Literatura académica sobre el tema "Collective heating"
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Artículos de revistas sobre el tema "Collective heating"
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Cabezas-Rivière, Enzo, Thomas Recht, Aline Barlet, Maxime Robillart, Mathieu Bouville y Patrick Sebastian. "Towards sustainable energy consumption for occupants of buildings with collective heating systems". Journal of Physics: Conference Series 2600, n.º 9 (1 de noviembre de 2023): 092019. http://dx.doi.org/10.1088/1742-6596/2600/9/092019.
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Abstract Global warming is forcing us all to reduce our fossil energy consumption. A quantitative survey of people using collective heating in France was conducted to determine whether collective heating hinders energy savings and limits their thermal comfort. The study shows that the existing environment (e.g., heating control devices, access to heating bills) is not suitable for the occupants. Furthermore, the results point out that behaviour is not considered, by occupants, as one of the main energy saving vectors. This is partly due to heating control devices that can be inconvenient to use and thus do not maximize their thermal comfort. Indeed, there is a large difference between the temperature residents want, and the one they get. Our study population reported that rooms are colder than people wish. To achieve sustainable energy savings, efforts should be made to better take into account their comfort while making the technical system more suitable to the occupants, for example, by improving access to and understanding of bills and replacing the current manual control valves with programmable and remotely controllable ones.
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CHIEN, L. H., A. SERGEEV, N. VAGIDOV, V. MITIN y S. BIRNER. "ELECTRON HEATING IN QUANTUM-DOT STRUCTURES WITH COLLECTIVE POTENTIAL BARRIERS". International Journal of High Speed Electronics and Systems 20, n.º 01 (marzo de 2011): 143–52. http://dx.doi.org/10.1142/s0129156411006477.
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Here we report our research on quantum-dot structures with collective barriers surrounding groups of quantum dots (planes, clusters etc) and preventing photoelectron capture. Employing Monte-Carlo simulations, we investigate photoelectron kinetics and calculate the photoelectron lifetime as a function of geometrical parameters of the structures, dot occupation, and electric field. Results of our simulations demonstrate that the capture processes are substantially suppressed by the potential barriers and enhanced in strong electric fields. Detailed analysis shows that the effects of the electric field can be explained by electron heating, i.e. field effects become significant, when the shift of the electron temperature due to electron heating reaches the barrier height. Optimized photoelectron kinetics in quantum-dot structures with collective barriers allows for significant improvements in the photoconductive gain, detectivity, and responsivity of photodetectors based on these structures.
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Knatko M.V. y Lapushkin M.N. "Collective processes in thermal ionization on the surface of NaAu-=SUB=-x-=/SUB=- intermetallic compound". Technical Physics 92, n.º 9 (2022): 1237. http://dx.doi.org/10.21883/tp.2022.09.54689.87-22.
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A mechanism is proposed for the decomposition of molecular clusters of diethylamine (C2H5)2NH on the surface of the NaAux intermetallic compound with the formation of decomposition products desorbed from the surface, including in the form of ions with m/z from 58 to 197, during heating of the intermetallic compound at a rate of 20 K/s. Exposure of the NaAux surface at a temperature of 320 K in diethylamine vapor leads to the formation of molecular clusters on it. Rapid heating of NaAux at a rate of 20 K/s leads to the decay of clusters, desorption, and ionization of the decay products due to the redistribution of internal energy over the degrees of freedom of the cluster. The study of thermal ionization processes during heating of NaAux at a rate of 20 K/s in the temperature range from 600 to 1000 K made it possible to establish that the surface stoichiometry during heating is quasi-stationary, dehydrogenation and ionization of individual diethylamine molecules occur under equilibrium conditions, while for compounds formed in the process of cluster decay, the conditions are not equilibrium. Keywords: thermal ionization, diethylamine, intermetallics, sodium, gold.
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Vlasov, V. G., V. V. Klimenko, G. K. Matafonov y A. V. Tashchilin. "Collective heating and radiation dynamics of the auroral ionospheric F2-region". Journal of Atmospheric and Terrestrial Physics 54, n.º 7-8 (julio de 1992): 995–1005. http://dx.doi.org/10.1016/0021-9169(92)90066-t.
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Ali, Emad, Abdelhamid Ajbar y Bilal Lamrani. "Numerical Investigation of Thermal Energy Storage Systems for Collective Heating of Buildings". Buildings 14, n.º 1 (6 de enero de 2024): 141. http://dx.doi.org/10.3390/buildings14010141.
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This study aims to investigate and identify the most effective thermal energy storage (TES) system configuration for the collective heating of buildings. It compares three TES technologies, i.e., sensible, latent, and cascade latent shell and tube storage, and examines their respective performances. A fast and accurate lumped thermal dynamic model to efficiently simulate TES system performances under different operation conditions is developed. The validation of this model’s accuracy is achieved by aligning numerical findings with data from prior experimental studies. Key findings indicated that the latent and cascade latent shell and tube storage systems demonstrate superior thermal energy storage capacities compared to the sensible configuration. Using a single-phase change material (PCM) tank increases the duration of constant thermal power storage by about 50%, and using a cascade PCM tank further enhances this duration by approximately 65% compared to the sensible TES case. Moreover, the study revealed that adjusting the PCM composition within the cascade TES significantly influenced both thermal power storage durations and pumping energy consumption. In summary, the recommended cascade PCM configuration for collective heating of buildings offers a balanced solution, ensuring prolonged stable thermal power production, elevated HTF outlet temperatures, and improved energy efficiency, presenting promising prospects for enhancing TES systems in district heating applications.
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Mikhailov, I. N., T. I. Mikhailova, M. Di Toro, V. Baran y Ch Briançon. "Collective dynamics of nuclear fusion: deformation changes and heating during the fusion". Nuclear Physics A 604, n.º 3 (julio de 1996): 358–84. http://dx.doi.org/10.1016/0375-9474(96)00166-2.
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Deng, Weichu, Zhongbing Shi, Peiwan Shi, Feng Zhang, Xin Yu, Zengchen Yang, Min Jiang et al. "Design of the Collective Thomson Scattering System on HL-3 tokamak". EPJ Web of Conferences 313 (2024): 03005. http://dx.doi.org/10.1051/epjconf/202431303005.
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A collective Thomson scattering (CTS) diagnostic system is being developed to measure fastion velocity distribution on HL-3 tokamak. A 140 GHz gyrotron belonging to electron cyclotron resonance heating (ECRH) system would be used to generate probe beam. The scattering spectra among HL-3 parameter ranges are calculated to assess diagnostic feasibility. Scattering signals will be detected by a heterodyne system, which is proposed to optimize diagnostic performance.
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Klimchuk, James A. "Key aspects of coronal heating". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, n.º 2042 (28 de mayo de 2015): 20140256. http://dx.doi.org/10.1098/rsta.2014.0256.
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We highlight 10 key aspects of coronal heating that must be understood before we can consider the problem to be solved. (1) All coronal heating is impulsive. (2) The details of coronal heating matter. (3) The corona is filled with elemental magnetic stands. (4) The corona is densely populated with current sheets. (5) The strands must reconnect to prevent an infinite build-up of stress. (6) Nanoflares repeat with different frequencies. (7) What is the characteristic magnitude of energy release? (8) What causes the collective behaviour responsible for loops? (9) What are the onset conditions for energy release? (10) Chromospheric nanoflares are not a primary source of coronal plasma. Significant progress in solving the coronal heating problem will require coordination of approaches: observational studies, field-aligned hydrodynamic simulations, large-scale and localized three-dimensional magnetohydrodynamic simulations, and possibly also kinetic simulations. There is a unique value to each of these approaches, and the community must strive to coordinate better.
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Poedts, Stefaan, Wolfgang Kerner y Marcel Goossens. "Alfvén-wave heating in resistive MHD". Journal of Plasma Physics 42, n.º 1 (agosto de 1989): 27–58. http://dx.doi.org/10.1017/s0022377800014173.
