Littérature scientifique sur le sujet « Efficienza termica »
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Articles de revues sur le sujet "Efficienza termica"
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Li, Liu-Liu, Young-Joon Seo et Min-Ho Ha. « The efficiency of major container terminals in China : super-efficiency data envelopment analysis approach ». Maritime Business Review 6, no 2 (11 janvier 2021) : 173–87. http://dx.doi.org/10.1108/mabr-08-2020-0051.
Texte intégralRésumé :
Purpose Seaports are a signifier for the world economy and international trade. Notwithstanding the considerable role of Chinese ports in global trade, only few studies have explored the efficiency of Chinese container terminals. Furthermore, studies on Chinese port efficiency has typically centered on port-level analysis, not terminal level. Therefore, this study aims to examine the operation efficiency of Chinese container terminals. Design/methodology/approach This study uses super-efficiency data envelopment analysis (SE-DEA) approach. SE-DEA is superior than basic DEA model because it is feasible for categorizing and ranking the efficiency of container terminals more accurately and comprehensively. In the basic model, if the several decision-making units (DMUs) are efficient, the efficiency value of them is “1.” However, in the SE-DEA model, the most efficient DMU is over “1.” Based on the level of container throughput in 2018, the top 20 Chinese container terminal companies were selected. Various production quotas were selected as inputs, while the container throughput was considered output. Findings The findings show that Terminal Shanghai Mingdong Container Terminal Co., Ltd. was ranked 1, followed by Shanghai Shengdong International Container Terminal Co., Ltd., Shanghai International Port (Group) Co., Ltd. and Yidong Container Terminal Branch. Originality/value This study contributes to providing some insights into Chinese container terminal industry to augment the efficiency. This study also provides practical and policy implications (e.g. better terminal operations) for container terminals.
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Nagaraja, G., H. S. Rameshbabu et Gowrishankar Gowrishankar. « HERA : High-Efficiency Resource Allocation Scheme for Newly Joined Mobile Terminal in Heterogeneous Wireless Network ». Indian Journal Of Science And Technology 15, no 25 (5 juillet 2022) : 1244–52. http://dx.doi.org/10.17485/ijst/v15i25.713.
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Dumitrescu, C., R. Rădoi, C. Cristescu et L. Dumitrescu. « EXPERIMENTAL MODEL OF A COMBINED THERMAL SYSTEM FOR EFFICIENT USE OF RENEWABLE ENERGIES ». INMATEH Agricultural Engineering 60, no 1 (30 avril 2020) : 287–94. http://dx.doi.org/10.35633/inmateh-60-32.
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The article presents an experimental model of a modular structure system for the production of thermal energy and the results of conducting specific tests. The experimental model uses two renewable energy sources - solar energy and energy generated by burning biomass - to provide thermal energy for an increased duration, regardless of the atmospheric factors. Properly sized, the system can be designed as a series product, in a variety of powers, to be used by heat suppliers, and also by individuals, especially the ones from remote areas, who want to ensure their thermal energy independence by using renewable energy.
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Chen, Bo, Yang Bai, Zhengshan Yu, Tao Li, Xiaopeng Zheng, Qingfeng Dong, Liang Shen et al. « Efficient Semitransparent Perovskite Solar Cells for 23.0%-Efficiency Perovskite/Silicon Four-Terminal Tandem Cells ». Advanced Energy Materials 6, no 19 (19 juillet 2016) : 1601128. http://dx.doi.org/10.1002/aenm.201601128.
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Jeh, Jungwaun, Jungwoo Nam, Minseop Sim, Yulseong Kim et Youngran Shin. « A Study on the Efficiency Analysis of Global Terminal Operators Based on the Operation Characteristics ». Sustainability 14, no 1 (4 janvier 2022) : 536. http://dx.doi.org/10.3390/su14010536.
Texte intégralRésumé :
Shipping and port industries are undergoing rapid environmental changes because of the reorganization of carrier alliances, enlargement of ships, and an increase in global uncertainty. Thus, the sustainable operation of container terminals requires a new assessment of port efficiency and measures to enhance efficient operation. Hence, we classified 21 global terminal operators (GTOs) into stevedore, carrier, and hybrid GTOs based on their operation characteristics and derived a sustainable container terminal operation method using data envelopment analysis efficiency and Malmquist productivity index analysis. The results showed that stevedore GTOs exhibited improved efficiency when the terminal infrastructure was expanded. However, the returns to scale and technical change factors in the productivity change trend decreased. Meanwhile, the objective of carrier GTOs is cost reduction, unlike stevedore and hybrid GTOs, which focus on generating profits. Consequently, carrier GTOs were the most inefficient with little intention to improve efficiency. A systematic efficiency improvement strategy through the acquisition of a terminal share was effective for hybrid GTOs. However, similar to stevedore GTOs, investment in technical change was insufficient for hybrid GTOs. The efficiency analysis we conducted for each operation characteristic is expected to provide useful basic data for establishing efficiency improvement strategies for every GTO.
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Choi, Seokwoo Jake, Gi-Su Kim et BoKyung Kim. « Economic Efficiency of the Korean Container Terminals : A Stochastic Cost Frontier Approach ». Journal of Korea Trade 26, no 3 (30 mai 2022) : 23–44. http://dx.doi.org/10.35611/jkt.2022.26.3.23.
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Purpose - Recent issues such as vessel enlargement, strengthening of environmental regulations, and port smartization are expected to increase costs and intensify competition in the port industry. In the new normal era, when external growth has reached its limit, the efficient operation of ports is becoming indispensable for achieving sustainable growth. This study aims to identify the determinants of inefficiency by examining the cost structure and efficiency of container terminals in Korea and furthermore propose the political implications to derive the maximization of efficiency.
Design/methodology - This study estimates the cost function of container terminal operators and identifies the efficiency of container terminals using stochastic cost frontier (SCF) in the first stage. In the second step, the SCF results are compared with the data envelopment analysis (DEA). Last, this paper proposes efficiency determinants on container terminal operation to establish appropriate strategies. Out of the 29 container terminal operators in South Korea, 13 operators participated in the survey. The translog cost function was estimated utilizing a total of 116 observations collected over the 2007-2017 period.
Findings - Empirical analysis shows that economies of scale exist in Korea’s container ports, which provides a rationale for the government’s policy to establish the global terminal operator by integrating small terminal operators to enhance competitiveness. In addition, as a result of the determinants analysis, container throughput, weight of direct employment costs, and labour cost share have positive effects on improving cost efficiency, while inefficiency increases as the length of quay increases. More specifically, cost efficiency improves as the proportion of direct employment costs to outsourcing service costs increases.
Originality/value - This study contributes to analyzing the inefficiency factors of container terminals through efficiency analysis with respect to a cost function. In addition, this study proposes the practical and political implications, such as establishing a long-term manpower pool, the application of the hybrid liner terminal system, and the construction of a statistical data system, to improve the cost inefficiency of terminal operators.
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Zhang, Chunyang, Min Chen, Fan Fu, Hongwei Zhu, Thomas Feurer, Wenming Tian, Chao Zhu et al. « CNT-based bifacial perovskite solar cells toward highly efficient 4-terminal tandem photovoltaics ». Energy & ; Environmental Science 15, no 4 (2022) : 1536–44. http://dx.doi.org/10.1039/d1ee04008a.
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We describe highly efficient and stable bifacial perovskite solar cells incorporating carbon nanotube network films as a back contact enabling perovskite/CIS 4-terminal tandem solar cells to reach apower conversion efficiency of over 27%.
