• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 30
  • 8
  • 5
  • 5
  • 4
  • 4
  • 1
  • 1
  • Tagged with
  • 73
  • 13
  • 8
  • 8
  • 7
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Brandskyddsegenskaper, miljöpåverkan och hållbarhet med högtrycks vattendimsprinklers jämfört med traditionella sprinklers : En undersökning av högtrycks vattendimsprinklers jämfört traditionella sprinklers från brandsäkerhets-, miljö- och hållbarhetsperspektiv / Fire protection properties, environmental impact, and sustainability of high-pressure water mist sprinklers compared to traditional sprinklers : A study of high-pressure water mist sprinklers compared to traditional sprinklers, from fire safety, environmental, and sustainability perspective

Naserallah, Dina January 2023 (has links)
I denna studie har det utforskats skillnader mellan två olika typer av brandsläckningssystem:traditionella vattensprinklersystem och högtrycksvattendimma med avseende påbrandskyddsegenskaper samt miljö och hållbarhetsaspekterna. Syftet med denna studie är attförbättra förståelsen av de två olika systemen och dess användning för brandbekämpning.Traditionella vattensprinklersystem visade sig erbjuda effektiv branddetektion och respons tackvare värmekänsliga glasbulber och var särskilt effektiva i stora öppna utrymmen. Dessutomframstod dessa två vattensprinklersystemen som mycket lämpliga för miljöer med hög fibrositetsom till exempel sågverk.Högtrycksvattendimma erbjuder flera fördelar, såsom tidig branddetektion och respons, samt enmer effektiv brandsläckningsförmåga. Systemet använder små vattendroppar som avges medhögt tryck, vilket skapar en större täckningsyta och leder till upp till 90% mindrevattenanvändning. Detta minskar risken för vattenskador och gör systemet särskilt lämpligt föranvändning i trånga utrymmen och för skydd av objekt som Li-jonbatterier, samt i de flestaandra miljöer med undantag för dem där material med hög fibrositet förekommer.Miljömässigt visade sig vattendimma vara överlägsen utifrån flera olika aspekter. Det gällermindre vattenanvändning vilket därmed leder till mindre miljöfarligt brandvatten som behöverhanteras efter brandsläckning. Det uppnås även högre energieffektivitet och därmed lägrekoldioxidutsläpp på grund av att pumpen inte behöver hantera lika mycket vatten som med etttraditionellt sprinklersystem. Högtrycksvattendimma bidrar även till förbättrad luftkvalitet föratt den fokuserar på att bekämpa de farliga brandgaserna.Sammanfattningsvis har denna studie bidragit med viktiga insikter och analytiska slutsatser,som erbjuder en förstärkt förståelse av de jämförda brandskyddssystemen. Analyserna påvisaratt både högtrycksvattendimma och traditionella vattensprinklersystem har sina specifikafördelar beroende på deras tillämpningsområden. Syftet med studien var att undersöka ochjämföra dessa två system med avseende på deras brandbekämpningsförmåga för att bidra till enmer effektiv och optimerad brandbekämpning. Det har bristat med information från tidigarestudier vilket gör ämnet väldigt intressant att undersöka mer för framtida studier. / This study explores differences between two types of fire suppression systems: traditional watersprinkler system and high-pressure water mist system from the perspective of fire protection aswell as environmental properties. The purpose of this study is to gain a deeper understanding ofthese two systems and their use for fire protection.Traditional water sprinkler systems systems showed to offer effective fire detection and quickresponse thanks to heat-sensitive glass bulbs. It was also particiularly more effective in largeopen spaces. Traditional water sprinklers have also appeared to be effective for enfironmentswith high fibrosity, such as sawmills.High-pressure water has shown several advantages, such as early fire detection and responsetime, as well as a more efficient fire extinguishing capacity. The system uses small waterdroplets discharged at high pressure, which creates a larger coverage area and leads to up to90% less water usage. This reduces the risk of water damage and makes the system particularlysuitable for use in confined spaces and for protecting objects like lithium-ion batteries, as wellas in most other environments except those with high fibrosity.From an environmental perspective, water mist proved to be superior from several aspects. Thisincludes reducing water usage, which leads to less, environmentally hazardous firewater, thatneeds to be managed after extinguishing a fire. Higher energy efficiency is also achieved,resulting in lower carbon dioxide emissions because the pump does not need to handle as muchwater as a traditional sprinkler system. High-pressure water mist also contributes to improvedair quality by suppressing hazardous fire gases.In conclusion this study has shown important insights and conclusions, offering a betterunderstanding of the compared fire protection systems. The analyses indicate that both high-pressure water mist and traditional water sprinkler systems have their specific advantagesdepending on their usage areas. The purpose of the study was to investigate and compare thesetwo systems with regard to their fire-fighting capabilities, contributing to a more efficient firesuppression. There has been a lack of information from previous studies, making the subjectvery interesting to explore more in future studies.
52

