Moreira. "Evapotranspiration of reference using different methodologies for the calculation of the global radiation solar, temperature and relative humidity of air." Universidade Federal do CearÃ, 2004. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2284.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoTrata-se de um estudo da estimativa da evapotranspiraÃÃo de referÃncia com a equaÃÃo de Penman-Monteith/FAO, fazendo-se uso de diferentes metodologias nos cÃlculos mÃdios diÃrios da temperatura do ar, da umidade relativa do ar e do saldo de radiaÃÃo solar. Os dados utilizados compreenderam o perÃodo de janeiro a dezembro de 2002 e foram obtidos em uma estaÃÃo meteorolÃgica automatizada, localizada no municÃpio de Paraipaba, Estado do Cearà (latitude de 3Â26â S, longitude de 39Â08â W e altitude de 31m). Para o cÃlculo das mÃdias diÃrias de temperatura e da umidade relativa do ar utilizou-se a mÃdia aritmÃtica de 24 leituras horÃrias, as equaÃÃes propostas pela FAO, pelo Instituto Nacional de Meteorologia (INMET) e pelo ServiÃo de Meteorologia do Estado de SÃo Paulo (SMESP). No cÃlculo, para obtenÃÃo do saldo de radiaÃÃo solar diÃrio, utilizaram-se as equaÃÃes de radiaÃÃo global proposta pela FAO (mÃtodo 1), por Aguiar et al. (mÃtodo 2), por Glover & McCulloch (mÃtodo 3) e por Black (mÃtodo 4). Os resultados mostram que, para a estimativa da evapotranspiraÃÃo de referÃncia com a metodologia de Penman-Monteith/FAO, podem ser utilizadas todas as equaÃÃes de temperatura mÃdia diÃria do ar apresentadas, pois o coeficiente de determinaÃÃo (RÂ) apresentou os seguintes valores quando correlacionados com o cÃlculo de ETo utilizando a mÃdia obtida pela estaÃÃo meteorolÃgica automatizada: mÃtodo FAO (0,9892), mÃtodo INMET (0,9886) e mÃtodo SMESP (0,9888). As equaÃÃes de cÃlculo da umidade relativa do ar, tambÃm, apresentaram o mesmo comportamento, sendo todas as viÃveis, obtendo-se os seguintes valores de RÂ: mÃtodo FAO (0,9972), mÃtodo INMET (0,9980) e mÃtodo SMESP (0,9817). Na estimativa do saldo de radiaÃÃo, influenciado pelas equaÃÃes apresentadas de radiaÃÃo solar global, o mÃtodo de Aguiar et al. (R = 0,3704) apresentou a maior correlaÃÃo de metodologia quando comparada com o mÃtodo da FAO.
The study was carried out in the experimental area of agribusiness Figood-ProduÃÃo de Produtos AgrÃcolas Ltda. in the Distrito de IrrigaÃÃo (irrigation district) Jaguaribe - Apodi (DIJA), Limoeiro do Norte, CearÃ, Brazil, from July to December 2008 and consisted of two experiments. In the experiment I, the treatments consisted of five irrigation frequencies: F1 - total irrigation depth applied in the morning, F2â total irrigation depth applied in the afternoon, F3 -50% of the irrigation depth applied in the morning and 50% applied in the afternoon, F4-1/3 of the irrigation depth applied in the morning, 1/3 of the irrigation depth applied at noon, 1/3 of the irrigation depth applied in the afternoon; F5 -accumulated total irrigation depth applied every two days. In the experiment II, the treatments were five different doses of nitrogen fertilizer (50, 75, 100, 125 and 150% of the standard nitrogen fertilizer recommendation) applied by fertigation, defined based in the recommended farm's fertilizer amount (from soil analysis ). The experimental design (for both experiments) was organized in randomized blocks with five treatments and four replications. In both experiments, we evaluated the following variables: plant height, plant yield, stem diameter, branch length, number of fruits per plant, fruit diameter, and fruit weight. In the first experiment the average fruit weight ranged between 52.81 and 59.05 g. In experiment II, the average fruit weight ranged between 40.00 and 63.50 g. It was also observed a direct relationship between the number of fruits per plant and plant yield. The different irrigation frequencies did not statistically influence (p > 0.05) plant height, plant yield, stem diameter, branch length, number of fruits per plant, fruit diameter, and fruit weight in the period from 0 to 190 days after the first production pruning of the fig tree cv. Roxo Valinhos. The different levels of nitrogen fertigation applied in the period from 0 to 190 days after the first production pruning of the Roxo Valinhos fig tree did not statistically influence (p > 0.05) plant height, plant yield, stem diameter, branch length, number of fruits per plant, fruit diameter, and fruit weight.
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Šenfluk, Petr. "Měření hmotnosti pomocí tenzometrů z elektronických vah." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220356.