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Haberlag, Birte, Matthias Freytag, Constantin G. Daniliuc, Peter G. Jones et Matthias Tamm. « Efficient Metathesis of Terminal Alkynes ». Angewandte Chemie International Edition 51, no 52 (14 novembre 2012) : 13019–22. http://dx.doi.org/10.1002/anie.201207772.
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Gürel, Seyfettin, et Sezai Alper Tekin. « Bulk Switched DC-DC Buck Converter ». Energy, Environment and Storage 2, no 2 (17 mai 2022) : 31–40. http://dx.doi.org/10.52924/bcmq4493.
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This paper presents a buck converter which has an high efficient and low power consumption for low power applications. The proposed topology is based on buck converter using switching MOSFET with bulk-terminal. The suitable bulk-terminal switching voltage is selected by analyzing the effect of bulk voltage on a MOSFET performance. It is concluded that the bulk-switched DC-DC buck converter structure has the advantages such as high switching performance, low power consumption and high efficiency compared to conventional DC-DC converter circuits. The efficiency value has obtained 88.2%. The proposed circuit is approved experimentally and simultaneously
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Li, Wang, Zhu Xiaoning et Xie Zhengyu. « Efficient container stacking approach to improve handling : efficiency in Chinese rail–truck transshipment terminals ». SIMULATION 96, no 1 (16 avril 2019) : 3–15. http://dx.doi.org/10.1177/0037549719843347.
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An efficient container stacking approach is vital to the handling efficiency of container transshipment terminals. In this paper, by considering container allocation preferences and operation distance, the container stacking problem in rail–truck transshipment terminals has been formulated as a multi-objective optimization model to minimize container overlapping amounts and crane moving distance. A simulation-based algorithm implementing process has been developed to stack containers to the optimum positions. Computational experiments on data from a rail–truck transshipment terminal in China are conducted to test the efficiency of the proposed approach. Experimental results demonstrate that the container stacking approach is efficient and significant for improving handling efficiency in rail–truck transshipment terminals.
Thèses sur le sujet "Efficienza termica"
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Tomassoni, Elisa. « Studio analitico - sperimentale di involucri ad alta efficienza energetica in clima Mediterraneo ». Doctoral thesis, Università Politecnica delle Marche, 2014. http://hdl.handle.net/11566/242895.
Texte intégralRésumé :
La presente ricerca ha l’obiettivo di valutare analiticamente e sperimentalmente le presta
zioni di vari tipi di involucro in edifici residenziali ad alta efficienza energetica in clima Me
diterraneo, in termini di prestazione energetica, comfort termico e sostenibilità.
Gli edifici ad alta efficienza energetica sono oggetto di grande attenzione dato che le re
centi Direttive 2010/31/EU e 2012/27/EU introducono come obiettivo lo standard di e
dificio a energia quasi zero per le nuove costruzioni. Gli standard tedeschi della Passivhaus
rappresentano un valido modello da seguire per climi freddi mentre l’adozione di tale mo
dello nei climi Mediterranei determina problemi di surriscaldamento estivo. Le nuove Di
rettive hanno di recente sottolineato l’importanza di considerare il clima specifico ma lo
sviluppo di tecniche costruttive per involucri energeticamente efficienti adatte ad un clima
Mediterraneo rimane ancora una questione aperta.
L’obiettivo dello studio è dunque quello di verificare, analiticamente e sperimentalmente,
le prestazioni di involucri in legno super isolati, tipici del modello Passivhaus, in climi tem
perati con estati calde e di confrontarli con differenti tipologie di tecniche costruttive carat
terizzate da maggiore inerzia termica, comunemente adottate nell’area Mediterranea. Si
vuole inoltre valutare sperimentalmente e analiticamente il comportamento di una tecnica
mista individuata come possibile soluzione al problema del surriscaldamento estivo poiché
sul paramento interno dell’involucro leggero e superisolato in legno è stato adottato un
pannello di rivestimento massivo.
Il metodo adottato consiste in una strategia integrata tra monitoraggi e simulazioni cali
brate su dati sperimentali e ha riguardato l’analisi contemporanea di vari aspetti quali la pre
stazione energetica, il comfort e la sostenibilità economico ambientale secondo un approc
cio multidisciplinare. Lo studio è stato inoltre condotto attraverso l’utilizzo di differenti
metodi di valutazione per ogni aspetto analizzato e ha coinvolto una serie di analisi parame
triche per generalizzare i risultati a varie zone climatiche, modelli d’uso degli impianti e tec
niche di raffrescamento passivo.
In edifici residenziali ad alta efficienza energetica localizzati in clima Mediterraneo, dove
la prestazione termica estiva è una priorità, soluzioni leggere, pur avendo un minor impatto
ambientale, presentano problemi di surriscaldamento che possono essere risolti attraverso
l’adozione di opportune strategie passive, tra le quali l’aumento dell’inerzia termica sul lato
interno e la ventilazione notturna degli ambienti.This research is aimed at identifying, analytically and experimentally, the performance of several envelopes in high efficiency residential buildings under a Mediterranean climate, in terms of energy performance, thermal comfort and sustainability. The high efficiency buildings attract considerable attention since the recent Directives 2010/31/EU e 2012/27/EU set as an objective the standard of nearly zero energy building for new constructions. The German Passivhaus standards represent a good model to be followed in cold climates while the adoption of this model in Mediterranean climates caus es summer overheating problems. The new Directives recently highlighted the importance to consider the specific climate, however the development of constructive techniques for energy efficient envelopes suitable for a Mediterranean climate still remains an open question. Therefore the aim of the study is to verify, analytically and experimentally, the perfor mance of super insulated wooden envelopes, typical of the Passivhaus model, in hot summer temperate climates and to compare them with different types of construction techniques characterized by higher thermal inertia, commonly adopted in the Mediterrane an area. The aim is also to evaluate, experimentally and analytically, the behavior of a mixed weight technique identified as a possible solution to the summer overheating prob lem since on the inner side of the lightweight and super insulated wooden envelope, a mas sive panel was adopted. The method adopted set up an integrated strategy between monitoring and calibrated simulations on experimental data, and involved the simultaneous analysis of several aspects such as energy performance, comfort and environmental economic sustainability through a multidisciplinary approach. The study is also carried out through the adoption of different evaluation methods for each analyzed aspect and it involved a series of parametric analyses to generalize the results to various climate zones, use patterns of plants and passive cooling techniques. In high efficiency residential buildings located in a Mediterranean climate, where the summer thermal performance is a priority, lightweight solutions, even if they have a lower environmental impact, present overheating problems which can be solved through the adoption of appropriate passive strategies, such as the increase of the thermal inertia on the inner side and the night ventilation of the environments.
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SABATO, MASSIMO. « Analisi Termica di Moduli di Potenza per Veicoli a Trazione Ibrida ». Doctoral thesis, Università degli studi di Modena e Reggio Emilia, 2022. http://hdl.handle.net/11380/1277128.
Texte intégralRésumé :
Negli ultimi anni, i veicoli a trazione ibrida si stanno diffondendo in maniera sempre più estesa, rendendo più forte l’interesse dei ricercatori. Con ciò, componenti come motori elettrici, batterie, e convertitori di potenza sono stati interessati da significative innovazioni. Il presente lavoro di tesi di dottorato si focalizza principalmente sui convertitori di potenza, il cui scopo è quello di garantire la conversione di potenza da Corrente Alternata in Corrente Continua, e viceversa, per mezzo di semiconduttori come IGBT, DIODI e MOSFET. Nonostante i convertitori di potenza raggiungano tipicamente efficienze superiori al 90%, essi possono essere interessati da flussi termici nell’ordine di centinaia di W/cm^2.
Lo scopo principale di questa tesi di dottorato è quello di eseguire un’analisi termica dettagliata sui sistemi di conversione di potenza.
