ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Inorganic Chemistry  (83,671)
  • LUNAR AND PLANETARY EXPLORATION  (14,409)
  • Mechanical Engineering
  • Temperatur
Collection
Keywords
Language
Years
  • 1
    Publication Date: 2024-04-11
    Description: Experiments to characterize the effects of moisture content and temperature on the mechanical properties of concrete were conducted. Based on these experiments, a new overall material model capable of predicting the mechanical behaviour of concrete subject to elevated temperatures up to 100 °C was developed. The material model estimates the time, temperature and moisture dependency of the compressive and tensile strength, creep and shrinkage of concrete.
    Keywords: TA1-2040 ; concrete ; Temperatur ; Beton ; Schwinden ; Temperature ; strength ; Kriechen ; creep ; Festigkeit ; shrinkage ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TB Technology: general issues::TBX History of engineering and technology
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    Springer Nature | Springer Berlin Heidelberg
    Publication Date: 2024-04-11
    Description: Dieses Buch ist eine Open-Access-Publikation unter einer CC BY 4.0 Lizenz. Wie können wir die digitale Transformation in der Wirtschaft bewältigen und dabei die Souveränität von allen Beteiligten fördern? Dieser Frage widmet sich der Band des Instituts für Innovation und Technik (iit) zum gleichnamigen Symposium mit dem Titel „Digitalisierung souverän gestalten – Innovative Impulse im Maschinenbau“. Er enthält elf Beiträge von Expert:innen verschiedenster Disziplinen. Betrachtet werden darin Herausforderungen und Lösungsansätze für Unternehmen und ihre Beschäftigten, aber auch politische Akteure und Intermediäre wie etwa Verbände. Zu den Themen gehören beispielsweise Kompetenzen für digitalisierte Arbeitsplätze, maschinelles Lernen zur Programmierung von Werkzeugmaschinen, künstliche Intelligenz in der Produktentstehung, aber auch plattformbasierte Dienstleistungen oder Geschäftsmodelle im Werkzeugmaschinenbau. Darüber hinaus werden übergreifende juristische Fragen ebenso aufgegriffen wie Implikationen für den Standort Deutschland.
    Keywords: Mechanical Engineering ; Business and Management, general ; Industrial Organization ; Innovation and Technology Management ; Digitale Souveränität ; Werkzeugmaschinenbau ; Künstliche Intelligenz ; Geschäftsmodelle ; Maschinelles Lernen ; Mensch-Maschine-Interaktionen ; Arbeitsplatzgestaltung ; Open Access ; Business & Management ; Economics of industrial organisation ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TG Mechanical engineering and materials::TGB Mechanical engineering ; thema EDItEUR::K Economics, Finance, Business and Management::KJ Business and Management ; thema EDItEUR::K Economics, Finance, Business and Management::KC Economics::KCD Economics of industrial organization
    Language: German
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    Frontiers Media SA
    Publication Date: 2024-04-04
    Description: The Frontiers in Chemistry Editorial Office team are delighted to present the inaugural “Frontiers in Chemistry: Rising Stars” article collection, showcasing the high-quality work of internationally recognized researchers in the early stages of their independent careers. All Rising Star researchers featured within this collection were individually nominated by the Journal’s Chief Editors in recognition of their potential to influence the future directions in their respective fields. The work presented here highlights the diversity of research performed across the entire breadth of the chemical sciences, and presents advances in theory, experiment and methodology with applications to compelling problems. This Editorial features the corresponding author(s) of each paper published within this important collection, ordered by section alphabetically, highlighting them as the great researchers of the future. The Frontiers in Chemistry Editorial Office team would like to thank each researcher who contributed their work to this collection. We would also like to personally thank our Chief Editors for their exemplary leadership of this article collection; their strong support and passion for this important, community-driven collection has ensured its success and global impact.
    Keywords: Green and Sustainable Chemistry ; Analytical Chemistry ; Theoretical and Computational Chemistry ; Polymer Chemistry ; Medicinal and Pharmaceutical Chemistry ; Organic Chemistry ; Nanoscience ; Catalysis and Photocatalysis ; Supramolecular Chemistry ; Electrochemistry ; Inorganic Chemistry ; Chemical Biology ; thema EDItEUR::P Mathematics and Science::PD Science: general issues
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2023-12-21
    Description: In dieser Arbeit wird einerseits die Lebensdauer der LEDs im System aus der Datenblattangabe der Hersteller und dem gemessenen Betriebspunkt in Abhängigkeit der Umgebungstemperatur berechnet. Alternativ wird die Lichtstromdegradation des Gesamtsystems über mehrere tausend Stunden gemessen und auf den L70-Wert extrapoliert. Um dabei den Messfehler aufgrund mangelnder thermischer Stabilisierung zu eliminieren, wurde eine Methode zur analytischen Beschreibung der Stabilisierung entwickelt.
    Keywords: T1-995 ; Temperatur ; Lebensdauer ; Messung ; LED ; Stabilisierung ; bic Book Industry Communication::T Technology, engineering, agriculture::TB Technology: general issues
    Language: German
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    Springer Nature | Springer International Publishing
    Publication Date: 2024-04-04
    Description: This open access textbook, like Rayleigh’s classic Theory of Sound, focuses on experiments and on approximation techniques rather than mathematical rigor. The second edition has benefited from comments and corrections provided by many acousticians, in particular those who have used the first edition in undergraduate and graduate courses. For example, phasor notation has been added to clearly distinguish complex variables, and there is a new section on radiation from an unbaffled piston. Drawing on over 40 years of teaching experience at UCLA, the Naval Postgraduate School, and Penn State, the author presents a uniform methodology, based on hydrodynamic fundamentals for analysis of lumped-element systems and wave propagation that can accommodate dissipative mechanisms and geometrically-complex media. Five chapters on vibration and elastic waves highlight modern applications, including viscoelasticity and resonance techniques for measurement of elastic moduli, while introducing analytical techniques and approximation strategies that are revisited in nine subsequent chapters describing all aspects of generation, transmission, scattering, and reception of waves in fluids. Problems integrate multiple concepts, and several include experimental data to provide experience in choosing optimal strategies for extraction of experimental results and their uncertainties. Fundamental physical principles that do not ordinarily appear in other acoustics textbooks, like adiabatic invariance, similitude, the Kramers-Kronig relations, and the equipartition theorem, are shown to provide independent tests of results obtained from numerical solutions, commercial software, and simulations. Thanks to the Veneklasen Research Foundation, this popular textbook is now open access, making the e-book available for free download worldwide. Provides graduate-level treatment of acoustics and vibration suitable for use in courses, for self-study, and as a reference Highlights fundamental physical principles that can provide independent tests of the validity of numerical solutions, commercial software, and computer simulations Demonstrates approximation techniques that greatly simplify the mathematics without a substantial decrease in accuracy Incorporates a hydrodynamic approach to the acoustics of sound in fluids that provides a uniform methodology for analysis of lumped-element systems and wave propagation Emphasizes actual applications as examples of topics explained in the text Includes realistic end-of-chapter problems, some including experimental data, as well as a Solutions Manual for instructors. Features “Talk Like an Acoustician“ boxes to highlight key terms introduced in the text.
    Keywords: Acoustics ; Engineering Acoustics ; Mechanical Engineering ; Waves in fluids ; Acoustics textbook ; Elastic waves ; Physical acoustics ; Electroacoustic transduction ; Acoustic radiation ; Harmonic oscillators ; Acoustic wave propagation ; Approximation techniques ; Similitude in acoustics and vibration ; Modes of enclosures ; Waveguides ; Nonlinear acoustics ; Acoustic levitation ; Open Access ; Wave mechanics (vibration & acoustics) ; Acoustic & sound engineering ; bic Book Industry Communication::P Mathematics & science::PH Physics::PHD Classical mechanics::PHDS Wave mechanics (vibration & acoustics) ; bic Book Industry Communication::T Technology, engineering, agriculture::TT Other technologies & applied sciences::TTA Acoustic & sound engineering ; bic Book Industry Communication::T Technology, engineering, agriculture::TG Mechanical engineering & materials::TGB Mechanical engineering ; thema EDItEUR::P Mathematics and Science::PH Physics::PHD Classical mechanics::PHDS Wave mechanics (vibration and acoustics) ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TT Other technologies and applied sciences::TTA Acoustic and sound engineering ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TG Mechanical engineering and materials::TGB Mechanical engineering
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    Springer Nature | Springer Berlin Heidelberg
    Publication Date: 2024-04-14
    Description: Gegenstand dieser Open Access Publikation sind die Auswirkungen automatisierter und vernetzter Fahrzeuge auf die Europäische Stadt sowie die Voraussetzungen, unter denen diese Technologie einen positiven Beitrag zur Stadtentwicklung leisten kann. Dabei vertreten die Autorinnen und Autoren zwei Thesen, die im wissenschaftlichen Diskurs bislang wenig Beachtung fanden: Automatisierte und vernetzte Fahrzeuge werden sich für lange Zeit nicht in allen Teilräumen der Stadt durchsetzen. Dies hat zur Folge, dass bislang angenommene Wirkungen - von der Verkehrssicherheit bis zur Verkehrsleistung sowie räumliche Effekte - neu bewertet werden müssen. Um einen positiven Beitrag dieser Technologie zur Mobilität der Zukunft sicherzustellen, müssen verkehrs- und siedlungspolitische Regulationen weiterentwickelt werden. Etablierte territoriale, institutionelle und organisatorische Grenzen sind zeitnah zu hinterfragen. Trotz oder wegen der bestehenden großen Unsicherheiten befinden wir uns am Beginn einer Phase des Gestaltens - in der Technologieentwicklung, aber eben auch in der Politik, Stadtplanung, Verwaltung und der Zivilgesellschaft.
    Keywords: Automotive Engineering ; Mechanical Engineering ; Autonomes Fahren ; Automatisiertes Fahren ; Automatisiertes und vernetztes Fahren ; Verkehrswende ; Stadtentwicklung ; Open Access ; Europäische Stadt ; Automotive technology & trades ; Automotive (motor mechanic) skills ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TR Transport technology and trades::TRC Automotive technology and trades ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TG Mechanical engineering and materials::TGB Mechanical engineering
    Language: German
    Format: image/png
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    facet.materialart.
    Unknown
    Springer Nature | Springer Singapore
    Publication Date: 2021-02-10
    Description: This open access book presents a series of complicated hydraulic phenomena and related mechanism of high-speed flows in head-head dam. According to the basic hydraulic theory, detailed experiments and numerical simulations, microscopic scale analysis on cavitation bubbles, air bubbles, turbulent eddy vortices and sand grains are examined systemically. These investigations on microscopic fluid mechanics, including cavitation erosion, aeration protection, air–water flow, energy dissipation and river-bed scouring, allow a deep understanding of hydraulics in high-head dams. This book provides reference for designers and researchers in hydraulic engineering, environment engineering and fluid mechanics.
