Buildings located near airports may be subjected to significant noise levels due to aircraft flyovers. Aircraft noise is particularly annoying when compared to other traffic noises due to its intermittent nature. While noise control is typically performed at the source, sound insulation programs are in place to improve the acoustic performance of a residence affected by the flyovers. Noise Level Reduction (NLR) is a common metric used in the United States to determine whether a residence qualifies for such programs. Sound insulation programs are available to houses that have an indoor Day Night Average Sound Level (DNL) greater than 45 dBA. NLR is a single-number metric used to quantify the ability for a building or building element to reduce the transmission of external sound pressure levels generated by aircraft. In addition to determining whether a residence qualifies, NLR can be used to quantify the effectiveness of the modifications performed as a result of the sound insulation program. NLR measurements with a loudspeaker offer an alternative method to those performed with aircraft flyovers, offering flexibility to the consultants that perform these measurements in the field. The purpose of this research was to better understand and improve the loudspeaker test for measuring NLR, providing a resource to the aircraft noise industry. Testing was completed on a "test house" that was constructed on campus with construction methods typical of a mixed-humid climate. The angular dependency, repeatability, and reproducibility of NLR, among other factors, were evaluated with field measurements. Significant NLR variations were observed with changes in lateral and vertical angles of incidence.

Este trabalho apresenta um modelo teórico que procura explicar a origem de um pico anômalo de corrente, observado na fase faraeletrica do copolímero P(VDF/TrFE), nos processos de descarga. Quando uma voltagem tipo V(t) = Vo S(t) é aplicado em materiais isolantes, correntes elétricas observadas em medidas, de carga-descarga decaem aproximadamente com T-n e obedecem ao principio da superposição linear (PSL). Esse comportamento e também observado em polímeros dielétricos. Entretanto, nos processos de descarga, acima da temperatura de Curie do copolímero p (VDF/TrFE), surge um pico anomalo de corrente que viola, aparentemente, o (PSL). Apresentamos um modelo de migração de cargas de espaço em presença de armadilhas, que pode ser responsável pelo pico de corrente e que estaria superposta a corrente de descarga da absorção dielétrica, conforme o modelo, durante os processos de carga, impurezas extrínsecas seriam varridas, pelo campo, do volume da amostra e ficariam, preferencialmente, presas em armadilhas de superfície. Nos processos de descarga, essas cargas se deslocariam em direção ao interior da amostra, devido a repulsão Coulombiana. Esse mecanismo de condução gera um pico de corrente. A aplicação do modelo, permitiu-nos inferir valores de parâmetros como a mobilidade dos portadores de carga e o tempo de transito. / A model based on space charge migration to explain an anomalous electric current peak on films of P (VDF/TrFE) copolymer in its paraelectric phase is presented. In general step-voltage current measurements of insulating polymeric materials obey the Principle of Linear Super-position. However, an unexpected anomalous peak was observed in discharge currents in measurements performed with P (VDF/TrFE) above the Curie temperature. We have assumed that space charges were dragged from the bulk of the sample by the external field during the charge measurement, and trapped close to the surface of the sample in a region where the concentration of traps would be very high. Two methods were developed to calculate the magnitude of the current peak: I) assuming a given space charge distribution during the discharge measurement, and II) considering the movement of thin discrete layers of charge under the influence of the internal field.

Uma condutividade evanescente, dependente do tempo, tem sido detectada nos filmes de PVDF da BembergFolien. Após muitos ciclos de polarização e despolarização, a corrente de absorção torna-se fortemente reduzida, para o mesmo nível das correntes de despolarização. Esta condutividade é facilmente observada, aparecendo na corrente de polarização pela aplicação de altos campos. É observada recuperação em amostras deixadas em atmosfera úmida. Nós interpretamos estas observações como sendo uma limpeza, pelo campo elétrico, dos íons gerados por uma acentuação da dissociação de moléculas de água absorvida no volume, pela ação deste campo. / A time dependent evanescent conductivity has been detected in BembergFoliem PVDF films. After many polarization-depolarization cycles, the absorption current became strongly reduced, to the same level as the depolarization one. It is easily seen at higher fields by a bump appearing in the polarization current Recovering is observed in samples left in humid atmosphere. We have interpreted these observations as an electric field ion cleaning of an electric field enhanced dissociation of bulk absorbed water molecules.

