Bibliographies thématiques / Optimal temperature control

Littérature scientifique sur le sujet « Optimal temperature control »

Auteur : Grafiati
Publié le 25 mai 2024

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Articles de revues sur le sujet "Optimal temperature control"

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Tian-Yu, Liu, Cao Jia-Hui, Liu Yan-Yan, Gao Tian-Fu et Zheng Zhi-Gang. « Optimal control of temperature feedback control ratchets ». Acta Physica Sinica 70, no 19 (2021) : 190501. http://dx.doi.org/10.7498/aps.70.20210517.

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Schwalbe, Karsten, et Karl Heinz Hoffmann. « Optimal Control of an Endoreversible Solar Power Plant ». Journal of Non-Equilibrium Thermodynamics 43, no 3 (26 juillet 2018) : 255–71. http://dx.doi.org/10.1515/jnet-2018-0021.

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AbstractWhile in the classic Curzon–Ahlborn and Novikov engines the temperatures of the heat baths are kept fixed or follow a deterministic time function, it is the aim of this work to study the impact of fluctuating heat bath temperatures. As an example serves a solar power plant, where the stochastically varying cloud cover leads to fluctuations in the temperature of the hot heat bath. This solar thermal power plant is modeled as a stochastic endoreversible system. On the basis of this model the maximum expected work output of the power plant and the corresponding optimal control policy is derived. For the considered system it is found that the maximum expected work output changes with the reversion speed of the hot temperature depending on the relation of the starting hot temperature and the temperature of the power plant’s receiver. Additionally, it is found that the maximum expected work output increases with the hot temperature’s fluctuation strength.
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Agusto, Folashade B. « Optimal Control and Temperature Variations of Malaria Transmission Dynamics ». Complexity 2020 (28 novembre 2020) : 1–32. http://dx.doi.org/10.1155/2020/5056432.

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Malaria is a Plasmodium parasitic disease transmitted by infected female Anopheles mosquitoes. Climatic factors, such as temperature, humidity, rainfall, and wind, have significant effects on the incidence of most vector-borne diseases, including malaria. The mosquito behavior, life cycle, and overall fitness are affected by these climatic factors. This paper presents the results obtained from investigating the optimal control strategies for malaria in the presence of temperature variation using a temperature-dependent malaria model. The study further identified the temperature ranges in four different geographical regions of sub-Saharan Africa, suitable for mosquitoes. The optimal control strategies in the temperature suitable ranges suggest, on average, a high usage of both larvicides and adulticides followed by a moderate usage of personal protection such as bednet. The average optimal bednet usage mimics the solution profile of the mosquitoes as the mosquitoes respond to changes in temperature. Following the results from the optimal control, this study also investigates using a temperature-dependent model with insecticide-sensitive and insecticide-resistant mosquitoes the impact of insecticide-resistant mosquitoes on disease burden when temperature varies. The results obtained indicate that optimal bednet usage on average is higher when insecticide-resistant mosquitoes are present. Besides, the average bednet usage increases as temperature increases to the optimal temperature suitable for mosquitoes, and it decreases after that, a pattern similar to earlier results involving insecticide-sensitive mosquitoes. Thus, personal protection, particularly the use of bednets, should be encouraged not only at low temperatures but particularly at high temperatures when individuals avoid the use of bednets. Furthermore, control and reduction of malaria may be possible even when mosquitoes develop resistance to insecticides.
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Kull, Tuule Mall, Martin Thalfeldt et Jarek Kurnitski. « Optimal PI control parameters for accurate underfloor heating temperature control ». E3S Web of Conferences 111 (2019) : 01081. http://dx.doi.org/10.1051/e3sconf/201911101081.

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In low energy buildings, the effect of internal and solar gains on heat balance of rooms is large. As a result, the heating systems, designed assuming steady-state conditions with no heat gains, are over-dimensioned for most of the heating period. This poses a challenge for room-based control systems, especially for thermostatic valves, but also for PI controllers. Using over-dimensioned room units might result in room temperature fluctuations. For finding solutions to this problem by using simulations, correct modelling of the control system together with the room is crucial. Therefore, the aim of this research was to determine the challenges that occur while matching measured and simulated temperature profiles and test the effect of PI control parameters on the calibrated model control accuracy. The experiments were carried out for the underfloor heating system of a test building. The building was simulated in IDA-ICE software and calibration via minimising root mean square error of energy consumption in GenOpt was carried out. The PI parameters were fit by optimisation with objective to simulate the measured temperatures accurately. The effect of the optimized PI parameters was determined by comparison to IDA-ICE default parameters and parameters from Cohen-Coon method.
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Park, Young-shin, et Dongju Lee. « Optimal PID Control for Temperature Control of Chiller Equipment ». Journal of Society of Korea Industrial and Systems Engineering 45, no 3 (30 septembre 2022) : 131–38. http://dx.doi.org/10.11627/jksie.2022.45.3.131.

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Veldman, D. W. M., S. A. N. Nouwens, R. H. B. Fey, H. J. Zwart, M. M. J. van de Wal, J. D. B. J. van den Boom et H. Nijmeijer. « Optimal thermal actuation for mirror temperature control ». Computer Methods in Applied Mechanics and Engineering 398 (août 2022) : 115212. http://dx.doi.org/10.1016/j.cma.2022.115212.

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Yang, Xing Hua, Ting Rui Liu et Jing Sun. « Optimal PID Control of Heat Exchanger Temperature ». Advanced Materials Research 204-210 (février 2011) : 21–24. http://dx.doi.org/10.4028/www.scientific.net/amr.204-210.21.

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To maintain the outlet temperature at the desired set-point, a high-order outlet temperature control model is established for a shell-and–tube heat exchanger, which is based on the analysis of its heat transfer process and dynamic properties .The Optimal PID control is applied to the temerature control system on the basis of this model, and the tuning parameters of the PID controller are obtained by numerical solving of a formulated optimization problem using Matlab/Simulink. An experimental control system is set up to testify the effect of the optimal PID control. The simulation result and the practice show that the control system has a favorable control performance.
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Van Henten, E. J., et J. Bontsema. « OPEN-LOOP OPTIMAL TEMPERATURE CONTROL IN GREENHOUSES ». Acta Horticulturae, no 801 (novembre 2008) : 629–36. http://dx.doi.org/10.17660/actahortic.2008.801.72.

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SHarshenaliev, J. SH, T. P. Samochvalova et IU M. Leschenko. « Optimal control by temperature of stacks polysilicon ». IFAC Proceedings Volumes 37, no 17 (septembre 2004) : 276–79. http://dx.doi.org/10.1016/s1474-6670(17)30827-3.

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Gee, Douglas A., et W. Fred Ramirez. « Optimal temperature control for batch beer fermentation ». Biotechnology and Bioengineering 31, no 3 (20 février 1988) : 224–34. http://dx.doi.org/10.1002/bit.260310308.

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Thèses sur le sujet "Optimal temperature control"

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Trapnes, Siri Hofstad. « Optimal Temperature Control of Rooms for Minimum Energy Cost ». Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemisk prosessteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22416.