Viewing the Long Take in Post-World War II Films: A Cognitive Approach

Chang, Hsin-Ning 29 December 2008 (has links)
No description available.
53

Dentro do nevoeiro: diálogos cruzados entre arte e arquitetura contemporânea / Inside the mist: crossed dialogues between contemporary art and architecture

Wisnik, Guilherme 10 May 2012 (has links)
No \"campo ampliado\" da cultura contemporânea, arte e arquitetura partilham cada vez mais questões comuns. Assim, seja em relações de colaboração, ou seja em relações de afrontamento, a arquitetura e a arte hoje dissolvem suas antigas fronteiras disciplinares para compor um poderoso complexo social e midiático, cujo sentido é fundamental para a compreensão do mundo contemporâneo. Sem isolar a problemática brasileira em relação ao conjunto da produção mundial, esse trabalho se propõe o desafio de pensar o eclipsamento da tectônica, da materialidade e da noção de trabalho em um mundo globalizado e dominado por produções imateriais de valor, como o capital financeiro. Evitando estabelecer um juízo definitivo sobre essa questão, procura-se entender como as produções de alguns arquitetos e artistas contemporâneos lidam com a realidade de um mundo cada vez mais impalpável e convertido em imagem, isto é, consumido permanentemente. A hipótese assumida aqui é a de que, na impossibilidade de se restaurar a resistência do mundo e da matéria - que pudesse recolocar em causa a \"estética da formatividade\" moderna -, alguns dos melhores artistas e arquitetos contemporâneos traduzem o dilema atual na forma de uma perda de foco da imagem ou do objeto, que se traduz também em uma voluntária busca pela ausência de forma. Desse modo, a poética do informe e a nuvem são, a meu ver, expressões potentes da crise contemporânea. / In the \"expanded field\" of contemporary culture, arts and architecture increasingly share common issues. Hence, whether in relations of collaboration or confrontation, arts and architecture dissolve their old disciplinary boundaries to form a powerful social and media framework, which meaning is essential for the understanding of the contemporary world. Encompassing the Brazilian problematic in relation to the body of international production, this research attempts to undertake the challenge of reflecting about the hiding tectonic, materiality and perception of work in a globalized world dominated by the immaterial production of value, such as the financial capital. Although this research precludes a definitive judgment about this issue, it attempts to understand how the outputs of some contemporary architects and artists deal with the reality of a world that is ever more intangible and converted in images, and in other words, permanently consumed. The hypothesis posed here is that, in the impossibility of restoring the resistance of the world and matter - which would put back in discussion the modern \"formativeness of aesthetics\" -, some of the most prestigious contemporary artists and architects translate the current dilemma in the loss of focus in images or objects, which also translates itself in a voluntary search for the absence of form. Hence, the poetics of formless and clouds are, from my point of view, powerful expressions of the contemporary crises.
54

Estudo da melhoria do desempenho de sistemas de resfriamento evaporativo por micro aspersão de água / Study of improvement the evaporative cooling system performance by water misting systems

Zapaterra, Cássio Luiz Ianni 29 September 2016 (has links)
Disponibilidade dos recursos energéticos junto com o despertar da consciência ambiental criaram um interesse por uma condição climática sensível compatível com os recursos disponíveis. Dentro desse cenário o trabalho se volta à necessidade de se criarem e manterem ambientes industriais termicamente adequados aos processos de produção para minimizar as interferências que as condições ambientais exercem sobre os custos dos processos de produtivos e sobre o consumo energético. Os sistemas de resfriamento evaporativo, por sua vez, têm sido a ferramenta de maior potencial de aplicação na criação de ambientes termicamente adequados aos processos. Este modelo revisto de conforto térmico nos coloca um passo à frente para o aumento eficiência energética na construção de projeto de climatização vinculados a temperaturas interiores que atendam conjuntamente tanto aos ocupantes como às atividades que desenvolvem no interior da área climatizada. Apesar de esse sistema apresentar vantagens operacionais, quando comparado a outros sistemas convencionais, existem certas limitações no seu desempenho. Uma das maiores dificuldades das instalações destes sistemas reside na existência de incertezas em qualquer resultado. Possibilitar um controle dos parâmetros, minimizando os erros de aplicação, evitando criar no ambiente um desconforto de tal grau que inviabilize sua aplicação, é o fundamento deste trabalho. A busca passa a ser pela garantia da aceitabilidade dos resultados do sistema projetado e seus limites de aplicabilidade. O estudo das variáveis que interferem no processo do resfriamento por micro aspersão permitiu desenvolver um processo que alterara esses parâmetros durante o funcionamento do sistema, interferindo, conforme a necessidade no seu desempenho, garantindo a completa evaporação da água micro aspergida. / Energy resources along with an environmental conscience awakening has created an interest in sensitive climate together with a more understanding regarding the use of available resources. Inside this scenario our work focus on the needs of creating and maintaining industrial environments thermally suited to these production processes that seeking to minimize interference that environmental conditions have on the costs of production processes and energy consumption. Evaporative cooling systems, in turn, has been a interesting tool to be used in the creation of thermally suitable environments to these processes. This new revised thermal comfort model puts us a step forward to increase energy efficiency in elaborating air treatment projects linked to indoor temperatures that meet both the occupants and the activities that develop inside the controlled area. Although this system has operational advantages when compared to other conventional systems, there are some limitations in their performance. A major difficulty of the installation envolving these systems is about the existence of uncertainty in any results. To allow the control of these parameters in order to minimize the errors in this kind of application and to avoid creating environmental discomfort to such a degree that prevent the implementation, it is the foundation of this work. The search is to ensure the acceptability of the results of the system designed and their limits of applicability. The study of the variables that affect the cooling process by misting allowed us to develop a process that altered these parameters during operation of the system, interfering, as required in its performance, ensuring complete evaporation of water applied by misting in the area.
55