    Keywords: Geoengineering, Foundations, Hydraulics ; Civil Engineering ; Mechanical Engineering ; Hydraulic Engineering ; Hydraulics ; High-head Dam ; Cavitation Erosion ; Aeration Protection ; Air-water Flow ; Energy Dissipation ; Scouring ; Sediment Transport ; Open Access ; Meteorology & climatology ; Geochemistry ; Civil engineering, surveying & building ; bic Book Industry Communication::R Earth sciences, geography, environment, planning::RB Earth sciences::RBP Meteorology & climatology ; bic Book Industry Communication::T Technology, engineering, agriculture::TN Civil engineering, surveying & building ; bic Book Industry Communication::T Technology, engineering, agriculture::TG Mechanical engineering & materials::TGB Mechanical engineering
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2019-05-18
    Description: An overview of liquid penetrant testing at Goddard Space Flight Center and an introduction of the author to the NASA Engineering and Safety Center Nondestructive Evaluation Technical Discipline Team is provided, including author biography, an overview of NASA spaceflight customers and their applications, a high-level description of research and development initiatives, two case-studies of flight project applications, and an introduction to the rest of the Goddard Space Flight Center Nondestructive Evaluation team and their respective roles in the organization.
    Keywords: Mechanical Engineering
    Type: GSFC-E-DAA-TN68554
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2019-06-25
    Description: Finite element simulation was employed in modeling the ultrasound (UT) pressure pulse propagation through a coupled liquid-composite medium to reproduce experimental data. From the simulation point of view, the proposed approach is challenging when there is a large simulation domain. For example, it is shown that a sub-micron wavelength of an ultrasonic wave requires a mesh size of several microns and this in turn requires significant computational resources, as well as special care in modeling. Some of the simulation results are presented considering that such modeling should reproduce experimental data for a healthy and faulty composite structure with complex geometry. Many possible experimental setups are simulated to demonstrate the non-destructive testing technique. This setup includes the generation of pressure pulse propagating through the tested composite plate and possible scattering by discontinuities (area of different impedance) that may be present in the panel. This scattered pulse together with the baseline pressure pulse generates a signature on the probe element which can be used to locate the position of defects in the structures.
    Keywords: Mechanical Engineering
    Type: NASA/TM-2019-220197 , ARC-E-DAA-TN67907
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2019-07-20
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: M19-7183 , Nuclear and Emerging Technologies for Space (NETS) 2019; Feb 25, 2019 - Feb 28, 2019; Pasco, WA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Publication Date: 2019-07-23
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: M19-7406 , Space Craft and Launch Vehicle (SCLV) Workshop; Jun 04, 2019 - Jun 06, 2019; El Segundo, CA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2019-07-25
    Description: Comparing "static equivalent" load cases from a PSD curve and fundamental frequencies between a NX Nastran SIM and a physical model.
    Keywords: Mechanical Engineering
    Type: KSC-E-DAA-TN69825
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Publication Date: 2019-07-25
    Description: Poster presentation for the Pathways summer intern showcase. Describes thermal desktop model simulating ISS orbit for a CubeSat scientific mission. The purpose of the simulation is to reaffirm the expected temperature range of some thermal coating samples compared to the state-of-the-art coatings currently used.
    Keywords: Mechanical Engineering
    Type: KSC-E-DAA-TN69826 , Summer Pathways Intern Showcase; Jul 17, 2019; Cocoa Beach, FL; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Publication Date: 2019-07-20
    Description: Small bore (6.35 millimeter) bushings, made from NASA PM400 solid lubricant composite, were evaluated in oscillatory sliding contact against a nickel-based superalloy shaft. Tests were conducted in air from 25 to 900 degrees Centigrade for extended periods (1 million cycles, plus or minus 15 degrees, 1 hertz) to assess the suitability of PM400 in gas turbine and reciprocating engine exhaust gas path control valve applications. Operating torque and estimated friction was monitored throughout the test duration and wear was measured at the end of test. In general, friction, torque and wear was low. At temperatures above 600 degrees Centigrade, bushing dimensional stability was achieved via short duration pre-test furnace exposure heat treatments. Preliminary test results show that bushings made from NASA PM400 are feasible for aerospace and industrial applications.
    Keywords: Mechanical Engineering
    Type: NASA/TM-2019-220038 , E-19637 , GRC-E-DAA-TN63032 , 2018 Tribology Frontiers Conference; 28ý31 Oct. 2018; Chicago, IL; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Publication Date: 2019-07-13
    Description: This presentation presents measurements of the efficiency of NASA's 2nd magnetic gear prototype. A detailed discussion of the test rig used to make these measurements was presented, including a thorough uncertainty analysis. The reported uncertainties are 95% confidence intervals that include the effects of temperature and parasitic loads. The prototype's response was measured at output speeds between 124 rpm and 744 rpm for a controlled output torque of 10 Nm (8% of the prototype's maximum torque). After correcting for tare losses, the prototype's efficiency was found to decrease from 90.0% to 83.0% as speed increased. If the efficiency is extrapolated to a typical operating condition (85% of maximum torque) using the good assumption that energy loss is approximately independent of the transmitted torque,the expected efficiency would be 99.0% to 98.4%, which exceeds the state of the art for these speeds.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN68758 , Vertical Flight Society''s Annual Forum & Technology Display; May 13, 2019 - May 16, 2019; Philadelphia, PA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2019-07-13
    Description: NASA has developed and commercialized high temperature coatings and bearings for extreme conditions. These technologies are now under consideration by industry for automotive applications such as turbochargers, fuel cell compressors and exhaust gas path mechanism applications. In this presentation, a review of Oil-Free technologies and their current state-of-development is introduced. Key NASA contributions to the field as documented by patents, research papers and technology demonstrations is also presented.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN50940 , Schaeffler International Bearing Meeting; Jan 25, 2018; Herzogenaurach; Germany
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2019-07-30
    Description: Growing interest in liquefied natural gas (LNG) as a rocket fuel necessitates a greater technical understanding of the compositional changes due to preferential boil-off (or weathering) that occurs during long duration storage. The purity of methane in LNG can range from 90 to 98%, and is subject to preferential boil-off due to its low boiling point compared to other constituents despite the use of high-performance thermal insulation systems. Active heat extraction (i.e. refrigeration) is required to completely eliminate weathering. For future operational safety and reliability, and to better understand the quality and efficiency of the LNG as a cryofuel, a 400-liter Cryostat vessel was designed and constructed to measure the composition and temperatures of the LNG at a number of different liquid levels over long durations. The vessel is the centerpiece of a custom-designed lab-scale integrated refrigeration and storage (IRaS) system employing a pulse tube cryocooler capable of roughly 50 W of lift at 100 K. Instrumentation includes ten temperature sensors mounted on a vertical rake and five liquid sample tubes corresponding to five liquid levels. Two modes of operation are studied. The first is without refrigeration in order to determine a baseline in the change in composition, and to study stratification of the LNG. The second is performed with the cryocooler active to determine the operational parameters of the IRaS system for eliminating the weathering as well as stratification effects in the bulk liquid. The apparatus design and test method, as well as preliminary test results are presented in this paper. As a bonus in cost-saving and operational efficiency, the capability of the IRaS system to provide zero-loss capabilities such as zero boil-off (ZBO) keeping of the LNG and zero-loss filling/transfer operations are also discussed.
    Keywords: Mechanical Engineering
    Type: KSC-E-DAA-TN70732 , Cryogenic Engineering Conference and International Cryogenic Materials Conference; Jul 21, 2019 - Jul 25, 2019; Hartford, CT; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Publication Date: 2019-08-24
    Description: A method is provided for installing a valve seat in the hole of a valve element. The valve seat is fabricated from a seal material having a freezing temperature. The seal material is stretched such that a portion thereof has a reduced diameter that is less than the diameter of the valve element's hole. The stretched portion of the seal material is immersed in a first environment having a temperature that is less than the freezing temperature of the seal material to thereby freeze the stretched portion and fix its reduced diameter. The stretched and frozen portion is then placed in the valve element's hole with the combination then being placed in a second environment having a temperature that is greater than the freezing temperature of the seal material.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2019-08-17
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: MSFC-E-DAA-TN70796
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Publication Date: 2019-08-27
    Description: The High Efficiency Megawatt Motor (HEMM) is being designed to meet the needs of Electrified Aircraft Propulsion (EAP). A preliminary design has been completed and risk reduction activities are being conducted in three key areas: cryogenic cooler design, superconducting rotor coil design and manufacturing, and stator thermal management. The key objective of HEMM is to establish a motor technology which simultaneously attains high specific power (〉16kW/kg ratio to electromagnetic weight) and high efficiency (〉98%) by judicious application of high temperature superconducting wire and integrated thermal management. Another important feature is to achieve the performance goals with an eye to aircraft integration constraints. An electromagnetic analysis was performed which shows that the proposed HEMM design meets the performance objectives if key current capability and mechanical constraints are achieved. The risk reduction activities are the first assessment of the key design features. The HEMM technology could be applied to a range of aircraft types that require megawatt level electrical power.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN70031 , AIAA/IEEE Electric Aircraft Technologies Symposium (EATS); Aug 22, 2019 - Aug 24, 2019; Indianapolis, IN; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Publication Date: 2019-08-30
    Description: New materials in recent decades have enabled advances in thermal insulation systems for storage and transfer of cryogens. To preserve the cold and achieve efficient cryogenic systems, a combination of materials, testing, and engineering is required. The total heat leak into any cryogenic assembly is comprised of three main parts: 1) heat leak through the insulation, 2) heat leak through the support structures, and 3) heat leak attributed to piping penetrations and feedthroughs (and their negative effects on the insulation). This "cold triangle" approach provides a basis for evaluating performance benefits of new materials and analyzing the cost effectiveness in overall system design. Provided are thermophysical data for aerogels, aerogel composites, novel multilayered composites, and glass bubbles for standard test conditions of 293 K and 78 K under conditions from high vacuum to ambient pressure. Examples of cryogenic storage tanks show the relative importance of both insulation and structural materials for achieving designs of highest energy efficiency.
