398 research outputs found

    Communication and Powering Scheme for Wireless and Battery-Less Measurement

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    The paper presents solution for wireless and battery-less measurement in the enclosed areas. The principle is based on passive RFID, nevertheless this paper is focused on high power-demanding applications such as MEMS accelerometers, gas sensors, piezoresistive strain gauges, etc. Standard FRID communication scheme (sensing the input current change on the primary side) cannot be used in this case, because the communication channel is overloaded by the high power load. Paper presents possible solution which is based on the dual frequency scheme – one frequency for powering and other for the communication. This is ensuring capability for measurement up to several centimeters on the frequency bands 125 kHz and 375 kHz. It can be suitable for continual measurement in isolated systems such as the rotating objects, concrete walls, enclosed plastic barrels, high temperature chambers etc

    3D Energy Harvester Evaluation

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    This paper discusses the characterization and evaluation of an MEMS based electrostatic generator, a part of the power supply unit of the self-powered microsystem[1,2,3]. The designed generator is based on electrostatic converter and uses the principle of conversion of non-electric energy into electrical energy by periodical modification of gap between electrodes of a capacitor [4]. The structure is designed and modeled as three-dimensional silicon based MEMS. Innovative approach involving the achievement of very low resonant frequency of the structure (about 100Hz) by usage of modified long cantilever spring design, minimum area of the chip, 3D work mode, the ability to be tuned to reach desired parameters, proves promising directions of possible further development

    Design and Fabrication of 3D Electrostatic Energy Harvester

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    This paper discusses the design of an electrostatic generator, power supply component of the self-powered microsystem, which is able to provide enough energy to power smart sensor chains or if necessary also other electronic monitoring devices. One of the requirements for this analyzer is the mobility, so designing the power supply expects use of an alternative way of getting electricity to power the device, rather than rely on periodic supply of external energy in the form of charging batteries, etc. In this case the most suitable method to use is so-called energy harvesting – a way how to gather energy. This uses the principle of non-electric conversion of energy into electrical energy in the form of converters. The present study describes the topology design of such structures of electrostatic generator. Structure is designed and modeled as a three-dimensional silicon based MEMS. Innovative approach involving the achievement of very low resonant frequency of the structure, while the minimum area of the chip, the ability to work in all 3 axes of coordinate system and ability to be tuned to reach desired parameters proves promising directions of possible further development of this issue. The work includes simulation of electro-mechanical and electrical properties of the structure, description of its behavior in different operating modes and phases of activity. Simulation results were compared with measured values of the produced prototype chip. These results can suggest possible modifications to the proposed structure for further optimization and application environment adaptation

    Design and Modeling of Micromechanical GaAs based Hot Plate for Gas Sensors

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    For modern Gas sensors, high sensitivity and low power are expected. This paper discusses design, simulation and fabrication of new Micromachined Thermal Converters (MTCs) based on GaAs developed for Gas sensors. Metal oxide gas sensors generally work in high temperature mode that is required for chemical reactions to be performed between molecules of the specified gas and the surface of sensing material. There is a low power consumption required to obtain the operation temperatures in the range of 200 to 500 oC. High thermal isolation of these devices solves consumption problem and can be made by designing of free standing micromechanical hot plates. Mechanical stability and a fast thermal response are especially significant parameters that can not be neglected. These characteristics can be achieved with new concept of GaAs thermal converter.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

    The Red Road approach to healing as used in Native American adolescent addiction treatment

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    Traditional treatment programs have not worked with Native Americans. Instead, programs designed to be culturally sensitive are needed (Burn, 1992). In this paper, the author will explore the specific theory of the Red Road approach as used in Native American adolescent substance abuse treatment facilities. The Red Road approach is practical in its psychological application at the same time that it incorporates and encourages the spiritual beliefs which are a major part of the philosophy of most Native Americans (Black Elk & Lyon, 1991). As Black Elk and Lyons (1991) noted, even Native Americans who no longer practice their ancestral religious beliefs are often still exposed to these ways, as they are almost inevitably taught spirituality as part of their identity

