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Análise da viabilidade da utilização do transporte por cabotagem para a movimentação de automóveis novos no Brasil: um estudo de caso; Analysis of feasibility to use cabotage for transporting new cars in Brazil: a case study

Nakamura, Carolina Yuri
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 15/04/2010 PT
Relevância na Pesquisa
36.79%
O objetivo desta dissertação é analisar a viabilidade do transporte marítimo de automóveis novos por cabotagem no Brasil, buscando uma alternativa de transporte, pois atualmente este transporte somente é realizado pelo modal rodoviário. A utilização da cabotagem como transporte de cargas tem aumentado desde a promulgação da Lei de Modernização dos Portos (lei 8.630), em 1993. Nesta mesma época, as fábricas de veículos começaram a passar por um processo de desconcentração geográfica, se deslocando da região Sudeste, e necessitando de transportes mais eficientes. Para observar se tal alternativa é viável economicamente, foi elaborado um estudo de caso e foram usados os dados de uma montadora específica. Esta montadora possui fábricas nos municípios de Camaçari (BA) e de São Bernardo do Campo (SP) e precisa distribuir sua produção em 275 concessionárias espalhadas pelo país. A partir do levantamento e análise dos custos rodoviários e de cabotagem para o transporte de automóveis, foi desenvolvido um modelo de transporte solucionado com o uso de técnicas de programação linear cujas soluções a partir da minimização dos custos de transporte apontaram para o uso ou não da cabotagem. As rotas que apresentaram maiores ganhos econômicos têm como característica uma grande distância entre a fábrica e as concessionárias e uma proximidade dos portos de destino das concessionárias.; This study aims to examine the feasibility of costal shipping of new cars by cabotage in Brazil...

Estudo do sistema duto-trocador de calor compacto para veículos de competição.; Study of duct-compact heat exchanger system for race cars.

Borsatti, Eugênio José
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 21/09/2010 PT
Relevância na Pesquisa
36.79%
Esse estudo procura integrar as áreas de termodinâmica, transferência de calor e aerodinâmica no desenvolvimento de veículos de alto desempenho. É proposta uma ferramenta computacional que auxilie a análise de alternativas de trocadores de calor compactos, parte integrante do sistema de arrefecimento veicular. O aplicativo desenvolvido, denominado TROCALC, tem dois modos de uso: para colaborar no projeto de um trocador de calor ou para avaliar o desempenho de um trocador existente. Estruturado por um conjunto de equações e parâmetros com base na metodologia de Kays e London (1984), no primeiro modo esse aplicativo fornece alternativas de trocadores a partir dos dados de rejeição de calor por parte do motor e dos valores de vazão e temperatura dos fluidos envolvidos. Para o modo de avaliação de desempenho, além dos dados de entrada já mencionados, é necessário o detalhamento da geometria de superfície do trocador para calcular a quantidade de calor que o radiador é capaz de remover do sistema e comparar com o valor de fluxo de calor rejeitado pelo motor. É adotado um estudo de caso que considerou um veículo de competição da Fórmula SAE para investigar a eficácia do aplicativo TROCALC na análise de desempenho e na definição de novas alternativas para o trocador de calor dedicado àquele automóvel. Foram realizados ensaios em laboratório com a medição de valores para a rejeição de calor...

Autismo infantil : tradução e validação da CARS (childhood autism rating scale) para uso no Brasil

