1,891 research outputs found

    Characterizing the thermal efficiency of thermoelectric modules

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    Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009."June 2009." Cataloged from PDF version of thesis.Includes bibliographical references (p. 22).An experimental setup was designed and utilized to measure the thermoelectric properties as functions of temperature of a commercially available, bismuth telluride thermoelectric module. Thermoelectric modules are solid state semiconducting devices that act reversibly as both a heat pump and a power generator. The experimental setup encased the modules in an insulating container and thermal power was provided by a variable power cartridge heater, using type-K thermocouples to measure the temperature difference across the module. The measured parameters were compared against published data on a similar type of module. The thermal conductivity was measured within 21% of the accepted value on average, the Seebeck coefficient within 16%, the figure of merit within a factor two, and the thermal efficiency within 20% for low [delta]T of less than 25°C.by Samuel S. Phillips.S.B

    The Incredible Peanut

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    Fourth Circuit: The Judicial Council\u27s Review on the Need for a Gender Bias Study

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    In 1993, the Women Judges Fund for Justice, the National Association of Women Judges, and the National Center for State Courts, sponsored a four-day conference (March 18-21) in Williamsburg, Virginia, entitled Second National Conference on Gender Bias in the Courts: Focus on Follow-up. Then Chief Circuit Judge Sam J. Ervin, III, designated the Deputy Circuit Executive to attend the conference on behalf of the Fourth Circuit. The Deputy also attended, along with a Fourth Circuit U.S. Magistrate Judge (now a U.S. District Judge), the Federal Judicial Center Gender Bias Task Force Workshop in Washington, D.C. (August 5-6, 1993)

    Studies of Respiratory Rhythm Generation Maintained in Organotypic Slice Cultures

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    Breathing is an important rhythmic motor behavior whose underlying neural mechanisms can be studied in vitro. The study of breathing rhythms in vitro has depended upon reduced preparations of the brainstem that both retain respiratory-active neuronal populations and spontaneously generate respiratory-related motor output from cranial and spinal motor nerves. Brainstem-spinal cord en bloc preparations and transverse medullary slices of the brainstem have greatly improved the ability of researchers to experimentally access and thus characterize interneurons important in respiratory rhythmogenesis. These existing in vitro preparations are, however, not without their limitations. For example, the window of time within which experiments may be conducted is limited to several hours. Moreover, these preparations are poorly suited for studying subcellular ion channel distributions and synaptic integration in dendrites of rhythmically active respiratory interneurons because of tortuous tissue properties in slices and en bloc, which limits imaging approaches. Therefore, there is a need for an alternative experimental approach. Acute transverse slices of the medulla containing the preBötzinger complex (preBötC) have been exploited for the last 25 years as a model to study the neural basis of inspiratory rhythm generation. Here we transduce such preparations into a novel organotypic slice culture that retains bilaterally synchronized rhythmic activity for up to four weeks in vitro. Properties of this culture model of inspiratory rhythm are compared to analogous acute slice preparations and the rhythm is confirmed to be generated by neurons with similar electrophysiological and pharmacological properties. The improved optical environment of the cultured brain tissue permits detailed quantitative calcium imaging experiments, which are subsequently used to examine the subcellular distribution of a transient potassium current, IA, in rhythmically active preBötC interneurons. IA is found on the dendrites of these rhythmically active neurons, where it influences the electrotonic properties of dendrites and has the ability to counteract depolarizing inputs, such as post-synaptic excitatory potentials, that are temporally sparse in their occurrence (i.e., do not summate). These results suggest that excitatory input can be transiently inhibited by IA prior to its steady-state inactivation, which would occur as temporally and spatially summating synaptic inputs cause persistent depolarization. Thus, rhythmically active interneurons are equipped to appropriately integrate the activity state of the inspiratory network, inhibiting spurious inputs and yet yielding to synaptic inputs that summate, which thus coordinates the orderly recruitment of network constituents for rhythmic inspiratory bursts. In sum, the work presented here demonstrates the viability and potential usefulness of a new experimental model of respiratory rhythm generation, and further leverages its advantages to answer questions about dendritic synaptic integration that could not previously be addressed in the acute slice models of respiration. We argue that this new organotypic slice culture will have widespread applicability in studies of respiratory rhythm generation

    Torts - Wife\u27s Right to Sue Husband

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    Torts - Wife\u27s Right to Sue Husband

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