Experimental study of the effect of paint on embedded automotive antennas

In years have seen the advent of new types of automotive antennas, such as blade or 'shark-fin' antennas and conformal planar roof mounted antennas. In many cases it is desirable to paint these antennas to improve the appearance of the vehicle. In this communication we present an investigation of the effect that both metallic and non-metallic two-pack polyurethane paint has on a structure radiating at approximately 1.5 GHz (GPS Ll-band), with a particular emphasis on the impedance bandwidth and radiation performance

Fluorescence from a few electrons

Systems containing few Fermions (e.g., electrons) are of great current interest. Fluorescence occurs when electrons drop from one level to another without changing spin. Only electron gases in a state of equilibrium are considered. When the system may exchange electrons with a large reservoir, the electron-gas fluorescence is easily obtained from the well-known Fermi-Dirac distribution. But this is not so when the number of electrons in the system is prevented from varying, as is the case for isolated systems and for systems that are in thermal contact with electrical insulators such as diamond. Our accurate expressions rest on the assumption that single-electron energy levels are evenly spaced, and that energy coupling and spin coupling between electrons are small. These assumptions are shown to be realistic for many systems. Fluorescence from short, nearly isolated, quantum wires is predicted to drop abruptly in the visible, a result not predicted by the Fermi-Dirac distribution. Our exact formulas are based on restricted and unrestricted partitions of integers. The method is considerably simpler than the ones proposed earlier, which are based on second quantization and contour integration.Comment: 10 pages, 3 figures, RevTe

Recognizing Emotions in a Foreign Language

Expressions of basic emotions (joy, sadness, anger, fear, disgust) can be recognized pan-culturally from the face and it is assumed that these emotions can be recognized from a speaker's voice, regardless of an individual's culture or linguistic ability. Here, we compared how monolingual speakers of Argentine Spanish recognize basic emotions from pseudo-utterances ("nonsense speech") produced in their native language and in three foreign languages (English, German, Arabic). Results indicated that vocal expressions of basic emotions could be decoded in each language condition at accuracy levels exceeding chance, although Spanish listeners performed significantly better overall in their native language ("in-group advantage"). Our findings argue that the ability to understand vocally-expressed emotions in speech is partly independent of linguistic ability and involves universal principles, although this ability is also shaped by linguistic and cultural variables

The design and realization of uniplanar CPW fed PICA slot antennas

In modern wireless communication system design, antennas with wide impedance bandwidth are desirable for numerous reasons. An antenna with a wide impedance bandwidth may be used for transmission and reception of multiple narrowband services in a multi-purpose platform. Alternatively a single wideband service may be of interest for various radar and imaging applications, or for impulse based radio communications in the FCC ultra-wideband (UWB) regime from 3.1 GHz to 10.6 GHz

Study of temperature-growth interactions of entomopathogenic fungi with potential for control of Varroa destructor (Acari: Mesostigmata) using a nonlinear model of poikilotherm development

Aims: To investigate the thermal biology of entomopathogenic fungi being examined as potential microbial control agents of Varroa destructor , an ectoparasite of the European honey bee Apis mellifera . Methods and Results: Colony extension rates were measured at three temperatures (20, 30 and 35degreesC) for 41 isolates of entomopathogenic fungi. All of the isolates grew at 20 and 30degreesC but only 11 isolates grew at 35degreesC. Twenty-two isolates were then selected on the basis of appreciable growth at 30-35degreesC (the temperature range found within honey bee colonies) and/or infectivity to V. destructor , and their colony extension rates were measured at 10 temperatures (12.5-35degreesC). This data were then fitted to Schoolfield et al . [J Theor Biol (1981)88:719-731] re-formulation of the Sharpe and DeMichele [J Theor Biol (1977)64:649-670] model of poikilotherm development. Overall, this model accounted for 87.6-93.9% of the data variance. Eleven isolates exhibited growth above 35degreesC. The optimum temperatures for extension rate ranged from 22.9 to 31.2degreesC. Only three isolates exhibited temperature optima above 30degreesC. The super-optimum temperatures (temperature above the optimum at which the colony extension rate was 10% of the maximum rate) ranged from 31.9 to 43.2degreesC. Conclusions: The thermal requirements of the isolates examined against V. destructor are well matched to the temperatures in the broodless areas of honey bee colonies, and a proportion of isolates, should also be able to function within drone brood areas. Significance and Impact of the Study: Potential exists for the control of V. destructor with entomopathogenic fungi in honey bee colonies. The methods employed in this study could be utilized in the selection of isolates for microbial control prior to screening for infectivity and could help in predicting the activity of a fungal control agent of V. destructor under fluctuating temperature conditions

Parametric Evaluation of Communication Devices in Smart Composite Structures

This paper reports on some of the rheological results of the selected composite materials. The base material components comprise unsaturated polyester (uPE) reinforced with randomly distributed short strands of fibreglass (E type). This material is commonly known as sheet moulding compound (SMC) and is currently used in the automotive industry for different applications. This work will further look into t he parameters involved in the processing of the SMC with respect to its visco-elastic behaviour. These parameters involve viscosity, elastic and viscous modulus with respect to the processing temperature. This paper reports on some preliminary results of material processing parameters such as pressures, temperatures, cure times and volume fractions of resins, fillers and reinforcing materials. Also included is an evaluation of the electrical properties of different grades of SMC as a precursor to the encapsulation of a microstrip antenna within the material