Science.gov

Sample records for lecheras al inicio

  1. Asociación de la adherencia a la dieta mediterránea al inicio del embarazo y riesgo de gastrosquisis en la descendencia: un estudio de casos-controles

    PubMed Central

    Cánovas-Conesa, A.; Gomariz-Peñalver, V.; Sánchez-Sauco, M.F.; Vega, D.C. Jaimes; Ortega-García, J.A.; García, M.J. Aranda; Marín, J.L. Delgado; Ascanio, A. Trujillo; Hernández, F. López; Jimenez, J.I. Ruiz; de Paco Matallana, C.; Soldin, O.P.; Solís, M. Sánchez

    2016-01-01

    Resumen Objetivos El objetivo de este estudio fue estudiar la asociación de la adherencia a la dieta mediterránea materna al inicio del embarazo y el riesgo de gastrosquisis en la descendencia. Métodos Estudio de casos-control. 11 casos incidentes de gastrosquisis en la Región de Murcia de 2007 a 2012 y 34 controles concurrentes. Cuestionario validado de Frecuencia Alimentaria (CFA) sobre la dieta periconcepcional de 98 ítems realizado ‘cara a cara’ en el momento del diagnóstico. Factores confundidores: tabaquismo, expositión a cannabis/marihuana, edad materna y paterna, índice de masa corporal, ingresos económicos y nivel de estudios. Estudio descriptivo y regresión logística multivariable. Resultados Las madres de niños con gastrosquisis son más jóvenes (20,8 años; IC 95% 17,3–24,2) y su dieta tiene un menor aporte calórico, de grasas saturadas y monoinsaturadas y de proteínas que los controles. Odds Ratio (OR) en el modelo multivariable controlado por los factores confundidores: edad materna (años) 0,70 (IC95% 0,51–0,96); ácidos grasos monoinsaturados (oleico, g) 0,79 (IC95% 0,65–0,97) y consumo de vegetales (raciones/semana) 0,70 (IC95% 0,48–1,00). Conclusiones Una dieta materna rica en ácido oleico y productos vegetales podría contribuir a prevenir el riesgo de oclusión vascular de las arterias onfalomesentéricas, disminuyendo el riesgo de gastrosquisis. PMID:23833926

  2. Prevalencia y factores de riesgo para infecciones del tracto urinario de inicio en la comunidad causadas por Escherichia coli productor de betalactamasas de espectro extendido en Colombia

    PubMed Central

    Blanco, Victor M.; Maya, Juan J.; Correa, Adriana; Perenguez, Marcela; Muñoz, Juan S.; Motoa, Gabriel; Pallares, Christian J.; Rosso, Fernando; Matta, Lorena; Celis, Yamile; Garzon, Martha; Villegas, y María V.

    2016-01-01

    RESUMEN Introducción Las infecciones del tracto urinario (ITU) son frecuentes en la comunidad. Sin embargo, la información de aislamientos resistentes en este contexto es limitada en Latinoamérica. Este estudio tiene como objetivo determinar la prevalencia y los factores de riesgo asociados con ITU de inicio en la comunidad (ITU-IC) causadas por Escherichia coli productor de betalactamasas de espectro extendido (BLEE) en Colombia. Materiales y métodos Entre agosto y diciembre de 2011 se realizó un estudio de casos y controles en 3 instituciones de salud de tercer nivel en Colombia. Se invitó a participar a todos los pacientes admitidos a urgencias con diagnóstico probable de ITU-IC, y se les pidió una muestra de orina. En los aislamien-tos de E. coli se realizaron pruebas confirmatorias para BLEE, susceptibilidad antibiótica, caracterización molecular (PCR en tiempo real para genes bla, repetitive element palindromic PCR [rep-PCR], multilocus sequence typing [MLST] y factores de virulencia por PCR). Se obtuvo información clínica y epidemiológica, y posteriormente se realizó el análisis estadístico. Resultados De los 2.124 pacientes seleccionados, 629 tuvieron un urocultivo positivo, en 431 de estos se aisló E. coli, 54 fueron positivos para BLEE y 29 correspondieron a CTX-M-15. La mayoría de los aislamientos de E. coli productor de BLEE fueron sensibles a ertapenem, fosfomicina y amikacina. La ITU complicada se asoció fuertemente con infecciones por E. coli productor de BLEE (OR = 3,89; IC 95%: 1,10–13,89; p = 0,03). E. coli productor de CTX-M-15 mostró 10 electroferotipos diferentes; de estos, el 65% correspondieron al ST131. La mayoría de estos aislamientos tuvieron 8 de los 9 factores de virulencia analizados. Discusión E. coli portador del gen blaCTX-M-15 asociado al ST131 sigue siendo frecuente en Colombia. La presencia de ITU-IC complicada aumenta el riesgo de tener E. coli productor de BLEE, lo cual debe tenerse en cuenta para ofrecer

  3. Diagnosing ALS

    MedlinePlus

    ... do to #ChallengeALS About This Site Policies Site Map Pay tribute to those fighting ALS with a Community of Hope fund Start your own fundraising event & help create a world without ALS Join this nationwide movement by walking ...

  4. ALS Association

    MedlinePlus

    ... toward a world without ALS! Walk to Defeat ALS® Walk to Defeat ALS® draws people of all ... We need your help. I Will Advocate National ALS Registry The National ALS Registry is a congressionally ...

  5. Familial ALS

    PubMed Central

    Boylan, Kevin

    2015-01-01

    Synopsis Genes linked to ALS susceptibility are being identified at an increasing rate owing to advances in molecular genetic technology. Genetic mechanisms in ALS pathogenesis appear to exert major effects in ~10% of patients, but genetic factors at some level may be important components of disease risk in most ALS patients. Identification of gene variants associated with ALS has informed concepts of the pathogenesis of ALS, aided the identification of therapeutic targets, facilitated research to develop new ALS biomarkers, and supported the establishment of clinical diagnostic tests for ALS-linked genes. Translation of this knowledge to ALS therapy development is ongoing. PMID:26515623

  6. ALS - resources

    MedlinePlus

    Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association -- www.mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) ...

  7. Lou Gehrig's Disease (ALS)

    MedlinePlus

    ... for Educators Search English Español Lou Gehrig's Disease (ALS) KidsHealth / For Kids / Lou Gehrig's Disease (ALS) What's ... with ALS in the 1930s. What Happens in ALS? ALS damages motor neurons in the brain and ...

  8. All About ALS

    MedlinePlus

    ... Subscribe August 2015 Print this issue All About ALS Understanding a Devastating Disorder En español Send us ... Sports Concussions Wise Choices How Can I Help ALS Research? If you have ALS, join the National ...

  9. Genetic Testing for ALS

    MedlinePlus

    ... In Your Community Advocate Get Involved Donate Familial Amyotrophic Lateral Sclerosis (FALS) and Genetic Testing By Deborah Hartzfeld, MS, CGC, Certified Genetic Counselor Familial ALS Most of the time ALS is not inherited. ...

  10. Initial Symptoms of ALS

    MedlinePlus

    ... Chapters Certified Centers and Clinics Support Groups About ALS About Us Our Research In Your Community Advocate ... Diagnosis En español Symptoms The initial symptoms of ALS can be quite varied in different people. One ...

  11. Amyotrophic lateral sclerosis (ALS)

    MedlinePlus

    Lou Gehrig disease; ALS; Upper and lower motor neuron disease; Motor neuron disease ... One out of 10 cases of ALS is due to a genetic defect. The cause is unknown in most other cases. In ALS, motor nerve cells (neurons) waste away ...

  12. Abu al-Layth al-Libi

    DTIC Science & Technology

    2015-02-01

    2015 4. TITLE AND SUBTITLE Abu al-Layth al-Libi 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT NUMBER...5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) U.S. Military Academy,Combating Terrorism Center,West...Point,NY,10996 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM( S ) 11

  13. Al Basrah, Iraq

    NASA Image and Video Library

    2017-12-08

    Al Basrah, Iraq Sensor: L7 ETM+ Acquisition Date: April 4, 2003 Path/Row: 166/39 Lat/Long: 30.486/47.811 Smoke drifts south in this image of Al Basrah, located in southeastern Iraq. The green circles from the center to the left of the image represent irrigated crops.

  14. Rub al Khali, Arabia

    NASA Image and Video Library

    2008-08-08

    NASA Terra spacecraft shows the Rub al Khali, one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula; it includes parts of Oman, United Arab Emirates, and Yemen.

  15. Ag-Al-Ca

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/97.etType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Ag-Al-Ca' with the content:

  16. ALS superbend magnet performance

    SciTech Connect

    Marks, Steve; Zbasnik, John; Byrne, Warren

    2001-12-10

    The Lawrence Berkeley National Laboratory has been engaged in the design, construction and testing of four superconducting dipoles (Superbends) that are installed in three arcs of the Advanced Light Source (ALS), with the fourth magnet as a spare. This represents a major upgrade to the ALS providing an enhanced flux and brightness at photon energies above 10 keV. In preparation for installation, an extensive set of tests and measurements have been conducted to characterize the magnetic and cryogenic performance of the Superbends and to fiducialize them for accurate placement in the ALS storage ring. The magnets are currently installed, andmore » the storage ring is undergoing final commissioning. This paper will present the results of magnetic and cryogenic testing.« less

  17. Statins: Do They Cause ALS?

    MedlinePlus

    ... they cause ALS? Do statins cause amyotrophic lateral sclerosis (ALS)? Answers from Francisco Lopez-Jimenez, M.D. ... Sorensen HT, et al. Statins and amyotrophic lateral sclerosis: The level of evidence for an association. Journal ...

  18. Fosetyl-al

    Integrated Risk Information System (IRIS)

    Integrated Risk Information System ( IRIS ) Chemical Assessment Summary U.S . Environmental Protection Agency National Center for Environmental Assessment This IRIS Summary has been removed from the IRIS database and is available for historical reference purposes . ( July 2016 ) Fosetyl - al ; CASRN

  19. Al Jazirah, Sudan

    NASA Image and Video Library

    2008-05-09

    Al Jazirah also Gezira is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. This image was acquired December 25, 2006 by NASA Terra spacecraft.

  20. Al Jazirah, Sudan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

    The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  1. Al Qaeda as a System

    DTIC Science & Technology

    2006-03-15

    violence. Those organic essentials are money, weapons, false documents, and sanctuaries . Al Qaeda has no population to tax for the purpose of...take sanctuary in numerous countries. To meet the basic needs for themselves as individuals and for the organization, Al Qaeda cells use host states...either as welcome guests or parasites. As welcome guests, Al Qaeda members take sanctuary in sponsor states. Sponsor states provide Al Qaeda with

  2. 76 FR 35938 - The Designation of Othman al-Ghamdi Also Known as Al Umairah al-Ghamdi, Also Known as Uthman al...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... as Uthman Ahmad Uthman al-Ghamdi, Also Known as Othman Ahmed Othman al-Omirah as a Specially... Uthman al-Ghamidi, also known as Uthman Ahmad Uthman al-Ghamdi, also known as Othman Ahmed Othman al...

  3. Friction welding of Al-Al, Al-steel, and steel-steel samples

    NASA Astrophysics Data System (ADS)

    Sahin, A. Z.; Yilbas, B. S.; Al-Garni, A. Z.

    1996-02-01

    Friction welding of Al- Al, Al- steel, and steel- steel studs is compared. Transient heat generation and temperature rise during the welding process were modeled. Tensile tests and microhardness measurements across the weld zone were carried out. The metallurgical changes in the heat- affected zone were examined by SEM. Temperature rise at the interface plane was computed and related to weld properties. The affecting parameters on weld quality were identified by statistical analysis. Results show that interaction of weld parameters significantly affect yield, tensile, and breaking strength, and the heat- affected zone on the Al side is wider for Al-steel welds.

  4. Morton et al. Reply

    NASA Technical Reports Server (NTRS)

    Morton, Douglas C.; Nagol, Jyoteshwar; Carabajal, Claudia C.; Rosette, Jacqueline; Palace, Michael; Cook, Bruce D.; Vermote, Eric F.; Harding, David J.; North, Peter R. J.

    2016-01-01

    Multiple mechanisms could lead to up-regulation of dry-season photosynthesis in Amazon forests, including canopy phenology and illumination geometry. We specifically tested two mechanisms for phenology-driven changes in Amazon forests during dry-season months, and the combined evidence from passive optical and lidar satellite data was incompatible with large net changes in canopy leaf area or leaf reflectance suggested by previous studies. We therefore hypothesized that seasonal changes in the fraction of sunlit and shaded canopies, one aspect of bidirectional reflectance effects in Moderate Resolution Imaging Spectroradiometer (MODIS) data, could alter light availability for dry-season photosynthesis and the photosynthetic capacity of Amazon forests without large net changes in canopy composition. Subsequent work supports the hypothesis that seasonal changes in illumination geometry and diffuse light regulate light saturation in Amazon forests. These studies clarify the physical mechanisms that govern light availability in Amazon forests from seasonal variability in direct and diffuse illumination. Previously, in the debate over light limitation of Amazon forest productivity, seasonal changes in the distribution of light within complex Amazon forest canopies were confounded with dry-season increases in total incoming photosynthetically active radiation. In the accompanying Comment, Saleska et al. do not fully account for this confounding effect of forest structure on photosynthetic capacity.

  5. 27Al MQMAS of the δ-Al 13-Keggin

    DOE PAGES

    Pilgrim, C. D.; Callahan, J. R.; Colla, C. A.; ...

    2017-01-20

    Here, one-dimensional 27Al, 23Na Magic-Angle-Spinning (MAS) NMR and 27Al Multiple-Quantum Magic-Angle-Spinning NMR (MQMAS) measurements are reported for the δ-isomer of the Al 13 Keggin structure at high spinning speed and 14.1 T field. Values for the CQ and η parameters are on the same scale as those seen in other isomers of the Al 13 structure. Density functional theory (DFT) calculations are performed for comparison to the experimental fits using the B3PW91/6-31+G* and PBE0/6-31+G* levels of theory, with the Polarizable Continuum Model (PCM).

  6. Alexandria (Al Iskandariya), Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Alexandria was taken by astronauts on board the International Space Station in December 2000 using an Electronic Still Camera. A wider-angle view (STS088-739-90) taken from the Space Shuttle in December 1998 is available for context. Alexandria (Al Iskandariya) occupies a T-shaped peninsula and strip of land separating the Mediterranean from Lake Mariout. Originally the town was built upon a mole (stone breakwater) called Heptastadium, which joined the island of Pharos (see referenced website, below) to the mainland. Since then sedimentary deposits have widened the mole. Since 1905, when the 370,000 Alexandrians lived in an area of about 4 sq km between the two harbors, the city (population 4 million; see referenced website, below) has grown beyond its medieval walls and now occupies an area of about 300 sq km. The Mahmudiya Canal, connecting Alexandria with the Nile, runs to the south of the city and, by a series of locks, enters the harbor of the principal port of Egypt (note ships). The reddish and ochre polygons west of Lake Mariout are salt-evaporation, chemical-storage, and water-treatment ponds within the coastal lagoon. Reference Youssef Halim and Fatma Abou Shouk, 2000, Human impacts on Alexandria's marine environment: UNESCO, Coastal Regions and Small Islands Unit (CSI), Coastal Management Sourcebooks 2 (accessed December 20, 2000) Additional photographs taken by astronauts can be viewed at NASA-JSC's Gateway to Astronaut Photography of Earth. Image ISS001-ESC-5025 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  7. Interfacial reactions and oxidation behavior of Al 2O 3 and Al 2O 3/Al coatings on an orthorhombic Ti 2AlNb alloy

    NASA Astrophysics Data System (ADS)

    Li, H. Q.; Wang, Q. M.; Gong, J.; Sun, C.

    2011-02-01

    The uniform and dense Al2O3 and Al2O3/Al coatings were deposited on an orthorhombic Ti2AlNb alloy by filtered arc ion plating. The interfacial reactions of the Al2O3/Ti2AlNb and Al2O3/Al/Ti2AlNb specimens after vacuum annealing at 750 °C were studied. In the Al2O3/Ti2AlNb specimens, the Al2O3 coating decomposed significantly due to reaction between the Al2O3 coating and the O-Ti2AlNb substrate. In the Al2O3/Al/Ti2AlNb specimens, a γ-TiAl layer and an Nb-rich zone came into being by interdiffusion between the Al layer and the O-Ti2AlNb substrate. The γ-TiAl layer is chemically compatible with Al2O3, with no decomposition of Al2O3 being detected. No internal oxidation or oxygen and nitrogen dissolution zone was observed in the O-Ti2AlNb alloy. The Al2O3/Al/Ti2AlNb specimens exhibited excellent oxidation resistance at 750 °C.

  8. Interfacial characterization of Al-Al thermocompression bonds

    SciTech Connect

    Malik, N., E-mail: nishantmalik1987@gmail.com; SINTEF ICT, Department of Microsystems and Nanotechnology, P.O. Box 124 Blindern, N-0314 Oslo; Carvalho, P. A.

    2016-05-28

    Interfaces formed by Al-Al thermocompression bonding were studied by the transmission electron microscopy. Si wafer pairs having patterned bonding frames were bonded using Al films deposited on Si or SiO{sub 2} as intermediate bonding media. A bond force of 36 or 60 kN at bonding temperatures ranging from 400–550 °C was applied for a duration of 60 min. Differences in the bonded interfaces of 200 μm wide sealing frames were investigated. It was observed that the interface had voids for bonding with 36 kN at 400 °C for Al deposited both on Si and on SiO{sub 2}. However, the dicing yield was 33% for Al onmore » Si and 98% for Al on SiO{sub 2}, attesting for the higher quality of the latter bonds. Both a bond force of 60 kN applied at 400 °C and a bond force of 36 kN applied at 550 °C resulted in completely bonded frames with dicing yields of, respectively, 100% and 96%. A high density of long dislocations in the Al grains was observed for the 60 kN case, while the higher temperature resulted in grain boundary rotation away from the original Al-Al interface towards more stable configurations. Possible bonding mechanisms and reasons for the large difference in bonding quality of the Al films deposited on Si or SiO{sub 2} are discussed.« less

  9. Interfacial characterization of Al-Al thermocompression bonds

    SciTech Connect

    Malik, N.; Carvalho, P. A.; Poppe, E.; Finstad, T. G.

    2016-05-28

    Interfaces formed by Al-Al thermocompression bonding were studied by the transmission electron microscopy. Si wafer pairs having patterned bonding frames were bonded using Al films deposited on Si or SiO{sub 2} as intermediate bonding media. A bond force of 36 or 60 kN at bonding temperatures ranging from 400–550 °C was applied for a duration of 60 min. Differences in the bonded interfaces of 200 μm wide sealing frames were investigated. It was observed that the interface had voids for bonding with 36 kN at 400 °C for Al deposited both on Si and on SiO{sub 2}. However, the dicing yield was 33% for Al on Si and 98% for Al on SiO{sub 2}, attesting for the higher quality of the latter bonds. Both a bond force of 60 kN applied at 400 °C and a bond force of 36 kN applied at 550 °C resulted in completely bonded frames with dicing yields of, respectively, 100% and 96%. A high density of long dislocations in the Al grains was observed for the 60 kN case, while the higher temperature resulted in grain boundary rotation away from the original Al-Al interface towards more stable configurations. Possible bonding mechanisms and reasons for the large difference in bonding quality of the Al films deposited on Si or SiO{sub 2} are discussed.

  10. Thermal Modeling of Al-Al and Al-Steel Friction Stir Spot Welding

    NASA Astrophysics Data System (ADS)

    Jedrasiak, P.; Shercliff, H. R.; Reilly, A.; McShane, G. J.; Chen, Y. C.; Wang, L.; Robson, J.; Prangnell, P.

    2016-09-01

    This paper presents a finite element thermal model for similar and dissimilar alloy friction stir spot welding (FSSW). The model is calibrated and validated using instrumented lap joints in Al-Al and Al-Fe automotive sheet alloys. The model successfully predicts the thermal histories for a range of process conditions. The resulting temperature histories are used to predict the growth of intermetallic phases at the interface in Al-Fe welds. Temperature predictions were used to study the evolution of hardness of a precipitation-hardened aluminum alloy during post-weld aging after FSSW.

  11. Explosive destruction of 26Al

    NASA Astrophysics Data System (ADS)

    Kahl, D.; Yamaguchi, H.; Shimizu, H.; Abe, K.; Beliuskina, O.; Cha, S. M.; Chae, K. Y.; Ge, Z.; Hayakawa, S.; Kwag, M. S.; Kim, D. H.; Moon, J. Y.; Park, S. Y.; Yang, L.

    2017-09-01

    The γ -ray emission associated with the radioactive decay of 26Al is one of the key pieces of observational evidence indicating stellar nucleosynthesis is an ongoing process in our Galaxy, and it was the first such radioactivity to be detected. Despite numerous efforts in stellar modeling, observation, nuclear theory, and nuclear experiment over the past four decades, the precise sites and origin of Galactic ^{26} Al remain elusive. We explore the present experimental knowledge concerning the destruction of ^{26} Al in massive stars. The precise stellar rates of neutron-induced reactions on ^{26} Al, such as (n,p) and (n, α , have among the largest impacts on the total ^{26} Al yield. Meanwhile, reactions involving the short-lived isomeric state of ^{26} Al such as radiative proton capture are highly-uncertain at present. Although we presented on-going experimental work from n_TOF at CERN with an ^{26} Al target, the present proceeding focuses only on the ^{26} Al isomeric radioactive beam production aspect and the first experimental results at CRIB.

  12. Philosophieren als Unterrichtsprinzip im Mathematikunterricht

    NASA Astrophysics Data System (ADS)

    Meerwaldt, Diana

    Philosophieren und Mathematik scheinen zunächst gegensätzliche Bereiche zu sein, die sich kaum vereinbaren lassen. Dies trifft für eine Auffassung zu, die Philosophieren als "Gerede" disqualifiziert und Mathematik als eine reine "Formelwissenschaft" begreift. Beide Auffassungen werden den Gegenständen nicht gerecht.

  13. Deformation mechanisms of nanotwinned Al

    SciTech Connect

    Zhang, Xinghang

    2016-11-10

    The objective of this project is to investigate the role of different types of layer interfaces on the formation of high density stacking fault (SF) in Al in Al/fcc multilayers, and understand the corresponding deformation mechanisms of the films. Stacking faults or twins can be intentionally introduced (via growth) into certain fcc metals with low stacking fault energy (such as Cu, Ag and 330 stainless steels) to achieve high strength, high ductility, superior thermal stability and good electrical conductivity. However it is still a major challenge to synthesize these types of defects into metals with high stacking fault energy, suchmore » as Al. Although deformation twins have been observed in some nanocrystalline Al powders by low temperature, high strain rate cryomilling or in Al at the edge of crack tip or indentation (with the assistance of high stress intensity factor), these deformation techniques typically introduce twins sporadically and the control of deformation twin density in Al is still not feasible. This project is designed to test the following hypotheses: (1) Certain type of layer interfaces may assist the formation of SF in Al, (2) Al with high density SF may have deformation mechanisms drastically different from those of coarse-grained Al and nanotwinned Cu. To test these hypotheses, we have performed the following tasks: (i) Investigate the influence of layer interfaces, stresses and deposition parameters on the formation and density of SF in Al. (ii) Understand the role of SF on the deformation behavior of Al. In situ nanoindentation experiments will be performed to probe deformation mechanisms in Al. The major findings related to the formation mechanism of twins and mechanical behavior of nanotwinned metals include the followings: 1) Our studies show that nanotwins can be introduced into metals with high stacking fault energy, in drastic contrast to the general anticipation. 2) We show two strategies that can effectively introduce growth

  14. Deformation mechanisms of nanotwinned Al

    SciTech Connect

    Zhang, Xinghang

    2016-11-10

    The objective of this project is to investigate the role of different types of layer interfaces on the formation of high density stacking fault (SF) in Al in Al/fcc multilayers, and understand the corresponding deformation mechanisms of the films. Stacking faults or twins can be intentionally introduced (via growth) into certain fcc metals with low stacking fault energy (such as Cu, Ag and 330 stainless steels) to achieve high strength, high ductility, superior thermal stability and good electrical conductivity. However it is still a major challenge to synthesize these types of defects into metals with high stacking fault energy, such as Al. Although deformation twins have been observed in some nanocrystalline Al powders by low temperature, high strain rate cryomilling or in Al at the edge of crack tip or indentation (with the assistance of high stress intensity factor), these deformation techniques typically introduce twins sporadically and the control of deformation twin density in Al is still not feasible. This project is designed to test the following hypotheses: (1) Certain type of layer interfaces may assist the formation of SF in Al, (2) Al with high density SF may have deformation mechanisms drastically different from those of coarse-grained Al and nanotwinned Cu. To test these hypotheses, we have performed the following tasks: (i) Investigate the influence of layer interfaces, stresses and deposition parameters on the formation and density of SF in Al. (ii) Understand the role of SF on the deformation behavior of Al. In situ nanoindentation experiments will be performed to probe deformation mechanisms in Al. The major findings related to the formation mechanism of twins and mechanical behavior of nanotwinned metals include the followings: 1) Our studies show that nanotwins can be introduced into metals with high stacking fault energy, in drastic contrast to the general anticipation. 2) We show two strategies that can effectively introduce growth twins in

  15. Proximity effects in Nb/Al-AlOx-Al/Nb superconducting tunneling junctions

    NASA Astrophysics Data System (ADS)

    Zehnder, A.; Lerch, Ph.; Zhao, S. P.; Nussbaumer, Th.; Kirk, E. C.; Ott, H. R.

    1999-04-01

    Experimental investigations of the proximity effects in symmetric Nb/Al-AlOx-Al/Nb superconducting tunneling junctions with a fixed Nb thickness of 200 nm, and Al layer thicknesses ranging from 4 to 120 nm, are reported. Both dc Josephson-tunneling and quasiparticle-tunneling current voltage characteristics were measured, and analyzed using the proximity effect model proposed by Golubov and Kupriyanov. The numerical computations were performed without the approximation used by Golubov et al. In particular, the order parameter was allowed to spatially vary in Nb and Al and the Usadel functions were not linearized. The overall shape of the experimental I-V curves, as well as the temperature dependence of the dc Josephson current and of the gap energies are satisfactorily reproduced by the model calculations provided the parameter γBN describing the resistance at the Al-Nb interface is taken into account. From γBN we extract a value for the quasiparticle transmission at the Nb/Al interface which is smaller than unity.

  16. Frequently Asked Questions about ALS and the ALS Registry

    MedlinePlus

    ... web portal with those in the large national databases. Only approved staff working on the National ALS ... All your data are encrypted in the registry database. Every night we move the personal identifiable information ( ...

  17. Medical application of 26Al

    NASA Astrophysics Data System (ADS)

    Steinhausen, C.; Gerisch, P.; Heisinger, B.; Hohl, Ch.; Kislinger, G.; Korschinek, G.; Niedermayer, M.; Nolte, E.; Dumitru, M.; Alvarez-Brückmann, M.; Schneider, M.; Ittel, T. H.

    1996-06-01

    Accelerator mass spectrometry (AMS) measurements with 26Al as tracer were performed in order to study the aluminium metabolism and anomalies in the human body and in rats. In particular, the differences between healthy volunteers and patients with renal failure were investigated. The obtained data points of 26Al in blood and urine were described by an open compartment model with three peripheral compartments. It was found that the minimum of peripheral compartments needed to describe 26Al concentrations in blood and urine over a time period of three years is at least three.

  18. Reply to Gopalswamy et al.

    NASA Technical Reports Server (NTRS)

    Cane, H. V.; Richardson, I. G.