Vtáčie spoločenstvá pozdĺž výškového gradientu na Kamerunskej hore z pohľadu odchytových dát / Bird Communities Along the Altitudinal Gradient on Mt. Cameroon: Perspectives from Mist Nets

Petruf, Miroslav January 2019 (has links)
in English Mt. Cameroon is a hotspot of diversity and endemism in Africa. Recent research of avian bird communities along the elevational gradient on Mt. Cameroon based on point counts has shown low-elevation plateau of species richness. At the same time, range-restricted montane populations of birds on Mt. Cameroon are unusually abundant if compared to lowland species. I analysed data on community composition, species richness and abundance of birds using an alternative quantitative method - 200 m of understory mist nets erected for three consecutive days across seven elevational plots along the forested gradient of the Mt. Cameroon. First, I looked at the technical limits of this method and confirmed the general opinion that they are better at detecting small birds below 33 g, and that they mostly detected fewer individuals after the first day and always detected fewer new species after the first day of mist-netting. Mist nets detected high proportions of ground-feeding and understory birds and low proportions of birds foraging in higher strata in the lowland forest, which has a scarce understory and a dense canopy. Mist nets recorded similar proportions of birds foraging in all forest strata in the vastly open mid-elevation forest, which has a dense herbaceous understory. They detected higher...
56