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The aim of the thesis is weigh measurement using strain gauges from cheap digital scales. Work describes problems connected with using strain gauges as temperature compensation and requirements for accurate voltage reference and summarize function and wiring of chaep digital scales using four strain gauges. Result of work is design of an electrical circuit for weigh measurement using four strain gauges from analyzed scale.
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Toledo, Pedro Filipe Leite Correia de. "Modelamento e análise do efeito de coeficiente nulo de temperatura (ZTC) do Mosfet para aplicações análogicas de baixa sensibilidade têrmica." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/140814.
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A contínua miniaturização das tecnologias CMOS oferece maior capacidade de integração e, consequentemente, as variações de temperatura dentro de uma pastilha de silício têm se apresentado cada vez mais agressivas. Ademais, dependendo da aplicação, a temperatura ambiente a qual o CHIP está inserido pode variar. Dessa maneira, procedimentos para diminuir o impacto dessas variações no desempenho do circuito são imprescindíveis. Tais métodos devem ser incluídos em ambos fluxos de projeto CMOS, analógico e digital, de maneira que o desempenho do sistema se mantenha estável quando a temperatura oscilar. A ideia principal desta dissertação é propor uma metodologia de projeto CMOS analógico que possibilite circuitos com baixa dependência térmica. Como base fundamental desta metodologia, o efeito de coeficiente térmico nulo no ponto de polarização da corrente de dreno (ZTC) e da transcondutância (GZTC) do MOSFET são analisados e modelados. Tal modelamento é responsável por entregar ao projetista analógico um conjunto de equações que esclarecem como a temperatura influencia o comportamento do transistor e, portanto, o comportamento do circuito. Essas condições especiais de polarização são analisadas usando um modelo de MOSFET que é contínuo da inversão fraca para forte. Além disso, é mostrado que as duas condições ocorrem em inversão moderada para forte em qualquer processo CMOS. Algumas aplicações são projetadas usando a metodologia proposta: duas referências de corrente baseadas em ZTC, duas referências de tensão baseadas em ZTC, e quatro circuitos gm-C polarizados em GZTC. A primeira referência de corrente é uma Corrente de Referência CMOS Auto-Polarizada (ZSBCR), que gera uma referência de 5uA. Projetada em CMOS 180 nm, a referência opera com uma tensão de alimentação de 1.4 à 1.8 V, ocupando uma área em torno de 0:010mm2. Segundo as simulações, o circuito apresenta um coeficiente de temperatura efetivo (TCeff ) de 15 ppm/oC para -45 à +85 oC e uma sensibilidade à variação de processo de = = 4:5% incluindo efeitos de variabilidade dos tipos processo e descasamento local. A sensibilidade de linha encontrada nas simulações é de 1%=V . A segunda referência de corrente proposta é uma Corrente de Referência Sem Resistor Auto-Polarizada com Capacitor Chaveado (ZSCCR). O circuito é projetado também em 180 nm, resultando em uma corrente de referência de 5.88 A, para uma tensão de alimentação de 1.8 V, e ocupando uma área de 0:010mm2. Resultados de simulações mostram um TCeff de 60 ppm/oC para um intervalo de temperatura de -45 à +85 oC e um consumo de potência de 63 W. A primeira referência de tensão proposta é uma Referência de Tensão resistente à pertubações eletromagnéticas contendo apenas MOSFETs (EMIVR), a qual gera um valor de referência de 395 mV. O circuito é projetado no processo CMOS 130 nm, ocupando em torno de 0.0075 mm2 de área de silício, e consumindo apenas 10.3 W. Simulações pós-leiaute apresentam um TCeff de 146 ppm/oC, para um intervalo de temperatura de 55 à +125oC. Uma fonte EMI de 4 dBm (1 Vpp de amplitude) aplicada na alimentação do circuito, de acordo com o padrão Direct Power Injection (DPI), resulta em um máximo de desvio DC e ondulação Pico-à-Pico de -1.7 % e 35.8m Vpp, respectivamente. A segunda referência de tensão é uma Tensão de Referência baseada em diodo Schottky com 0.5V de alimentação (SBVR). Ela gera três saídas, cada uma utilizando MOSFETs com diferentes tensões de limiar (standard-VT , low-VT , e zero-VT ). Todos disponíveis no processo adotado CMOS 130 nm. Este projeto resulta em três diferentes voltages de referências: 312, 237, e 51 mV, apresentando um TCeff de 214, 372, e 953 ppm/oC no intervalo de temperatura de -55 à 125oC, respectivamente. O circuito ocupa em torno de 0.014 mm2, consumindo um total de 5.9 W. Por último, circuitos gm-C são projetados usando o conceito GZTC: um emulador de resistor, um inversor de impedância, um filtro de primeira ordem e um filtro de segunda ordem. Os circuitos também são simulados no processo CMOS 130 nm, resultando em uma melhora na estabilidade térmica dos seus principais parâmetros, indo de 27 à 53 ppm/°C.Continuing scaling of Complementary Metal-Oxide-Semiconductor (CMOS) technologies brings more integration and consequently temperature variation has become more aggressive into a single die. Besides, depending on the application, room ambient temperature may also vary. Therefore, procedures to decrease thermal dependencies of eletronic circuit performances become an important issue to include in both digital and analog Integrated Circuits (IC) design flow. The main purpose of this thesis