Neste trabalho obtivemos curvas de corrente induzida por raios-x no teflon FEP que apresentou as seguintes características: a) Inicialmente a corrente subiu, atingindo um máximo em torno dos 10s; b) Decaiu lentamente durante aproximadamente meia-hora, e; c) Atingiu um estado estacionário daí por diante. Ao se desligar a radiação, registrou-se a componente atrasada desta corrente. Usamos amostras de 25&#956m de espessura e área irradiada foi de 12,5cm2 ; o campo aplicado da ordem de 104V/cm e taxa de exposição da ordem de 102 R/S. Verificamos que depois de completada de uma medida da corrente induzida num amostra, esta não voltava a se repetir se realizada depois algumas horas; a corrente então não apresentava um máximo, indo diretamente ao valor estacionário; porém se recuperava com o tempo, repetindo a primeira medida depois de algumas semanas. Para mostrar que esta subida e descida da corrente induzida, não era devido a um efeito de campo, realizamos uma medida onde aplicamos o campo intermitente por curtos períodos de tempo, enquanto a amostra era irradiada. O resultado se mostrou igual aos realizados com tensão aplicada permanentemente. Estudamos ainda a dependência da condutividade induzida com a taxa de exposição e com o campo. Finalmente construímos um modelo teórico para o material que permitiu a obtenção de parâmetros do mesmo concordantes com o esperado. Acrescentamos a este trabalho uma curva que mostra o efeito da variação da temperatura sobre uma medida longa da absorção dielétrica. / In this work we measured X-ray indeuced currents in teflon FEP wich show the following features: a) At the beginning the current increases and reaches a maximum at about 10s; b) It decays slowly during 30 minutes, when a steady state is reached slowly during 30 minutes, when a steady state is reached the delayed conductvity was also measured. The sample were 25&#956m thick and the irradiated área was 12,5cm2; the applied field was of the order of 104 V/cm and the dose rate of the order of 102 R/S. It was observed that a new measurement of the induced conductivity does not duplicate the first one, but after a few hours it come backs to the original one. In order to show that the increase and the deacrease of the current is not caused by na electric field effect we realized a measurement where we polled the sample intermitently while it was irradiated. The current thus obtained had about the same values of the first measuments, when the voltage was applied all the time during the measurement. We also measured the absorption current f a teflon sample wich shows after some days the effect of its variation due the variation of the ambiental temperature.

Dans le domaine de l’isolation thermique du bâtiment, les évolutions réglementaires (RT2012)et normatives (NF BPE : Béton à Propriétés Thermiques, septembre 2016) incitent à évoluer vers des bétons isolants et structurels (BIS). La maîtrise de leur conductivité thermique est primordiale. Il est possible, en plus de faire appel à un squelette granulaire léger, de jouer sur la nature de la pâte en utilisant des inclusions qui apporteraient un pouvoir isolant supplémentaire : les cénosphères. Dans un contexte de facilité de mise en oeuvre, à ces propriétés est rajouté le critère auto plaçant des bétons. On parle alors de Bétons Isolants Structurels Autoplaçants (BISAP). La maitrise et la validation de ces nouvelles formules dans le respect d’une approche prescriptive a nécessité la caractérisation des matériaux à différentes échelles (de l’inclusion à l’échelle de l’ouvrage) en développant des approches expérimentales et numériques. Leur comportement à l’état frais et à l’état durci a été analysé. Les conductivités thermiques mesurées placent ces nouveaux bétons dans la catégorie Bétons Isolants Structurels au sens du nouveau référentiel. Le modèle numérique développé permet d’approcher correctement les valeurs expérimentales. D’autre part, la sensibilité des BISAP incorporant des cénosphères à plusieurs indicateurs de durabilité (porosité accessible à l’eau, perméabilité,carbonatation et retrait) a également été étudiée. L’influence des microsphères est plus ou moins notable en fonction du mécanisme abordé. / In the field of building thermal insulation, regulatory (RT2012) and standards (NF BPE: Béton à Propriétés Thermiques, September 2016) evolutions are encouraging the use of insulating structural concrete (BIS). The control of their thermal conductivity is essential. It is possible, in addition to using lightweight aggregates, to modify the composition of the cement paste by using hollow inclusions (fly ash cenospheres) to bring an additional thermal insulating potential. In a context of improved workability, to these properties is added the criterion of self-compacting concrete. The validation of these new formulas required the characterization of materials at different scales (from inclusion scale to building scale) by implementing experimental and numerical approaches. Their properties at fresh and hardened state were analyzed. The measured thermal conductivities place these new concretes in the Category of Structural Insulating Concrete in the sense of the new standard. The developed numerical model allowed approaching the experimental measurements correctly. The effect of cenospheres’ incorporation into cement paste on several durability indicators was also characterized.