    2003-01-01

    The comment of Gopalswamy et al. (thereafter GMY) relates to a letter discussing coronal mass ejections (CMEs), interplanetary ejecta and geomagnetic storms. GMY contend that Cane et al. incorrectly identified ejecta (interplanetary CMEs) and hypothesize that this is because Cane et al. fail to understand how to separate ejecta from "shock sheaths" when interpreting solar wind and energetic particle data sets. They (GMY) are wrong be cause the relevant section of the paper was concerned with the propagation time to 1 AU of any potentially geoeffective structures caused by CMEs, i.e. upstream compression regions with or without shocks, or ejecta. In other words, the travel times used by Cane et al. were purposefully and deliberately distinct from ejecta travel times (except for those slow ejecta, approx. 30% of their events, which generated no upstream features), and no error in identification was involved. The confusion of GMY stems from the description did not characterize the observations sufficiently clearly.

  19. Al-Au-La (010)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Au-La (010)' with the content:

  20. Al-Cu-Zr (050)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Cu-Zr (050)' with the content:

  1. Al-Ce-V (029)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/97.etType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Ce-V (029)' with the content:

  2. Al-Co-Fe (030)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Co-Fe (030)' with the content:

  3. Al-La-Ni (069)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-La-Ni (069)' with the content:

  4. Al-La-Nb (068)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/97.etType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-La-Nb (068)' with the content:

  5. Comparing the Thermodynamic Behaviour of Al(1)+ZrO2(s) to Al(1)+Al2O3(s)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2004-01-01

    In an effort to better determine the thermodynamic properties of Al(g) and Al2O(g). the vapor in equilibrium with Al(l)+ZrO2(s) was compared to the vapor in equilibrium with Al(l)+Al2O3(s) over temperature range 1197-to-1509K. The comparison was made directly by Knudsen effusion-cell mass spectrometry with an instrument configured for a multiple effusion-cell vapor source (multi-cell KEMS). Second law enthalpies of vaporization of Al(g) and Al2O(g) together with activity measurements show that Al(l)+ZrO2(s) is thermodynamically equivalent to Al(l)+Al2O3(s), indicating Al(l) remained pure and Al2O3(s) was present in the ZrO2-cell. Subsequent observation of the Al(l)/ZrO2 and vapor/ZrO2 interfaces revealed a thin Al2O3-layer had formed, separating the ZrO2-cell from Al(l) and Al(g)+Al2O(g), effectively transforming it into an Al2O3 effusion-cell. This behavior agrees with recent observations made for Beta-NiAl(Pt) alloys measured in ZrO2 effusion-cell.

  6. Overdamped Nb /Al-AlOx/Nb Josephson junctions

    NASA Astrophysics Data System (ADS)

    Lacquaniti, V.; Cagliero, C.; Maggi, S.; Steni, R.

    2005-01-01

    We report the fabrication and characterization of overdamped Nb /Al-AlOx/Nb superconductor-insulator-superconductor Josephson junction whose fabrication process derives from that of the well-known hysteretic junctions. These junctions are an intermediate state between the superconductor-normal metal-superconductor and the superconductor-insulator-superconductor Josephson junctions. Stable and reproducible nonhysteretic current-voltage characteristics are obtained with a proper choice of the fabrication parameters. We have measured critical current densities JC from 103 up to 2×104A/cm2, with characteristic voltages from 80 to nearly 450μV. The junctions are stable against time and repeated thermal cycling.

  7. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    SciTech Connect

    Yadav, S. K. E-mail: yadav.satyesh@gmail.com Liu, X.-Y. E-mail: yadav.satyesh@gmail.com; Wang, J.

    2016-06-14

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. The formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamically driven process.

  8. Wadi Al Dawasir, Saudi Arabia

    NASA Image and Video Library

    2015-10-20

    In the middle of the Arabian desert the city Green Oasis Wadi Al Dawasir is being developed as a new urban center for the Wadi Al Dawasir region of Saudi Arabia, as shown in this image from NASA Terra spacecraft. Huge solar fields supply the entire city and the surrounding region with energy. Hundreds of circular agricultural fields are fed by center pivot irrigation apparatus, drawing water from subterranean aquifers. The image was acquired March 30, 2013, covers an area of 30 x 45 km, and is located at 20.2 degrees north, 44.8 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA20077

  9. Dynamic Modeling of ALS Systems

    NASA Technical Reports Server (NTRS)

    Jones, Harry

    2002-01-01

    The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

  10. AlGaN solar-blind avalanche photodiodes with AlInN/AlGaN distributed Bragg reflectors

    NASA Astrophysics Data System (ADS)

    Yao, Chujun; Ye, Xuanchao; Sun, Rui; Yang, Guofeng; Wang, Jin; Lu, Yanan; Yan, Pengfei; Cao, Jintao

    2017-06-01

    AlGaN solar-blind avalanche photodiodes (APDs) with AlInN/AlGaN distributed Bragg reflectors (DBRs) operated at lower avalanche breakdown voltage are numerically demonstrated. The p-type AlGaN layer and the multiplicative layer with low Al composition are introduced to construct the polarization-induced electric field, which can significantly reduce the avalanche breakdown voltage of the APDs. Calculated results exhibit that the avalanche breakdown voltage of the designed APDs decrease by 13% compared with the conventional device structure. Simultaneously, an improved solar-blind spectral responsivity is achieved due to the inserted AlInN/AlGaN DBRs.

  11. Stem cells therapy for ALS.

    PubMed

    Mazzini, Letizia; Vescovi, Angelo; Cantello, Roberto; Gelati, Maurizio; Vercelli, Alessandro

    2016-01-01

    Despite knowledge on the molecular basis of amyotrophic lateral sclerosis (ALS) having quickly progressed over the last few years, such discoveries have not yet translated into new therapeutics. With the advancement of stem cell technologies there is hope for stem cell therapeutics as novel treatments for ALS. We discuss in detail the therapeutic potential of different types of stem cells in preclinical and clinical works. Moreover, we address many open questions in clinical translation. SC therapy is a potentially promising new treatment for ALS and the need to better understand how to develop cell-based experimental treatments, and how to implement them in clinical trials, becomes more pressing. Mesenchymal stem cells and neural fetal stem cells have emerged as safe and potentially effective cell types, but there is a need to carry out appropriately designed experimental studies to verify their long-term safety and possibly efficacy. Moreover, the cost-benefit analysis of the results must take into account the quality of life of the patients as a major end point. It is our opinion that a multicenter international clinical program aime d at fine-tuning and coordinating transplantation procedures and protocols is mandatory.

  12. [Current treatment of AL amyloidosis].

    PubMed

    Desport, Estelle; Moumas, Eric; Abraham, Julie; Delbès, Sébastien; Lacotte-Thierry, Laurence; Touchard, Guy; Fermand, Jean-Paul; Bridoux, Frank; Jaccard, Arnaud

    2011-11-01

    Systemic AL amyloidosis is a rare complication of monoclonal gammopathies. Renal manifestations are frequent, mostly characterized by heavy proteinuria, with nephrotic syndrome and renal failure in more than half of the patients at diagnosis. Without treatment, median survival does not exceed 12 months. Amyloid heart disease and diffusion of amyloid deposits are associated with reduced survival. Treatment of systemic AL amyloidosis has been profoundly modified with the introduction of international criteria for the definition of organ involvement and hematologic response, and with the use of sensitive tests for the measurement of serum-free light chain levels. Melphalan plus dexamethasone is now established as the gold standard for first line treatment of systemic AL, with similar efficacy and reduced treatment-related mortality compared to high-dose therapy. Modern chemotherapy regimens, based on the use of novel agents such as bortezomib and lenalidomide, might further improve patient survival. Copyright © 2011 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

  13. Al-Qaeda-Syria (AQS): An Al-Qaeda Affiliate Case Study

    DTIC Science & Technology

    2017-10-01

    network. 6 Cafarella, The Threat of New Al-Qaeda Leadership, p. 2. 7 Charles Lister, “Al-Qa’ida Plays a Long Game in Syria,” CTC Sentinel 8, no...Jabhat al-Nusra’s Rebranding as Jabhat Fateh al- Sham,” CTC Sentinel 9, no. 8 (2016), https://www.ctc.usma.edu/posts/al-qaida-uncoupling- jabhat-al...Tamimi, Aymenn. “Al-Qa’ida Uncoupling: Jabhat al-Nusra’s Rebranding as Jabhat Fateh al- Sham.” CTC Sentinel 9, no. 8 (August 2016). Accessed July 26

  14. Investigations of Al-Dalang and Al-Hawashat meteorites

    NASA Astrophysics Data System (ADS)

    Gismelseed, A. M.; Abdallah, S. B.; Al-Rawas, A. D.; Al-Mabsali, F. N.; Widatallah, H. M.; Elzain, M. E.; Yousif, A. A.; Ericsson, T.; Annersten, H.

    2016-12-01

    Mössbauer spectroscopy, X-ray diffraction (XRD) measurements, and electron microprobe analysis (EMPA) have been performed on two meteorites named Al-Dalang and Al-Hawashat after identifying their falling sites in the Western region of Sudan. These two meteorites are ordinary chondrites with similar mineralogy. XRD and EMPA show that the two specimens consist of primary olivine, ortho-pyroxene and later crystallising clino-pyroxene as reaction rims against plagioclase. Fe-metal phases are dominated by kamacite (≈6 wt.% Ni) and minor amounts of tetrataenite (≈52 wt.% Ni). Troilite (FeS) and alabandite (MnS) are optically observed as sulphide phases. The Mössbauer measurements at 295 and 78 K are in agreement with the above characterizations, showing at least two paramagnetic doublets which are assigned to olivine and pyroxene and magnetic sextets assigned to kamacite (hyperfine field ≈33.5 T) and troilite FeS (hyperfine field ≈31 T).

  15. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    DOE PAGES

    Yadav, S. K.; Wang, J.; Liu, X. -Y.

    2016-06-13

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. Furthermore, the formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamicallymore » driven process.« less

  16. NiAl-base composite containing high volume fraction of AlN for advanced engines

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan (Inventor); Whittenbeger, John D. (Inventor); Lowell, Carl F. (Inventor)

    1994-01-01

    A particulate reinforced NiAl-AlN composite alloy has a NiAl matrix and greater than about 13 volume percent fine particles of AlN within the matrix. The particles preferably have a diameter from about 15 nanometers to about 50 nanometers. The particulate reinforced NiAl-AlN composite alloy may be prepared by cryomilling prealloyed NiAl in liquid nitrogen using grinding media having a diameter of from about 2 to 6 mm at an impeller speed of from about 450 RPM to about 800 RPM. The cryomilling may be done for a duration of from about 4 hours to about 20 hours to obtain a cryomilled powder. The cryomilled powder may be consolidated to form the particulate reinforced NiAl-AlN composite alloy. The particulate reinforced alloy can further include a toughening alloy. The toughening alloy may include NiCrAlY, FeCrAlY, and FeAl.

  17. Benefits for Military Veterans with ALS

    MedlinePlus

    ... Chapters Certified Centers and Clinics Support Groups About ALS About Us Our Research In Your Community Advocate ... Veterans Resources for Military Veterans, Families & Survivors The ALS Association is working everyday to support people with ...

  18. Cenomanian-Turonian biostratigraphy of the Jardas Al Abid area, Al Jabal Al Akhdar, northeast Libya

    NASA Astrophysics Data System (ADS)

    El Qot, Gamal M.; Abdulsamad, Esam O.

    2016-09-01

    The Upper Cenomanian-Turonian succession exposed at Jardas al'Abid area consists mainly of carbonates with siliciclastic intercalations. This succession is subdivided lithostratigraphically into: Qasr al'Abid (Late Cenomanian) and Al Baniyah (Late Cenomanian-Coniacian) formations. This sequence is relatively rich in macrofossil assemblages especially bivalves, gastropods, and echinoids with rare ammonites. Based on the first occurrence (FO) and last occurrence (LO) of some index species of these macrofossil groups, an integrated biostratigraphic framework has been constructed. The studied Cenomanian-Turonian sequence is subdivided biostratigraphically into three ammonite biozones; Pseudaspidoceras pseudonodosoides Total Range Zone, Choffaticeras segne Total Range Zone, and Coilopoceras requienianum Total Range Zone. Based on the rest of macrofossil assemblages other than the ammonites, eight biozones were recognized; Mecaster batnensis Total Range Zone, Ceratostreon flabellatum-Neithea dutrugei Acme Zone, Costagyra olisiponensis Acme Zone, Pycnodonte (Phygraea) vesicularis vesiculosa Acme Zone, Mytiloides labiatus Total Range Zone = Mecaster turonensis Acme Zone, Rachiosoma rectilineatum-Curvostrea rouvillei-Tylostoma (T.) globosum Assemblage Zone, Radiolites sp.-Apricardia? matheroni Total Range Zone, and Nerinea requieniana Total Range Zone. Most of the proposed biozones are recorded for the first time from Libya. The integration among these biozones as well as local and inter-regional correlation of the biozones have been discussed. The stage boundaries of the studied stratigraphic intervals are discussed, where the Cenomanian/Turonian boundary is delineated at the last occurrence (LO) of Pseudaspidoceras pseudonodosoides (Choffat), while the Turonian/Coniacian boundary is delineated arbitrary being agree with the LO of the Turonian fauna.

  19. Opportunity's 'Rub al Khali' Panorama

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Opportunity's 'Rub al Khali' Panorama (QTVR)

    This panoramic image, dubbed 'Rub al Khali,' was acquired by NASA's Mars Exploration Rover Opportunity on the plains of Meridiani during the period from the rover's 456th to 464th sols on Mars (May 6 to May 14, 2005). Opportunity was about 2 kilometers (1.2 miles) south of 'Endurance Crater' at a place known informally as 'Purgatory Dune.'

    The rover was stuck in the dune's deep fine sand for more than a month. 'Rub al Khali' (Arabic translation: 'the empty quarter') was chosen as the name for this panorama because it is the name of a similarly barren, desolate part of the Saudi Arabian desert on Earth.

    The view spans 360 degrees. It consists of images obtained in 97 individual pointings of the panoramic camera. The camera took images with five camera filters at each pointing. This 22,780-by-6,000-pixel mosaic is an approximately true-color rendering generated using the images acquired through filters admitting light wavelengths of 750, 530, and 480 nanometers.

    Lighting varied during the nine sols it took to acquire this panorama, resulting in some small image seams within the mosaic. These seams have been smoothed in sky parts of the mosaic to better simulate the vista that a person would see if able to view it all at the same time on Mars.

    Opportunity's tracks leading back to the north (center of the panorama) are a reminder of the rover's long trek from Endurance Crater. The deep ruts dug by Opportunity's wheels as it became stuck in the sand appear in the foreground. The crest and trough of the last ripple the rover crossed before getting stuck is visible in the center. These wind-formed sand features are only about 10 to 15 centimeters (4 to 6 inches) tall. The crest of the actual ripple where the rover got stuck can be seen just to the right of center. The tracks and a few other places on and near ripple crests can

  20. Nonstoichiometry of Al-Zr intermetallic phases

    SciTech Connect

    Radmilovic, V.; Thomas, G.

    1994-06-01

    Nonstoichiometry of metastable cubic {beta}{prime} and equilibrium tetragonal {beta} Al-Zr intermetallic phases of the nominal composition Al{sub 3}Zr in Al-rich alloys has been extensively studied. It is proposed that the ``dark contrast`` of {beta}{prime} core in {beta}{prime}/{sigma}{prime} complex precipitates, in Al-Li-Zr based alloys, is caused by incorporation of Al and Li atoms into the {beta}{prime} phase on Zr sublattice sites, forming nonstoichiometric Al-Zr intermetallic phases, rather than by Li partitioning only. {beta}{prime} particles contain very small amounts of Zr, approximately 5 at.%, much less than the stoichiometric 25 at.% in the Al{sub 3}Zr metastable phase. These particles are, according tomore » simulation of high resolution images, of the Al{sub 3}(Al{sub 0.4}Li{sub 0.4}Zr{sub 0.2}) type. Nonstoichiometric particles of average composition Al{sub 4}Zr and Al{sub 6}Zr are observed also in the binary Al-Zr alloy, even after annealing for several hours at 600{degree}C.« less

  1. Elevated temperature compressive properties of reaction milled NiAl-AlN and Zr-doped NiAl-AlN composites

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.; Luton, Michael J.

    1992-01-01

    Previous studies of a single lot of NiAl powder which had been ground under high intensity conditions in liquid nitrogen (cryomilling) indicated that this processing leads to a high strength, elevated temperature NiAl-AlN composite. Because this was the first known example of the use of the reaction milling process to produce a high temperature composite, the reproducibility of this technique was unknown. Two additional lots of NIAl powder and a lot of a Zr-doped NiAl powder have been cryomilled, and analyses indicate that AlN was formed within a NiAl matrix in all three cases. Compression testing between 1200 K and 1400 K has shown that the deformation resistance of these heats is similar to that of the first lot of NiAl-AlN; thus cryomilling can improve the creep resistance of NiAl by a factor of six. Based on this work, it is concluded that cryomilling of NiAl powder to form high temperature, high strength NiAl-AlN composites is a reproducible process.

  2. Aluminium distribution in ZSM-5 revisited: The role of Al-Al interactions

    SciTech Connect

    Ruiz-Salvador, A. Rabdel; Grau-Crespo, Ricardo; Gray, Aileen E.; Lewis, Dewi W.

    2013-02-15

    We present a theoretical study of the distribution of Al atoms in zeolite ZSM-5 with Si/Al=47, where we focus on the role of Al-Al interactions rather than on the energetics of Al/Si substitutions at individual sites. Using interatomic potential methods, we evaluate the energies of the full set of symmetrically independent configurations of Al siting in a Si{sub 94}Al{sub 2}O{sub 192} cell. The equilibrium Al distribution is determined by the interplay of two factors: the energetics of the Al/Si substitution at an individual site, which tends to populate particular T sites (e.g., the T14 site), and the Al-Al interaction, which at this Si/Al maximises Al-Al distances in general agreement with Dempsey's rule. However, it is found that the interaction energy changes approximately as the inverse of the square of the distance between the two Al atoms, rather than the inverse of the distance expected if this were merely charge repulsion. Moreover, we find that the anisotropic nature of the framework density plays an important role in determining the magnitude of the interactions, which are not simply dependent on Al-Al distances. - Graphical abstract: Role of Al-Al interactions in high silica ZSM-5 is shown to be anisotropic in nature and not dependent solely on Coulombic interactions. Highlights: Black-Right-Pointing-Pointer Si-Al distribution in ZSM-5 is revisited, stressing the role of the Al-Al interaction. Black-Right-Pointing-Pointer Coulomb interactions are not the key factors controlling the Al siting. Black-Right-Pointing-Pointer Anisotropy of the framework is identified as a source of departure from Dempsey's rule.

  3. Instandhaltungsmanagement als Gestaltungsfeld Ganzheitlicher Produktionssysteme

    NASA Astrophysics Data System (ADS)

    Dombrowski, Uwe; Schulze, Sven; Otano, Isabel Crespo

    Sich kontinuierlich verändernde Rahmenbedingungen, wie beispielsweise eine steigende Variantenvielfalt, verkürzte Produktlebenszyklen sowie Kundenforderungen nach höherer Qualität, kürzeren Lieferzeiten und geringeren Kosten, fordern von produzierenden Unternehmen eine stetige Anpassung der Prozesse, der Organisation und der Strukturen. Seit den 90er Jahren versuchen immer mehr deutsche Unternehmen diesen veränderten Anforderungen mit der Einführung eines Ganzheitlichen Produktionssystems (GPS) zu begegnen. Ganzheitliche Produktionssysteme sind dabei in ihren Grundlagen an das Toyota Produktionssystem angelehnt, vereinigen aber auch weitere Methoden zu einem unternehmensspezifischen Regelwerk. Im Rahmen des langfristigen Trends zu unternehmensindividuellen Produktionssystemen wird sowohl in der Industrie als auch in der Forschung intensiv über das Toyota Produktionssystem, Lean Production, Lean Management und Ganzheitliche Produktionssysteme diskutiert, werden Konzepte zu Implementierung und Betrieb erstellt und die Wirtschaftlichkeit untersucht.

  4. Cyclic oxidation resistance of a reaction milled NiAl-AlN composite

    NASA Technical Reports Server (NTRS)

    Lowell, Carl E.; Barrett, Charles A.; Whittenberger, J. D.

    1990-01-01

    Based upon recent mechanical property tests a NiAl-AlN composite produced by cryomilling has very attractive high temperature strength. This paper focuses on the oxidation resistance of the NiAl-AlN composite at 1473 and 1573 K as compared to that of Ni-47Al-0.15Zr, one of the most oxidation resistant intermetallics. The results of cyclic oxidation tests show that the NiAl-AlN composite has excellent properties although not quite as good as those of Ni-47Al-0.15Zr. The onset of failure of the NiAl-AlN was unique in that it was not accompanied by a change in scale composition from alumina to less protective oxides. Failure in the composite appears to be related to the entrapment of AlN particles within the alumina scale.

  5. Systems Engineering Techniques for ALS Decision Making

    NASA Technical Reports Server (NTRS)

    Rodriquez, Luis F.; Drysdale, Alan E.; Jones, Harry; Levri, Julie A.

    2004-01-01

    The Advanced Life Support (ALS) Metric is the predominant tool for predicting the cost of ALS systems. Metric goals for the ALS Program are daunting, requiring a threefold increase in the ALS Metric by 2010. Confounding the problem, the rate new ALS technologies reach the maturity required for consideration in the ALS Metric and the rate at which new configurations are developed is slow, limiting the search space and potentially giving the perspective of a ALS technology, the ALS Metric may remain elusive. This paper is a sequel to a paper published in the proceedings of the 2003 ICES conference entitled, "Managing to the metric: an approach to optimizing life support costs." The conclusions of that paper state that the largest contributors to the ALS Metric should be targeted by ALS researchers and management for maximum metric reductions. Certainly, these areas potentially offer large potential benefits to future ALS missions; however, the ALS Metric is not the only decision-making tool available to the community. To facilitate decision-making within the ALS community a combination of metrics should be utilized, such as the Equivalent System Mass (ESM)-based ALS metric, but also those available through techniques such as life cycle costing and faithful consideration of the sensitivity of the assumed models and data. Often a lack of data is cited as the reason why these techniques are not considered for utilization. An existing database development effort within the ALS community, known as OPIS, may provide the opportunity to collect the necessary information to enable the proposed systems analyses. A review of these additional analysis techniques is provided, focusing on the data necessary to enable these. The discussion is concluded by proposing how the data may be utilized by analysts in the future.

  6. Magnetism of Al-substituted magnetite reduced from Al-hematite

    NASA Astrophysics Data System (ADS)

    Jiang, Zhaoxia; Liu, Qingsong; Zhao, Xiang; Roberts, Andrew P.; Heslop, David; Barrón, Vidal; Torrent, José

    2016-06-01

    Aluminum-substituted magnetite (Al-magnetite) reduced from Al-substituted hematite or goethite (Al-hematite or Al-goethite) is an environmentally important constituent of magnetically enhanced soils. In order to characterize the magnetic properties of Al-magnetite, two series of Al-magnetite samples were synthesized through reduction of Al-hematite by a mixed gas (80% CO2 and 20% CO) at 395°C for 72 h in a quartz tube furnace. Al-magnetite samples inherited the morphology of their parent Al-hematite samples, but only those transformed from Al-hematite synthesized at low temperature possessed surficial micropores, which originated from the release of structural water during heating. Surface micropores could thus serve as a practical fingerprint of fire or other high-temperature mineralogical alteration processes in natural environments, e.g., shear friction in seismic zones. In addition, Al substitution greatly affects the magnetic properties of Al-magnetite. For example, coercivity (Bc) increases with increasing Al content and then decreases slightly, while the saturation magnetization (Ms), Curie temperature (Tc), and Verwey transition temperature (Tv) all decrease with increasing Al content due to crystal defect formation and dilution of magnetic ions caused by Al incorporation. Moreover, different trends in the correlation between Tc and Bc can be used to discriminate titanomagnetite from Al-magnetite, which is likely to be important in environmental and paleomagnetic studies, particularly in soil.

  7. Piezo-tunnel effect in Al/Al2O3/Al junctions elaborated by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Rafael, R.; Puyoo, E.; Malhaire, C.

    2017-11-01

    In this work, the electrical transport in Al/Al2O3/Al junctions under mechanical stress is investigated in the perspective to use them as strain sensors. The metal/insulator/metal junctions are elaborated with a low temperature process (≤200 °C) fully compatible with CMOS back-end-of-line. The conduction mechanism in the structure is found to be Fowler-Nordheim tunneling, and efforts are made to extract the relevant physical parameters. Gauge factors up to -32.5 were found in the fabricated devices under tensile stress. Finally, theoretical mechanical considerations give strong evidence that strain sensitivity in Al/Al2O3/Al structures originates not only from geometrical deformations but also from the variation of interface barrier height and/or effective electronic mass in the tunneling oxide layer.

  8. Nano-Crystalline Aluminum Alloys Based on Al-Fe, Al-Cu and Al-Sc Systems

    DTIC Science & Technology

    2010-06-14

    106mm diameter), Cu (99.9% purity and 53-106mm diameter) and Zr (99.9% purity and 53-106mm diameter) powders and Al3Zr and Sc2O3 powders were used in...following SPS processing Figure 9 microstructures of Al-1.5Cu alloy (a) SEM and (b) TEM a b a b The Sc was added to the Al powders as Sc2O3 which...the microstructure, compared with samples SPS processed at 400oC, Figure 11. Figure 10 (a) XRD spectra recorded from Al10wt% Sc2O3 containing

  9. Ti{sub 2}AlN thin films synthesized by annealing of (Ti+Al)/AlN multilayers

    SciTech Connect

    Cabioch, Thierry; Alkazaz, Malaz; Beaufort, Marie-France; Nicolai, Julien; Eyidi, Dominique; Eklund, Per

    2016-08-15

    Highlights: • Epitaxial thin films of the MAX phase Ti{sub 2}AlN are obtained by thermal annealing. • A new metastable (Ti,Al,N) solid solution with the structure of α-T is evidenced. • The formation of the MAX phase occurs at low temperature (600 °C). - Abstract: Single-phase Ti{sub 2}AlN thin films were obtained by annealing in vacuum of (Ti + Al)/AlN multilayers deposited at room temperature by magnetron sputtering onto single-crystalline (0001) 4H-SiC and (0001) Al{sub 2}O{sub 3} substrates. In-situ X-ray diffraction experiments combined with ex-situ cross-sectional transmission electron microscopy observations reveal that interdiffusion processes occur in the multilayer at a temperature of ∼400 °C leading to the formation of a (Ti, Al, N) solid solution, having the hexagonal structure of α-Ti, whereas the formation of Ti{sub 2}AlN occurs at 550–600 °C. Highly oriented (0002) Ti{sub 2}AlN thin films can be obtained after an annealing at 750 °C.

  10. Interfacial phenomena in the reactions of Al-B, Al-Ti-B, and Al-Zr-B alloys with KF-AlF{sub 3} and NaF-AlF{sub 3} melts

    SciTech Connect

    Lee, M.S.; Terry, B.S.; Grieveson, P.