is to present a design methodology for a typical CMOS Analog design flow to make circuits as insensitivity as possible to temperature variation. MOSFET Zero Temperature Coefficient (ZTC) and Transconductance Zero Temperature Coefficient (GZTC) bias points are modeled to support it. These are used as reference to deliver a set of equations that explains to analog designers how temperature will change transistor operation and hence the analog circuit behavior. The special bias conditions are analyzed using a MOSFET model that is continuous from weak to strong inversion, and both are proven to occur always from moderate to strong inversion operation in any CMOS fabrication process. Some circuits are designed using proposed methodology: two new ZTC-based current references, two new ZTC-based voltage references and four classical Gm-C circuits biased at GZTC bias point (or defined here as GZTC-C filters). The first current reference is a Self-biased CMOS Current Reference (ZSBCR), which generates a current reference of 5 A. It is designed in an 180 nm process, operating with a supply voltage from 1.4V to 1.8 V and occupying around 0:010mm2 of silicon area. From circuit simulations the reference shows an effective temperature coefficient (TCeff ) of 15 ppm/oC from 45 to +85oC, and a fabrication process sensitivity of = = 4:5%, including average process and local mismatch. Simulated power supply sensitivity is estimated around 1%/V. The second proposed current reference is a Resistorless Self-Biased ZTC Switched Capacitor Current Reference (ZSCCR). It is also designed in an 180 nm process, resulting a reference current of 5.88 A under a supply voltage of 1.8 V, and occupying a silicon area around 0:010mm2. Results from circuit simulation show an TCeff of 60 ppm/oC from -45 to +85 oC and a power consumption of 63 W. The first proposed voltage reference is an EMI Resisting MOSFET-Only Voltage Reference (EMIVR), which generates a voltage reference of 395 mV. The circuit is designed in a 130 nm process, occupying around 0.0075 mm2 of silicon area while consuming just 10.3 W. Post-layout simulations present a TCeff of 146 ppm/oC, for a temperature range from 55 to +125oC. An EMI source of 4 dBm (1 Vpp amplitude) injected into the power supply of circuit, according to Direct Power Injection (DPI) specification results in a maximum DC Shift and Peak-to-Peak ripple of -1.7 % and 35.8m Vpp, respectively. The second proposed voltage reference is a 0.5V Schottky-based Voltage Reference (SBVR). It provides three voltage reference outputs, each one utilizing different threshold voltage MOSFETs (standard-VT , low-VT , and zero-VT ), all available in adopted 130 nm CMOS process. This design results in three different and very low reference voltages: 312, 237, and 51 mV, presenting a TCeff of 214, 372, and 953 ppm/oC in a temperature range from -55 to 125oC, respectively. It occupies around 0.014 mm2 of silicon area for a total power consumption of 5.9 W. Lastly, a few example Gm-C circuits are designed using GZTC technique: a single-ended resistor emulator, an impedance inverter, a first order and a second order filter. These circuits are simulated in a 130 nm CMOS commercial process, resulting improved thermal stability in the main performance parameters, in the range from 27 to 53 ppm/°C.
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Thomas, Dylan Buxton. "Silicon-germanium devices and circuits for high temperature applications." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33949.
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Using bandgap engineering, silicon-germanium (SiGe) BiCMOS technology effectively combines III-V transistor performance with the cost and integration advantages associated with CMOS manufacturing. The suitability of SiGe technology for cryogenic and radiation-intense environments is well known, yet SiGe has been generally overlooked for applications involving extreme high temperature operation. This work is an investigation into the potential capabilities of SiGe technology for operation up to 300°C, including the development of packaging and testing procedures to enable the necessary measurements. At the device level, SiGe heterojunction bipolar transistors (HBTs), field-effect transistors (FETs), and resistors are verified to maintain acceptable functionality across the temperature range, laying the foundation for high temperature circuit design. This work also includes the characterization of existing bandgap references circuits, redesign for high temperature operation, validation, and further optimization recommendations. In addition, the performance of temperature sensor, operational amplifier, and output buffer circuits under extreme high temperature conditions is presented. To the author's knowledge, this work represents the first demonstration of functional circuits from a SiGe technology platform in ambient temperatures up to 300°C; furthermore, the optimized bandgap reference presented in this work is believed to show the best performance recorded across a 500°C range in a bulk-silicon technology platform.
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Suriyasomboon, Annop. "Herd investigations on sperm production in boars, and sow fertility under tropical conditions - with special reference to season, temperature, and humidity /." Uppsala : Dept. of Clinical Sciences, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200572.pdf.