    Keywords: Mechanical Engineering
    Type: KSC-E-DAA-TN72044 , IIR International Congress of Refrigeration (ICR 2019); Aug 24, 2019 - Aug 30, 2019; Montreal, Quebec; Canada
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Publication Date: 2019-09-07
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: M19-7559 , Thermal & Fluids Analysis Workshop (TFAWS 2019); Aug 26, 2019 - Aug 30, 2019; Hampton, VA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Publication Date: 2019-09-07
    Description: Additive manufacturing (AM) is being investigated at NASA and across much of the rocket propulsion industry as an alternate fabrication technique to create complex geometries for liquid engine components that offers schedule and cost saving opportunities. The geometries that can be created using AM offer a significant advantage over traditional techniques. Internal complexities, such as internal coolant channels for combustion chambers and nozzles that would typically require several operations to manufacture traditionally can be fabricated in one process. Additionally, the coolant channels are closed out as a part of the AM build process, eliminating the complexities of a traditional process like brazing or plating. The primary additive manufacturing technique that has been evaluated is powder bed fusion (PBF), or selective laser melting (SLM), but there is a scale limitation for this technique. There are several alternate additive manufacturing techniques that are being investigated for large-scale nozzles and chambers including directed energy deposition (DED) processes. A significant advantage of the DED processes is the ability to adapt to a robotic or gantry CNC system with a localized purge or purge chamber, allowing unlimited build volume. This paper will discuss the development and hot-fire testing of channel-cooled nozzles fabricated utilizing one form of DED called blown powder deposition. This initial development work using blown powder DED is being explored to form the entire channel wall nozzle with integral coolant channels within a single AM build. Much of this development is focused on the design and DED-fabrication of complex and thin-walled features and on characterization of the materials properties produced with this techniques in order to evolve this process. Subscale nozzles were fabricated using this DED technique and hot-fire tested in Liquid Oxygen/Hydrogen (LOX/GH2) and LOX/Kerosene (LOX/RP-1) environments accumulating significant development time and cycles. The initial materials that were evaluated during this testing were high-strength nickel-based Inconel 625 and JBK-75. Further process development is being completed to increase the scale of this technology for large-scale nozzles. This paper will summarize the general design considerations for DED, specific channel-cooled nozzle design, manufacturing process development, property development, initial hot-fire testing and future developments to mature this technology for regeneratively-cooled nozzles. An overview of future development at NASA will also be discussed.
    Keywords: Mechanical Engineering
    Type: M19-7539 , AIAA/SAE/ASEE Joint Propulsion Conference 2019; Aug 19, 2019 - Aug 22, 2019; Indianapolis, IN; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Publication Date: 2019-09-06
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: M19-7498 , ASME Pressure Vessels and Piping Conference PVP2019; Jul 14, 2019 - Jul 19, 2019; San Antionio, TX; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Publication Date: 2019-09-10
    Description: Additive manufacturing (AM) is an advanced fabrication technique that is demonstrating tremendous potential to reduce fabrication lead times and costs for liquid rocket engine components. The additive manufacturing technology lends itself to fabricate components with complex features such as internal coolant channels in combustion chambers that would otherwise require complex manufacturing operations. A requirement for high performance engines is to use high conductivity, high strength materials such as copper-alloys for combustion chamber liners to provide adequate wall temperatures and meet subsequent structural margins. A further requirement of this configuration is to minimize weight by defining and fabricating material in discrete locations as required. NASA and Industry partner, Virgin Orbit, have been working to advance these technologies through development of bimetallic additive manufacturing techniques under a public-private partnership through NASAs Announcement of Collaborative Opportunity (ACO). This partnership is advancing a bimetallic hybrid additively manufactured combustion chamber that integrates Powder Bed Fusion (PBF), specifically Selective Laser Melting (SLM), and Directed Energy Deposition (DED) blown powder techniques to optimize the chamber materials and subsequent assembly. The SLM process is being developed for the combustion chamber liner to use copper-alloys GRCop-84 (Copper-Chrome-Niobium) or C-18150 (Copper-Chrome-Zirconium). The hybrid DED blown powder technology is used to apply an integrated structural jacket and manifolds using an Inconel 625 superalloy on the outer surface of the SLM copper liner. The hybrid DED technology being used on this program is a DMG Mori Seiki AM machining center which integrates the DED blown powder with an integral subtractive (traditional) machining to minimize overall setups. A series of chambers were fabricated using these techniques with GRCop-84/Inconel 625 and C-18150/Inconel and hot-fire tested at NASA Marshall Space Flight Center (MSFC) in LOX/Kerosene (RP-1). This paper describes the process development to integrate these AM technologies into an integrated bimetallic assembly, the design of the chamber, results from hot-fire testing, and further development.
    Keywords: Mechanical Engineering
    Type: M19-7585 , AIAA Propulsion and Energy Forum and Exposition; Aug 19, 2019 - Aug 22, 2019; Indianapolis, IN; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Publication Date: 2019-10-31
    Description: 17-4 is used regularly to manufacture force transducers particularly for wind tunnel testing. Such applications place demanding structural requirements on the transducers with static safety factors of 1.5 common and the potential for additional dynamic loads. Additive manufacturing (AM) of transducers is very appealing because of significant potential cost and time savings as well as increased design flexibility. This study looks at the processing of 17-4 powder using selective laser melting by two different facilities using their own best practices. Hot isostatic pressing (HIP) is used by both facilities as part of the thermomechanical processing following printing to explore whether it can improve the consistency of mechanical properties. Results revealed that HIP reduced average porosity of 17-4 parts and that the yield strength of parts following solutionization and aging met wrought material property targets. Strain to failure of one of the facilities parts was less than 5% compared to greater than 9% for the other facility. Inspection of failure surfaces revealed this discrepancy could be attributed to pores (2-4% area fraction) on the failure surface of the low ductility parts. Phase content varied between the facilities with one facility producing fully martensitic parts and the other containing some retained austenite. The phase content of the starting powder and a slower than air cooling rate following the final heat treatment above the austenite eutectoid temperature are likely sources of the retained austenite. Taken together these results suggest that the current state of the art in AM 17-4 processing is sufficient for many NASA force measurement applications, but that attention is required at each stage of processing to assure desired mechanical properties.
    Keywords: Mechanical Engineering
    Type: NF1676L-32336 , Journal of Materials Engineering and Performance (ISSN 1059-9495) (e-ISSN 1544-1024); 28; 8; 4943-4951
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Publication Date: 2019-10-30
    Description: Magnetic gears present significant structural design challenges, because metallic/electrically conductive structures are highly undesirable as they would lead to significant efficiency reductions. Additionally, most non-electrically conductive structural materials have low thermal conductivity, which makes cooling the gear difficult. These limitations are of particular significant in magnetic gear's modulator structures. NASA Glenn has shown that pole pieces on the order of 1 to 2 mm thick optimize magnetic gears specific torque. These thin pole pieces however see very large magnetic forces and modulator structural limitations prevent the use of magnetically optimum pole pieces. The best solution to this issue to date has been the use of carbon fiber retaining rings on the external surface of the modulator, however this solution increases ring modulator airgap, resulting in a torque reduction from the optimum design. The pole pieces are also the largest sources of losses in magnetic gears. Because the modulator is nestled between the ring and sun gear extraction of this heat is a difficult problem and the modulator structure has to be designed to dissipate this heat load. In the presentation I will present the design of NASA Glenn's 4th magnetic gear's modulator in detail that uses a combination of 3D fiber reinforced nylon, IM7 carbon fiber, and pitch base cn80 fiber to close both structurally and thermally.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN72797 , Slams 2019; Sep 09, 2019 - Sep 13, 2019; Palmdale, CA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Publication Date: 2019-10-23
    Description: The soft capture system of the NASA Docking System (NDS) is a mechanism with six-degrees of freedom (6DOF). Although the nominal motion of the system is simple and largely in a single degree of freedom, complex movement is permissible within the requirements for docking. As such it is critical in the design, test, and verification of the docking system to fully understand the range of possible movement of the mechanism. This range of motion (ROM) must be large enough to accommodate all permitted docking sequences without internal collisions. This paper will discuss the methods used to perform these analysis for the NDS. Additionally, the testing sequences derived from this analysis will be presented, as illustrated in Figure 1. Finally, lessons learned from the analysis and test program will be discussed.
    Keywords: Mechanical Engineering
    Type: JSC-E-DAA-TN64241 , European Space Mechanisms and Tribology Symposium (ESMATS); Sep 18, 2019 - Sep 20, 2019; Munich; Germany
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Publication Date: 2019-11-09
    Description: This presentation presents measurements of the efficiency of NASA's 2nd magnetic gear prototype. A detailed discussion of the test rig used to make these measurements was presented, including a thorough uncertainty analysis. The reported uncertainties are 95% confidence intervals that include the effects of temperature and parasitic loads. The prototype's response was measured at output speeds between 124 rpm and 744 rpm for a controlled output torque of 10 Nm (8% of the prototype's maximum torque). After correcting for tare losses, the prototype's efficiency was found to decrease from 90.0% to 83.0% as speed increased. If the efficiency is extrapolated to a typical operating condition (85% of maximum torque) using the good assumption that energy loss is approximately independent of the transmitted torque,the expected efficiency would be 99.0% to 98.4%, which exceeds the state of the art for these speeds.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN73438 , Propulsion and Power Technical Meeting; Oct 29, 2019 - Oct 30, 2019; Hampton, VA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Publication Date: 2019-12-17
    Description: Multi-layer insulation (MLI) blankets covering the Hubble Space Telescope (HST) electronics bays were removed during HST Servicing Mission 4 and returned to Earth for analysis. The NASA Orbital Debris Program Office obtained HST Bay 5, 8, and 10 MLI blankets to characterize impact features and develop a flux estimate based on those features. This paper reports on the impact feature phenomenology observed during imaging campaigns in 2011 and 2018. Earlier conventions of measuring impacted features by recording the largest diameter to determine impacting particle size do not provide the best subsequent estimation of the impacting particle size. Instead of an impacted feature as a smooth-edged through-hole, a petaling phenomenon along with multiple-layering composition in impacted features has been observed in both hypervelocity testing and in the Bay 5 MLI. A new methodology of characterization techniques used during research and analysis of the HST MLI is presented, which will provide greater understanding and a more accurate estimation of impacting particles and their parameters.