E’ stato sviluppato un tool di simulazione in grado di effettuare simulazioni di tipo elettro-termico (Banco Prova Virtuale). Questo strumento è in grado di valutare qualsiasi topologia di convertitore di potenza considerando un ampio range di condizioni operative. Inoltre, un elevato numero di moduli di potenza può essere esaminato con una potenza di calcolo limitata e bypassando test sperimentali. Tale strumento è in grado di identificare e scartare le configurazioni che presentano una bassa efficienza. In questo modo è possibile focalizzarsi solo sulle soluzioni più promettenti. In questo lavoro, il tool di simulazione è stato accuratamente validato con dati sperimentali e risultati di letteratura. Successivamente, è stata condotta una larga campagna di simulazione su diverse configurazioni di convertitori di potenza. Le prestazioni di tali dispositivi sono state valutate attraverso un accurato calcolo delle dissipazioni sia in condizioni stazionarie che dinamiche. Inoltre, è stato descritto in maniera dettagliata il comportamento dei signoli semiconduttori di potenza.
Per garantire prestazioni e affidabilità di tali dispositivi è necessario lo studio di un sistema di raffreddamento. Ci si è concentrati su una strategia di cooling a getti sommersi. Tutto lo studio è stato svolto con un approccio 3D-CFD. Inizialmente, la metodologia di calcolo è stata effettuata su una geometria semplificata che includeva un singolo getto, i cui risultati sono stati confrontati con un caso test sperimentale, ottenendo un’ottima correlazione. Di conseguenza, la metodologia di calcolo è stata adottata per effettuare un dettagliato studio parametrico. E’ stato valutato nel dettaglio l’effetto del diametro, dell’aspect ratio, della disposizione e del numero degli ugelli.
L’attività di ricerca ha permesso di comprendere in dettaglio il comportamento dei convertitori di potenza dal punto di vista elettro-termico. La progettazione del PC può essere fortemente supportata dal Banco Prova Virtuale sviluppato, infatti l’individuazione della migliore configurazione dei moduli di potenza è veloce ed accurata. I getti sommersi rappresentano un approccio di raffreddamento efficiente e flessibile per i semiconduttori e la potenza di pompaggio in gioco è piuttosto bassa.Over the last years, hybrid electric vehicles are becoming increasingly widespread attracting the interest of researchers in this field. Significant innovations have been recently achieved about components like electrical machines, energy storages, and power converters. Focusing on power converter, its function is to ensure the energy conversion from alternating current to direct current sides, and vice versa, by using power semiconductors as IGBTs, DIODEs, and MOSFETs. Despite power electronic devices are usually characterized by efficiencies over 90%, they can be characterized by heat flux densities in the order of hundreds of W/cm^2. The main purpose of the present PhD thesis is to perform a detailed thermal analysis on power conversion systems. An electro-thermal simulation tool (Virtual Test Bench) which can address the power converter design is developed and presented. The tool allows to evaluate any multilevel power converter topologies by covering a wide range of possible operating conditions. Moreover, many power module technologies can be evaluated at low computational cost and by avoiding costly laboratory tests. The proposed tool enables the anticipated identification of designs to be rejected because of their low efficiency. Therefore, the experimental efforts can be only focused on the most promising solutions. In the present work, the simulation tool is successfully validated against experiments and literature results. A large simulation campaign is then conducted by considering a number of power converter configurations. Their performance are evaluated by means an accurate power losses computation in both steady-state and time-dependent conditions. In addition, the behavior of single semiconductors equipping the power converter is detailedly investigated. Performance and reliability of such devices are ensured by means a dedicated cooling system. In the current work, only active cooling systems are taken into account. In detail, the focus is on design and application of submerged impinging jet cooling technique. A 3D-CFD simulation approach is adopted. The simulation methodology is firstly applied on a simplified geometry made by a single jet. For this geometry, results are compared to experimental test case obtaining a good overall correlation. Then, the validated 3D-CFD methodology is adopted to complete a detailed parametric study of jet cooling solution applied in power converters. The effect of nozzle diameter, aspect ratio, arrangement, and number of jets are accurately investigated. The research activity allows to understand in detail the power converter behavior from a thermal point of view. The power converter design process can be strongly supported by the developed Virtual Test Bench, in fact the individuation of the best power module configuration is fast and accurate. Moreover, the tool can be furthermore developed to allow a multi-objective optimization of power converter. Finally, submerged impinging jets represent an efficient and flexible cooling approach for semiconductors with low pumping power level.
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Marzari, Marica. « Utilizzo della modellazione energetica per ottimizzare le scelte progettuali di involucro. Il caso studio del nuovo centro residenziale a Pieve di Cento ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17554/.
Texte intégralRésumé :
Nel seguente elaborato di tesi è stata eseguita una lottizzazione nel Comune di Pieve di Cento (BO), sono stati scelte le stratigrafie delle componenti opache, i componenti vetrati gli impianti e le fonti rinnovabili in modo tale che tutte le unità immobiliari risultassero nZeb. E' quindi stato mostrato il procedimento che ha portato le diverse scelte progettuali eseguito su un software di simulazione energetica in condizioni semi-stazionarie, necessario per attribuire la classe energetica alle unità immobiliare, le quali sono risultate tutte in classe A4.
Successivamente con l'ausilio del software Design Builder è stato creato un modello dinamico, con lo scopo di valutare le condizioni delle u.i in relazione alle diverse temperature orarie; si sono così valutati i consumi durante la stagione invernale ed estiva per i tre edifici modellati, relazionandoli con l'energia prodotta dal fotovoltaico posto in copertura.
Con lo scopo di diminuire ulteriormente i consumi sono state proposte due diverse stratigrafie di pareti. E' stato creato un nuovo modello in condizioni semi-stazionarie per le due casistiche e si è osservato come i consumi diminuissero ulteriormente. A partire dal modello semi-stazionario si è individuata la stratigrafia più performante e si è implementata su Design Builder ciò ha permesso di valutare le diminuzioni in termini di consumi orari per i tre edifici.
Infine è stata definita la stratigrafia in grado di garantire un miglior comfort nella stagione estiva e si è dimostrato come essa riesca a far ridurre notevolmente il numero di giorni in cui è necessario che sia attivo l'impianto di raffrescamento.
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Zappalà, Federica. « Analisi dei risultati di risparmio energetico conseguiti a seguito della riqualificazione energetica della centrale termica di un condominio ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Trouver le texte intégralRésumé :
Alla base di questo elaborato vi è lo studio che ha portato alle scelte finali per le opere di riqualificazione energetica della centrale termica di un condominio sito a Bologna, seguito dall’elaborazione dei dati di consumo raccolti nel periodo successivo ai lavori. Lo studio di un caso specifico del genere ben si colloca in quella che è la situazione vigente oggi in Italia: infatti la problematica risiede non solo nei bassi standard energetici che erano a quei tempi sufficienti, ma anche nella degradazione a cui tali edifici sono andati incontro. Oggi queste condizioni non sono più sostenibili e dunque è necessario concentrarsi non solo sui target da raggiungere quando si costruisce, ma soprattutto su quelli da ottenere mediante delle riqualificazioni di edifici esistenti. Questo comporta il nascere di numerose problematiche che rendono più difficile operare sull’”esistente” poiché non poche sono le costrizioni e le limitazioni che implicano l’esclusione di alternative valide.La tesi si articola in cinque capitoli: il primo permette di contestualizzare il caso studio in quello che è il panorama nazionale in termini di normativa vigente. Il secondo capitolo mostra lo stato di fatto dell’impianto termico del condominio studiato mettendo in evidenza le principali criticità. È col terzo capitolo che inizia lo studio vero e proprio dell’intervento ottimale: vengono effettuati i calcoli necessari a un corretto dimensionamento dell’impianto di riscaldamento e dell’impianto di produzione di ACS. L’ulteriore passo consiste nella scelta dei singoli componenti della centrale termica che viene mostrata dettagliatamente nel capitolo 4; quando possibile vengono esposte le diverse opzioni applicabili e quindi confrontate al fine di compiere la scelta migliore. Il quinto capitolo, infine, esprimendosi in termini economici permette di analizzare le prestazioni dell’impianto dopo la riqualificazione e di confrontare i dati ottenuti con quanto era stato previsto prima dei lavori.