    1993-12-01

    The interfacial phenomena occurring during the contacting of liquid Al-B, Al-Ti-B, and Al-Zr-B melts with KF-AlF{sub 3} liquid fluxes have been investigated by optical examination of quenched metal drops previously immersed in the liquid fluxes. Reactions in the Al-B/KF-AlF{sub 3} system involve the formation of metastable AlB{sub 12} at the metal/flux interface. At high KBF{sub 4} levels in the flux, the AlB{sub 12} is dispersed in the flux and also at low KBF{sub 4} levels in the metal. Reactions in the Al-Ti-B/KF-AlF{sub 3} system involve the formation of TiB{sub 2}, which may be dispersed in either the metal or themore » flux depending upon the composition of the flux. The results obtained for the Al-Ti-B/NaF-AlF{sub 3} and Al-Zr-B/KF-AlF{sub 3} systems were similar to those observed for the Al-Ti-B/KF-AlF{sub 3} system.« less

  11. Al Pie De La Letra

    PubMed Central

    Ovbiagele, Bruce

    2014-01-01

    Background and Purpose Ethnic minorities are at higher stroke risk than non-Hispanic whites yet are less likely to have optimal vascular risk factor control. There is a need to develop culturally sensitive strategies for enhancing vascular risk reduction in minority patients with stroke. This study aimed to develop a postdischarge report card to boost treatment adherence among elderly Spanish-speaking patients with stroke within an urban health system. Methods This study included a total of 13 Spanish-only speaking participants aged ≥60 years discharged from a local government hospital in Los Angeles within 18 months of an index ischemic stroke and 6 caregivers engaged in focus groups and interviews. Structured interviews were conducted with 11 care providers and 9 administrators at the hospital. Framework analysis examined the data and elicited themes to adapt a pre-existing patient report card tool. Results Spontaneously using the same phrase, “Al pie de la letra,” several participants expressed a need to follow medical instructions accurately to prevent recurrent stroke and identified barriers/facilitators for doing so. They made comments about the pre-existing report card, advising several changes, including the clarification of phrases, and written instructions to explain the need for the card and how to fill it out. The providers and administrators recommended avenues for successfully using the card at the hospital. A new report card was created that incorporated all major perspectives. Conclusions Crafting a culturally sensitive tool for promoting treatment adherence in elderly Spanish-only-speaking patients with stroke within an urban health system using a participatory methodology is feasible. The efficacy of this new report card should be tested in a randomized controlled trial. PMID:20167904

  12. Hypermetabolism as a Risk Factor for ALS

    DTIC Science & Technology

    2013-09-01

    Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis . Science 314, 130–133 (2006). 2. Weihl, C. C. et al . TDP-43...1-0449 TITLE: Hypermetabolism as a Risk Factor for ALS PRINCIPAL INVESTIGATOR: Philip C. Wong, Ph.D...Factor for ALS 5b. GRANT NUMBER W81XWH-11-1-0449 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Philip C. Wong, Ph.D. 5d. PROJECT

  13. Orientation relationship of eutectoid FeAl and FeAl2

    PubMed Central

    Scherf, A.; Kauffmann, A.; Kauffmann-Weiss, S.; Scherer, T.; Li, X.; Stein, F.; Heilmaier, M.

    2016-01-01

    Fe–Al alloys in the aluminium range of 55–65 at.% exhibit a lamellar microstructure of B2-ordered FeAl and triclinic FeAl2, which is caused by a eutectoid decomposition of the high-temperature Fe5Al8 phase, the so-called ∊ phase. The orientation relationship of FeAl and FeAl2 has previously been studied by Bastin et al. [J. Cryst. Growth (1978 ▸), 43, 745] and Hirata et al. [Philos. Mag. Lett. (2008 ▸), 88, 491]. Since both results are based on different crystallographic data regarding FeAl2, the data are re-evaluated with respect to a recent re-determination of the FeAl2 phase provided by Chumak et al. [Acta Cryst. (2010 ▸), C66, i87]. It is found that both orientation relationships match subsequent to a rotation operation of 180° about a 〈112〉 crystallographic axis of FeAl or by applying the inversion symmetry of the FeAl2 crystal structure as suggested by the Chumak data set. Experimental evidence for the validity of the previously determined orientation relationships was found in as-cast fully lamellar material (random texture) as well as directionally solidified material (∼〈110〉FeAl || solidification direction) by means of orientation imaging microscopy and global texture measurements. In addition, a preferential interface between FeAl and FeAl2 was identified by means of trace analyses using cross sectioning with a focused ion beam. On the basis of these habit planes the orientation relationship between the two phases can be described by (01)FeAl || (114) and [111]FeAl || [10]. There is no evidence for twinning within FeAl lamellae or alternating orientations of FeAl lamellae. Based on the determined orientation and interface data, an atomistic model of the structure relationship of Fe5Al8, FeAl and FeAl2 in the vicinity of the eutectoid decomposition is derived. This model is analysed with respect to the strain which has to be accommodated at the interface of FeAl and FeAl2. PMID:27047304

  14. Diffusion Bonding of TiAl to Ti6Al4V Using Nanolayers

    NASA Astrophysics Data System (ADS)

    Simões, Sónia; Viana, Filomena; Ramos, A. Sofia; Vieira, M. Teresa; Vieira, Manuel F.

    2018-01-01

    Microstructural characterization of TiAl to Ti6Al4V dissimilar diffusion bonds assisted by reactive Ni/Al nanolayers was performed in this study. The nanolayers (alternated Al and Ni) were deposited onto the base material surfaces. Diffusion bonding was performed at 700 and 800 °C under pressures from 5 to 40 MPa and dwell times between 60 and 180 min. Microstructural characterization was performed using high-resolution transmission and scanning electron microscopies. The observations revealed that dissimilar TiAl to Ti6Al4V joints assisted by Ni/Al reactive nanolayers can be obtained successfully at 800 °C during 60 min using a pressure of 20 MPa. The bond interface is thin (less than 10 µm) and is mainly composed of NiAl grains. Thin layers of Al-Ni-Ti intermetallic compounds were formed adjacent to the base materials.

  15. Effects of Al Contents on Carburization Behavior and Corrosion Resistance of TiAl Alloys

    NASA Astrophysics Data System (ADS)

    Liao, Cui Jiao; He, Yue Hui; Ming, Xing Zu

    2015-10-01

    TiAl alloys with Al contents of 30.7, 37, 46.5, and 54.2 at.% were carburized. Corrosion resistance of the untreated and the carburized TiAl alloys was comparatively analyzed. The phase and microstructure of the carburized TiAl alloys were studied by x-ray diffraction and scanning electron microscopy, respectively. Electrochemical corrosion behavior of the untreated and the carburized TiAl alloys was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy. Experimental results indicate that different Al contents bring about distinct microstructure of the carburized layers. The lower Al content leads to the formation of the thicker binary carbides and the thinner Ti2AlC phase. Additionally, the lower Al content leads to higher corrosion resistance in the untreated and the carburized states.

  16. Growth and stress-induced transformation of zinc blende AlN layers in Al-AlN-TiN multilayers

    DOE PAGES

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; ...

    2015-12-18

    We report that AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN.

  17. Decoding ALS: From Genes to Mechanism

    PubMed Central

    Taylor, J. Paul; Brown, Robert H.; Cleveland, Don W.

    2017-01-01

    Preface Amyotrophic lateral sclerosis (ALS) is a progressive and uniformly fatal neurodegenerative disease. A plethora of genetic factors underlying ALS have now been identified that drive motor neuron degeneration, increase susceptibility to the disease, or influence the rate of progression. Emerging themes include dysfunction in RNA metabolism and protein homeostasis, with specific defects in nucleocytoplasmic trafficking, induction of endoplasmic reticulum stress, and impaired dynamics of ribonucleoprotein bodies such as RNA granules that assemble through the process of liquid-liquid phase separation. Extraordinary recent progress in understanding the biology of ALS provides new grounds for optimism that meaningful therapies for ALS will be identified. PMID:27830784

  18. Genetics of Familial and Sporadic ALS

    ClinicalTrials.gov

    2017-01-04

    Amyotrophic Lateral Sclerosis (ALS); Familial Amyotrophic Lateral Sclerosis; Amyotrophic Lateral Sclerosis With Frontotemporal Dementia; Lou Gehrig's Disease; Motor Neuron Disease; Primary Lateral Sclerosis

  19. Superbend era begins swiftly at the ALS

    SciTech Connect

    Robinson, Art; Tamura, Lori

    2001-11-29

    The successful installation and commissioning of high-field superconducting bend magnets (superbends) in three curved sectors of ALS storage ring was the first time the magnet lattice of an operating synchrotron light source has been retrofitted in this fundamental way. As a result, the ALS now offers an expanded spectral range well into the hard x-ray region without compromising either the number of undulators or their high brightness in the soft x-ray region for which the ALS design was originally optimized. In sum, when the superbend-enhanced ALS started up for user operations in October 2001, it marked the beginning of a new era in its history.

  20. Tensile Behavior of Al2o3/feal + B and Al2o3/fecraly Composites

    NASA Technical Reports Server (NTRS)

    Draper, S. L.; Eldridge, J. I.; Aiken, B. J. M.

    1995-01-01

    The feasibility of Al2O3/FeAl + B and Al2O3/FeCrAlY composites for high-temperature applications was assessed. The major emphasis was on tensile behavior of both the monolithics and composites from 298 to 1100 K. However, the study also included determining the chemical compatibility of the composites, measuring the interfacial shear strengths, and investigating the effect of processing on the strength of the single-crystal Al2O3 fibers. The interfacial shear strengths were low for Al203/FeAl + B and moderate to high for Al203/FeCrAlY. The difference in interfacial bond strengths between the two systems affected the tensile behavior of the composites. The strength of the Al203 fiber was significantly degraded after composite processing for both composite systems and resulted in poor composite tensile properties. The ultimate tensile strength (UTS) values of the composites could generally be predicted with either rule of mixtures (ROM) calculations or existing models when using the strength of the etched-out fiber. The Al2O3/FeAl + B composite system was determined to be unfeasible due to poor interfacial shear strengths and a large mismatch in coefficient of thermal expansion (CTE). Development of the Al2O3/FeCrAlY system would require an effective diffusion barrier to minimize the fiber strength degradation during processing and elevated temperature service.

  1. Aluminium rhizotoxicity in maize grown in solutions with Al3+ or Al(OH)-4 as predominant solution Al species.

    PubMed

    Stass, A; Wang, Y; Eticha, D; Horst, W J

    2006-01-01

    The rhizotoxicity of aluminium at low-pH with Al(3+) and at high pH with Al(OH)-(4) as the main Al species was studied. Aluminium reduced root growth to similar levels at pH 8.0 and pH 4.3, although the mononuclear Al concentration at pH 8.0 was three times lower than at pH 4.3. Al contents of root apices were much higher at pH 8 than at pH 4.3. Callose was induced only marginally at pH 8 and the formation was confined to the epidermis, whereas it proceeded through the cortex with time at pH 4.3. Well-documented genotypical differences in callose formation and Al accumulation could not be found at pH 8. The largest fraction of the root-tip Al was recovered in the cell-wall fraction independent of the solution pH. A sequential extraction of isolated cell walls suggests that most of the cell-wall Al was precipitated Al(OH)(3) at pH 8.0. This can be explained by a drastic pH reduction in the root apoplastic sap to 6.2, whereas at bulk solution pH 4.3 it rose to 5.6. Al precipitation was also confirmed by the microscopic localization of Al. At pH 8, Al could mostly be found in the epidermis, but in the apoplast of the outer cortex at pH 4.3. It is proposed here that at pH 4.3, Al(3+) inhibits root growth through binding to sensitive binding sites in the apoplast of the epidermis and the outer cortex. At pH 8, Al(OH)(3) precipitation in the epidermis causes a mechanical barrier thus impairing the root-growth control of the epidermis.

  2. Processing and Mechanical Properties of Directionally Solidified NiAl/NiAlTa Alloys

    NASA Technical Reports Server (NTRS)

    Johnson, D. R.; Oliver, B. F.; Noebe, R. D.; Whittenberger, J. D.

    1994-01-01

    Promising creep strengths were found for a directionally solidified NiAl-NiAlTa alloy when compared to other NiAl based intermetallics. The directionally solidified alloy had an off-eutectic composition that resulted in microstructures consisting of NiAl dendrites surrounded by aligned eutectic regions. The room temperature toughness of the two phase alloy was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa. Alloying additions that may improve the room temperature toughness by producing multiphase alloys are discussed.

  3. Optical phonon scattering on electronic mobility in Al2O3/AlGaN/AlN/GaN heterostructures

    NASA Astrophysics Data System (ADS)

    Zhou, X. J.; Qu, Y.; Ban, S. L.; Wang, Z. P.

    2017-12-01

    Considering the built-in electric fields and the two-mode property of transverse optical phonons in AlGaN material, the electronic eigen-energies and wave functions are obtained by solving Schrödinger equation with the finite difference method. The dispersion relations and potentials of the optical phonons are given by the transfer matrix method. The mobility of the two dimensional electron gas influenced by the optical phonons in Al2O3/AlGaN/AlN/GaN heterostructures is investigated based on the theory of Lei-Ting force balance equation. It is found that the scattering from the half-space phonons is the main factor affecting the electronic mobility, and the influence of the other phonons can be ignored. The results show that the mobility decreases with increasing the thicknesses of Al2O3 and AlN layers, but there is no definite relationship between the mobility and the thickness of AlGaN barrier. The mobility is obviously reduced by increasing Al component in AlGaN crystal to show that the effect of ternary mixed crystals is important. It is also found that the mobility increases first and then decreases as the increment of the fixed charges, but decreases always with increasing temperature. The heterostructures constructed here can be good candidates as metal-oxide-semiconductor high-electron-mobility-transistors since they have higher electronic mobility due to the influence from interface phonons weakened by the AlN interlayer.

  4. Nuevas Perspectivas en la Efficiencia del Uso Nirogeno en Vaca Lecheras

    USDA-ARS?s Scientific Manuscript database

    Dairy cows utilize feed crude protein (CP) with greater efficiency than other ruminants, but still excrete about 2 to 3 times more nitrogen (N) in manure than they secrete in milk. This increases milk production costs plus environmental N pollution. Optimizing microbial protein formation in the rume...

  5. MEJORANDO LA UTILIZACION DE LA PROTEINA EN LA VACA LECHERA EN LACTANCIA

    USDA-ARS?s Scientific Manuscript database

    Dairy cows utilize feed CP with greater efficiency than other ruminants, but still excrete about 2 to 3 times more N in manure than they secrete in milk. This increases milk production costs plus environmental N pollution. Maximizing microbial protein formation in the rumen is the most effective way...

  6. ESTRATEGIAS PARA HACER EL MEJOR USO DE LA PROTEINA EN RACIONES PARA VACAS LECHERAS

    USDA-ARS?s Scientific Manuscript database

    Dairy cows utilize feed CP with greater efficiency than other ruminants, but still excrete about 2 to 3 times more N in manure than they secrete in milk. This increases milk production costs plus environmental N pollution. Optimizing microbial protein formation in the rumen is the most effective way...

  7. Microstructural and Phase Composition Differences Across the Interfaces in Al/Ti/Al Explosively Welded Clads

    NASA Astrophysics Data System (ADS)

    Fronczek, Dagmara Malgorzata; Chulist, Robert; Litynska-Dobrzynska, Lidia; Lopez, Gabriel Alejandro; Wierzbicka-Miernik, Anna; Schell, Norbert; Szulc, Zygmunt; Wojewoda-Budka, Joanna

    2017-09-01

    The microstructure and phase composition of Al/Ti/Al interfaces with respect to their localization were investigated. An aluminum-flyer plate exhibited finer grains located close to the upper interface than those present within the aluminum-base plate. The same tendency, but with a higher number of twins, was observed for titanium. Good quality bonding with a wavy shape and four intermetallic phases, namely, TiAl3, TiAl, TiAl2, and Ti3Al, was only obtained at the interface closer to the explosive material. The other interface was planar with three intermetallic compounds, excluding the metastable TiAl2 phase. As a result of a 100-hour annealing at 903 K (630 °C), an Al/TiAl3/Ti/TiAl3/Al sandwich was manufactured, formed with single crystalline Al layers. A substantial difference between the intermetallic layer thicknesses was measured, with 235.3 and 167.4 µm obtained for the layers corresponding to the upper and lower interfaces, respectively. An examination by transmission electron microscopy of a thin foil taken from the interface area after a 1-hour annealing at 825 K (552 °C) showed a mixture of randomly located TiAl3 grains within the aluminum. Finally, the hardness results were correlated with the microstructural changes across the samples.

  8. Sporadic and hereditary amyotrophic lateral sclerosis (ALS).

    PubMed

    Ajroud-Driss, Senda; Siddique, Teepu

    2015-04-01

    Genetic discoveries in ALS have a significant impact on deciphering molecular mechanisms of motor neuron degeneration. The identification of SOD1 as the first genetic cause of ALS led to the engineering of the SOD1 mouse, the backbone of ALS research, and set the stage for future genetic breakthroughs. In addition, careful analysis of ALS pathology added valuable pieces to the ALS puzzle. From this joint effort, major pathogenic pathways emerged. Whereas the study of TDP43, FUS and C9ORF72 pointed to the possible involvement of RNA biology in motor neuron survival, recent work on P62 and UBQLN2 refocused research on protein degradation pathways. Despite all these efforts, the etiology of most cases of sporadic ALS remains elusive. Newly acquired genomic tools now allow the identification of genetic and epigenetic factors that can either increase ALS risk or modulate disease phenotype. These developments will certainly allow for better disease modeling to identify novel therapeutic targets for ALS. This article is part of a Special Issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. What is "Hyper" in the ALS Hypermetabolism?

    PubMed

    Ferri, Alberto; Coccurello, Roberto

    2017-01-01

    The progressive and fatal loss of upper (brain) and lower (spinal cord) motor neurons and muscle denervation concisely condenses the clinical picture of amyotrophic lateral sclerosis (ALS). Despite the multiple mechanisms believed to underlie the selective loss of motor neurons, ALS aetiology remains elusive and obscure. Likewise, there is also a cluster of alterations in ALS patients in which muscle wasting, body weight loss, eating dysfunction, and abnormal energy dissipation coexist. Defective energy metabolism characterizes the ALS progression, and such paradox of energy balance stands as a challenge for the understanding of ALS pathogenesis. The hypermetabolism in ALS will be examined from tissue-specific energy imbalance (e.g., skeletal muscle) to major energetic pathways (e.g., AMP-activated protein kinase) and whole-body energy alterations including glucose and lipid metabolism, nutrition, and potential involvement of interorgan communication. From the point of view here expressed, the hypermetabolism in ALS should be evaluated as a magnifying glass through which looking at the ALS pathogenesis is from a different perspective in which defective metabolism can disclose novel mechanistic interpretations and lines of intervention.

  10. Durability Assessment of TiAl Alloys

    NASA Technical Reports Server (NTRS)

    Draper, Susan L.; Lerch, Bradley A.

    2008-01-01

    The durability of TiAl is a prime concern for the implementation of TiAl into aerospace engines. Two durability issues, the effect of high temperature exposure on mechanical properties and impact resistance, have been investigated and the results are summarized in this paper. Exposure to elevated temperatures has been shown to be detrimental to the room temperature ductility of gamma alloys with the most likely mechanisms being the ingress of interstitials from the surface. Fluorine ion implantation has been shown to improve the oxidation resistance of gamma alloys, and ideally it could also improve the environmental embrittlement of high Nb content TiAl alloys. The effect of F ion implantation on the surface oxidation and embrittlement of a third generation, high Nb content TiAl alloy (Ti-45Al-5Nb-B-C) were investigated. Additionally, the ballistic impact resistance of a variety of gamma alloys, including Ti-48Al-2Cr- 2Nb, Ti-47Al-2Cr-2Nb, ABB-2, ABB-23, NCG359E, 95A and Ti-45Al-5Nb-B-C was accessed. Differences in the ballistic impact properties of the various alloys will be discussed, particularly with respect to their manufacturing process, microstructure, and tensile properties.

  11. AlAs: camel's back parameter

    NASA Astrophysics Data System (ADS)

    Fernandes da Silva, E. C.

    This document is part of Volume 44 `Semiconductors', Subvolume A `New Data and Updates for I-VII, III-V, III-VI and IV-VI Compounds' of Landolt-Börnstein Group III `Condensed Matter'. It contains data on AlAs (aluminum arsenide), Element System Al-As.

  12. Diana Al-Hadid: Identity and Heritage

    ERIC Educational Resources Information Center

    Jungerberg, Tom; Smith, Anna; Borsh, Colleen

    2012-01-01

    Diana Al-Hadid's sculptures reflect the many locations, cultures, histories, and mythologies that have shaped her as an artist. In large-scale works which have the appearance of architectural ruins, Al-Hadid employs imagery drawn from many diverse interests including science and technology, history, and literature. She also incorporates images and…

  13. Energetics of Al13 Keggin cluster compounds

    PubMed Central

    Armstrong, Christopher R.; Casey, William H.; Navrotsky, Alexandra

    2011-01-01

    The ϵ-Al13 Keggin aluminum hydroxide clusters are essential models in establishing molecular pathways for geochemical reactions. Enthalpies of formation are reported for two salts of aluminum centered ϵ-Keggin clusters, Al13 selenate, (Na(AlO4)Al12(OH)24(SeO4)4•12H2O) and Al13 sulfate, (NaAlO4Al12(OH)24(SO4)4•12H2O). The measured enthalpies of solution, ΔHsol, at 28 °C in 5 N HCl for the ε-Al13 selenate and sulfate are −924.57 (± 3.83) and −944.30 ( ± 5.66) kJ·mol-1, respectively. The enthalpies of formation from the elements, ΔHf,el, for Al13 selenate and sulfate are −19,656.35 ( ± 67.30) kJ·mol-1, and −20,892.39 ( ± 70.01) kJ·mol-1, respectively. In addition, ΔHf,el for sodium selenate decahydrate was calculated using data from high temperature oxide melt solution calorimetry measurements: −4,006.39 ( ± 11.91) kJ·mol-1. The formation of both ε-Al13 Keggin cluster compounds is exothermic from oxide-based components but energetically unfavorable with respect to a gibbsite-based assemblage. To understand the relative affinity of the ϵ-Keggin clusters for selenate and sulfate, the enthalpy associated with two S-Se exchange reactions was calculated. In the solid state, selenium is favored in the Al13 compound relative to the binary chalcogenate, while in 5 N HCl, sulfur is energetically favored in the cluster compound compared to the aqueous solution. This contribution represents the first thermodynamic study of ε-Al13 cluster compounds and establishes a method for other such molecules, including the substituted versions that have been created for kinetic studies. Underscoring the importance of ε-Al13 clusters in natural and anthropogenic systems, these data provide conclusive thermodynamic evidence that the Al13 Keggin cluster is a crucial intermediate species in the formation pathway from aqueous aluminum monomers to aluminum hydroxide precipitates. PMID:21852572

  14. NiAl alloys for structural uses

    NASA Technical Reports Server (NTRS)

    Koss, D. A.

    1991-01-01

    Alloys based on the intermetallic compound NiAl are of technological interest as high temperature structural alloys. These alloys possess a relatively low density, high melting temperature, good thermal conductivity, and (usually) good oxidation resistance. However, NiAl and NiAl-base alloys suffer from poor fracture resistance at low temperatures as well as inadequate creep strength at elevated temperatures. This research program explored macroalloying additions to NiAl-base alloys in order to identify possible alloying and processing routes which promote both low temperature fracture toughness and high temperature strength. Initial results from the study examined the additions of Fe, Co, and Hf on the microstructure, deformation, and fracture resistance of NiAl-based alloys. Of significance were the observations that the presence of the gamma-prime phase, based on Ni3Al, could enhance the fracture resistance if the gamma-prime were present as a continuous grain boundary film or 'necklace'; and the Ni-35Al-20Fe alloy was ductile in ribbon form despite a microstructure consisting solely of the B2 beta phase based on NiAl. The ductility inherent in the Ni-35Al-20Fe alloy was explored further in subsequent studies. Those results confirm the presence of ductility in the Ni-35Al-20Fe alloy after rapid cooling from 750 - 1000 C. However exposure at 550 C caused embrittlement; this was associated with an age-hardening reaction caused by the formation of Fe-rich precipitates. In contrast, to the Ni-35Al-20Fe alloy, exploratory research indicated that compositions in the range of Ni-35Al-12Fe retain the ordered B2 structure of NiAl, are ductile, and do not age-harden or embrittle after thermal exposure. Thus, our recent efforts have focused on the behavior of the Ni-35Al-12Fe alloy. A second parallel effort initiated in this program was to use an alternate processing technique, mechanical alloying, to improve the properties of NiAl-alloys. Mechanical alloying in the

  15. Delegitimizing Al-Qaeda: A Jihad-Realist Approach

    DTIC Science & Technology

    2012-03-01

    that fatally undercut the legal underpinnings of al-Qaeda’s modus operandi . (See, esp.: Sayyid Imam Abd-al-Aziz al-Sharif, Doctrine of Rationalization...counternarrative frame is not “genu- ine peaceful pro-Western mainstream Muslim seeking liberal democratic freedoms versus jihadist violent killer ...Wathiqat Tarshid Al-‘Aml Al-Jihadi fi Misr w’Al-Alam), November 2007, serialized in Al-Sharq al-Awsat in Arabic and partially avail- able on

  16. Photoelectrical, photophysical and photocatalytic properties of Al based MOFs: MIL-53(Al) and MIL-53-NH{sub 2}(Al)

    SciTech Connect

    An, Yang; Li, Huiliang; Liu, Yuanyuan, E-mail: yyliu@sdu.edu.cn

    2016-01-15

    Two Al based MOFs (MIL-53(Al) and MIL-53-NH{sub 2} (Al)) were synthesized, and their photoelectrical, photophysical and photocatalytic properties towards oxygen evolution from water were investigated. Different from the ligand to metal charge transfer process previously reported, we proposes a new photocatalytic mechanism based on electron tunneling according to the results of theoretical calculation, steady state and time resolved fluorescence spectra. The organic linkers absorb photons, giving rise to electrons and holes. Then, the photogenerated electrons tunnel through the AlO{sub 6}-octahedra, which not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activitymore » of Al based MOFs. - Graphical abstract: The photoelectrical, photophysical and photocatalytic properties towards oxygen evolution from water of two Al based MOFs were investigated. A new photocatalytic mechanism was proposed based on electron tunneling according to the results of both theoretical calculation and steady state, time resolved fluorescence spectra. The electron tunneling process not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activity of Al based MOFs.« less

  17. Corrosion Studies of 2195 Al-Li Alloy and 2219 Al Alloy with Differing Surface Treatments

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.

    1998-01-01

    Corrosion studies of 2195 Al-Li and 2219 Al alloys have been conducted using the scanning reference electrode technique (SRET) and the polarization resistance (PR) technique. The SRET was used to study corrosion mechanisms, while corrosion rate measurements were studied with the PR technique. Plates of Al203 blasted, soda blasted and conversion coated 2219 Al were coated with Deft primer and the corrosion rates studied with the EIS technique. Results from all of these studies are presented.

  18. Nucleation and Precipitation Strengthening in Dilute Al-Ti and Al-Zr Alloys

    NASA Astrophysics Data System (ADS)

    Knipling, Keith E.; Dunand, David C.; Seidman, David N.

    2007-10-01

    Two conventionally solidified Al-0.2Ti alloys (with 0.18 and 0.22 at. pct Ti) exhibit no hardening after aging up to 3200 hours at 375 °C or 425 °C. This is due to the absence of Al3Ti precipitation, as confirmed by electron microscopy and electrical conductivity measurements. By contrast, an Al-0.2Zr alloy (with 0.19 at. pct Zr) displays strong age hardening at both temperatures due to precipitation of Al3Zr (L12) within Zr-enriched dendritic regions. This discrepancy between the two alloys is explained within the context of the equilibrium phase diagrams: (1) the disparity in solid and liquid solubilities of Ti in α-Al is much greater than that of Zr in α-Al; and (2) the relatively small liquid solubility of Ti in α-Al limits the amount of solute retained in solid solution during solidification, while the comparatively high solid solubility reduces the supersaturation effecting precipitation during post-solidification aging. The lattice parameter mismatch of Al3Ti (L12) with α-Al is also larger than that of Al3Zr (L12), further hindering nucleation of Al3Ti. Classical nucleation theory indicates that the minimum solute supersaturation required to overcome the elastic strain energy of Al3Ti nuclei cannot be obtained during conventional solidification of Al-Ti alloys (unlike for Al-Zr alloys), thus explaining the absence of Al3Ti precipitation and the presence of Al3Zr precipitation.