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In this thesis was a room with direct heating in the floor and room modelled. The aim has been to minimize the energy cost of the room, assuming that the future energy price and weather forecast is known. The constrained optimization problem turned out to be linear, and the solution of the problem will always be on the upper or lower bounds of the inputs or states. The idea is to store heat when the energy price is low, and use it when the energy price is high. A switching time that ensures that the model starts the heating of the system at an optimal time in order to save energy costs is thus of importance to find.The problem was solved by using the matlab function fminsearch, and by assuming constant outdoor temperature. Two scenarios were analysed; 1) where only the floor heat is used to storage of heat, and 2) where both heaters are used to heat the system. In each scenario the length and starting point of the interval where the energy price is high was varied. This thesis show that storage of heat in the floor is preferred, apart from in the case where there is no time to heat before the peak interval begins, where both heaters in the floor and room should be used. For comparison, the optimization problem was also solved by using PI controllers, where the two inputs control the temperature in the floor and room respectively. It turned out that the result of the control problem when using PI will resemble the solution of the optimal control problem when using fminsearch.A couple of switching rules was derived in order to find the optimal switching time. This thesis show that the switching rules gives a good estimate of the switching time, apart from in the case where there is no time to heat. The switching rules was used in both methods (when using PI and fminsearch) and it was found that the obtained switching time is not far from the optimal solution in any of the methods. The optimization problem when using fminsearch was tested with varying outdoor temperature. It was seen that the solution from the optimal control problem will take the disturbance into consideration if it is varied before the peak period. On the other hand, the model do not allow for a variation in the outdoor temperature after the peak period.At last, the thesis show that the switching rule handle a variation in the disturbance before the peak period as good as the optimal control problem, but when the outdoor temperature becomes too cold will the result be poor.
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Ammouri, Kevin. « Deep Reinforcement Learning for Temperature Control in Buildings and Adversarial Attacks ». Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-301052.

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Heating, Ventilation and Air Conditioning (HVAC) systems in buildings are energy consuming and traditional methods used for building control results in energy losses. The methods cannot account for non-linear dependencies in the thermal behaviour. Deep Reinforcement Learning (DRL) is a powerful method for reaching optimal control in many different control environments. DRL utilizes neural networks to approximate the optimal actions to take given that the system is in a given state. Therefore, DRL is a promising method for building control and this fact is highlighted by several studies. However, neural network polices are known to be vulnerable to adversarial attacks, which are small, indistinguishable changes to the input, which make the network choose a sub-optimal action. Two of the main approaches to attack DRL policies are: (1) the Fast Gradient Sign Method, which uses the gradients of the control agent’s network to conduct the attack; (2) to train a a DRL-agent with the goal to minimize performance of control agents. The aim of this thesis is to investigate different strategies for solving the building control problem with DRL using the building simulator IDA ICE. This thesis is also going to use the concept of adversarial machine learning by applying the attacks on the agents controlling the temperature inside the building. We first built a DRL architecture to learn how to efficiently control temperature in a building. Experiments demonstrate that exploration of the agent plays a crucial role in the training of the building control agent, and one needs to fine-tune the exploration strategy in order to achieve satisfactory performance. Finally, we tested the susceptibility of the trained DRL controllers to adversarial attacks. These tests showed, on average, that attacks trained using DRL methods have a larger impact on building control than those using FGSM, while random perturbation have almost null impact.
Ventilationssystem i byggnader är energiförbrukande och traditionella metoder som används för byggnadskontroll resulterar i förlust av energisparande. Dessa metoder kan inte ta hänsyn till icke-linjära beroenden i termisk beteenden. Djup förstärkande inlärning (DRL) är en kraftfull metod för att uppnå optimal kontroll i många kontrollmiljöer. DRL använder sig av neurala nätverk för att approximera optimala val som kan tas givet att systemet befinner sig i en viss stadie. Därför är DRL en lovande metod för byggnadskontroll och detta faktumet är markerat av flera studier. Likväl, neurala nätverk i allmänhet är kända för att vara svaga mot adversarial attacker, vilket är små ändringar i inmatningen, som gör att neurala nätverket väljer en åtgärd som är suboptimal. Syftet med denna anvhandling är att undersöka olika strategier för att lösa byggnadskontroll-problemet med DRL genom att använda sig av byggnadssimulatorn IDA ICE. Denna avhandling kommer också att använda konceptet av adversarial machine learning för att attackera agenterna som kontrollerar temperaturen i byggnaden. Det finns två olika sätt att attackera neurala nätverk: (1) Fast Gradient Sign Method, som använder gradienterna av kontrollagentens nätverk för att utföra sin attack; (2) träna en inlärningsagent med DRL med målet att minimera kontrollagenternas prestanda. Först byggde vi en DRL-arkitektur som lärde sig kontrollera temperaturen i en byggad. Experimenten visar att utforskning av agenten är en grundläggande faktor för träningen av kontrollagenten och man måste finjustera utforskningen av agenten för att nå tillfredsställande prestanda. Slutligen testade vi känsligheten av de tränade DRL-agenterna till adversarial attacker. Dessa test visade att i genomsnitt har det större påverkan på kontrollagenterna att använda DRL metoder än att använda sig av FGSM medans att attackera helt slumpmässigt har nästan ingen påverkan.
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Petersson, Victor. « Exhaust Temperature Modeling and Optimal Control of Catalytic Converter Heating ». Thesis, Linköpings universitet, Fordonssystem, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-157606.

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After reaching its light-off temperature, the catalytic aftertreatment system plays a major part in maintaining emissions at low levels for vehicles equipped with combustion engines. In this thesis, modelling of the exhaust gas temperature is investigated along with optimal control strategy for variable ignition and exhaust valve opening angles for optimal catalytic converter heating. Models for exhaust gas temperature and mass flow are presented and validated against measurement data. According to the model validation, the proposed models capture variations in ignition and exhaust valve opening angles well. Optimal control strategy for the ignition and exhaust valve opening angles to heat the catalytic converter to a predetermined temperature in the most fuel and time optimal ways are investigated by implementation of the validated models. Optimal control analysis indicates that with open wastegate, the heating time for the catalytic converter can be reduced by up to 16.4 % and the accumulated fuel to reach the desired temperature can be reduced by up to 4.6 %, compared to the case with ignition and exhaust valve opening angles fixed at nominal values. With closed wastegate the corresponding figures are 16.4 % and 4.7 %. By also including control of the variable λ-value, the heating time can be further reduced by up to 19.8 %, and the accumulated fuel consumption by up to 9.5 % with open wastegate. With closed wastegate the corresponding figures are 20.1 % decrease in heating time, and 9.8 % decrease in accumulated fuel consumption.
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Yevseienko, Oleg, Anatoliy Gapon et Dmytro Salnikov. « Searching for Optimal Control Parameters of Thermal Object Using Pulse-Width Modulation (PWM) Control with Predictive Filter ». Thesis, Lviv Polytechnic Publishing House, 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41116.

