992 resultados para Millimeter waves


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According to the Intergovernmental Panel on Climate Change the buildings sector has the largest mitigation potential for CO2 emissions. Especially in office buildings, where internal heat loads and a relatively high occupant density occur at the same time with solar heat gains, overheating has become a common problem. In Europe the adaptive thermal comfort model according to EN 15251 provides a method to evaluate thermal comfort in naturally ventilated buildings. However, especially in the context of the climate change and the occurrence of heat waves within the last decade, the question arises, how thermal comfort can be maintained without additional cooling, especially in warm climates. In this paper a parametric study for a typical cellular naturally ventilated office room has been conducted, using the building simulation software EnergyPlus. It is based on the Mediterranean climate of Athens, Greece. Adaptive thermal comfort is evaluated according to EN 15251. Variations refer to different building design priorities, and they consider the variability of occupant behaviour and internal heat loads by using an ideal and worst case scenario. The influence of heat waves is considered by comparing measured temperatures for an average and an exceptionally hot year within the last decade. Since the use of building controls for shading affects thermal as well as visual comfort, daylighting and view are evaluated as well. Conclusions are drawn regarding the influence and interaction of building design, occupants and heat waves on comfort and greenhouse gas emissions in naturally ventilated offices, and related optimisation potential.

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Alien Radio Waves SFX is a sound effect on a synthesizer that could be mistaken for alien radio waves.

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Efficient markets are commonly defined as ones that do not allow investors to earn above-average returns without accepting above-average risk. In a traditional framework, where investors are rational and there are no frictions, the efficient market hypothesis (EMH) states that a security's price reflects its fundamental value, which is the sum of its discounted expected future cash flows. Put simply, under the EMH, securities are "rightly priced." Through this study, the author finds that while the EMH has been widely accepted for decades among academics, practitioners and regulators still appear to be unconvinced. From a behavioral perspective, the author shows that human psychology and sentiment factors can account for some discrepancies in financial markets. He also finds evidence of limited arbitrage being risky and costly and, hence, impeding the ability of investors to take advantage of profitable opportunities. This study provides an extensive analysis of the critical discussions surrounding the EMH and deepens and strengthens the understanding of the EMH, as well as the arguments for and against.

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This article is the second of a two-part series on the efficient market hypothesis corporate event waves. The ideas of market efficiency, or rational theory, and the behavioral hypothesis have been extensively used to explain the modern phenomena of corporate event waves. Some studies investigate the patterns of corporate events from a behavioral finance perspective and suggest that corporate announcement waves are driven by investor sentiment. Baker and Wurgler examine equity market timing as an aspect of real corporate financial policy. Sentiment can also explain IPO waves. Post-announcement returns and IPO volume are positively correlated to firms' capital demands and the level of investor optimism. Helwge and Liang examine the IPO cycles from hot to cold markets from 1975 to 2000. Corporate e vent wave scan also be explained by the neoclassical efficiency hypothesis, proposing that business cycle fluctuations and economic conditions drive firms' decisions on financing transactions.

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 The purpose of this paper is to provide a conceptual framework surrounding the typology of environmental sustainability efforts made within the sport industry. We draw from multiple theoretical frameworks (i.e. institutional theory and diffusion of innovation) to understand the increased similarities of environmental sustainability efforts through organizational learning as environmental sustainability efforts become more purposeful and sophisticated across the sport industry. The paper uses examples from various sport organizations and leagues to classify the efforts of sport organizations into waves of sport environmental sustainability efforts and important implications arising from them.

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This position paper argues that at this time of Mexico’s ongoing big transformation, legal educators and researchers in Mexico need to pay greater attention to international economic law, and that a renewal and perhaps some re-orientation of the approach to teaching international economic law, could provide significant contributions to and shape and support both the objectives and outcomes of reform in Mexico. International Economic Law courses and research can be made more useful, not only for students themselves, but also for their contribution towards the role that academics, lawyers, and other epistemic communities need to play in the political, economic and social evolution that is accelerating in Mexico.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This paper presents an experimental technique for structural health monitoring (SHM) based on Lamb waves approach in an aluminum plate using piezoelectric material as actuators and sensors. Lamb waves are a form of elastic perturbation that remains guided between two parallel free surfaces, such as the upper and lower surfaces of a plate, beam or shelf. Lamb waves are formed when the actuator excites the surface of the structure with a pulse after receiving a signal. Two PZTs were placed in the plate surface and one of them was used to send a predefined wave through the structure. Thus, the other PZT (adjacent) becomes the sensor. Using this methodology, this paper presents one case of damage detection considering the aluminum plate in the free-free-free-free boundary condition. The damage was simulated by adding additional mass on the plate. It is proposed two damage detection indexes obtained from the experimental signal, involving the Fast Fourier Transform (FFT) and the power spectral density (PSD) that were computed using the output signal. The results show the viability of the presented methodology to damage detection in smart structures

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The purpose of the work is to study the existence and nonexistence of shock wave solutions for the Burger equations. The study is developed in the context of Colombeau's theory of generalized functions (GFs). This study uses the equality in the strict sense and the weak equality of GFs. The shock wave solutions are given in terms of GFs that have the Heaviside function, in x and ( x, t) variables, as macroscopic aspect. This means that solutions are sought in the form of sequences of regularizations to the Heaviside function, in R-n and R-n x R, in the distributional limit sense.