Τυρβώδης ροή σταγονιδίων σε στρωματοποιημένο θερμοκρασιακό πεδίο

Βούρος, Ανδρέας 27 May 2014 (has links)
Η διδακτορική διατριβή πραγματεύεται την πειραματική διερεύνηση της αλληλεπίδρασης δέσμης εκροής νέφους σταγονιδίων νερού με το θερμικά στρωματοποιημένο,τυρβώδες ρευστο-θερμικό πεδίο που αναπτύσσεται πάνω από οριζόντια θερμαινόμενη επίπεδη επιφάνεια. Τα φαινόμενα και οι φυσικοί μηχανισμοί που διέπουν την ως άνω αλληλεπίδραση πέρα από τη σημασία τους σε σχέση με τη βασική έρευνα στο πεδίο των ρευστοθερμικών φαινομένων, παρουσιάζουν ενδιαφέρον σε πληθώρα πρακτικών προβλημάτων όπως κατά τον ψεκασμό καυσίμου σε κινητήρες εσωτερικής καύσης και καυστήρες, στη διφασική ψύξη ηλεκτρονικών, στην μετεωρολογία, στην πυρόσβεση, σε διεργασίες απόθεσης και επικάλυψης κ.α. Το ρευστο-θερμικό πεδίο αναπτύσσεται πάνω από οριζόντια θερμαινόμενη επιφάνεια μεταλλικής πλάκας μέσα σε ορθογωνική κοιλότητα με ανοικτή οροφή. Το νέφος σταγονιδίων δημιουργείται σε έναν νεφελοποιητή και εκτοξεύεται μέσα από ένα ακροφύσιο κυλινδρικού σωλήνα εσωτερικής διαμέτρου 4mm, κάθετα προς την οριζόντια επίπεδη επιφάνεια και σε σημαντική απόσταση από αυτήν (50cm), δημιουργώντας αρχικά μια διφασική δέσμη εκροής σταγονιδίων. Για την δημιουργία βάσης δεδομένων αναφοράς, σημαντικό μέρος της εργασίας αναφέρεται στην καταγραφή και μελέτη του θερμικού πεδίου ελεύθερης συναγωγής που δημιουργείται πάνω από τη θερμαινόμενη πλάκα χωρίς την παρουσία σταγονιδίων. Αντίστοιχα μελετήθηκε η ανάπτυξη της δέσμης εκροής σταγονιδίων σε ισοθερμοκρασιακές συνθήκες. Η παραμετρική μελέτη της αλληλεπίδρασης δέσμης εκροής σταγονιδίων και θερμικά στρωματοποιημένου πεδίου πραγματοποιήθηκε για δέσμες σε δύο αριθμούς Reynolds και για δύο ρυθμούς ροής θερμότητας από την πλάκα. Οι αριθμοί Reynolds που επιβάλλονται στη ροή δέσμης του νέφους (mistjet) είναι σχετικά χαμηλοί έτσι ώστε να ισχυροποιηθεί σχετικά η επίδραση του τοιχώματος και κυρίως οι ροϊκές δομές που δημιουργούνται λόγω των ανωστικών δυνάμεων κοντά στη θερμαινόμενη επιφάνεια. Η σύνθετη ροή που παράγεται λόγω της σημαντικής απόστασης μεταξύ του ακροφυσίου και της επίπεδης επιφάνειας - στόχου κατατάσσεται στην κατηγορία των δεσμών εκροής ασθενούς πρόσκρουσης. Οι παράμετροι που εξετάζονται περιλαμβάνουν μέσα και τυρβώδη χαρακτηριστικά τόσο των σταγόνων (μέγεθος και ταχύτητα), όσο και της θερμοκρασιακής κατανομής πάνω από την θερμαινόμενη πλάκα. Το θερμικό πεδίο σε συνθήκες ελεύθερης μεταφοράς και υπό την επίδραση της ροής των σταγονιδίων καταγράφτηκε με τη βοήθεια θερμοζεύγους πολύ μικρών διαστάσεων ώστε να αλλοιώνει όσο το δυνατόν λιγότερο τη ροή. Οι διαστάσεις του αισθητηρίου είναι σημαντικά μικρότερες της κλίμακας μήκους Kolmogorov και επομένως το αισθητήριο κρίθηκε ικανό για την ανάλυση όλων των σχετικών κλιμάκων της ροής. Το πεδίο νέφους σταγονιδίων μελετήθηκε με την τεχνική Ανεμομετρίας Φάσης Doppler (PhaseDopplerAnemometry - PDA) η οποία επιτρέπει την μέτρηση τόσο της ταχύτητας όσο και του μεγέθους των σταγονιδίων παρέχοντας τη δυνατότητα συσχέτισης των δύο μεγεθών για τον ενδελεχή χαρακτηρισμό της συμπεριφοράς των σταγονιδίων. Η τεχνική αυτή είναι μια από τις λίγες μη παρεμβατικές μεθόδους σημειακών μετρήσεων σε διφασικά ροϊκά πεδία η οποία δίνει πληροφορία για τη συγκέντρωση και την παροχή, με την τελευταία να αποτελεί σημαντικό εργαλείο στον υπολογισμό της εξάτμισης. Τα αποτελέσματα των μετρήσεων κατά την αλληλεπίδραση των πεδίων (θερμικού και σταγονιδίων) μελετώνται και συγκρίνονται με τις συνθήκες αναφοράς της στρωματοποιημένης ροής του θερμοκρασιακού πεδίου και της ισόθερμης ροής του πεδίου ταχυτήτων δίνοντας πληροφορία για την επίδραση του νέφους σταγονιδίων στους μηχανισμούς τυρβώδους μεταφοράς. Αναγνωρίστηκε ως κυρίαρχη δομή του πεδίου συναγωγής το κινούμενο πλούμιο συχνά μορφής μανιταριού. Η μορφή των κατανομών πυκνότητας πιθανότητας (PDF) ερμηνεύθηκε σε σχέση με το ιστορικό δημιουργίας και ανταλαγών θερμότητας των επί μέρους αερίων μαζών που διέρχοτναι από τη θέση μέτρησης. Στις κατανομές φασματικής ισχύος (PSD) του σήματος της θερμοκρασίας αναγνωρίσθηκε ιδιοσυχνότηταπου υποδεικνύει την παρουσία δομής μεγάλης κλίμακας. Αναφορικά με το πεδίο σταγονιδίων παρατηρήθηκε ότι η παρουσία της επιφάνειας – στόχου επιβραδύνει τις δέσμες πρόσπτωσης ελαττώνοντας και τις διακυμάνσεις στην περιοχή του τοιχώματος. Η θέρμανση επηρεάζει τις μέσες και κυμαινόμενες ταχύτητες σε σημαντική απόσταση από την οριζόντια πλάκα, ενώ το μέγεθος των σταγονιδίων μειώνεται κατάντη της ροής με διαφορετικές τάσεις ως προς τον Re. Αυξημένες τιμές της μέσης διαμέτρου Sauter (D32) παρατηρούνται κοντά στην επιφάνεια ειδικά για την περίπτωση ισόθερμου ψεκασμού του υψηλότερου Re. Η θέρμανση της επιφάνειας έχει σημαντική επίπτωση στον περιορισμό της αυξητικής τάσης της παροχής αέρα λόγω συμπαράσυρσης, που είναι πιο εμφανής στις περιπτώσεις χαμηλού Re. / The interaction of a water mist jet with the thermally stratified turbulent field developing over a horizontal heated flat plate, in an open top cavity, is investigated experimentally. The physical phenomena dominating this interaction, besides their importance for theoretical thermo-fluids, influence a wide spectrum of applications including fuel injection in internal combustion engines and burners, electronics cooling, meteorology, fire extinguishing, deposition and coating processes etc. Water mist, generated in a nebulizer, is sprayed through a cylindrical orifice of internal diameter 4mm, vertically, towards the horizontal surface and at considerable distance from it (50cm). In order to establish a reference case data base, a significant part of the work refers to data collection and study on the thermal convection field characteristics, in the absence of the spray mist, as well as on the isothermal mist jet development. The interaction field has been investigated for mist jets of two Reynolds numbers and at two flat plate heating rates. The mist jet Reynolds numbers were rather low in order to enhance the influence of the plate and the flow structures generated due to buoyancy. Mean and turbulent characteristics of the spray (velocity and size) and the temperature distribution were monitored. A small thermocouple, significantly smaller than the Kolmogorov length scale, was used for temperature measurements. Droplet velocities and sizes were measured with Phase Doppler Anemometry, which also provided concentration and flux measurements. Moving plumes, often in the form of mushrooms, were identified as the dominant structures in the convection field. The form of temperature probability density functions was related to the past history of formation and heat exchange of air masses crossing the measuring point. An eigenfrequency, identified in the temperature power spectra indicates the presence of a large scale structure. The presence of the target plate decelerates the mist jets reducing also turbulent fluctuations close to the surface. Heating influences the mean and fluctuating velocities at considerable distance from the plate, reducing the rate of jet mass flux growth due to entrainment, more evidently for the low Re jet. Droplet sizes decrease downstream, presenting different trends in relation to Re. Increased values of the Sauter mean diameter (D32) are observed very close to the plate surface, particularly for the high Re number, isothermal jet.
57