    Keywords: Mechanical Engineering
    Type: JSC-E-DAA-TN74838 , International Orbital Debris (IOC) Conference; Dec 09, 2019 - Dec 12, 2019; Sugar Land, TX; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Publication Date: 2019-12-11
    Description: Over the last few decades, advances in high-performance computing, new materials characterization methods, and, more recently, an emphasis on integrated computational materials engineering (ICME) and additive manufacturing have been a catalyst for multiscale modeling and simulation-based design of materials and structures in the aerospace industry. As a result, NASA's Transformational Tools and Technology (TTT) Project sponsored a study (performed by a team led by Pratt & Whitney) to define the potential 25-year future state required for integrated multiscale modeling of materials and systems (e.g., load-bearing structures) to accelerate the pace and reduce the expense of innovation in future aerospace and aeronautical systems. This talk will briefly review the findings of this 2040 Vision study (e.g., the 2040 vision state; the required interdependent core technical work areas, Key Element (KE); associated critical gaps and actions to close those gaps; and major recommendations). The study, NASA CR 2018- 219771, envisions the development of a cyber-physical-social ecosystem comprised of experimentally verified and validated computational models, tools, and techniques, along with the associated digital tapestry, that marries two non-mutually exclusive paradigms _ "design of the materials" (material scientist viewpoint) and "design with the materials" (structural analyst viewpoint) _ into a concurrent transformational paradigm that impacts the entire supply chain to enable cost-effective, rapid, and revolutionary design of fit-for-purpose materials, components, and systems. Although the vision focused on aeronautics and space applications, it is believed that other engineering communities (e.g., automotive, biomedical, etc.) can benefit as well from the proposed framework with only minor modifications. Finally, it is TTT's hope and desire that this vision provides the strategic guidance to both public and private research and development decision makers to make the proposed 2040 vision state a reality and thereby provide a significant advancement in the United States global competitiveness.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN73355 , Model-Based Engineering: What Is It & How Will It Impact Engineering Simulation?; Oct 01, 2019; Columbus, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Publication Date: 2019-07-13
    Description: NASA's Approach to Additive Manufacturing Certification: Methodologies for Qualification of Additively Manufactured Aerospace Hardware. This course is intended to provide guidance and practical methodologies on how to establish a qualified process and deliver certifiable hardware per the requirements in MSFC-STD-3716 and MSFC-SPEC-3717. Course Objectives: Reinforce a basic understanding of AM processes; Become familiar with MSFC-STD-3716 and MSFC-SPEC-3717 requirements for metallic spaceflight hardware; Appreciate integrated path to Qualification and Certification; Understand products necessary to get you to Qualification and Certification.
    Keywords: Mechanical Engineering
    Type: M19-7321 , Aircraft Airworthiness & Sustainment Conference (AA&S 2019) Training Course; Apr 23, 2019 - Apr 26, 2019; Washington, DC; United States
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: NASAs In Space Manufacturing Initiative (ISM): The Case for ISM - Why; ISM Path to Exploration; In Space Robotic Manufacturing and Assembly (IRMA). Additive Manufacturing (AM) Development For Liquid Rocket Engine Space Flight Hardware. MSFC (Marshall Space Flight Center) Standard and Specification For Additively Manufactured Space Flight Hardware.
    Keywords: Mechanical Engineering
    Type: MSFC-E-DAA-TN67521 , Aerospace Innovative Technology Summit (AITS); May 07, 2019 - May 09, 2019; Birmingham, AL; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Publication Date: 2019-07-13
    Description: We describe analytical methods for the design of the discrete elements of ultralight lattice structures. This modular, building block strategy allows for relatively simple element manufacturing, as well as relatively simple robotic assembly of low mass density structures on orbit, with potential for disassembly and reassembly into highly varying and large structures. This method also results in a structure that is easily navigable by relatively small mobile robots. The geometry of the cell can allow for high packing efficiency to minimize wasted payload volume while maximizing structural performance and constructability. We describe the effect of geometry choices on the final system mechanical properties and automated robotic constructability of a final system. Geometric properties considered include number of attachments per voxel, number of attachments per coefficient of volume, and effects of vertex, edge, and face connectivity of the unit cell. Mechanical properties considered include strength scaling, modulus scaling, and packing efficiency of the lattice. Automated constructibility metrics include volume allowance for an end-effector, strut clearance angle for an end-effector, and packing efficiency. These metrics were applied to six lattice unit cell geometries: cube, cuboctahedron, octahedron, octet, rhombic dodecahedron, and truncated octahedron. A case study is presented to determine the most suitable lattice system for a specific set of strength and modulus scaling requirements while optimizing for ease of robotic assembly.
    Keywords: Mechanical Engineering
    Type: ARC-E-DAA-TN62635 , Institute of Electrical and Electronics Engineers (IEEE) Aerospace Conference; Mar 02, 2019 - Mar 09, 2019; Big Sky, MT; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Publication Date: 2019-09-06
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: M19-7508
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Publication Date: 2019-09-06
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: M19-7454 , M19-7453 , Additive International Summit 2019; Jul 10, 2019 - Jul 11, 2019; Nottingham; United Kingdom|Aircraft Airworthiness and Sustainment Conference; Jul 23, 2019 - Jul 26, 2019; Brisbane, Queensland; Australia
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-09-13
    Description: The NASA Balloon Program Office (BPO), located at Wallops Flight Facility asked the Mechanical Systems Branch (Code 548) to improve the design of their balloon valve. BPO uses two main types of balloons, Zero Pressure Balloon (ZPB) and Super Pressure Balloon (SPB), which both use the valve. It is used for termination of the ZPB, and inflation and termination of the SPB. During launch campaigns the valve showed signs of helium leakage which lead the BPO to ask for an improvement. As part of a Professional Readiness Engineering Program (PREP), research and review of the current valve was conducted and a new design was prepared. The current custom designed valve consists of a "pie" plate that is actuated up and down via a gear rack that is driven by a globe motor. When closed the knife edge of the pie plate bites into a silicone gasket to seal the structure. Unfortunately, the gasket material permanently deforms after being compressed and the plate itself bends under the force induced by the motor, introducing two possible helium leak paths. The new custom designed valve utilizes o-rings instead of one gasket to reduce the possibility of leakage from permanent deformation. One o-ring seals the valve structure to its mating surface and a spring energized o-ring is used in a piston design to seal the valve once it's closed. The design also utilizes different materials to increase stiffness and strength so that it is less likely to bend under the force from the motor. Currently the new valve has finished the design and analysis phases and is proceeding towards manufacturing and testing.
    Keywords: Mechanical Engineering
    Type: GSFC-E-DAA-TN72381
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Publication Date: 2019-09-13
    Description: NASA Glenn Research Center is developing a 1.4 MW high-efficiency electric machine for future electrified aircraft to reduce energy consumption, emissions, and noise. This wound-field, synchronous machine employs a self-cooled, superconducting rotor to achieve excellent specific power and efficiency. This paper presents the progress made over the past year toward a critical design of the superconducting rotor, including refined analysis and risk reduction testing on prototype superconducting coils. A 3D finite element model of the rotor is developed to simulate the combined loading imposed by the initial cool down of the rotor from room temperature to cryogenic temperature and the subsequent rotation of the rotor up to the design speed. The model is evaluated to better predict the stress state in the critical components and the reduction in physical gap between the stator and rotor due to the resulting radial deflections. This model includes an enhanced model of the superconducting coil that considers the coil as an assembly of four individual coil layers. An improved coil fabrication process is described in detail. Two sub-scale test coils are fabricated and then tested under repeated thermal cycling between room temperature and liquid nitrogen temperature (77 K). It is demonstrated that the proposed coil fabrication procedure can produce no-insulation, high temperature superconducting coils that can survive several thermal cycles without apparent degradation.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN70698 , AIAA / IEEE Electric Aircraft Technologies Symposium (EATS); Aug 22, 2019 - Aug 24, 2019; Indianapolis, IN; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Publication Date: 2019-09-10
    Description: Additive manufacturing (AM) is an advanced fabrication technique that is demonstrating tremendous potential to reduce fabrication lead times and costs for liquid rocket engine components. The additive manufacturing technology lends itself to fabricate components with complex features such as internal coolant channels in combustion chambers that would otherwise require complex manufacturing operations. A requirement for high performance engines is to use high conductivity, high strength materials such as copper-alloys for combustion chamber liners to provide adequate wall temperatures and meet subsequent structural margins. A further requirement of this configuration is to minimize weight by defining and fabricating material in discrete locations as required. NASA and Industry partner, Virgin Orbit, have been working to advance these technologies through development of bimetallic additive manufacturing techniques under a public-private partnership through NASAs Announcement of Collaborative Opportunity (ACO). This partnership is advancing a bimetallic hybrid additively manufactured combustion chamber that integrates Powder Bed Fusion (PBF), specifically Selective Laser Melting (SLM), and Directed Energy Deposition (DED) blown powder techniques to optimize the chamber materials and subsequent assembly. The SLM process is being developed for the combustion chamber liner to use copper-alloys GRCop-84 (Copper-Chrome-Niobium) or C-18150 (Copper-Chrome-Zirconium). The hybrid DED blown powder technology is used to apply an integrated structural jacket and manifolds using an Inconel 625 superalloy on the outer surface of the SLM copper liner. The hybrid DED technology being used on this program is a DMG Mori Seiki AM machining center which integrates the DED blown powder with an integral subtractive (traditional) machining to minimize overall setups. A series of chambers were fabricated using these techniques with GRCop-84/Inconel 625 and C-18150/Inconel and hot-fire tested at NASA Marshall Space Flight Center (MSFC) in LOX/Kerosene (RP-1). This paper describes the process development to integrate these AM technologies into an integrated bimetallic assembly, the design of the chamber, results from hot-fire testing, and further development.
    Keywords: Mechanical Engineering
    Type: AIAA-2019-4390 , M19-7547 , AIAA Propulsion and Energy Forum and Exposition; Aug 19, 2019 - Aug 22, 2019; Indianapolis, IN; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Publication Date: 2019-10-11
    Description: NASA Glenn Research Center is developing a 1.4 MW high-efficiency electric machine for future electrified aircraft to reduce energy consumption, emissions, and noise. This wound-field, synchronous machine employs a self-cooled, superconducting rotor to achieve excellent specific power and efficiency. This paper presents the progress made over the past year toward a critical design of the superconducting rotor, including refined analysis and risk reduction testing on prototype superconducting coils. A 3D finite element model of the rotor is developed to simulate the combined loading imposed by the initial cool down of the rotor from room temperature to cryogenic temperature and the subsequent rotation of the rotor up to the design speed. The model is evaluated to better predict the stress state in the critical components and the reduction in physical gap between the stator and rotor due to the resulting radial deflections. This model includes an enhanced model of the superconducting coil that considers the coil as an assembly of four individual coil layers. An improved coil fabrication process is described in detail. Two sub-scale test coils are fabricated and then tested under repeated thermal cycling between room temperature and liquid nitrogen temperature (77 K). It is demonstrated that the proposed coil fabrication procedure can produce no-insulation, high temperature superconducting coils that can survive several thermal cycles without apparent degradation.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN72535 , AIAA / IEEE Electric Aircraft Technologies Symposium (EATS); Aug 22, 2019 - Aug 24, 2019; Indianapolis, IN; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2019-10-01
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: MSFC-E-DAA-TN73261
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Publication Date: 2020-01-17
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: MSFC-E-DAA-TN76087 , MSFC-E-DAA-TN76086
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Publication Date: 2020-01-17
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: ARC-E-DAA-TN75029 , Art + Nature Symposium; Nov 09, 2019 - Nov 10, 2019; Berkeley, CA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2019-07-12
    Description: A combustor assembly includes a first wall, a second wall, a bulkhead and a plurality of fuel injectors. The bulkhead forms a combustion chamber with the first and the second walls. The fuel injectors are configured with the first wall in a unique and/or a fluctuating pattern.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2019-07-20
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: M18-7133
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2019-07-19
    Description: Enhancement of a 2-stage light gas gun capability is under development at NASA Marshall Space Flight Center for the purpose of making rain impacts on nose cone and window materials. This paper will discuss current capabilities of this gun system and the path it took to get there. The end goal is to be able to provide realistic rain and thermal environments, simulating rain impact conditions of high speed flight (combined effects). In the past year, the ability to create impacts to simulate rain using 2, 3, and 4 mm Nylon beads in the 7,000-10,000 ft/s (2.13-3.05 km/s) range at room temperature has been demonstrated. It is desired to extend this range down to 6000 ft/s (1.83 km/s) for rain impact purposes. The size range capability will also be extended to launch particles 1 mm and smaller. In addition, a heating capability is being added to the system to potentially cover a temperature range from room temperature to 5000 F. Hydrogen light gas will extend the velocity range to 23,000-26,000 ft/s (7-8 km/s), simulating orbital debris impacts for vehicles that spend a significant amount of time in space. Particle impact precision will also be evaluated during this development process.