Pereira, Alessandra Marques
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
27.24%
Introdução: O autismo infantil tornou-se um dos distúrbios mais estudados em neuropsiquiatria, tendo em vista a gravidade e o impacto que produz. Na ausência de um marcador biológico, seu diagnóstico permanece clínico, com base nos critérios da Associação Americana de Psiquiatria (DSM-IV). Ao longo de várias décadas, vários instrumentos foram desenvolvidos com base no DSM-IV, com objetivo de aperfeiçoar o diagnóstico do transtorno, assim como várias escalas que medem a gravidade dos sintomas também foram criadas. A Childhood Autism Rating Scale (CARS) é uma das escalas mais utilizadas como instrumento para avaliar a gravidade do autismo. Objetivo: O presente estudo objetivou traduzir, adaptar e validar uma versão em português (do Brasil) da referida escala. Métodos:estudo transversal de amostra de conveniência de crianças e adolescentes com diagnóstico de autismo infantil, em acompanhamento regular no Ambulatório de Transtornos Invasivos do Desenvolvimento, do Hospital de Clínicas de Porto Alegre.Processo de tradução, adaptação transcultural e validação conforme proposto na literatura por Sperber. Foram utilizadas, além da versão traduzida da CARS (CARS-BR), a Escala de Avaliação de Traços Autísticos (ATA) e a Escala de Avaliação Global do Funcionamento (GAF). Foram empregados os testes de correlação de Pearson para comparação entre as diferentes escalas a fim de se estimar validade convergente (ATA) e validade discriminante (GAF)...

O escalonamento da produção direcionado à preparação de veículos de uma empresa de competição automóvel; Production scheduling directed to the cars maintenance on a motorsport enterprise

Sousa, Gualter Hernâni Jesus
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Trabalho de Conclusão de Curso
Publicado em //2014 POR
Relevância na Pesquisa
37.02%
Dissertação de mestrado integrado em Engenharia Industrial (área de especialização em Gestão Industrial); Numa equipa de competição automóvel, o tempo é algo muito valioso, dada a imprevisibilidade do que poderá ocorrer em provas. Acidentes entre veículos é algo vulgar nesta atividade e a necessidade de reparar ou simplesmente rever os carros entre provas leva a uma obrigatoriedade de otimização de um tempo, geralmente escasso. Dado que não se pode alterar a data das provas e dada a ausência de uma delas devido a, por exemplo, atrasos na manutenção dos veículos, levar a elevados problemas financeiros, todo o processo de revisão deve ser efetuado no menor tempo possível. Assim, o objetivo desta dissertação será definir um escalonamento das atividades de forma a que não haja falhas na conclusão das tarefas. Para isso, foram considerados o makespan (Fmax ou Cmax) e o tempo de percurso total (Ftotal) como medidas de desempenho principais, para avaliação do desempenho do sistema de produção em causa, para levar a cabo as tarefas de verificação e manutenção dos carros para as competições planeadas. Isto deverá ser feito através da aplicação de métodos ou algoritmos heurísticos de escalonamento da produção...

The impact of macroeconomic variables on the used cars sale price

Tomé, Ana Catarina Laureano Pereira
Fonte: Instituto Universitário de Lisboa Publicador: Instituto Universitário de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2013 POR
Relevância na Pesquisa
36.79%
Mestrado em Gestão/ Classificação JEL: C21; E31.; The 2008 economic downturn triggered significant fluctuations in several scopes, namely in the automotive industry. The purpose of this dissertation is to analyse the influence of the current crisis on the sale price of second hand vehicles. A linear regression model was estimated using the Ordinary Least Squares procedure, based on a sample of used cars sold in Portugal, since 2005 to 2012. Macroeconomic variables such as Unemployment Rate, Oil Prices, Loans granted to Private Individuals, Private Consumption Indicator, Harmonized Index of Consumer Prices, among others, were tested in the estimated regression. In addition, some variables representing the own vehicle characteristics were also included. Finally, an out-of-sample analysis was performed to evaluate the predictive ability of the linear regression model. Results suggested that some of the selected macroeconomic indicators actually influence the sale price of an automobile sold in the secondary market and due to its predicting capacity can be useful to pricing procedures or just for asset valuation.; A recessão económica de 2008 desencadeou flutuações relevantes em diversos âmbitos, nomeadamente na indústria automóvel. O objetivo desta dissertação é analisar a influência da atual crise no preço de venda dos carros em segunda mão. Para tal...

Use of seatbelts in cars with automatic belts.