Le flou dans le cinéma des années 1990-2010 : une image-symptôme / Blur in the 1990s to 2010s cinema : a symptom-image

Vally, Hélène 10 November 2015 (has links)
Depuis les années 1990, le flou a envahi les écrans, touchant toutes les productions audiovisuelles, qu’ils s’agissent des films d’auteur, des blockbusters, des séries, ou encore des publicités. S’il est le plus souvent devenu un composant narratif, voire purement « cosmétique », des longs-métrages, certains réalisateurs tentent de se dégager de cet usage normé afin de jouer avec son potentiel menaçant, que nous savons qualifié de symptomal. Le terme de « symptôme », qui se réfère à l’usage qu’en fait Georges Didi-Huberman, renvoie à un contre-régime de l’image qui vient soulever le régime figuratif. En privilégiant une approche esthétique, phénoménologique et sémiologique, notre thèse met au jour la puissance symptomale du flou, à savoir son potentiel figural, haptique ou encore informe. Selon la théorie développée par Georges Didi-Huberman à partir des écrits de Sigmund Freud, le terme de « symptôme »fait également écho au mouvement du temps, c’est-à-dire au travail qu’opèrent les hantises, les survivances au sein des images afin d’ébranler, de faire vaciller le régime figuratif. Le flou-symptôme est donc aussi envisagé à partir de l’angle du temps, d’un temps qui malmène la représentation, la narration. Notre attention se porte sur différents types de flou, qu’il enveloppe totalement ou partiellement l’image(faible profondeur de champ), s’immisce progressivement dans l’image (mouvement de mise au point), ou encore résulte d’un travail sur le montage rapide (flicker) et la matière (définition de l’image, flou atmosphérique). Dans ce travail, nous analysons toutes ces différentes formes de flou afin de révéler que si certains réalisateurs s’emploient à défaire la fiction première, c’est pour mieux esquisser de nouvelles lignes de fuite narratives, des vies nouvelles. / Since the 90s, blur has invaded screens through all audiovisual productions. This phenomenon can be found not only in arthouse movies but also in blockbusters, TV series, or commercials. Its recurrent appearance as a narrative component, or even “cosmetic”, led some directors to grow away from this standardized use and to fully develop its threatening potential, that we call here symptomal. Symptom,according to Georges Didi-Huberman's works, refers to a counter-regime in which the image upraises the figurative regime. By favoring an aesthetic, phenomenological, and semiologistic approach, this thesisreveals the symptomal power of the blur, namely its figural, haptic, and formless potential. According to the theory that Georges Didi-Huberman elaborated from Sigmund Freud's work, the term “symptom”resonates with the flow of time, id est the labor operated by hauntings and survivances within images in order to undermine and shake the figurative regime. Thus the blur-symptom is also envisioned through the scope of time, a time which destabilizes representation and narration. Our focus is on the different types of blur : an image completely or partially blurred (shallow depth of field), blurring through a motion in the focus (focus-through), or through flickers and even a processing of the matter (image definition andatmospheric blur). In this study, we analyze these different forms of blur to reveal that some directors strive to dismantle the original fiction. Doing so, they eventually sketch new narrative lines of flight, newlives.
58