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Joule, David. "A finite element and experimental determination of the temperature distribution in a gearbox with particular reference to machine tool thermal analysis." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329010.
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Kimmance, Susan Ann. "The interactive effects of temperature and food concentration on growth responses of aquatic protists, with particular reference to the heterotrophic dinoflagellate Oxyrrhis marina." Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250260.
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Kenyon, Eleazar Walter. "Low-noise circuitry for extreme environment detection systems implemented in SiGe BiCMOS technology." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44873.
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This work evaluates two SiGe BiCMOS technology platforms as candidates for implementing extreme environment capable circuitry, with an emphasis on applications requiring high sensitivity and low noise.
In Chapter 1, applications requiring extreme environment sensing circuitry are briefly reviewed and the motivation for undertaking this study is outlined. A case is then presented for the use of SiGe BiCMOS technology to meet this need, documenting the benefits of operating SiGe HBTs at cryogenic temperatures. Chapter 1 concludes with a brief description of device radiation effects in bipolar and CMOS devices, and a basic overview of noise in semiconductor devices and electronic components.
Chapter 2 further elaborates on a specific application requiring low-noise circuitry capable of operating at cryogenic temperatures and proposes a number of variants of band-gap reference circuits for use in said system. Detailed simulation and theoretical analysis of the proposed circuits are presented and compared with measurements, validating the techniques used in the proposed designs and emphasizing the need for further understanding of device level low-temperature noise phenomena.
Chapter 3 evaluates the feasibility of using a SiGe BiCMOS process, whose response to ionizing radiation was previously uncharacterized, for use in unshielded electronic systems needed for exploration of deep space planets or moons, specifically targeting Europa mission requirements. Measured total ionizing dose (TID) responses for both CMOS and bipolar SiGe devices are presented and compared to similar technologies. The mechanisms responsible for device degradation are outlined, and an explanation of unexpected results is proposed.
Finally, Chapter 4 summarizes the work presented and understanding provided by this thesis, concluding by outlining future research needed to build upon this study and fully realize SiGe based extreme environment capable precision electronic systems.
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Vance, Steven. "High pressure and low temperature equations of state for aqueous magnesium sulfate : applications to the search for life in extraterrestrial oceans, with particular reference to Europa /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/6825.
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Hedayati, Raheleh. "High-Temperature Analog and Mixed-Signal Integrated Circuits in Bipolar Silicon Carbide Technology." Doctoral thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-213697.
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Silicon carbide (SiC) integrated circuits (ICs) can enable the emergence of robust and reliable systems, including data acquisition and on-site control for extreme environments with high temperature and high radiation such as deep earth drilling, space and aviation, electric and hybrid vehicles, and combustion engines. In particular, SiC ICs provide significant benefit by reducing power dissipation and leakage current at temperatures above 300 °C compared to the Si counterpart. In fact, Si-based ICs have a limited maximum operating temperature which is around 300 °C for silicon on insulator (SOI). Owing to its superior material properties such as wide bandgap, three times larger than Silicon, and low intrinsic carrier concentration, SiC is an excellent candidate for high-temperature applications. In this thesis, analog and mixed-signal circuits have been implemented using SiC bipolar technology, including bandgap references, amplifiers, a master-slave comparator, an 8-bit R-2R ladder-based digital-to-analog converter (DAC), a 4-bit flash analog-to-digital converter (ADC), and a 10-bit successive-approximation-register (SAR) ADC. Spice models were developed at binned temperature points from room temperature to 500 °C, to simulate and predict the circuits’ behavior with temperature variation. The high-temperature performance of the fabricated chips has been investigated and verified over a wide temperature range from 25 °C to 500 °C. A stable gain of 39 dB was measured in the temperature range from 25 °C up to 500 °C for the inverting operational amplifier with ideal closed-loop gain of 40 dB. Although the circuit design in an immature SiC bipolar technology is challenging due to the low current gain of the transistors and lack of complete AC models, various circuit techniques have been applied to mitigate these problems. This thesis details the challenges faced and methods employed for device modeling, integrated circuit design, layout implementation and finally performance verification using on-wafer characterization of the fabricated SiC ICs over a wide temperature range.QC 20170905
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Morewood, William Dean. "Temperature/development relationships and life history strategies of Arctic Gynaephora species (Lepidoptera: Lymantriidae) and their insect parasitoids (Hymenoptera: Ichneumonidae) and (Diptera: Tachinidae) with reference to predicted global warming." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ37356.pdf.
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Cristea, Alex Florian. "Analysis of thermal effects in circumferential groove journal bearings with reference to the divergent zone." Thesis, Poitiers, 2012. http://www.theses.fr/2012POIT2313/document.