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FACCHINETTI, IRENE. « Thermally Regenerable Redox-Flow Batteries ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/308694.
Texte intégralRésumé :
Il calore a bassa temperatura (LTH), inferiore a 100°C, è una forma di energia largamente disponibile che viene dispersa nell’ambiente, senza alcun utilizzo. La conversione di questo tipo di energia in elettricità aprirebbe le porte allo sfruttamento di fonti energetiche come il calore solare, geotermico e di scarto industriale.
La conversione di LTH in elettricità non è però un processo efficiente a causa dei limiti posti dalla termodinamica, con la cosiddetta legge di Carnot, oltre che ai limiti tecnologici che riducono ulteriormente la conversione di questa forma di energia.
I dispositivi preposti per convertire LTH in elettricità devono poter operare con alte efficienze e potenze, e devono essere facilmente scalabili ed economici. Purtroppo, attualmente nessun dispositivo è in grado di effettuare questa conversione con potenze ed efficienze abbastanza elevate da giustificare gli alti costi (materiali, operazionali e manutenzione) e la complessità dei dispositivi stessi ed è per questo motivo che LTH non trova tutt’ora alcuna applicazione
Questo progetto di ricerca si è focalizzato sullo sviluppo di un dispositivo in grado di convertire LTH in maniera efficiente e con alte potenze. Tale dispositivo, chiamato Thermally Regnerable Redox-Flow Battery, TRB, è una batteria a flusso ricaricabile termicamente. Il dispositivo conta due diverse processi: la produzione energetica, che avviene in una cella elettrochimica in grado di produrre elettricità alle spese dell’energia libera di mescolamento di due soluzioni acquose dello stesso sale ma a diversa concentrazione. Quando le due soluzioni raggiungono la stessa concentrazione, la soluzione esausta viene mandata al secondo processo: un distillatore sottovuoto che rigenera il gradiente di concentrazione tra le due soluzioni sfruttando risorse di LTH. L’efficienza totale del dispositivo è quindi data dal prodotto tra l’efficienza della cella elettrochimica e l’efficienza del distillatore.
Studi termodinamici dimostrano che per incrementare tale efficienza è fondamentale lavorare sull’efficienza del distillatore, il cui valore dipende dalla scelta del soluto e del solvente. In particolare, per questo lavoro di ricerca si è scelto di operare con soluzioni acquose di NaI/I2 e LiBr/Br2.
I risultati raggiunti e le principali attività di ricerca vengono riportate brevemente in questo abstract:
Con la determinazione dei coefficienti di attività, si è calcolato l’energia libera di mescolamento e il potenziale a circuito aperto per entrambi i set di soluzioni (NaI e LiBr).
Le celle elettrochimiche sono state sviluppate specificamente per entrambi I sistemi studiati e test elettrochimici hanno permesso di valutare le performance dei due dispositivi, come potenza ed efficienza elettrochimica. La distillazione è stata modellizzata in modo da definire le condizioni ottimali di lavoro e determinare l’efficienza del processo.Low-Temperature Heat (LTH), below of 100°C, has elicited great interest among the scientific community, as a source of energy since it does not see any form of utilization as it is currently simply released into the environment. Its conversion would open the doors to the exploitation of a huge amount of energy as well, such as geothermal, solar, and industrial waste heat. The conversion efficiencies of LTH are low because of the limitations imposed by Carnot law, as well as the existence of technological limits which further reduce the efficiency of the conversion of LTH. In order to be suitable for extensive industrial production, LTH converters should show high power densities, scalable and efficient whilst being cost-effective; to this point, the devices proposed for this afore mentioned application all failed to achieve suitable efficiencies and power density, making the LTH conversion unfeasible. This PhD project was focused on the design of a device called Thermally Regenerable Redox-Flow Battery (TRB) consisting of a redox-flow battery that can be recharged by a thermal process. The device is based upon a two-stages technology composed by a “power production” stage and a “thermal” stage: power production happens in an electrochemical cell which release electricity at the expenses of the mixing free energy of two water solutions of the same salt at different concentrations, referred to as a concentration cell. When the two solutions reach the same concentration, the exhausted fluid is sent to the second stage, the thermal process, which regenerates the initial mixing free energy, by exploiting LTH sources, through vacuum distillation. The efficiency of the technology is the product between the efficiencies of the units in the device where both stages happen: the electrochemical cell, engineered for power production, and a distillation unit, designed to be responsible for thermal conversion. NaI/I2 and LiBr/Br2 water solutions will be the most discussed redox couple in this thesis, as result of thermodynamic analysis that have shown the importance related to the solvent and salt choice to ensure high energy conversion efficiencies. The achieved results, as well as the main research activities, are briefly reported here: starting from the determination of the activity coefficients, mixing free energy of the initial solutions, and the open circuit voltage of the electrochemical are calculated. Electrochemical cells are specifically designed for both systems while electrochemical tests are performed to evaluate the main performances of the devices, such as power density and electrochemical efficiency. Modeling of the operational conditions of the thermal stage allows to determine the distillation efficiency for both the solutions. The initial experiments prove an unprecedented heat-to-electricity efficiency for both the systems: 3% for TRB-NaI and 4-5% for TRB based on LiBr, depending on the thickness of the membrane with a power density output of almost 10 W m-2 for both technologies, which opens various possibilities to implement further improvements into this new class of energy storage/converter devices.
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Bucella, Teresa. « Sviluppo di un banco prova per la caratterizzazione sperimentale di un sistema di recupero termico basato su generatori termoelettrici ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
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L’attualità del settore tecnologico e le potenzialità dei generatori termoelettrici sono stati il punto di partenza per condurre un approfondimento mirato alla caratterizzazione sperimentale dei 6 moduli a base di bismuto di tellurio e di modello TEG2-126LDT. È stata effettuata un’analisi preliminare dei moduli in modo da comprendere al meglio condizioni operative, potenzialità, proprietà termoelettriche, parametri caratteristici e approfondire il principio di funzionamento della generazione termoelettrica.
Per la raccolta dei dati sperimentali è stato allestito un banco prova che si compone di una struttura di supporto, quattro elementi riscaldanti collegati in parallelo per simulare la sorgente di calore, due ventole per il raffreddamento ad aria e Arduino Mega 2560 come sistema di acquisizione delle misure di temperatura e tensione. Le misure di interesse sono state effettuate attraverso il modulo DC0-25V per la tensione generata da ogni modulo in regime di carico disaccoppiato e le termocoppie di tipo “K” per la misura delle temperature sul lato riscaldato e raffreddato del TEG. Il modello di TEG analizzato è impiegato nella conversione di calore alle basse temperature, cioè fino a 200°C a cui corrisponde una tensione a vuoto generata pari a 8.6 V.