  19. Japanese version of the ALS-FTD-Questionnaire (ALS-FTD-Q-J).

    PubMed

    Watanabe, Yasuhiro; Beeldman, Emma; Raaphorst, Joost; Izumi, Yuishin; Yoshino, Hiide; Masuda, Michihito; Atsuta, Naoki; Ito, Satoru; Adachi, Tadashi; Adachi, Yoshiki; Yokota, Osamu; Oda, Masaya; Hanashima, Ritsuko; Ogino, Mieko; Ichikawa, Hiroo; Hasegawa, Kazuko; Kimura, Hideki; Shimizu, Toshio; Aiba, Ikuko; Yabe, Hayato; Kanba, Makoto; Kusumi, Kimiyoshi; Aoki, Tetsuya; Hiroe, Yu; Watanabe, Hirohisa; Nishiyama, Kazutoshi; Nomoto, Masahiro; Sobue, Gen; Nakashima, Kenji

    2016-08-15

    Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) share common clinical, genetic and neuropathological features. Some ALS patients have behavioral/personality changes, which could result in significant obstacles in the care provided by family members and caregivers. An easy screening tool would contribute greatly to the evaluation of these symptoms. We translated the ALS-FTD-Questionnaire, developed in the Netherlands, into Japanese (ALS-FTD-Q-J) and examined the clinimetric properties (internal consistency, construct and clinical validity). Patients with ALS and/or behavioral variant FTD (bvFTD) were evaluated alongside healthy controls in this multicenter study. All ALS patients, regardless of bvFTD status, were further evaluated by the frontal behavioral inventory (FBI) and for frontal/executive function, cognition, anxiety/depression, and motor functions. Data from 146 subjects were analyzed: ALS (92), ALS-bvFTD (6), bvFTD (16), and healthy controls (32). The internal consistency of the ALS-FTD-Q-J was good (Cronbach α=0.92). The ALS-FTD-Q-J showed construct validity as it exhibited a high correlation with the FBI (r=0.79). However, correlations were moderate with anxiety/depression and low with cognitive scales, in contrast to the original report, i.e. a moderate correlation with cognition and a low correlation with anxiety/depression. The ALS-FTD-Q-J discriminated ALS patients from (ALS-)bvFTD patients and controls. Thus, the ALS-FTD-Q-J is useful for evaluating Japanese ALS/FTD patients. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. A new discontinuously reinforced aluminum MMC: Al+AlB{sub 2} flakes

    SciTech Connect

    HALL,AARON C.; ECONOMY,J.

    2000-06-08

    Development of a novel metal matrix composite based on the Al-B alloy system has been undertaken. Preparation of this discontinuously reinforced material is based on the precipitation of high aspect ratio AlB{sub 2} from an Al-B alloy. This paper describes a number of efforts forced on preparing high volume fractions (> 30 v%) of AlB{sub 2} in aluminum. New insights into the behavior of the Al-B alloys system allowed this effort to be successful.

  1. Atomistic Modeling of RuAl and (RuNi) Al Alloys

    NASA Technical Reports Server (NTRS)

    Gargano, Pablo; Mosca, Hugo; Bozzolo, Guillermo; Noebe, Ronald D.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Atomistic modeling of RuAl and RuAlNi alloys, using the BFS (Bozzolo-Ferrante-Smith) method for alloys is performed. The lattice parameter and energy of formation of B2 RuAl as a function of stoichiometry and the lattice parameter of (Ru(sub 50-x)Ni(sub x)Al(sub 50)) alloys as a function of Ni concentration are computed. BFS based Monte Carlo simulations indicate that compositions close to Ru25Ni25Al50 are single phase with no obvious evidence of a miscibility gap and separation of the individual B2 phases.

  2. [A strategy to develop effective ALS therapy].

    PubMed

    Mitsumoto, Hiroshi

    2007-04-01

    In the early 1990s, a number of major events took place in the history of the treatment and science of ALS. A cause of familial ALS, the mutation of superoxide dismutase 1, was discovered and very shortly after, an animal model expressing the human SOD1 mutation for familial ALS was generated. Around the same time, the first medication for the treatment of ALS, riluzole, was approved. Clinical neurologists started to focus more attention on quality of life and standardizing care for patients with ALS, including devising approaches for presenting and discussing the diagnosis, using aggressive symptomatic treatments, and developing a multidisciplinary care system. Since then, nutritional and respiratory care has markedly improved. Respiratory care for those with terminal ALS in Japan has been distinct and perhaps more effective compared to the rest of the world, and this unique experience must be broadly published and shared with others. In 1999, the ALS Treatment Guidelines were published by the American Academy of Neurology and are now under revision. A monitoring system to determine the impact the Guidelines had on actual patient care has taught us that caregivers have only slowly accepted the recommendation to improve quality of care. The team approach, using a multidisciplinary care system from diagnosis to the end of life, is essential to improve care for both the patient and family. Coinciding with the progress in ALS treatment, basic science and translational research also produced dramatic progress in ALS drug discovery. Over the past 15 years, more than 25 potential drugs have been tested in randomized controlled trials. Despite this progress, we have no medications other than riluzole. Although it may be true that ALS research is in its early stages compared to research in other diseases with no cure--it is probably behind cancer research by at least 20 or 30 years--we need to drastically change our approach to drug development. At a national level, we

  3. Reaction of Ti and Ti-Al alloys with alumina

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.

    1991-01-01

    The reaction of single-crystal Al2O3 with pure Ti and Ti-Al alloys with different Al concentrations was examined in the temperature range of 1173 to 1573 K. Significant reaction occurred between Al2O3 and the Ti-Al alloys with Al concentrations lower than that corresponding to the gamma-TiAl phase. The reaction mechanism was determined to be simultaneous diffusion of Al and atomic oxygen from Al2O3 into Ti and the Ti-Al alloys.

  4. ALS-Plus Syndrome: Non-Pyramidal Features in a Large ALS Cohort

    PubMed Central

    McCluskey, Leo; Vandriel, Shannon; Elman, Lauren; Van Deerlin, Vivianna M.; Powers, John; Boller, Ashley; Wood, Elisabeth McCarty; Woo, John; McMillan, Corey T.; Rascovsky, Katya; Grossman, Murray

    2014-01-01

    Objective Autopsy studies show widespread pathology in amyotrophic lateral sclerosis (ALS), but clinical surveys of multisystem disease in ALS are rare. We investigated ALS-Plus syndrome, an understudied group of patients with clinical features extending beyond pyramidal and neuromuscular systems with or without cognitive/behavioral deficits. Methods In a large, consecutively-ascertained cohort of 550 patients with ALS, we documented atypical clinical manifestations. Genetic screening for C9orf72 hexanucleotide expansions was performed in 343 patients, and SOD1, TARDBP, and VCP were tested in the subgroup of patients with a family history of ALS. Gray matter and white matter imaging was available in a subgroup of 30 patients. Results Seventy-five (13.6%) patients were identified with ALS-Plus syndrome. We found disorders of ocular motility, cerebellar, extrapyramidal and autonomic functioning. Relative to those without ALS-Plus, cognitive impairment (8.0% vs 2.9%, p=0.029), bulbar-onset (49.3% vs 23.2%, p<0.001), and pathogenic mutations (20.0% vs 8.4%, p=0.015) were more than twice as common in ALS-Plus. Survival was significantly shorter in ALS-Plus (29.66 months vs 42.50 months, p=0.02), regardless of bulbar-onset or mutation status. Imaging revealed significantly greater cerebellar and cerebral disease in ALS-Plus compared to those without ALS-Plus. Conclusions ALS-Plus syndrome is not uncommon, and the presence of these atypical features is consistent with neuropathological observations that ALS is a multisystem disorder. ALS-Plus syndrome is associated with increased risk for poor survival and the presence of a pathogenic mutation. PMID:25086858

  5. Electroforming and Ohmic contacts in Al-Al2O3-Ag diodes

    NASA Astrophysics Data System (ADS)

    Hickmott, T. W.

    2012-03-01

    Electroforming of metal-insulator-metal (MIM) diodes is a non-destructive dielectric breakdown process that changes the diode from its initial high resistance state (HRS) to a low resistance state (LRS). After electroforming, resistance switching memories (RSMs) use voltages to switch from HRS to LRS and back. Many MIM combinations are proposed for use in RSMs. In many cases conduction in the LRS is nearly temperature independent at low temperatures; an Ohmic contact with a barrier to electron injection of ˜0 eV results from electroforming. Electroforming of Al-Al2O3-Ag diodes with amorphous anodic Al2O3 thicknesses between 12 and 41 nm has been studied. Two anodizing electrolytes have been used; 0.1 M ammonium pentaborate (bor-H2O) and a solution of 0.1 M of ammonium pentaborate per liter of ethylene glycol (bor-gly). Polarization of Al2O3 and negative charge in Al2O3 are much larger when Al2O3 is formed in bor-H2O solution than when Al is anodized in bor-gly solution. Electroforming of Al-Al2O3-Ag diodes results in an Ohmic contact at the Al-Al2O3 interface, voltage-controlled negative resistance (VCNR) in the current-voltage (I-V) characteristics, electroluminescence (EL), and electron emission into vacuum (EM) from filamentary conducting channels. Two distinct modes of electroforming occur for Al-Al2O3-Ag diodes. α-forming occurs for 2.5 V ≲ VS ≲ 5 V, where VS is the applied voltage. It is characterized by an abrupt current jump with the simultaneous appearance of EL and EM. β-forming occurs for VS ≳ 7 V. I-V curves, EL, and EM develop gradually and are smaller than for α-forming. Electroforming occurs more readily for diodes with Al2O3 formed in bor-H2O that have greater defect densities. Fully developed I-V curves have similar VCNR, EL, and EM after α-forming or β-forming. A model is proposed in which excited states of F-centers, oxygen vacancies in amorphous anodic Al2O3, form defect conduction bands. Electroforming that results in an Ohmic

  6. Optical properties of TiAlC/TiAlCN/TiAlSiCN/TiAlSiCO/TiAlSiO tandem absorber coatings by phase-modulated spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Jyothi, J.; Biswas, A.; Sarkar, P.; Soum-Glaude, A.; Nagaraja, H. S.; Barshilia, Harish C.

    2017-07-01

    TiAlC, TiAlCN, TiAlSiCN, TiAlSiCO, and TiAlSiO layers of thicknesses 2.2 μm, 755, 491, 393, and 431 nm, respectively, were deposited on stainless steel, silicon, and glass substrates to study their refractive indices and extinction coefficients using the phase-modulated spectroscopic ellipsometry in the wavelength range of 300-1200 nm. Absorption coefficient of each layer was calculated from the extinction coefficient of the layer. The results indicate that the first three layers (i.e., TiAlC, TiAlCN, and TiAlSiCN) are absorbing in nature, while TiAlSiCO and TiAlSiO act as intermediate and antireflection layers. Subsequently, a tandem absorber of TiAlC/TiAlCN/TiAlSiCN/TiAlSiCO/TiAlSiO with layer thicknesses of 62, 20, 18, 16, and 27 nm, respectively, was deposited on stainless steel substrates to fabricate a spectrally selective coating with absorptance of 0.961 and emittance of 0.15 at 82 °C. The obtained refractive indices and extinction coefficients of the tandem absorber were used to simulate the reflectance of the deposited tandem absorber using SCOUT software. Simulated reflectance data of the tandem absorber showed a good agreement with the experimental data measured by UV-Vis-NIR and FTIR spectrophotometry. The angular dependence of the selective properties of the tandem absorber was studied by measuring the reflectance spectra of the tandem absorber at different incident angles.

  7. GdAlO3 perovskite.

    PubMed

    du Boulay, Douglas; Ishizawa, Nobuo; Maslen, Edward Ted N

    2004-12-01

    Flux-grown gadolinium aluminate perovskite, GdAlO(3), was examined using single-crystal 0.7 angstroms-wavelength synchrotron X-ray diffraction. In the context of other well categorized rare earth aluminate (RAlO(3)) perovskite phases, the orthorhombic Pnma symmetry determined for the current compound is unsurprising. Corner-linked AlO(6) octahedra form the structural backbone of RAlO(3) perovskites and distort to accommodate the various rare earth ions in the structural voids. For GdAlO(3), the octahedral distortion, characterized by tilting of the octahedra about the shortest R-Al-R vectors, and octahedral deformation, characterized by strain of the octahedra along those axes, are in accordance with trends in the RAlO(3) series.

  8. Pike International, LLC et al. Information Sheet

    EPA Pesticide Factsheets

    Pike International LLC, et al. (the Company) is located in New Haven, Connecticut. The Complaint involves the lease of, and renovation activities conducted at, property constructed prior to 1978, located in New Haven, Connecticut.

  9. 12th Annual ALS Users' Association Meeting

    SciTech Connect

    Robinson, Arthur L.

    1999-12-17

    Science took the front seat as 219 Advanced Light Source (ALS) users and staff gathered on Monday and Tuesday, October 18 and 19 for the twelfth annual users' meeting. The bulk of the meeting was dedicated to reports on science at the ALS. Packed into two busy days were 31 invited oral presentations and 80 submitted poster presentations, as well as time to visit 24 vendor booths. The oral sessions were dedicated to environmental science, chemical dynamics, biosciences, magnetic materials, and atomic and molecular science. In addition, there was an ALS highlights session that emphasized new results and a sessionmore » comprising highlights from the young scientists who will carry the ALS into the future.« less

  10. Superbend era begins swiftly at the ALS

    SciTech Connect

    Robinson, Art; Tamura, Lori

    2001-11-29

    The successful installation and commissioning of high-field superconducting bend magnets (superbends) in three curved sectors of ALS storage ring was the first time the magnet lattice of an operating synchrotron light source has been retrofitted in this fundamental way. As a result, the ALS now offers an expanded spectral range well into the hard x-ray region without compromising either the number of undulators or their high brightness in the soft x-ray region for which the ALS design was originally optimized. In sum, when the superbend-enhanced ALS started up for user operations in October 2001, it marked the beginning of amore » new era in its history.« less

  11. Ultrasonic dispersion of Al-AlN and Al2O3 nanopowder agglomerates and of nanostructured AlOOH particles

    NASA Astrophysics Data System (ADS)

    Ivanov, A. N.

    2012-05-01

    The influence of the ultrasonic radiation of power 10-60 W and frequency 22 and 2.64ṡ103 kHz on the deagglomeration of Al-AlN, Al2O3, and AlOOH nanopowders in ethanol has been studied by using a dynamic light scattering method. It has been shown that the number-average size of the agglomerates decreases to 0.5 μm during their ultrasound dispersion at a frequency of 22 kHz for 20 min and subsequently it does vary on varying insonation duration and ultrasonic power. Two-stage ultrasonic treatment of the agglomerates at frequencies of 22 and 2.64ṡ103 kHz increases the fraction of 0.2-0.5 μm particles. It has been found that efficient deagglomeration of nanopowders can be attained by sequentially increasing the ultrasonic radiation frequency.

  12. Structure of decagonal Al-Ni-Rh.

    PubMed

    Logvinovich, Dmitry; Simonov, Arkadiy; Steurer, Walter

    2014-08-01

    The crystal structure of the decagonal phase in the system Al-Ni-Rh (d-Al-Ni-Rh) was analyzed in the five-dimensional embedding approach based on single-crystal synchrotron X-ray diffraction data. The structure can be described as a quasiperiodic packing of partially overlapping decagonal and pentagonal columnar clusters with ∼ 21 Å diameter and ∼ 4 Å period along the tenfold axis.

  13. The evolving genetic risk for sporadic ALS.

    PubMed

    Gibson, Summer B; Downie, Jonathan M; Tsetsou, Spyridoula; Feusier, Julie E; Figueroa, Karla P; Bromberg, Mark B; Jorde, Lynn B; Pulst, Stefan M

    2017-07-18

    To estimate the genetic risk conferred by known amyotrophic lateral sclerosis (ALS)-associated genes to the pathogenesis of sporadic ALS (SALS) using variant allele frequencies combined with predicted variant pathogenicity. Whole exome sequencing and repeat expansion PCR of C9orf72 and ATXN2 were performed on 87 patients of European ancestry with SALS seen at the University of Utah. DNA variants that change the protein coding sequence of 31 ALS-associated genes were annotated to determine which were rare and deleterious as predicted by MetaSVM. The percentage of patients with SALS with a rare and deleterious variant or repeat expansion in an ALS-associated gene was calculated. An odds ratio analysis was performed comparing the burden of ALS-associated genes in patients with SALS vs 324 normal controls. Nineteen rare nonsynonymous variants in an ALS-associated gene, 2 of which were found in 2 different individuals, were identified in 21 patients with SALS. Further, 5 deleterious C9orf72 and 2 ATXN2 repeat expansions were identified. A total of 17.2% of patients with SALS had a rare and deleterious variant or repeat expansion in an ALS-associated gene. The genetic burden of ALS-associated genes in patients with SALS as predicted by MetaSVM was significantly higher than in normal controls. Previous analyses have identified SALS-predisposing variants only in terms of their rarity in normal control populations. By incorporating variant pathogenicity as well as variant frequency, we demonstrated that the genetic risk contributed by these genes for SALS is substantially lower than previous estimates. © 2017 American Academy of Neurology.

  14. 17th Annual ALS Users' Association Meeting

    SciTech Connect

    Robinson, Art; Tamura, Lori

    2004-11-29

    It's not exactly Russian roulette, but scheduling October events outdoors is not risk-free, even in usually sunny California. An overflow crowd of more than 400 registered users, ALS staff, and vendors enjoyed a full indoor program featuring science highlights and workshops spread over two and a half days from October 18 to October 20. However, a major storm, heralding the onset of the San Francisco Bay Area rainy season, posed a few weather challenges for the events on the ALS patio.

  15. The fecal microbiome of ALS patients.

    PubMed

    Brenner, David; Hiergeist, Andreas; Adis, Carolin; Mayer, Benjamin; Gessner, André; Ludolph, Albert C; Weishaupt, Jochen H

    2018-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative motor neuron disease accompanied by both systemic and central nervous system-specific inflammation as well as deregulated energy metabolism. These potential pathogenetic factors have recently been found to mutually interact with the gut microbiota, raising the hypothesis of a link between microbiome alterations and ALS pathogenesis. The aim of our study was to assess whether ALS is associated with an altered composition of the fecal microbiota. We compared the fecal microbiota of 25 ALS patients with 32 age- and gender-matched healthy persons using 16S rRNA gene sequencing analysis. Confounding factors and secondary disease effects on the microbiome were minimized by selection of patients without dysphagia, gastrostomy, noninvasive ventilation, or reduced body mass index. Comparing the 2 carefully matched groups, the diversity and the abundance of the bacterial taxa on the different taxonomic levels as well as PICRUSt-predicted metagenomes were almost indistinguishable. Significant differences between ALS patients and healthy controls were only observed with regard to the overall number of microbial species (operational taxonomic units) and in the abundance of uncultured Ruminococcaceae. Conclusively, ALS patients do not exhibit a substantial alteration of the gut microbiota composition. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Next-generation sequencing of 28 ALS-related genes in a Japanese ALS cohort.

    PubMed

    Nakamura, Ryoichi; Sone, Jun; Atsuta, Naoki; Tohnai, Genki; Watanabe, Hazuki; Yokoi, Daichi; Nakatochi, Masahiro; Watanabe, Hirohisa; Ito, Mizuki; Senda, Jo; Katsuno, Masahisa; Tanaka, Fumiaki; Li, Yuanzhe; Izumi, Yuishin; Morita, Mitsuya; Taniguchi, Akira; Kano, Osamu; Oda, Masaya; Kuwabara, Satoshi; Abe, Koji; Aiba, Ikuko; Okamoto, Koichi; Mizoguchi, Kouichi; Hasegawa, Kazuko; Aoki, Masashi; Hattori, Nobutaka; Tsuji, Shoji; Nakashima, Kenji; Kaji, Ryuji; Sobue, Gen

    2016-03-01

    We investigated the frequency and contribution of variants of the 28 known amyotrophic lateral sclerosis (ALS)-related genes in Japanese ALS patients. We designed a multiplex, polymerase chain reaction-based primer panel to amplify the coding regions of the 28 ALS-related genes and sequenced DNA samples from 257 Japanese ALS patients using an Ion Torrent PGM sequencer. We also performed exome sequencing and identified variants of the 28 genes in an additional 251 ALS patients using an Illumina HiSeq 2000 platform. We identified the known ALS pathogenic variants and predicted the functional properties of novel nonsynonymous variants in silico. These variants were confirmed by Sanger sequencing. Known pathogenic variants were identified in 19 (48.7%) of the 39 familial ALS patients and 14 (3.0%) of the 469 sporadic ALS patients. Thirty-two sporadic ALS patients (6.8%) harbored 1 or 2 novel nonsynonymous variants of ALS-related genes that might be deleterious. This study reports the first extensive genetic screening of Japanese ALS patients. These findings are useful for developing genetic screening and counseling strategies for such patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Magnetism in Fe4Al13 and related FeAl intermetallics

    NASA Astrophysics Data System (ADS)

    Chi, Ji; Li, Yang; Gou, Weiping; Goruganti, V.; Rathnayaka, K. D. D.; Ross, Joseph H., Jr.

    2006-03-01

    We report the results of an experimental study of FeAl alloys, including Fe4Al13, FeAl2 and Fe2Al5. By using NMR, dc magnetic susceptibility, and specific heat, we found that Fe4Al13 and Fe2Al5 are non-magnetic with some dilute magnetic moments, while FeAl2 can be characterized as a concentrated local moment system. Fe4Al13 is a decagonal quasicrystal approximant with 102 atoms in its unit cell. The ^27Al NMR spin-lattice relaxation indicates a very narrow pseudogap in the electronic density of states [g(E)] in the vicinity of the Fermi energy. The observations could be fit assuming a parabolic variation of g(E), consistent with observations in other quasicrystals and approximants. NMR lineshape measurements also agree with this analysis, and show that the system is dilute-magnetic, in strong contrast to the FeAl2 ordered intermetallic. We use specific heat to analyze the dilute moment density. This work was supported by the Robert A. Welch Foundation, Grant No. A-1526, by the National Science Foundation (DMR-0103455), and by Texas A&M University through the Telecommunications and Informatics Task Force.

  18. Atomistic simulation of Al-graphene thin film growth on polycrystalline Al substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Lan; Zhu, Yongchao; Li, Na; Rong, Yan; Xia, Huimin; Ma, Huizhong

    2018-03-01

    The growth of Al-Graphene composite coatings on polycrystalline Al substrate was investigated by using classical molecular dynamics (MD) simulations. Unlike the diffusion behaviors on single crystal surface, most of adatoms were easily bound by the steps on polycrystalline Al surface, owing to the local accelerated energy. Both Ehrlich-Schwoebel (ES) barriers and the steering effect backed up the volmer-weber growth mode, which was consistent with the dynamic growth process observed in the deposit. The morphology of composite coatings was significantly affected by graphene flakes. Enrichment of graphene flakes gave rise to an increase of the local thickness, and graphene flakes only existed in Al grain boundaries. The size of Al grains in the composite coating visibly decreased when compared with that in the pure Al coating. This grain refinement and the mechanical property can be reinforced by the increase of graphene flakes.

  19. TEM studies of oxidized NiAl and Ni3Al cross sections

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Ruhle, M.

    1989-01-01

    Cross sections of oxide scale/(Ni-Al) intermetallics were prepared by a new method and studied using primarily TEM. The cross sections were prepared by encasing an oxidized metal specimen sandwich in a low-melting-temperature zinc alloy. Observations of oxidized zirconium-doped beta-NiAl cross sections revealed crystallographic voids beneath an adherent Al2O3 scale. The oxide-metal interface was incoherent, but a high dislocation density in the metal near the interface suggested that a large tensile stress was induced by the attached oxide scale. A duplex Al2O3-NiAl2O4 scale formed on zirconium-doped and zirconium/boron-doped gamma-prime-Ni3Al alloys. Additional results are presented involving oxidation mechanisms and oxide-metal interface structures.

  20. Potential skin involvement in ALS: revisiting Charcot's observation - a review of skin abnormalities in ALS.

    PubMed

    Paré, Bastien; Gros-Louis, François

    2017-07-26

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting motor neurons of the brain and spinal cord, leading to progressive paralysis and death. Interestingly, many skin changes have been reported in ALS patients, but never as yet fully explained. These observations could be due to the common embryonic origin of the skin and neural tissue known as the ectodermal germ layer. Following the first observation in ALS patients' skin by Dr Charcot in the 19th century, in the absence of bedsores unlike other bedridden patients, other morphological and molecular changes have been observed. Thus, the skin could be of interest in the study of ALS and other neurodegenerative diseases. This review summarizes skin changes reported in the literature over the years and discusses about a novel in vitro ALS tissue-engineered skin model, derived from patients, for the study of ALS.

  1. Effects of Al(III) and Nano-Al13 Species on Malate Dehydrogenase Activity

    PubMed Central

    Yang, Xiaodi; Cai, Ling; Peng, Yu; Li, Huihui; Chen, Rong Fu; Shen, Ren Fang

    2011-01-01

    The effects of different aluminum species on malate dehydrogenase (MDH) activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT) modified glass carbon electrode (GCE). The results showed that Al(III) and Al13 can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al13 concentration increase. Our study also found that the effects of Al(III) and Al13 on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules. PMID:22163924

  2. Mechanical properties of Ni{sub 3}Al and FeAl: Recent developments

    SciTech Connect

    George, E.P.; Liu, C.T.

    1997-08-01

    Recent developments in the understanding of the ductility and fracture behavior of Ni{sub 3}Al and FeAl are reviewed. Both intrinsic factors (e.g., alloy stoichiometry), and extrinsic factors (e.g., environment) have been shown to affect their mechanical properties. Of all the recent developments, perhaps the most significant is the realization that Ni{sub 3}Al and FeAl are intrinsically ductile (at least on the Al-deficient side of stoichiometry); their brittleness when tested in ambient air is due mainly to environmental embrittlement. Another intriguing discovery is that boron embrittles Ni{sub 3}Al in gaseous hydrogen (until recently, B was though to have only beneficial, or at most neutral, effects). The authors review these and other recent discoveries and discuss, wherever possible, the underlying physical mechanisms giving rise to the observed mechanical behavior.

  3. The lowest ionization potentials of Al2

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Barnes, Leslie A.; Taylor, Peter R.

    1988-01-01

    Potential curves for the lowest two electronic states (X 2 sigma g + and A 2 pi u) of Al2(+) were computed using complete active space SCF/multireference CI wave functions and large Gaussian basis sets. The lowest observable vertical ionization potential (to Al2(+) X 2 sigma g +) of the Al2 X 3 pi u ground state is calculated to occur around 6.1 eV, in excellent agreement with the experimental range of 6.0 to 6.42 eV obtained in recent cluster ionization studies by Cox and co-workers. The second vertical ionization potential (to Al2(+) A 2 pi u) occurs near 6.4 eV, also within the experimental range. The adiabatic IP of 5.90 eV is in good agreement with the value of 5.8 to 6.1 eV deduced by Hanley and co-workers from the difference in thresholds between collision induced dissociation processes of Al3(+). The computed IP values are somewhat larger than those deduced from branching ratios in cluster fragmentation experiments by Jarrold and co-workers. The observation of an ionization threshold below 6.42 eV is shown to be incompatible with an Al2 ground electronic state assignment of 3 sigma g -, but the separation between the two lowest states of Al2 is so small that it is likely that both are populated in the experiments, so that this does not provide unambiguous support for the recent theoretical assignment of the ground state as 3 pi u.