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Resonant absorption of Alfvén waves in tokamak plasmas is studied numerically using the linearized equations of resistive magnetohydrodynamics. A numerical code based on a finite-element discretization is used for determining the stationary state of a cylindrical plasma column that is excited by an external periodic driver. The energy dissipation rate in the stationary state is calculated and the dependence of the plasma heating on electrical resistivity, the equilibrium profiles, and the wavenumbers and frequency of the external driver is investigated. Resonant absorption is extremely efficient when the plasma is excited with a frequency near that of a so-called ‘collective mode’. The heating of a plasma by driving it at the frequencies of discrete Alfvén waves is also investigated.
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Van de Putte, Stijn, Marijke Steeman y Arnold Janssens. "The Building Energy Performance Gap in Multifamily Buildings: A Detailed Case Study Analysis of the Energy Demand and Collective Heating System". Sustainability 17, n.º 1 (1 de enero de 2025): 252. https://doi.org/10.3390/su17010252.
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The building energy performance gap, resulting from a discrepancy between the actual energy use and theoretical calculations, remains a persistent issue in building design. This study examines the energy performance of three multifamily buildings with a collective heating system powered by gas boilers and solar collectors: two that underwent deep renovation and one newly built. An extensive on-site monitoring system provides detailed data on both the heating demand and the final energy use. To ensure comparability, the total energy use of each unit is normalised using the energy signature method. The findings show the large spread of actual energy demands due to a wide variation in user profiles. The majority of dwellings have an actual energy use that is significantly higher than calculated, which is largely attributable to space heating. The gap is further exacerbated by substantial heat losses within the building’s heating system and by limited gains from the solar collectors, indicating discrepancies between design models and operational realities. To bridge this gap, there is a need for rigorous commissioning processes, at least during the initial operation phase start-up and ideally continuously. This can ensure more effective utilisation of renewable energy sources and reduce energy inefficiencies.
Tesis sobre el tema "Collective heating"
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Carlson, Michael Thomas. "Collective Heating Effects in Nanoparticle Solutions and Photothermal Studies of Gold Nanostructures Using a Novel Optical Thermal Sensor". Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1336409979.
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Choi, Sung In. "Smart Localized Heating Control System With Human Movement Tracking". Master's thesis, Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/407171.
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Electrical EngineeringM.S.E.E.
According to the U.S. energy consumption survey in 2012, about 25% of the commercial and 42% of the residential building energy were used for heating. Despite the development of new and more efficient Heating, Ventilation, and Air Conditioning (HVAC) systems over the years, the high energy consumption in heating is still one of the major energy efficiency issues. Studies showed that decreasing HVAC operating temperature set points by 4°F will result in energy savings of 15% or more. Thus, the smart localized heating control (SLHC) system was designed and prototyped to provide localized heat directly to a person so that HVAC can run at a lower temperature set point. SLHC detects human movement and delivers the heat based on the result of the target location estimation and temperature measurement feedback. To detect the human movement, image processing techniques were used; image segmentation, mass center detection, background subtraction using the Mixture of Gaussian model, and human feature detection. In SLHC, a near-infrared heater and a tracking function were used to provide an instant and a direct heat to the person in order to minimize wasting energy. The SLHC system is divided into the sensing and processing (SP) and the heating and regulating (HR) subsystem. The SP’s primary function is to process captured video images and measured temperature data. SP also generates and sends the heater operating signal to HR. HR purposes to control the heater’s direction and power based on the signal. The communication between SP and HR was established through Wi-Fi enabled development platform. The SLHC prototype successfully processed the sensing data and transmitted the control signal. The result shows that it detected human movement and estimated the person’s location in 3D space within 10% margin of error. Also, it delivered the focused heat to the surface of the human body and increased the temperature by 10.0°F in 3 minutes at the distance of 1.5m away from the heater. This cost-effective, wireless, and localized heating system demonstrates the potential to improve energy efficiency in buildings.
Temple University--Theses
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Abbott, Ashley Burnett. "Analysis of Thermal Energy Collection from Precast Concrete Roof Assemblies". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10082.
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The development of precast concrete housing systems provides an opportunity to easily and inexpensively incorporate solar energy collection by casting collector tubes into the roof structure. A design is presented for a precast solar water heating system used to aid in meeting the space and domestic water heating loads of a single family residence. A three-dimensional transient collector model is developed to characterize the precast solar collector's performance throughout the day. The model describes the collector as a series of segments in the axial direction connected by a fluid flowing through an embedded tube. Each segment is represented by a two-dimensional solid model with top boundary conditions determined using a traditional flat plate solar collector model for convection and radiation from the collector cover plate.
The precast collector is coupled to a series solar assisted heat pump system and used to meet the heating needs of the residence. The performance of the proposed system is compared to the performance of a typical air to air heat pump. The combined collector and heat pump model is solved using Matlab in conjunction with the finite element solver, Femlab.
Using the system model, various non-dimensional design and operating parameters were analyzed to determine a set of near optimal design and operating values. The annual performance of the near optimal system was evaluated to determine the energy and cost savings for applications in Atlanta, GA and Chicago, IL. In addition, a life cycle cost study of the system was completed to determine the economic feasibility of the proposed system. The results of the annual study show that capturing solar energy using the precast collector and applying the energy through a solar assisted heat pump can reduce the electricity required for heating by more than 50% in regions with long heating seasons. The life cycle cost analysis shows that the energy savings justifies the increase in initial cost in locations with long heating seasons but that the system is not economically attractive in locations with shorter heating seasons.Master of Science
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Cabezas-Rivière, Enzo. "Identifier, comprendre et résoudre les freins à une meilleure maîtrise des consommations de chauffage et du confort en France". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0258.