Sulla base delle curve caratteristiche ottenute è stato calcolato il coefficiente di Seebeck. L’analisi sperimentale è stata approfondita a sua volta ricercando i parametri prestazionali, ossia il valore della figura di merito ZT e dell’efficienza di conversione del calore in potenza elettrica. I risultati ottenuti attestano le scarse efficienze raggiunte dai generatori termoelettrici che attualmente non presentano caratteristiche competitive nella sostituzione dei principali sistemi di produzione dell’energia.
Si è ipotizzato infine il funzionamento dei moduli nella condizione più favorevoli, cioè di massima generazione di tensione quando è applicata una differenza di temperatura pari a 170°C.
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Giusti, Francesca. « Fisica dell'accrescimento ». Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/12332/.
Texte intégralRésumé :
Un fenomeno astrofisico in grado di liberare una enorme quantità di energia, ben superiore a quella che scaturisce dalle reazioni di conversione di H in He nelle stelle, è l’accrescimento: esso si osserva nei più disparati ambienti astrofisici, dalle protostelle ai sistemi binari, dalle stelle di neutroni ai buchi neri. In questo elaborato cercherò di chiarire come avviene un processo di accrescimento, come può dar luogo ai dischi di accrescimento, come questi ultimi si formano nei sistemi binari, influenzando l’evoluzione delle stelle che li compongono, e infine come essi contribuiscono all’emissione di una Galassia Attiva.
Nel Capitolo 1 tratterò un particolare caso di accrescimento sferico, valido sotto precise condizioni, che in generale però non si riscontrano in ambienti astrofisici. Il modello, che fu teorizzato da Bondi, tuttavia è importante perché permette di capire in prima approssimazione che cosa è l’accrescimento e quali conseguenze può avere.
Nel Capitolo 2 discuterò come si ricava il limite di Eddington e perché sia così importante non solo per i processi di accrescimento.
Nel Capitolo 3 infine, dopo una breve introduzione qualitativa, volta a spiegare quali siano i principali responsabili del fenomeno dell’accrescimento in un disco in ambiente
astrofisico, mi concentrerò su due casi: i dischi di accrescimento in sistemi binari, dei quali spiegherò come e perché si formano, quali sono le quantità fisiche rilevanti che li caratterizzano e come influenzano l’evoluzione delle stelle che li compongono; i dischi di
accrescimento nelle Galassie Attive e il processo con cui essi emettono.
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Davidson, Gemma Rose. « N-terminal plasma profiling : high efficiency plasma proteomics ». Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569795.
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Blood is a highly accessible body fluid that is rich in biological information; it is widely accepted that this is the most popular diagnostic sample available within a clinical environment. The measurement of cellular and non-cellular blood components, including blood cells, electrolytes, metabolites, lipids and proteins can aid clinicians in establishing an individuals' health status and can also function to diagnose and monitor the progression of disease. An alteration in an individuals' physiological state, such as the presence/absence of disease, will often lead to an alteration in protein expression. The accurate identification and measurement of proteins found in the non-cellular component of blood, known as plasma, could provide key information relating to a multitude of biological processes. Blood plasma is considered to contain the most comprehensive proteome of the body, as it is in contact with every cell, tissue and organ. Enthused by the clinical potential of this biological fluid there has been a drive within the proteomics community to develop robust proteomic platforms for the analysis of the blood plasma proteome. Coupled with powerful technologies, such as chromatography and mass spectrometry, there has been some success. Initiatives, such as the human plasma proteome project (PPP) have strived to standardised and collate data across laboratories with the objective of the global analysis and quantification of the plasma proteins. Unfortunately, as yet the plasma proteome remains to a large degree undiscovered, or more suitably 'hidden'. Blood plasma contains many proteins from all parts of the body. Tensioned against these desirable features are two disadvantages that have thus far hindered most plasma proteomic studies: high complexity and large dynamic range. The quantitative dynamic range of the human plasma proteome spans over 10 orders of magnitude with a small number of high-abundance proteins dominating approximately 99% total protein concentration, with albumin alone constituting approximately 50% total plasma protein. The dominance of the plasma proteome by such high-abundance proteins has inhibited the ability of most proteomic studies to access those proteins considered low-abundance. This is especially problematic when one considers that those proteins that constitute approximately 1 % total plasma protein, such as tissue leakage proteins, are considered to be extremely important in protein biomarker discovery. The analytical challenges imposed by blood plasma have thus far hampered efforts to delve deep into the proteome; presently no analytical technique has been presented that can fully exploit the full potential of plasma for medicine and therapeutics. A reduction in analyte complexity and improvements in analytical instrumentation are the most common approaches to combat the complexity and dynamic range problems associated with the study of the plasma proteome. Although the selective removal of high-abundance proteins via immunodepletion is an attractive approach to address the dynamic range issue, many of the high-abundance plasma proteins, such as albumin, have been shown to associate with other proteins. Thus, selective depletion will lead to the non-specific removal of other proteins. Other strategies aim to selectively target specific amino acid residues for enrichment, however utilising such an approach might lead to the over or under-representation of certain proteins. A positional proteomics approach targets one of two locations common to all proteins; the N- terminus or the C-terminus. This investigation focuses on the adoption of a positional proteomics strategy to selectively enrich the N-terminal peptides of the human plasma proteins. A reduction in sample complexity is observed when compared to a traditional 'shot-gun' proteomic approach. The absolute measurement of proteins is particularly important for protein biomarker validation/verification and for the development of our own understanding of biological processes. The development ofa QconCAT protein that is a concatomer ofN-terminal peptides, each a surrogate for its parent plasma protein, has the potential to provide absolute measurement of N-terminal peptides in a multiplexed manner. Utilising highly sensitive and selective mass spectrometric techniques such as selected reaction monitoring (SRM) in combination with the N-terminal enrichment strategy and QconCAT technology there is potential to selectively target and quantify N- terminal peptides in a high-throughput manner. Utilising N-terminal enrichment as a tool for human plasma proteome analysis gives an insight into the magnitude of enzymatic processes that specifically target the N-terminal portion of a protein. Such exo- and endo- proteolytic activity could prove significant for biomarker research. Although dynamic range is still a major problem, the N-terminal enrichment strategy demonstrates its utility as a tool for profiling the human plasma N-terminome. The global analysis of the plasma proteome will most likely require a combination of proteomic approaches that will specifically target and enrich sub-sections of this unique proteome.
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Taylor, Robin. « Airport access and travel time uncertainty ». Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/7336.
Texte intégralRésumé :
The implications of travel time uncertainty on the operational efficiency of airport terminals have until now not been examined. With the forecast growth in congestion levels predicted for all modes of transport, not only will travel time uncertainty increase but its impact may increase also. The first part of this thesis covers the analysis of two passenger surveys conducted at Manchester Airport and Birmingham Airport. These surveys had the objective of providing evidence to support or dispute the belief that air travellers react to travel time uncertainty. The research identifies that passengers do react by allowing margins of safety for their access journeys, and that this change in behaviour will modify the arrival distribution patterns at airports. The second part of this thesis examines how airport passenger flows could be altered by a change in the arrival distribution of originating passengers at airport terminals. Three airports - Manchester, Birmingham and East Midlands International - are modelled using a simulation tool and tested to assess how a shift in arrival distribution affects queuing and peak passenger volumes within the airport terminal. The findings of this thesis show that airport passenger terminal operational efficiency is affected by access journey time uncertainty. It also identifies that passenger decision making can only be explained by various combinations of factors. Possible methods of minimising the effects of travel time uncertainty are considered. The advantages and disadvantages of access journey time uncertainty for airports and airlines are discussed. It concludes that, to be successful in overcoming negative aspects, both parties must provide a service that results in customer satisfaction. This is the only sure way to maintain their respective revenue levels and secure their future in what is becoming an increasingly competitive industry.
