Solid state bistable power switch

Tin and copper provide high current and switching time capabilities for high-current resettable fuses. They show the best performance for trip current and degree of reliability, and have low coefficients of thermal expansion

Solid state bistable power switch study

Feasibility of transforming solid state switches into high current resettable fuse

On the possibility of a warped disc origin of the inclined stellar discs at the Galactic Centre

(Abridged) The Galactic Center (GC) hosts a population of young stars some of which seem to form mutually inclined discs of clockwise and counter clockwise rotating stars. We present a warped disc origin scenario for these stars assuming that an initially flat accretion disc becomes warped due to the Pringle instability, or due to Bardeen-Petterson effect, before it fragments to stars. We show that this is plausible if the star formation efficiency $\epsilon_{SF} \lesssim 1$, and the viscosity parameter $\alpha \sim 0.1$. After fragmentation, we model the disc as a collection of concentric, circular, mutually tilted rings, and construct warped disc models for mass ratios and other parameters relevant to the GC environment, but also for more massive discs. We take into account the disc's self-gravity and the torques exerted by a surrounding star cluster. We show that a self-gravitating low-mass disc ($M_d / M_{bh} \sim 0.001$) precesses in integrity in the life-time of the stars, but precesses freely when the torques from a non-spherical cluster are included. An intermediate-mass disc ($M_d / M_{bh} \sim 0.01$) breaks into pieces which precess independently in the self-gravity-only case, and become disrupted in the presence of the star cluster torques. For a high-mass disc ($M_d / M_{bh} \sim 0.1$) the evolution is dominated by self-gravity and the disc is broken but not dissolved. The time-scale after which the disc breaks scales almost linearly with ($M_d / M_{bh}$) for self-gravitating models. Typical values are longer than the age of the stars for a low mass disc, and are in the range $\sim 8 \times 10^4-10^5$ yr for high and intermediate-mass discs respectively. None of these models explain the rotation properties of the two GC discs, but a comparison of them with the clockwise disc shows that the lowest mass model in a spherical star cluster matches the data best.Comment: 16 pages, 19 figures, abstract abridged to meet arXiv requirements. Accepted for publication in MNRA

Personality Types Among Athletic Trainers

This research study analyzed the personality types among the Athletic Training (AT) profession. With no research present in the field of Athletic Training, research from similar fields like Physical Therapy, and Occupational Therapy were referenced throughout the research process. Throughout the literature review process it was observed that previous researchers used the Meyers-Briggs Type Indicator (MBTI) assessment tool to identify personality types. A MBTI assessment tool was used to identify personality types among the participants, and a demographics survey comprised of nine questions was used to determine participant’s experience in the Athletic Training profession. After reviewing previous studies from other professions that closely resembled Athletic Training, the researcher hypothesized that AT’s would possess extroverted-sensing-thinking-judgement (ESTJ) personality biases. The target demographic for the study was NCAA Division III Athletic Trainers in Ohio. The survey was sent to 99 Athletic Trainers that practiced at the Division III level. A second round was sent halfway through the month long data collection process. Invitations to participate were sent at the beginning of the month, and again at the halfway point of the month. The nominal data was then analyzed by the researcher for a trend in responses. Results identified that AT’s possessed extroverted-sensing-feeling-judgement (ESFJ) personality biases. They also had a high amount of introverted-sensing-feeling-judgement (ISFJ) personality biases. Another interesting finding showed that 55 percent of personality types reported were introverted in nature when compared to 45 percent being extroverted. It was concluded that Athletic Trainers have a high amount of sensing-feeling-judging personality biases and are also more introverted in nature when compared to other professions like Physical Therapy and Occupational Therapy

Influence of Wind Farms on Electrical Energy Quality

Tato práce se zabývá vlivy větrných elektráren na kvalitu elektrické energie. Cílem práce bylo pomocí modelu konkrétní sítě vyhodnotit vliv těchto zdrojů při velkém zastoupení v energetickém mixu. První část práce byla věnována prezentaci výrobců větrných elektráren a jejich zastoupení na světovém a evropském trhu. Zároveň byly představeny nové technologie využívání větrné energie. Druhá část se zabývá způsoby vlivu větrných elektráren na kvalitu elektrické energie. V této části byl pomocí počítačového programu GLF vytvořen model sítě, do kterého byly připojovány větrné parky. Pomocí tohoto modelu byla zpracována analýza lokálních vlivů větrných elektráren na kvalitu elektrické energie. V poslední části byl zhodnocen vliv integrace větrných elektráren na cenu elektrické energie a náklady na stavbu a provoz, včetně prognózy do budoucna.This thesis is occupied by influences of wind farms on electrical energy quality. Object of thesis was analyse influence of these power plants in a large of number. The first part was attended to presentation of wind turbines producers and their agency on worldwide and European market. At the same time were introduced new technologies of wind power generate. The second part is occupied by influence of wind farms on electrical energy quality. In this part was created model of feed system by GLF software and wind farms were connected into it. By the help of this model was run analyze of local influences of wind power plants on electrical energy quality. In last part was assessed influence of wind power plants feed system integration on electrical energy price, build and operating costs, including the prognosis to the future.