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Dans le contexte environnemental et économique actuel, il est primordial que chaque individu ait les clefs pour maitriser ses consommations de chauffage tout en maintenant un niveau de confort satisfaisant. Cependant, des freins peuvent limiter cette maitrise de l’énergie et du confort. Par exemple, dans les immeubles en chauffage collectif en France, la répartition des charges entre les logements se fait traditionnellement au prorata de la surface, ce qui peut décourager l’adoption et le maintien de comportements sobres en énergie. Pour y remédier, la loi Élan vise à individualiser les frais de chauffage pour inciter les foyers à économiser de l’énergie. Cependant, des études menées sur certains logements et bâtiments ont montré que la répartition des frais de chauffage n’est pas le seul frein à davantage de sobriété énergétique. Ainsi, cette thèse s’est d'abord attachée à identifier et à comprendre les freins à une meilleure maîtrise des consommations de chauffage et du confort dans les logements français équipés de chauffage collectif, représentant environ six millions de foyers. Pour y parvenir, une enquête a été réalisée. Les résultats ont montré que les factures de chauffage sont souvent difficiles à consulter et à comprendre, tout comme la répartition des frais de chauffage. De plus, les répondants ont exprimé le besoin d’informations supplémentaires, telles que des conseils personnalisés ou des données sur l’impact environnemental de leur consommation. Les résultats ont également révélé que l’absence de systèmes de programmation et de pilotage à distance des radiateurs dissuade les occupants d’adopter et de maintenir des comportements économes. Ensuite, les travaux de cette thèse se sont concentrés sur la résolution de ces freins. Pour cela, une méthodologie a été élaborée afin d’améliorer à la fois l’environnement technique et informatif des usagers. Traditionnellement, pour inciter les individus à économiser de l’énergie, une ou plusieurs interventions sont mises en place. Cependant, peu d’études proposent une approche permettant de cibler les interventions pertinentes en fonction des caractéristiques des individus. Pour déterminer les interventions à employer, un modèle de changement de comportement a été utilisé en raison de son adaptation à la gestion de l’énergie. L’évaluation des facteurs psychosociaux constituant ce modèle a permis d’identifier les interventions les plus appropriées pour chaque individu. De plus, les informations fournies dans le cadre de ces interventions ont été personnalisées en fonction des habitudes et des centres d’intérêt des occupants, afin de les encourager à les consulter. Pour améliorer la commodité d’usage de l’environnement technique, des robinets thermostatiques connectés ont été installés, permettant un pilotage et une programmation à distance des radiateurs à faible coût. Ces dispositifs transmettent des données sur la température ambiante et la consigne appliquée par les usagers, permettant ainsi de fournir des conseils personnalisés sur l’utilisation du chauffage. Ces conseils incluaient également une estimation des économies réalisables en suivant les recommandations. Pour calculer de manière fiable ces économies potentielles ainsi que celles déjà réalisées, des modèles de simulation thermique dynamique ont été développés. Enfin, la méthodologie a été expérimentée sur deux familles durant la période de chauffe 2023-2024. L’évaluation de cette expérimentation a pris en compte l’évolution des facteurs psychosociaux, les changements de comportement, les économies d’énergie réalisées, ainsi que l’évolution du confort des usagersIn the current environmental and economic context, it is crucial that each individual has the tools to manage their heating consumption while maintaining a satisfactory level of comfort. However, obstacles can limit this control over energy and comfort. For example, in buildings with collective heating in France, the distribution of charges between apartments is traditionally based on the proportional surface area, which may discourage the adoption and maintenance of energy-efficient behaviours. To address this, the Élan law aims to individualize heating costs to encourage households to save energy. However, studies conducted on certain dwellings and buildings have shown that the distribution of heating costs is not the only obstacle to greater energy efficiency.Thus, this thesis first aimed to identify and understand the barriers to better control of heating consumption and comfort in French dwellings equipped with collective heating, representing around six million households. To achieve this, a survey was conducted. The results showed that heating bills are often difficult to access and understand, as is the distribution of heating costs. Additionally, respondents expressed the need for additional information, such as personalized advice or data on the environmental impact of their consumption. The results also revealed that the absence of remote programming and control systems for radiators discourages occupants from adopting and maintaining energy-efficient behaviours.Next, the work of this thesis focused on overcoming these barriers. To this end, a methodology was developed to improve both the technical and informational environment for users. Traditionally, to encourage individuals to save energy, one or more interventions are implemented. However, few studies propose an approach that targets relevant interventions based on individual characteristics. To determine the interventions to be used, a behavior change model was employed due to its suitability for energy management. The evaluation of the psychosocial factors constituting this model helped identify the most appropriate interventions for each individual. Moreover, the information provided as part of these interventions was personalized according to the occupants' habits and interests, encouraging them to engage with it. To improve the ease of use of the technical environment, connected thermostatic valves were installed, allowing remote control and programming of radiators at a low cost. These devices transmit data on the ambient temperature and the setpoint applied by users, enabling personalized advice on heating usage. This advice also included an estimate of the savings achievable by following the recommendations. To reliably calculate these potential savings, as well as those already achieved, dynamic thermal simulation models were developed.Finally, the methodology was tested on two families during the 2023-2024 heating period. The evaluation of this experiment considered changes in psychosocial factors, behaviour, comfort and energy savings achieved
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Huffman, Matthew. "SOUNDING ROCKET REDESIGN AND OPTIMIZATION FOR PAYLOAD EXPANSION AND IN FLIGHT TELEMETRY TRANSMITTAL". Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2214.
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Due to renewed interest in the sub orbital rocket program of the Florida Space Authority and a surplus of Super Loki Sounding Rockets, an effort to improve the usefulness of this surplus is herein undertaken. Currently, the capacity of the payload compartment in the upper stage of the Super Loki system is very limited. A redesign of the upper stage will allow larger and more versatile payloads to be carried, assuming the appropriate design parameters are met. It has therefore been undertaken to create a design procedure that is comprehensive in scope in order to affect this redesign. This procedure includes five major components. These are the separation of the upper and lower stages, the stability of the vehicle, the altitude and velocity of the rocket, the mechanical loading and finally the aerodynamic heating. Semi-empirical methods were used whenever possible to allow comparison with experimental data. This procedure revealed that larger diameter upper stages might be used up to a reasonable maximum of four inches. The four-inch modification is found to be stable as were the smaller modifications considered. The altitude and velocity of the rocket were found via a simple Eulerian time stepping scheme resulting in an estimate of approximately 148,000ft for the four-inch dart. The mechanical loading analysis allowed for the material selection for the rocket components. Reinforced steel fins and carbon fiber tubing, for the payload section, are adequate to meet expected mechanical loads, those being, 16000psi for the fin section due to launcher forces, 22800psi for compressive plus torsion forces on the composite section and 18000psi for the ejection stresses. An ablative coating is considered necessary to counteract the 760ºF temperatures along the composite tube.M.S.A.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Aerospace Engineering
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Gil, Camilo. "An Optimal Control Approach for Determiniation of the Heat Loss Coefficient in an ICS Solar Domestic Water Heating System". Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2567.
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Water heating in a typical home in the U.S. accounts for a significant portion (between 14% and 25%) of the total home's annual energy consumption. The objective of considerably reducing the home's energy consumption from the utilities calls for the use of onsite renewable energy systems. Integral Collector Storage (ICS) solar domestic water heating systems are an alternative to help meet the hot water energy demands in a household. In order to evaluate the potential benefits and contributions from the ICS system, it is important that the parameter values included in the model used to estimate the system's performance are as accurate as possible. The overall heat loss coefficient (Uloss) in the model plays an important role in the performance prediction methodology of the ICS. This work presents a new and improved methodology to determine Uloss as a function of time in an ICS system using a systematic optimal control theoretic approach. This methodology is based on the derivation of a new nonlinear state space model of the system, and the formulation of a quadratic performance function whose minimization yields estimates of Uloss values that can be used in computer simulations to improve the performance prediction of the ICS system, depending on the desired time of the year and hot water draw profile. Simulation results show that predictions of the system's performance based on these estimates of Uloss are considerably more accurate than the predictions based on current existing methods for estimating Uloss.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering PhD
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Nitecki, Elena M. "Heating Up and Cooling Out at the Community College: The Potential of Student-Faculty Interactions to Contribute to Student Aspiration". Diss., Temple University Libraries, 2009. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/39408.
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Urban EducationPh.D.
This study examines the potential of faculty at the community college to positively influence, or "heat up," student aspirations. With increasing emphasis on graduation and transfer rates in higher education, the importance of micro-level interactions that shape student aspiration has been neglected. To better understand how individuals within the institution, especially faculty, contribute to student aspirations, this study attempts to bridge the "cooling out" and "heating up" literature in the context of the modern community college by recognizing the role of the individual academic program. Applying organizational theory from a systems perspective, as well as the theories of Paolo Freire, the study examines the nature of student-faculty interactions that have the potential to contribute to student aspiration in the context of institutional limitations. The participants include students and faculty in three academic programs that have different approaches to student success within one urban community college. The case study involves a combination of qualitative approaches, including interviews and observations. The study inductively examines student-faculty interactions and their potential to contribute to student aspirations within three different academic programs. The most significant barriers to student success and increasing aspirations are found on the institutional level. These limitations, including bureaucratic confusion, advisement issues, remediation, variation in attendance policies, financial constraints, and lacking a cohesive institutional culture and commitment, have the potential to "cool out" student aspiration, as supported in the majority of the community college literature on this topic. However, the mezzo-level effects of programs and the micro-level practices of the individuals hold substantial potential in terms of "heating up" student aspiration. Programs vary in the degree to which they handle the institutional limitations. Programs that take an active role in mediating between the limiting institutional barriers and students provide a cushioning program-wide protection from the cooling out elements. The micro-level interactions between individual students and faculty also hold potential to heat up by helping students navigate the systematic confusion that seems characteristic of the community college. Therefore, this study suggests that there is hope for the community college in fulfilling its promise of educational opportunity. Macro-level institutional challenges, as well as larger societal inequalities, are substantial and pervasive at the community college and solutions are often limited by financial constraints. However, the programs and individuals within the community college hold promise. The study suggests that the roles of the program and the individual are instrumental in shaping student aspiration.