Williams, A F; Wells, J K; Lund, A K; Teed, N J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1992 EN
Relevância na Pesquisa
27.26%
Use of seatbelts in late model cars with automatic or manual belt systems was observed in suburban Washington, DC, Chicago, Los Angeles, and Philadelphia. In cars with automatic two-point belt systems, the use of shoulder belts by drivers was substantially higher than in the same model cars with manual three-point belts. This finding was true in varying degrees whatever the type of automatic belt, including cars with detachable nonmotorized belts, cars with detachable motorized belts, and especially cars with nondetachable motorized belts. Most of these automatic shoulder belts systems include manual lap belts. Use of lap belts was lower in cars with automatic two-point belt systems than in the same model cars with manual three-point belts; precisely how much lower could not be reliably estimated in this survey. Use of shoulder and lap belts was slightly higher in General Motors cars with detachable automatic three-point belts compared with the same model cars with manual three-point belts; in Hondas there was no difference in the rates of use of manual three-point belts and the rates of use of automatic three-point belts.

Why do red and dark-coloured cars lure aquatic insects? The attraction of water insects to car paintwork explained by reflection–polarization signals

Kriska, György; Csabai, Zoltán; Boda, Pál; Malik, Péter; Horváth, Gábor
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.18%
We reveal here the visual ecological reasons for the phenomenon that aquatic insects often land on red, black and dark-coloured cars. Monitoring the numbers of aquatic beetles and bugs attracted to shiny black, white, red and yellow horizontal plastic sheets, we found that red and black reflectors are equally highly attractive to water insects, while yellow and white reflectors are unattractive. The reflection–polarization patterns of black, white, red and yellow cars were measured in the red, green and blue parts of the spectrum. In the blue and green, the degree of linear polarization p of light reflected from red and black cars is high and the direction of polarization of light reflected from red and black car roofs, bonnets and boots is nearly horizontal. Thus, the horizontal surfaces of red and black cars are highly attractive to red-blind polarotactic water insects. The p of light reflected from the horizontal surfaces of yellow and white cars is low and its direction of polarization is usually not horizontal. Consequently, yellow and white cars are unattractive to polarotactic water insects. The visual deception of aquatic insects by cars can be explained solely by the reflection–polarizational characteristics of the car paintwork.

Are Weeds Hitchhiking a Ride on Your Car? A Systematic Review of Seed Dispersal on Cars

Ansong, Michael; Pickering, Catherine
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 12/11/2013 EN
Relevância na Pesquisa
27.28%
When traveling in cars, we can unintentionally carry and disperse weed seed; but which species, and where are they a problem? To answer these questions, we systematically searched the scientific literature to identify all original research studies that assess seed transported by cars and listed the species with seed on/in cars. From the 13 studies that fit these criteria, we found 626 species from 75 families that have seed that can be dispersed by cars. Of these, 599 are listed as weeds in some part of the world, with 439 listed as invasive or naturalized alien species in one or more European countries, 248 are invasive/noxious weeds in North America, 370 are naturalized alien species in Australia, 167 are alien species in India, 77 are invasive species in China and 23 are declared weeds/invaders in South Africa. One hundred and one are classified as internationally important environmental weeds. Although most (487) were only recorded once, some species such as Chenopodium album, Poa pratensis and Trifolium repens were common among studies. Perennial graminoids seem to be favoured over annual graminoids while annual forbs are favoured over perennial forbs. Species characteristics including seed size and morphology and where the plants grew affected the probability that their seed was transported by cars. Seeds can be found in many different places on cars including under the chassis...

Hyperspectral and differential CARS microscopy for quantitative chemical imaging in human adipocytes

