Index to NASA Tech Briefs, 1972

Abstracts of 1972 NASA Tech Briefs are presented. Four indexes are included: subject, personal author, originating center, and Tech Brief number

Aeronautical Engineering: A special bibliography with indexes, supplement 48

This special bibliography lists 291 reports, articles, and other documents introduced into the NASA scientific and technical information system in August 1974

Genetic Analysis and Cell Manipulation on Microfluidic Surfaces

Personalized cancer medicine is a cancer care paradigm in which diagnostic and therapeutic strategies are customized for individual patients. Microsystems that are created by Micro-Electro-Mechanical Systems (MEMS) technology and integrate various diagnostic and therapeutic methods on a single chip hold great potential to enable personalized cancer medicine. Toward ultimate realization of such microsystems, this thesis focuses on developing critical functional building blocks that perform genetic variation identification (single-nucleotide polymorphism (SNP) genotyping) and specific, efficient and flexible cell manipulation on microfluidic surfaces. For the identification of genetic variations, we first present a bead-based approach to detect single-base mutations by performing single-base extension (SBE) of SNP specific primers on solid surfaces. Successful genotyping of the SNP on exon 1 of HBB gene demonstrates the potential of the device for simple, rapid, and accurate detection of SNPs. In addition, a multi-step solution-based approach, which integrates SBE with mass-tagged dideoxynucleotides and solid-phase purification of extension products, is also presented. Rapid, accurate and simultaneous detection of 4 loci on a synthetic template demonstrates the capability of multiplex genotyping with reduced consumption of samples and reagents. For cell manipulation, we first present a microfluidic device for cell purification with surface-immobilized aptamers, exploiting the strong temperature dependence of the affinity binding between aptamers and cells. Further, we demonstrate the feasibility of using aptamers to specifically separate target cells from a heterogeneous solution and employing environmental changes to retrieve purified cells. Moreover, spatially specific capture and selective temperature-mediated release of cells on design-specified areas is presented, which demonstrates the ability to establish cell arrays on pre-defined regions and to collect only specifically selected cell groups for downstream analysis. We also investigate tunable microfluidic trapping of cells by exploiting the large compliance of elastomers to create an array of cell-trapping microstructures, whose dimensions can be mechanically modulated by inducing uniform strain via the application of external force. Cell trapping under different strain modulations has been studied, and capture of a predetermined number of cells, from single cells to multiple cells, has been achieved. In addition, to address the lack of aptamers for targets of interest, which is a major hindrance to aptamer-based cell manipulation, we present a microfluidic device for synthetically isolating cell-targeting aptamers from a randomized single-strand DNA (ssDNA) library, integrating cell culturing with affinity selection and amplification of cell-binding ssDNA. Multi-round aptamer isolation on a single chip has also been realized by using pressure-driven flow. Finally, some perspectives on future work are presented, and strategies and notable issues are discussed for further development of MEMS/microfluidics-based devices for personalized cancer medicine

Aeronautical Engineering: A continuing bibliography with indexes, supplement 106

This bibliography lists 388 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1979

Development and Launch of the World\u27s First Orbital Propellant Tanker

This paper describes the development of Orbit Fab’s Tanker-001 Tenzing mission, the world’s first orbital propellant tanker. The development of a robust orbital propellant supply chain is critical to accelerating the growth of government and commercial space activities. The widespread availability of spacecraft refueling has the potential to provide a number of revolutionary benefits. High-value space assets could have their operational lives extended, as they would no longer be constrained by the amount of propellant stored onboard for maneuvering. On-orbit servicing missions would become more efficient, as servicing vehicles could be refueled and repeatedly used. A large orbital propellant supply would also enable new mission and business models based on operational flexibility and frequent maneuvering. These benefits would be particularly impactful on small satellites, where the ability to refuel could overcome the operational constraints of having smaller propellant tanks. This will greatly expand the market for small spacecraft as it increases their range of missions and capabilities. Launching no earlier than June 24, 2021, Tenzing is a 35 kg small satellite with an Astro Digital bus carrying a supply of storable propellant, high test peroxide (HTP). Tenzing’s propellant supply is being offered to customers for refueling and used to gather data on propellant storage. In addition to being the first propellant tanker, Tenzing is also an orbital laboratory including a variety of payloads intended to test key technologies for refueling. This includes the first flight of Orbit Fab’s Rapidly Attachable Fluid Transfer Interface (RAFTI), a stereo camera system, and a Halcyon HTP propulsion system designed and built by Benchmark Space Systems for orbital maneuvers. The latter two elements can be used to test rendezvous and flyby maneuvers, providing data to support the development of full rendezvous, proximity operations, and docking (RPOD) systems for future Orbit Fab missions