Temple University--Theses
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Chen, Sen-Yong. "Phonon Modulation by Polarized Lasers for Material Modification". Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5159.
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Magnetic resonance imaging (MRI) has become one of the premier non-invasive diagnostic tools, with around 60 million MRI scans applied each year. However, there is a risk of thermal injury due to radiofrequency (RF) induction heating of the tissue and implanted metallic device for the patients with the implanted metallic devices. Especially, MRI of the patients with implanted elongated devices such as pacemakers and deep brain stimulation systems is considered contraindicated. Many efforts, such as determining preferred MRI parameters, modifying magnetic field distribution, designing new structure and exploring new materials, have been made to reduce the induction heating. Improving the MRI-compatibility of implanted metallic devices by modifying the properties of the existing materials would be valuable. To evaluate the temperature rise due to RF induction heating on a metallic implant during MRI procedure, an electromagnetic model and thermal model are studied. The models consider the shape of RF magnetic pulses, interaction of RF pulses with metal plate, thermal conduction inside the metal and the convection at the interface between the metal and the surroundings. Transient temperature variation and effects of heat transfer coefficient, reflectivity and MRI settings on the temperature change are studied. Laser diffusion is applied to some titanium sheets for a preliminary study. An electromagnetic and thermal model is developed to choose the proper diffusant. Pt is the diffusant in this study. An electromagnetic model is also developed based on the principles of inverse problems to calculate the electromagnetic properties of the metals from the measured magnetic transmittance. This model is used to determine the reflectivity, dielectric constant and conductivity of treated and as-received Ti sheets. The treated Ti sheets show higher conductivity than the as-received Ti sheets, resulting higher reflectivity. A beam shaping lens system which is designed based on vector diffraction theory is used in laser diffusion. Designing beam shaping lens based on the vector diffraction theory offers improved irradiance profile and new applications such as polarized beam shaping because the polarization nature of laser beams is considered. Laser Pt diffusion are applied on the titanium and tantalum substrates using different laser beam polarizations. The concentration of Pt and oxygen in those substrates are measured using Energy Dispersive X-Ray Spectroscopy (EDS). The magnetic transmittance and conductivity of those substrates are measured as well. The effects of laser beam polarizations on Pt diffusion and the magnetic transmittance and conductivity of those substrates are studied. Treated Ti sheets show lower magnetic transmittance due to the increased conductivity from diffused Pt atoms. On the other hand, treated Ta sheets show higher magnetic transmittance due to reduced conductivity from oxidation. Linearly polarized light can enhance the Pt diffusion because of the excitation of local vibration mode of atoms. Laser Pt diffusion and thermo-treatment were applied on the Ta and MP35N wires. The Pt concentration in laser platinized Ta and MP35N wires was determined using EDS. The ultimate tensile strength, fatigue lives and lead tip heating in real MRI environment of those wires were measured. The lead tip hating of the platinized Ta wires is 42 % less than the as-received Ta wire. The diffused Pt increases the conductivity of Ta wires, resulting in more reflection of magnetic field. In the case of the platinized MP35N wire, the reduction in lead tip heating was only 1 °C due to low concentration of Pt. The weaker ultimate tensile strength and shorter fatigue lives of laser-treated Ta and MP35N wires may attribute to the oxidation and heating treatment.Ph.D.
Doctorate
Optics and Photonics
Optics and Photonics
Optics
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Lin, Yu y 林佑. "Applications of copper nanowires: transparent conductive electrode and near-infrared light induced collective plasmonic heating phenomena". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/q6xbnz.
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碩士國立清華大學
化學工程學系
102
In this study, thin, long, and well-dispersed copper nanowires were obtained via the seed-mediated growth in an organic solvent-based synthesis. The mean length and diameter of nanowire are about 38.7 μm and 49 nm with a high aspect ratio of 790. Large area conducting films was prepared by a fast, low-cost, simple spray deposition of copper nanowires dispersions. These wires were used for nanowire conducting films since their relatively long length is advantage in lowering the sheet resistance. As-synthesized copper nanowires dispersion was sprayed to create highly transparent conductive electrode from 2×2 cm2 to 6×6 cm2, 6.5×10 cm2 even 6×25 cm2. We can use copper nanowires conducting electrode as a touch switch for much equipment such as light LED array, turn on a computer, etc. We also exploit the photothermal effect of copper nanowires, using copper nanowires fabric as a reactor to do some nanomaterials synthesis. Fabric was illuminated by an 808 nm cw laser with different power to control the fabric temperature in order to do different nanomaterials synthesis. Many materials have been successfully synthesized.
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Sisken, Laura. "Distribution of Laser Induced Heating in Multi-Component Chalcogenide Glass and its Associated Effects". Master's thesis, 2014. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6187.
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Chalcogenide glasses are well known to have good transparency into the infrared spectrum. These glasses though tend to have low thresholds as compared to oxide glasses for photo-induced changes and thermally-induced changes. Material modification such as photo-induced darkening, bleaching, refractive index change, densification or expansion, ablation of crystallization have been demonstrated, and are typically induced by a thermal furnace-based heat treatment, an optical source such as a laser, or a combination of photo-thermal interactions. Solely employing laser-based heating has an advantage over a furnace, since one has the potential to be able to spatially modify the materials properties with much greater precision by moving either the beam or the sample.
The main properties of ChG glasses investigated in this study were the light-induced and thermally-induced modification of the glass through visible microscopy, white light interferometry, and Raman spectroscopy. Additionally computational models were developed in order to aid in determining what temperature rise should be occurring under the conditions used in experiments.
It was seen that ablation, photo-expansion, crystallization, and melting could occur for some of the irradiation conditions that were used. The above bandgap energy simulations appeared to overestimate the maximum temperature that should have been reached in the sample, while the below bandgap energy simulations appeared to underestimate the maximum temperature that should have been reached in the sample. Ultimately, this work produces the ground work to be able to predict and control dose, and therefore heating, to induce localized crystallization and phase change.M.S.
Masters
Optics and Photonics
Optics and Photonics
Optics and Photonics
Libros sobre el tema "Collective heating"
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European Commission. Directorate-General for Energy y Joule-Thermie Programme, eds. Guaranteed results of collective thermal solar installations: Thermie programme action no SE17. Barcelona, Spain: Generalitat de Catalunya, Departament d'Indústria i Energia, Institut Català d'Energia, 1998.
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American Society of Heating, Refrigerating and Air-Conditioning Engineers., ed. Laboratory HVAC: A collection of ASHRAE papers. Atlanta, Ga: American Society of Heating, Refrigerating and Air-Conditioning Engineers, 1995.
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Centre EDF-GDF d'information du bâtiment (France), ed. La Bi-énergie dans l'habitat collectif et les bâtiments du tertiaire. Paris: Editions du Moniteur, 1989.
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Tschernitz, John L. Solar energy for wood drying using direct or indirect collection with supplemental heating: A computer analysis. Madison, WI: U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, 1986.
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Building Officials and Code Administrators International., International Conference of Building Officials. y Southern Building Code Congress International., eds. International codes, 2003: The complete collection. Falls Church, Va: International Code Council, Inc., 2000.
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Conservation, United States Congress Senate Committee on Energy and Natural Resources Subcommittee on Energy Regulation and. Improving the collection and dissemination of information of winter heating fuels and the EIA's report on heating oil markets: Hearing before the Subcommittee on Energy Regulation and Conservation of the Committee on Energy and Natural Resources, United States Senate, One Hundred First Congress, second session, on 2177 ... July 26, 1990. Washington: U.S. G.P.O., 1990.