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The thesis is devote to the temperature control of objects with lumped or distributed parameters. The problems of choosing the right value of regulator’s heater power and prediction period are discussed. The major attention is paid to the process of searching the minimum value of control quantities. It is shown that the approximated second-order plane has an exact accordance with the original data. It is concluded that algorithm of PWM-control with prediction filter provides good quality control.
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Martins, Ricardo Alves. « Termorregulação e depressão metabólica em endotermos ». Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-13102009-154825/.

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A depressão metabólica em aves e mamíferos, dada a alta demanda energética destes animais, se apresenta, geralmente, como resposta às condições de escassez de alimentos e baixas temperaturas. Desta forma, este projeto busca explorar, no campo teórico, como o sistema de termorregulação poderia atuar no sentido de maximizar as reservas energéticas minimizando os gastos metabólicos (depressão metabólica). Para tanto, fazemos uso de teorias da engenharia de controle que propiciam ferramental teórico para analisar como se dariam essas minimizações, ou seja, como o sistema nervoso atuaria estabelecendo um controle (set-point hipotalâmico) que minimizasse estes gastos à medida que se desse o processo de termorregulação. Neste contexto, propomos um modelo básico de termorregulação que leva em conta temperatura corpórea, taxa metabólica e temperatura ambiente, no qual o set-point atua como um controle. Mostramos como este modelo de regulação térmica propicia, devido à sua configuração, significativa redução dos distúrbios causados por variações da temperatura ambiente. Através da teoria de controle ótimo, mostramos como o set-point hipotalâmico pode surgir como resultado da minimização de um funcional relacionado ao custo com a termorregulação. Além disso, fez-se uma análise de como a temperatura ambiente pode definir diferentes situações em termos de vantagens da depressão metabólica como mecanismo de minimização de gasto energético. Para este tipo de análise, propomos um índice de razão entre o custo metabólico constante e o obtido sob atuação do controlador durante o período em que se dá o processo. Após um período em depressão metabólica, os indivíduos devem voltar a sua condição de eutermia, e, em situações de baixa temperatura, o custo deste retorno pode suplantar as vantagens para um dado indivíduo. Assim, são analisadas as influencias da massa corpórea, onde se observa aumento do custo em decorrência da entrada em depressão metabólica por parte dos indivíduos de maior massa. Tal aumento de custo é acentuado nas situações de menor temperatura ambiente. Finalmente, uma análise relativa ao tempo para retorno à condição de eutermia é apresentada, sendo que os resultados vão ao encontro das evidencias atuais sobre a flexibilidade estratégica de muitos hibernantes.
Metabolic depression of mammals and birds, animals of high metabolic demands, normally emerges as a response to food shortage and low ambient temperature. The main goal of this research is to explore, in a theoretical perspective, how the thermoregulatory system could extend the energy reserves of these endotherms decreasing metabolic costs under those environmental conditions. To approach the problem, we propose the use of control engineering theories to analyze the way the this minimization could occur, in other words, how the nervous system would act establishing a control (hypothalamic set-point) to minimize those costs during the thermoregulatory process. In this context, we propose a basic thermoregulation model that takes into account body temperature, metabolic rate and environmental temperature, and in which the set-point acts as a control. We show how this model can significantly reduce disturbances generated by ambient temperature. Using optimal control theory, we show how the hypothalamic set-point can emerge as a result of a minimization process of a functional related to thermoregulation costs. Also, how ambient temperature can define different metabolic profiles is explored, in terms of metabolic depression and the necessary return to euthermic conditions. To quantify this analysis we propose an index, based on the ratio between a constant metabolic cost and the metabolic cost defined by the controller. After a period in metabolic depression individuals should return to their euthermic condition, and, in situations of low environmental temperature, it is shown that the cost to return can be larger than the advantages. In this way, analyzing body mass influences we observed increased metabolic depression cost in larger individuals. This cost is even higher under lower environmental temperature. Finally, the cost related to the time elapsed, until the euthermic state is reached again, is considered. These last results are in accordance with current conception about the flexibility in hibernation process.
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Andersson, Fredrik, et Hampus Andersson. « Numerical Optimal Control of Hybrid Electric Trucks : Exhaust Temperature, NOx Emission and Fuel Consumption ». Thesis, Linköpings universitet, Fordonssystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148680.

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The controls for a parallel hybrid electric truck are optimized using numerical optimal control. Trade-offs between catalyst light-off times, NOx emission and fuel consumption have been investigated for cold starts at two operating points, as well as temperature differences between conventional and hybrid powertrains during WHTC (World Harmonized Transient Cycle). A model describing the temperature dynamics of the aftertreatment system is implemented as well as temperature-based deNOx performance for both Cu-Zeolite and Fe-Zeolite catalysts. Control is performed in a piecewise linear fashion, resulting in a total of 23 states including control signals. It is shown that high temperatures can be a larger threat to catalyst performance when running the WHTC than low temperatures, for both conventional and hybrid powertrains. Furthermore, decreasing the light-off time of the catalyst does not always lead to decreased NOx emission, instead there is a trade-off between light-off time and NOx emission. It is found that there are controls that will realize decreased NOx emission for a hybrid truck during cold starts at the expense of increased fuel consumption.
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Dunbabin, Matthew D. « The influence of temperature on PZT sensors & ; actuators for active vibration control of flexible structures ». Thesis, Queensland University of Technology, 2002. https://eprints.qut.edu.au/36162/7/36162_Digitised%20Thesis-4_Redacted.pdf.

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In real operating environments, flexible structures exhibiting dynamic oscillations such as aircraft and spacecraft can experience large changes in temperature during their normal operating cycle, typically in the range -70 to 80 degrees Celsius. The use of piezoelectric actuators and sensors to control these dynamic oscillations have been widely explored at constant temperature, although only limited studies have been conducted on the effect that varying temperature has on the active control of flexible structures. The objective of this research is to study the influence of PZT sensors and actuators for vibration control of flexible structures where nonlinearities in piezoelectric and structural material properties change as the system temperatures vary significantly with time. This involved the development of a set of data based parameters that enabled the accurate modelling of a nonlinear flexible system in which its dynamics are actively controlled via the use of piezoelectric sensors and actuators. These parameters determined the design of a control scheme to actively control the system over a large range of operating temperatures, and give an optimised control performance throughout its operating regime. The work reported in this thesis describes selected methods for rapidly examining a number of the more common nonlinear properties of PZT associated with vibration control. An extensive numerical and experimental investigation is performed which shows that when used in active vibration control applications, the variations in PZT properties with temperature can ultimately affect the ability of the piezoelectric actuator and sensors to suppress vibration in flexible structures. Accurate simulation models of the lightweight piezo-actuated cantilevered structures were developed to evaluate the performance of a number of common vibration control schemes subject to significant temperature variations. This research was then extended to an innovative scaled wing-type structure subjected to temperature variations. A suitable adaptive self-tuning control scheme was developed and investigated numerically and experimentally, illustrating the benefit of adaptive control in this instance. The adaptive control technique was shown numerically and experimentally to provide improved settling times and damping ratios over equivalent fixed gain controllers for the class of structures investigated where limited control authority exists. The experimental investigation of PZT sensors and actuators has provided further understanding of the nonlinear behaviour of various light, flexible structures where temperature effects on the system dynamics and control are significant. This research has unveiled previously unreported nonlinearities and has expanded on traditional nonlinearities. These results can assist with the detailed design of applications involving PZT sensors and actuators in for example the aerospace and automotive industries.
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Kaymaz, I. Ali. « Control strategies for exothermic batch and fed-batch processes : a sub-optimal strategy is developed which combines fast response with a chosen control signal safety margin : design procedures are described and results compared with conventional control ». Thesis, University of Bradford, 1989. http://hdl.handle.net/10454/4217.