    Keywords: Mechanical Engineering
    Type: M18-6552 , Electromagnetic Windows Symposium; May 22, 2018 - May 25, 2018; Dayton, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Publication Date: 2019-07-20
    Description: NASA Glenn Research Center is developing a 1.4~MW high-efficiency electric machine for future electrified aircraft to reduce energy consumption, emissions, and noise. This wound-field, synchronous machine employs a self-cooled, superconducting rotor to achieve excellent specific power and efficiency. This paper discusses the fabrication of the no-insulation high temperature superconducting (HTS) coils and presents the lessons learned. The process is compared to the fabrication of conventionally insulated HTS coils. Testing of the coils' critical current at liquid nitrogen temperature is also presented. The influence of thermal cycling on the critical current and n-value is studied.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN58736 , AIAA/IEEE Electric Aircraft Technologies Symposium; Jul 09, 2018 - Jul 11, 2018; Cincinnati, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2019-07-13
    Description: Magnetic gearing is an alternative to mechanical gearing, where torque is transferred through magnetic force as opposed to contact force. The technology has the potential to be used in aircraft applications, without the lubrication, noise, and maintenance issues that can exist with mechanical gearing. Initial design and prototype development work was done at NASA to create a foundational understanding of the technology and the factors that influence its specific torque. The specific torque achieved through design optimization was found to be less than that of high-torque mechanical aircraft transmissions, but may be comparable to that of lower torque mechanical transmissions for electrified vertical takeoff and landing aircraft. The lessons learned from NASA's initial technology development and the direction of NASA's future work in field are discussed.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN56319 , AHS International''s Annual Forum and Technology Display; May 15, 2018 - May 17, 2018; Phoenix, AZ; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Publication Date: 2019-07-13
    Description: In addition to the highly visible astronauts, NASA personnel include thousands of engineers, scientists, technicians and support staff. These vital employees develop technologies and solution to the many problems the Agency faces while undertaking space exploration. Space telescopes present unusual technical challenges related to bearings and lubricants. In this presentation to to the Brunswick Astronomy Club, NASA technologies under development (e.g. NiTi bearings) that could someday alleviate space telescope mechanism problems will be reviewed and discussed.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN50944 , Brunswick Astronomy Club; Jan 11, 2018; Brunswick, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Publication Date: 2019-07-13
    Description: The NASA Docking System (NDS) Block 1 is a key component of NASA's vision for space exploration. It is designed to provide capability for visiting vehicles to dock to the International Space Station's recently-installed International Docking Adapter ports. It is the first docking system to be developed by NASA since the Apollo-Soyuz Test Project of the 1970's. The NDS Block 1 includes provisions for capture, structural attachment, power/data transfer, and undocking. It uses a direct-drive electromechanical Stewart Platform capture system architecture, along with an innovative automated control scheme, to achieve an unprecedented level of performance and simplicity. Its design implements the new International Docking System Standard, which will be a key enabler of diverse and flexible exploration missions in future iterations. NDS qualification was completed in 2017 to support a planned first flight in 2018 on the Boeing CST-100 Starliner.
    Keywords: Mechanical Engineering
    Type: JSC-E-DAA-TN51081 , Aerospace Mechanisms Symposium; May 16, 2018 - May 18, 2018; Cleveland, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Publication Date: 2019-07-13
    Description: NASA's strategic goal is to put humans on Mars in the 2030s. The NASA Human Spaceflight Architecture Team (HAT) and NASA Mars Design Reference Architecture (DRA) 5.0 has determined that in-situ resource utilization (ISRU) is an essential technology to accomplish this mission. Additive construction technology using in-situ materials from planetary surfaces will reduce launch mass, allow structures to be three dimensionally (3D) printed on demand, and will allow building designs to be transmitted digitally from Earth and printed in space. This will ultimately lead to elimination of reliance on structural materials launched from Earth (zero launch mass of construction consumables). The zero launch mass (ZLM) 3D print head project addressed this need by developing a system that 3D prints using a mixture of in-situ regolith and polymer as feedstock, determining the optimum mixture ratio and regolith particle size distribution, developing software to convert g-code into motion instructions for a FANUC robotic arm, printing test samples, performing materials testing, and printing a reduced scale habitable structure concept. This paper will focus on the ZLM 3D Print Head design, materials selection, software development, and lessons learned from operating the system in the NASA KSC Swamp Works Granular Mechanics & Regolith Operations (GMRO) Laboratory.
    Keywords: Mechanical Engineering
    Type: KSC-E-DAA-TN54777 , ASCE Earth and Space Conference; Apr 09, 2018 - Apr 12, 2018; Cleveland, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: M18-7024 , CMH-17 Additive Manufacturing Coordination Committee Meeting; Oct 16, 2018 - Oct 17, 2018; Wichita, KS; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: JSC-E-DAA-TN60395 , Thermal Fluids & Analysis Workshop (TFAWS) 2018; Aug 20, 2018 - Aug 24, 2018; Houston, TX; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Publication Date: 2019-07-13
    Description: Many different aerogel-based materials are now being used in thermal insulation systems for cryogenic applications. These materials include flexible composite blankets, bulk-fill particles, and polymer composites in both evacuated and non-evacuated environments. In ambient environments, aerogels provide superior thermal performance compared to conventional polymeric foam and cellular glass insulations while offering unique advantages in solving problems with weathering, moisture, and mechanical damage. Aerogels are also used as spacer materials in multilayer insulation systems. These layered systems provide combined structural-thermal capability for cryogenic systems in either vacuum-jacketed or externally-applied insulation designs. Test data (effective thermal conductivity) include a wide range of both commercial and experimental aerogel materials. Testing was performed using laboratory cryostats and standard methods including full range vacuum (from ambient pressure to high vacuum) and boundary temperatures 293 K and 78 K. Examples of aerogel-based insulation systems are given for both evacuated and non-evacuated applications.
    Keywords: Mechanical Engineering
    Type: KSC-E-DAA-TN60364 , International Cryogenic Engineering Conference; Sep 03, 2018 - Sep 07, 2018; Oxford; United Kingdom
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Publication Date: 2019-07-13
    Description: We present the current state of development for a continuous magnetic refrigeration system capable of cooling a detector array or other payload to temperatures below 50 mK. This adiabatic demagnetization refrigerator contains four-stages that are cycling continuously yet present a constant ultra-low temperature heat sink at one physical location within the refrigerator. Two different configurations of essentially the same cooler will be presented where the difference is in the physical layout of the stages and the type of heat sink used for the refrigerator's heat rejection.
    Keywords: Mechanical Engineering
    Type: GSFC-E-DAA-TN59560 , International Cryogenic Engineering Conference 2018; Sep 03, 2018 - Sep 07, 2018; Oxford; United Kingdom
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Publication Date: 2019-07-13
    Description: Many different aerogel-based materials are now being used in thermal insulation systems for cryogenic applications. These materials include flexible composite blankets, bulk-fill particles, and polymer composites in both evacuated and non-evacuated environments. In ambient environments, aerogels provide superior thermal performance compared to conventional polymeric foam and cellular glass insulations while offering unique advantages in avoiding problems with weathering, moisture, and mechanical damage. Aerogels are also used as spacer materials in multilayer insulation systems. These layered systems provide combined structural-thermal capability for cryogenic systems in either vacuum-jacketed or externally-applied insulation designs. Test data (effective thermal conductivity) include a wide range of both commercial and experimental aerogel materials. Testing was performed using laboratory cryostats and standard methods including full range vacuum (from ambient pressure to high vacuum) and boundary temperatures 293 K and 78 K. Examples of aerogel-based insulation systems are given for both evacuated and non-evacuated applications.
