13,254 research outputs found

    Results of Millikan Library Forced Vibration Testing

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    This report documents an investigation into the dynamic properties of Millikan Library under forced excitation. On July 10, 2002, we performed frequency sweeps from 1 Hz to 9.7 Hz in both the East-West (E-W) and North-South (N-S) directions using a roof level vibration generator. Natural frequencies were identified at 1.14 Hz (E-W fundamental mode), 1.67 Hz (N-S fundamental mode), 2.38 Hz (Torsional fundamental mode), 4.93 Hz (1st E-Wovertone), 6.57 Hz (1st Torsional overtone), 7.22 Hz (1st N-S overtone), and at 7.83 Hz (2nd E-Wovertone). The damping was estimated at 2.28% for the fundamental E-W mode and 2.39% for the N-S fundamental mode. On August 28, 2002, a modal analysis of each natural frequency was performed using the dense instrumentation network located in the building. For both the E-W and N-S fundamental modes, we observe a nearly linear increase in displacement with height, except at the ground floor which appears to act as a hinge. We observed little basement movement for the E-W mode, while in the N-S mode 30% of the roof displacement was due to basement rocking and translation. Both the E-W and N-S fundamental modes are best modeled by the first mode of a theoretical bending beam. The higher modes are more complex and not well represented by a simple structural system

    Development of an adaptive window-opening algorithm to predict the thermal comfort, energy use and overheating in buildings

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    This investigation of the window opening data from extensive field surveys in UK office buildings demonstrates: 1) how people control the indoor environment by opening windows; 2) the cooling potential of opening windows; and 3) the use of an ‘adaptive algorithm’ for predicting window opening behaviour for thermal simulation in ESP-r. It was found that when the window was open the mean indoor and outdoor temperatures were higher than when closed, but show that nonetheless there was a useful cooling effect from opening a window. The adaptive algorithm for window opening behaviour was then used in thermal simulation studies for some typical office designs. The thermal simulation results were in general agreement with the findings of the field surveys. The adaptive algorithm is shown to provide insights not available using non adaptive simulation methods and can assist in achieving more comfortable, lower energy buildings while avoiding overheating

    Comfort driven adaptive window opening behaviour and the influence of building design

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    It is important to understand and model the behaviour of occupants in buildings and how this behaviour impacts energy use and comfort. It is similarly important to understand how a buildings design affects occupant comfort, occupant behaviour and ultimately the energy used in the operation of the building. In this work a behavioural algorithm for window opening developed from field survey data has been implemented in a dynamic simulation tool. The algorithm is in alignment with the proposed CEN standard for adaptive thermal comfort. The algorithm is first compared to the field study data then used to illustrate the impact of adaptive behaviour on summer indoor temperatures and heating energy. The simulation model is also used to illustrate the sensitivity of the occupant adaptive behaviour to building design parameters such as solar shading and thermal mass and the resulting impact on energy use and comfort. The results are compared to those from other approaches to model window opening behaviour. The adaptive algorithm is shown to provide insights not available using non adaptive simulation methods and can assist in achieving more comfortable and lower energy buildings

    Beam alignment techniques based on the current multiplication effect in photoconductors Third summary technical progress report, 15 Nov. 1966 - 15 Oct. 1967

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    Beam alignment techniques developed for infrared sensitive single crystal germanium to study multiplication effect in photoconductor

    Ecophysiological traits of grasses: resolving the effects of photosynthetic pathway and phylogeny

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    C4 photosynthesis is an important example of convergent evolution in plants, having arisen in eudicots, monocots and diatoms. Comparisons between such diverse groups are confounded by phylogenetic and ecological differences, so that only broad generalisations can be made about the role of C4 photosynthesis in
determining ecophysiological traits. However, 60% of C4 species occur in the grasses (Poaceae) and molecular phylogenetic techniques confirm that there are between 8 and 17 independent origins of C4 photosynthesis in the Poaceae. In a screening experiment, we compared leaf physiology and growth traits across several major
independent C3 & C4 groups within the Poaceae, asking 1) which traits differ consistently between photosynthetic
types and 2) which traits differ consistently between clades within each photosynthetic type

    All Pain, Whose Gain? A Fifty-State Analysis of the Independent State Legislature Doctrine for Redistricting

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    The “Independent State Legislature” (ISL) doctrine has recently been offered as a reinterpretation of legislative control over federal elections and may upend decades of election law precedent. Based on Article I of the U.S. Constitution, the ISL doctrine holds that such authority of state legislatures potentially overrides state constitutions, as well as state courts, citizen initiatives, and even the governor. The original political goals of the ISL doctrine were the 2000 and 2016 Presidential elections. The doctrine has recently come before the Supreme Court in Moore v. Harper, a case concerning redistricting, and could open the door to increased gerrymandering of U.S. congressional districts. Here we analyze the practical consequences in all fifty states. We find that such a change in redistricting law would be highly asymmetric to the major political parties, giving considerable advantage to Democrats because it would undo an existing propensity for reform or judicial intervention in Democratic-leaning and swing states. This asymmetry raises questions of the desirability of introducing the ISL to questions of redistricting
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