Eram realmente pitag?rico(a)s os homens e mulheres catalogado(a)s por J?mblico em sua obra Vida de Pit?goras?

Silva, Josildo Jose Barbosa da 25 October 2010 (has links)
Made available in DSpace on 2014-12-17T14:36:18Z (GMT). No. of bitstreams: 1 JosildoJBS_TESE.pdf: 1777094 bytes, checksum: a9a39551fbb840b0d01e7dbe25e6122d (MD5) Previous issue date: 2010-10-25 / Pythagoras was one of the most important pre-Socratic thinkers, and the movement he founded, Pythagoreanism, influenced a whole thought later in religion and science. Iamblichus, an important Neoplatonic and Neopythagorean philosopher of the third century AD, produced one of the most important biographies of Pythagoras in his work Life of Pythagoras. In it he portrays the life of Pythagoras and provides information on Pythagoreanism, such as the Pythagorean religious community which resembled the cult of mysteries; the Pythagorean involvement in political affairs and in the government in southern Italy, the use of music by the Pythagoreans (means of purification of healing, use of theoretical study), the Pythagorean ethic (Pythagorean friendship and loyalty, temperance, self-control, inner balance); justice; and the attack on the Pythagoreans. Also in this biography, Iamblichus, almost seven hundred years after the termination of the Pythagorean School, established a catalog list with the names of two hundred and eighteen men and sixteen women, supposedly Pythagoreans of different nationalities. Based on this biography, a question was raised: to what extent and in what ways, can the Pythagoreans quoted by Iamblichus really be classified as Pythagoreans? We will take as guiding elements to search for answers to our central problem the following general objectives: to identify, whenever possible, which of the men and women listed in the Iamblichus catalog may be deemed Pythagorean and specific; (a) to describe the mystery religions; (b) to reflect on the similarities between the cult of mysteries and the Pythagorean School; (c) to develop criteria to define what is being a Pythagorean; (d) to define a Pythagorean; (e) to identify, if possible, through names, places of birth, life, thoughts, work, lifestyle, generation, etc.., each of the men and women listed by Iamblichus; (f) to highlight who, in the catalog, could really be considered Pythagorean, or adjusting to one or more criteria established in c, or also to the provisions of item d. To realize these goals, we conducted a literature review based on ancient sources that discuss the Pythagoreanism, especially Iamblichus (1986), Plato (2000), Aristotle (2009), as well as modern scholars of the Pythagorean movement, Cameron (1938), Burnet (1955), Burkert (1972), Barnes (1997), Gorman (n.d.), Guthrie (1988), Khan (1999), Matt?i (2000), Kirk, Raven and Shofield (2005), Fossa and Gorman (n.d.) (2010). The results of our survey show that, despite little or no availability of information on the names of alleged Pythagoreans listed by Iamblichus, if we apply the criteria and the definition set by us of what comes to be a Pythagorean to some names for which we have evidence, it is possible to assume that Iamblichus produced a list which included some Pythagoreans / Pit?goras ? considerado um dos mais importantes pensadores pr?-socr?ticos. A escola pitag?rica, por ele fundada, influenciou todo um pensar posterior na religi?o e na ci?ncia. J?mblico, fil?sofo neoplat?nico e neopitag?rico do s?culo III d.C., elaborou, quase setecentos anos ap?s o t?rmino do movimento pitag?rico, uma das tr?s biografias de Pit?goras, a Vida de Pit?goras. Nela, ele retrata a vida desse fil?sofo e nos fornece informa??es sobre o pitagorismo: uma comunidade religiosa assemelhada ao culto de mist?rios; o envolvimento de seus participantes em assuntos pol?ticos e no governo no sul da It?lia; a exalta??o dada ? m?sica (meio de purifica??o, de cura, recurso de estudo te?rico), ? ?tica (amizade, lealdade, temperan?a, autocontrole, equil?brio interior), ? justi?a, e o ataque sofrido pelos pitag?ricos. Ao final dessa biografia, J?mblico elabora um cat?logo com os nomes de duzentos e dezoito homens e dezesseis mulheres, suposto(a)s pitag?rico(a)s de diversas nacionalidades. Tomando como base essa biografia, lan?a-se a quest?o: at? que ponto, e em quais aspectos, esses homens e mulheres citado(a)s por J?mblico podem realmente ser classificados como pitag?rico(a)s? Tomaremos como elementos norteadores ? busca de respostas para nosso problema central os seguintes objetivos (i) geral, identificar, quando poss?vel, quais dos homens e mulheres listados no cat?logo de J?mblico podem ser considerados pitag?ricos, e (ii) espec?ficos: (a) caracterizar as religi?es de mist?rios; (b) refletir sobre as semelhan?as entre o culto de mist?rios e a escola pitag?rica; (c) desenvolver crit?rios que v?o definir o que ? ser um pitag?rico; (d) definir um pitag?rico; (e) identificar, se poss?vel, atrav?s dos nomes, locais de nascimento, vidas, pensamentos, obras, estilo de vida, gera??o, etc., cada um dos homens e mulheres listados por J?mblico; (f) destacar, no cat?logo, quem realmente poderia ser considerado um(a) pitag?rico (a), ou se adequando a um ou v?rios crit?rios estabelecidos em c, ou atendendo ao disposto no item d. Para dar conta de tais objetivos, realizamos uma pesquisa bibliogr?fica valendo-se de fontes antigas que discutem o pitagorismo, principalmente J?mblico (1986), Plat?o (2000/s.d.), Arist?teles (s.d.), e modernos estudiosos desse movimento: Cameron (1938), Burnet (1955), Burkert (1972), Guthrie (1988/2003), Barnes (1997), Khan (1999), Gorman (1979), Matt?i (2000), Kirk, Raven & Shofield (2005), e Fossa (2006/2010). Os resultados de nossa pesquisa mostram que, se utilizarmos as raras informa??es acerca de poucos desse(a)s suposto(a)s homens e mulheres catalogado(a)s por J?mblico, e se aplicarmos sobre eles os crit?rios e a defini??o por n?s anteriormente estabelecidos sobre o que vem a ser um pitag?rico, ? poss?vel supor que a lista elaborada por J?mblico pode estar constitu?da por alguns homens e mulheres que possu?am um modo de vida e um interesse por determinados assuntos caracteristicamente pitag?ricos
59