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Domeniconi, Lorenzo. « Tecnologie elettroniche per case ad elevata efficienza energetica ». Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15538/.
Texte intégralRésumé :
L'elaborato parla delle nuove tecnologie per la costruzione di edifici ad elevata efficienza energetica, con tutte le caratteristiche e restrizioni per poter rientrare nella classe passivhaus.
In particolare, si approfondiscono gli argomenti riguardanti i pannelli fotovoltaici e termici, il sistema di ventilazione meccanica controllata e il sistema geotermico.
All'interno è presente anche un confronto tra un impianto fotovoltaico ibrido e stand alone, per dimostrare il fatto che ancora è sconveniente realizzare impianti completamente distaccati dalla rete elettrica nazionale.
Livres sur le sujet "Efficienza termica"
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A witness account of the rise and fall of the NHS : From its lean and efficient, noble beginning to its middle-age spread, its present near-terminal obese state and the flawed attempts at resuscitation. Aylesbury, Buckinghamshire, England : ShieldCrest, 2012.
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Court, Jane, Sue Hides et John Webb-Ware, dir. Sheep Farming for Meat and Wool. CSIRO Publishing, 2010. http://dx.doi.org/10.1071/9780643101333.
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Sheep Farming for Meat and Wool contains practical, up-to-date information on sheep production and management for producers throughout temperate Australia. It is based on research and extension projects conducted over many years by the Department of Primary Industries and its predecessors and the University of Melbourne.
The book covers business management, pasture growth and management, nutrition and feed management, drought management, reproductive management, disease management, genetic improvement, animal welfare and working dog health. It also gives seasonal reminders for a spring lambing wool-producing flock, for autumn lambing Merino ewes joined to Border Leicester rams, and for winter lambing crossbred ewes joined to terminal sires. It will guide new and established farmers, students of agriculture and service providers with detailed information on the why and how of sheep production, and will assist farmer groups to initiate activities aimed at increasing their efficiency in specific areas of sheep production.
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10 airport survey : Energy use, policies, and programs for terminal buildings : a report to the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. Lakewood, CO : Clean Airport Partnership, 2003.
Trouver le texte intégralChapitres de livres sur le sujet "Efficienza termica"
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Demirel, Baris, Kevin Cullinane et Hercules Haralambides. « Container Terminal Efficiency and Private Sector Participation ». Dans The Blackwell Companion to Maritime Economics, 571–98. Oxford, UK : Wiley-Blackwell, 2012. http://dx.doi.org/10.1002/9781444345667.ch28.
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Wang, Wei, Chuang Zhang, Xiaoli Zheng et Yuxuan Du. « Analysis of the Micro Implicit Feedback Behavior of User Network Exploring Based on Mobile Intelligent Terminal ». Dans Proceeding of 2021 International Conference on Wireless Communications, Networking and Applications, 28–39. Singapore : Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2456-9_4.
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AbstractIn the face of the information recommendation requirements in mobile Internet applications, in order to better use the user micro implicit feedback behavior obtained by the mobile intelligent terminal to improve the recommendation efficiency, this paper intends to carry out the analysis of the implicit feedback behavior by analyzing the behavior distribution and behavior correlation. The analytical results reveal the particularity of the implicit feedback behavior in mobile intelligent terminal.
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Chen, Danny Z., et Xiaodong Wu. « Efficient Algorithms for k-Terminal Cuts on Planar Graphs ». Dans Algorithms and Computation, 332–44. Berlin, Heidelberg : Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/3-540-45678-3_29.
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Fang, Qin, et Hao Wu. « Efficient Decoupled Analytical/Numerical Approach of Terminal Ballistic Trajectory ». Dans Concrete Structures Under Projectile Impact, 211–54. Singapore : Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-3620-0_6.
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Grimm, Carsten. « Efficient Farthest-Point Queries in Two-terminal Series-parallel Networks ». Dans Graph-Theoretic Concepts in Computer Science, 122–37. Berlin, Heidelberg : Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-53174-7_10.
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Hayashi, Koichiro, Sylvia Chen, Paul Opare-Addo et Ashok Khatri. « An Efficient Approach to Synthesize Multiple Peptides with Carboxyl C-termini ». Dans Advances in Experimental Medicine and Biology, 177–78. New York, NY : Springer New York, 2009. http://dx.doi.org/10.1007/978-0-387-73657-0_81.
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Wu, Di, Xing Li, Yongmei Sun, Yuefeng Ji, Jie Mao et Yingting Liu. « A Highly Efficient Indoor Localization Scheme Based Only on Mobile Terminal ». Dans Trustworthy Computing and Services, 161–68. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-43908-1_21.
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Schaack, J., et T. Shenk. « Adenovirus Terminal Protein Mediates Efficient and Timely Activation of Viral Transcription ». Dans Transforming Proteins of DNA Tumor Viruses, 185–90. Berlin, Heidelberg : Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74578-2_23.
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Shi, Yingjie, Xiang Wang, Wei Wang, Huayun Zhang et Shusong Jiang. « Implementation and Application of Embedded Real-Time Database for New Power Intelligent Terminal ». Dans Proceeding of 2021 International Conference on Wireless Communications, Networking and Applications, 711–20. Singapore : Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2456-9_72.
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AbstractAn implementation method of embedded real-time database is proposed. The lightweight high matching of power model is realized through tree structure. The resource consumption of real-time database in embedded device environment is reduced by means of separated storage and non independent process deployment. The efficient access of measuring point data is realized through internal mapping rules and improved breadth first search algorithm. Experiments show that the embedded real-time database realized by this method has good performance and low energy consumption, and is suitable for intelligent terminal equipment in new power system.
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Turna, Özgür Can, Muhammed Ali Aydin et Tülin Atmaca. « A Dynamic Energy Efficient Optical Line Terminal Design for Optical Access Network ». Dans Computer Networks, 260–69. Cham : Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-19419-6_25.
Texte intégralActes de conférences sur le sujet "Efficienza termica"
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Postnov, Sergey. « Optimal damping problem with additional terminal state condition in diffusion-wave processes ». Dans 2020 2nd International Conference on Control Systems, Mathematical Modeling, Automation and Energy Efficiency (SUMMA). IEEE, 2020. http://dx.doi.org/10.1109/summa50634.2020.9280617.
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Bastos, J., J. Rodriguez et C. Verikoukis. « Mobile terminal interfaces management for energy efficiency ». Dans 2012 IEEE 17th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD). IEEE, 2012. http://dx.doi.org/10.1109/camad.2012.6335309.
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Liu, Yin, Yingxin Xie, Fengyu Wang, Chen Fang et Ting Lei. « An Efficiency Management Terminal Considering Demand Response ». Dans 2015 International Conference on Computer Science and Intelligent Communication. Paris, France : Atlantis Press, 2015. http://dx.doi.org/10.2991/csic-15.2015.96.
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Korotky, S. K., et A. Azizi. « Efficient Clock Distribution in a High-Speed Time-Multiplexed-Switched Optical Network ». Dans Photonic Switching. Washington, D.C. : Optica Publishing Group, 1989. http://dx.doi.org/10.1364/phs.1989.tds208.
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We demonstrate an efficient method for clock distribution in time-multiplexed-switched optical local area networks. The local clock of a 4 Gb/s terminal on an experimental network is synchronized to the switch master clock located 5 km from the terminal.
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Tao Li et Aiqun Hu. « Efficient transitive trust model for mobile terminal ». Dans 2012 7th International ICST Conference on Communications and Networking in China (CHINACOM 2012). IEEE, 2012. http://dx.doi.org/10.1109/chinacom.2012.6417482.