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Conservation, United States Congress Senate Committee on Energy and Natural Resources Subcommittee on Energy Regulation and. Improving the collection and dissemination of information of winter heating fuels and the EIA's report on heating oil markets: Hearing before the Subcommittee on Energy Regulation and Conservation of the Committee on Energy and Natural Resources, United States Senate, One Hundred First Congress, second session, on S. 2177 ... July 26, 1990. Washington: U.S. G.P.O., 1990.
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Pfister, Thomas y Martin Schweighofer. Energy Cultures as Sociomaterial Orders of Energy. Editado por Debra J. Davidson y Matthias Gross. Oxford University Press, 2018. http://dx.doi.org/10.1093/oxfordhb/9780190633851.013.10.
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This chapter discusses energy systems and energy transformations from a perspective on culture. First, it outlines three essential elements of energy cultures: everyday practices as ground layer, collective representations of the order of energy as second layer, and knowledge as a dynamic link mediating between these layers. The subsequent two sections use the examples of sustainable electricity in the European Union and Germany, as well as various efforts to create more sustainable ways of heating and housing, to illustrate how energy cultures operate and how they become particularly visible when contested. The suggested perspective, therefore, analyzes such transformations in terms of knowledge struggles in which different actors seek to promote their envisioned energy cultures. Utilizing specific knowledge-centered practices, these actors attempt to intervene in everyday practices of energy production, use, and distribution, as well as in collective representations of the roles, values, and meanings of energy within a society.
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Page, Phil y Ian Littlechilds. Four Heatons the Postcard Collection. Amberley Publishing, 2015.
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Devlyn, Tracey, Jennifer Jakes, Eliza Knight, Tara Kingston y Jeannie Ruesch. Heating It up - Collection One: One Hero at a Time. TDC Creations, Inc., 2014.
Buscar texto completoCapítulos de libros sobre el tema "Collective heating"
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Feeney, Margaret. "Collective invention: a travelling artist's perspective." En Creative tourism: activating cultural resources and engaging creative travellers, 38–45. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789243536.0005.
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Abstract People travel because they are searching. They are not content to download experience through mediated internet platforms, or to find themselves curated into a vat of preserved content, steeped in academic salt. Travelling is free of the dreary imperatives of everyday life; we step into the world to enlarge our frame of reference, not to be poked into another grid of curated meaning. Tourist hotspots everywhere have been heating up as fast as the climate, and unique cultural sensibilities and practices are perishing in the glare of the demands of the modern tourist. The researcher uses The Water Systems and the Stencil project as case studies in relation to the elements of effective workshop creation.
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Neves-Medeiros, Rui, Anastassia Krusteva, Stanimir Valtchev, George Gigov y Plamen Avramov. "Experimental Study on Induction Heating Equipment Applied in Wireless Energy Transfer for Smart Grids". En Technological Innovation for Collective Awareness Systems, 486–93. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-54734-8_54.
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Van de Putte, Stijn, Niels Maenhout, Marijke Steeman y Arnold Janssens. "Performance Analysis of the Collective Heating System in Three Multifamily Buildings Using in Situ Monitoring". En Lecture Notes in Civil Engineering, 97–103. Singapore: Springer Nature Singapore, 2024. https://doi.org/10.1007/978-981-97-8313-7_15.
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Rozis, Jean-François y Alain Guinebault. "7. Details of collection, storage and distribution". En Solar Heating in Cold Regions, 105–12. Rugby, Warwickshire, United Kingdom: Practical Action Publishing, 1996. http://dx.doi.org/10.3362/9781780445977.007.
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Włodarczyk-Gębik, Agnieszka, Aleksandra Gabriel, Maria Dubis y Monika Machowska. "KTP—Collectively Improving Air Quality in Krakow: A New Air Quality Plan for the Małopolska Region". En Springer Series in Design and Innovation, 67–78. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-78733-2_7.
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AbstractKTP’s project relates to the challenge of air pollution and the need to improve quality of life in Kraków and the Kraków Metropolitan Area. The aim is to improve the quality of the air by motivating citizens to change their ecological attitudes, transport and heating habits and support decision makers with relevant tools and instruments for better co-creation of local new policies with a user-centered approach.
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Vigne, Jean‑Denis, François Briois y Jean Guilaine. "Utilitarian devices and facilities of the residential areas". En Klimonas, 227–34. Paris: CNRS Éditions, 2024. http://dx.doi.org/10.4000/129kb.
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The utilitarian devices and facilities identified at Klimonas include sediment extraction pits, hearth pits and heating plates, small mosaic-lined pits, offering pits and possible storage pits, as well as potential water collection and storage systems. This chapter deals more specifically with the hearth pits found in the residential buildings, for which 19 examples show a marked standardisation in the form of round-bottomed models (60 cm long and 30 cm deep) devoid of any stones or other arrangement except an enigmatic small side pit (nightlight?). They were almost always located inside the buildings; the only exception being B800 that was associated with a large external fire pit and an internal heating plate. Compared with those of the PPNA continental sites, the equipment of Klimonas appears poorer, less sophisticated and more reminiscent of certain mainland Natufian sites. Stone was seldom used for utilitarian devices or buildings. These, probably local, specificities may be due to the remoteness of Klimonas from the main centres of the PPNA culture.
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Rentala, Girish Srivatsa y Yimin Zhu. "Investigating the Ability of Immersive Virtual Environments to Facilitate Occupant Thermal State Data Collection Involving Face Masks". En CONVR 2023 - Proceedings of the 23rd International Conference on Construction Applications of Virtual Reality, 100–108. Florence: Firenze University Press, 2023. http://dx.doi.org/10.36253/10.36253/979-12-215-0289-3.10.
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This study examines the capability of an immersive virtual environment (IVE–based) experimental protocol to support occupant thermal state (sensation, acceptability, and comfort) data collection when participants wear face masks. Specifically, the goal is to see if there is a change in local thermal states due to face covering and would such a change affect overall thermal states. A between-subject experiment was conducted with fifty-four participants (27 masked; 27 unmasked) who were exposed to three-step temperatures (18.3ºC, 23.8ºC, and 29.4ºC) in a climate chamber under both cooling and heating sequences. In masked IVE experiments, participants donned a face mask and viewed the chamber's virtual model on a head-mounted display. In contrast, in unmasked IVE experiments, participants didn't use a face mask. Skin temperatures and overall/local thermal state responses were collected during the experiments. They were then statistically compared between masked IVE and unmasked IVE experiments. The results suggest that forehead temperature was significantly different under all step temperatures in the cooling sequence, with mean forehead temperature being larger in masked IVE than in unmasked IVE experiments. Furthermore, in masked IVE experiments, thermal sensation in the forehead, neck, and upper-back increased while the thermal acceptability in those same skin sites decreased, but this difference was not statistically significant. Also, in masked IVE experiments, the overall thermal sensation increased, whereas both the overall thermal acceptability and comfort decreased when compared with unmasked IVE experiments. Nonetheless, this difference was not statistically significant. To summarize, wearing a face mask didn't affect the participant's overall and local thermal states in IVEs, although few statistical differences were observed in skin temperatures
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Rentala, Girish Srivatsa y Yimin Zhu. "Investigating the Ability of Immersive Virtual Environments to Facilitate Occupant Thermal State Data Collection Involving Face Masks". En CONVR 2023 - Proceedings of the 23rd International Conference on Construction Applications of Virtual Reality, 100–108. Florence: Firenze University Press, 2023. http://dx.doi.org/10.36253/979-12-215-0289-3.10.
