255 research outputs found

    Expendable oceanographic mooring (XMOOR)

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    An expendable, self-deploying mooring (XMOOR) for shallow water applications has been developed to address Navy requirements for environmental monitoring. The project has been conducted jointly between the Woods Hole Oceanographic Institution and the Naval Research Laboratory at Stennis, MS. WHOI has taken the lead on the mechanical design of the system while NR has developed the electronics. Eight prototype XMOOR systems have been built. They are designed for water depths between 10 and 100m, for deployments of up to 3-months duration, and for automatic deployment. Their sensor suite includes barometrc pressure, air temperatue, water temperature at up to 25 levels, and conductivity and pressure at up to 3 levels. Data telemetry is accomplished via the Argos DCS and by line-of-sight VH confguration of the data collection program. This report describes the XMOOR mechanical system. The data collection and telemetry systems are described separately in (1) and (2).Funding was provided by the Office of Naval Research through Contract Nos. NOOO-14-92-C-6028 and NOOO-14-95-1-0774

    1988 Convocation

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    Opening Selections: First Class Brass, George Frederich Handel Processional: Jean Joseph Mouret Welcome: Dr. Leon Lederman, Director, Fermi Laboratory, Vice President Board of Trustees; Dr. Stephanie Pace Marshall, Director; David Kung, Student Council President Introductions: Dr. Stephanie Pace Marshall, Director Musical Selection: Franz Von Suppe Keynote Speaker: Dr. Donald Frye, Former Chief Executive Bell & Howell Co., Professor of Industrial Engineering and Management Science, Northwestern University Recessional: George Frederich Hande

    The Relationship of Expert-System Scored Constrained Free-Response Items to Multiple-Choice and Open-Ended Items

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    This study examined the relationship of an expert- system scored constrained free-response item (requir ing the student to debug a faulty computer program) to two other item types: (1) multiple-choice and (2) free- response (requiring production of a program). Confir matory factor analysis was used to test the fit of a three-factor model to these data and to compare the fit of the model to three alternatives. These models were fit using two random-half samples, one given a faulty program containing one bug and the other a program with three bugs. A single-factor model best fit the data for the sample taking the one-bug constrained free re sponse and a two-factor model fit the data somewhat better for the second sample. In addition, the factor intercorrelations showed this item type to be highly re lated to both the free-response and multiple-choice measures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68260/2/10.1177_014662169001400204.pd

    MApping the Most Massive Overdensities Through Hydrogen (MAMMOTH) I: Methodology

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    Modern cosmology predicts that a galaxy overdensity is associated to a large reservoir of the intergalactic gas, which can be traced by the Lyα\alpha forest absorption. We have undertaken a systematic study of the relation between Coherently Strong intergalactic Lyα\alpha Absorption systems (CoSLAs), which have highest optical depth (τ\tau) in τ\tau distribution, and mass overdensities on the scales of \sim 10 - 20 h1h^{-1} comoving Mpc. On such large scales, our cosmological simulations show a strong correlation between the effective optical depth (τeff\tau_{\rm{eff}}) of the CoSLAs and the 3-D mass overdensities. In moderate signal-to-noise spectra, however, the profiles of CoSLAs can be confused with high column density absorbers. For z>2.6z>2.6, where the corresponding Lyβ\beta is redshifted to the optical, we have developed the technique to differentiate between these two alternatives. We have applied this technique to SDSS-III quasar survey at z=2.6z = 2.6 - 3.3, and we present a sample of five CoSLA candidates with τeff\tau_{\rm{eff}} on 15 h1h^{-1} Mpc greater than 4.5×4.5\times the mean optical depth. At lower redshifts of z<2.6z < 2.6, where the background quasar density is higher, the overdensity can be traced by intergalactic absorption groups using multiple sight lines. Our overdensity searches fully utilize the current and next generation of Lyα\alpha forest surveys which cover a survey volume of >(1 h1> (1\ h^{-1} Gpc)3^3. In addition, systems traced by CoSLAs will build a uniform sample of the most massive overdensities at z>2z > 2 to constrain the models of structure formation, and offer a unique laboratory to study the interactions between galaxy overdensities and the intergalactic medium.Comment: 24 pages, 30 figures, 8 tables, submitted to the Astrophysical Journa

    The Effect of High Efficiency Building Technologies and PV Generation on the Energy Profiles for Typical US Residences

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    The penetrations of high efficiency technologies and photovoltaic (PV) generation are increasing in the residential sector. Technologies such as improved insulation and efficient HVAC systems significantly affect the energy profile of a house. This effect varies due to climate characteristics, i.e. temperature, solar radiation, relative humidity, and wind speeds. The effect of other technologies, such as efficient water heaters, lighting, or kitchen appliances, is mainly governed by human behavior, which may be represented by a schedule. This paper studies the performance of both climate-influenced and scheduled household devices among different levels of efficiency through combined computational and experimental methods. Three houses were constructed by the Tennessee Valley Authority and were outfitted with robots that mimicked the occupation of a family. The houses represented three categories of residences, namely, typical builder, retrofit, and near net-zero-energy. With the energy and weather data collected from 2009 to 2014, a total of four house energy models were developed to account for equipment changes throughout the years. The studies performed using these models considered the behavior of the HVAC systems, PV system, and water heaters as well as climate effects

    Virtual Power Plant Control for Large Residential Communities Using HVAC Systems for Energy Storage

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    Heating, ventilation, and air-conditioning (HVAC) systems use the most electricity of any household appliance in residential communities. HVAC system modeling facilitates the study of demand response (DR) at both the residential and power system levels. In this article, the equivalent thermal model of a reference house is proposed. Parameters for the reference house were determined based on the systematic study of experimental data obtained from fully instrumented field demonstrators. Energy storage capacity of HVAC systems is calculated and an equivalent state-of-charge is defined. The uniformity between HVAC systems and battery energy storage system is demonstrated by DR control. The aggregated HVAC load model is based on the reference house and considers a realistic distribution of HVAC parameters derived from one of the largest smart grid field demonstrators in rural America. A sequential DR scheme as part of a virtual power plant control is proposed to reduce both ramping rate and peak power at the aggregated level, while maintaining human comfort according to ASHRAE standards

    Demand Response of HVACs in Large Residential Communities Based on Experimental Developments

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    Heating, ventilation, and air-conditioning (HVAC) systems contribute the largest electricity usage for a residential community. Modeling of the HVAC systems facilitate the study of demand response (DR) at both the residential and the power system level. In this paper, the equivalent thermal model of a reference house was proposed. Parameters for the reference house were determined based on the systematic study of experimental data obtained from fully instrumented field demonstrators. The aggregated HVAC load was modeled based on the reference house while considering a realistic distribution of HVAC parameters derived from data that was provided by one of the largest smart grid field demonstrators in rural America. A sequential DR as part of a Virtual Power Plant (VPP) control was proposed to reduce both ramping rate and peak power at the aggregated level, while maintaining human comfort according to ASHRAE standard
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