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There is a considerable scope for improving the temperature control of exothermic processes. In this thesis, a sub-optimal control strategy is developed through utilizing the dynamic, simulation tool. This scheme is built around easily obtained knowledge of the system and still retains flexibility. It can be applied to both exothermic batch and fed-batch processes. It consists of servo and regulatory modes, where a Generalized Predictive Controller (GPC) was used to provide self-tuning facilities. The methods outlined allow for limited thermal runaway whilst keeping some spare cooling capacity to ensure that operation at constraints are not violated. A special feature of the method proposed is that switching temperatures and temperature profiles can be readily found from plant trials whilst the addition rate profile Is capable of fairly straightforward computation. The work shows that It is unnecessary to demand stability for the whole of the exothermic reaction cycle, permitting a small runaway has resulted in a fast temperature response within the given safety margin. The Idea was employed for an exothermic single Irreversible reaction and also to a set of complex reactions. Both are carried out in a vessel with a heating/cooling coil. Two constraints are Imposed; (1) limited heat transfer area, and (11) a maximum allowable reaction temperature Tmax. The non-minimum phase problem can be considered as one of the difficulties in managing exothermic fed-batch process when cold reactant Is added to vessel at the maximum operating temperature. The control system coped with this within limits, a not unexpected result. In all cases, the new strategy out-performed the conventional controller and produced smoother variations in the manipulated variable. The simulation results showed that batch to batch variations and disturbances In cooling were successfully handled. GPC worked well but can be susceptible to measurement noise.
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Yin, Liangzhen. « Intelligent control for performance optimization of proton exchange membrane fuel cell system ». Electronic Thesis or Diss., Bourgogne Franche-Comté, 2023. http://www.theses.fr/2023UBFCA013.

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Le système de pile à combustible à membrane échangeuse de protons (PEMFC) a été considéré comme la nouvelle technologie de production d'énergie, car il présente l'avantage d'une densité de puissance élevée, d'une absence d'émissions, d'un rendement élevé et d'un démarrage rapide. C'est pourquoi cette thèse est consacrée à la recherche sur l'intégration du système, le contrôle des paramètres du système et l'optimisation des performances du système pour les systèmes PEMFC à cathode ouverte et à cathode fermée. Pour les systèmes PEMFC à cathode ouverte, la température de la pile est le facteur clé affectant la performance de sortie du système. Afin d'améliorer les performances de suivi dynamique de la température dans des conditions de changement de charge, un contrôle adaptatif inverse et une prédiction grise basés sur un contrôle adaptatif sans modèle sont proposés pour un contrôle optimal de la température du système. En outre, afin d'améliorer l'efficacité du système, une stratégie de contrôle de l'efficacité maximale basée sur l'optimisation de l'efficacité maximale et la commande prédictive généralisée par contrainte est proposée dans cette thèse. Pour le système PEMFC à cathode fermée, compte tenu de la non-linéarité existante et du fort couplage entre les paramètres de fonctionnement tels que la température de la pile et le taux d'excès d'oxygène (OER), une stratégie de contrôle multivariable à double boucle basée sur un contrôle adaptatif en mode glissant sans modèle MIMO est proposée pour la régulation de la température de la pile et du débit d'air du système PEMFC à cathode fermée. En outre, un banc d'essai de système PEMFC à cathode ouverte de 300 W et un banc d'essai de système PEMFC à cathode fermée de 5 kW sont établis. Toutes les stratégies de contrôle et d'optimisation des performances sont vérifiées sur le banc d'essai des systèmes PEMFC à cathode ouverte et à cathode fermée
Proton exchange membrane fuel cell (PEMFC) system has been considered as the new power generation technology as it has the advantage of high power density, zero emission, high efficiency, and fast start-up characteristics. Therefore, this thesis is devoted to researching system integration, system parameter trcking control, and system performance optimization for open-cathode and closed-cathode PEMFC systems. For open-cathode PEMFC system, the stack temperature is the key factor sffecting the output performance of the system. In order to improve the dynamic temperature tracking performance under load changing conditions, adaptive inverse control and grey prediction based model free adaptive control is proposed for optimal temperature control of system. Further, in order to enhance the system efficiency of system, a maximum efficiency control strategy based on maximum efficiency optimization and constraint generalized predictive control is proposed in this thesis. For closed-cathode PEMFC system, considering the existed nonlinearity and strong coupling between operating parameters such as stack temperature and oxygen excess ratio (OER), a dual loop multivariable control strategy based on MIMO model free adaptive sliding mode control is proposed for stack temperature and air flow rate regulation of closed-cathode PEMFC system. Moreover, a 300 W open-cathode PEMFC system test bench and a 5-kW closed-cathode PEMFC system tests bench are established. All the control strategies and the performance optimization strategies are verified on the established test bench of open-cathode and closed-cathode PEMFC systems
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Costa, Filho Pedro Turibe. « Plataforma de Testes de Algoritmos de Controle para Sistemas em Tempo Real ». Universidade Federal do Maranhão, 2006. http://tedebc.ufma.br:8080/jspui/handle/tede/446.

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Made available in DSpace on 2016-08-17T14:53:12Z (GMT). No. of bitstreams: 1 Pedro Turibe.pdf: 1407215 bytes, checksum: 1301d5c29a7bdde34bd0b2385be26a03 (MD5) Previous issue date: 2006-10-30
The conception, design and synthesis of a platform to evaluate the performance of the in real time control algorithms is the main focuses of this Master Thesis. For conception purpose, the platform is classi¯ed in structural and functional parts, the structural one is composed of the hardware that are sensors, actuators, controllers and related devices. The functional part is formed by algorithms to manager the platform resources and real time control strategies. The platform is dedicated to the speed control of a direct current motor and the temperature control of an electric furnace. These plants are used to develop methods for real time control, parameter estimation and controller tuning. The parameter estima- tion of the motor and furnace is performed in the platform, the obtained models are used to design the PID controller optimal gains.
Apresenta-se uma metodologia para o projeto de uma plataforma para avaliar o desempenho de algoritmos de controle em tempo real. O sistema é organizado em partes estrutural e funcional; a estrutural é constituída pelos elementos de hardware que são as plantas, sensores, atuadores e controladores; a parte funcional é constituída pelos algoritmos para o gerenciamento dos recursos da plataforma e para controle de sistemas dinâmicos. A plataforma é dedicada ao controle de velocidade de um motor de corrente continua e controle de temperatura de um forno elétrico, estas plantas são utilizadas para o desenvolvimento de métodos e verificação de aplicações de controle em tempo real, estimação de parâmetros e sintonia de ganhos dos controladores. A plataforma é utilizada para o levantamento dos parâmetros do motor e forno. Os modelos das plantas são utilizados para o projeto de controladores do tipo PID que são sintonizados por métodos de otimização.
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Livres sur le sujet "Optimal temperature control"

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L, Tuma Margaret, et United States. National Aeronautics and Space Administration., dir. Fabry-Perot fiber-optic temperature sensor system. [Washington, D.C : National Aeronautics and Space Administration, 1997.