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This study examines the capability of an immersive virtual environment (IVE–based) experimental protocol to support occupant thermal state (sensation, acceptability, and comfort) data collection when participants wear face masks. Specifically, the goal is to see if there is a change in local thermal states due to face covering and would such a change affect overall thermal states. A between-subject experiment was conducted with fifty-four participants (27 masked; 27 unmasked) who were exposed to three-step temperatures (18.3ºC, 23.8ºC, and 29.4ºC) in a climate chamber under both cooling and heating sequences. In masked IVE experiments, participants donned a face mask and viewed the chamber's virtual model on a head-mounted display. In contrast, in unmasked IVE experiments, participants didn't use a face mask. Skin temperatures and overall/local thermal state responses were collected during the experiments. They were then statistically compared between masked IVE and unmasked IVE experiments. The results suggest that forehead temperature was significantly different under all step temperatures in the cooling sequence, with mean forehead temperature being larger in masked IVE than in unmasked IVE experiments. Furthermore, in masked IVE experiments, thermal sensation in the forehead, neck, and upper-back increased while the thermal acceptability in those same skin sites decreased, but this difference was not statistically significant. Also, in masked IVE experiments, the overall thermal sensation increased, whereas both the overall thermal acceptability and comfort decreased when compared with unmasked IVE experiments. Nonetheless, this difference was not statistically significant. To summarize, wearing a face mask didn't affect the participant's overall and local thermal states in IVEs, although few statistical differences were observed in skin temperatures
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De Simone, Marilena, Philip Griffiths, Daniele Campagna y Moses Itanola. "Energy Systems and Building Services Level". En Springer Tracts in Civil Engineering, 43–68. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-73490-8_3.
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AbstractResearch and technological developments have mainly focused on increasing the energy efficiency of buildings, improving the thermal properties of the envelope and reducing energy consumption. Another critical issue is related to waste reduction and implementation of circular economy frameworks. Moreover, building services have a significant impact upon the health of users and any application of the circular economy has to consider the effect on the occupants’ well-being. In this chapter, two aspects are considered: the first relates to the building systems which utilise energy for heating, cooling, ventilation, electrical supply; the second concerns the systems converting the energy from the sun, wind, and soil. Regarding the usage of energy in buildings, the types of materials applied in building services are categorised including metals, plastics, electronic components, etc. The barriers to the adoption of circular supply chain management are illustrated collecting information from the literature, especially in the air conditioning sector. Then, the electricity and thermal energy production from renewable sources are presented in the light of implementing a circular economy at the building and urban scale. Solar, both PV and thermal, wind, and geothermal technologies are illustrated in terms of trends in installation and prediction of waste production. Best practices of recycling are illustrated from projects, industrial processes, and companies. The collected information highlights the need for closer collaboration between the involved stakeholders, starting from the citizens and extending to all members of the design, construction, and building management professions.
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Kizilkale, A. C. y R. P. Malhamé. "Collective Target Tracking Mean Field Control for Markovian Jump-Driven Models of Electric Water Heating Loads". En Control of Complex Systems, 559–84. Elsevier, 2016. http://dx.doi.org/10.1016/b978-0-12-805246-4.00020-3.
Texto completoActas de conferencias sobre el tema "Collective heating"
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Dowling, Alexander W. "Artificial Intelligence and Machine Learning for Sustainable Molecular-to-Systems Engineering". En Foundations of Computer-Aided Process Design, 22–31. Hamilton, Canada: PSE Press, 2024. http://dx.doi.org/10.69997/sct.114705.
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Sustainability encompasses many wicked problems involving complex interdependencies across social, natural, and engineered systems. We argue holistic multiscale modeling and decision-support frameworks are needed to address multifaceted interdisciplinary aspects of these wicked problems. This review highlights three emerging research areas for artificial intelligence (AI) and machine learning (ML) in molecular-to-systems engineering for sustainability: (1) molecular discovery and materials design, (2) automation and self-driving laboratories, (3) process and systems-of-systems optimization. Recent advances in AI and ML are highlighted in four contemporary application areas in chemical engineering design: (1) equitable energy systems, (2) decarbonizing the power sector, (3) circular economies for critical materials, and (4) next-generation heating and cooling. These examples illustrate how AI and ML enable more sophisticated interdisciplinary multiscale models, faster optimization algorithms, more accurate uncertainty quantification, smarter and faster data collection, and incorporation of diverse stakeholders into decision-making processes, improving the robustness of engineering and policy designs while focusing on the multifaceted goals and constraints in wicked problems.
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CHIEN, L. H., A. SERGEEV, N. VAGIDOV, V. MITIN y S. BIRNER. "ELECTRON HEATING IN QUANTUM-DOT STRUCTURES WITH COLLECTIVE POTENTIAL BARRIERS". En Proceedings of the Workshop on Frontiers in Electronics 2009. WORLD SCIENTIFIC, 2013. http://dx.doi.org/10.1142/9789814383721_0012.
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Yu-Qing Lou. "On the collective appearance of coronal loops and the resistive heating instability". En Electromechanical Coupling of the Solar Atmosphere. AIP, 1992. http://dx.doi.org/10.1063/1.42868.
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Meessens, Arno, Lucas Verleyen, Wouter Peere, Wim Boydens y Lieve Helsen. "Micro energy communities: collective residential heating system retrofits for CO₂ emissions abatement". En 2023 Building Simulation Conference. IBPSA, 2023. http://dx.doi.org/10.26868/25222708.2023.1568.
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Čugalj, Jovana, Jasmina Pekez, Jelena Stojanov y Aleksandar Ašonja. "APPLICATION OF STATISTICAL METHODS IN ORDER TO DETERMINE THE LEVEL OF ENERGY EFFICIENCY". En XIV International Conference on Industrial Engineering and Environmental Protection, 191–97. University of Novi Sad Technical Faculty “Mihajlo Pupin” Zrenjanin, Republic of Serbia PROCEEDINGS of the XIV International Conference on Industrial Engineering and Environmental Protection IIZS 2024 Zrenjanin, October 3-4, 2024., 2024. http://dx.doi.org/10.46793/iizs24.191c.
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The study explores the state of energy efficiency in residential buildings in the city of Zrenjanin through an analysis of a survey conducted among 662 respondents. The results indicate a prevalent issue of the inability for collective investment in the energy efficiency of communal residential buildings compared to single-family homes. By using the Chi-square test of independence, a statistically significant relationship between the type of residential property and the presence of external thermal insulation was discovered. Additionally, a moderate dependence between the age of the heating system and the need for additional heating was identified. The research’s conclusion suggests the need for subsidies to improve the energy efficiency of residential buildings, especially multi-family complexes, to achieve sustainability and reduce energy consumption in the urban environment of Zrenjanin.
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O'Leary, Ceara. "Community Resilience Hubs: Everyday and Emergency Infrastructure in Detroit’s Neighborhoods". En 111th ACSA Annual Meeting Proceedings. ACSA Press, 2023. http://dx.doi.org/10.35483/acsa.am.111.60.
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In Detroit, community hubs are emerging as essential sites for a myriad of services contributing to both short term disaster response and long term community resilience. Community hubs have long been spaces of convening, information sharing and other elements of social infrastructure for all ages. Increasingly, hubs are intentional spaces for cultural production and community cohesion, contributing to strong neighborhood networks, as well as sites for disaster response, including heating and cooling in cases of emergency and provision of health supplies and food. This paper documents an ongoing research-based professional project focusing on existing community resilience hubs in two Detroit neighborhoods that meet everyday community needs and offer opportunities for a more robust collective network that integrates emergency preparedness and building performance to enable function in times of crisis. This work includes study of hubs in other cities and considers the link between cultural and climate resilience and how community hubs are spaces for both. This project is part of a larger collaborative planning process that centers resilience and health equity outcomes, focusing on access to resources in Detroit neighborhoods of varying density. This includes visions for current and future hubs that contribute to local definitions of resiliency.