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Ce travail porte sur l'étude des effets thermiques dans un palier hydrodynamique, alimentée par une rainure circonférentielle (CGJB) sous charge statique, en tenant compte des phénomènes de rupture de film dans la zone divergente. La recherche expérimentale a été réalisée à l'Université de Poitiers ; elle a permis une détermination minutieuse des champs de pression et de température sur la portée située à l’avant d’un CGJB et dans la section médiane de sa rainure. Ces mesures sous un régime stationnaire sont originales par rapport celles existantes, quel que le type de palier, de par le grand nombre de points de mesure, 180 pour la pression et 144 pour la température, l'instrumentation de haute précision, la large plage de conditions d'exploitation (pression spécifique variant de 0,125 à 2 MPa et vitesse linéaire de l’arbre allant de 5,25 à 21 m/s). Des études du régime transitoire de démarrage au régime stationnaire établi ont été effectuées pour de faibles charges. Des expériences effectuées à l'Université "Politehnica" de Bucarest ont montré une bonne corrélation entre la perte de portance, anti-portance et la rupture du film sur un patin Rayleigh (RSP), ce qui est essentiel pour l'évaluation des phénomènes de rupture dans les paliers. Quelques modèles théoriques ont été utilisés pour évaluer les risques de serrage au démarrage qui est une instabilité thermoélastique catastrophique. Les principaux résultats sont l’obtention d’une base fiable de données expérimentales permettant le développement des modèles théoriques avancés et l’infirmation d’une répartition de pression constante dans la zone divergente et de pression et température constantes dans la rainure d'alimeThe main objective of the thesis is to study the thermal effects in steadily loaded circumferential groove journal bearings (CGJBs), including cavitation phenomena occurring in the divergent zone of such bearings. Experimental research conducted at University of Poitiers – Institut Pprime – France enabled a thorough determination of film pressure and temperature fields for the front land of a CGJB plus its mid-groove section, and several performance parameters. Measurements of film pressure and temperature fields under steady-state regime surpassed existing works, regardless of journal bearing design, through: sheer number of land measurement locations, 180 for pressure and for 144 temperature; high precision state of art instrumentation; broad range of operating conditions, 0.125 … 2 MPa specific bearing pressure and 5.25 … 21 m/s shaft speeds. Transient start-up to steady-statestabilization regimes have been investigated at low loads. Experiments at University "Politehnica" of Bucharest – Romania showed a correlation between the downforce thrust and film rupture for a Rayleigh step pin (RSP), important in evaluating divergent zone cavitation phenomena. Theoretical research consisted in developing simple models for evaluating CGJBs performance in steady-state and transient start-up regimes. Several theoretical models were employed for assessing start-up seizure, catastrophic transient thermoelastic instability and damage risk. The major result is a reliable experimental data collection that: enables development of advanced theoretical models; disprove flat film pressure distributions in divergent zones, and constant pressure and temperature in the bearing supply groov
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Callegari, Andrea. "Produzione e caratterizzazione di acqua attivata mediante plasmi freddi atmosferici per applicazioni in agricoltura." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19708/.
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This thesis is concerned with the production and characterization of PAW and its application to promote seeds germination. Two low temperature plasma devices operating at atmospheric pressure will be compared: an RF capacitively coupled source, COST Reference Microplasma Jet and another jet based on a DBD configuration, thus named DBD jet.
After plasma treatments, variations of physicochemical properties induced in PAW, such as dissolved oxygen content, electrical conductivity, pH and concentrations of the main reactive species, were measured.
Finally, the effects of the resulting solutions in enhancing germination were investigated, through the use of these liquids for the imbibition of two varieties of radish seeds (Raphanus sativus var. Sativus), chosen as model seeds.
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Angrick, Christian [Verfasser], and Matthias [Akademischer Betreuer] Bartelmann. "On the derivation of an X-ray temperature function without reference to mass and the prediction of weak-lensing number counts from the statistics of Gaussian random fields / Christian Angrick ; Betreuer: Matthias Bartelmann." Heidelberg : Universitätsbibliothek Heidelberg, 2011. http://d-nb.info/117922907X/34.
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Píšová, Petra. "Energetická certifikace systémů větrání a klimatizace v budovách." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-233806.
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The main theme of dissertation theses is systems of ventilation and air-condition used in buildings. Work consists of analyse of this systems and parameters of indoor clime whose are affected by them. It summarizes demands on the process of calculation the energy efficiency of the building services by actual legislative. On one chosen type of building is done the energy simulation of implemented systems of ventilation and air-condition by energy efficiency and their specific need of energy.
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Filho, Celso Luís de Oliveira. "Prognóstico das variáveis meteorológicas e da evapotranspiração de referência com o modelo de previsão do tempo GFS/NCEP." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/11/11131/tde-21082007-111326/.