    Keywords: Mechanical Engineering
    Type: KSC-E-DAA-TN59921 , International Cryogenic Engineering Conference 2018; Sep 03, 2018 - Sep 07, 2018; Oxford; United Kingdom
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Publication Date: 2019-07-13
    Description: The pericyclic transmission provides the opportunity to vastly impact transmission design in rotorcraft due to its ability to provide exceedingly high reduction ratios in a single stage that would normally require multiple gear stages to produce. This could lead to lighter transmissions with fewer components, increased range, reliability, efficiency, speed and decreased cost to maintain. While many previous studies have focused upon the gearing within the pericyclic transmission, this work focused on what influences pericyclic geometry, and how changes in geometry impacts bearing loads. Specifically the loading of bearings that must deliver power from the input shaft to the nutating and rotating gears of the system were of primary concern. A comprehensive look at dynamic loads generated by nutating bodies was performed. Methods to address these dynamic loads via application of counterbalances and deviation from conventional pericyclic transmission designs were utilized to negate the dynamic moment of concern. Finally a static solver was used to determine the bearing loads with updated component geometries and mass moment of inertias that included the required counterbalances.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN54774 , AHS International Annual Forum & Technology Display; May 14, 2018 - May 17, 2018; Phoenix, AZ; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Publication Date: 2019-07-13
    Description: In addition to the highly visible astronauts, NASA personnel include thousands of engineers, scientists, technicians and support staff. These vital employees develop technologies and solution to the many problems the Agency faces while undertaking space exploration. In this presentation to STEM students, the engineering that has been done to develop and maintain critical mechanism on the International Space Station will be reviewed and discussed. The overall goal of the presentation is to clearly show that many individuals can make meaningful contributions to space exploration without ever leaving the earth.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN50942 , Schaeffler International Bearing Meeting; Jan 22, 2018; Herzogenaurach; Germany
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2019-07-13
    Description: A novel pin on disc tribometer was designed and constructed to generate a high-speed, wear coefficient database for hydrodynamic bearings that are typically used in canned motors found in the active thermal control circuits of robotic and inhabited spacecraft. The primary motivation for this work was the premature failure of the active external thermal control pump on the International Space Station in 2010. During the failure investigation of this incident, the root cause was postulated to be high speed wear of the bearings. Although a detailed forensic analysis gave credibility to this theory, the lack of wear coefficient data at relevant conditions prevented validation of this finding. The database generated from the new Extreme Environment Tribometer (EET) enabled a closure calculation within 5% of the observed wear from inspections of the failed hardware. Testing in anhydrous ammonia and surrogate fluid was performed to provide a means for simplified testing in the future and to populate a preliminary database for the design of future active thermal control systems on spacecraft. The EET and test techniques developed for the measurement of high-speed wear coefficients are available to future system designers.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN53046 , Aerospace Mechanisms Symposium; May 16, 2018 - May 18, 2018; Cleveland, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Publication Date: 2019-07-13
    Description: Mission Objective Study the origin and evolution of galaxies, stars planetary systems. Optimized for infrared observations
    Keywords: Mechanical Engineering
    Type: GSFC-E-DAA-TN56643 , SPIE Astronomical Telescopes & Instrumentation; Jun 10, 2018 - Jun 15, 2018; Austin, TX; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Publication Date: 2019-07-13
    Description: NASA Glenn Research Center is developing a 1.4 MW high-efficiency electric machine for future electrified aircraft to reduce energy consumption, emissions, and noise. This wound-field, synchronous machine employs a self-cooled, superconducting rotor to achieve excellent specific power and efficiency. The design of the superconducting rotor and the optimization of its electromagnetic and structural responses are analyzed in this paper. Candidate designs are evaluated in terms of absolute performance, specific performance, and performance per cost. It is found that optimizing the electromagnetic response for absolute or specific performance yields designs that are similar to each other, but opposite of the cost-optimized design. A method to define the thermal requirements of the superconducting coils and integrated cryocooler is also presented.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN58267 , AIAA Propulsion and Energy Forum; Jul 09, 2018 - Jul 11, 2018; Cincinnati, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Publication Date: 2019-07-13
    Description: The pericyclic transmission provides the opportunity to vastly impact transmission design in rotorcraft due to its ability to provide exceedingly high reduction ratios in a single stage that would normally require multiple gear stages to produce. This could lead to lighter transmissions with fewer components, increased range, reliability, efficiency, speed and decreased cost to maintain. While many previous studies have focused upon the gearing within the pericyclic transmission, this work focused on what influences pericyclic geometry, and how changes in geometry impacts bearing loads. Specifically the loading of bearings that must deliver power from the input shaft to the nutating and rotating gears of the system were of primary concern. A comprehensive look at dynamic loads generated by nutating bodies was performed. Methods to address these dynamic loads via application of counterbalances and deviation from conventional pericyclic transmission designs were utilized to negate the dynamic moment of concern. Finally a static solver was used to determine the bearing loads with updated component geometries and mass moment of inertias that included the required counterbalances.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN56075 , AHS International Annual Forum & Technology Display; May 14, 2018 - May 17, 2018; Phoenix, AZ; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Publication Date: 2019-07-13
    Description: NASA Glenn Research Center is developing a 1.4~MW high-efficiency electric machine for future electrified aircraft to reduce energy consumption, emissions, and noise. This wound-field, synchronous machine employs a self-cooled, superconducting rotor to achieve excellent specific power and efficiency. The design of the superconducting rotor and the optimization of its electromagnetic and structural responses are analyzed in this paper. Candidate designs are evaluated in terms of absolute performance, specific performance, and performance per cost. It is found that optimizing the electromagnetic response for absolute or specific performance yields designs that are similar to each other, but opposite of the cost-optimized design. A method to define the thermal requirements of the superconducting coils and integrated cryocooler is also presented.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN57405 , AIAA Propulsion & Energy; Jul 07, 2018 - Jul 13, 2018; Cincinnati, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Publication Date: 2019-07-13
    Description: Final Paper and not the abstract is attached. a summary of the Design, Development, and Qualification of the Capture Latch Assembly (CLA) for the NASA Docking System Block 1 (NDSB1). The CLA is an integral part of the Soft Capture System (SCS) of the NDSB1, serving the purpose of connecting the mating SCS Rings of two docking vehicles. The paper will present an overview of the function of the CLA and its basic concept of operations, including a summary of the major components of the CLA. The development, qualification, and production of the CLA will then be described. Particular focus will be provided on two major issues that occurred during production and qualification of the CLA. The first issue was failures of the CLA Motor (CLM) during acceptance testing (AT). The failures of the CLM were ultimately determined to be due to design defects and manufacturing errors in the motor commutation sensor assembly. The second issue was failure of the secondary release mechanism, or Contingency Capture Latch Release (CCLR) mechanism during development and qualification testing. The CCLR failures were found to be a result of excess free play in the release mechanism, resulting in wear leading to galling inside the release mechanism. An overview of each failure will be provided, along with a summary of the failure investigation and recovery process. Finally, Lessons Learned from each of the major issues and the overall development of the Capture Latch will be presented.
    Keywords: Mechanical Engineering
    Type: JSC-E-DAA-TN51644 , Aerospace Mechanisms Symposium; May 16, 2018 - May 18, 2018; Cleveland, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Publication Date: 2019-07-13
    Description: Examine set-to-set variability with 4 build sets with the same layout Establish the effect of solutioning heat treatments (HT) on as-fabricated grain structure and microstructure (gamma)-solvus= 1156 C (1) As-fabricated (2) 2 hour subsolvus HT(-15 C) + conventional 2-step aging (3, 4, 5) 0.5 hour, 2 hours, 4 hours supersolvus HT (+18 C) + 2 step aging Gain insight into location-specific microstructure to correlate later to mechanical properties (tensile, creep, LCF behavior)
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN53591 , (TMS 2018) Annual Meeting & Exhibition of the Minerals, Metals and Materials Society; Mar 11, 2018 - Mar 15, 2018; Phoenix, AZ; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Publication Date: 2019-07-27
    Description: The Advanced eLectrical Bus (ALBus) project is a technology demonstration mission of a 3-U CubeSat with an advanced, digitally controlled electrical power system capability and the novel use of Shape Memory Alloy (SMA) technology for reliable solar array deployable mechanisms. The ALBus cubesat has a need to deploy four solar arrays in addition to the body-mounted arrays on each side of the cubesat. A goal of the mission is to utilize the SMAs being developed at the NASA Glenn Research Center to deploy these solar arrays. The use of SMAs allows for the ability to test and reset the flight deployment mechanism prior to flight which reduces the risk of on orbit deployment failures common on cubesats. As a result, an SMA driven Retention and Release mechanism and an SMA driven hinge was designed, developed, and being prepared for flight. This paper summarized the development of these mechanisms, types and functionalities of SMAs used, and lessons learned throughout the process.
    Keywords: Mechanical Engineering
    Type: NASA/TM-2018- 219914 , E-19532 , GRC-E-DAA-TN54393 , Aerospace Mechanisms Symposium; 16ý18, May 2018; Cleveland, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Publication Date: 2019-08-24
    Description: An asymmetric mast is disclosed that can be used for solar arrays. The asymmetric mast can have an asymmetry out of the plane of the solar blanket. The mast may include two or more booms that comprise slit tube longerons. In some embodiments, a single mast can be used with one or two solar blankets.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Publication Date: 2019-08-24
    Description: A poppet valve system that includes a valve body having a first and second end and defining a valve cavity and a poppet assembly extending from the first end to the second end and through the valve cavity. The poppet assembly can include a movable poppet head disposed at the first end of the poppet assembly and configured generate a seal by contacting a portion of the valve body and configured to define an opening between the valve cavity and a pressure cavity. The poppet assembly can also include a movable guiding element disposed at the second end of the valve body and a shaft extending from the first end to the second end and coupled to the poppet head and guiding element.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Publication Date: 2019-08-13
    Description: The pericyclic transmission provides the opportunity to vastly impact transmission design in rotorcraft due to its ability to provide exceedingly high reduction ratios in a single stage that would normally require multiple gear stages to produce. This could lead to lighter transmissions with fewer components, increased range, reliability, efficiency, speed and decreased cost to maintain. While many previous studies have focused upon the gearing within the pericyclic transmission, this work focused on what influences pericyclic geometry, and how changes in geometry impacts bearing loads. Specifically the loading of bearings that must deliver power from the input shaft to the nutating and rotating gears of the system were of primary concern. A comprehensive look at dynamic loads generated by nutating bodies was performed. Methods to address these dynamic loads via application of counterbalances and deviation from conventional pericyclic transmission designs were utilized to negate the dynamic moment of concern. Finally a static solver was used to determine the bearing loads with updated component geometries and mass moment of inertias that included the required counterbalances.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN59816 , SLaMS ECF; Aug 21, 2018 - Aug 24, 2018; Greenbelt, MD; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Publication Date: 2019-08-13
    Description: For many materials used in space hardware, the environment in which they need to operate is harsher than the environment on earth. Exposure to vacuum conditions, atomic oxygen, and ultraviolet radiation can be detrimental, so testing of space hardware in simulated space environments is required. This is especially true for elastomeric components such as seals. NASA is developing advanced space-rated vacuum seals in support of future space exploration missions. These seals must exhibit extremely low leak rates to ensure that astronauts have sufficient breathable air during extended-duration missions. In some applications the seals are not mated during portions of the mission and are left uncovered and exposed to the conditions in space for prolonged periods of time prior to mating. Space-rated vacuum seals are often made of silicone because of the material's wide operating temperature range and ability to be molded or extruded into various shapes and cross sections. One approach being considered to achieve improved performance is to add titanium dioxide to the silicone material to make it more resistant to damage from ultraviolet radiation. In this study, seals made of the baseline material with and without 1.5 percent titanium dioxide additive (by weight) were exposed to atomic oxygen and increasing levels of ultraviolet radiation and then leak tested. Test results revealed that seals made of the new material could withstand longer exposures while still satisfying the leak rate requirement even under worst-case conditions of partial compression at the extremes of the anticipated operating temperature range.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN61101 , Space Simulation Conference; Nov 05, 2018 - Nov 08, 2018; Annapolis, MD; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-08-28
    Description: An electrohydrodynamic (EHD) pump increases refrigerant flow rate and the resulting pressure in a vapor compression based cooling system for permitting reduced compressor sizes and power demands. The EHD pump disposes electrodes in a liquid path of the refrigerant flow, and increases fluid flow and resulting pressure by an induced liquid flow between a pair of asymmetric electrodes. Voltage applied to these electrodes results in a conduction pumping mechanism associated with heterocharge layers in the vicinity of the electrodes based on disassociation of a neutral electrolyte species in the refrigerant fluid and recombination of the generated ions. The induced flow draws the liquid due to a net fluid flow toward one of the electrodes based on the asymmetry of the electrode pair. Electrodes are disposed on an inner surface of a refrigerant vessel, in communication with an annular liquid film that forms around the inner circumference in two-phase fluid systems.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Publication Date: 2019-08-28
    Description: A process for fabricating relatively thin SiC diaphragms may include fast Reactive Ion Etching (RIE) followed by Dopant Selective Reactive Ion Etching (DSRIE). The process may produce silicon carbide (SiC) diaphragms thinner than 10 microns. These thinner, more sensitive diaphragms may then be used to effectively resolve sub-psi pressures in jet engines, for example.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Publication Date: 2019-08-27
    Description: An active gas-gap heat switch may significantly reduce the time required to transition between the open and closed states, reduce the heat require to warm the getter, and reduce the heat that leaks from the getter to the switch body. A thermal interface at one end of the active gas-gap heat switch may include a plurality of fins. A getter assembly may be hermetically attached to the thermal interface and a containment tube may surround and house the plurality of fins.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-08-27
    Description: A vibration ring is provided to remove vibratory energy from a machine driveline. The vibration ring includes a compression cage configured to generate vibratory excitation within a material. The material is configured to generate an electric charge dissipated through or harvested by an electric circuit.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Publication Date: 2019-08-27
    Description: Disclosed are methods of building Z-graded radiation shielding and covers. In one aspect. the method includes: providing a substrate surface having about medium Z-grade; plasma spraying a first metal having higher Z-grade than the substrate surface; and infusing a polymer layer to form a laminate. In another aspect, the method includes electro/electroless plating a first metal having higher Z-grade than the substrate surface. In other aspects, the invention provides methods of improving an existing electronics enclosure to build a Z-graded radiation shield by applying a temperature controller to at least part of the enclosure and affixing at least one layer of a first metal having higher Z-grade than the enclosure.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2019-08-27
    Description: A thermomechanical memory/logic device is disclosed. In embodiments, the thermomechanical device includes a first thermally controlled terminal (e.g., hot terminal); a second thermally controlled terminal (e.g., cool terminal/base); a stem or other structure that can be thermally expanded connected to the cool terminal; and a thermal conductive head coupled to the stem. The head can exchange heat with the hot terminal. The stem and head are between the first thermally controlled terminal and the second thermally controlled terminal, wherein the stem expands or contracts in response to heat absorbed or given off by the thermal conductive head, causing the head to move towards the first thermally controlled terminal or towards the second thermally controlled terminal until a stable state is reached. For example, bistable thermal states can be used to implement logic states (e.g., ZERO or ONE states).