  4. Quantum chemical study of the reactions of Al, AlO and AlOH with H2O2

    NASA Astrophysics Data System (ADS)

    Sharipov, Alexander S.; Starik, Alexander M.

    2016-02-01

    Quantum chemical calculations with the use of hybrid density functional with perturbative second-order correlation and dispersion correction are carried out to study the reactions of Al, AlO and AlOH with the H2O2 molecule. The values of energy barriers are estimated by means of extrapolation to the basis set limit. The energetically favorable reaction pathways have been revealed during the examination of the potential energy surfaces. Complex character of the processes under study has been established. It has been found that the initial stages of the considered processes are barrierless. Appropriate rate constants for principal channels of the reactions under study have been estimated by using capture model and canonical variational theory. The Arrhenius approximations for these channels have been proposed for the temperature range T = 300-4000 K.

  5. Assessing behavioural changes in ALS: cross-validation of ALS-specific measures.

    PubMed

    Pinto-Grau, Marta; Costello, Emmet; O'Connor, Sarah; Elamin, Marwa; Burke, Tom; Heverin, Mark; Pender, Niall; Hardiman, Orla

    2017-07-01

    The Beaumont Behavioural Inventory (BBI) is a behavioural proxy report for the assessment of behavioural changes in ALS. This tool has been validated against the FrSBe, a non-ALS-specific behavioural assessment, and further comparison of the BBI against a disease-specific tool was considered. This study cross-validates the BBI against the ALS-FTD-Q. Sixty ALS patients, 8% also meeting criteria for FTD, were recruited. All patients were evaluated using the BBI and the ALS-FTD-Q, completed by a carer. Correlational analysis was performed to assess construct validity. Precision, sensitivity, specificity, and overall accuracy of the BBI when compared to the ALS-FTD-Q, were obtained. The mean score of the whole sample on the BBI was 11.45 ± 13.06. ALS-FTD patients scored significantly higher than non-demented ALS patients (31.6 ± 14.64, 9.62 ± 11.38; p < 0.0001). A significant large positive correlation between the BBI and the ALS-FTD-Q was observed (r = 0.807, p < 0.0001), and no significant correlations between the BBI and other clinical/demographic characteristics indicate good convergent and discriminant validity, respectively. 72% of overall concordance was observed. Precision, sensitivity, and specificity for the classification of severely impaired patients were adequate. However, lower concordance in the classification of mild behavioural changes was observed, with higher sensitivity using the BBI, most likely secondary to BBI items which endorsed behavioural aspects not measured by the ALS-FTD-Q. Good construct validity has been further confirmed when the BBI is compared to an ALS-specific tool. Furthermore, the BBI is a more comprehensive behavioural assessment for ALS, as it measures the whole behavioural spectrum in this condition.

  6. Two-Phase (TiAl+TiCrAl) Coating Alloys for Titanium Aluminides

    NASA Technical Reports Server (NTRS)

    Brady, Michael P. (Inventor); Smialek, James L. (Inventor); Brindley, William J. (Inventor)

    1998-01-01

    A coating for protecting titanium aluminide alloys, including the TiAl gamma + Ti3Al (alpha(sub 2)) class, from oxidative attack and interstitial embrittlement at temperatures up to at least 1000 C. is disclosed. This protective coating consists essentially of titanium, aluminum. and chromium in the following approximate atomic ratio: Ti(41.5-34.5)Al(49-53)Cr(9.5-12.5)

  7. Unintentional incorporation of Ga in the nominal AlN spacer of AlInGaN/AlN/GaN Heterostructure

    NASA Astrophysics Data System (ADS)

    Dai, Shujun; Gao, Hongwei; Zhou, Yu; Zhong, Yaozong; Wang, Jin; He, Junlei; Zhou, Rui; Feng, Meixin; Sun, Qian; Yang, Hui

    2018-01-01

    Thin AlN spacer layer is widely adopted in Al(In)GaN/AlN/GaN heterostructures to improve the mobility of two-dimensional electron gas (2DEG) by increasing the 2DEG confinement and reducing the remote alloy scattering. However, the nominal AlN spacer is found to be an AlGaN spacer mainly due to the unintentional incorporation of Ga from the decomposition of the underlying GaN channel during the growth of AlN spacer and the temperature ramping process from the GaN channel to the Al(In)GaN barrier. The growth conditions of AlN spacer layer were varied systematically to study their influences on the unintentional Ga incorporation and the 2DEG mobility of AlInGaN/AlN/GaN heterostructures. Interestingly, the nominal AlN spacer (or AlGaN spacer in fact) can still effectively reduce the remote alloy scattering and deliver a 2DEG mobility substantially higher than that of AlInGaN/GaN heterostructures with no spacer or an AlGaN spacer uniformly containing a Ga content similar to the average Ga composition of the nominal AlN spacer. A simplified microstructure of the nominal AlN spacer with an inhomogeneous Ga incorporation was proposed to discuss about the influence of the spacer on the 2DEG mobility.

  8. ScPd2Al3 - New polymorphic phase in Al-Pd-Sc system

    NASA Astrophysics Data System (ADS)

    Pospíšil, Jiří; Haga, Yoshinori; Nakajima, Kunihisa; Ishikawa, Norito; Císařová, Ivana; Tateiwa, Naoyuki; Yamamoto, Etsuji; Yamamura, Tomoo

    2017-12-01

    We have discovered a new compound of the composition ScPd2Al3 crystallizing in unknown structure type. Moreover, ScPd2Al3 reveals polymorphism. We have found an orthorhombic crystal structure at room temperature and a high temperature cubic phase. The polymorphic phases are separated by a reversible first order transition at 1053 °C with a hysteresis of 19 °C. ScPd2Al3 exists as a very stable intermetallic phase just in the vicinity of the icosahedral quasicrystal Tsai-type i-phase Al54Pd30Sc16.

  9. Solid state reaction of Al and Zr in Al/Zr multilayers: A calorimetry study

    SciTech Connect

    Blobaum, K.J.; Weihs, T.P.; Barbee, T.W. Jr.

    1995-04-14

    The exothermic, solid state reaction of Al and Zr has been studied in thick Al/Zr multilayers using Differential Scanning Calorimetry and X-ray diffraction. The multilayer samples were magnetron sputter deposited into highly textured alternate layers of Al and Zr with nominal composition Al{sub 3}Zr. The samples used in this study were 47{mu}m thick with a 427{Angstrom} period. When samples were isochronally scanned from 25 to 725C, a large exotherm at {approximately}350C was followed by one or two smaller exotherms at {approximately}650C. The first exotherm is dominated by a diffusion based reaction of Al and Zr that produces two phases inmore » isochronal scans: amorphous Al-Zr and cubic Al{sub 3}Zr, and two additional phases in isothermal anneals: Al{sub 2}Zr and tetragonal Al{sub 3}Zr. The exothermic heat from this multi-phase reaction is measured using isochronal scans and isothermal anneals, and the heat flow is analyzed using a 1-D diffusion based model. An average activation energy and a diffusion constant are determined. In the isothermal scans, the total exothermic heat increases linearly with {radical}time, and layer thicknesses vary linearly with heat.« less

  10. Study on Mg/Al Weld Seam Based on Zn-Mg-Al Ternary Alloy.

    PubMed

    Liu, Liming; Liu, Fei; Zhu, Meili

    2014-02-13

    Based on the idea of alloying welding seams, a series of Zn- x Al filler metals was calculated and designed for joining Mg/Al dissimilar metals by gas tungsten arc (GTA) welding. An infrared thermography system was used to measure the temperature of the welding pool during the welding process to investigate the solidification process. It was found that the mechanical properties of the welded joints were improved with the increasing of the Al content in the Zn- x Al filler metals, and when Zn-30Al was used as the filler metal, the ultimate tensile strength could reach a maximum of 120 MPa. The reason for the average tensile strength of the joint increasing was that the weak zone of the joint using Zn-30Al filler metal was generated primarily by α-Al instead of MgZn 2. When Zn-40Al was used as the filler metal, a new transition zone, about 20 μm-wide, appeared in the edge of the fusion zone near the Mg base metal. Due to the transition zones consisting of MgZn₂- and Al-based solid solution, the mechanical property of the joints was deteriorated.

  11. Tensile behavior of directionally solidified Ni3Al intermetallics with different Al contents and solidification rates

    NASA Astrophysics Data System (ADS)

    Lu, Yun; Gu, Jiho; Kim, Sangshik; Hong, Hyunuk; Choi, Heekyu; Lee, Jehyun

    2014-03-01

    Despite the excellent high temperature mechanical properties of the Ni3Al intermetallic compound, its application is still limited due to its inherently weak grain boundary. Recent research advances have demonstrated that the tensile ductility can be enhanced by controlling the grain morphology using a directional solidification. In this study, a series of directional solidification experiments were carried out to increase both the tensile ductility and the strength of Ni3Al alloys by arraying either the ductile phase of γ-Ni-rich dendrite fibers or the hard phase of β-NiAl dendrite fibers in the γ'-Ni3Al matrix. The dendrite arm spacing could be controlled by the solidification rate, and the volume fraction of the γ or β phase could be altered by the Al content, ranging from 23 at.% to 27 at.%. With an increasing Al content, the γ dendritic microstructure was transformed into the β dendrite in the γ' matrix, thereby reducing the tensile ductility by increasing the volume fraction of brittle β dendrites in the γ' matrix. With an increasing solidification rate, the dendrite arm spacing decreased and the tensile properties of Ni3Al varied in a complex manner. The microstructural evolution affecting the tensile behavior of directionally solidified Ni3Al alloy specimens with different solidification rates and Al contents is discussed.

  12. Small Al clusters. II - Structure and binding in Al(n) (n = 2-6, 13)

    NASA Technical Reports Server (NTRS)

    Pettersson, Lars G. M.; Bauschlicher, Charles W., Jr.; Halicioglu, Timur

    1987-01-01

    The structure and stability of aluminum clusters containing up to six atoms have been studied using correlated wave functions and extended basis sets. The lowest energy structure is planar for Al4 and Al5, but three dimensional for Al6. The icosahedral, hcp, fcc, and two planar structures of Al13 were considered at the SCF level. The lowest energy structure is the icosahedron, but the planar structures are fairly low lying even in this case. A simplified description using two- and three-body interaction potentials is found to agree well with the ab initio structures and binding energies.

  13. Ohmic contacts to Al-rich AlGaN heterostructures

    DOE PAGES

    Douglas, E. A.; Reza, S.; Sanchez, C.; ...

    2017-06-06

    Due to the ultra-wide bandgap of Al-rich AlGaN, up to 5.8 eV for the structures in this study, obtaining low resistance ohmic contacts is inherently difficult to achieve. A comparative study of three different fabrication schemes is presented for obtaining ohmic contacts to an Al-rich AlGaN channel. Schottky-like behavior was observed for several different planar metallization stacks (and anneal temperatures), in addition to a dry-etch recess metallization contact scheme on Al 0.85Ga 0.15N/Al 0.66Ga 0.34N. However, a dry etch recess followed by n +-GaN regrowth fabrication process is reported as a means to obtain lower contact resistivity ohmic contacts onmore » a Al 0.85Ga 0.15N/Al 0.66Ga 0.34N heterostructure. In conclusion, specific contact resistivity of 5×10 -3 Ω cm 2 was achieved after annealing Ti/Al/Ni/Au metallization.« less

  14. Phenotypic and genotypic studies of ALS cases in ALS-SMA families.

    PubMed

    Corcia, Philippe; Vourc'h, Patrick; Blasco, Helene; Couratier, Philippe; Dangoumau, Audrey; Bellance, Remi; Desnuelle, Claude; Viader, Fausto; Pautot, Vivien; Millecamps, Stephanie; Bakkouche, Salah; Salachas, FranÇois; Andres, Christian R; Meininger, Vincent; Camu, William

    2018-03-01

    Amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are the most frequent motor neuron disorders in adulthood and infancy, respectively. There is a growing literature supporting common pathophysiological patterns between those disorders. One important clinical issue for that is the co-occurrence of both diseases within a family. To collect families in which ALS and SMA patients co-exist and describe the phenotype and the genotype of ALS patients. Nine families with co-occurrence of SMA and ALS have been gathered over the last 15 years. Epidemiological, phenotype and genetic status were collected. Out of the nine families, six corresponded to the criteria of familial ALS (FALS). Clinical data were available for 11 patients out of the 15 ALS cases. Mean age of onset was 58.5 years, site of onset was lower limbs in nine cases (81.8%), median duration was 22 months. Four ALS patients carried a mutation: three mutations in SOD1 gene (G147N in two cases and one with E121G) and one repeat expansion in the C9ORF72 gene. Three patients had abnormal SMN1 copy numbers. While the high proportion of familial history of ALS cases in these ALS-SMA pedigrees could have suggested that these familial clusters of the two most frequent MND rely on a genetic background, we failed to exclude that this occurred by chance.

  15. Study on Mg/Al Weld Seam Based on Zn–Mg–Al Ternary Alloy

    PubMed Central

    Liu, Liming; Liu, Fei; Zhu, Meili

    2014-01-01

    Based on the idea of alloying welding seams, a series of Zn–xAl filler metals was calculated and designed for joining Mg/Al dissimilar metals by gas tungsten arc (GTA) welding. An infrared thermography system was used to measure the temperature of the welding pool during the welding process to investigate the solidification process. It was found that the mechanical properties of the welded joints were improved with the increasing of the Al content in the Zn–xAl filler metals, and when Zn–30Al was used as the filler metal, the ultimate tensile strength could reach a maximum of 120 MPa. The reason for the average tensile strength of the joint increasing was that the weak zone of the joint using Zn–30Al filler metal was generated primarily by α-Al instead of MgZn2. When Zn–40Al was used as the filler metal, a new transition zone, about 20 μm-wide, appeared in the edge of the fusion zone near the Mg base metal. Due to the transition zones consisting of MgZn2- and Al-based solid solution, the mechanical property of the joints was deteriorated. PMID:28788508

  16. Ohmic contacts to Al-rich AlGaN heterostructures

    SciTech Connect

    Douglas, E. A.; Reza, S.; Sanchez, C.; Koleske, D.; Allerman, A.; Klein, B.; Armstrong, A. M.; Kaplar, R. J.; Baca, A. G.

    2017-06-06

    Due to the ultra-wide bandgap of Al-rich AlGaN, up to 5.8 eV for the structures in this study, obtaining low resistance ohmic contacts is inherently difficult to achieve. A comparative study of three different fabrication schemes is presented for obtaining ohmic contacts to an Al-rich AlGaN channel. Schottky-like behavior was observed for several different planar metallization stacks (and anneal temperatures), in addition to a dry-etch recess metallization contact scheme on Al0.85Ga0.15N/Al0.66Ga0.34N. However, a dry etch recess followed by n+-GaN regrowth fabrication process is reported as a means to obtain lower contact resistivity ohmic contacts on a Al0.85Ga0.15N/Al0.66Ga0.34N heterostructure. In conclusion, specific contact resistivity of 5×10-3 Ω cm2 was achieved after annealing Ti/Al/Ni/Au metallization.

  17. Synthesis of core-shell AlOOH hollow nanospheres by reacting Al nanoparticles with water.

    PubMed

    Lozhkomoev, A S; Glazkova, E A; Bakina, O V; Lerner, M I; Gotman, I; Gutmanas, E Y; Kazantsev, S O; Psakhie, S G

    2016-05-20

    A novel route for the synthesis of boehmite nanospheres with a hollow core and the shell composed of highly crumpled AlOOH nanosheets by oxidizing Al nanopowder in pure water under mild processing conditions is described. The stepwise events of Al transformation into boehmite are followed by monitoring the pH in the reaction medium. A mechanism of formation of hollow AlOOH nanospheres with a well-defined shape and crystallinity is proposed which includes the hydration of the Al oxide passivation layer, local corrosion of metallic Al accompanied by hydrogen evolution, the rupture of the protective layer, the dissolution of Al from the particle interior and the deposition of AlOOH nanosheets on the outer surface. In contrast to previously reported methods of boehmite nanoparticle synthesis, the proposed method is simple, and environmentally friendly and allows the generation of hydrogen gas as a by-product. Due to their high surface area and high, slit-shaped nanoporosity, the synthesized AlOOH nanostructures hold promise for the development of more effective catalysts, adsorbents, vaccines and drug carriers.

  18. Thermal oxidation of the intermetallic phases Al8Mo3 and AlMo3

    NASA Astrophysics Data System (ADS)

    Oster, Michael; Tapp, Joshua; Hagenow, Alexander; Möller, Angela

    2017-07-01

    The thermal oxidation reactions of the intermetallic phases Al8Mo3 and AlMo3 were investigated and analyzed by ex-situ powder-x-ray diffraction (XRD), difference thermal analysis (DTA), thermogravimetry (TGA), and infrared spectroscopy (IR). The initial oxidation reactions in air were found to yield Al2O3 and AlMo3 in the case of Al8Mo3 (Tonset =725 °C), and MoO3 as well as Al8-xMo3 (Tonset =435 °C) for the pure intermetallic phase AlMo3, respectively. Thus, both intermetallic phases are coexisting in an equilibrium within a temperature range of 300 °C under oxidizing conditions. The formation of β-Al2(MoO4)3 followed the second oxidizing process of the respective minority component at elevated temperatures. Decomposition and evaporation of the volatile MoO3 yielded α-Al2O3 as the residue at 1000 °C.

  19. Synthesis of core-shell AlOOH hollow nanospheres by reacting Al nanoparticles with water

    NASA Astrophysics Data System (ADS)

    Lozhkomoev, A. S.; Glazkova, E. A.; Bakina, O. V.; Lerner, M. I.; Gotman, I.; Gutmanas, E. Y.; Kazantsev, S. O.; Psakhie, S. G.

    2016-05-01

    A novel route for the synthesis of boehmite nanospheres with a hollow core and the shell composed of highly crumpled AlOOH nanosheets by oxidizing Al nanopowder in pure water under mild processing conditions is described. The stepwise events of Al transformation into boehmite are followed by monitoring the pH in the reaction medium. A mechanism of formation of hollow AlOOH nanospheres with a well-defined shape and crystallinity is proposed which includes the hydration of the Al oxide passivation layer, local corrosion of metallic Al accompanied by hydrogen evolution, the rupture of the protective layer, the dissolution of Al from the particle interior and the deposition of AlOOH nanosheets on the outer surface. In contrast to previously reported methods of boehmite nanoparticle synthesis, the proposed method is simple, and environmentally friendly and allows the generation of hydrogen gas as a by-product. Due to their high surface area and high, slit-shaped nanoporosity, the synthesized AlOOH nanostructures hold promise for the development of more effective catalysts, adsorbents, vaccines and drug carriers.

  20. High temperature deformation of NiAl and CoAl

    NASA Technical Reports Server (NTRS)

    Nix, W. D.

    1982-01-01

    The high temperature mechanical properties of the aluminides are reviewed with respect to their potential as high temperature structural materials. It is shown that NiAl and CoAl are substantially stronger than the pure metals Ni and Co at high temperatures and approach the strength of some superalloys, particularly when those superalloys are tested in "weak" directions. The factors that limit and control the high temperature strengths of NiAl and CoAl are examined to provide a basis for the development of intermetallic alloys of this type.

  1. [Al species distribution of organic silicate aluminum hybrid flocculants by Al-ferron complexation timed spectrophotometric method].

    PubMed

    Peng, Jian-xiong; Xue, An; Zhao, Hua-zhang; Du, Lian-ying

    2008-09-01

    New types of organic silicate aluminum hybrid flocculants were prepared by employing Tetraethylorthosilicat (TEOS), Diethoxydimethylsilane (DEDMS), gamma-Aminopropylmethyldiethoxysilane (APDES) as silicon source. The Al species distribution in these new products was investigated by Al-Ferron complexation timed spectrophotometric method. The results show that silicon source, basicity (B) and Si/Al molar ratio have effect on the Al species distribution. Among them, basicity has greater effect, three sets of products have similar characteristics. The content of Al(a) declines with the rise of B value, while the contents of Al(b) and Al(c) increase. Al(c) is the dominant Al species in the products with TEOS as silicon source. DEDMS has little contribution to the distribution of Al species. In the products with APDES as silicon source, Al(c) is the dominant Al species while the content increases with the rise of Si/Al molar ratio.

  2. Characterization of N-polar AlN in GaN/AlN/(Al,Ga)N heterostructures grown by metal-organic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Li, Haoran; Mazumder, Baishakhi; Bonef, Bastien; Keller, Stacia; Wienecke, Steven; Speck, James S.; Denbaars, Steven P.; Mishra, Umesh K.

    2017-11-01

    In GaN/(Al,Ga)N high-electron-mobility transistors (HEMT), AlN interlayer between GaN channel and AlGaN barrier suppresses alloy scattering and significantly improves the electron mobility of the two-dimensional electron gas. While high concentrations of gallium were previously observed in Al-polar AlN interlayers grown by metal-organic chemical vapor deposition, the N-polar AlN (Al x Ga1‑x N) films examined by atom probe tomography in this study exhibited aluminum compositions (x) equal to or higher than 95% over a wide range of growth conditions. The also investigated AlN interlayer in a N-polar GaN/AlN/AlGaN/ S.I. GaN HEMT structure possessed a similarly high x content.

  3. Partitioning of iron to Zr/sub 2/Al during the peritectoid transformation Zr + Zr/sub 2/Al. -->. Zr/sub 3/Al

    SciTech Connect

    Schulson, E.M.; Davidson, R.D.

    1977-12-01

    A study of the peritectoid transformation Zr + Zr/sub 2/Al ..-->.. Zr/sub 3/Al was made. Zr/sub 2/Al particles act as iron sinks similar to hydrogen sinks. The system is a three component alloy, and is thermodynamically stable over a range of temperatures accounting for Zr/sub 2/Al even in the hypostoichiometric alloy. The smaller the amount of iron in the starting material, the samller the amount of residual Zr/sub 2/Al. (FS)

  4. ALS and FTD: an epigenetic perspective.

    PubMed

    Belzil, Veronique V; Katzman, Rebecca B; Petrucelli, Leonard

    2016-10-01

    Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two fatal neurodegenerative diseases seen in comorbidity in up to 50 % of cases. Despite tremendous efforts over the last two decades, no biomarkers or effective therapeutics have been identified to prevent, decelerate, or stop neuronal death in patients. While the identification of multiple mutations in more than two dozen genes elucidated the involvement of several mechanisms in the pathogenesis of both diseases, identifying the hexanucleotide repeat expansion in C9orf72, the most common genetic abnormality in ALS and FTD, opened the door to the discovery of several novel pathogenic biological routes, including chromatin remodeling and transcriptome alteration. Epigenetic processes regulate DNA replication and repair, RNA transcription, and chromatin conformation, which in turn further dictate transcriptional regulation and protein translation. Transcriptional and post-transcriptional epigenetic regulation is mediated by enzymes and chromatin-modifying complexes that control DNA methylation, histone modifications, and RNA editing. While the alteration of DNA methylation and histone modification has recently been reported in ALS and FTD, the assessment of epigenetic involvement in both diseases is still at an early stage, and the involvement of multiple epigenetic players still needs to be evaluated. As the epigenome serves as a way to alter genetic information not only during aging, but also following environmental signals, epigenetic mechanisms might play a central role in initiating ALS and FTD, especially for sporadic cases. Here, we provide a review of what is currently known about altered epigenetic processes in both ALS and FTD and discuss potential therapeutic strategies targeting epigenetic mechanisms. As approximately 85 % of ALS and FTD cases are still genetically unexplained, epigenetic therapeutics explored for other diseases might represent a profitable direction for the

  5. Fabrication of Al-Al3Ti/Ti3Al Functionally Graded Materials under a Centrifugal Force

    PubMed Central

    El-Hadad, Shimaa; Sato, Hisashi; Miura-Fujiwara, Eri; Watanabe, Yoshimi

    2010-01-01

    Fabrication of Al-Al3Ti functionally graded materials (FGMs) under the centrifugal force has recently attracted some attention. The controlled compositional gradient of the fabricated FGMs, the low cost of the process, and the good mold filling, are the main advantages of the centrifugal method (CM). Using the conventional CM techniques such as the centrifugal solid-particle method and centrifugal in-situ method, FGMs rings with gradually distributed properties could be achieved. As a more practical choice, the centrifugal mixed-powder method (CMPM) was recently proposed to obtain FGMs containing nano-particles selectively dispersed in the outer surface of the fabricated parts. However, if a control of the particles morphology, compound formulas or sizes, is desired, another CM technique is favored. As a development of CMPM, our novel reaction centrifugal mixed-powder method (RCMPM) has been presented. Using RCMPM, Al‑Al3Ti/Ti3Al FGMs with good surface properties and temperature controlled compositional gradient could be achieved. In this short review, this novel method will be discussed in detail and the effect of RCMPM processing temperature on the reinforcement particles morphology, size and distribution through the fabricated samples, will be reviewed. PMID:28883345

  6. Hypermetabolism as a Risk Factor for ALS

    DTIC Science & Technology

    2012-07-01

    Linked to Obesity , and Alters Body Fat Metabolism. Proc Natl Acad Sci U S A, online Jul 26, 2010. 2. Chadt A, et al: Tbc1d1 mutation in lean ...mouse strain confers leanness and protects from diet-induced obesity . Nat Genet 40(11):1354-1359, 2008. 3. Stone S, et al: TBC1D1 is a candidate...promise for development of new therapies. Our recent discovery in mice that lack Tdp-43 showed that these mice excessively burned out their body fat

  7. Distribution and size of lava shields on the Al Haruj al Aswad and the Al Haruj al Abyad Volcanic Systems, Central Libya

    NASA Astrophysics Data System (ADS)

    Elshaafi, Abdelsalam; Gudmundsson, Agust

    2017-05-01

    The Al Haruj Volcanic Province (AHVP) consists of two distinct volcanic systems. In the north is the system of Al Haruj al Aswad, covering an area of 34,200 km2, while in the south the system of Al Haruj al Abyad, covering an area of 7,850 km2. The systems have produced some 432 monogenetic volcanoes, primarily scoria (cinder) cones, lava shields, and maars. The density distribution of the volcanoes in each system, plotted as eruption points or sites, has a roughly elliptical surface expression, suggesting similar plan-view geometry of the magma sources, here suggested as deep-seated reservoirs. More specifically, the Al Haruj al Aswad magma reservoir has major and minor axes of 210 km and 119 km, respectively, and an area of 19,176 km2, the corresponding figures for the Haruj al Abyad reservoir being 108 km and 74 km, for the axes, and 6209 km2 for the area. We measured 55 lava shields on the AHVP. They are mostly restricted to the northern and southern parts of AHVP and date from late Miocene to (at least) the end of Pleistocene, while some may have been active into Holocene. In fact, although primarily monogenetic, some of the lava shields show evidence of (possibly Holocene) fissure eruptions in the summit parts. The early lava shields tend to be located at the edges of volcanic systems and with greater volumes than later (more central) shields. The average lava shield basal diameter is 4.5 km and height 63 m. There is strong linear correlation between lava shield volume and basal area, the coefficient of determination (R2) being about 0.75. When 22 Holocene Icelandic lava shields are added to the dataset, for comparison, the correlation between volume and basal area becomes R2 = 0.95. Numerical models suggest that the local stress fields favoured rupture and dyke injection at the margins of the source reservoirs during late Miocene - early Pliocene, in agreement with the distribution of the early, large-volume shields.