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Avaliou-se o desempenho de um modelo numérico de previsão do tempo (GFS - Global Forecast System – antigo AVN – AViatioN model - do Centro Nacional para Previsão Ambiental – NCEP) no prognóstico de variáveis meteorológicas temperatura, déficit de pressão de vapor do ar, saldo de radiação e velocidade do vento, e da evapotranspiração de referência calculada pelos métodos de Thornthwaite (1948) e de Penman-Monteith (Allen et al., 1998). O desempenho foi avaliado por comparação com dados provenientes de uma estação meteorológica, situada em Piracicaba, São Paulo. A temperatura e o déficit de pressão de vapor do ar foram os elementos melhor prognosticados, com desempenho "muito bom" e "bom", de acordo com o índice de desempenho proposto por Camargo e Sentelhas (1997), para no máximo quatro e três dia de antecedência, respectivamente, durante o período seco. Para o período úmido, somente o prognóstico do déficit de pressão de vapor do ar para o primeiro dia mostrou-se "bom". Os prognósticos de saldo de radiação e velocidade do vento foram ruins para ambos os períodos. Em decorrência do bom desempenho do modelo para prognosticar a temperatura, verificou-se que a estimativa de ETo pelo método de Thornthwaite teve boa concordância com o calculado a partir dos dados da estação meteorológica, com antecedência de até três dias para o período seco. Para o úmido, este fato foi observado apenas para o primeiro dia de antecedência. A concordância entre os valores estimados pelo modelo e a partir da estação para o método de Penman-Monteith foi muito baixa, em conseqüência do desempenho do modelo de previsão do tempo em prognosticar o saldo de radiação e a velocidade do vento.The performance of a numeric weather forecast model (GFS- Forecast System, former AVN - AvatioN model, National Center for Environmental Prediction-NCEP) was evaluated for predicting weather variables, like air temperature and vapor pressure deficit, net radiation and wind speed, as well as reference evapotranspiration calculated by Thornthwaite (1948) and Penman-Monteith (Allen et al., 1948) methods, by the comparison with data obtained by an automatic weather station, in Piracicaba, State of São Paulo, Brazil. Temperature and vapor pressure deficit were the variables predicted with the best accuracy, with a "very good" and "good" performance, according to the index of confidence proposed by Camargo and Sentelhas (1997), for the maximum of four and three days in advance, respectively, during the dry season. For the wet season, only vapor pressure deficit was predicted with a "good" performance of the model. The predictions of net radiation and wind speed were very poor for both seasons. As the weather forecast model predicted temperature well, ETo estimated by Thornthwaite method showed a good agreement with ETo values estimated by observed data from the weather station, with till three days in advance for the dry season. For the wet season, such agreement was observed just for one day in advance. When ETo estimated by Penman-Monteith method with data from the weather forecast model and from weather station were compared any agreement was observed, which was caused by the poor performance of the numeric weather forecast model to predict net radiation and wind speed.
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Al, Khaddour Samer. "Fracture Behaviour of Steels and Their Welds for Power Industry." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-263409.
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Práce byla zaměřena na ověření platnosti koncepce master křivky pro hodnocení heterogenních svarových spojů, resp. teplotně stárnutých svarů. Současně bylo cílem disertace vyvinout kvantitativní model pro predikci referenční teploty lokalizující tranzitní oblast na teplotní ose za použití dat získaných z tahové zkoušky, a to za použití metody umělých neuronových sítí. Studie je současně zaměřena na heterogenní svarový spoj připravený tavným svařováním. Je zacílena na hodnocení lomového chování v tranzitní oblasti nejméně odolné části svaru, tj. tepelně ovlivněné zóny ferritické oceli v blízkosti zóny natavení s vysokolegovaným materiálem. Pro predikci referenční teploty master křivky je použita zmíněná metoda neuronových sítí, a to za použití dat z tahových zkoušek a měření tvrdosti. Predikovaná referenční teplota byla ověřována na základě výsledku experimentálních měření. Vytvoření modelu za použití neuronových sítí vyžaduje dostatečné množství dat a není vždy snadno tuto podmínku splnit. V případě sledovaného problému to znamenalo použití dat z dostatečně věrohodných zdrojů (skupiny Křehký lom ÚFM AVČR) a se známou metalurgickou historií. Smysl práce je tak možno spatřovat ve vývoji modelu neuronové sítě, která bude dostatečně přesně predikovat referenční teplotu. Celkově byla pro tyto účely použita data z 29 nízkolegovaných ocelí. Pro účely vývoje byly použity kromě hladkých zkušebních tyčí, rovněž tahové zkoušky s obvodovým vrubem testované při kritické teplotě křehkosti (mez makroplastických deformací) a při teplotě pokojové. Při tvorbě modelu byla postupně v různých kombinacích využita všechna data z uvedených zkoušek. Studie ukázala, že referenční teplota charakterizující tranzitní chování lomové houževnatosti oceli s převažující feritickou strukturou je jedinečným parametrem predikovatelným na základě vybraných charakteristik tahových zkoušek.