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Tandler, John J. "Thermal Collection and Heating Device for Spas". En American Solar Energy Society National Solar Conference 2017. Freiburg, Germany: International Solar Energy Society, 2017. http://dx.doi.org/10.18086/solar.2017.04.03.
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Lefcort, Malcolm D. y E. L. S. (Ted) Skodje. "Sawmill, Wood Waste Fuelled, 100% Recuperated, 5 MW Gas Turbine Co-Generation Plant". En ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-062.
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Sawmills in the Canadian province of British Columbia (BC) will soon be confronted with a collective wood waste disposal problem (bark, sawdust and shavings) of about 3 Million bone dry tonne/y at an average wet basis moisture content of about 45%. About 40 existing sawmill beehive burners presently incinerate this waste. Emissions from these beehive burners exceed current provincial particulate limits. Markets for the waste — board plants, sawdust digesters, charcoal plants, etc. — are limited. The economics of 25 to 50 MW wood-fired, steam power plants is poor. 6¢/kW.h is needed to finance a plant; the major utility offers 2¢/kW.h. This paper describes a 3 MW to 5 MW, Nuovo Pignone PGT-5 co-generation plant fuelled by the 2000°F (1093°C) exhaust from a Heuristic EnvirOcycler, a two-stage, wood waste incinerator. The exhaust meets BC’s particulate limit of 0.052 grains/dscf (120 mg/Nm3). 37 to 65 Million Btu/h (39 to 68 GJ/h) of waste heat can be recovered from the system exhausts. In this application the PGT-5’s external combustion chamber is replaced by a “recuperator”, i.e., a high temperature, gas-to-air, heat exchanger. Two variations of the basic system are examined. One features a larger than necessary EnvirOcycler to generate additional steam in the waste heat boiler. The other variation discusses heating 1,550°F (843°C) air from the recuperator up to 1,796°F (980°C) with natural gas. The extra power generated can cost as little as 1.9¢/kW.h.
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Schmaltz, Kevin. "Bio-Generated Greenhouse Heating Project". En ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41979.
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A 30′ × 60′ greenhouse is being installed on the Western Kentucky University Agriculture Department campus farm that will be heated during winter by energy captured during the decomposition of leaves into compost. The bio-generated heat collection and distribution system was designed, and is currently being built and tested by undergraduate mechanical engineering students at WKU. Currently, the WKU Agriculture Department takes all leaves collected by the city of Bowling Green, processing and selling the resulting compost. While the leaves are composting, a temperature of over 150 °F is reached in the center of the leave piles. Student teams have designed and are installing a water piping system below the leaves to capture the waste heat and deliver the water to a root-zone heating system in the greenhouse. The design also includes a subsurface storage tank and auxiliary heating system to extend the capacity of the heating system. It is intended that WKU Agriculture will be able to operate the greenhouse for educational purposes throughout the year, and also provide the design to regional farmers who currently have greenhouses but cannot afford to heat them during Kentucky winters. This paper will detail the design of the heat collection system below the composting leaves, including sizing calculations and experimental verification, to permit uninterrupted composting activities. The root-zone heating system design will also be covered, including sizing calculations of the piping installation within sand beds in the greenhouse. The overall system control, energy storage and supplemental heating will also be discussed. The goal of the project has been to evaluate the feasibility of a cost-effective agricultural heating system for use in moderate climates throughout the United States.
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Schmuttenmaer, C. A., M. Aeschlimann, R. J. D. Miller, D. Mantell, J. Cao y Y. Gao. "Femtosecond Photoemission Studies of Electron Relaxation at Cu Surfaces". En International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/up.1994.tuc.4.
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A number of recent studies have illustrated the importance of photoexcited electrons in surface reactions at metal surfaces. This work focuses on directly determining the relaxation dynamics for photoexcited electrons at Cu(100) surfaces. This particular surface is important as recent observations for photoinduced desorption of CO have found quantum yields as high as 15% for the hot electron reaction channel at high laser fluences.1 Equal pulse correlation studies employing 3 eV pulses (50-60 fs) with both parallel and crossed polarization and low energy (<100 nJ/cm2) have been used to characterize the intrinsic electron relaxation dynamics in the absence of excess lattice heating or transient collective effects. This low energy limit corresponds to photoinduced surface chemistry employing conventional low flux CW light sources such as arc lamps. These results are shown in Figure 1. The inset shows the observed photoemission spectrum. The highest energy electrons give a pulse width limited response function which can be used to deduce the slower relaxation dynamics of the lower energy electrons. The slower relaxation dynamics are clearly resolved as a broadening in the FWHM of the two pulse correlation of the photoemitted electron at specific energies. The deconvolved relaxation times for the electron energy distribution are shown in which the solid line through the data is a fit to a calculation based on Fermi liquid theory for electron relaxation scaled by a factor of 2.45. The extent of this agreement for the electron relaxation dynamics at a single crystal surface is similar to the relaxation dynamics observed previously for polycrystalline gold surfaces at higher fluences.2 At lower energies above EF, hot electron transport effects become noticeable and can be understood in terms of a ballistic transport model. These results fully characterize the non-radiative relaxation of electrons at low fluence and peak power.
Informes sobre el tema "Collective heating"
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Nitz, Peter y Jürgen Fluch. Collection of available solar process heat related national and trans-national research and funding programs. IEA SHC Task 64, abril de 2021. http://dx.doi.org/10.18777/ieashc-task64-2021-0001.
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Within Task 64/IV Solar Process Heat, Subtask E Guideline to Market is aiming to support a wider penetration of solar thermal technologies in the supply of heating (and cooling) in industry, demonstrating Solar Heat for Industrial Processes (SHIP) to be an important contribution to the decarbonisation of the industrial sector. This requires not only to overcome technical and/or technological barriers, but it is crucial to also address on technical barriers. Whereas well suited system integration strategies, design tools, standardized procedures or modular components are all in all paramount for the development of reliable and prompt off the shelve solutions, experience shows that often non-technological barriers might have a critical role in the decision making process. Above all, competitiveness and investment/financing related barriers prove in many cases to be the bottleneck for the adoption of solar thermal technologies in the industrial framework.
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Dietiker, B., A. J.-M. Pugin, H. Crow, K. Brewer y H. A. J. Russell. Geophysical data interpretation for the York University ATES site investigation, Ontario. Natural Resources Canada/CMSS/Information Management, 2024. http://dx.doi.org/10.4095/332366.
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Aquifer Thermal Energy Storage (ATES) systems have the potential of reducing heating and cooling energy consumption at institutional and commercial scales. ATES systems are popular in Europe, particularly in areas of extensive glacial and post glacial unconsolidated sediment. Southern Ontario shares numerous similarities with such settings. To support an ATES study at York University, Toronto, Ontario, three geophysical datasets were collected i) Microtremor analysis (the horizontal-to-vertical spectral ratio technique, HVSR), ii) seismic reflection, and iii) borehole geophysics. The three techniques provide different scales and resolution of subsurface investigation and form a complementary suite of tools. In areas with thick sediment cover, depth to bedrock estimations often suffer from sparse data. The HVSR technique is a low cost, nonintrusive, rapid approach to estimating depth to bedrock. ATES systems commonly require enhanced information on the succession of surficial geological units, and aquifer geometry and heterogeneity. Seismic reflection data collection can provide insights into all these characteristics and consequently provide greatly enhanced target information for follow-up drilling. The confidence in seismic interpretation can be improved through collection of subsurface information from drilling, either through the combination of drill core logging (sedimentology), core testing, and downhole geophysics. Multiple downhole geophysical data were collected to support i) lithological characterisation (gamma, conductivity, magnetic susceptibility), ii) seismic velocity analysis (p and s-wave), and iii) hydrogeological characteristics (temperature, and porosity using nuclear magnetic resonance). Collectively, the geophysical data can be framed in a basin analysis methodology. This study shows that these surveys can reduce uncertainty - and potentially the cost - of mitigating a poorly understood geological context that could compromise the full potential of an ATES development.