  8. Complementary and Alternative Therapies in ALS

    PubMed Central

    Bedlack, Richard S.; Joyce, Nanette; Carter, Gregory T.; Pagononi, Sabrina; Karam, Chafic

    2015-01-01

    Synopsis Given the severity of their illness and lack of effective disease modifying agents, it is not surprising that most patients with ALS consider trying complementary and alternative therapies. Some of the most commonly considered alternative therapies include special diets, nutritional supplements, cannabis, acupuncture, chelation and energy healing. This chapter reviews these in detail. We also describe 3 models by which physicians may frame discussions about alternative therapies: paternalism, autonomy and shared decision making. Finally, we review a program called ALSUntangled which using shared shared decision making to review alternative therapies for ALS. PMID:26515629

  9. The Genyornis Egg: Response to Miller et al.'s commentary on Grellet-Tinner et al., 2016

    NASA Astrophysics Data System (ADS)

    Grellet-Tinner, Gerald; Spooner, Nigel A.; Handley, Warren D.; Worthy, Trevor H.

    2017-04-01

    Williams (1981) and Williams and Rich (1991) attributed Australian Quaternary fossil eggshell that differed from that of emu Dromaius novaehollandiae to the extinct bird Genyornis newtoni without any osteological or embryonic support. Such association by proximity or abundance mirrors the case of the mistaken association of oviraptor eggs to Protoceratops in the 1920's by Andrews (Grellet-Tinner and Makovicky, 2006). No other candidate species was considered, and this attribution has been unchallenged and followed by everyone thereafter. Much research has been done on this Australian eggshell, with one result being that the extinction of the parent of this eggshell is the most well documented for a taxon in Australia (e.g., Miller et al., 1999, 2005). Grellet-Tinner et al. (2016) raised several problems with the identity of the eggshell Williams (1981) attributed to Genyornis newtoni and suggested that extinct megapodes of the genus Progura were the more likely layer of this eggshell type, therein referred to as ;putative Genyornis oological material; (PGOM). Miller et al. (2017) challenged our hypothesis stating that ;Based on the dimensions of the reconstructed Spooner Egg,Grellet-Tinner et al. (2016)argue that PGOM is too small for a bird with the body mass estimated for Genyornis (168-275 kg) … …[and] …. None of the additional PGOM observations reported byGrellet-Tinner et al. (2016)are inconsistent with a Genyornis parent;. Here we take the opportunity to respond to their critique, the basis of which resolves into a few points, which we address in turn.

  10. Electronic circuits having NiAl and Ni.sub.3 Al substrates

    DOEpatents

    Deevi, Seetharama C.; Sikka, Vinod K.

    1999-01-01

    An electronic circuit component having improved mechanical properties and thermal conductivity comprises NiAl and/or Ni.sub.3 Al, upon which an alumina layer is formed prior to applying the conductive elements. Additional layers of copper-aluminum alloy or copper further improve mechanical strength and thermal conductivity.

  11. Directional Solidification and Mechanical Properties of NiAl-NiAlTa Alloys

    NASA Technical Reports Server (NTRS)

    Johnson, D. R.; Chen, X. F.; Oliver, B. F.; Noebe, R. D.; Whittenberger, J. D.

    1995-01-01

    Directional solidification of eutectic alloys is a promising technique for producing in-situ composite materials exhibiting a balance of properties. Consequently, the microstructure, creep strength and fracture toughness of directionally solidified NiAl-NiAlTa alloys were investigated. Directional solidification was performed by containerless processing techniques to minimize alloy contamination. The eutectic composition was found to be NiAl-15.5 at% Ta and well-aligned microstructures were produced at this composition. A near-eutectic alloy of NiAl-14.5Ta was also investigated. Directional solidification of the near-eutectic composition resulted in microstructures consisting of NiAl dendrites surrounded by aligned eutectic regions. The off-eutectic alloy exhibited promising compressive creep strengths compared to other NiAl-based intermetallics, while preliminary testing indicated that the eutectic alloy was competitive with Ni-base single crystal superalloys. The room temperature toughness of these two-phase alloys was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa.

  12. Burden of rare variants in ALS genes influences survival in familial and sporadic ALS.

    PubMed

    Pang, Shirley Yin-Yu; Hsu, Jacob Shujui; Teo, Kay-Cheong; Li, Yan; Kung, Michelle H W; Cheah, Kathryn S E; Chan, Danny; Cheung, Kenneth M C; Li, Miaoxin; Sham, Pak-Chung; Ho, Shu-Leong

    2017-10-01

    Genetic variants are implicated in the development of amyotrophic lateral sclerosis (ALS), but it is unclear whether the burden of rare variants in ALS genes has an effect on survival. We performed whole genome sequencing on 8 familial ALS (FALS) patients with superoxide dismutase 1 (SOD1) mutation and whole exome sequencing on 46 sporadic ALS (SALS) patients living in Hong Kong and found that 67% had at least 1 rare variant in the exons of 40 ALS genes; 22% had 2 or more. Patients with 2 or more rare variants had lower probability of survival than patients with 0 or 1 variant (p = 0.001). After adjusting for other factors, each additional rare variant increased the risk of respiratory failure or death by 60% (p = 0.0098). The presence of the rare variant was associated with the risk of ALS (Odds ratio 1.91, 95% confidence interval 1.03-3.61, p = 0.03), and ALS patients had higher rare variant burden than controls (MB, p = 0.004). Our findings support an oligogenic basis with the burden of rare variants affecting the development and survival of ALS. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  13. NEK1 genetic variability in a Belgian cohort of ALS and ALS-FTD patients.

    PubMed

    Nguyen, Hung Phuoc; Van Mossevelde, Sara; Dillen, Lubina; De Bleecker, Jan L; Moisse, Matthieu; Van Damme, Philip; Van Broeckhoven, Christine; van der Zee, Julie

    2018-01-01

    We evaluated the genetic impact of the amyotrophic lateral sclerosis (ALS) risk gene never in mitosis gene a-related kinase 1 (NEK1) in a Belgian cohort of 278 patients with ALS (n = 245) or ALS with frontotemporal dementia (ALS-FTD, n = 33) and 609 control individuals. We identified 2 ALS patients carrying a loss-of-function (LOF) mutation, p.Leu854Tyrfs*2 and p.Tyr871Valfs*17, that was absent in the control group. A third LOF variant p.Ser1036* was present in 2 sibs with familial ALS but also in an unrelated control person. Missense variants were common in both patients (3.6%) and controls (3.0%). The missense variant, p.Arg261His, which was previously associated with ALS risk, was detected with a minor allele frequency of 0.90% in patients compared to 0.33% in controls. Taken together, NEK1 LOF variants accounted for 1.1% of patients, although interpretation of pathogenicity and penetrance is complicated by the observation of occasional LOF variants in unaffected individuals (0.16%). Furthermore, enrichment of additional ALS gene mutations was observed in NEK1 carriers, suggestive of a "second hit" model were NEK1 variants may modify disease presentation of driving mutations. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  14. Al Qaeda in the Arabian Peninsula (AQAP): An Al Qaeda Affiliate Case Study

    DTIC Science & Technology

    2017-10-01

    Also, Al-Qaeda’s attacks on Westerners alienated the civilian population. In April 2005, a group of the remaining Al-Qaeda leaders were killed. By...AQAP had shown some “moderation” vis-à-vis the Houthis so as not to alienate ordinary Yemeni Sunni Muslims who had no grievances toward the Houthis

  15. An Alternative Perspective on von Winterfeldt et al.'s (1997) Test of Consequence Monotonicity

    ERIC Educational Resources Information Center

    Ho, Moon-Ho R.; Regenwetter, Michel; Niederee, Reinhard; Heyer, Dieter

    2005-01-01

    D. von Winterfeldt, N.-K. Chung, R. D. Luce, and Y. Cho (see record 1997-03378-008) provided several tests for consequence monotonicity of choice or judgment, using certainty equivalents of gambles. The authors reaxiomatized consequence monotonicity in a probabilistic framework and reanalyzed von Winterfeldt et al.'s main experiment via a…

  16. Melting, Processing, and Properties of Disordered Fe-Al and Fe-Al-C Based Alloys

    NASA Astrophysics Data System (ADS)

    Satya Prasad, V. V.; Khaple, Shivkumar; Baligidad, R. G.

    2014-09-01

    This article presents a part of the research work conducted in our laboratory to develop lightweight steels based on Fe-Al alloys containing 7 wt.% and 9 wt.% aluminum for construction of advanced lightweight ground transportation systems, such as automotive vehicles and heavy-haul truck, and for civil engineering construction, such as bridges, tunnels, and buildings. The melting and casting of sound, porosity-free ingots of Fe-Al-based alloys was accomplished by a newly developed cost-effective technique. The technique consists of using a special flux cover and proprietary charging schedule during air induction melting. These alloys were also produced using a vacuum induction melting (VIM) process for comparison purposes. The effect of aluminum (7 wt.% and 9 wt.%) on melting, processing, and properties of disordered solid solution Fe-Al alloys has been studied in detail. Fe-7 wt.% Al alloy could be produced using air induction melting with a flux cover with the properties comparable to the alloy produced through the VIM route. This material could be further processed through hot and cold working to produce sheets and thin foils. The cold-rolled and annealed sheet exhibited excellent room-temperature ductility. The role of carbon in Fe-7 wt.% Al alloys has also been examined. The results indicate that Fe-Al and Fe-Al-C alloys containing about 7 wt.% Al are potential lightweight steels.

  17. CVD Fiber Coatings for Al2O3/NiAl Composites

    NASA Technical Reports Server (NTRS)

    Boss, Daniel E.

    1995-01-01

    While sapphire-fiber-reinforced nickel aluminide (Al2O3/NiAl) composites are an attractive candidate for high-temperature structures, the significant difference in the coefficient of thermal expansion between the NiAl matrix and the sapphire fiber creates substantial residual stresses in the composite. This study seeks to produce two fiber-coating systems with the potential to reduce the residual stresses in the sapphire/NiAl composite system. Chemical vapor deposition (CVD) was used to produce both the compensating and compliant-fiber coatings for use in sapphire/NiAl composites. A special reactor was designed and built to produce the FGM and to handle the toxic nickel precursors. This process was successfully used to produce 500-foot lengths of fiber with coating thicknesses of approximately 3 microns, 5 microns, and 10 microns.

  18. A reply to King et al

    Treesearch

    Mark E. Swanson; Jerry F. Franklin; Robert L. Beschta; Charles M. Crisafulli; Dominick A. DellaSala; Richard Hutto; David Lindenmayer; Frederick J. Swanson

    2011-01-01

    King et al are correct in their assessment of an increase in research and management interest in early successional stages after disturbance. But their claim that “... the conservation status of species that depend on early successional forest is now widely appreciated by natural resource management agencies” merits further reflection. Etc.

  19. U-ALS: A Ubiquitous Learning Environment

    ERIC Educational Resources Information Center

    Piovesan, Sandra Dutra; Passerino, Liliana Maria; Medina, Roseclea Duarte

    2012-01-01

    The diffusion of the use of the learning virtual environments presents a great potential for the development of an application which meet the necessities in the education area. In view of the importance of a more dynamic application and that can adapt itself continuously to the students' necessities, the "U-ALS" (Ubiquitous Adapted Learning…

  20. Correction to Rothermund et al. (2005)

    ERIC Educational Resources Information Center

    Rothermund, Klaus; Wentura, Dirk; De Houwer, Jan

    2005-01-01

    This article reports an error in the article "Retrieval of Incidental Stimulus-Response Associations as a Source of Negative Priming" by Rothermund et al. ("Journal of Experimental Psychology: Learning, Memory, and Cognition," Vol 31(3) May 2005, 482-495). Table 1 (p. 484) was incorrectly typeset. The correct layout is provided. (The following…

  1. Cryptanalysis on Cheng et al. protocol

    NASA Astrophysics Data System (ADS)

    Thakur, Tejeshwari

    2016-06-01

    Deployment of new node in any wireless sensor network is a sensitive task. This is the reason why, an Access Control Protocol is required in WSN. In this paper, we demonstrate that Access Control Protocol proposed by Cheng et al.[1] for Wireless Sensor Network is insecure. The reason is that this protocol fails to resist the active attack.

  2. Kinematics of Disease Progression in Bulbar ALS

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne

    2010-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…

  3. Bierman {ital et al.}Reply:

    SciTech Connect

    Bierman, J.D.; Chan, P.; Liang, J.F.

    1997-05-01

    reply to the Comment by C.H.Dasso et al., Phys. Rev. Lett. 78,XXX(1997). A Reply to the Comment by C.H. Dasso and J. Fern{acute a}ndez-Niello. {copyright} {ital 1997} {ital The American Physical Society}

  4. Everyday Life with ALS: A Practical Guide

    MedlinePlus

    ... you face everyday life with ALS. Your entire team will work with you to ensure that you remain as ... select- ing a power chair, it’s wise to work with a qualified expert — or even a team of experts — to find the chair that best ...

  5. Kinematics of disease progression in bulbar ALS.

    PubMed

    Yunusova, Yana; Green, Jordan R; Lindstrom, Mary J; Ball, Laura J; Pattee, Gary L; Zinman, Lorne

    2010-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech performance such as speaking rate and speech intelligibility. Movements of the lip and jaw were quantified with respect to their size speed, and duration. The data revealed several changes in lip and jaw movement that coincided with ALS progression. In two out of three speakers, the changes in measures of path distance and speed anticipated the drop in speech intelligibility by approximately 3 months. With disease progression, increases in movement duration coincided with declines in speech intelligibility. Overall, the movement measures appeared to be sensitive to disease progression in ALS. By the end of the manuscript, the reader should be able to: (1) describe the changes that occur in articulatory movements of the jaw and lower lip in ALS; (2) understand the relationship between physiologic measures of movement and speech intelligibility and speaking rate; (3) identify critical points in the disease progression and understand which quantitative measures reveal the state of the bulbar system at these time points. (c) 2009 Elsevier Inc. All rights reserved.

  6. Kinematics of Disease Progression in Bulbar ALS

    PubMed Central

    Yunusova, Yana; Green, Jordan; Lindstrom, Mary; Ball, Laura; Pattee, Gary; Zinman, Lorne

    2009-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar Amyotrophic Lateral Sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech performance such as speaking rate and speech intelligibility. Movements of the lip and jaw were quantified with respect to their size (i.e., path distance measure), speed, and duration. The data revealed several changes in lip and jaw movement that coincided with ALS progression. In two out of three speakers, the changes in measures of path distance and speed anticipated the drop in speech intelligibility by approximately 3 months. With disease progression, increases in movement duration coincided with declines in speech intelligibility. Overall, the movement measures appeared to be sensitive to disease progression in ALS. Learning outcomes By the end of the manuscript, the reader should be able to: (1) describe the changes that occur in articulatory movements of the jaw and lower lip in ALS; (2) understand the relationship between physiologic measures of movement and speech intelligibility and speaking rate; (3) identify critical points in the disease progression and understand which quantitative measures reveal the state of the bulbar system at these time points. PMID:19683250

  7. Ibn al-Haytham and psychophysics.

    PubMed

    Aaen-Stockdale, Craig

    2008-01-01

    Persian scholar Ibn al-Haytham ('Alhazen') has rightly been credited with many advances in optics and vision science, but recent spurious claims that he is the 'founder of psychophysics' rest upon unsupported assertions, a conflation of psychophysics with the wider discipline of psychology, and semantic arguments over what it is to 'found' a school of thought.

  8. Joint SSRTNet/ALS-MES Workshop report

    SciTech Connect

    Shuh, David; Van Hove, Michel

    2001-11-30

    This joint workshop brought together experimentalists and theorists interested in synchrotron radiation and highlighted subjects relevant to molecular environmental science (MES). The strong mutual interest between the participants resulted in joint sessions on the first day, followed by more specialized parallel sessions on the second day. Held in conjunction with the Advanced Light Source (ALS) Users' Association Annual Meeting at the Lawrence Berkeley National Laboratory (Berkeley Lab), the Synchrotron Radiation Research Theory Network (SRRTNet) workshop was co-organized by Michel Van Hove (Berkeley Lab and University of California, Davis) and Andrew Canning (Berkeley Lab), while David Shuh (Berkeley Lab) organized themore » ALS-MES workshop. SRRTNet is a global network that promotes the interaction of theory and experiment (http://www.cse.clrc.ac.uk/Activity/SRRTnet). The ALS-MES project is constructing Beamline 11.0.2.1-2, a new soft x-ray beamline for MES investigations at photon energies from 75 eV to 2 keV, to provide photons for wet spectroscopy end stations and an upgraded scanning transmission x-ray microscope (STXM). The ALS-MES beamline and end stations will be available for users in the late fall of 2002.« less

  9. Al-Qaeda Core: A Case Study

    DTIC Science & Technology

    2017-10-01

    shiites- exposes-a-divide-among-sunni-jihadists, accessed March 3, 2017; and “Al-Qaeda Disowns ‘ Fake Letter,” BBC News, October 13, 2005, http...23 Wealthy individuals in the Persian Gulf countries who made up the so-called Golden Chain were major benefactors.24 Since 9/11, anti– money

  10. Hopkins in the A/L

    NASA Image and Video Library

    2013-12-18

    View of Mike Hopkins, Expedition 38 Flight Engineer (FE), during remove and replace (R&R) of Hard Upper Torso (HUT) of Extravehicular Mobility Unit (EMU), in the airlock (A/L) during preparation for EVA-24. Photo was taken during Expedition 38. Image was released by astronaut on Twitter.

  11. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, Jr., Karl A.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant.

  12. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, K.A. Jr.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant. 29 figs.

  13. Data used in Xu et al., 2016

    EPA Pesticide Factsheets

    Mercury emissions data from anthropogenic sources as described in Xu et al., 2016.This dataset is associated with the following publication:Xu, X., N. Liu, M. Landis, X. Feng, and G. Qiu. Characteristics and distributions of atmospheric mercury emitted from anthropogenic sources in Guiyang, southwestern China. Acta Geochimica. Springer, Heidelburg, GERMANY, 1-11, (2016).

  14. Quantum Criticality in YFe2Al10

    NASA Astrophysics Data System (ADS)

    Gannon, William; Wu, Liusuo; Zaliznyak, Igor; Qiu, Yiming; Rodriguez-Rivera, Jose; Aronson, Meigan

    Quantum criticality has been studied in many systems, but there are few systems where observed scaling can be unified with a critical free energy F, or where the critical exponents form the basis for QC universality classes. We have identified a new layered material YFe2Al10 that shows remarkably strong QC behavior, where the scaling properties of the magnetic susceptibility and specific heat are consistent with the same F. Recent neutron scattering results paint a remarkable picture of the QC fluctuations in YFe2Al10. In contrast to classical transitions, where fluctuations are relatively long ranged and inelastic scattering is observed at a magnetic zone center, in YFe2Al10 the scattering is independent of wave vector in the critical plane, indicating that the fluctuations are spatially localized, while out of plane scattering indicates that the interplaner interactions are restricted to nearest neighbors. The dynamical susceptibility χ'' ~=E-2 , and is wholly temperature independent, indicating that E/T scaling is present, the signature of QC fluctuations. These results hint that the the criticality in YFe2Al10 is local, which until now has only been found in a few f-electron based compounds.

  15. Formation of gamma'-Ni3Al via the Peritectoid Reaction: gamma plus beta (+Al2O3) equals gamma'(+Al2O3)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2008-01-01

    The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8 - 32 at.%Al and temperature range T = 1400 - 1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of gamma'-Ni3Al-containing alloys occurs by the eutectic reaction, L (+ Al2O3) = gamma + beta (+ Al2O3), at 1640 plus or minus 1 K and a liquid composition of 24.8 plus or minus 0.2 at.%Al (at an unknown oxygen content). The {gamma + beta + Al2O3} phase field is stable over the temperature range 1633 - 1640 K, and gamma'-Ni3Al forms via the peritectiod, gamma + beta (+ Al2O3) = gamma'(+ Al2O3), at 1633 plus or minus 1 K. This behavior is inconsistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma'-Ni3Al phase field.

  16. Formation of gamma(sup prime)-Ni3Al via the Peritectoid Reaction: gamma + beta (+ Al2O3)=gamma(sup prime)(+ Al2O3)

    NASA Technical Reports Server (NTRS)

    Copeland, Evan

    2008-01-01

    The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8-32 at.%Al and temperature range T=1400-1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of gamma(sup prime)-Ni3Al-containing alloys occurs by the eutectic reaction, L (+ Al2O3)=gamma + Beta(+ Al2O3), at 1640 +/- 1 K and a liquid composition of 24.8 +/- 0.2 at.%al (at an unknown oxygen content). The {gamma + Beta (+Al2O3} phase field is stable over the temperature range 1633-1640 K, and gamma(sup prime)-Ni3Al forms via the peritectoid, gamma + Beta (+ Al2O3)=gamma(sup prime) (+ Al2O3), at 1633 +/- 1 K. This behavior is consistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady-state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma(sup prime)-Ni2Al phase field.

  17. Hydrogen Solubility in Al-bearing Perovskite

    NASA Astrophysics Data System (ADS)

    Watson, H. C.; Krawczynski, M. J.; Fei, Y.

    2005-12-01

    It is generally accepted that silicate perovskite is the dominant mineral in the Earth's lower mantle. Previous studies have been completed to determine the physical and chemical characteristics of the pure end-member MgSiO3. Recent studies have shown that the addition of Al to MgSiO3 can have a significant effect on the material properties of the mineral, such as compressibility, and defect structure, as well as a great potential to dissolve water. We have synthesized Al-bearing perovskite samples under hydrous conditions in a multi-anvil apparatus at pressures ranging from 23-26 GPa and 1800oC. The starting materials consisted of brucite and silica powders mixed together and finely ground in a 1:1 molar ratio, with subsequent addition of Al2O3 powder at 2wt% intervals from 0%-6%. The mixed powders were tightly packed in Au capsules, housed in BN sleeves, and loaded into standard 8/3 multi-anvil assemblies. The experiments were brought to the appropriate pressure conditions for solubility of the different Al2O3 contents. The resulting perovskite crystals range in size from <20 microns to >100 microns in size. Their major element chemistry has been characterized by EPMA, and the H content of some samples has been measured by secondary ion mass spectrometry using a 6f Cameca ion microprobe and is substantial (>1200ppm in some samples). In this study, we correlate H content in the perovskites with Al concentration, and discussion follows on what effects this may have on potential substitution mechanisms, and correlated formation of oxygen vacancies, as well as water storage in the mantle, oxygen diffusion, and the potential of an oxygen ionic diffusion contribution to electrical conductivity in the mantle.

  18. Accuracy of Conventional MRI in ALS.

    PubMed

    Gupta, Aparna; Nguyen, Thanh Binh; Chakraborty, Santanu; Bourque, Pierre R

    2014-01-01

    There is currently no definite neuroimaging test to detect amyotrophic lateral sclerosis (ALS), which leads to significant delay in diagnosis, particularly if one takes into account the rapidity of disease evolution. Hyperintensity of the corticospinal tracts (CST) on T2 or fluid-attenuated inversion recovery (FLAIR) weighted magnetic resonance imaging (MRI) has been well described, but data on sensitivity and specificity in larger series is lacking to help guide its application to clinical care. We analyzed clinical and MRI data from 64 patients with a definite retrospective diagnosis of ALS. In this case-control study, two experienced blinded neuroradiologists systematically assessed defined rostrocaudal segments of the intracranial course of the CST. The overall sensitivity and specificity of conventional MRI for the diagnosis of ALS were 48% and 76% respectively. Highest specificities for CST hyperintensity were noted for the subcortical white matter (92%), centrum semiovale (88%) and medullary pyramids (92%). The lowest specificities were found for the cerebral peduncle (36%) and internal capsule (32%). We did not find a correlation with the rate of clinical progression, age of onset or the presence of upper motor neuron signs on examination. Conventional MRI was not found to be a reliable diagnostic tool for ALS and it did not help predict clinical characteristics such as speed of evolution or prominence of upper motor neuron signs. Its main role in the setting of ALS should remain to help exclude alternative diagnostic considerations. A multimodal approach relying on newer functional and structural MRI techniques still needs to be developed and validated. Précision de l'IRM conventionnelle dans la SLA.

  19. Hydride formation in mechanically alloyed Al-Zr and Al-Fe-Zr

    SciTech Connect

    Niu, X.P.; Froyen, L.; Delaey, L.

    1994-01-01

    The present work deals with the formation of hydride during MA of Al alloys with addition of Zr. The effect of hydride formation on the degassing as well as on the mechanical properties are also investigated. It is well known that Zr is able to bind considerable quantities of hydrogen by forming hydrides. Depending on the concentration of hydrogen, the composition of Zr-hydrides varies from ZrH to ZrH[sub 2]. The reaction of hydrogen with Zr has been extensively studied because of its technical importance in the nuclear industry. It is believed that the formation of hydride is the main reasonmore » causing embrittlement in Zr and Zr-alloys. Very few studies report the formation of hydrides in Zr-containing Al alloys. Zr in Al alloys can be used either as a grain refiner or as a second phase in the form of aluminide, Al[sub 3]Zr to strengthen Al alloys. Recently, it was reported that the hydrogen gas in powder metallurgical prepared Al alloys can be fixed in the form of hydrides by additions of some hydride-forming elements. As a result, a degassing treatment is no more needed and the fatigue strength can be improved at the same time. Details on the identification of those hydrides in Al alloys are not yet available.« less

  20. A novel Al matrix composite reinforced by nano-AlNpnetwork.

    PubMed

    Ma, X; Zhao, Y F; Tian, W J; Qian, Z; Chen, H W; Wu, Y Y; Liu, X F

    2016-10-10

    In pursuit of lightweighting of automobiles and low emission of transportation, the efforts to develop high-strength, heat-resistant and fatigue-resistant Al alloys and/or composites have been ongoing. Here we report a novel Al matrix composite with ultrahigh strength reinforced by a three dimensional network of nano-AlN particles for the first time. The in-situ synthesized AlN particles are connected by twinning bonding chains and built up a three dimensional network strengthening Al matrix enormously like the skeleton to human body. The composite containing 16.4wt.% AlN particles shows excellent properties: the ultimate tensile strengths can be up to 518MPa at room temperature and 190MPa at 350 °C. This peculiar performance results from the novel spatial distribution of nano-scale AlN particles. Our findings in this work would help to develop a potential candidate for high-performance heat resistance light-metal based materials.

  1. A novel Al matrix composite reinforced by nano-AlNp network

    NASA Astrophysics Data System (ADS)

    Ma, X.; Zhao, Y. F.; Tian, W. J.; Qian, Z.; Chen, H. W.; Wu, Y. Y.; Liu, X. F.

    2016-10-01

    In pursuit of lightweighting of automobiles and low emission of transportation, the efforts to develop high-strength, heat-resistant and fatigue-resistant Al alloys and/or composites have been ongoing. Here we report a novel Al matrix composite with ultrahigh strength reinforced by a three dimensional network of nano-AlN particles for the first time. The in-situ synthesized AlN particles are connected by twinning bonding chains and built up a three dimensional network strengthening Al matrix enormously like the skeleton to human body. The composite containing 16.4wt.% AlN particles shows excellent properties: the ultimate tensile strengths can be up to 518MPa at room temperature and 190MPa at 350 °C. This peculiar performance results from the novel spatial distribution of nano-scale AlN particles. Our findings in this work would help to develop a potential candidate for high-performance heat resistance light-metal based materials.