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Michael, Bremer, et SpringerLink (Online service), dir. Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures. Berlin, Heidelberg : Springer-Verlag Berlin Heidelberg, 2010.

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Canfield, Donald Eugene. What Is It about Planet Earth ? Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691145020.003.0001.

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This chapter begins by highlighting the three basic ingredients for life: energy, the chemical components that make up cells, and water. It then shows that the availability of each of these is linked by special properties of planet Earth. It concludes that Earth is a pretty terrific place for life. It sits comfortably within the habitable zone of the Sun. In addition, its active tectonics both control the temperature of the surface environment, providing a continuous supply of liquid water, and recycle the basic components required to fuel abundant life. The same tectonics may have also provided optimal conditions for the earliest biosphere.
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Nguyen, Kim-Phuong, et Chris D. Glover. Anesthetic Considerations for Scoliosis Repair. Sous la direction de Erin S. Williams, Olutoyin A. Olutoye, Catherine P. Seipel et Titilopemi A. O. Aina. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190678333.003.0032.

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Scoliosis is an anatomical deformity caused by a lateral and rotational shift in the thoracolumbar spine. Surgical correction involves wide exposure of the spine for placement of stabilizing rods and can result in significant complications from excessive blood loss and neurologic impairments. These procedures require vigilance to acid-base status, hemodynamic fluctuations, coagulation, temperature maintenance, and neurologic monitoring from anesthesiologists. Other major anesthetic considerations discussed include maintaining the integrity of perfusion to the spinal cord, positioning concerns, optimal technique for neuromonitoring, and pain control in the perioperative period. This chapter presents a case study of a 14-year-old girl with adolescent idiopathic scoliosis who presents for posterior spinal instrumentation and fusion from T4-L4 with autologous bone graft.
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Rees, David. Insects of Stored Grain. CSIRO Publishing, 2007. http://dx.doi.org/10.1071/9780643094673.

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A pocket reference that allows the non-specialist to identify major insect and arachnid pests found in stored cereal grains, grain products and grain legumes. It describes most storage pests found worldwide and provides concise information on the biology, distribution, damage and economic importance of each species. Each entry contains at least one colour photograph. The notes for each species tell the nature of the pest or beneficial and the commodity affected; temperature and humidity conditions at which the species can survive; optimum conditions at which eggs take the shortest time to develop into adults; and maximum population growth rate per month. This new edition has twice as many species in it and more detail on distribution, host range and pest status than the previous edition. Short introductory sections on insect biology, principles of control and concepts of pest status evaluation have also been added.
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Bremer, Michael, et Albert Greve. Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures. Springer, 2012.

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Chapitres de livres sur le sujet "Optimal temperature control"

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Hinsberger, H., S. Miesbach et H. J. Pesch. « Optimal Temperature Control of Semibatch Polymerization Reactors ». Dans Scientific Computing in Chemical Engineering, 75–83. Berlin, Heidelberg : Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-80149-5_9.

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Suzuki, Seiichi, Akira Anju et Mutsuto Kawahara. « Parameter Identification and Optimal Control of Underground Temperature ». Dans Computational Methods in Water Resources X, 807–14. Dordrecht : Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-010-9204-3_98.

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Herrero, H., et F. Pla. « Optimal Control of Buoyant Flows with Temperature-Dependent Viscosity ». Dans Progress in Industrial Mathematics at ECMI 2008, 881–86. Berlin, Heidelberg : Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12110-4_141.

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Liu, Derong, Qinglai Wei, Ding Wang, Xiong Yang et Hongliang Li. « Data-Based Neuro-Optimal Temperature Control of Water Gas Shift Reaction ». Dans Adaptive Dynamic Programming with Applications in Optimal Control, 571–90. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-50815-3_14.

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Cui, Guimei, et Guibao Ding. « Research on the Optimal Control of Tube Billet Temperature for Rotary Reheating Furnace ». Dans Advanced Electrical and Electronics Engineering, 471–77. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19712-3_60.

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Singh, Sanjay Kumar, D. Boolchandani, S. G. Modani et Nitish Katal. « Optimal Tuning of PID Controller for Centrifugal Temperature Control System in Sugar Industry Using Genetic Algorithm ». Dans Advances in Intelligent Systems and Computing, 183–91. Singapore : Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-0451-3_18.

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Geldhof, Joost J., Agata M. Malinowska, Gijs J. L. Wuite, Erwin J. G. Peterman et Iddo Heller. « Temperature Quantification and Temperature Control in Optical Tweezers ». Dans Optical Tweezers, 123–40. New York, NY : Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2229-2_7.

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Yu, H. P., Y. K. Sui, J. Wang, X. L. Dai et G. P. An. « Optimal Control of Temperature Gradient in a Large Size Magnetic Czochralski Silicon Crystal Growth by Response Surface Methodology ». Dans Computational Methods in Engineering & ; Science, 330. Berlin, Heidelberg : Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/978-3-540-48260-4_176.

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Xu, Zhe, Xulong Che, Bishi He, Yaguang Kong et Anke Xue. « Research on Temperature Optimal Control for the Continuous Casting Billet in Induction Heating Process Based on ARX Model ». Dans Lecture Notes in Electrical Engineering, 777–86. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-38460-8_86.

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Zhang, Yihan, Zhenfei Xiao et Jinna Li. « Optimal Control for Cracking Outlet Temperature (COT) of SC-1 Ethylene Cracking Furnace by Off-Policy Q-Learning Approach ». Dans Communications in Computer and Information Science, 342–55. Singapore : Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-33-4932-2_25.

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Actes de conférences sur le sujet "Optimal temperature control"

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Wyman, Douglas R., Carrie-Lynne Swift, Rosemarie A. Siwek et Brian C. Wilson. « Optimal temperature control in laser hyperthermia ». Dans OE/LASE '90, 14-19 Jan., Los Angeles, CA, sous la direction de Abraham Katzir. SPIE, 1990. http://dx.doi.org/10.1117/12.17601.

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Astashova, I. V., A. V. Filinovskiy et D. A. Lashin. « On optimal temperature control in hothouses ». Dans INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2016). Author(s), 2017. http://dx.doi.org/10.1063/1.4992311.

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Yang, Zhichao, Bo Sun, Fan Li et Liang Zhang. « A Temperature Optimal Control Method of Temperature Control System Considering Thermal Inertia ». Dans 2019 Chinese Control Conference (CCC). IEEE, 2019. http://dx.doi.org/10.23919/chicc.2019.8865163.