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Holz, Ceecee. Are G20 countries doing their fair share of global climate mitigation?: Comparing ambition and fair shares assessments of G20 countries' nationally determined contributions (NDCs). Oxfam International, septiembre de 2023. http://dx.doi.org/10.21201/2023.621540.
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As the group of the world’s largest economies and biggest emitters, G20 countries are central to implementing solutions to the climate emergency. This discussion paper assesses to what extent they are setting climate mitigation targets that are ambitious enough and/or meet their fair share of global emissions reductions consistent with limiting global heating to 1.5°C. It applies three different methodologies to assess their pledges. Despite some differences between these methodologies, the paper finds that the G20 countries – both collectively, and almost all of them individually – are failing to achieve their fair share of ambitious global mitigation required to limit global heating to 1.5°C, regardless of which assessment methodology is applied. Additionally, the assessment shows that the high-income G20 member countries are pledging to do a much smaller fraction of their fair share as compared to the middle-income countries. The G7 countries among the G20, in particular, appear to now be focusing their attention on the increase of ambition of middle-income and low-income countries while not recognising the need to also substantially increase the ambition in their own 2030 pledges. Additionally, the G7 countries continue to fail to recognise the need to commit to individual long-term climate finance to low and middle-income countries, at a scale much higher than what they currently provide, to enable rapid and just transitions to climate-resilient and low-carbon societies powered by renewable energy. This analysis highlights that G20 countries must both urgently, and before COP28 in December 2023, raise the ambition of their pledges for action by 2030, ramp up their provision of international climate finance and increase their international cooperation and support.
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Eneroth, Hanna, Hanna Karlsson Potter y Elin Röös. Environmental impact of coffee, tea and cocoa – data collection for a consumer guide for plant-based foods. Department of Energy and Technology, Swedish University of Agricultural Sciences, 2022. http://dx.doi.org/10.54612/a.2n3m2d2pjl.
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In 2020, WWF launched a consumer guide on plant-based products targeting Swedish consumers. The development of the guide is described in a journal paper (Karlsson Potter & Röös, 2021) and the environmental impact of different plant based foods was published in a report (Karlsson Potter, Lundmark, & Röös, 2020). This report was prepared for WWF Sweden to provide scientific background information for complementing the consumer guide with information on coffee, tea and cocoa. This report includes quantitative estimations for several environmental categories (climate, land use, biodiversity and water use) of coffee (per L), tea (per L) and cocoa powder (per kg), building on the previously established methodology for the consumer guide. In addition, scenarios of consumption of coffee, tea and cocoa drink with milk/plant-based drinks and waste at household level, are presented. Tea, coffee and cacao beans have a lot in common. They are tropical perennial crops traditionally grown in the shade among other species, i.e. in agroforestry systems. Today, the production in intensive monocultures has negative impact on biodiversity. Re-introducing agroforestry practices may be part of the solution to improve biodiversity in these landscapes. Climate change will likely, due to changes in temperature, extreme weather events and increases in pests and disease, alter the areas where these crops can be grown in the future. A relatively high ratio of the global land used for coffee, tea and cocoa is certified according to sustainability standards, compared to other crops. Although research on the implications of voluntary standards on different outcomes is inconclusive, the literature supports that certifications have a role in incentivizing more sustainable farming. Coffee, tea and cocoa all contain caffeine and have a high content of bioactive compounds such as antioxidants, and they have all been associated with positive health outcomes. While there is a strong coffee culture in Sweden and coffee contributes substantially to the environmental impact of our diet, tea is a less consumed beverage. Cocoa powder is consumed as a beverage, but substantial amounts of our cocoa consumption is in the form of chocolate. Roasted ground coffee on the Swedish market had a climate impact of 4.0 kg CO2e per kg powder, while the climate impact of instant coffee powder was 11.5 kg CO2e per kg. Per litre, including the energy use for making the coffee, the total climate impact was estimated to 0.25 kg CO2e per L brewed coffee and 0.16 kg CO2e per L for instant coffee. Less green coffee beans are needed to produce the same amount of ready to drink coffee from instant coffee than from brewed coffee. Tea had a climate impact of approximately 6.3 kg CO2 e per kg dry leaves corresponding to an impact of 0.064 CO2e per L ready to drink tea. In the assessment of climate impact per cup, tea had the lowest impact with 0.013 kg CO2e, followed by black instant coffee (0.024 kg CO2e), black coffee (0.038 kg CO2e), and cocoa drink made with milk (0.33 kg CO2e). The climate impact of 1kg cocoa powder on the Swedish market was estimated to 2.8 kg CO2e. Adding milk to coffee or tea increases the climate impact substantially. The literature describes a high proportion of the total climate impact of coffee from the consumer stage due to the electricity used by the coffee machine. However, with the Nordic low-carbon energy mix, the brewing and heating of water and milk contributes to only a minor part of the climate impact of coffee. As in previous research, coffee also had a higher land use, water use and biodiversity impact than tea per L beverage. Another factor of interest at the consumer stage is the waste of prepared coffee. Waste of prepared coffee contributes to climate impact through the additional production costs and electricity for preparation, even though the latter was small in our calculations. The waste of coffee and tea at Summary household level is extensive and measures to reduce the amount of wasted coffee and tea could reduce the environmental impact of Swedish hot drink consumption. For the final evaluation of coffee and tea for the consumer guide, the boundary for the fruit and vegetable group was used. The functional unit for coffee and tea was 1 L prepared beverage without any added milk or sweetener. In the guide, the final evaluation of conventionally grown coffee is that it is ‘yellow’ (‘Consume sometimes’), and for organic produce, ‘light green’ (‘Please consume). The evaluation of conventionally grown tea is that it is ‘light green’, and for organic produce, ‘dark green’ (‘Preferably consume this’). For cocoa, the functional unit is 1 kg of cocoa powder and the boundary was taken from the protein group. The final evaluation of conventionally grown cocoa is that it is ‘orange’ (‘Be careful’), and for organically produced cocoa, ‘light green’.
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Hausner, Beatrix, Samira Karner, Hannah Tomasi y Azadeh Badieijaryani. Energy consulting: A tool for inclusion? Users TCP, 2023. http://dx.doi.org/10.47568/7xr134.
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This case study was conducted within the framework of the Austrian task participation IEA User-Centred Energy Systems Empowering all: Gender equality for the energy transition and analyzes to what extent the instrument of company-independent energy consulting in Austria addresses different target groups and takes gender and diversity aspects into account. Energy efficiency, climate neutrality in heating and electricity consumption are relevant aspects for the implementation of the energy transition. In addition, longer-term cost reduction for energy use is increasingly relevant for consumers and households. In Austria, therefore, company-independent energy consulting is offered and required renovations are partially subsidized (Stadt Wien, 2022). From a gender and diversity perspective, the following questions arise in this context: Who can take advantage of energy consulting? Who benefits from energy consulting? Are gender aspects, migration, age and socio-economic factors, as well as the overlaps of mentioned aspects (intersectionality) taken into account? What should be considered in gender and diversity friendly energy consulting? What could be a suitable approach for gender- and diversity-friendly energy consulting? In order to answer these questions, results of the international literature on the aspect of inclusion in energy consulting were first compiled, which were used for the development of the guideline for the data collection tools and for the data analysis. Based on this, internet research on the implementation of company-independent energy consulting and its funding opportunities in Austria was conducted. The unanswered questions about the systematics and processes of energy consulting were answered in a semi-structured expert interview with a person who conducts energy consulting. The case study is structured as follows: First, essential terms are explained. Then, the relevance of the case study for Austria as well as the international state of research are presented. This is followed by the results of the research and the interview along the guiding themes and the discussion of the results. Finally, the results are summarized, and recommendations are elaborated.