Di Napoli, Claudia; Pope, Iestyn; Masia, Francesco; Watson, Peter; Langbein, Wolfgang; Borri, Paola
Fonte: Optical Society of America Publicador: Optical Society of America
Tipo: Artigo de Revista Científica
Publicado em 02/04/2014 EN
Relevância na Pesquisa
27.24%
In this work, we demonstrate the applicability of coherent anti-Stokes Raman scattering (CARS) micro-spectroscopy for quantitative chemical imaging of saturated and unsaturated lipids in human stem-cell derived adipocytes. We compare dual-frequency/differential CARS (D-CARS), which enables rapid imaging and simple data analysis, with broadband hyperspectral CARS microscopy analyzed using an unsupervised phase-retrieval and factorization method recently developed by us for quantitative chemical image analysis. Measurements were taken in the vibrational fingerprint region (1200–2000/cm) and in the CH stretch region (2600–3300/cm) using a home-built CARS set-up which enables hyperspectral imaging with 10/cm resolution via spectral focussing from a single broadband 5 fs Ti:Sa laser source. Through a ratiometric analysis, both D-CARS and phase-retrieved hyperspectral CARS determine the concentration of unsaturated lipids with comparable accuracy in the fingerprint region, while in the CH stretch region D-CARS provides only a qualitative contrast owing to its non-linear behavior. When analyzing hyperspectral CARS images using the blind factorization into susceptibilities and concentrations of chemical components recently demonstrated by us...

Will Euro 6 reduce the NOx emissions of new diesel cars? - Insights from on-road tests with Portable Emissions Measurement Systems (PEMS)

WEISS MARTIN; BONNEL Pierre; KÜHLWEIN JÖRG; PROVENZA ALESSIO; LAMBRECHT Udo; ALESSANDRINI Stefano; CARRIERO Massimo; COLOMBO Rinaldo; FORNI Fausto; LANAPPE Gaston; LE LIJOUR Philippe; MANFREDI Urbano; MONTIGNY Francois; SCULATI Mirco
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Articles in Journals Formato: Online
ENG
Relevância na Pesquisa
27.26%
The nitrogen dioxide (NO2) pollution in urban areas of Europe can be partially attributed to the increasing market penetration of diesel cars that show higher distance-specific nitrogen oxides (NOx) emissions than gasoline cars. The on-road NOx emissions of diesel cars, furthermore, appear to exceed substantially applicable emissions standards. This observation raises concerns that the introduction of more stringent Euro 6 emissions standards in 2014 may not adequately reduce the distance-specific on-road NOx emissions of new diesel cars. We address the existing concerns by analyzing the gaseous emissions of one novel Euro 6 diesel car and six Euro 4-5 diesel cars with Portable Emissions Measurement Systems (PEMS). We find that the average on-road NOx emissions of the Euro 6 car (0.21 ± 0.09 gram per kilometer [g/km]) are considerably lower than those of the Euro 4 cars (0.76 ± 0.12 g/km) and the Euro 5 cars (0.71 ± 0.30 g/km). The selective catalytic reduction (SCR) system of the Euro 6 diesel car is suitable to limit NOx emissions during real-world on-road driving. Still, all tested cars, including the Euro 6 diesel car, exceed their NOx emissions standards on the road by 260 ±130%. This finding suggests that the current type-approval procedure does not adequately capture the on-road NOx emissions of diesel cars. By introducing a complementary emissions test procedure that covers a wide range of normal operating conditions...

Theoretical Investigation of Material Properties Affecting Coherent Anti-Stokes Raman Scattering Microendoscopy

Satira, Zachary
Fonte: Universidade Rice Publicador: Universidade Rice
Relevância na Pesquisa
27.24%
Physicians in clinical settings are constantly seeking label-free imaging modalities with superior sensitivity and resolution. Coherent anti-Stokes Raman scattering (CARS) has demonstrated great clinical potential, but complicated optics and poor conversion efficiency of CARS signal photons has limited the use of endoscopic CARS. Optimization of optical systems for maximal signal collection for rapid, low noise endoscopic imaging is essential. In vivo CARS imaging collects a large backscattered signal from forward CARS, obscuring structures with dimensions similar to the excitation wavelength. This is the first model to accurately determine the effect of scattering in multiple tissue types on CARS imaging. By characterizing the radial location of the backward CARS signal from sub-wavelength features and backscattered forward CARS signals from larger scatterers, methods are developed to collect both images simultaneously. Numerical methods are utilized to demonstrate how the focusing objective, focal depth, collection method, and object of interest impact CARS imaging.

