1,388 research outputs found
Paper Session III-A - The Advanced Solid Rocket Motor Project
On April 21, 1989, NASA informed Lockheed CEO Dan Tellep that Lockheed Missiles & Space Company had been selected for negotiations of the Advanced Solid Rocket Motor (ASRM). Lockheed Missiles & Space Company, specifically the Missile Systems Division, is the prime contractor to the Marshall Space Flight Center for the ASRM. Teamed with Lockheed as major subcontractors are Aerojet Space Boosters and Rust International as shown in Figure 1. Lockheed Missiles Systems Division\u27s primary function for more than thirty years has been the systems management of major Fleet Ballistic Missile programs for the United States Navy. In those projects, Lockheed subcontractors have been all of the major solid propellant contractors in the United States. Lockheed\u27s role resulting from this experience base is that of project manager, where Lockheed provides systems engineering and integration of the entire project.
Lockheed\u27s association with Aerojet as subcontractor on the Polaris program, dates back to the mid-1950\u27s; thus the ASRM project represents a continuation of a long and productive association between the two major corporations. Aerojet, the major participant in the project, is responsible for the design, analysis and engineering of the rocket motor, as well as the manufacturing, quality assurance and testing. The other major subcontractor to Lockheed is Rust International, headquartered in Birmingham, Alabama. Rust is one of the largest domestic construction companies in the United States and will be responsible for the design and engineering of the facility, procurement and installation of equipment, and managing the construction activities
New Urbanism: From Exception to NormāThe Evolution of a Global Movement
This thematic issue explores the evolution of the New Urbanism, a normative planning and urban design movement that
has contributed to development throughout the world. Against a dominant narrative that frames the movement as a
straightforward application of principles that has yielded many versions of the same idea, this issue instead proposes an
examination of New Urbanism as heterogeneous in practice, shaped through multiple contingent factors that spell variegated translations of core principles. The contributing authors investigate how variegated forms of New Urbanism emerge,
interrogate why place-based contingencies lead to differentiation in practice, and explain why the movement continues to
be represented as a universal phenomenon despite such on-the-ground complexities. Together, the articles in this thematic
issue offer a powerful rebuttal to the idea that our understanding of the New Urbanism is somehow complete and provide
original ideas and frameworks with which to reassess the movementās complexity and understand its ongoing impact
Comparison of Family 9 Cellulases from Mesophilic and Thermophilic Bacteria
Cellulases containing a family 9 catalytic domain and a family 3c cellulose binding module (CBM3c) are important components of bacterial cellulolytic systems. We measured the temperature dependence of the activities of three homologs: Clostridium cellulolyticum Cel9G, Thermobifida fusca Cel9A, and C. thermocellum Cel9I. To directly compare their catalytic activities, we constructed six new versions of the enzymes in which the three GH9-CBM3c domains were fused to a dockerin both with and without a T. fusca fibronectin type 3 homology module (Fn3). We studied the activities of these enzymes on crystalline cellulose alone and in complex with a miniscaffoldin containing a cohesin and a CBM3a. The presence of Fn3 had no measurable effect on thermostability or cellulase activity. The GH9-CBM3c domains of Cel9A and Cel9I, however, were more active than the wild type when fused to a dockerin complexed to scaffoldin. The three cellulases in complex have similar activities on crystalline cellulose up to 60Ā°C, but C. thermocellum Cel9I, the most thermostable of the three, remains highly active up to 80Ā°C, where its activity is 1.9 times higher than at 60Ā°C. We also compared the temperature-dependent activities of different versions of Cel9I (wild type or in complex with a miniscaffoldin) and found that the thermostable CBM is necessary for activity on crystalline cellulose at high temperatures. These results illustrate the significant benefits of working with thermostable enzymes at high temperatures, as well as the importance of retaining the stability of all modules involved in cellulose degradation
Mott Transition, Compressibility Divergence and P-T Phase Diagram of Layered Organic Superconductors: An Ultrasonic Investigation
The phase diagram of the organic superconductor
-(BEDT-TTF)Cu[N(CN)Cl has been investigated by ultrasonic
velocity measurements under helium gas pressure. Different phase transitions
were identified trough several elastic anomalies characterized from isobaric
and isothermal sweeps. Our data reveal two crossover lines that end on the
critical point terminating the first-order Mott transition line. When the
critical point is approached along these lines, we observe a dramatic softening
of the velocity which is consistent with a diverging compressibility of the
electronic degrees of freedom.Comment: 4 pages, 5 figure
Are Split Tablet Keyboards Better? A Study of Soft Keyboard Layout and Hand Posture
acceptedVersio
A 7-year follow-up of sacral anterior root stimulation for bladder control in patients with a spinal cord injury: quality of life and users' experiences\ud
Study design: Cross-sectional descriptive study.\ud
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Objectives: To assess long-term effects and quality of life (QoL) of using sacral anterior root stimulation (SARS) in spinal cord injured patients.\ud
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Setting: Neurosurgical and Urological Departments of a large teaching hospital and a large rehabilitation centre in the Netherlands.\ud