Made available in DSpace on 2017-07-10T15:14:43Z (GMT). No. of bitstreams: 1 Cornelio Primieri.pdf: 3721204 bytes, checksum: 8dabdaaf2812e1f80bfd5bfcd26f1dd1 (MD5) Previous issue date: 2012-02-24 / This research aimed overall assessment of a new plant insulating fluid, using as raw vegetable oil culture of crambe (Crambe abyssinica Hochst). Specific objectives were to evaluate the oxidation stability of crambe oil with various types of typical antioxidants used in edible vegetable oils available in the domestic market, aiming at a new plant insulating fluid, using a raw vegetable oil that does not compete with human food chain / animal. The experiment was conducted at the Research Laboratory of Oil Chemistry of College Assis Gurgacz-FAG. In the municipality of Cascavel / PR, a Latitude 24 º 56 'South, Longitude 53 º 30' W and altitude of 682 m in the period from September to December 2011. The methodology used was called Rancimat equipment, a device which simulates the two main parameters that affect the oxidation stability of greases matters, which are the action of high temperatures and the presence of oxygen, which presents results as an induction period which is represented by periods in hours. From the data collected during testing of the samples prepared using the Rancimat temperatures of 110 ° C and 130 ° C, an average was calculated for each typ e of antioxidant, as well as their concentrations and mixtures. The survey results showed that the sample that showed the best oxidation stability at 110 ° C was obtaine d from the use of antioxidant TBHQ in a concentration of 0.3% m / m (52.96 h). The worst case was the DBPC 0.1% m / m (6.72 h). At temperatures of 130 ° C, the best re sult was TBHQ 0.3% m / m (12.67 h) and DBPC worst case was 0.1% m / m (0.61 h). Thus, we conclude that to obtain a new fluid-based insulation plant crambe is feasible to use the antioxidant TBHQ, with a concentration of 0.3% m / m. / A presente pesquisa teve como objetivo geral a avaliação de um novo fluído vegetal isolante, utilizando como matéria prima o óleo vegetal da cultura do crambe (Crambe abyssinica Hochst). Como objetivo específico a avaliação da estabilidade à oxidação do óleo de crambe com diversos tipos de antioxidantes típicos utilizados em óleos vegetais comestíveis disponíveis no mercado nacional, visando um novo fluído vegetal isolante, utilizando matéria prima um óleo vegetal que não compete com a cadeia alimentar humana/animal. O experimento foi conduzido no Laboratório de Pesquisas em Óleo Química da Faculdade Assis Gurgacz-FAG, no município de Cascavel/PR, a uma Latitude 24º56 Sul, Longitude de 53º30 Oeste e altitude de 682 m, no período de setembro a dezembro de 2011. A metodologia utilizada foi a do equipamento denominado de Rancimat, equipamento este que simula os dois principais parâmetros que afetam a estabilidade a oxidação das matérias graxas, que são a ação das temperaturas elevadas e a presença de oxigênio, o que apresenta como resultados um período de indução que é representado por períodos em horas. A partir dos dados coletados nos ensaios das amostras elaborados no Rancimat utilizando temperaturas de 110ºC e 130ºC, foi calculada uma média para cada tipo de antioxidante, bem como suas concentrações e misturas. Os resultados da pesquisa demonstraram que a amostra que apresentou a melhor estabilidade a oxidação a 110ºC foi obtida do uso do antioxidante TBHQ com uma concentração de 0,3% m/m (52,96 h). O pior caso foi o DBPC a 0,1% m/m (6,72 h). Para temperaturas de 130ºC, o melhor resultado foi o TBHQ a 0,3% m/m (12,67 h) e o pior caso foi o DBPC a 0,1% m/m (0,61 h). Deste modo, conclui-se que para obter-se um novo fluído vegetal isolante a base de crambe é viável a utilização do antioxidante TBHQ, com uma concentração de 0,3% m/m.