Estudo da melhoria do desempenho de sistemas de resfriamento evaporativo por micro aspersão de água / Study of improvement the evaporative cooling system performance by water misting systems

Cássio Luiz Ianni Zapaterra 29 September 2016 (has links)
Disponibilidade dos recursos energéticos junto com o despertar da consciência ambiental criaram um interesse por uma condição climática sensível compatível com os recursos disponíveis. Dentro desse cenário o trabalho se volta à necessidade de se criarem e manterem ambientes industriais termicamente adequados aos processos de produção para minimizar as interferências que as condições ambientais exercem sobre os custos dos processos de produtivos e sobre o consumo energético. Os sistemas de resfriamento evaporativo, por sua vez, têm sido a ferramenta de maior potencial de aplicação na criação de ambientes termicamente adequados aos processos. Este modelo revisto de conforto térmico nos coloca um passo à frente para o aumento eficiência energética na construção de projeto de climatização vinculados a temperaturas interiores que atendam conjuntamente tanto aos ocupantes como às atividades que desenvolvem no interior da área climatizada. Apesar de esse sistema apresentar vantagens operacionais, quando comparado a outros sistemas convencionais, existem certas limitações no seu desempenho. Uma das maiores dificuldades das instalações destes sistemas reside na existência de incertezas em qualquer resultado. Possibilitar um controle dos parâmetros, minimizando os erros de aplicação, evitando criar no ambiente um desconforto de tal grau que inviabilize sua aplicação, é o fundamento deste trabalho. A busca passa a ser pela garantia da aceitabilidade dos resultados do sistema projetado e seus limites de aplicabilidade. O estudo das variáveis que interferem no processo do resfriamento por micro aspersão permitiu desenvolver um processo que alterara esses parâmetros durante o funcionamento do sistema, interferindo, conforme a necessidade no seu desempenho, garantindo a completa evaporação da água micro aspergida. / Energy resources along with an environmental conscience awakening has created an interest in sensitive climate together with a more understanding regarding the use of available resources. Inside this scenario our work focus on the needs of creating and maintaining industrial environments thermally suited to these production processes that seeking to minimize interference that environmental conditions have on the costs of production processes and energy consumption. Evaporative cooling systems, in turn, has been a interesting tool to be used in the creation of thermally suitable environments to these processes. This new revised thermal comfort model puts us a step forward to increase energy efficiency in elaborating air treatment projects linked to indoor temperatures that meet both the occupants and the activities that develop inside the controlled area. Although this system has operational advantages when compared to other conventional systems, there are some limitations in their performance. A major difficulty of the installation envolving these systems is about the existence of uncertainty in any results. To allow the control of these parameters in order to minimize the errors in this kind of application and to avoid creating environmental discomfort to such a degree that prevent the implementation, it is the foundation of this work. The search is to ensure the acceptability of the results of the system designed and their limits of applicability. The study of the variables that affect the cooling process by misting allowed us to develop a process that altered these parameters during operation of the system, interfering, as required in its performance, ensuring complete evaporation of water applied by misting in the area.
60