    High Power Solid State Retrofit Lamp Thermal Characterization and Modeling

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    Thermal and thermo-mechanical modeling and characterization of solid state lightening (SSL) retrofit LED lamp are presented in this paper. Paramount importance is to design SSL lamps for reliability, in which thermal and thermo-mechanical aspects are key points. The main goal is to get a precise 3D thermal lamp model for further thermal optimization. Simulations are performed with ANSYS and CoventorWare software tools to compere different simulation approaches. Simulated thermal distribution has been validated with thermal measurement on a commercial 8W LED lamp. Materials parametric study has been carried out to discover problematic parts for heat transfer from power LEDs to ambient and future solutions are proposed. The objectives are to predict the thermal management by simulation of LED lamp, get more understanding in the effect of lamp shape and used materials in order to design more effective LED lamps and predict light quality, life time and reliability

    Time to Get in the Game: Opportunities for More Involvement in Sport-Related Concussion Management

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    Many college athletes who have a sport-related concussion experience changes in cognitive-communication abilities. Unfortunately, nearly half of all sport-related concussions go unreported. Information on why collegiate athletes report or conceal their symptoms is important for improving reporting rates and increasing athletes’ access to services for cognitive-communication impairments. This study examined whether changes in cognitive-communication abilities affected college athlete’s intentions to report a sport-related concussion. Findings showed that approximately two-thirds of the college student-athletes who participated in the research were unlikely to report that they had a sport-related head injury. The study found that participants’ concerns for cognitive-communication deficits differentiated student-athletes who were more likely to report an injury from those who were less likely. This study has important clinical implications for increasing awareness and knowledge about the sequelae of sport-related concussion and the valuable role that rehabilitation specialists, such as speech-language pathologists (SLPs), can play in concussion management and prevention

    Diffusive behavior for randomly kicked Newtonian particles in a spatially periodic medium

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    We prove a central limit theorem for the momentum distribution of a particle undergoing an unbiased spatially periodic random forcing at exponentially distributed times without friction. The start is a linear Boltzmann equation for the phase space density, where the average energy of the particle grows linearly in time. Rescaling time, the momentum converges to a Brownian motion, and the position is its time-integral showing superdiffusive scaling with time t3/2t^{3/2}. The analysis has two parts: (1) to show that the particle spends most of its time at high energy, where the spatial environment is practically invisible; (2) to treat the low energy incursions where the motion is dominated by the deterministic force, with potential drift but where symmetry arguments cancel the ballistic behavior.Comment: 55 pages. Some typos corrected from previous versio

    Uniwersytet Trzeciego Wieku: doświadczenie Ukrainy

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    W artykule zaprezentowano doświadczenie nauczania ludzi w starszym wieku na Ukrainie. Zarysowano konceptualne przepisy organizacji procesu edukacyjnego na Uniwersytecie Trzeciego Wieku. Wyjaśniono zasady nauczania ludzi w starszym wieku. Słowa kluczowe: edukacja i nauczanie ludzi w starszym wieku, UniwersytetTrzeciego Wieku, zadania, treść, formy, metody, cele nauczania ludzi w starszym wieku. The article presents the experience of studies of people years old in Ukraine. Conceptual positions of organization of educational process are outlined in University of the third age. Principles of studies of people are exposed years old

    Effect of light emitted by diodes on growth and pigment content of black currant plantlets in vitro

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    The effects of cool white, natural white, and warm white lights, which have a continuous spectrum throughout the region of surfactant, and blue-red light spectrum on in vitro growth and development of black currant (Ribes nigrum L.) was studied. It was demonstrated that the spectral composition of light affected length and fresh mass of shoots and roots as well as concentrations of chlorophylls, carotenoids, and anthocyanins. The plants grown under warm white light had the longest shoots (2.5 ± 0.2 cm) and fresh mass of shoots (166 ± 12 mg) and roots (80 ± 16 mg) relatively to оne’s grown under other light types. Under blue-red and warm white lights black currant leaves possessed the highest concentrations of chlorophyll a (2.66 ± 0.31 and 2.17 ± 0.14 µmol·gwm-1, respectively), chlorophyll b (1.15 ± 0.15 and 0.87± 0.05 µmol·gwm-1), carotenoids (0.89 ± 0.09 and 0.78 ± 0.05 µmol·gwm-1, respectively) and anthocyanins (1.37 ± 0.20 and 1.09 ± 0.05 µmol·gwm-1, respectively). Thus, blue-red (B:R = 1:4) and warm white lights may be used as an alternative light source for upland black currant culture systems
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