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Riascos, Luis A. M., et David D. Pereira. « Optimal temperature control in PEM fuel cells ». Dans IECON 2009 - 35th Annual Conference of IEEE Industrial Electronics (IECON). IEEE, 2009. http://dx.doi.org/10.1109/iecon.2009.5415416.

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Yadav, Vivek, Radhakant Padhi et S. N. Balakrishnan. « Robust/optimal temperature profile control using neural networks ». Dans 2006 IEEE Conference on Computer Aided Control System Design, 2006 IEEE International Conference on Control Applications, 2006 IEEE International Symposium on Intelligent Control. IEEE, 2006. http://dx.doi.org/10.1109/cacsd-cca-isic.2006.4777145.

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Jiliang, Shang, Yu Wei et Gao Dexin. « Study of Compound Optimal Control for Beer Saccharification Temperature ». Dans 2007 Chinese Control Conference. IEEE, 2006. http://dx.doi.org/10.1109/chicc.2006.4346790.

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Zenghuan, Liu, Wang Lizhen et He Guangxiang. « Study on Optimal Control of Furnace Temperature Uniformity ». Dans 2011 International Conference on Intelligent Computation Technology and Automation (ICICTA). IEEE, 2011. http://dx.doi.org/10.1109/icicta.2011.141.

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Yadav, Vivek, Radhakant Padhi et S. Balakrishnan. « Robust/Optimal Temperature Profile Control Using Neural Networks ». Dans 2006 IEEE International Conference on Control Applications. IEEE, 2006. http://dx.doi.org/10.1109/cca.2006.286115.

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Zhou, Su, Xuelei Zhi et Linjiong Yu. « Temperature Control of PEMFC Based on Optimal Power Consumption ». Dans 2019 Chinese Control Conference (CCC). IEEE, 2019. http://dx.doi.org/10.23919/chicc.2019.8865220.

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Dongsuk Kum, Huei Peng et Norman K. Bucknor. « Optimal catalyst temperature management of Plug-in Hybrid Electric Vehicles ». Dans 2011 American Control Conference. IEEE, 2011. http://dx.doi.org/10.1109/acc.2011.5991499.

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Rapports d'organisations sur le sujet "Optimal temperature control"

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Meza, J. C., et T. D. Plantenga. Optimal control of a CVD reactor for prescribed temperature behavior. Office of Scientific and Technical Information (OSTI), avril 1995. http://dx.doi.org/10.2172/61183.

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Martinez, Melissa. Visual Patching and Imaging Chambers. ConductScience, juillet 2022. http://dx.doi.org/10.55157/cs20220507.

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Specimens obtained from brain slicing experiments, cell research, and skin studies are sensitive to temperature variations, humidity, and air quality. Proper temperature control is crucial to prevent cell distortion and necrosis, ensuring accurate observations and data collection. A visual patching and imaging chamber is introduced as a vital tool for maintaining optimal specimen temperature in behavioral, neuroimaging, and electrophysiological studies. The chamber features an aluminum heat exchanger plate with precise temperature control, gas inlet, and perfusate tubes. It's used in rodent research for preserving tissue viability and collecting accurate data in various experiments.
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Lieth, J. Heiner, Michael Raviv et David W. Burger. Effects of root zone temperature, oxygen concentration, and moisture content on actual vs. potential growth of greenhouse crops. United States Department of Agriculture, janvier 2006. http://dx.doi.org/10.32747/2006.7586547.bard.

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Soilless crop production in protected cultivation requires optimization of many environmental and plant variables. Variables of the root zone (rhizosphere) have always been difficult to characterize but have been studied extensively. In soilless production the opportunity exists to optimize these variables in relation to crop production. The project objectives were to model the relationship between biomass production and the rhizosphere variables: temperature, dissolved oxygen concentration and water availability by characterizing potential growth and how this translates to actual growth. As part of this we sought to improve of our understanding of root growth and rhizosphere processes by generating data on the effect of rhizosphere water status, temperature and dissolved oxygen on root growth, modeling potential and actual growth and by developing and calibrating models for various physical and chemical properties in soilless production systems. In particular we sought to use calorimetry to identify potential growth of the plants in relation to these rhizosphere variables. While we did experimental work on various crops, our main model system for the mathematical modeling work was greenhouse cut-flower rose production in soil-less cultivation. In support of this, our objective was the development of a Rose crop model. Specific to this project we sought to create submodels for the rhizosphere processes, integrate these into the rose crop simulation model which we had begun developing prior to the start of this project. We also sought to verify and validate any such models and where feasible create tools that growers could be used for production management. We made significant progress with regard to the use of microcalorimetry. At both locations (Israel and US) we demonstrated that specific growth rate for root and flower stem biomass production were sensitive to dissolved oxygen. Our work also identified that it is possible to identify optimal potential growth scenarios and that for greenhouse-grown rose the optimal root zone temperature for potential growth is around 17 C (substantially lower than is common in commercial greenhouses) while flower production growth potential was indifferent to a range as wide as 17-26C in the root zone. We had several set-backs that highlighted to us the fact that work needs to be done to identify when microcalorimetric research relates to instantaneous plant responses to the environment and when it relates to plant acclimation. One outcome of this research has been our determination that irrigation technology in soilless production systems needs to explicitly include optimization of oxygen in the root zone. Simply structuring the root zone to be “well aerated” is not the most optimal approach, but rather a minimum level. Our future work will focus on implementing direct control over dissolved oxygen in the root zone of soilless production systems.
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Firon, Nurit, Prem Chourey, Etan Pressman, Allen Hartwell et Kenneth J. Boote. Molecular Identification and Characterization of Heat-Stress-Responsive Microgametogenesis Genes in Tomato and Sorghum - A Feasibility Study. United States Department of Agriculture, octobre 2007. http://dx.doi.org/10.32747/2007.7591741.bard.