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Publication Date: 2019-07-12
    Description: We describe analytical methods for the design of the discrete elements of ultralight lattice structures. This modular, building block strategy allows for relatively simple element manufacturing, as well as relatively simple robotic assembly of low mass density structures on orbit, with potential for disassembly and reassembly into highly varying and large structures. This method also results in a structure that is easily navigable by relatively small mobile robots. The geometry of the cell can allow for high packing efficiency to minimize wasted payload volume while maximizing structural performance and constructability. We describe the effect of geometry choices on the final system mechanical properties, manufacturability of the components, and automated robotic constructability of a final system. Geometry choices considered include building block complexity, symmetry of the unit cell, and effects of vertex, edge, and face connectivity of the unit cell. Mechanical properties considered include strength scaling, modulus scaling, and structural performance of the joint, including proof load, shear load, mass, and loading area; as well as validation and verification opportunities. Manufacturability metrics include cost and time, manufacturing method (COTS versus custom), and tolerances required. Automated constructability metrics include local effects of loads imparted to the structure by the robot and assembly complexity, encompassing the ability of the robot to clamp and number of placement motions needed for assembly.
    Keywords: Mechanical Engineering
    Type: ARC-E-DAA-TN59962
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Publication Date: 2019-07-12
    Description: The initial objective of this study was to evaluate the effect of an extended delay time between preweld cleaning and the completion of a self-reacting friction stir welding (SRFSW) process on the resulting quality of various thickness panels of AA2219-T87. The current NASA standard specifies no more than a 48 hour delay between preweld cleaning and actual welding. The concern is whether increasing the cleaning delay time results in development of the residual oxide defect (ROD) in SRFSW. This concern emanates from the possibility of increased time correlating with increased oxide layer thickness on the faying surfaces. Oxide content on the faying surfaces has been reported to correlate with the occurrence of the ROD which reduces mechanical properties. When the SRFSW process was first adopted by the NASA Marshall Space Flight Center (MSFC), unexpected low tensile values that resulted were attributed to oxides within the weld that appeared to follow the former faying surface contours. Mitigation of the ROD was achieved through a combination of modifications to the processing parameters, tool designs, and incorporation of a weld seam offset. Two operations are involved in preweld cleaning: the first is removal of oil and grease, and the second is removal of surface oxides. In arc welding, improper cleaning of the faying surfaces of aluminum welded joints can increase the sensitivity toward development of defects. As the aluminum is locally melted, these contaminants contribute toward the development of porosity, inclusions, entrapped oxides, and other discontinuities which can degrade the strength of the weld joint. For weldment of large structures, the weld joint is typically cleaned, fit-up, and tack welded prior to the final full penetration welding pass. Because of the stringent joint fit-up requirements for mismatch and peaking for launch vehicle structures, the joint fit-up can sometimes contribute to lengthy delays between cleaning and tack welding, especially for circumferential weld joints on large diameter components. When the conventional friction stir welding (CFSW) process was introduced at the NASA MSFC, there was no procedure for cleaning prior to the solid-state joining process. As the process expanded to include SRFSW, preparation of the faying, crown, and root surfaces were implemented to overcome the ROD. Although the solid-state process is not expected to reach temperatures high enough for dissociation of the native oxide layer, concern remained regarding the redeposition of the native oxide layer within the stir zone. NASA has previously established the allowable time at 48 hours between preweld cleaning and a SRFSW process. The effect of potential 2 contamination resulting from an extended delay to 188 hours was subsequently evaluated for SRFSWs using tensile testing and metallographic imaging. Tensile specimens were tested at room temperature (RT), and at cryogenic conditions of liquid nitrogen (LN2) and liquid hydrogen. No detrimental effect on weld quality, as determined by weld strength, was reported for cleaning delays of 48, 120, 168, 240 or 288 hours. While no trends were established in this study, which extended the delay from 48 to 188 hours, there were a few outliers in terms of ultimate tensile strength (UTS). According to M. Fisher's 2014 Boeing Company Memo no. EYBF-MAF-14-029, all outliers were above the minimum acceptance criteria, but out of family with respect to the average values. As the robustness and reliability of any process ultimately depends on the average values as well as the outliers, an understanding of the cause of these outliers will ultimately improve the process. This report examines those outliers and their possible causes.
    Keywords: Mechanical Engineering
    Type: NASA/TM-2018-219863 , M18-6889 , M-1467
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-12
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: KSC-E-DAA-TN58160
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-12
    Description: Pathway Student Showcase - Environmental Control and Life Support System for Orion Ground and Flight Application Software Team
    Keywords: Mechanical Engineering
    Type: KSC-E-DAA-TN58151
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-12
    Description: This Technical Memorandum explains the friction stir welding process in terms of two basic concepts: the concentration of deformation in a shear surface enveloping the tool and the composition of the overall plastic flow field around the tool from simple flow field components. It is demonstrated how weld structure may be understood and torque, drag, and lateral tool forces may be estimated using these concepts. Some discrepancies between computations and accompanying empirical data are discussed in the text. This work is intended to be helpful to engineers in diagnosing problems and advancing technology.
    Keywords: Mechanical Engineering
    Type: NASA/TM-2018-219854 , M-1456
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: MSFC-E-DAA-TN63555 , IEEE International Conference on Wireless for Space and Extreme Environments; Dec 11, 2018 - Dec 13, 2018; Huntsville, AL; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Publication Date: 2019-07-13
    Description: The electrostatic levitation (ESL) laboratory at NASA's Marshall Space Flight Center (MSFC) is a national resource for researchers developing advanced materials for new technologies. Electrostatic levitation minimizes gravitational effects and allows materials to be studied without contact with a container or data-gathering instrumentation.
