Direct Laser Fabrication of a Gas Turbine Engine Component - Microstructure and Properties - Part I

This paper presents the development of a new technique for the production of abrasive turbine blade tips by direct laser processing. This superalloy cermet component is an integral part of the low pressure turbine sealing system in a demonstrator engine. Direct laser fabrication of this component fiom a bed a loose powder results in significant cost savings and improved performance over the currently employed production technique. The technology has been demonstrated by fabricating a prototype lot of 100 blade tips, which will be subjected to an engine test. This is the first instance of a direct fabrication method applied to the production of functional engine hardware. This research was funded by the United States Air Force contract F33615-94- C-2424 titled "Affordable Turbine Blade Tips".Mechanical Engineerin

NASA's Space Launch System Progress Report

Exploration beyond Earth will be an enduring legacy for future generations, confirming America's commitment to explore, learn, and progress. NASA's Space Launch System (SLS) Program, managed at the Marshall Space Flight Center, is responsible for designing and developing the first exploration-class rocket since the Apollo Program's Saturn V that sent Americans to the Moon. The SLS offers a flexible design that may be configured for the MultiPurpose Crew Vehicle and associated equipment, or may be outfitted with a payload fairing that will accommodate flagship science instruments and a variety of high-priority experiments. Both options support a national capability that will pay dividends for future generations. Building on legacy systems, facilities, and expertise, the SLS will have an initial lift capability of 70 metric tons (mT) and will be evolvable to 130 mT. While commercial launch vehicle providers service the International Space Station market, this capability will surpass all vehicles, past and present, providing the means to do entirely new missions, such as human exploration of asteroids and Mars. With its superior lift capability, the SLS can expand the interplanetary highway to many possible destinations, conducting revolutionary missions that will change the way we view ourselves, our planet and its place in the cosmos. To perform missions such as these, the SLS will be the largest launch vehicle ever built. It is being designed for safety and affordability - to sustain our journey into the space age. Current plans include launching the first flight, without crew, later this decade, with crewed flights beginning early next decade. Development work now in progress is based on heritage space systems and working knowledge, allowing for a relatively quick start and for maturing the SLS rocket as future technologies become available. Together, NASA and the U.S. aerospace industry are partnering to develop this one-of-a-kind asset. Many of NASA's space centers across the country will provide their unique expertise to the Space Launch System endeavor. Unique infrastructure to be used includes the Michoud Assembly Facility for tank manufacturing, Stennis Space Center for engine testing, and Kennedy Space Center for processing and launch. As this panel will discuss, the SLS team is dedicated to doing things differently-from applying lean oversight/insight models to smartly using legacy hardware and existing facilities. Building on the foundation laid by over 50 years of human and scientific space flight--and on the lessons learned from the Apollo, Space Shuttle, and Constellation Programs-the SLS team has delivered both technical trade studies and business case analyses to ensure that the SLS architecture will be safe, affordable, reliable, and sustainable

NASA's Space Launch System Progress Report

Exploration beyond Earth orbit will be an enduring legacy for future generations, as it provides a platform for science and exploration that will define new knowledge and redefine known boundaries. NASA s Space Launch System (SLS) Program, managed at the Marshall Space Flight Center, is responsible for designing and developing the first exploration-class rocket since the Apollo Program s Saturn V that sent Americans to the Moon in the 1960s and 1970s. The SLS offers a flexible design that may be configured for the Orion Multi-Purpose Crew Vehicle with associated life-support equipment and provisions for long journeys or may be outfitted with a payload fairing that will accommodate flagship science instruments and a variety of high-priority experiments. Building on legacy systems, facilities, and expertise, the SLS will have an initial lift capability of 70 tonnes (t) in 2017 and will be evolvable to 130 t after 2021. While commercial launch vehicle providers service the International Space Station market, this capability will surpass all vehicles, past and present, providing the means to do entirely new missions, such as human exploration of Mars. Building on the foundation laid by over 50 years of human and scientific space flight and on the lessons learned from the Apollo, Space Shuttle, and Constellation Programs the SLS team is delivering both technical trade studies and business case analyses to ensure that the SLS architecture will be safe, affordable, reliable, and sustainable. This panel will address the planning and progress being made by NASA s SLS Program

RSRM Segment Train Derailment and Recovery

On May 2, 2007, a freight train carrying segments of the space shuttle's solid rocket boosters derailed in Myrtlewood, Alabama, after a rail trestle collapsed. The train was carrying Reusable Solid Rocket Motors (RSRM) 98 center and forward segments (STS-120) and RSRM 99 aft segments (STS-122). Initially, it was not known if the segments had been seriously damaged. Four segments dropped approximately 10 feet when the trestle collapsed and one of those four rolled off the track onto its side. The exit cones and the other four segments, not yet on the trestle, remained on solid ground. ATK and NASA immediately dispatched an investigation and recovery team to determine the safety of the situation and eventually the usability of the segments and exit cones for flight. Instrumentation on each segment provided invaluable data to determine the acceleration loads imparted into each loaded segment and exit cone. This paper details the incident, recovery plan and the team work that created a success story that ended with the safe launch of STS120 using the four center segments and the launch of STS122 using the Aft exit cones assemblies

