Prosthetic device for correction of urinary incontinence

The development and current status of a prosthetic device for the correction of urinary incontinence is presented

History, design and performance of the space shuttle hazardous gas detection system

The Hazardous Gas Detection System (HGDS) is designed to detect leaks hich could result in pre-launch or in-flight fires or explosions resulting from the presence of cryogenic rocket propellants. The historical development, design, and performance of the HGDS is discussed. Data for response time, detection limits, accuracy, and drift are presented. Finally, present and future applications are discussed, and some general conclusions are drawn

A portable hypergolic oxidizer vapor sensor for NASA's Space Shuttle program

The design and performance characteristics of an electrochemical NO2 sensor selected by NASA for the space shuttle program is described. The instrument consists of a sample pump, an electrochemical cell, and control and display electronics. The pump pushes the sample through the electrochemical cell where the vapors are analyzed and an output proportional to the NO2 concentration is produced. The output is displayed on a panel meter, and is also available at a recorder jack. The electrochemical cell is made up of a polypropylene chamber covered with teflon membrane faceplates. Plantinum electrodes are bonded to the faceplates, and the sensing and counter electrodes are potentiostatically controlled at -200 mV with respect to the reference electrode. The cell is filled with electrolyte, consisting of 13.5 cc of 23% solution of KOH

Prosthetic urinary sphincter

A pump/valve unit for controlling the inflation and deflation of a urethral collar in a prosthetic urinary sphincter device is described. A compressible bulb pump defining a reservoir was integrated with a valve unit for implantation. The valve unit includes a movable valve member operable by depression of a flexible portion of the valve unit housing for controlling fluid flow between the reservoir and collar; and a pressure sensing means which operates the valve member to relieve an excess pressure in the collar should too much pressure be applied by the patient

Advanced Gas Turbine (AGT) powertrain system

A 74.5 kW(100 hp) advanced automotive gas turbine engine is described. A design iteration to improve the weight and production cost associated with the original concept is discussed. Major rig tests included 15 hours of compressor testing to 80% design speed and the results are presented. Approximately 150 hours of cold flow testing showed duct loss to be less than the design goal. Combustor test results are presented for initial checkout tests. Turbine design and rig fabrication is discussed. From a materials study of six methods to fabricate rotors, two have been selected for further effort. A discussion of all six methods is given

Advanced Gas Turbine (AGT) power-train system development

Technical work on the design and component testing of a 74.5 kW (100 hp) advanced automotive gas turbine is described. Selected component ceramic component design, and procurement were tested. Compressor tests of a modified rotor showed high speed performance improvement over previous rotor designs; efficiency improved by 2.5%, corrected flow by 4.6%, and pressure ratio by 11.6% at 100% speed. The aerodynamic design is completed for both the gasifier and power turbines. Ceramic (silicon carbide) gasifier rotors were spin tested to failure. Improving strengths is indicated by burst speeds and the group of five rotors failed at speeds between 104% and 116% of engine rated speed. The emission results from combustor testing showed NOx levels to be nearly one order of magnitude lower than with previous designs. A one piece ceramic exhaust duct/regenerator seal platform is designed with acceptable low stress levels

Holding the Line in I Corps: The Unintended Consequences of McNamara\u27s Electronic Fence

The primary focus of this thesis is the development, implementation, and results of a multi-billion dollar electronic anti-personnel barrier that once divided North and South Vietnam during America\u27s involvement in the Vietnam War, a conflict that pitted the strongest nation on earth against one of the weakest. United States participation in the Vietnam War lasted from 1959 to 1975 in one degree or another and conservatively cost the world more than two million lives, among them almost 57,000 Americans, two million Vietnamese, 1.5 million Cambodians, several hundred thousand Laotians, and a smaller number of Thais, Filipinos, Australians, New Zealanders, Chinese, and Russians. The American military was ostensibly brought into the conflict to prevent the Communist takeover of nominally democratic South Vietnam by Communist North Vietnam. The effort failed. The North Vietnamese victors, who call America\u27s involvement in Vietnam the American War, argue America\u27s parsimonious withdrawal from Vietnam was the final days of a 2,000-year struggle to obtain independence from the generations of invaders who have occupied their land. During the war the United States introduced literally hundreds of new weapons systems, perfected the concept of combined arms and the integrated battlefield, and solicited the best scientific minds in America to devise ways of defeating the North Vietnamese. Finally it deployed its most devastating weapons short of nuclear warheads, and still lost the war. America \u27s defeat in Vietnam set the stage for dozens of wars for independence and wars for unification all lumped together as regional conflicts. Currently so-called Third World revolutionaries and separatists are taking up arms against both the mighty democracies and proxies and member states of the former Soviet Union using revolutionary models introduced by the North Vietnamese and its proxies to defeat America. And almost thirty-five years after the last shots were fired in Vietnam ideological and philosophical arguments still rage over the validity of America\u27s involvement in that war. The victor was a backward looking Communist dictatorship equally at home using weapons as primitive as sharpened sticks contaminated with human dung and as modern as the best anti-aircraft missile defenses the Soviet Union and Communist China could produce. Instead of fighting America\u27s might on its terms, the army of North Vietnam tunneled into the ground and melted away only to reappear when it was to its advantage. Frustrated with such simple tactics and unable to cope with the lack of political will manifested by the powerful anti-war movement at home, America eventually lost will to fight. Once that occurred North Vietnamese prevailed over the mightiest military force ever assembled on earth. The second purpose of this research paper is to demonstrate to the reader the writer\u27s ability to implement currently available digital publishing concepts an