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Galaviz-Schomisch, Ruth, John Gulding et Zhihao Zou. « Measuring Terminal Arrival Efficiency Rates using Individual Runways ». Dans 16th AIAA Aviation Technology, Integration, and Operations Conference. Reston, Virginia : American Institute of Aeronautics and Astronautics, 2016. http://dx.doi.org/10.2514/6.2016-4220.
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Qiong Li, Qinglin Meng et Lihua Zhao. « Energy efficiency design of an airport terminal building ». Dans 2010 International Conference on Advances in Energy Engineering (ICAEE). IEEE, 2010. http://dx.doi.org/10.1109/icaee.2010.5557567.
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Zhang Limin et Qi Deyu. « Energy-efficient task scheduling algorithm for mobile terminal ». Dans IET International Conference on Wireless Mobile and Multimedia Networks Proceedings (ICWMMN 2006). IEE, 2006. http://dx.doi.org/10.1049/cp:20061317.
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Frateschi, Newton C., Hanmin Zhao, James J. Elliot, Sabeur Siala, M. Govindarajan, Richard N. Nottenburg et Paul D. Dapkus. « High-efficiency three-terminal laser array for optical interconnect ». Dans OE/LASE'93 : Optics, Electro-Optics, & Laser Applications in Science& Engineering, sous la direction de Daniel Renner. SPIE, 1993. http://dx.doi.org/10.1117/12.146915.
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Khoueiry, Boulos Wadih, et M. Reza Soleymani. « Improving the Bandwidth Efficiency of Multi-Terminal Satellite Communications ». Dans 2015 IEEE International Conference on Ubiquitous Wireless Broadband (ICUWB). IEEE, 2015. http://dx.doi.org/10.1109/icuwb.2015.7324464.
Texte intégralRapports d'organisations sur le sujet "Efficienza termica"
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Flaishman, Moshe, Herb Aldwinckle, Shulamit Manulis et Mickael Malnoy. Efficient screening of antibacterial genes by juvenile phase free technology for developing resistance to fire blight in pear and apple trees. United States Department of Agriculture, décembre 2008. http://dx.doi.org/10.32747/2008.7613881.bard.
Texte intégralRésumé :
Objectives: The original objectives of this project were to: Produce juvenile-free pear and apple plants and examine their sensitivity to E. amylovora; Design novel vectors, for antibacterial proteins and promoters expression, combined with the antisense TFL1 gene, and transformation of Spadona pear in Israel and Galaxy apple in USA. The original objectives were revised from the development of novel vectors with antibacterial proteins combined with the TFL-1 due to the inefficiency of alternative markes initially evaluated in pear, phoshomannose-isomerase and 2-deoxyglucose-6-phosphate phosphatase and the lack of development of double selection system. The objectives of project were revised to focus primarily on the development additional juvenile free systems by the use of another pear variety and manipulation of the FT gene under the control of several promoters. Based on the results creation of fire blight resistance pear variety was developed by the use of the juvenile free transgenic plant. Background: Young tree seedlings are unable to initiate reproductive organs and require a long period of shoot maturation, known as juvenile phase. In pear, juvenile period can last 5-7 years and it causes a major delay in breeding programs. We isolated the TFL1 gene from Spadona pear (PcTFL1-1) and produced transgenic ‘Spadona’ trees silencing the PcTFL1 gene using a RNAi approach. Transgenic tissue culture ‘Spadona’ pear flowered in vitro. As expected, the expression of the endogenous PcTFL1 was suppressed in the transgenic line that showed precocious flowering. Transgenic plants were successfully rooted in the greenhouse and most of the plants flowered after only 4-8 months, whereas the non-transformed control plants have flowered only after 5-6 years of development. Major achievements: Prior to flower induction, transgenic TFL1-RNAi ‘Spadona’ plants developed a few branches and leaves. Flower production in the small trees suppressed the development of the vegetative branches, thus resulting in compact flowering trees. Flowering was initiated in terminal buds, as described for the Arabidopsis tfl1 mutant. Propagation of the transgenic TFL1-RNAi ‘Spadona’ was performed by bud grafting on 'Betulifolia' rootstock and resulted in compact flowering trees. The transgenic flowering grafted plants were grown in the greenhouse under a long photoperiod for one year, and flowered continuously. Pollination of the transgenic flowers with ‘Costia‘ pear pollen generated fruits of regular shape with fertile F1 seeds. The F1 transgenic seedling grown in the greenhouse formed shoots and produced terminal flowers only five months after germination. In addition, grafted F1 transgenic buds flower and fruit continuously, generating hybrid fruits with regular shape, color and taste. Several pear varieties were pollinated with the transgenic TFL1-RNAi ‘Spadona’ pollen including `Herald Harw` that was reported to have resistance to fire blight diseases. The F-1 hybrid seedlings currently grow in our greenhouse. We conclude that the juvenile-free transgenic ‘Spadona’ pear enables the development of a fast breeding method in pear that will enable us to generate a resistance pear to fire blight. Implications: The research supported by this grant has demonstrated the use of transgenic juvenile free technology in pear. The use of the juvenile free technology for enhancement of conventional breeding in fruit tree will serve to enhance fast breeding systems in pear and another fruit trees.
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Mawassi, Munir, Adib Rowhani, Deborah A. Golino, Avichai Perl et Edna Tanne. Rugose Wood Disease of Grapevine, Etiology and Virus Resistance in Transgenic Vines. United States Department of Agriculture, novembre 2003. http://dx.doi.org/10.32747/2003.7586477.bard.
Texte intégralRésumé :
Rugose wood is a complex disease of grapevines, which occurs in all growing areas. The disease is spread in the field by vector transmission (mealybugs). At least five elongated-phloem- limited viruses are implicated in the various rugose wood disorders. The most fully characterized of these are Grapevine virus A (GV A) and GVB, members of a newly established genus, the vitivirus. GVC, a putative vitivirus, is much less well characterized than GV A or GVB. The information regarding the role of GVC in the etiology and epidemiology of rugose wood is fragmentary and no sequence data for GVC are available. The proposed research is aimed to study the etiology and epidemiology of rugose wood disease, and to construct genetically engineered virus-resistant grapevines. The objectives of our proposed research were to construct transgenic plants with coat protein gene sequences designed to induce post-transcriptional gene silencing (pTGS); to study the epidemiology and etiology of rugose wood disease by cloning and sequencing of GVC; and surveying of rugose wood- associated viruses in Californian and Israeli vineyards. In an attempt to experimentally define the role of the various genes of GV A, we utilized the infectious clone, inserted mutations in every ORF, and studied the effect on viral replication, gene expression, symptoms and viral movement. We explored the production of viral RNAs in a GV A-infected Nicotiana benthamiana herbaceous host, and characterized one nested set of three 5'-terminal sgRNAs of 5.1, 5.5 and 6.0 kb, and another, of three 3'-terminal sgRNAs of 2.2, 1.8 and 1.0 kb that could serve for expression of ORFs 2-3, respectively. Several GV A constructs have been assembled into pCAMBIA 230 I, a binary vector which is used for Angrobacterium mediated transformation: GV A CP gene; two copies of the GV A CP gene arranged in the same antisense orientation; two copies of the GV A CP gene in which the downstream copy is in an antigens orientation; GV A replicase gene; GV A replicase gene plus the 3' UTR sequence; and the full genome of GV A. Experiments for transformation of N. benthamiana and grapevine cell suspension with these constructs have been initiated. Transgenic N. benthamiana plants that contained the CP gene, the replicase gene and the entire genome of GV A were obtained. For grapevine transformation, we have developed efficient protocols for transformation and successfully grapevine plantlets that contained the CP gene and the replicase genes of GV A were obtained. These plants are still under examination for expression of the trans genes. The construction of transgenic plants with GV A sequences will provide, in the long run, a means to control one of the most prevalent viruses associated with grapevines. Our many attempts to produce a cDNA library from the genome of GVC failed. For surveying of rugose wood associated viruses in California vineyards, samples were collected from different grape growing areas and tested by RT-PCR for GV A, GVB and GVD. The results indicated that some of the samples were infected with multiple viruses, but overall, we found higher incidence of GVB and GV A infection in California vineyards and new introduction varieties, respectively. In this research we also conducted studies to increase our understanding of virus - induced rootstock decline and its importance in vineyard productivity. Our results provided supporting evidence that the rootstock response to virus infection depends on the rootstock genotype and the virus type. In general, rootstocks are differ widely in virus susceptibility. Our data indicated that a virus type or its combination with other viruses was responsible in virus-induced rootstock decline. As the results showed, the growth of the rootstocks were severely affected when the combination of more than one virus was present.