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Methods: In all, 42 patients with complete spinal cord injury (SCI) implanted between 1987 and 2000 were included. A questionnaire was constructed to determine complications, technical failures and personal experiences of the patients. The Qualiveen questionnaire was used and the outcome was compared with data obtained from a reference group of 400 SCI patients with neurogenic bladder problems not using the bladder controller. The Qualiveen questionnaire measures disease-specific aspects in four domains with respect to limitations, constraints, fears and feelings and general QoL aspects, suitable for use in SCI patients with urinary disorders.\ud
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Results: The results of 37 patients are presented. Our results with the bladder controller with respect to medical and technical complications and infection rates are similar to the results presented by others. From users' experiences, the most important advantages reported were a decreased infection rate (68%), improved social life (54%) and continence (54%). Comparison of the obtained results of our patient group with the Qualiveen questionnaire with a reference group not using the bladder controller indicates that the specific impact of urinary disorders in the four domains on QoL is reduced and that general QoL is improved.\ud
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Conclusion: SARS is effective and safe for neurogenic bladder management in patients with complete SCI. Users' experiences are positive. Furthermore, this therapy seems to reduce the effects of urinary-disorder-specific QoL aspects, and to increase the QoL in general\u
Template for Developing Guidelines for the Evaluation of the Clinical Efficacy of Psychophysiological Interventions
An essential function of both the Association for Applied Psychophysiology and Biofeedback (AAPB) and the Society for Neuronal Regulation (SNR) is the systematic evaluation of psychophysiological interventions that have been developed for the treatment of medical and psychiatric disorders. In order to address scientific concerns regarding the efficacy of specific clinical applications of biofeedback, these two societies formed and Efficacy Task Force. The process to be used in the assessment of treatment efficacy, specificity and clinical utility is presented in the form of a template that will serve as the foundation for a series of scientific reviews and practice guidlines to be published by both societies
On high-temperature evolution of passivation layer in Liā10 wt % Mg alloy via in situ SEM-EBSD
Liā10 wt % Mg alloy (Liā10 Mg) is used as an anode material for a solid-state battery with excellent electrochemical performance and no evidence of dendrite formation during cycling. Thermal treatment of Li metal during manufacturing improves the interfacial contact between a Li metal electrode and solid electrolyte to achieve an all solid-state battery with increased performance. To understand the properties of the alloy passivation layer, this paper presents the first direct observation of its evolution at elevated temperatures (up to 325Ā°C) by in situ scanning electron microscopy. We found that the morphology of the surface passivation layer was unchanged above the alloy melting point, while the bulk of the material below the surface was melted at the expected melting point, as confirmed by in situ electron backscatter diffraction. In situ heat treatment of Li-based materials could be a key method to improve battery performance
Phenomenological model for the remanent magnetization of dilute quasi-one-dimensional antiferromagnets
We present a phenomenological model for the remanent magnetization at low
temperatures in the quasi-one-dimensional dilute antiferromagnets
CH_{3}NH_{3}Mn_{1-x}Cd_{x} Cl_{3}\cdot 2H_{2}O and
(CH_{3})_{2}NH_{2}Mn_{1-x}Cd_{x}Cl_{3}\cdot 2H_{2}O. The model assumes the
existence of uncompensated magnetic moments induced in the odd-sized segments
generated along the Mn(^{2+}) chains upon dilution. These moments are further
assumed to correlate ferromagnetically after removal of a cooling field. Using
a (mean-field) linear-chain approximation and reasonable set of model
parameters, we are able to reproduce the approximate linear temperature
dependence observed for the remanent magnetization in the real compounds.Comment: 5 pages, 2 figures; final version to appear in Physical Review
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Summary of hydrogeologic controls on ground-water flow at the Nevada Test Site, Nye County, Nevada
The underground testing of nuclear devices has generated substantial volumes of radioactive and other chemical contaminants below ground at the Nevada Test Site (NTS). Many of the more radioactive contaminants are highly toxic and are known to persist in the environment for thousands of years. In response to concerns about potential health hazards, the US Department of Energy, under its Environmental Restoration Program, has made NTS the subject of a long-term investigation. Efforts will assess whether byproducts of underground testing pose a potential hazard to the health and safety of the public and, if necessary, will evaluate and implement steps to remediate any of the identified dangers. Ground-water flow is the primary mechanism by which contaminants can be transported significant distances away from the initial point of injection. Flow paths between contaminant sources and potential receptors are separated by remote areas that span tens of miles. The diversity and structural complexity of the rocks along these flow paths complicates the hydrology of the region. Although the hydrology has been studied in some detail, much still remains uncertain about flow rates and directions through the fractured-rock aquifers that transmit water great distances across this arid region. Unique to the hydrology of NTS are the effects of underground testing, which severely alter local rock characteristics and affect hydrologic conditions throughout the region. This report summarizes what is known and inferred about ground-water flow throughout the NTS region. The report identifies and updates what is known about some of the major controls on ground-water flow, highlights some of the uncertainties in the current understanding, and prioritizes some of the technical needs as related to the Environmental Restoration Program. 113 refs
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