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Many studies report an association between outdoor ambient weather and health. Outdoor conditions may be a poor indicator of personal exposure because people spend most of their time indoors. Few studies have examined how indoor conditions relate to outdoor ambient weather. The average indoor temperature, apparent temperature, relative humidity (RH), and absolute humidity (AH) measured in 16 homes in Greater Boston, Massachusetts, from May 2011 to April 2012 was compared to measurements taken at Boston Logan airport. The relationship between indoor and outdoor temperatures is nonlinear. At warmer outdoor temperatures, there is a strong correlation between indoor and outdoor temperature (Pearson correlation coefficient, = 0.91, slope, β = 0.41), but at cooler temperatures, the association is weak (= 0.40, β = 0.04). Results were similar for outdoor apparent temperature. The relationships were linear for RH and AH. The correlation for RH was modest (= 0.55, β = 0.39). Absolute humidity exhibited the strongest indoor‐to‐outdoor correlation (= 0.96, β = 0.69). Indoor and outdoor temperatures correlate well only at warmer outdoor temperatures. Outdoor RH is a poor indicator of indoor RH, while indoor AH has a strong correlation with outdoor AH year‐round.  相似文献   
213.
Multirotors, among all aerial vehicles, are fundamental instruments in many situations, i.e. video recording of sport events, leisure, environmental monitoring before or after a disaster. In particular, in the context of environmental monitoring, the possibility of following a predetermined path while avoiding obstacles is extremely relevant. In this work, we propose a novel method for path definition in presence of obstacles, which describes a curve as the intersection of two surfaces. The planner, based on that path definition along with a Cascaded control architecture and utilizing a nonlinear control technique for both control loops (position and attitude), creates a framework to manipulate the multicopters’ behaviors. The method is demonstrated to be able to generate a safe path taking into account obstacles perceived in real-time and avoids collisions. These algorithms are embedded in a software package to control the flight of a fully autonomous AscTec Firefly hexacopter with two cameras and onboard processing capabilities.  相似文献   
214.
The use of graphene to bridge TiO2 particles in the photoanode of dye‐sensitized solar cell for reduced electrical resistance has been investigated. The difficulty in dispersing graphene in TiO2 paste was overcome by first dispersing graphene oxide (GO) into the TiO2 paste. The GO was then reduced to graphene after the sintering of TiO2. This is shown through transmission electron microscopy and X‐ray photoelectron spectroscopy analysis. Cell performance was evaluated using a solar simulator, incident photon to electron conversion efficiency, intensity modulated photocurrent/photovoltage spectroscopy under blue light, and electrochemical impedance spectroscopy. Depending on the amount of graphene in the photoanode, the cell performance was enhanced to different degrees. A maximum increase of 11.4% in the cell efficiency has been obtained. In particular, the inclusion of graphene has reduced the electron diffusion time by as much as 23.4%, i.e. from 4.74 to 3.63 ms and increased the electron lifetime by as much as 42.3%, i.e. from 19.58 to 27.85 ms. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
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This paper describes a new, modified generalized Preisach model for actuators that have severe dead-zone hysteresis, which is mainly observed in rotary SMA actuators. Along with the Preisach model, a new approach of hysteresis modeling and parameter identification using genetic algorithm was proposed. This modeling method achieved significant improvements in both accuracy and computation time. The proposed approach is general; therefore, it can be applied to identify any type of hysteresis. To demonstrate the efficiency of the proposed model, experimental results on hysteresis identification of Rotary SMA Actuator and performance of inverse hysteresis openloop controller are provided and compared.  相似文献   
217.
We theoretically analyze nanowire-based hybrid plasmonic nanocavities on thin substrates at visible wavelengths. In the presence of thin suspended substrates, the hybrid plasmonic modes, formed by the coupling between a metal nanowire and a dielectric nanowire with optical gain, exhibit negligible substrate-mediated characteristics and overlap better with the gain region. Consequently, the confinement factor of the guided hybrid modes is enhanced by more than 42%. However, the presence of significant mirror loss remains the main challenge to lasing. By adding silver coatings with a sufficient thickness range on the two end facets, we show that the reflectivity is substantially enhanced to above 50%. For a coating thickness of 50 nm and cavity length of about 4 μm, the quality factor is above 100.  相似文献   
218.
The literature on the relationship between the degree of multinationality (M) and performance (P) in the context of multinational enterprises (MNEs) has attracted a large volume of research in the past 50 years. Yet, the theoretical foundations and the empirical conclusions concerning the nature of M–P relationship vary greatly, thus call for a critical review and assessment. We examine 135 articles in 39 leading scholarly journals and classic books published during the period 1960–2015. We use an inductive approach and a qualitative content analysis methodology for our comprehensive and critical review of the literature. We incorporate international business, finance, and accounting perspectives in our analysis. We review the conceptualization and measurement of M, P, the findings on M–P relationships, methodologies, and geographic focus. We identify six key inconsistencies in the existing research, which cause ambiguity in the relevant findings. We make eight recommendations for future research to address these inconsistencies. Thus, our study contributes to the central debate in this research field.  相似文献   
219.
The preparation of thioethers by S-alkylation of various thiols with alkyl halides under solvent-free reaction conditions using potassium fluoride on alumina (KF/Al2O3) as a solid catalyst has been investigated in detail with respect to three different modes of reaction activation (ultrasound irradiation, microwave irradiation, and conventional heating) for obtaining maximum yield of the thioether. The importance of KF/Al2O3 as a particularly efficient catalyst was corroborated for all three modes of reaction activation, although the reaction time was found to be strongly dependent on the mode of activation. The yield of the thioethers was also found to depend on the amount of the solid catalyst relative to the equimolar amounts of the two reactants.  相似文献   
220.
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