Nanosat Intelligent Power System Development

NASA Goddard Space Flight Center is developing a class of satellites called nano-satellites. The technologies developed for these satellites will enable a class of constellation missions for the NASA Space Science Sun-Earth Connections theme and will be of great benefit to other NASA enterprises. A major challenge for these missions is meeting significant scientific- objectives with limited onboard and ground-based resources. Total spacecraft power is limited by the small satellite size. Additionally, it is highly desirable to minimize operational costs by limiting the ground support required to manage the constellation. This paper will describe how these challenges are met in the design of the nanosat power system. We will address the factors considered and tradeoffs made in deriving the nanosat power system architecture. We will discuss how incorporating onboard fault detection and correction capability yields a robust spacecraft power bus without the mass and volume penalties incurred from redundant systems and describe how power system efficiency is maximized throughout the mission duration

NASA's Space Launch System: Exploration Beyond Earth's Orbit

No abstract availabl

Angiosperm phylogeny: 17 genes, 640 taxa

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/1/ajb20704-sup-0010.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/2/ajb20704.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/3/ajb20704-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/4/ajb20704-sup-0016.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/5/ajb20704-sup-0017.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/6/ajb20704-sup-0021.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/7/ajb20704-sup-0003.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/8/ajb20704-sup-0002.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/9/ajb20704-sup-0011.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/10/ajb20704-sup-0019.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/11/ajb20704-sup-0015.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/12/ajb20704-sup-0006.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/13/ajb20704-sup-0020.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/14/ajb20704-sup-0013.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/15/ajb20704-sup-0004.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/16/ajb20704-sup-0012.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/17/ajb20704-sup-0005.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/18/ajb20704-sup-0018.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/19/ajb20704-sup-0009.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/20/ajb20704-sup-0014.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/21/ajb20704-sup-0007.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/22/ajb20704-sup-0008.pd

Angiosperm Phylogeny: 17 Genes, 640 Taxa

• Premise of the study : Recent analyses employing up to fi ve genes have provided numerous insights into angiosperm phylogeny, but many relationships have remained unresolved or poorly supported. In the hope of improving our understanding of angiosperm phylogeny, we expanded sampling of taxa and genes beyond previous analyses. • Methods : We conducted two primary analyses based on 640 species representing 330 families. The fi rst included 25 260 aligned base pairs (bp) from 17 genes (representing all three plant genomes, i.e., nucleus, plastid, and mitochondrion). The second included 19 846 aligned bp from 13 genes (representing only the nucleus and plastid). • Key results : Many important questions of deep-level relationships in the nonmonocot angiosperms have now been resolved with strong support. Amborellaceae, Nymphaeales, and Austrobaileyales are successive sisters to the remaining angiosperms ( Mesangiospermae ), which are resolved into Chloranthales + Magnoliidae as sister to Monocotyledoneae + [Ceratophyllaceae + Eudicotyledoneae ]. Eudicotyledoneae contains a basal grade subtending Gunneridae . Within Gunneridae , Gunnerales are sister to the remainder ( Pentapetalae ), which comprises (1) Superrosidae , consisting of Rosidae (including Vitaceae) and Saxifragales; and (2) Superasteridae , comprising Berberidopsidales, Santalales, Caryophyllales , Asteridae , and, based on this study, Dilleniaceae (although other recent analyses disagree with this placement). Within the major subclades of Pentapetalae , most deep-level relationships are resolved with strong support. • Conclusions : Our analyses confi rm that with large amounts of sequence data, most deep-level relationships within the angiosperms can be resolved. We anticipate that this well-resolved angiosperm tree will be of broad utility for many areas of biology, including physiology, ecology, paleobiology, and genomics

Molecular Antimicrobial Resistance Surveillance for Neisseria gonorrhoeae, Northern Territory, Australia

Emerging Infectious Disease's an open access journal in the public domain. All content is freely available without charge to the user or his/her institution.Neisseria gonorrhoeae antimicrobial resistance (AMR) is a globally recognized health threat; new strategies are needed to enhance AMR surveillance. The Northern Territory of Australia is unique in that 2 different first-line therapies, based primarily on geographic location, are used for gonorrhea treatment. We tested 1,629 N. gonorrhoeae nucleic acid amplification test-positive clinical samples, collected from regions where ceftriaxone plus azithromycin or amoxicillin plus azithromycin are recommended first-line treatments, by using 8 N. gonorrhoeae AMR PCR assays. We compared results with those from routine culture-based surveillance data. PCR data confirmed an absence of ceftriaxone resistance and a low level of azithromycin resistance (0.2%), and that penicillin resistance was <5% in amoxicillin plus azithromycin regions. Rates of ciprofloxacin resistance and penicillinase-producing N. gonorrhoeae were lower when molecular methods were used. Molecular methods to detect N. gonorrhoeae AMR can increase the evidence base for treatment guidelines, particularly in settings where culture-based surveillance is limited

Path-Breakers: How Does Women's Political Participation Respond to Electoral Success?

This paper analyzes the effect of a woman's electoral victory on women's subsequent political participation. Using the regression discontinuity afforded by close elections between women and men in India's state elections, we find that a woman winning office leads to a large and significant increase in the share of female candidates from major political parties in the subsequent election. This stems mainly from an increased probability that previous women candidates contest again, an important margin in India where a substantial number of incumbents do not contest re-election. There is no significant entry of new female candidates, no change in female or male voter turnout and no spillover effects to neighboring areas. Further analysis points to a reduction in party bias against women candidates as the main mechanism driving the observed increase in women's candidacy