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Vousden, David Hugh Patrick. "Bahrain marine habitats and some environmental effects on seagrass beds : a study of the marine habitats of Bahrain with particular reference to the effects of water temperature, depth and salinity on seagrass biomass and distribution." Thesis, Bangor University, 1995. https://research.bangor.ac.uk/portal/en/theses/bahrain-marine-habitats-and-some-environmental-effects-on-seagrass-beds--a-study-of-the-marine-habitats-of-bahrain-with-particular-reference-to-the-effects-of-water-temperature-depth-and-salinity-on-seagrass-biomass-and-distribution(106e2056-14e0-4b61-9251-aa54eeb8b585).html.
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This thesis presents a study of the marine habitats of Bahrain together with details of some of the physical factors which may effect the distribution of those habitat types. Satellite remote sensing techniques were employed together with aerial photography and in-field 'ground-truthing' to locate 8 distinct habitat type. A comparison between the satellite-predicted habitat types and the actual habitats present reveals an accuracy of greater than 87%. Over 250 intertidal and subtidal study sites were surveyed for community type, key species, water quality measurements and seasonal variation. A final map of 12 habitat types was produced by expanding on the satellite characterisation using results from the detailed field surveys and the aerial reconnaissance. A set of sensitivity maps was drawn up to identify areas of commercial and scientific importance and to allocate areas in need of conservation, protection and management. The importance of each habitat type and its role in the overall ecosystem is discussed. The findings of this survey constitute the foundations for an effective national marine conservation strategy. Seagrass beds are identified as one of the most important habitat types around Bahrain and the effects of temperature, depth and salinity on the distribution and biomass of the three native species of seagrass are investigated. These three factors are identified as being the most variable physical factors likely to constrain seagrass growth and distribution. 14 sites were surveyed at different seasonal periods to collect data on the biomass, leaf length and leaf number of the different species of seagrass along with temperature, depth and salinity data. The leaf measurements and biomass data from the 3 species of seagrass show a clear relationship to physical factors. Temperature effects the growth of all 3 species to a varying extent. Water depth influences the distribution and growth patterns of Halodule uninervis and Halophila stipulacea. Salinity has no apparent effect on biomass or distribution. The possibility that salinity influences growth pattern and leaf morphology, particularly in Halophila ovalis, is inconclusive and would require further investigation.
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Hopcroft, Matthew A. "Temperature-stabilized silicon resonators for frequency references /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Pourkamali, Siavash. "High frequency capacitive single crystal silicon resonators and coupled resonator systems." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/26563.
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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007.Committee Chair: Ayazi, Farrokh; Committee Member: Allen, Mark; Committee Member: Brand, Oliver; Committee Member: Degertekin, Levent; Committee Member: Papapolymerou, John. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Zimouche, Hakim. "Capteur de vision CMOS à réponse insensible aux variations de température." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00656381.
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Les capteurs d'images CMOS sont de plus en plus utilisés dans le domaine industriel : la surveillance, la défense, le médical, etc. Dans ces domaines, les capteurs d'images CMOS sont exposés potentiellement à de grandes variations de température. Les capteurs d?images CMOS, comme tous les circuits analogiques, sont très sensibles aux variations de température, ce qui limite leurs applications. Jusqu'à présent, aucune solution intégrée pour contrer ce problème n'a été proposée. Afin de remédier à ce défaut, nous étudions, dans cette thèse, les effets de la température sur les deux types d'imageurs les plus connus. Plusieurs structures de compensation sont proposées. Elles reprennent globalement les trois méthodes existantes et jamais appliquées aux capteurs d'images. La première méthode utilise une entrée au niveau du pixel qui sera modulée en fonction de l'évolution de la température. La deuxième méthode utilise la technique ZTC (Zero Température Coefficient). La troisième méthode est inspirée de la méthode de la tension de référence bandgap. Dans tous les cas, nous réduisons de manière très intéressante l'effet de la température et nous obtenons une bonne stabilité en température de -30 à 125°C. Toutes les solutions proposées préservent le fonctionnement initial de l'imageur. Elles n'impactent également pas ou peu la surface du pixel
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Almotari, Masaed Moti M. "Viscosity and Density of Reference Fluid." Thesis, University of Canterbury. Physics and Astronomy, 2006. http://hdl.handle.net/10092/2065.