  2. Ti doped amorphous carbon (Al/Ti-a:C/p-Si/Al) photodiodes for optoelectronic applications

    NASA Astrophysics Data System (ADS)

    Aslan, Naim; Koç, Mümin Mehmet; Dere, Ayşegül; Arif, Bilal; Erkovan, Mustafa; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, Fahrettin

    2018-03-01

    Electrochemical deposition technique was used to fabricate titanium doped amorphous carbon (Ti doped a:C) Al/Ti-a:C/p-Si/Al photodiode. The effects of illumination on the current-voltage (I-V) characteristics of the Al/a:C/p-Si/Al doped Ti diode for optoelectronic applications were investigated. The reverse current of the diode increased with the increasing illumination intensities when the bias voltage was applied. By using the forward bias I-V characteristics, the ideality factor (n) and barrier height (Φb) of Al/Ti-a:C/p-Si photodiode structure was found as 1,84 and 0,50 eV, respectively. In addition, the capacitance-voltage (C-V) and conductance-voltage (G-V) measurements of the diode were studied in the frequency range of 100 kHz-600 kHz. The measured values of the capacitance decreased with the increasing frequency. The photoelectrical properties of Al/Ti-a:C/p-Si/Al device indicates that the photodiode investigated in this paper has great potential to be used in optoelectronic device applications and in industry.

  3. Sub 250 nm deep-UV AlGaN/AlN distributed Bragg reflectors

    NASA Astrophysics Data System (ADS)

    Detchprohm, Theeradetch; Liu, Yuh-Shiuan; Mehta, Karan; Wang, Shuo; Xie, Hongen; Kao, Tsung-Ting; Shen, Shyh-Chiang; Yoder, Paul D.; Ponce, Fernando A.; Dupuis, Russell D.

    2017-01-01

    Deep-UV distributed Bragg reflectors (DBRs) operating at λ = 220-250 nm with reflectivity close to unity were produced using epitaxial AlxGa1-xN/AlN superlattice structures grown on AlN/sapphire templates via metalorganic chemical vapor deposition. Owing to the near-bandedge excitonic resonance in the AlxGa1-xN layers, the AlN mole fractions, x, were regulated to keep the reflective plateau within the enhanced refractive index contrast region between AlGaN and AlN of approximately 7%-11%. For DBRs incorporating high-index layers of AlGaN grown via a flow-rate modulated epitaxy technique, a reflectivity of 97% was achieved with a total pair number of 30.5 which was much smaller than number of pairs needed for the DBRs with conventionally grown AlGaN layers. The stopbands of these DBRs were about 6-9 nm.

  4. Some TEM observations of Al2O3 scales formed on NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, J.; Gibala, R.

    1979-01-01

    The microstructural development of Al2O3 scales on NiCrAl alloys has been examined by transmission electron microscopy. Voids were observed within grains in scales formed on a pure NiCrAl alloy. Both voids and oxide grains grew measurably with oxidation time at 1100 C. The size and amount of porosity decreased towards the oxide-metal growth interface. The voids resulted from an excess number of oxygen vacancies near the oxidemetal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidation of pure, Y-doped, and Zr-doped NiCrAl was also examined. Oriented alpha-(Al, Cr)2O3 and Ni(Al, Cr)2O4 scales often coexisted in layered structures on all three alloys. Close-packed oxygen planes and directions in the corundum and spinel layers were parallel. The close relationship between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.

  5. An epidemiological study of cutaneous leishmaniasis in Al-jabal Al-gharbi, Libya.

    PubMed

    Abdellatif, Manal Z M; El-Mabrouk, Khamis; Ewis, Ashraf A

    2013-02-01

    Cutaneous leishmaniasis (CL) is an endemic parasitic infection in the Mediterranean region, including Libya and its Al-jabal Al-gharbi province. We aimed at studying the occupational relevance as well as other epidemiological aspects of CL. We investigated 140 CL cases who attended at Gharyan outpatient polyclinic during a period of 6 months in 2009. CL infection was clinically diagnosed and confirmed by demonstration of Leishmania parasites on smears from lesions. Our findings showed that males were more affected than females (P=0.04), and people above 10-years were more affected than younger ones (P=0.0001). A significant percent of CL cases belonged to Al-Kawasem subprovince (P=0.0001). Farm-related activities were the most frequent occupations among CL cases (P=0.04). In addition to farm workers, housewives and students are at risk groups since they are engaged at farm activities. Moreover, those who have occupations that require staying outdoors for a part of night, e.g., policemen, are also at risk. Compared to children, adult CL patients had multiple lesions (P=0.001) that were more prevalent in their upper and lower extremities than the face (P=0.0001). We conclude that CL is a major health problem in Al-jabal Al-gharbi province of Libya. The presence of rodents and sandflies makes it a suitable environment for Leishmania to spread in an endemic epidemiological pattern. Being engaged in farming activities or outdoor occupations increases the risk of infection. Various clinical patterns of CL suggest the presence of more than 1 species of Leishmania at Al-jabal Al-gharbi province. We propose that the 2 species responsible for CL in this area are L. major and L. tropica. Further investigations to identify the leishmanial species responsible for CL at Al-jabal Al-gharbi together with adoption of preventive and control programs are needed.

  6. An Epidemiological Study of Cutaneous Leishmaniasis in Al-Jabal Al-Gharbi, Libya

    PubMed Central

    Abdellatif, Manal Z. M.; El-Mabrouk, Khamis

    2013-01-01

    Cutaneous leishmaniasis (CL) is an endemic parasitic infection in the Mediterranean region, including Libya and its Al-jabal Al-gharbi province. We aimed at studying the occupational relevance as well as other epidemiological aspects of CL. We investigated 140 CL cases who attended at Gharyan outpatient polyclinic during a period of 6 months in 2009. CL infection was clinically diagnosed and confirmed by demonstration of Leishmania parasites on smears from lesions. Our findings showed that males were more affected than females (P=0.04), and people above 10-years were more affected than younger ones (P=0.0001). A significant percent of CL cases belonged to Al-Kawasem subprovince (P=0.0001). Farm-related activities were the most frequent occupations among CL cases (P=0.04). In addition to farm workers, housewives and students are at risk groups since they are engaged at farm activities. Moreover, those who have occupations that require staying outdoors for a part of night, e.g., policemen, are also at risk. Compared to children, adult CL patients had multiple lesions (P=0.001) that were more prevalent in their upper and lower extremities than the face (P=0.0001). We conclude that CL is a major health problem in Al-jabal Al-gharbi province of Libya. The presence of rodents and sandflies makes it a suitable environment for Leishmania to spread in an endemic epidemiological pattern. Being engaged in farming activities or outdoor occupations increases the risk of infection. Various clinical patterns of CL suggest the presence of more than 1 species of Leishmania at Al-jabal Al-gharbi province. We propose that the 2 species responsible for CL in this area are L. major and L. tropica. Further investigations to identify the leishmanial species responsible for CL at Al-jabal Al-gharbi together with adoption of preventive and control programs are needed. PMID:23467624

  7. Aberrant distributions of nuclear pore complex proteins in ALS mice and ALS patients.

    PubMed

    Shang, Jingwei; Yamashita, Toru; Nakano, Yumiko; Morihara, Ryuta; Li, Xianghong; Feng, Tian; Liu, Xia; Huang, Yong; Fukui, Yusuke; Hishikawa, Nozomi; Ohta, Yasuyuki; Abe, Koji

    2017-05-14

    Nuclear pore complexes (NPCs) play important roles in traffic of molecules between the nucleus and cytoplasm, aberrant distributions of components of NPCs were demonstrated in C9orf72 amyotrophic lateral sclerosis (C9-ALS) patients, but it is elusive whether such abnormities are also the case with other cause of ALS disease. In the present study, we investigated the spatiotemporal distributions of RanGAP1 and 4 representative nucleoporins (GP210, NUP205, NUP107 and NUP50) of NPCs in human Cu/Zn superoxide dismutase-1 mutation transgenic (SOD1-Tg) mice and sporadic ALS patients. Compared with wild type (WT), these proteins displayed age-dependent and progressive nuclear precipitations, and cytoplasmic aberrant expressions in motor neurons of lumbar cord in SOD1-Tg mice from 10 to 18weeks (W). Double immunofluorescent analysis showed abnormal nuclear retention and apparent co-localizations of RanGAPl with NUP205 and NUP205 with NUPl07, meanwhile, GP210 with NUP205 mainly co-localized in the nuclear envelope (NE) of motor neurons. Furthermore, RanGAP1, GP210 and NUP50 showed similarly abnormal nuclear precipitations and cytoplasmic upregulations in SOD1-Tg mice and ALS patients, moreover, aberrant co-localizations of RanGAP1 with TDP-43 and NUP205 with TDP-43 were also observed in motor neurons. The present study indicated that the mislocalization of these proteins of NPCs may underlie the pathogenesis of ALS both in SOD1-Tg mice and human sporadic ALS patients, and these dysfunctions may be a fundamental pathway for ALS that is not specific only in C9-ALS but also in SOD1-ALS, which may be amenable to pharmacotherapeutic intervention. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. Electrochemical formation of Al-Tm intermetallics in eutectic LiCl-KCl melt containing Tm and Al ions

    NASA Astrophysics Data System (ADS)

    Li, Xing; Yan, Yong-De; Zhang, Mi-Lin; Tang, Hao; Ji, De-Bin; Han, Wei; Xue, Yun; Zhang, Zhi-Jian

    2014-09-01

    This work focuses on investigating the electrochemical formation of Al-Tm and Al-Li-Tm alloys in LiCl-KCl-AlCl3-Tm2O3 melt on both W and Al electrodes. Thermodynamic calculation and electrochemical behavior of LiCl-KCl melt containing both AlCl3 and Tm2O3 showed that AlCl3 can chlorinate Tm2O3 to release Tm(III) ions. Three kinds of Al-Tm intermetallics at about -1.26, -1.32 and -1.43 V were detected by means of various electrochemical measurement techniques, i.e. cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry. Potentiostatic and galvanostatic electrolysis were carried out on Al and W electrodes to prepare Al-Tm and Al-Li-Tm alloys, respectively. The composition of Al-Li-Tm alloys was analyzed by inductive coupled plasma atomic emission spectrometer (ICP-AES).

  9. Revisiting Deng et al.'s Multiparty Quantum Secret Sharing Protocol

    NASA Astrophysics Data System (ADS)

    Hwang, Tzonelih; Hwang, Cheng-Chieh; Yang, Chun-Wei; Li, Chuan-Ming

    2011-09-01

    The multiparty quantum secret sharing protocol [Deng et al. in Chin. Phys. Lett. 23: 1084-1087, 2006] is revisited in this study. It is found that the performance of Deng et al.'s protocol can be much improved by using the techniques of block-transmission and decoy single photons. As a result, the qubit efficiency is improved 2.4 times and only one classical communication, a public discussion, and two quantum communications between each agent and the secret holder are needed rather than n classical communications, n public discussions, and 3n/2 quantum communications required in the original scheme.

  10. Al-Shebab: An Al-Qaeda Affiliate Case Study (2Rev)

    DTIC Science & Technology

    2017-10-01

    In Brief, Congressional Research Service, Report R43245, November 14, 2013, accessed May 19, 2017, https://fas.org/sgp/crs/row/R43245. pdf ; and...www.ctc.usma.edu/v2/wp-content/uploads/2014/09/CTCSentinel-Vol7Iss96. pdf . 10 Jane’s World Insurgency and Terrorism, “Harakat al-Shabaab al...gold and facilitates cash flows through mobile money transfers. When in power in Mogadishu in 2009-2010, al-Shebab controlled the main Bakara market

  11. Al Ghazali's Thoughts on Islamic Education Curriculum

    ERIC Educational Resources Information Center

    Barni, Mahyuddin; Mahdany, Diny

    2017-01-01

    Al Ghazali lived in the Islamic golden age when all the fields of education flourished. There have been many studies of al-Ghazali's thoughts, yet, further and deeper examination from various perspective is needed to get objective and actual thoughts of Al-Ghazali. In al Ghazali's time, there was no term of curriculum, however, the concept emerged…

  12. Solidification processing of intermetallic Nb-Al alloys

    NASA Technical Reports Server (NTRS)

    Smith, Preston P.; Oliver, Ben F.; Noebe, Ronald D.

    1992-01-01

    Several Nb-Al alloys, including single-phase NbAl3 and the eutectic of Nb2Al and NbAl3, were prepared either by nonconsumable arc melting in Ar or by zone processing in He following initial induction melting and rod casting, and the effect of the solidification route on the microstructure and room-temperature mechanical properties of these alloys was investigated. Automated control procedures and melt conditions for directional solidification of NbAl3 and the Nb2Al/Nb3Al eutectic were developed; high purity and stoichiometry were obtained. The effects of ternary additions of Ti and Ni are described.

  13. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    SciTech Connect

    Yadav, S. K.; Wang, J.; Liu, X. -Y.

    2016-06-13

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. Furthermore, the formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamically driven process.

  14. On the crack growth resistance and strength of the B2 iron aluminides Fe-40Al, Fe-45Al, and Fe-10Ni-40Al (at. %)

    SciTech Connect

    Schneibel, J.H.; Maziasz, P.J.

    1994-09-01

    The crack growth resistance and yield strength of the B2 iron aluminides Fe-40Al, Fe-45Al, are Fe-10Ni-40Al (at. %) have been investigated at room temperature laboratory air. After fast cooling from 1273 K, Fe-45Al and Fe-10Ni-40Al are much stronger than Fe-40Al, and exhibit considerably lower crack growth resistance. The crack growth resistance decreases with decreasing crack propagation velocity. Low crack propagation velocities favor intergranular fracture, whereas high velocities can lead to significant contributions from transgranular fracture. Boron additions to Fe-40Al and Fe-10Ni-40Al improve the crack growth resistance, reduce its dependence on the crack propagation velocity, and cause the path to be predominantly transgranular. In a plot of fracture toughness versus yield strength, the properties of the iron aluminides are similar to those of typical aluminum alloys.

  15. Ni{sub 3}Al technology transfer

    SciTech Connect

    Sikka, V.K.; Viswanathan, S.; Santella, M.L.

    1997-04-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, wire, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for: (1) high-strength castable composition for many applications that have been identified; (2) castability (mold type, fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) workability of cast or powder metallurgy product to sheet, bar, andmore » wire. The four issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes the work completed to address some of these issues during FY 1996.« less

  16. Ni{sub 3}Al technology transfer

    SciTech Connect

    Sikka, V.K.; Santella, M.L.; Alexander, D.J.

    1995-05-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for (1)high-strength castable composition for turbochargers, furnace furniture, and hot-die applications; (2) castability (fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) hot fabricability of cast ingots. All of the issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes work completed to address some of these issues during the fourth quarter of FY 1994.

  17. Development of SiAlON materials

    NASA Technical Reports Server (NTRS)

    Layden, G. K.

    1979-01-01

    Cold pressing and sintering techniques were used to produce ceramic test specimens in which the major phase was either Si3N4 or a solid solution having the beta Si3N4 structure. Additional components were incorporated to promote liquid phase sintering. Glass and/or crystalline phase were consequently retained in boundaries between Si3N4 grains which largely determined the physical properties of the bodies. Systems investigated most extensively included R-Si-Al-O-N (R = rare earth element) Zr-Si-Al-O-N, Y-Si-Be-O-N, and R1-R2-Si-O-N. Room temperature and 1370 C modulus of ruptured, 1370 C creep, and oxidation behavior are discussed in terms of phase relationships in a parent quinery, and relavent oxide systems.

  18. Dislocations penetrating an Al/Si interface

    NASA Astrophysics Data System (ADS)

    Zhang, Zhibo; Urbassek, Herbert M.

    2017-12-01

    We study indentation of a nanolayered material consisting of a Si top layer above an Al substrate, using molecular dynamics simulation. We focus on the activity of Si dislocations upon reaching the interface. We find that passage of the dislocations through the interface is possible, if the slip systems of the two crystals are aligned. Upon absorption at the interface, the Si dislocations generate slip which leads to 1-monolayer deep interface pits with well-defined steps; on the Al side dislocations and stacking fault planes are generated, which are pinned to the interface pit. For interfaces with not well aligned slip systems, the passage of dislocations is strongly suppressed. However, still interface pits, albeit with less well defined contours, and stacking fault planes aligned with the interface are created.

  19. DFT study of Al doped armchair SWCNTs

    SciTech Connect

    Dhiman, Shobhna, E-mail: s-dhiman@hotmail.com; Rani, Anita; Kumar, Ranjan

    2016-05-23

    Electronic properties of endohedrally doped armchair single-walled carbon nanotubes (SWCNTs) with a chain of six Al atoms have been studied using ab-initio density functional theory. We investigate the binding energy/atom, ionization potential, electron Affinity and Homo-Lumo gap of doped armchair SWNTs from (4,4) to (6,6) with two ends open. BE/dopant atom and ionization potential is maximum for (6, 6) doped armchair carbon nanotube; suggest that it is more stable than (4, 4) and (5, 5) doped tubes. HOMO - LUMO gap of Al doped arm chair carbon nanotubes decreases linearly with the increase in diameter of the tube. This showsmore » that confinement induce a strong effect on electronic properties of doped tubes. These combined systems can be used for future nano electronics. The ab–initio calculations were performed with SIESTA code using generalized gradient approximation (GGA).« less

  20. Finding Tracers for Supernova Produced 26Al

    NASA Astrophysics Data System (ADS)

    Young, Patrick A.; Ellinger, Carola I.; Arnett, David; Fryer, Chris L.; Rockefeller, Gabriel

    2009-07-01

    We consider the cospatial production of elements in supernova explosions to find observationally detectable proxies for enhancement of 26Al in supernova ejecta and stellar systems. Using four progenitors, we explore a range of one-dimensional explosions at different energies and an asymmetric three-dimensional explosion. We find that the most reliable indicator of the presence of 26Al in unmixed ejecta is a very low S/Si ratio (~0.05). Production of N in O/S/Si-rich regions is also indicative. The biologically important element P is produced at its highest abundance in the same regions. Proxies should be detectable in supernova ejecta with high spatial resolution multiwavelength observations, but the small absolute abundance of material injected into a proto-planetary disk makes detection unlikely in existing or forming stellar/planetary systems.

  1. Ni{sub 3}Al technology transfer

    SciTech Connect

    Sikka, V.K.; Viswanathan, S.; Santella, M.L.

    1997-04-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, wire, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for: (1) high-strength castable composition for many applications that have been identified; (2) castability (mold type, fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) workability of cast or powder metallurgy product to sheet, bar, and wire. The four issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes the work completed to address some of these issues during FY 1996.

  2. DFT study of Al doped armchair SWCNTs

    SciTech Connect

    Dhiman, Shobhna; Rani, Anita; Kumar, Ranjan; Dharamvir, Keya

    2016-05-23

    Electronic properties of endohedrally doped armchair single-walled carbon nanotubes (SWCNTs) with a chain of six Al atoms have been studied using ab-initio density functional theory. We investigate the binding energy/atom, ionization potential, electron Affinity and Homo-Lumo gap of doped armchair SWNTs from (4,4) to (6,6) with two ends open. BE/dopant atom and ionization potential is maximum for (6, 6) doped armchair carbon nanotube; suggest that it is more stable than (4, 4) and (5, 5) doped tubes. HOMO - LUMO gap of Al doped arm chair carbon nanotubes decreases linearly with the increase in diameter of the tube. This shows that confinement induce a strong effect on electronic properties of doped tubes. These combined systems can be used for future nano electronics. The ab–initio calculations were performed with SIESTA code using generalized gradient approximation (GGA).

  3. Hydrogen solubility of two-phase (Ti{sub 3}Al + TiAl) titanium aluminides

    SciTech Connect

    Takasaki, Akito; Ojima, Kozo; Taneda, Youji

    1995-06-01

    In this study, two-phase ({alpha}{sub 2} + {gamma}) titanium aluminides were thermally charged with hydrogen, and the hydrogen solubility and the hydrogen evolution behavior were investigated by means of thermal desorption spectroscopy (TDS). Hydrogen solubility of two-phase (Ti{sub 3}Al + TiAl) titanium aluminides occurred endothermically. A heat of solution for hydrogen dissolution in a Ti-50Al alloy was estimated to be 36.4 kJ/mol and that for a Ti-45 Al alloy was 58.3 kJ/mol in the temperatures range of 723 K to 843 K. At higher temperature, hydrogen solubility was not fitted well with Arrhenius type plots mainly because of oxidation. Itmore » was suggested from thermal desorption spectrums that there were three kinds of dissolution states for hydrogen in the alloys.« less

  4. Rechargeable Al/Cl2 battery with molten AlCl4/-/ electrolyte.

    NASA Technical Reports Server (NTRS)

    Holleck, G. L.; Giner, J.; Burrows, B.

    1972-01-01

    A molten salt system based on Al- and Cl2 carbon electrodes, with an AlCl3 alkali chloride eutectic as electrolyte, offers promise as a rechargeable, high energy density battery which can operate at a relatively low temperature. Electrode kinetic studies showed that the electrode reactions at the Al anode were rapid and that the observed passivation phenomena were due to the formation at the electrode surface of a solid salt layer resulting from concentration changes on anodic or cathodic current flow. It was established that carbon electrodes were intrinsically active for chlorine reduction in AlCl3-alkali chloride melts. By means of a rotating vitreous carbon disk electrode, the kinetic parameters were determined.

  5. Adherent Al2O3 scales produced on undoped NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    1986-01-01

    Repeated oxidation and polishing of high purity Ni-15Cr-13Al has dramatically changed its cyclic oxidation behavior from nonadherent to adherent. No apparent change in scale phase, morphology or interface structure occurred during this transition, dismissing any mechanism based on pegging, vacancy sink, or growth stress. The principle change that did occur was a reduction in the sulfur content from 10 ppmw to 3 ppmw after 25 cycles at 1120 C. These observations are used to support the model of Al2O3 scale adherence put forth by Smeggil et al. which claims that Al2O3 scale spallation occurs due to sulfur segregation and bond deterioration at the oxide-metal interface.

  6. 'Abd al-Rahman al-Sufi's 3-Step Magnitude System

    NASA Astrophysics Data System (ADS)

    Hafez, Ihsan; Stephenson, F. Richard; Orchiston, Wayne

    'Abd al-Rahmān al-ūfī's Book of the Fixed Stars dates from around AD 964 and is one of the most important medieval Arabic treatises on astronomy. In this paper we begin with a very brief introduction to the Book of the Fixed Stars. This book contains an extensive star catalogue that lists star coordinates and magnitude estimates for all of the Ptolemaic stars. However, in his book al-hūfī utilized three distinct intermediate magnitude values whereas Ptolemy only mentioned two. We believe that al-hūfī used what we have termed a '3-step intermediate magnitude system,' which is more accurate than Ptolemy's 2-step intermediate system. In this paper we examine in detail the accuracy of this unique 3-step system in comparison with Ptolemy's and modern magnitude values.

  7. Gate Bias Dependent Two Layer Conduction in InAlN/AlN/GaN Heterostructures

    NASA Astrophysics Data System (ADS)

    Cheng, Hailing; Kurdak, Cagliyan; Leach, Jacob; Ni, Xianfeng; Li, Xing; Wu, Mo; Ozgur, Umit; Morkoc, Hadis; Zhou, Lin; Smith, David; Vurgaftman, Igor; Meyer, Jerry

    2010-03-01

    We studied InAlN/AlN/GaN heterostructures with In compositions near 17% grown by Organo-Metallic Vapor Phase Epitaxy. These structures are free of strain and provide the confinement needed for a relatively high density and high mobility two-dimensional electron gas. The cross-sectional TEM images indicate the presence of an inadvertent GaN layer formed between the InAlN and AlN layers during the growth. Using Shubnikov-de Haas and Hall measurements performed on gated Hall bar samples at 4.2 K, we find that this additional GaN layer acts as a parasitic conduction channel. The quantitative mobility spectrum analysis of our data indicates that this parasitic channel has a very low mobility, and can be depleted by the application of a negative gate voltage.

  8. Morphology, granulometric and structural phase composition of mechanically synthesized composite powder Al-Mg+Al/MWCNTs

    NASA Astrophysics Data System (ADS)

    Aborkin, A. V.; Sobol’kov, A. V.; Kireev, A. V.; Volochko, A. T.; Izobello, A. Yu; Sachkova, N. V.; Sytschev, A. E.

    2018-01-01

    A method of mechanical synthesis in a planetary ball mill produced composite powders based on a nanocrystalline Al-Mg matrix reinforced with micro additives of Al / MWCNTs. The granulometric composition of the obtained composite powders was studied. It has been established that the concentration of Al / MWCNTs does not significantly affect the average particle size of the composite powder formed in the process of mechanical synthesis. The resulting composite powders were studied by X-ray diffraction analysis. The influence of the Al / MWCNTs concentration on the size of the coherent scattering regions of the synthesized powder is determined. The morphology of the resulting composite powders was studied by high-resolution scanning microscopy. The resulting powders can be used in the creation of bulk composite materials and functional coatings.

  9. Laughter, crying and sadness in ALS

    PubMed Central

    Thakore, Nimish J; Pioro, Erik P

    2017-01-01

    Background Pseudobulbar affect (PBA) is prevalent in amyotrophic lateral sclerosis (ALS), but there is limited information on its associations and course. Objectives Explore prevalence, associations, course and manifestations of PBA in outpatient cohort of patients with ALS and examine its relationship to depression. Methods Self-reported measures of PBA and depression (Center for Neurologic Study-Lability Scale (CNS-LS) and Patient Health Questionnaire (PHQ-9), respectively) were obtained from consecutive patients with ALS using tablet devices in waiting rooms (Knowledge Program). Results PBA (CNS-LS ≥13) was seen in 209/735 patients (28.4%). PBA was associated with bulbar onset and dysfunction, upper motor neuron dysfunction, cognitive impairment, depression and lower quality of life. A multivariable model that included lower bulbar and gross motor subscores, female gender, younger age and shorter duration of disease predicted PBA with 74% accuracy. CNS-LS scores increased only slowly with time. Women with PBA reported more crying than men. Crying (but not laughter) correlated with depression, and crying was associated with poorer quality of life. Exploratory factor analysis of pooled questions of CNS-LS and PHQ-9 identified three underlying factors (laughter, crying and depression) loaded on appropriate questions of the respective instruments. Conclusion This study identifies associations of PBA and additionally finds PBA (especially crying-predominant PBA) more prevalent in women with ALS. Although the two self-report instruments (CNS-LS and PHQ-9) discriminate well between PBA and depression, there is significant overlap between depression and crying in PBA. Studies of PBA should stratify for gender, examine crying and laughter as separate outcomes and adjust for depression. PMID:28572273

  10. Al Qaeda’s Seapower Strategy

    DTIC Science & Technology

    2011-08-08

    global oil movement persists though, as revealed in the documents and media recovered from the assault on UBL’s compound. 1 But does AQ have a...based the then-robust Somalian Navy. The port now provides what is likely al Shabaab’s primary source of revenue, via taxes on imports and exports . In...National Council (TNC) rebels. This port is essential for exporting the TNC’s oil and supporting logistics and humanitarian operations for anti-Gadhafi

  11. The Strategic Failures of al Qaeda

    DTIC Science & Technology

    2010-01-01

    place in that nation’s future. Their attempted uprising in Saudi Arabia has been crushed. Al Qaeda and the Taliban were routed from Afghanistan in...Rev. 8-98) Prescribed by ANSI Std Z39-18 Spring 2010 61 Five Critical Mistakes Five critical mistakes are apparent, each of which had a...that governments in the Arab world were placed in power, are kept in power, and are subservient to the United States, and if America were forced to

  12. Diet and dietetics in al-Andalus.

    PubMed

    Salas-Salvadó, Jordi; Huetos-Solano, Maria D; García-Lorda, Pilar; Bulló, Mònica

    2006-08-01

    Al-Andalus society (711-1492) based its idea of health on the wisdom of Classical Greece, the Hippocratic-Galenic theories, as well as the Persian and Hindu cultures. The twelfth century in al-Andalus is considered to be the most prolific period for works of a scientific and technical nature. At the time, the main treatises on dietetics were written and this science reached its widest expression with such leading figures as Ibn Wāfīd, Avenzoar, Averroes and Maimonides, whose works revealed the first scientific knowledge on the nutritional processes of the human body. Diet was regarded as being essential for health and the prevention of disease. Dietary guidelines were written for different age groups, different body types and different seasons of the year. The amount of food to be ingested, the number of meals recommended and the order in which the food should be consumed were all issues that were discussed. A variety of foods were thought to have medicinal properties, some of which are known today. The diet in al-Andalus was varied and very probably made a substantial contribution to the origin of the present-day Mediterranean diet, rich in olive oil, wholemeal cereals, fruit and vegetables, fish, lamb, poultry, nuts and spices. We also find that many of the terms in current use in diet and agriculture are a living testimony to the Arabic influence, as are many of the dishes of our varied Mediterranean gastronomy.