NASA Tech Briefs Index, 1977, volume 2, numbers 1-4

Announcements of new technology derived from the research and development activities of NASA are presented. Abstracts, and indexes for subject, personal author, originating center, and Tech Brief number are presented for 1977

Advanced Diagnostic Techniques Applied to Polymer Electrolyte Fuel Cells

Polymer electrolyte fuel cells (PEFCs) are among the most promising energy conversion technologies for a broad range of applications, offering zero-emission electricity generation by converting hydrogen directly into electrical energy at high efficiencies. Tremendous advancements have been made in terms of performance and durability but technological challenges still exist which hinder their widespread adoption; these challenges range from material durability to system design and operating strategies. Developing this technology requires a comprehensive understanding of its fundamental operation, coupled with effective diagnostic techniques. Performance, temperature and hydration in a PEFC is a complex relationship governed by cause-and-effect, where a change in one factor alters the other. These problems are exacerbated during scale-up, advancing from small lab-scale single cells to large commercial automotive stacks, where operational heterogeneities encourage large current and temperature variations, resulting in varied local degradation rates and inefficient PEFC performance. This study characterises these parameters in-operando by adopting diagnostic techniques such as current, temperature and pressure mapping, coupled with electrochemical techniques, to garner a broader understanding of the formation of these heterogeneities. The development of new diagnostic techniques for both research and industry is also crucial for the commercialisation of PEFCs, as stack-level diagnostic resources are limited. These are required to be straightforward in application and interpretation, cost-effective and with short testing times. Novel diagnostic techniques are presented in this study which aim to bridge this gap in the diagnostic sector. Lock-in thermography is used to image sub-surface water content during cell operation using a thermal imaging camera, producing water distribution images at various penetration depths. A complementary transfer function technique is also developed, termed heat-stimulus thermo-electric impedance spectroscopy (HS-TEIS), which considers the complex relationship between imposed temperature change and electrical response as a function of frequency

Modern Data Acquisition, System Design, and Analysis Techniques and their Impact on the Physics-based Understanding of Neutron Coincidence Counters used for International Safeguards (draft)

Neutron coincidence counting is a technique widely used in the field of international safeguards for the mass quantification of a fissioning item. It can exploit either passive or active interrogation techniques to assay a wide range of plutonium, uranium, and mixed oxide items present in nuclear facilities worldwide. Because neutrons are highly penetrating, and the time correlation between events provides an identifiable signature, when combined with gamma spectroscopy, it has been used for nondestructive assays of special nuclear material for decades. When neutron coincidence counting was first established, a few system designs emerged as standards for assaying common containers. Over successive decades, new systems were developed for a wider variety of inspection assays. Simultaneously, new system characterization procedures, data acquisition technologies, and performance optimizations were made. The International Atomic Energy Agency has been using many of these original counters for decades, despite the large technological growth in recent years. This is both a testament and an opportunity. This dissertation explores several topics in which the performance of neutron coincidence counting systems is studied such that their behavior may be better understood from physical models, and their applications may be expanded to a greater field of interest. Using modern list mode data acquisition and analysis, procedures are developed, implemented, and exploited to expand the information obtained of both these systems and sources in question in a common measurement. System parameters such as coincidence time windows, dead time, efficiency, die-away time, and non-ideal double pulsing are explored in new ways that are not possible using traditional shift register logic. In addition, modern amplifier electronics are retrofitted in one model, the Uranium Neutron Coincidence Collar, to allow for a count rate-based source spatial response matrix to be measured, ultimately for the identification of diversion in a fresh fuel assembly. The testing, evaluation, and optimization of these electronics is described; they may serve as a more capable alternative to existing electronics used in IAEA systems. Finally, with a thorough understanding of the system characteristics and performance, neutron coincidence counters may be used to self-certify calibration sources with superior precision to national metrological laboratories

Institute of Safety Research, Annual Report 1995

The report gives an overview on the scientific work of the Institute of Safety Research in 1995