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Exposure to higher than optimal temperatures - heat-stress (HS) - is becoming increasingly common to all crop plants worldwide. Heat stress coinciding with microgametogenesis, especially during the post-meiotic phase that is marked by starch biosynthesis, is often associated with starch-deficient pollen and male sterility and ultimately, greatly reduced crop yields. The molecular basis for the high sensitivity of developing pollen grains, on one hand, and factors involved in pollen heat-tolerance, on the other, is poorly understood. The long-term goal of this project is to provide a better understanding of the genes that control pollen quality under heat-stress conditions. The specific objectives of this project were: (1) Determination of the threshold heat stress temperature(s) that affects tomato and sorghum pollen quality whether: a) Chronic mild heat stress conditions (CMHS), or b) Acute heat stress (AHS). (2) Isolation of heat-responsive, microgametogenesis-specific sequences. During our one-year feasibility project, we have accomplished the proposed objectives as follows: Objectrive 1: We have determined the threshold HS conditions in tomato and sorghum. This was essential for achieving the 2nd objective, since our accumulated experience (both Israeli and US labs) indicate that when temperature is raised too high above "threshold HS levels" it may cause massive death of the developing pollen grains. Above-threshold conditions have additional major disadvantages including the "noise" caused by induced expression of genes involved in cell death and masking of the differences between heatsensitive and heat-tolerant pollen grains. Two different types of HS conditions were determined: a) Season-long CMHS conditions: 32/26°C day/night temperatures confirmed in tomato and 36/26°C day maximum/night minimum temperatures in sorghum. b) Short-term AHS: In tomato, 2 hour exposure to 42-45°C (at 7 to 3 days before anthesis) followed by transfer to 28/22±2oC day/night temperatures until flower opening and pollen maturation, caused 50% reduced germinating pollen in the heat-sensitive 3017 cv.. In sorghum, 36/26°C day/night temperatures 10 to 5 days prior to panicle emergence, occurring at 35 days after sowing (DAS) in cv. DeKalb28E, produced starch-deficient and sterile pollen. Objective 2: We have established protocols for the high throughput transcriptomic approach, cDNA-AFLP, for identifying and isolating genes exhibiting differential expression in developing microspores exposed to either ambient or HS conditions and created a databank of HS-responsivemicrogametogenesis-expressed genes. A subset of differentially displayed Transcript-Derived Fragments (TDFs) that were cloned and sequenced (35 & 23 TDFs in tomato and sorghum, respectively) show close sequence similarities with metabolic genes, genes involved in regulation of carbohydrate metabolism, genes implicated in thermotolerance (heat shock proteins), genes involved in long chain fatty acids elongation, genes involved in proteolysis, in oxidation-reduction, vesicle-mediated transport, cell division and transcription factors. T-DNA-tagged Arabidopsis mutants for part of these genes were obtained to be used for their functional analysis. These studies are planned for a continuation project. Following functional analyses of these genes under HS – a valuable resource of genes, engaged in the HS-response of developing pollen grains, that could be modulated for the improvement of pollen quality under HS in both dicots and monocots and/or used to look for natural variability of such genes for selecting heat-tolerant germplasm - is expected.
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Benedict, Katherine, Michael Moosmuller, Kyle Gorkowski et Manvendra Dubey. Improved temperature control for measuring the humidity dependence of aerosol optical properties. Office of Scientific and Technical Information (OSTI), août 2021. http://dx.doi.org/10.2172/1813816.

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Yahav, Shlomo, John Brake et Orna Halevy. Pre-natal Epigenetic Adaptation to Improve Thermotolerance Acquisition and Performance of Fast-growing Meat-type Chickens. United States Department of Agriculture, septembre 2009. http://dx.doi.org/10.32747/2009.7592120.bard.

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: The necessity to improve broiler thermotolerance and performance led to the following hypothesis: (a) thethermoregulatory-response threshold for heat production can be altered by thermal manipulation (TM) during incubation so as to improve the acquisition of thermotolerance in the post-hatch broiler;and (b) TM during embryogenesis will improve myoblast proliferation during the embryonic and post-hatch periods with subsequent enhanced muscle growth and meat production. The original objectives of this study were as follow: 1. to assess the timing, temperature, duration, and turning frequency required for optimal TM during embryogenesis; 2. to evaluate the effect of TM during embryogenesis on thermoregulation (heat production and heat dissipation) during four phases: (1) embryogenesis, (2) at hatch, (3) during growth, and (4) during heat challenge near marketing age; 3. to investigate the stimulatory effect of thermotolerance on hormones that regulate thermogenesis and stress (T₄, T₃, corticosterone, glucagon); 4. to determine the effect of TM on performance (BW gain, feed intake, feed efficiency, carcass yield, breast muscle yield) of broiler chickens; and 5. to study the effect of TM during embryogenesis on skeletal muscle growth, including myoblast proliferation and fiber development, in the embryo and post-hatch chicks.This study has achieved all the original objectives. Only the plasma glucagon concentration (objective 3) was not measured as a result of technical obstacles. Background to the topic: Rapid growth rate has presented broiler chickens with seriousdifficulties when called upon to efficiently thermoregulate in hot environmental conditions. Being homeotherms, birds are able to maintain their body temperature (Tb) within a narrow range. An increase in Tb above the regulated range, as a result of exposure to environmental conditions and/or excessive metabolic heat production that often characterize broiler chickens, may lead to a potentially lethal cascade of irreversible thermoregulatory events. Exposure to temperature fluctuations during the perinatal period has been shown to lead to epigenetic temperature adaptation. The mechanism for this adaptation was based on the assumption that environmental factors, especially ambient temperature, have a strong influence on the determination of the “set-point” for physiological control systems during “critical developmental phases.” In order to sustain or even improve broiler performance, TM during the period of embryogenesis when satellite cell population normally expand should increase absolute pectoralis muscle weight in broilers post-hatch. Major conclusions: Intermittent TM (39.5°C for 12 h/day) during embryogenesis when the thyroid and adrenal axis was developing and maturing (E7 to E16 inclusive) had a long lasting thermoregulatory effect that improved thermotolerance of broiler chickens exposed to acute thermal stress at market age by lowering their functional Tb set point, thus lowering metabolic rate at hatch, improving sensible heat loss, and significantly decreasing the level of stress. Increased machine ventilation rate was required during TM so as to supply the oxygen required for the periods of increased embryonic development. Enhancing embryonic development was found to be accomplished by a combination of pre-incubation heating of embryos for 12 h at 30°C, followed by increasing incubation temperature to 38°C during the first 3 days of incubation. It was further facilitated by increasing turning frequency of the eggs to 48 or 96 times daily. TM during critical phases of muscle development in the late-term chick embryo (E16 to E18) for 3 or 6 hours (39.5°C) had an immediate stimulatory effect on myoblast proliferation that lasted for up to two weeks post-hatch; this was followed by increased hypertrophy at later ages. The various incubation temperatures and TM durations focused on the fine-tuning of muscle development and growth processes during late-term embryogenesis as well as in post-hatch chickens.
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Moosmuller, Michael, Kyle Gorkowski, Katherine Benedict et Manvendra Dubey. Improved Temperature Control for Measuring the Humidity Dependence of Aerosol Optical Properties [Slides]. Office of Scientific and Technical Information (OSTI), juillet 2021. http://dx.doi.org/10.2172/1811850.

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Olsen. PR-179-07200-R01 Evaluation of NOx Sensors for Control of Aftertreatment Devices. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), juin 2008. http://dx.doi.org/10.55274/r0010985.

