497 research outputs found

    Commissioning results of the HZB Quadrupole Resonator

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    Recent cavity results with niobium have demonstrated the necessity of a good understanding of both the BCS and residual resistance. For a complete picture and comparison with theory, it is essential that one can measure the RF properties as a function of field, temperature, frequency and ambient magnetic field. Standard cavity measurements are limited in their ability to change all parameters freely and in a controlled manner. On the other hand, most sample measurement setups operate at fairly high frequency, where the surface resistance is always BCS dominated. The quadrupole resonator, originally developed at CERN, is ideally suited for characterization of samples at typical cavity RF frequencies. We report on a modified version of the QPR with improved RF figures of merit for high field operation. Experimental challenges in the commissioning run and alternate designs for simpler sample changes are shown alongside measurement results of a large grain niobium sampl

    Time-varied daylighting performance to enable a goal-driven design process

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 140-152).Due to the overwhelming number of decisions to be made during early stage design, there is a need for intuitive methods to communicate data so that it is quickly and easily understood by the designer. In daylighting analysis, research has been moving towards dynamic daylighting metrics, which include both annual performance indicators and local climate conditions. Temporally-based graphics are one method of annual data display which shows great promise for use in the early design stage. Not only can temporal data be easily connected to time-dependent environmental variables like weather and solar angle, but non-spatial quantities related to solar heat gain can be compared on the same terms with spatial quantities like illuminance. This thesis demonstrates methods for quickly calculating annual data sets for which temporal maps are the intended display format. Metrics are then developed in order to display goal-based performance information for an entire area of interest on a single temporal map. This process is demonstrated first by reducing the number of simulations necessary to produce reliable annual illuminance data, the results of which are compiled into a metric based on a user-given illuminance range, known as Acceptable Illuminance Extent (AIE). Similarly, a geometry-based glare approximation method is developed and validated for quick annual calculations of Daylight Glare Probability, and the results are condensed to a single number representative of glare perception within the model, known as Glare Avoidance Extent (GAE).(cont.) Finally, a simple solar heat gain indicator is demonstrated using the Balance Point calculation method and the metric Solar Heat Scarcity/Surplus (SHS) is used to convey the urgency of allowing more direct solar gain or shading it. This thesis is part of the Lightsolve project, which aims to specifically address the needs of the architect during early design stages. Specifically, Lightsolve aims to produce fast, unique design analyses, based on local annual climate data with reasonably accurate and intuitive outputs to promote good decision-making. Such resources could enable a desirable shift in schematic stage design practices and move daylighting analysis one step closer to achieving "best practice" recognition.by Siân Alexandra Kleindienst.Ph.D

    Observer design for a nonlinear heat equation: Application to semiconductor wafer processing

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    In this paper, the problem of observer design for a class of 1D nonlinear heat equations with pointwise in-domain temperature measurements is addressed. A pointwise measurement injection observer is designed and the robust convergence of its estimation error in presence of bounded distributed perturbations is established by verifying input-to-state stability. The obtained convergence conditions express the underlying interplay between heat conduction and radiation and include specific dependencies on the sensor locations which are the main degrees of freedom in the design approach. The theoretical results are experimentally validated on a semiconductor wafer processing unit

    RIM-Binding Protein 2 organizes Ca2+channel topography and regulates release probability and vesicle replenishment at a fast central synapse

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    RIM-Binding Protein 2 (RIM-BP2) is a multi-domain protein of the presynaptic active zone (AZ). By binding to Rab-interacting protein (RIM), bassoon and voltage-gated Ca²⁺channels (CaV), it is considered to be a central organizer of the topography of CaVand release sites of synaptic vesicles (SVs) at the AZ. Here, we investigated the role of RIM-BP2 at the endbulb of Held synapse of auditory nerve fibers with bushy cells of the cochlear nucleus, a fast relay of the auditory pathway with high release probability. Disruption of RIM-BP2 lowered release probability altering short-term plasticity and reduced evoked excitatory postsynaptic currents (EPSCs). Analysis of SV pool dynamics during high frequency train stimulation indicated a reduction of SVs with high release probability but an overall normal size of the readily releasable SV pool (RRP). The Ca2+-dependent fast component of SV replenishment after RRP depletion was slowed. Ultrastructural analysis by super-resolution light and electron microscopy revealed an impaired topography of presynaptic CaVand a reduction of docked and membrane-proximal SVs at the AZ. We conclude that RIM-BP2 organizes the topography of CaV, and promotes SV tethering and docking. This way RIM-BP2 is critical for establishing a high initial release probability as required to reliably signal sound onset information that we found to be degraded in bushy cells of RIM-BP2-deficient mice in vivo

    Volatiles in the Desert: Subtle Remote-sensing Signatures of the Dakhleh Oasis Catastrophic Event, Western Desert, Egypt

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    Over the past decade members of the Dakhleh Oasis Project have studied enigmatic signatures in the Pleistocene geologic record of portions of the Dakhleh oasis and palaeo-oasis in Egypt's Western Desert [1,2]. In particular, Si-Ca-Al rich glass melt (Dakhleh Glass, Fig. 1) points to a catastrophic event between c.100,000-200,000 years ago [3] in this well-studied African savannah and freshwater lake Middle Stone Age environment [4,5]

    Microservice Transition and its Granularity Problem: A Systematic Mapping Study

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    Microservices have gained wide recognition and acceptance in software industries as an emerging architectural style for autonomic, scalable, and more reliable computing. The transition to microservices has been highly motivated by the need for better alignment of technical design decisions with improving value potentials of architectures. Despite microservices' popularity, research still lacks disciplined understanding of transition and consensus on the principles and activities underlying "micro-ing" architectures. In this paper, we report on a systematic mapping study that consolidates various views, approaches and activities that commonly assist in the transition to microservices. The study aims to provide a better understanding of the transition; it also contributes a working definition of the transition and technical activities underlying it. We term the transition and technical activities leading to microservice architectures as microservitization. We then shed light on a fundamental problem of microservitization: microservice granularity and reasoning about its adaptation as first-class entities. This study reviews state-of-the-art and -practice related to reasoning about microservice granularity; it reviews modelling approaches, aspects considered, guidelines and processes used to reason about microservice granularity. This study identifies opportunities for future research and development related to reasoning about microservice granularity.Comment: 36 pages including references, 6 figures, and 3 table
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