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The viscosity and density of bis(8-methylnonyl) benzene-1,2- dicarboxylate {diisodecyl phthalate (DIDP)}, with a nominal viscosity at T = 298 K and p = 0.1 MPa of 87 mPa•s, have been measured at temperatures from (298.15 to 423.15) K and pressures from (0.1 to 70) MPa. A vibrating wire viscometer, with a wire diameter of about 0.15 mm, was utilised for the viscosity measurements and the results have an expanded uncertainty, (k = 2), including the error arising from the pressure measurement, of between ±(2 and 2.5) % The density was determined with two vibrating tube densimeters one for operation at p≈0.1 MPa with an expanded uncertainty (k = 2) of about ±0.1 %, the other that used at pressures up to 70 MPa, with an estimated expanded uncertainty (k = 2) of about ±0.3 %. Measurements of density and viscosity were performed on three samples of DIDP each with different purity stated by the supplier and as a function of water mass fraction. The measured viscosity and density are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with the expanded (k = 2) uncertainties. The obtained viscosities at p = 0.1 MPa agree with values reported in the literature within the combined expanded (k = 2) uncertainties of the measurements while our densities differ by no more than 1.5 %. Viscosity data at p > 0.1 MPa deviate systematically from the literature values in the range of -10 % to 10 %. An apparatus capable of simultaneously measuring the solubility of a gas dissolved in a liquid and the viscosity and the density of the resulting mixture over a wide temperature and pressure range was constructed and tested. Preliminary results have been reported.
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Harris, John N. "Referenced pressure and temperature sensitive coatings using solid state phosphors /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/8577.
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Hofman, Jiří. "Testovací metody pro hodnocení radiačních efektů v přesných analogových a signálově smíšených obvodech pro aplikace v kosmické elektronice." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-401588.
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The traditional radiation testing of space electronics has been used for more than fifty years to support the radiation hardness assurance. Its typical goal is to ensure reliable operation of the spacecraft in the harsh environment of space. This PhD research looks into the radiation testing from a different perspective; the goal is to develop radiation testing methods that are focused not only on the reliability of the components but also on a continuous radiation-induced degradation of their performance. Such data are crucial for the understanding of the impact of radiation on the measurement uncertainty of data acquisition systems onboard research space missions.
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Sundaresan, Krishnakumar. "Temperature Compensated CMOS and MEMS-CMOS Oscillators for Clock Generators and Frequency References." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/13977.
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Silicon alternatives to quartz crystal based oscillators to electronic system clocking are explored. A study of clocking requirements reveals widely different specifications for different applications. Traditional CMOS oscillator-based solutions are optimized for low-cost fully integrated micro-controller clock applications. The frequency variability of these clock generators is studied and techniques to compensate for this variability are proposed. The efficacy of these techniques in reducing variability is proven theoretically and experimentally. MEMS-resonator based oscillators, due to their exceptional quality factors, are identified as suitable integrated replacements to quartz based oscillators for higher accuracy applications such as data converter clocks. The frequency variation in these oscillators is identified and techniques to minimize the same are proposed and demonstrated. The sources of short-term variation (phase noise) in these oscillators are discussed and an inclusive theory of phase noise is developed. Techniques to improve phase noise are proposed. Findings from this research indicate that MEMS resonator based oscillators, may in future, outperform quartz based solutions in certain applications such as voltage controlled oscillators. The implications of these findings and potential directions for future research are identified.
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MIRANDA, CARLOS A. de J. "Obtencao da tensao de clivagem e nivel de confiabilidade na determinacao da temperatura de referencia de acos ferriticos na transicao .Abordagem numerica experimental." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10734.
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Made available in DSpace on 2014-10-09T12:43:27Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T13:57:46Z (GMT). No. of bitstreams: 1 06630.pdf: 9701259 bytes, checksum: 3a0ddeea466df64d4d1c1cf28780f43d (MD5)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Fleming, Susannah. "Measurement and fusion of non-invasive vital signs for routine triage of acute paediatric illness." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:840d94b0-041f-4b15-8b37-c2e37c999f3e.
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Serious illness in childhood is a rare occurrence, but accounts for 20% of childhood deaths. Early recognition and treatment of serious illness is vital if the child is to recover without long-term disability. It is known that vital signs such as heart rate, respiratory rate, temperature, and oxygen saturation can be used to identify children who are at high risk of serious illness. This thesis presents research into the development of a vital signs monitor, designed for use in the initial assessment of unwell children at their first point of contact with a medical practitioner. Child-friendly monitoring techniques are used to obtain vital signs, which can then be combined using data fusion techniques to assist clinicians in identifying children with serious illness. Existing normal ranges for heart rate and respiratory rate in childhood vary considerably, and do not appear to be based on clinical evidence. This thesis presents a systematic meta-analysis of heart rate and respiratory rate from birth to 18 years of age, providing evidence-based curves which can be used to assess the degree of abnormality in these important vital signs. Respiratory rate is particularly difficult to measure in children, but is known to be predictive of serious illness. Current methods of automated measurement can be distressing, or are time-consuming to apply. This thesis therefore presents a novel method for estimating the respiratory rate from an optical finger sensor, the pulse oximeter, which is routinely used in clinical practice. Information from multiple vital signs can be used to identify children at risk of serious illness. A number of data fusion techniques were tested on data collected from children attending primary and emergency care, and shown to outperform equivalent existing scoring systems when used to identify those with more serious illness.
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Lobner, Matthew K. (Matthew Kneeland). "Enhancing SPICE model parameters to accurately design and simulate circuits with temperature dependence, with a special emphasis on bandgap references." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36567.
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