Carrier dynamics in GaAs-based photoconductive terahertz (THz) sources is investigated using Monte Carlo techniques to optimize the emitted THz transients. A self-consistent Monte Carlo-Poisson solver is developed for the spatio-temporal carrier transport properties. The screening contributions to the THz radiation associated with the Coulomb and radiation fields are obtained self-consistently by incorporating the three-dimensional Maxwell equations into the solver. In addition, the enhancement of THz emission by a large trap-enhance field (TEF) near the anode in semi-insulating (SI) photoconductors is investigated. The transport properties of the photoexcited carriers in photoconductive THz sources depend markedly on the initial spatial distribution of those carriers. Thus, considerable control of the emitted THz spectrum can be attained by judiciously choosing the optical excitation spot shape on the photoconductor, since the carrier dynamics that provide the source of the THz radiation are strongly affected by the ensuing screenings. The screening contributions due to the Coulomb and radiation parts of the electromagnetic field acting back on the carrier dynamics are distinguished. The dominant component of the screening field crosses over at an excitation aperture size with full width at half maximum (FWHM) of ~100 um for a range of reasonable excitation levels. In addition, the key mechanisms responsible for the TEF near the anode of SI photoconductors are elucidated in detail. For a given optical excitation power, an enhancement of THz radiation power can be obtained using a maximally broadened excitation aperture in the TEF area elongated along the anode due to the reduction in the Coulomb and radiation screening of the TEF.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1943. / Includes bibliographical references (leaves 98-100).

Στόχος της παρούσας διπλωματικής είναι η διερεύνηση της συμπεριφοράς ενός συγκεκριμένου είδους φυτικού έλαιου που καταπονείται εντός διακένου, υπό αυξανόμενη AC τάση. Αναζητούμε, λοιπόν, την επίδραση του μονωτικού ελαίου στην τάση διάσπασης καθώς μεταβάλουμε τους διάφορους παράγοντες από οποίους εξαρτάται (π.χ. το μέγεθος διακένου, το ρυθμό φραμμικής αύξησης της τάσης {kVrms/sec}, τη θερμοκρασία, το χρόνο χαλάρωσης του υγρού μεταξύ δύο διαδοχικές μετρήσεις, την επίδραση των φυσαλίων στην μονωτική συμπεριφορά του ελαίου, κ.α.). Η διπλωματική εργασία τούτη αποτελεί μια συνεισφορά στη διεθνή ερευνητική προσπάθεια που γίνεται πάνω στο αντικείμενο της συλλογής πληροφοριών και εξαγωγής συμπερασμάτων για τη συμπεριφορά και τις ιδιότητες (ηλεκτρικές, μηχανικές, χημικές) διαφόρων τύπων σύνθετων μονώσεων. Ιδιαίτερα χρήσιμη αποσκοπεί να είναι στις διεθνείς προσπάθειες βελτίωσης των επιδόσεων και της αξιοπιστίας – με ταυτόχρονη διατήρηση ή και ελάττωση του μεγέθους των σχεδιαζόμενων μονωτικών διατάξεων – για Μετασχηματιστές Υψηλής Τάσης, που αποτελούν το κυρίαρχο μέσο στα παγκόσμια δίκτυα μεταφοράς και διανομής ηλεκτρικής ενέργειας. / This diploma thesis aims to the examination of the “behavior” of specific plant oil that is worn out within interspace under linearly increased AC voltage. So we search out the effect of the insulating oil on the voltage decomposition, as we alter the numerous factors on which it depends (the size of interspace, the rate of the voltage’s linear increase {kVrms/sec}, the temperature, the liquid’s relaxation time between two successional counts, the effect of bubbles on the oil’s insulating behavior etc).

With increased exposure to transportation noise, there have been continued efforts to help insulate homes from aircraft noise. Current aircraft noise guidelines are based primarily on outdoor sound levels. As people spend the majority of their time indoors, however, human perception is evidently more related to indoor sound levels. Investigations are being made to provide further insight into how typical residential constructions affect indoor response. A pilot study has built a single-room "test house", according to typical construction for mixed-humid climate regions, and has directly measured outdoor-to-indoor transmission of sound - with specific focus on continuous commercial aircraft signatures. The results of this study are being used to validate and improve modelling software that simulates a wide range of construction types and configurations for other US climate regions. The improved models will allow for increased flexibility in simulating the impacts of acoustic and energy retrofits. Overall, the project intends to improve the ability to predict acoustic performance for typical US construction types as well as for any possible design alterations for sound insulation.