Contributions of Seed Bank and Vegetative Propagules to Vegetation Composition on Prairie Dog Colonies in Western South Dakota

Characterizing the contributions of the seed bank and vegetative propagules will enhance our understanding of community resiliency associated with prairie dog disturbances. Our objective was to determine the effects of ecological condition (EC) and distance from burrows on the soil seed bank and vegetative propagules. Based on species composition of the extant vegetation, two prairie dog colonies were selected on the Buffalo Gap National Grasslands in western South Dakota. Within each colony, two prairie dog burrows were randomly selected at each of three sample points located about 150m apart. Two soil cores were taken at 0.5m, 1.0m, and 1.5m distances from the center of each burrow. Cores used to evaluate the seed bank were sifted and spread within standard seed flats, while cores used to determine vegetative propagules were placed intact into plastic pots. Both were maintained in a greenhouse for daily monitoring. A total 450 seedlings representing 16 species emerged from the low EC seed flats while 550 seedlings comprising 24 species emerged from the high EC seed flats. Sixty-two percent of the low EC and 67% of the high EC species emerged from the seed flats were annuals. On the low EC colony, 43 shoots generated from vegetative propagules representing 7 species, two of which were also found in the seed flats. On the high EC colony, 431 shoots sprouted from vegetative propagules representing 5 species, 3 of which were not present in the seed flats. Fourteen percent of the low EC and 80% of the high EC species emerged as vegetative propagules were perennial native grasses. Distance from burrows had no impact on species richness within each EC. Both colonies demonstrated considerable revegetation potential but differed with respect to relative contributions from the soil seed bank and vegetative propagules

Closed-loop recycling of plastics enabled by dynamic covalent diketoenamine bonds.

Recycled plastics are low-value commodities due to residual impurities and the degradation of polymer properties with each cycle of re-use. Plastics that undergo reversible polymerization allow high-value monomers to be recovered and re-manufactured into pristine materials, which should incentivize recycling in closed-loop life cycles. However, monomer recovery is often costly, incompatible with complex mixtures and energy-intensive. Here, we show that next-generation plastics-polymerized using dynamic covalent diketoenamine bonds-allow the recovery of monomers from common additives, even in mixed waste streams. Poly(diketoenamine)s 'click' together from a wide variety of triketones and aromatic or aliphatic amines, yielding only water as a by-product. Recovered monomers can be re-manufactured into the same polymer formulation, without loss of performance, as well as other polymer formulations with differentiated properties. The ease with which poly(diketoenamine)s can be manufactured, used, recycled and re-used-without losing value-points to new directions in designing sustainable polymers with minimal environmental impact

Application of knowledge network analysis to identify knowledge sharing bottlenecks at an engineering firm

The knowledge of an organization’s employees is a valuable asset. Therefore organizations should ensure that their employees share their knowledge among each other. Knowledge exchanges between employees can be modelled as a network of relationships. To study these networks we have developed the Knowledge Network Analysis technique, which is based on Social Network Analysis and supports visual as well as quantitative analysis of knowledge networks. The goal of this technique is to identify bottlenecks in knowledge sharing in a particular knowledge area. In this paper we present the results of the application of Knowledge Network Analysis in an explorative case study. The goal of the case study is to explore the usefulness of Knowledge Network Analysis in identifying knowledge sharing bottlenecks. The case study results in a deeper understanding of how to translate the characteristics of the knowledge network and the employees in this network to the context of the case study organization. Moreover, the case study results have also been used to formulate recommendations to improve knowledge sharing at the case study organization