Developing Single-Laser Sources for Multimodal Coherent Anti-Stokes Raman Scattering Microscopy

PEGORARO, ADRIAN FRANK
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
27.21%
Coherent anti-Stokes Raman scattering (CARS) microscopy has developed rapidly and is opening the door to new types of experiments. This work describes the development of new laser sources for CARS microscopy and their use for different applications. It is specifically focused on multimodal nonlinear optical microscopy—the simultaneous combination of different imaging techniques. This allows us to address a diverse range of applications, such as the study of biomaterials, fluid inclusions, atherosclerosis, hepatitis C infection in cells, and ice formation in cells. For these applications new laser sources are developed that allow for practical multimodal imaging. For example, it is shown that using a single Ti:sapphire oscillator with a photonic crystal fiber, it is possible to develop a versatile multimodal imaging system using optimally chirped laser pulses. This system can perform simultaneous two photon excited fluorescence, second harmonic generation, and CARS microscopy. The versatility of the system is further demonstrated by showing that it is possible to probe different Raman modes using CARS microscopy simply by changing a time delay between the excitation beams. Using optimally chirped pulses also enables further simplification of the laser system required by using a single fiber laser combined with nonlinear optical fibers to perform effective multimodal imaging. While these sources are useful for practical multimodal imaging...

Plan de mercadeo para la empresa Only Cars

Fonte: Universidad Autónoma de Occidente; Mercadeo y Negocios Internacionales Publicador: Universidad Autónoma de Occidente; Mercadeo y Negocios Internacionales
Tipo: Bachelor Thesis; Pasantía Formato: PDF
SPA
Relevância na Pesquisa
36.93%
Only Cars, empresa especializada en lámina y pintura, polarizados y películas de seguridad, porcenalizados y restauración de pintura, restauración general de vehículos antiguos, lo anterior la posiciona como una empresa muy competitiva y reconocida, y se pretende que su rentabilidad sea cada vez más alta, analizar y conocer quién es la competencia y cómo la maneja. La empresa en estos momentos se encuentra bien posicionada gracias a su esfuerzos y además los clientes la perciben como una empresa seria y confiable, gracias a esto ha logrado alcanzar y sobrepasar el punto de equilibrio. A diferencia de otras empresas, Only Cars se preocupa en la prestación de servicios para que los clientes se sientan satisfechos ya que prestan un buen servicio y excelente calidad a precios relativamente competitivos

Estrategias de mercadeo para impulsar la comercialización de carros eléctricos en bogotá; Marketing strategies to promote the commercialization of electric cars in bogota

Hennessey Lizcano, Alejandra; Pereira Silva, Jackson
Fonte: Universidad Militar Nueva Granada; Facultad de Ciencias Económicas; Especialización en Mercadeo de Servicios Publicador: Universidad Militar Nueva Granada; Facultad de Ciencias Económicas; Especialización en Mercadeo de Servicios
Tipo: bachelorThesis; Trabajo de grado Formato: pdf; pdf
SPA
Relevância na Pesquisa
36.79%
Este trabajo se realiza para analizar las ventajas y desventajas de introducir carros eléctricos en la ciudad de Bogotá, así como las diferentes estrategias de mercadeo que pueden ser implementadas para lograr su comercialización en el mercado colombiano, y el impacto que se generaría sobre el medio ambiente.; This work is performed to analyze the advantages and disadvantages of introducing electric cars in Bogotá city, also the different marketing strategies that can be implemented to achieve commercialization in the Colombian market, and the impact that would generate. environmental .