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Ehrlich, Marcelo, John S. Parker et Terence S. Dermody. Development of a Plasmid-Based Reverse Genetics System for the Bluetongue and Epizootic Hemorrhagic Disease Viruses to Allow a Comparative Characterization of the Function of the NS3 Viroporin in Viral Egress. United States Department of Agriculture, septembre 2013. http://dx.doi.org/10.32747/2013.7699840.bard.
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Project Title: "Development of a plasmid-based reverse genetics system for the Bluetongue and Epizootic Hemorrhagic Disease viruses to allow comparative characterization of the function of the NS3 viroporin in viral egress". Project details: No - IS-4192-09; Participants – Ehrlich M. (Tel Aviv University), Parker J.S. (Cornell University), DermodyT.S. (Vanderbilt University); Period - 2009-2013. Orbiviruses are insect-borne infectious agents of ruminants that cause diseases with considerable economical impact in Israel and the United States. The recent outbreaks of BTV in Europe and of Epizootic Hemorrhagic Disease Virus (EHDV) in Israel, underscore the need for: (i) a better comprehension of the infection process of orbiviruses, (ii) the identification of unique vs. common traits among different orbiviruses, (iii) the development of novel diagnosis and treatment techniques and approaches; all aimed at the achievement of more effective control and treatment measures. It is the context of these broad goals that the present project was carried out. To fulfill our long-term goal of identifying specific viral determinants of virulence, growth, and transmission of the orbiviruses, we proposed to: (i) develop reverse genetics systems for BTV and EHDV2-Ibaraki; and (ii) identify the molecular determinants of the NS3 nonstructural protein related to viroporin/viral egress activities. The first objective was pursued with a two-pronged approach: (i) development of a plasmid-based reverse genetics system for BTV-17, and (ii) development of an "in-vitro" transcription-based reverse genetics system for EHDV2-Ibaraki. Both approaches encountered technical problems that hampered their achievement. However, dissection of the possible causes of the failure to achieve viral spread of EHDV2-Ibaraki, following the transfection of in-vitro transcribed genomic segments of the virus, revealed a novel characteristic of EHDV2-Ibaraki infection: an uncharacteristically low fold increase in titer upon infection of different cell models. To address the function and regulation of NS3 we employed the following approaches: (i) development (together with Anima Cell Metrology) of a novel technique (based on the transfection of fluorescently-labeledtRNAs) that allows for the detection of the levels of synthesis of individual viral proteins (i.e. NS3) in single cells; (ii) development of a siRNA-mediated knockdown approach for the reduction in levels of expression of NS3 in EHDV2-Ibaraki infected cells; (iii) biochemical and microscopy-based analysis of the localization, levels and post-translational modifications of NS3 in infected cells. In addition, we identified the altered regulation and spatial compartmentalization of protein synthesis in cells infected with EHDV2-Ibaraki or the mammalian reovirus. In EHDV2-Ibaraki-infected cells such altered regulation in protein synthesis occurs in the context of a cell stress reponse that includes the induction of apoptosis, autophagy and activation of the stressrelated kinase c-Jun N-terminal Kinase (JNK). Interestingly, inhibition of such stress-related cellular processes diminishes the production of infectious virions, suggesting that EHDV usurps these responses for the benefit of efficient infection. Taken together, while the present project fell short of the generation of novel reverse genetics systems for orbiviruses, the development of novel experimental approaches and techniques, and their employment in the analysis of EHDV-infected cells, yielded novel insights in the interactions of orbiviruses with mammalian cells.
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Rafaeli, Ada, Russell Jurenka et Chris Sander. Molecular characterisation of PBAN-receptors : a basis for the development and screening of antagonists against Pheromone biosynthesis in moth pest species. United States Department of Agriculture, janvier 2008. http://dx.doi.org/10.32747/2008.7695862.bard.
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The original objectives of the approved proposal included: (a) The determination of species- and tissue-specificity of the PBAN-R; (b) the elucidation of the role of juvenile hormone in gene regulation of the PBAN-R; (c) the identificationof the ligand binding domains in the PBAN-R and (d) the development of efficient screening assays in order to screen potential antagonists that will block the PBAN-R. Background to the topic: Moths constitute one of the major groups of pest insects in agriculture and their reproductive behavior is dependent on chemical communication. Sex-pheromone blends are utilised by a variety of moth species to attract conspecific mates. In most of the moth species sex-pheromone biosynthesis is under circadian control by the neurohormone, PBAN (pheromone-biosynthesis-activating neuropeptide). In order to devise ideal strategies for mating disruption/prevention, we proposed to study the interactions between PBAN and its membrane-bound receptor in order to devise potential antagonists. Major conclusions: Within the framework of the planned objectives we have confirmed the similarities between the two Helicoverpa species: armigera and zea. Receptor sequences of the two Helicoverpa spp. are 98% identical with most changes taking place in the C-terminal. Our findings indicate that PBAN or PBAN-like receptors are also present in the neural tissues and may represent a neurotransmitter-like function for PBAN-like peptides. Surprisingly the gene encoding the PBAN-receptor was also present in the male homologous tissue, but it is absent at the protein level. The presence of the receptor (at the gene- and protein-levels), and the subsequent pheromonotropic activity are age-dependent and up-regulated by Juvenile Hormone in pharate females but down-regulated by Juvenile Hormone in adult females. Lower levels of pheromonotropic activity were observed when challenged with pyrokinin-like peptides than with HezPBAN as ligand. A model of the 3D structure of the receptor was created using the X-ray structure of rhodopsin as a template after sequence alignment of the HezPBAN-R with several other GPCRs and computer simulated docking with the model predicted putative binding sites. Using in silico mutagenesis the predicted docking model was validated with experimental data obtained from expressed chimera receptors in Sf9 cells created by exchanging between the three extracellular loops of the HezPBAN-R and the Drosophila Pyrokinin-R (CG9918). The chimera receptors also indicated that the 3ʳᵈ extracellular loop is important for recognition of PBAN or Diapause hormone ligands. Implications: The project has successfully completed all the objectives and we are now in a position to be able to design and screen potential antagonists for pheromone production. The successful docking simulation-experiments encourage the use of in silico experiments for initial (high-throughput) screening of potential antagonists. However, the differential responses between the expressed receptor (Sf9 cells) and the endogenous receptor (pheromone glands) emphasize the importance of assaying lead compounds using several alternative bioassays (at the cellular, tissue and organism levels). The surprising discovery of the presence of the gene encoding the PBAN-R in the male homologous tissue, but its absence at the protein level, launches opportunities for studying molecular regulation pathways and the evolution of these GPCRs. Overall this research will advance research towards the goal of finding antagonists for this important class of receptors that might encompass a variety of essential insect functions.