    Keywords: Mechanical Engineering
    Type: M18-7037 , Materials Science & Technology 2018; Oct 14, 2018 - Oct 18, 2018; Columbus, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Publication Date: 2019-07-13
    Description: For several years, NASA Glenn Research Center and the U.S. Army Research Laboratory have been investigating hybrid (compositesteel) gear technology for use in vertical lift drive systems. The hybrid gear concept replaces the structural portion of a gear between the shaft and the gear rim with a lightweight carbon fiber composite, in an effort to reduce the overall weight of a gear and increase the drive system power density. An overview of the concept of the hybrid gear design is described in Ref. 1, 2, and 3. The research presented in these references includes both small-scale and large-scale hybrid gear concepts all of which have a constant composite thickness throughout. The design described in this paper is of a variable thickness, such that the composite is thickest at the inner diameter and this thickness is gradually reduced toward the outer diameter. The resulting stair stepped design stems from dropping plies of the braided carbon fiber composite fabric gradually with increased radius. Additionally, the interlock pattern at the inner metallic adapter was adjusted slightly from previous designs to obtain a better stress distribution on the inner metallic adapter. The manufactured variable thickness web was tested both in static torsion tests and operationally in a relevant gearbox environment. The results of these experiments will be presented and compared to a baseline steel configuration.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN56366 , Annual Forum & Technology Display of the Vertical Flight Society; May 14, 2018 - May 17, 2018; Phoenix, AZ; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Publication Date: 2019-07-13
    Description: Over the last few decades, advances in high-performance computing, new materials characterization methods, and, more recently, an emphasis on integrated computational materials engineering (ICME) and additive manufacturing have been a catalyst for multiscale modeling and simulation-based design of materials and structures in the aerospace industry. While these advances have driven significant progress in the development of aerospace components and systems, that progress has been limited by persistent technology and infrastructure challenges that must be overcome to realize the full potential of integrated materials and systems design and simulation modeling throughout the supply chain. As a result, NASA's Transformational Tools and Technology (TTT) Project sponsored a study (performed by a team led by Pratt & Whitney) to define the potential 25-year future state required for integrated multiscale modeling of materials and systems (e.g., load-bearing structures) to accelerate the pace and reduce the expense of innovation in future aerospace and aeronautical systems. This talk will describe the findings of this 2040 Vision study (e.g., the 2040 vision state; the required interdependent core technical work areas, Key Element (KE); associated critical gaps and actions to close those gaps; and major recommendations). This roadmap is a community consensus document and is a result of over 450 professionals input obtain via: i) four society workshops (AIAA, NAFEMS, and two TMS), ii) community-wide survey, and iii) the establishment of 9 expert panels (one per key element) consisting on average 10 non-team members from academia, government and industry to review, update content, and prioritize gaps and actions. It is NASA's hope and desire that this roadmap provides the strategic guidance to both public and private research and development decision makers to make the proposed 2040 vision state a reality and thereby provide a significant advancement in the United States global competitiveness.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN56229 , AeroMat 2018; May 07, 2018 - May 09, 2018; Orlando, FL; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Publication Date: 2019-07-13
    Description: A variety of mission concepts have been studied by NASA and the U. S. Department of Energy that would utilize low power Radioisotope Power Systems (RPS) for probes, landers rovers, and repeaters. These missions would contain science instruments distributed across planetary surfaces or near objects of interest where solar flux is insufficient for using solar cells. Landers could be used to provide data like radiation, temperature, pressure, seismic activity, and other surface measurements for planetary science and to inform future mission planners. The studies proposed using fractional versions of the General Purpose Heat Source (GPHS) or multiple Light Weight Radioisotope Heater Units (LWRHU) to heat power conversion technologies for science instruments and communication. Dynamic power systems are capable of higher conversion efficiencies, which could enable equal power using less fuel or more power using equal fuel, when compared to less efficient static power conversion technologies. Providing spacecraft with more power would decrease duty cycling of basic functions and, therefore, increase the quality and abundance of science data. Low power Stirling convertors are being developed at NASA Glenn Research Center (GRC) to provide future micro spacecraft with electrical power by converting heat from one or more LWRHUs. An initial design converts multiple watts of heat to one watt of electrical power output using a Stirling convertor. Development of the concept includes maturation of convertor and controller designs, performance evaluation of an evacuated metal foil insulation, and development of system interfaces. Demonstration of the convertor is planned and represents a new class of RPS with power levels an order of magnitude lower than previous practical designs.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN57599 , International Energy Conversion Engineering Conference; Jul 09, 2018 - Jul 11, 2018; Cincinnati, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Publication Date: 2019-07-13
    Description: The Advanced eLectrical Bus (ALBus) project is a technology demonstration mission of a 3U CubeSat with an advanced, digitally controlled electrical power system capability and the novel use of Shape Memory Alloy (SMA) technology for reliable solar array (SA) deployable mechanisms. The ALBus CubeSat deploys four SAs in addition to the body-mounted arrays on each side of the CubeSat. A goal of the mission is to utilize the SMAs being developed at the NASA Glenn Research Center to deploy these SAs. The use of SMAs allows for the ability to test and reset the flight deployment mechanism prior to flight, which reduces the risk of in orbit deployment failures common to CubeSats. As a result, an SMA-driven Retention and Release (R&R) mechanism and an SMA-driven hinge were designed, developed, and integrated for flight. This paper summarizes the development of these mechanisms, types and functionalities of the SMAs used, as well as the lessons learned throughout the process.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN50835 , Aerospace Mechanisms Symposium; May 16, 2018 - May 18, 2018; Cleveland, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Publication Date: 2019-07-13
    Description: Most failures in MLCCs are caused by cracking that create shorts between opposite electrodes of the parts. A use of manual soldering makes this problem especially serious for space industry. Experience shows that different lots of ceramic capacitors might have different susceptibility to cracking under manual soldering conditions. This simulates a search of techniques that would allow revealing capacitors that are most robust to soldering-induced stresses. Currently, base metal electrode (BME) capacitors are introduced to high-reliability applications as a replacement of precious metal electrode (PME) parts. Understanding the difference in the susceptibility to cracking between PME and BME capacitors would facilitate this process. This presentation gives a review of mechanical characteristics measured in-situ on MLCCs that includes flexural strength, Vickers hardness, indentation fracture toughness, and the board flex testing and compare characteristics of BME and PME capacitors. A history case related to cracking in PME capacitors that caused flight system malfunctions and mechanisms of failure are considered. Possible qualification tests that would allow evaluation of the resistance of MLCCs to manual soldering are suggested and perspectives related to introduction of BME capacitors discussed.
    Keywords: Mechanical Engineering
    Type: GSFC-E-DAA-TN65862 , GSFC-E-DAA-TN53861 , 2018 CMSE Components for Military & Space Electronics Training & Exhibition; May 07, 2018 - May 10, 2018; Los Angeles, CA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production and use of aerospace mechanisms. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms.
    Keywords: Mechanical Engineering
    Type: NASA/CP-2018-219887 , GRC-E-DAA-TN51241 , E-19501 , Aerospace Mechanism Symposium; May 16, 2018 - May 18, 2018; Cleveland, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-08-26
    Description: Some embodiments of the invention include a boom deployment system. The boom deployment system, for example, may include a housing, a spool, a first boom, and a second boom. The spool may be disposed within the housing and configured to rotate around an axis that is fixed relative to the housing. The first boom and/or the second boom may have a cylindrical shape in a deployed configuration, a flattened shape in a stowed configuration, and a slit that extends along the longitudinal length of the boom in the deployed configuration. The first boom and/or the second boom may be stowed in the stowed configuration flattened and wrapped around the spool. The first boom and/or the second boom may transition from the stowed configuration to the deployed configuration as the spool rotates around the axis.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2019-08-26
    Description: Systems and methods in accordance with embodiments of the invention implement additive manufacturing techniques that employ different sets of deposition characteristics and/or material formation characteristics during the additive manufacture of an object so as to strategically build up the object. In many embodiments, material used to build up an object is deposited at different deposition rates during the additive manufacture of the object, and the object is thereby strategically built up. In one embodiment, a method of additively manufacturing an object includes: depositing material onto a surface at a first deposition rate so as to define a first region of the object to be additively manufactured; and depositing material onto a surface at a second deposition rate so as to define a second region of the object to be additively manufactured; where the second deposition rate is different from the first deposition rate.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Publication Date: 2019-08-26
    Description: A silicon alignment pin is used to align successive layer of component made in semiconductor chips and/or metallic components to make easier the assembly of devices having a layered structure. The pin is made as a compressible structure which can be squeezed to reduce its outer diameter, have one end fit into a corresponding alignment pocket or cavity defined in a layer of material to be assembled into a layered structure, and then allowed to expand to produce an interference fit with the cavity. The other end can then be inserted into a corresponding cavity defined in a surface of a second layer of material that mates with the first layer. The two layers are in registry when the pin is mated to both. Multiple layers can be assembled to create a multilayer structure. Examples of such devices are presented.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Publication Date: 2019-12-04
    Description: A promising candidate for deployable composite structures is the two-shelled Collapsible Tubular Mast (CTM) boom, which is to be employed on future solar sail and interplanetary small satellite platforms by the National Aeronautics and Space Administration (NASA). This is due to its two omega-shaped shells forming a closed-section which yields large stiffnesses that allowed for high dimensional stability. An inextensional analytical model describing the bending deformation mechanics of CTM booms was used to determine how design variables induce bistability, or the existence of two strain energy wells. Bistable booms were favorable due to low strain energy requirements for the coiled state and had more controllable deployment when compared to monostable booms. The effects of varying lamina material, laminate layup, and shell arc geometries between different inner and outer shell segments on the second strain energy well and stiffness properties were determined for cross-sections formed by circular segments. The full design space for two-shelled composite CTM booms was explored to evaluate the validity of the simple analytical model developed. Optimal CTM boom designs were manufactured and experimentally characterized for comparisons against model results. The model under-predicted the second stable coiled diameter of the complete two-shelled booms by 27-33% and as low as 3-8% for the individual shells wrapped alone.
    Keywords: Mechanical Engineering
    Type: NF1676L-30217 , International Conference on Advanced Lightweight Structures and Reflector Antennas; Sep 19, 2018 - Sep 21, 2018; Tbilisi, GA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-02-10
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-01-27
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-01-27
    Description: Polynitrogens have the potential for ultrahigh-performing explosives or propellants because singly or doubly bonded polynitrogens can decompose to triply bonded dinitrogen (N2) with an extraordinarily large energy release. The large energy content and relatively low activation energy toward decomposition makes the synthesis of a stable polynitrogen allotrope an extraordinary challenge. Many elements exist in different forms (allotropes)—for example, carbon can exist as graphite, diamond, buckyballs, or graphene. However, no stable neutral allotropes are known for nitrogen, and only two stable homonuclear polynitrogen ions had been isolated until now—namely, the N3− anion (1) and the N5+ cation (2). On page 374 of this issue, Zhang et al. (3) report the synthesis and characterization of the first stable salt of the cyclo-N5− anion, only the third stable homonuclear polynitrogen ion ever isolated. Author: Karl O. Christe
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Publication Date: 2019-07-12
    Description: No abstract available
    Keywords: Mechanical Engineering
    Type: JSC-CN-39577
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Publication Date: 2019-07-12
    Description: Embodiments of isolators, such as three parameter isolators, including a main spring linear guide system are provided. In one embodiment, the isolator includes first and second opposing end portions, a main spring mechanically coupled between the first and second end portions, and a linear guide system extending from the first end portion, across the main spring, and toward the second end portion. The linear guide system expands and contracts in conjunction with deflection of the main spring along the working axis, while restricting displacement and rotation of the main spring along first and second axes orthogonal to the working axis.
    Keywords: Mechanical Engineering
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-12
    Description: NASA is working in junction with another company on the Electric Turbo Pump. Analysis of the impeller, including the blades, volute housing, and associated components, will take place in ANSYS. Contours of the deformed and stress were recorded to assess the parts. Campbell diagrams will be considered as mentioned to find the operating regions of the impeller and volute housing, more specifically what speed is ideal to ensure that the impeller does not begin to vibrate at a frequency that will break it. More than one material will be examined as per request by the designer to determine which material is more cost efficient, easy to machine, and can withstand the stress values that will be placed on it.
    Keywords: Mechanical Engineering
    Type: M17-6447
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Publication Date: 2019-07-12
    Description: Valves are used to regulate the flow of fluids through systems. This rotary valve's main purpose is to fill, pressurize, empty, and vent three smaller tanks with the supply of one larger tank. Many different designs are being taken into consideration, which are each at different stages of development. The furthest along uses three ball valves on a common shaft to open and close their respective ports as the shaft completes one full rotation or cycle. We were tasked with advancing this design to its first test as a plastic model for flow verification, as well as sizing and ordering the necessary O-rings and fasteners. A motor will also be sized to satisfy the torque requirements, and will then be programmed using a Raspberry Pi to rotate the shaft at the calculated speed and dwelling times needed to fill each tank equally. In addition, we have also been advancing designs that use a camshaft and poppets. These are earlier on in their development, currently being sized to replicate the expected flow patterns of the rotary ball valve. Expected outcomes of this valve include bi-directionality, successful sealing under pressure, and accurate cycling.
    Keywords: Mechanical Engineering
    Type: M17-6448
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...