Will Electric Cars Transform the U.S. Market

Lee, Henry; Grant, Lovellette
Fonte: John F. Kennedy School of Government, Harvard University Publicador: John F. Kennedy School of Government, Harvard University
Tipo: Research Paper or Report
EN_US
Relevância na Pesquisa
36.79%
For the past forty years, United States Presidents have repeatedly called for a reduction in the country's dependence on fossil fuels in general and foreign oil specifically. Stronger efficiency standards and higher taxes on motor fuels are a step in this direction, but achieving even greater reductions in oil consumption will require changing the way Americans power their transportation system. Some officials advocate the electrification of the passenger vehicle fleet as a path to meeting this goal. The Obama administration has, for example, embraced a goal of having one million electric-powered vehicles on U.S. roads by 2015, while others proposed a medium-term goal where electric vehicles would consist of 20% of the passenger vehicle fleet by 2030—approximately 30 million electric vehicles. The technology itself is not in question—many of the global automobile companies are planning to sell plug-in hybrid electric vehicles (PHEVs) and/or battery electric vehicles (BEVs) by 2012. The key question is, will Americans buy them? The answer depends on four additional questions: 1. Is the cost of purchasing and operating an electric vehicle more or less expensive than the cost of a comparable conventional gasoline-powered vehicle? 2. Are the comparative costs likely to change over the next twenty years? 3. Do electric vehicles provide the same attributes as conventional cars...

Tobacco use and asking prices of used cars: prevalence, costs, and new opportunities for changing smoking behavior

Matt, Georg E; Romero, Romina; Ma, Debbie S; Quintana, Penelope JE; Hovell, Melbourne F; Donohue, Michael; Messer, Karen; Salem, Simon; Aguilar, Mauricio; Boland, Justin; Cullimore, Jennifer; Crane, Marissa; Junker, Jonathan; Tassinario, Peter; Timmermann
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 31/07/2008 EN
Relevância na Pesquisa
27.18%
Secondhand smoke (SHS) causes premature death and disease in children and adults, and the scientific evidence indicates that there is no risk-free level of exposure to SHS. Smoking tobacco in a car can pollute the microenvironment of the car with residual SHS, leaving telltale signs to potential buyers (e.g., odor, used ash tray). This study examined (a) the proportion of used cars sold in the private party market that may be polluted with tobacco smoke and (b) whether asking prices of smoker and nonsmoker cars differed for cars of otherwise equivalent value. A random sample of 1,642 private party sellers were interviewed by telephone, and content analyses of print advertisements were conducted. Findings indicate that 22% of used cars were advertised by smokers or had been smoked in during the previous year. Among nonsmokers, 94% did not allow smoking in their car during the past year. Only 33% of smokers had the same restrictions. The smoking status of the seller and tobacco use in the car were significantly (p < .01) associated with the asking price independent of a car's Kelley Blue Book value (KBB). Used nonsmoker cars were offered at a considerable premium above their KBB value (>11%) and above comparable smoker cars (7–9%). These findings suggest that community preferences are affecting the value of smoke-free cars. New directions for research...

Differential Imaging of Biological Structures with Doubly-resonant Coherent Anti-stokes Raman Scattering (CARS)

Weeks, Tyler J.; Huser, Thomas R.
Fonte: MyJove Corporation Publicador: MyJove Corporation
Tipo: Artigo de Revista Científica
Publicado em 17/10/2010 EN
Relevância na Pesquisa
27.24%
Coherent Raman imaging techniques have seen a dramatic increase in activity over the past decade due to their promise to enable label-free optical imaging with high molecular specificity 1. The sensitivity of these techniques, however, is many orders of magnitude weaker than fluorescence, requiring milli-molar molecular concentrations 1,2. Here, we describe a technique that can enable the detection of weak or low concentrations of Raman-active molecules by amplifying their signal with that obtained from strong or abundant Raman scatterers. The interaction of short pulsed lasers in a biological sample generates a variety of coherent Raman scattering signals, each of which carry unique chemical information about the sample. Typically, only one of these signals, e.g. Coherent Anti-stokes Raman scattering (CARS), is used to generate an image while the others are discarded. However, when these other signals, including 3-color CARS and four-wave mixing (FWM), are collected and compared to the CARS signal, otherwise difficult to detect information can be extracted 3. For example, doubly-resonant CARS (DR-CARS) is the result of the constructive interference between two resonant signals 4. We demonstrate how tuning of the three lasers required to produce DR-CARS signals to the 2845 cm-1 CH stretch vibration in lipids and the 2120 cm-1 CD stretching vibration of a deuterated molecule (e.g. deuterated sugars...