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Emissions reduction through exhaust aftertreatment is becoming more common. It is likely to play an important role in meeting new emissions regulations in the future. Currently, the predominate aftertreatment technology for NOX reduction in lean burn natural gas engines appears to be selective catalytic reduction (SCR). In SCR, a reducing agent is injected into the exhaust upstream of a catalyst. Supplying the optimal quantity of reagent is critical to effective application of SCR. If too little reagent is supplied then the NOx reduction efficiency may be too low. If too much reagent is provided then the ammonia slip may be too high. Control of reagent injection is an area where improvements could be made. In many current SCR systems, the rate of reagent injection is determined by engine loading. The relationship between engine loading and engine out NOX emission is determined during SCR system commissioning, and assumed to remain constant. Ideally, NOX emissions would be measured and used as feedback to the SCR system. It may also be advantageous to employ transient reagent injection based on time dependent variations in NOX mass flow in the exhaust. This would be possible with a fast response NOx sensor. Close loop engine control is an area of increasing importance. As regulatory emissions levels are reduced, compliance margins generally decrease. Precise control of air/fuel ratio and ignition timing become more critical. Cylinder-to-cylinder control of air/fuel ratio, ignition timing, and IMEP are also important. Advanced sensors are an enabling technology for more precise engine control. Ion sensing is an example of a technology that potentially can improve cylinder balancing and ignition timing. Cylinder-to-cylinder air/fuel ratio can be accomplished in several different ways. One approach would be to install individual sensors in the exhaust manifold, one for each cylinder. Ceramic based sensors (O2 and NOx) may be reliable enough at exhaust port temperatures. They are typically used in the exhaust of 4-stroke cycle engines, which have higher exhaust temperatures than 2-stroke cycle engines. Ceramic based NOx sensors have been under development for use, primarily, in Lean NOx Traps (LNTs). This technology is expected to be used on over-the-road Diesel truck engines in 2010. Therefore, the research effort has momentum. This provides an opportunity to capitalize on the efforts of another industry. In this project a NOx sensor will be evaluated using the SCR slipstream system on the GMV-4TF. The basic tasks are: 1. Identify commercial NOx sensors and procure most promising sensor 2. Design and modification of SCR slipstream system to accept sensors 3. Installation of sensors, sensor electronics, and data logging hardware and software 4. Sensor evaluation during SCR slipstream testing.
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Yahav, Shlomo, John McMurtry et Isaac Plavnik. Thermotolerance Acquisition in Broiler Chickens by Temperature Conditioning Early in Life. United States Department of Agriculture, 1998. http://dx.doi.org/10.32747/1998.7580676.bard.

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The research on thermotolerance acquisition in broiler chickens by temperature conditioning early in life was focused on the following objectives: a. To determine the optimal timing and temperature for inducing the thermotolerance, conditioning processes and to define its duration during the first week of life in the broiler chick. b. To investigate the response of skeletal muscle tissue and the gastrointestinal tract to thermal conditioning. This objective was added during the research, to understand the mechanisms related to compensatory growth. c. To evaluate the effect of early thermo conditioning on thermoregulation (heat production and heat dissipation) during 3 phases: (1) conditioning, (2) compensatory growth, (3) heat challenge. d. To investigate how induction of improved thermotolerance impacts on metabolic fuel and the hormones regulating growth and metabolism. Recent decades have seen significant development in the genetic selection of the meat-type fowl (i.e., broiler chickens); leading to rapid growth and increased feed efficiency, providing the poultry industry with heavy chickens in relatively short growth periods. Such development necessitates parallel increases in the size of visceral systems such as the cardiovascular and the respiratory ones. However, inferior development of such major systems has led to a relatively low capability to balance energy expenditure under extreme conditions. Thus, acute exposure of chickens to extreme conditions (i.e., heat spells) has resulted in major economic losses. Birds are homeotherms, and as such, they are able to maintain their body temperature within a narrow range. To sustain thermal tolerance and avoid the deleterious consequences of thermal stresses, a direct response is elicited: the rapid thermal shock response - thermal conditioning. This technique of temperature conditioning takes advantage of the immaturity of the temperature regulation mechanism in young chicks during their first week of life. Development of this mechanism involves sympathetic neural activity, integration of thermal infom1ation in the hypothalamus, and buildup of the body-to-brain temperature difference, so that the potential for thermotolerance can be incorporated into the developing thermoregulation mechanisms. Thermal conditioning is a unique management tool, which most likely involves hypothalamic them1oregulatory threshold changes that enable chickens, within certain limits, to cope with acute exposure to unexpected hot spells. Short-tem1 exposure to heat stress during the first week of life (37.5+1°C; 70-80% rh; for 24 h at 3 days of age) resulted in growth retardation followed immediately by compensatory growth" which resulted in complete compensation for the loss of weight gain, so that the conditioned chickens achieved higher body weight than that of the controls at 42 days of age. The compensatory growth was partially explained by its dramatic positive effect on the proliferation of muscle satellite cells which are necessary for further muscle hypertrophy. By its significant effect of the morphology and functioning of the gastrointestinal tract during and after using thermal conditioning. The significant effect of thermal conditioning on the chicken thermoregulation was found to be associated with a reduction in heat production and evaporative heat loss, and with an increase in sensible heat loss. It was further accompanied by changes in hormones regulating growth and metabolism These physiological responses may result from possible alterations in PO/AH gene expression patterns (14-3-3e), suggesting a more efficient mechanism to cope with heat stress. Understanding the physiological mechanisms behind thermal conditioning step us forward to elucidate the molecular mechanism behind the PO/AH response, and response of other major organs. The thermal conditioning technique is used now in many countries including Israel, South Korea, Australia, France" Ecuador, China and some places in the USA. The improvement in growth perfom1ance (50-190 g/chicken) and thermotolerance as a result of postnatal thermal conditioning, may initiate a dramatic improvement in the economy of broiler's production.
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Huang, Cihang, Yen-Fang Su et Na Lu. Self-Healing Cementitious Composites (SHCC) with Ultrahigh Ductility for Pavement and Bridge Construction. Purdue University, 2021. http://dx.doi.org/10.5703/1288284317403.

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Cracks and their formations in concrete structures have been a common and long-lived problem, mainly due to the intrinsic brittleness of the concrete. Concrete structures, such as rigid pavement and bridge decks, are prone to deformations and deteriorations caused by shrinkage, temperature fluctuation, and traffic load, which can affect their service life. Rehabilitation of concrete structures is expensive and challenging—not only from maintenance viewpoints but also because they cannot be used for services during maintenance. It is critical to significantly improve the ductility of concrete to overcome such issues and to enable better infrastructure quality. To this end, the self-healing cementitious composites (SHCC) investigated in this work could be a promising solution to the aforementioned problems. In this project, the team has designed a series of cementitious composites to investigate their mechanical performances and self-healing abilities. Firstly, various types of fibers were investigated for improving ductility of the designed SHCC. To enhance the self-healing of SHCC, we proposed and examined that the combination of the internal curing method with SHCC mixture design can further improve self-healing performance. Three types of internal curing agents were used on the SHCC mixture design, and their self-healing efficiency was evaluated by multiple destructive and non-destructive tests. Results indicated a significant improvement in the self-healing capacity with the incorporation of internal curing agents such as zeolite and lightweight aggregate. To control the fiber distribution and workability of the SHCC, the mix design was further adjusted by controlling rheology using different types of viscosity modifiers. The team also explored the feasibility of the incorporation of colloidal nano-silica into the mix design of SHCC. Results suggest that optimum amounts of nano-silica have positive influence on self-healing efficiency and mechanical properties of the SHCC. Better hydration was also achieved by adding the nano-silica. The bonding strength of the SHCC with conventional concrete was also improved. At last, a standardized mixing procedure for the large scale SHCC was drafted and proposed.
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