Modélisation de l'interaction entre un brouillard d'eau et un foyer en tunnel / Computational study of water mist in a tunnel fire application

Blanchard, Elizabeth 04 November 2011 (has links)
Ce travail de thèse est consacré à l'étude de l'interaction entre une aspersion par brouillard d'eau et un feu. Il s'appuie sur une modélisation existante figurant dans le code à champs « Fire Dynamics Simulator ». L'approche consiste en premier lieu à appréhender, par le biais d'une synthèse bibliographique, les phénomènes physiques mis en jeu lors d'un feu en tunnel et lors d'une aspersion par brouillard d'eau. Ensuite, un travail d'évaluation est mené. L'évaluation se veut évolutive, en commençant par des cas simples à l'échelle du laboratoire afin de travailler le plus indépendamment possible sur certaines parties du modèle d'aspersion, pour ensuite s'intéresser à la configuration tunnel. Ce travail d'évaluation permet de mieux cerner les aptitudes du code à simuler les phénomènes physiques mis en jeu lors d'un feu en tunnel soumis ou non à une aspersion. Des comparaisons sont effectuées avec plusieurs essais réalisés entre 2005 et 2008 sur une maquette de tunnel à échelle 1/3. Une fois cette évaluation accomplie, l'outil est exploité pour améliorer notre compréhension des phénomènes d'interaction entre le brouillard d'eau, la ventilation du tunnel et le feu. En particulier, l'influence de l'aspersion sur l'écoulement longitudinal est analysée, le rôle énergétique du brouillard d'eau est mesuré et les modes de transfert de chaleur associés aux gouttes sont quantifiés. Cette exploitation permet également d'évaluer numériquement l'influence de quelques paramètres sur l'efficacité de l'aspersion telles que la vitesse de ventilation longitudinale, la puissance du feu et la taille des gouttes pulvérisées. En dernier lieu, le code champs est exploité dans le cadre d'une étude numérique exploratoire en vue d'une campagne d'essais en bâtiment pour appréhender l'interaction entre l'aspersion, la nappe de fumée et le désenfumage mécanique / This work deals with the study of the phenomena involved when a water mist is sprayed in a tunnel fire environment. It relies on an extensive use of numerical simulations using the CFD code "Fire Dynamics Simulator". The first chapter of this thesis provides an overview of the tunnel fire characteristics and the phenomena involved when the water mist is sprayed. A bibliographical review on the research on tunnel fires with or without any mitigation system is conducted, allowing to outline the reason and the context for this research. In the second and third chapters, the computational tool undergoes testing. It is verified and validated based on comparison with analytical solutions and experimental cases of increasing complexity: from the laboratory scale for assessing one particular part of the water spray model (chapter 2) up to the tunnel scale (chapter 3). For the last case, the code validation makes use of the results of a reduced scale (1/3rd) tunnel fire test campaign conducted between 2005 and 2008. Once the validation is achieved, the computational tool is used intensively in the third chapter in order to improve the understanding of the interaction phenomena between water mist, tunnel longitudinal ventilation and fire. In particular, the water mist influence on the tunnel air flow is studied, the water mist heat contribution is quantified and the heat transfered to the droplets is identified. Furthermore, the CFD code is used to assess the impact of the longitudinal air velocity, the heat release rate and the water droplet size on the water mist efficiency. The last chapter illustrates how a CFD code can be used on a given situation, here a compartment fire test campaign, in order to foresee the interaction between the water mist, the smoke layer and the smoke extraction.

Page generated in 0.0741 seconds