CARS untersuchung von energietransferprozessen am Na-H2- system

Cunha, Silvio Luiz Souza
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
DEU
Relevância na Pesquisa
27.31%
Nonadiabatic collisions between atoms and molecules have drawn a large amount of attention in theoretical and experimental studies. In particular, the transfer of electronic energy of an atom to the vibrational, rotational and translational energy of a diatomic molecule (also called electronic quenching) can be considered an important fundamental process of this type and is thus extensively investigated. We study the Na + 112 as a model collision system for experimental and theoretical reasons since ab initio potential surfaces are currently available, enabling comparison of experimental results with theoretical calculations. We apply a new experimental technique in the field of nonadiabatic processes to obtain a more detailed understanding of these energy transfer processes. We use Coherent Anti-Stokes Raman Spectroscopy (CARS) to measure directly the internai energy distribution of H2 molecules produced by quenching of Na in the first excited state (3 2P112). Although CARS has been used to detect 112 among other species, it has never been applied to gaseous mixtures with H2 and atomic or molecular sodium. Sodium with its low lying electronic states produces a strong nonresonant background that strongly reduces the sensitivity of CARS. With a new constructed apparatus a sensitivity for H2 of 1012 particles per cm3 and quantum state in the presence of ground state sodium was achieved and 1013 particles per cm3 and quantum state with excited sodium. The following results were obtained: 1. The absolute population of vibrational leveis up to v=3 has been obtained and was found to be extremly nonthermal. The state distribution is...

A non-intrusive measurement technique applying CARS for concentration measurement in a gas mixing flow

Yamamoto, Ken; Yamagata, Yuki; Moriya, Madoka; Kuriyama, Reiko; Sato, Yohei
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/08/2015
Relevância na Pesquisa
27.21%
Coherent anti-Stokes Raman scattering (CARS) microscope system was built and applied to a non-intrusive gas concentration measurement of a mixing flow in a millimeter-scale channel. Carbon dioxide and nitrogen were chosen as test fluids and CARS signals from the fluids were generated by adjusting the wavelengths of the Pump and the Stokes beams. The generated CARS signals, whose wavelengths are different from those of the Pump and the Stokes beams, were captured by an EM-CCD camera after filtering out the excitation beams. A calibration experiment was performed in order to confirm the applicability of the built-up CARS system by measuring the intensity of the CARS signal from known concentrations of the samples. After confirming that the measured CARS intensity was proportional to the second power of the concentrations as was theoretically predicted, the CARS intensities in the gas mixing flow channel were measured. Ten different measurement points were set and concentrations of both carbon dioxide and nitrogen at each point were obtained. Consequently, it was observed that the mixing of two fluids progressed as the measurement point moved downstream. The results show the applicability of CARS to the non-intrusive concentration measurement of gas flows without any preprocess such as gas absorption into liquid or solid.; Comment: 16 pages...

Equilibrium traffic flow of a mixture of cars with different properties

Šurda, Anton
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/08/2009
Relevância na Pesquisa
27.26%
Statistical mechanics of a disordered system of cars on a single-lane road is developed. Behaviour of cars is defined by conditional probability of car velocity depending on the distance and velocity of the car ahead. A system consisting of different cars is modelled by a system of two types of cars differing in maximal velocity or efficiency of brakes. Starting from conditional probabilities and using principle of maximum entropy, probability densities of car velocities and headways are calculated. It is shown that the first-order phase transition between free flow and congested traffic may be driven by number of fast cars in a system of slow cars, and, as a rule, admixture of cars of superior qualities does not increase but decreases the total flow. In the system of cars with poor brakes platoons of cars of the same velocity are formed. They are dissolved by a small addition of cars with good brakes. Application of principle of maximum entropy was justified by comparing the results with steady state properties of an equivalent kinetic model.; Comment: 17 pages, 11 figures