180 research outputs found

    Walmart\u27s Sustainability Journey: Andy Ruben and the Design of Organizational Structures and Systems (B)

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    The case “Andy Ruben and the Design of Strategic Goals and Processes” flows from the previous discussion, by moving from the development of an ambitious vision to the challenges of adopting strategic policies and processes to reach those aspirations in practice. This case puts students into the role of Andy Ruben, Walmart’s first Vice-President for Sustainability , asking them to make concrete decisions about what should be done, in what order, and by what process if they were to implement an ambitious corporate sustainability strategy. In the case, Ruben confronts specific choices about how to define the responsibilities of the new sustainability office at Walmart in his efforts to lead the organization toward achieving Lee Scott’s vision. In Case B, we review the basic decisions Ruben made while building the resultant sustainability office

    Doppler Aliasing Reduction in Wide-Angle Synthetic Aperture Radar Using Phase Modulated Random Stepped-Frequency Waveforms

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    This research effort examines the theory, application and results of side-looking airborne radar operation in hot clutter. Hot clutter is an electronic counter-measure used to degrade the performance of airborne radar. Hot clutter occurs by illuminating the ground with an airborne jammer at some velocity, azimuth, elevation, and range from the airborne radar. When the received RCS scattered hot clutter waveform is perfectly coherent with the radar waveform, the radar believes the returns created by the hot clutter jammer resulted from the transmitting radar. Hot clutter degrades radar performance at locations in azimuth and Doppler. The effect of hot clutter is examined for side-looking airborne radar using adaptive and non-adaptive processing. Factored Time Space and Joint Domain Localized adaptive filters are shown to improve radar performance 32 to 36 dB per element per pulse, respectively, over non-adaptive processing in the mainbeam jammer normalized Doppler location when the jammer is not in the radar look direction in azimuth

    Walmart\u27s Sustainability Journey: Defining Sustainable Products (B)

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    In “Defining Sustainable Products (A),” we examine Walmart’s search for a systemic solution to define a sustainable product precisely. In this case, Matt Kistler, who succeeded Andy Ruben as the company sustainability leader in 2007, knows that the company is lagging behind on its espoused goal of selling sustainable products. The case asks students step into Kistler’s shoes as he leads Walmart’s sustainability office through a systematic review of the different models and frameworks available for measuring the sustainability of products presently in use. Eventually, the students face a decision about what Walmart should do to make systemic progress with regard to measuring and selling sustainable products. In “Defining Sustainable Products (B),” we examine the situation three years later, as Walmart assesses the progress made in achieving its goal of selling sustainable products

    Orion MPCV Continuum RCS Heating Augmentation Model Development

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    The reaction control system jets of the Orion Multi Purpose Crew Vehicle can have a significant impact on the magnitude and distribution of the surface heat flux on the leeside of the aft-body, when they are fired. Changes in surface heating are expressed in terms of augmentation factor over the baseline smooth body heating. Wind tunnel tests revealed heating augmentation factors as high as 13.0, 7.6, 2.8, and 5.8 for the roll, pitch down, pitch up, and yaw jets respectively. Heating augmentation factor models, based almost exclusively on data from a series of wind tunnel tests have been developed, for the purposes of thermal protection system design. The wind tunnel tests investigated several potential jet-to-freestream similarity parameters, and heating augmentation factors derived from the data showed correlation with the jet-to-freestream momentum ratio. However, this correlation was not utilized in the developed models. Instead augmentation factors were held constant throughout the potential trajectory space. This simplification was driven by the fact that ground to flight traceability and sting effects are not well understood. Given the sensitivity of the reaction control system jet heating augmentation to configuration, geometry, and orientation the focus in the present paper is on the methodology used to develop the models and the lessons learned from the data. The models that are outlined in the present work are specific to the aerothermal database used to design the thermal protection system for the Exploration Flight Test 1 vehicle

    After the war is over: the role of General Sir Arthur Currie in the development of academic medicine in Canada

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    Canadian universities faced a challenge with the return of a large cohort of battle-hardened students and faculty from the First World War. General Sir Arthur Currie, considered one of the few successful generals of the war, returned to a welcome of silence in Canada. McGill University exploited the opportunity to recruit him as its president. Currie oversaw a campaign of building construction and faculty development at McGill that also had a significant effect on the rest of Canada. Through his fostering of the Montreal Neurological Institute and the recruitment of Dr. Wilder Penfield, Currie facilitated the development of multidisciplinary medicine, which integrates clinical care with research — an aspiration still held by specialty medicine in Canada today

    Assessment of Turbulent CFD Against STS-128 Hypersonic Flight Data

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    Turbulent CFD simulations are compared against surface temperature measurements of the space shuttle orbiter windward tiles at reentry flight conditions. Algebraic turbulence models are used within both the LAURA and DPLR CFD codes. The flight data are from temperature measurements obtained by seven thermocouples during the STS-128 mission (September 2009). The flight data indicate boundary layer transition onset over the Mach number range 13.5{15.5, depending upon the location on the vehicle. But the boundary layer flow appeared to be transitional down through Mach 12, based upon the flight data and CFD trends. At Mach 9 the simulations match the flight data on average within 20 F/11 C, where typical surface temperatures were approximately 1600 F/870 C

    Structural transformations and disordering in zirconolite (CaZrTi2O7) at high pressure

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    There is interest in identifying novel materials for use in radioactive waste applications and studying their behavior under high pressure conditions. The mineral zirconolite (CaZrTi2O7) exists naturally in trace amounts in diamond-bearing deep-seated metamorphic/igneous environments, and it is also identified as a potential ceramic phase for radionuclide sequestration. However, it has been shown to undergo radiation-induced metamictization resulting in amorphous forms. In this study we probed the high pressure structural properties of this pyrochlore-like structure to study its phase transformations and possible amorphization behavior. Combined synchrotron X-ray diffraction and Raman spectroscopy studies reveal a series of high pressure phase transformations. Starting from the ambient pressure monoclinic structure, an intermediate phase with P21/m symmetry is produced above 15.6 GPa via a first order transformation resulting in a wide coexistence range. Upon compression to above 56 GPa a disordered metastable phase III with a cotunnite-related structure appears that is recoverable to ambient conditions. We examine the similarity between the zirconolite behavior and the structural evolution of analogous pyrochlore systems under pressure.<br/

    Exploration Flight Test 1 Afterbody Aerothermal Environment Reconstruction

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    The Exploration Flight Test 1 vehicle included roughly 100 near surface thermocouples on the after body of the vehicle. The temperature traces at each of these instruments have been used to perform inverse environment reconstruction to determine the aerothermal environment experienced during re-entry of the vehicle. This paper provides an overview of the reconstructed environments and identifies critical aspects of the environment. These critical aspects include transition and reaction control system jet influence. A blind test of the process and reconstruction tool was also performed to build confidence in the reconstructed environments. Finally, an uncertainty quantification analysis was also performed to identify the impact of each of the uncertainties on the reconstructed environments
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