  13. Superbends expand the scope of Berkeley's ALS

    SciTech Connect

    Robin, David S.; Robinson, Arthur L.; Tamura, Lori S.

    2002-01-22

    While the ALS has turned out to be a world-leader in providing beams of soft X-rays -- indeed, furnishing these beams remains its core mission -- there has nonetheless been a steadily growing demand from synchrotron radiation users for harder X-rays with higher photon energies. The clamor has been strongest from protein crystallographers whose seemingly insatiable appetite for solving structures of biological macromolecules could not be satisfied by the number of crystallography beamlines available worldwide. But how to provide these X-rays in a cost-effective way without disrupting the thriving research programs of the existing ALS users was the problem. Superconductingmore » bend magnets (superbends) provided the answer for the ALS, which adopted a proposal to replace some of the normal combined-function (gradient) magnets in the curved arcs of the storage ring with superconducting dipoles that could generate higher magnetic fields and thus synchrotron light with a higher critical energy.« less

  14. Lower motor neuron dysfunction in ALS.

    PubMed

    de Carvalho, Mamede; Swash, Michael

    2016-07-01

    In the motor system there is a complex interplay between cortical structures and spinal cord lower motor neurons (LMN). In this system both inhibitory and excitatory neurons have relevant roles. LMN loss is a marker of motor neuron disease/amyotrophic lateral sclerosis (MND/ALS). Conventional needle electromyography (EMG) does not allow LMN loss to be quantified. Measurement of compound muscle action potential (CMAP) amplitude or area, and the neurophysiological index, provide a surrogate estimate of the number of functional motor units. Increased motor neuronal excitability is a neurophysiological marker of ALS in the context of a suspected clinical and electrophysiological diagnosis. In the LMN system, fasciculation potentials (FPs) are the earliest changes observed in affected muscles, a feature of LMN hyperexcitability. Reinnervation is best investigated by needle EMG although other methods can be explored. Moreover needle EMG give information about the temporal profile of the reinnervation process, important ancillary data. Quantitative motor unit potential analysis is a valuable method of evaluating reinnervation. The importance of FPs has been recognized in the Awaji criteria for the electrodiagnosis of ALS, criteria that are a sensitive adjunct to the revised El Escorial criteria. Finally, functionality of LMN's, and perhaps excitability studies in motor nerves, aids understanding of the disease process, allowing measurement of potential treatment effects in clinical trials. Other investigational techniques, such as electrical impedance myography, muscle and nerve ultrasound, and spinal cord imaging methods may prove useful in future. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  15. Simulation of aluminothermic smelting of Al-Zr and Al-Zr-Mo-Sn alloys

    NASA Astrophysics Data System (ADS)

    Larionov, A. V.; Chumarev, V. M.; Udoeva, L. Yu.; Mansurova, A. N.; Rylov, A. N.; Raikov, A. Yu.; Aleshin, A. P.; Trubachev, M. V.

    2013-09-01

    Aluminothermic smelting of Al-Zr and Al-Zr-Mo-Sn alloys has been simulated in terms of thermodynamics. The thermodynamic properties of molybdenum and zirconium intermetallic compounds are calculated. It is demonstrated that, with consideration for their formation, the calculated compositions of aluminothermic blends and the forecasted extraction of target metals into an alloy are in good agreement with the data obtained during pilot tests.

  16. Three-Dimensional FIB/EBSD Characterization of Irradiated HfAl3-Al Composite

    SciTech Connect

    Hua, Zilong; Guillen, Donna Post; Harris, William; Ban, Heng

    2016-09-01

    A thermal neutron absorbing material, comprised of 28.4 vol% HfAl3 in an Al matrix, was developed to serve as a conductively cooled thermal neutron filter to enable fast flux materials and fuels testing in a pressurized water reactor. In order to observe the microstructural change of the HfAl3-Al composite due to neutron irradiation, an EBSD-FIB characterization approach is developed and presented in this paper. Using the focused ion beam (FIB), the sample was fabricated to 25µm × 25µm × 20 µm and mounted on the grid. A series of operations were carried out repetitively on the sample top surface to prepare it for scanning electron microscopy (SEM). First, a ~100-nm layer was removed by high voltage FIB milling. Then, several cleaning passes were performed on the newly exposed surface using low voltage FIB milling to improve the SEM image quality. Last, the surface was scanned by Electron Backscattering Diffraction (EBSD) to obtain the two-dimensional image. After 50 to 100 two-dimensional images were collected, the images were stacked to reconstruct a three-dimensional model using DREAM.3D software. Two such reconstructed three-dimensional models were obtained from samples of the original and post-irradiation HfAl3-Al composite respectively, from which the most significant microstructural change caused by neutron irradiation apparently is the size reduction of both HfAl3 and Al grains. The possible reason is the thermal expansion and related thermal strain from the thermal neutron absorption. This technique can be applied to three-dimensional microstructure characterization of irradiated materials.

  17. Al Sahawa - The Awakening, Volume 4: Al Anbar Province, Area of Operations Topeka, Ramadi

    DTIC Science & Technology

    2016-08-01

    four of them, we’re dead meat !” And so that’s the reason why we didn’t build anything over there. After Sofia, we felt like we could justify it...Al Hamadani- Hit 38- Jbayer Saleh Khalaf Al Laheeb – Hit 39...became an asset and not a liability . Because going out there, I would think that any all-male Marine unit, infantry unit, or armor unit, is going to

  18. Al Sahawa - The Awakening. Volume 4: Al Anbar Province, Area of Operations Topeka, Ramadi

    DTIC Science & Technology

    2016-08-01

    four of them, we’re dead meat !” And so that’s the reason why we didn’t build anything over there. After Sofia, we felt like we could justify it...Al Hamadani- Hit 38- Jbayer Saleh Khalaf Al Laheeb – Hit 39...became an asset and not a liability . Because going out there, I would think that any all-male Marine unit, infantry unit, or armor unit, is going to

  19. Three-Dimensional FIB/EBSD Characterization of Irradiated HfAl3-Al Composite

    SciTech Connect

    Hua, Zilong; Guillen, Donna Post; Harris, William

    2016-09-01

    A thermal neutron absorbing material, comprised of 28.4 vol% HfAl3 in an Al matrix, was developed to serve as a conductively cooled thermal neutron filter to enable fast flux materials and fuels testing in a pressurized water reactor. In order to observe the microstructural change of the HfAl3-Al composite due to neutron irradiation, an EBSD-FIB characterization approach is developed and presented in this paper. Using the focused ion beam (FIB), the sample was fabricated to 25µm × 25µm × 20 µm and mounted on the grid. A series of operations were carried out repetitively on the sample top surface tomore » prepare it for scanning electron microscopy (SEM). First, a ~100-nm layer was removed by high voltage FIB milling. Then, several cleaning passes were performed on the newly exposed surface using low voltage FIB milling to improve the SEM image quality. Last, the surface was scanned by Electron Backscattering Diffraction (EBSD) to obtain the two-dimensional image. After 50 to 100 two-dimensional images were collected, the images were stacked to reconstruct a three-dimensional model using DREAM.3D software. Two such reconstructed three-dimensional models were obtained from samples of the original and post-irradiation HfAl3-Al composite respectively, from which the most significant microstructural change caused by neutron irradiation apparently is the size reduction of both HfAl3 and Al grains. The possible reason is the thermal expansion and related thermal strain from the thermal neutron absorption. This technique can be applied to three-dimensional microstructure characterization of irradiated materials.« less

  20. Bulk Al-Al3Zr composite prepared by mechanical alloying and hot extrusion for high-temperature applications

    NASA Astrophysics Data System (ADS)

    Pourkhorshid, E.; Enayati, M. H.; Sabooni, S.; Karimzadeh, F.; Paydar, M. H.

    2017-08-01

    Bulk Al/Al3Zr composite was prepared by a combination of mechanical alloying (MA) and hot extrusion processes. Elemental Al and Zr powders were milled for up to 10 h and heat treated at 600°C for 1 h to form stable Al3Zr. The prepared Al3Zr powder was then mixed with the pure Al powder to produce an Al-Al3Zr composite. The composite powder was finally consolidated by hot extrusion at 550°C. The mechanical properties of consolidated samples were evaluated by hardness and tension tests at room and elevated temperatures. The results show that annealing of the 10-h-milled powder at 600°C for 1 h led to the formation of a stable Al3Zr phase. Differential scanning calorimetry (DSC) results confirmed that the formation of Al3Zr began with the nucleation of a metastable phase, which subsequently transformed to the stable tetragonal Al3Zr structure. The tension yield strength of the Al-10wt%Al3Zr composite was determined to be 103 MPa, which is approximately twice that for pure Al (53 MPa). The yield stress of the Al/Al3Zr composite at 300°C is just 10% lower than that at room temperature, which demonstrates the strong potential for the prepared composite to be used in high-temperature structural applications.

  1. Motor function and behaviour across the ALS-FTD spectrum.

    PubMed

    De Silva, D; Hsieh, S; Caga, J; Leslie, F V C; Kiernan, M C; Hodges, J R; Mioshi, E; Burrell, J R

    2016-05-01

    Behavioural/functional disturbances, characteristic of frontotemporal dementia (FTD), are also a feature of amyotrophic lateral sclerosis (ALS) and patients with combined ALS and FTD (FTD-ALS). To investigate the progression of behavioural disturbances in ALS and FTD using the FTD functional rating scale (FTDFRS). Patients with ALS, FTD-ALS and FTD were recruited from specialist clinics. Baseline assessments included the FTDFRS and the ALS functional rating scale-revised (ALSFRS-R). Baseline assessments were included, as were longitudinal assessments in a proportion of patients. In total, 21 ALS, 12 FTD-ALS and 14 behavioural variant FTD (bvFTD) patients were included in the study. Moderate or severe behavioural disturbance was common in patients with ALS at baseline (47.6%), although less frequent than in bvFTD patients; patients with FTD-ALS displayed intermediate impairment. The ALSFRS-R showed the opposite pattern and did not correlate with the FTDFRS. During the follow-up period, significant (P < 0.05) behavioural deterioration was demonstrated in patients with bvFTD and FTD-ALS, with a trend for decline in patients with ALS (P = 0.06). Motor disturbance is the primary marker of disease severity in ALS, but behavioural and functional impairment are common, and may decline independently of motor function. As such, the FTDFRS may provide valuable information in the assessment and monitoring of ALS. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. A comparative wear study on Al-Li and Al-Li/SiC composite

    SciTech Connect

    Okumus, S. Cem Karslioglu, Ramazan Akbulut, Hatem

    2013-12-16

    Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al{sub 2}O{sub 3} ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms{sup −1} and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth and diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.

  3. FeAl and NbAl3 Intermetallic-HVOF Coatings: Structure and Properties

    NASA Astrophysics Data System (ADS)

    Guilemany, J. M.; Cinca, N.; Dosta, S.; Cano, I. G.

    2009-12-01

    Transition metal aluminides in their coating form are currently being explored in terms of resistance to oxidation and mechanical behavior. This interest in transition metal aluminides is mainly due to the fact that their high Al content makes them attractive for high-temperature applications. This is also a reason to study their resistance to wear; they may be suitable for use in applications that produce a lot of wear in aggressive environments, thus replacing established coating materials. In this study, the microstructure, microhardness, and wear and oxidation performance of FeAl and NbAl3 coatings produced by high-velocity oxy-fuel spraying are evaluated with two main aims: (i) to compare these two coating systems—a commonly studied aluminide (FeAl) and, NbAl3, an aluminide whose deposition by thermal spraying has not been attempted to date—and (ii) to analyze the relationship between their microstructure, composition and properties, and so clarify their wear and oxidation mechanisms. In the present study, the higher hardness of niobium aluminide coatings did not correlate with a higher wear resistance and, finally, although pesting phenomena (disintegration in oxidizing environments) were already known of in bulk niobium aluminides, here their behavior in the coating form is examined. It was shown that such accelerated oxidation was inevitable with respect to the better resistance of FeAl, but further improvements are foreseen by addition of alloying elements in that alloy.

  4. Redistribution of Ti and Al in deuterium charged TiAl

    NASA Technical Reports Server (NTRS)

    Legzdina, D.; Robertson, I. M.; Birnbaum, H. K.

    1992-01-01

    The redistribution of titanium and aluminum in a single-phase TiAl alloy that has been exposed to a high pressure of deuterium gas at high temperature is studied. The microstructure in the as-received, uncharged condition consisted of single-phase gamma TiAl grains and a random distribution of precipitates. Precipitates were distributed throughout the matrix and along the grain boundaries. The chemistry of the precipitates varied considerably; some were rich in Al, while other were mostly Ti with some Si and Al. The dislocation density in most grains was low, although in a few grains a high dislocation density was observed. FCC deuterides with a lattice parameter of 0.45 nm form in a Ti-52.1Al-2.1Ta (at. pct) alloy after exposure to 1.38 MPa of deuterium gas at 650 C for 213 hr. The structure and lattice parameter are consistent with the formation of Ti(l)D2. The deuterides that form in this alloy are enriched in Ti and deficient in Al and Ta compared to the deuteride-free matrix. Regions of the matrix contiguous with the deuterides have a correspondingly enhanced aluminum and tantalum concentration.

  5. TEM and HRTEM characterization of TiAl diffusion bonds using Ni/Al nanolayers.

    PubMed

    Simões, Sónia; Viana, Filomena; Ramos, Ana S; Vieira, Maria T; Vieira, Manuel F

    2015-02-01

    Diffusion bonding of TiAl alloys can be enhanced by the use of reactive nanolayer thin films as interlayers. Using these interlayers, it is possible to reduce the conventional bonding conditions (temperature, time, and pressure) and obtain sound and reliable joints. The microstructural characterization of the diffusion bond interfaces is a fundamental step toward understanding and identifying the bonding mechanisms and relating them to the strength of the joints. The interface of TiAl samples joined using Ni/Al nanolayers was characterized by transmission electron microscopy and scanning transmission electron microscopy. Microstructural characterization of the bond revealed that the interfaces consist of several thin layers of different composition and grain size (nanometric and micrometric). The bonding temperature (800, 900, or 1,000°C) determines the grain size and thickness of the layers present at the interface. Phase identification by high-resolution transmission electron microscopy combined with fast Fourier transform and electron energy-loss spectroscopy analyses reveals the presence of several intermetallic compounds: AlTiNi, NiAl, and Al2TiNi. For bonds produced at 800 and 900°C, nanometric grains of Ti were detected at the center of the interface.

  6. A comparative wear study on Al-Li and Al-Li/SiC composite

    SciTech Connect

    Okumus, S. Cem, E-mail: cokumus@sakarya.edu.tr; Karslioglu, Ramazan, E-mail: cokumus@sakarya.edu.tr; Akbulut, Hatem, E-mail: cokumus@sakarya.edu.tr

    2013-12-16

    Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al{sub 2}O{sub 3} ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms{sup −1} and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth andmore » diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.« less

  7. [Al3+ Absorption and Assimilation by Four Ectomycorrhizal Fungi].

    PubMed

    Wang, Ming-xia; Yuan, Ling; Huang, Jian-guo; Zhou, Zhi-feng

    2015-09-01

    The present experiment was carried out in order to know the resistance mechanism of the ectomycorrhizal (ECM) fungi under Al stress, to establish the theoretical foundation to alleviate the Al toxicity of trees, to guide the selection of Al-resisted ECM fungi and preserve forest health. The absorption and assimilation of Al3+ by four ECM fungi [Pisolithus tinctorius (Pt 715), Suillus luteus (Sl 08 and Sl 14), Gyroporus cyanescens (Gc 99)], which were isolated from different forest soils, were investigated in pure culture in liquid media. The growths of Pt 715 and Sl 08 were less affected by Al3+, but growths of S114 and Gc 99 were obviously inhibited by Al3+. With the increasing of Al3+ concentration in culture, the absorption and assimilation of Al3+ by four ECM fungi increased. It indicated that the concentration of Al3+ in environments might be the primary factor determining the Al3+ content in the cell of each tested fungi. Amounts of Al3+ absorbed (in total or calculated in unit hyphae) by the Al3+ tolerant strains (Pt 715 and Sl 08) were significantly lower than those by the Al3+ sensitive strains (S1 14 and Gc 99), which illustrated that reducing the absorption of Al3+ under Al3+ stress environment might be an effective approach to alleviate the Al3+ poison for these Al3+ tolerant strains. Furthermore, Al3+ stress could stimulate the ECM fungi to assimilate more N, P, and K, which might indicate that increasing requirement of the nutrients also could be helpful for ECM fungi to fight against the harmful effects caused by Al3+ stress.

  8. RETRACTED ARTICLE: Microstructures and morphologies of B2-Ordered NiAl(Co) and FeAl(Co)

    NASA Astrophysics Data System (ADS)

    Oh, Chang-Sup; Han, Chang-Suk

    2013-03-01

    Fine dispersion of disordered phases is obtained in a Ni-Al-Co and Fe-Al-Co ternary system. A transmission electron microscopy investigation has been performed in the present work on the precipitation of supersaturated B2-ordered (Ni,Co)Al and α-Fe in B2-ordered FeAl(Co) with different stoichiometries. Precipitation behavior and hardening were investigated by measuring the hardness variation. The hardness of (Ni,Co)Al and B2-FeAl(Co) increased appreciably by the fine precipitation of (Ni,Co)2Al, α-Fe, and overage softening occurred after prolonged aging. In case of B2-ordered (Ni,Co)Al, the (Ni,Co)2Al phase had a hexagonal structure and took a rod-like shape with the long axis of the rod parallel to the <111> directions of the B2 matrix. By aging at temperatures below 873 K, a long period superlattice structure appeared in the hexagonal (Ni,Co)2Al phase. The orientation relationship between the (Ni,Co)2Al precipitates and the B2-(Ni,Co)Al matrix was (0001)p//(111)B2 and [bar 12bar 10]_p //[bar 110]_{B2}, where the suffix p and B2 denote the (Ni,Co)2Al precipitate and the B2-(Ni,Co)Al matrix, respectively. (Ni,Co)Al hardened appreciably by the fine precipitation of the (Ni,Co)2Al phase. On the other hand, in case of B2-FeAl(Co), the disordered α-Fe phase was present as a precipitate in a B2-FeAl(Co) matrix and had a cubic-cubic orientation with the matrix. At the early aging periods, prismatic dislocation loops formed in the B2-FeAl(Co) matrix. B2-FeAl(Co) matrix was typically hardened by the precipitation of α-Fe.

  9. Transitions in Al Coordination During Gibbsite Crystallization Using High-Field 27Al and 23Na MAS NMR Spectroscopy

    SciTech Connect

    Hu, Jian Z.; Zhang, Xin; Jaegers, Nicholas R.

    2017-11-15

    Mechanisms of nucleation and growth of Al hydroxides such as gibbsite from aqueous solution, particularly in highly alkaline conditions, remain poorly understood. In this work, quantitative 27Al and 22Na MAS NMR experiments were conducted on solid samples extracted from the crystallization of gibbsite from an amorphous aluminum hydroxide gel precursor. The use of high magnetic field and fast sample spinning allowed transitional tetrahedral (AlT) and pentahedral (AlP) aluminum species to be observed along with the octahedral aluminum (AlO) that dominates the gibbsite product. Low-coordinated Al species could be detected at concentrations as low as 0.1% of the total Al sites.more » It is established that (a) AlT and AlP coexist on the surface of growing gibbsites even with a combined percentage over the total Al sites of less than 1%; (b) Different synthesis methods generate gibbsite with varying amounts of low-coordinated Al; (c) the amorphous gel precursor contains a significant amount of low-coordinated Al sites with AO: AlP: AlT ratios of approximately 4:2:1; (d) upon hydration, the external, low-coordinated Al sites become six-fold coordinated by interacting with the oxygen in H2O and the 27Al MAS NMR peak position shifts to that for the AlO sites; (e) gibbsite with increased long range order is synthesized over longer times by gradually incorporating residual AlP and AlT sites into octahedrally-coordinated AlO sites; (f) trace Na is predominantly a surface species on gibbsite particles. These findings provide a basis for understanding the gibbsite crystallization mechanism, along with a general means of characterizing gibbsite surface properties that are of equal importance for understanding related processes such as dissolution behavior.« less

  10. Solidification Behavior of gamma'-Ni3Al Containing Alloys in the Ni-Al-O System

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2007-01-01

    The chemical activities of Al and Ni in gamma(prime)-Ni3Al-containing systems were measured using the multi-cell Knudsen effusion-cell mass spectrometry technique (multi-cell KEMS), over the composition range 8 - 32 at.%Al and temperature range T = 1400 - 1750 K. From these measurements a better understanding of the equilibrium solidification behaviour of gamma(prime)-Ni3Al-containing alloys in the Ni-Al-O system was established. Specifically, these measurements revealed that (1) gamma(prime)-Ni3Al forms via the peritectiod reaction, gamma + Beta (+ A12O3) = gamma (prime) (+ Al2O3), at 1633 +/- 1 K, (2) the {gamma + Beta + Al2O3} phase field is stable over the temperature range 1633 through 1640 K, and (3) equilibrium solidification occurs by the eutectic reaction, L (+ Al2O3) = gamma + Beta (+ Al2O3), at 1640 +/- 1 K and a liquid composition of 24.8 +/- 0.2 at.%Al (at an unknown oxygen content). When projected onto the Ni-Al binary, this behaviour is inconsistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady-state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma(prime)-Ni3Al phase field.

  11. Creep and Toughness of Cryomilled NiAl Containing Cr

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Aikin, Beverly; Salem, Jon

    2000-01-01

    NiAl-AlN + Cr composites were produced by blending cryomilled NiAl powder with approx. 10 vol % Cr flakes. In comparison to the as-consolidated matrices, hot isostatically pressed Cr-modified materials did not demonstrate any significant improvement in toughness. Hot extruded NiAl-AlN+10.5Cr, however, possessed a toughness twice that determine for the base NiAl-AlN alloy. Measurement of the 1200 to 1400 K plastic flow properties revealed that the strength of the composites was completely controlled by the properties of the NiAl-AlN matrices. This behavior could be successfully modeled by the Rule-of-Mixtures, where load is shed from the weak Cr to the strong matrix.

  12. The oxidation of Ni-rich Ni-Al intermetallics

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph; Smialek, James L.; Barrett, Charles A.

    1988-01-01

    The oxidation of Ni-Al intermetallic alloys in the beta-NiAl phase field and in the two phase beta-NiAl/gamma'-Ni3Al phase field has been studied between 1000 and 1400 C. The stoichiometric beta-NiAl alloy doped with Zr was superior to other alloy compositions under cyclic and isothermal oxidation. The isothermal growth rates did not increase monotonically as the alloy Al content was decreased. The characteristically ridged alpha-Al2O3 scale morphology, consisting of cells of thin, textured oxide with thick growth ridges at cell boundaries, forms on oxidized beta-NiAl alloys. The correlation of scale features with isothermal growth rates indicates a predominant grain boundary diffusion growth mechanism. The 1200 C cyclic oxidation resistance decreases near the lower end of the beta-NiAl phase field.

  13. Study of the 26Al(n,p)26Mg and 26Al(n,α)23Na reactions using the 27Al(p,p')27Al inelastic scattering reaction

    NASA Astrophysics Data System (ADS)

    Benamara, S.; de Séréville, N.; Adsley, P.; Laird, A. M.; Hammache, F.; Stefan, I.; Roussel, P.; Ancelin, S.; Assié, M.; Barton, C.; Coc, A.; Diget, C.; Deloncle, I.; Fox, S.; Guillot, J.; Hamadache, C.; Kiener, J.; Le Crom, B.; Lefebvre, L.; Lefebfre-Schuhl, A.; Marquinez Duran, G.; Mavilla, G.; Morfouace, P.; Mutschler, A.; Nsangu, C. T.; Perrot, L.; Oulebsir, N.; Sánchez-Benítez, Á.-M.; Suzuki, D.; Tatischeff, V.; Vandebrouck, M.

    2016-01-01

    26Al was the first cosmic radioactivity ever detected in the galaxy as well as one of the first extinct radioactivity observed in refractory phases of meteorites. Its nucleosynthesis in massive stars is still uncertain mainly due to the lack of nuclear information concerning the 26Al(n,p)26Mg and 26 Al(n,α)23Na reactions. We report on a single and coincidence measurement of the 27Al(p,p')27Al(p)26Mg and 27Al(p,p')27Al(α)23Na reactions performed at the Orsay TANDEM facility aiming at the spectroscopy study of 27Al above the neutron threshold. Fourteen states are observed for the first time within 350 keV above the 26Al+n threshold.

  14. Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode

    NASA Astrophysics Data System (ADS)

    Xu, Yuan; Chang, Benkang; Chen, Xinlong; Qian, Yunsheng

    2017-08-01

    We designed two transmission-mode GaAs/AlGaAs photocathodes with different Al x Ga1-x As layers, one has an Al x Ga1-x As layer with the Al component ranging from 0.9 to 0, and the other has a fixed Al component 0.7. Using the first-principle method, we calculated the electronic structure and absorption spectrum of Al x Ga1-x As at x = 0, 0.25, 0.5, 0.75 and 1, calculation results suggest that with the increase of the Al component, the band gap of Al x Ga1-x As increases. Then we activated the two samples, and obtained the spectral response curves and quantum efficiency curves; it is found that sample 1 has a better shortwave response and higher quantum efficiency at short wavelengths. Combined with the band structure diagram of the transmission-mode GaAs/AlGaAs photocathode and the fitted performance parameters, we analyze the phenomenon. It is found that the transmission-mode GaAs/AlGaAs photocathode with variable Al component and various doping structure can form a two-stage built-in electric field, which improves the probability of shortwave response photoelectrons escaping to the vacuum. In conclusion, such a structure reduces the influence of back-interface recombination, improves the shortwave response of the transmission-mode photocathode. Project supported by the National Natural Science Foundation of China (Nos. 91433108, 61301023).

  15. Gaussian density-functional study for small neutral (Al n ), positive (Al{/n +}) and negative (Al{/n -}) aluminium clusters ( n=2 5)

    NASA Astrophysics Data System (ADS)

    Calaminici, Patrizia; Russo, Nino; Toscano, Marirosa

    1995-12-01

    The structures and properties of Al n , Al{/n +}, Al{/n -} ( n=1,5) clusters have been investigated by using the Linear Combination of Gaussian Type Orbitals (LCGTO) method, considering Local (LSD) and Non Local (NLSD) Spin Density Approximations and employing a Model Core Potential (MCP) that allows the explicit treatment of 3 s 2 3 p 1 valence electrons. For each system different geometrical structures and electronic states have been considered. For Al3, Al{3/+}, Al{3/-} the most stable geometry proved to be the equilateral triangle ( D 3 h ). Al4 and Al{4/+} prefer the rhombus ( D 2 h ) structure, while the corresponding anion prefers the square ( D 4 h ) one. The trapezoidal form ( C 2 v ) is the most stable isomer for Al5, Al{5/+} and Al{5/-} clusters. The analysis of vibrational frequencies shows that these structures are minima in the potential energy surface. The binding energies ( D e), the adiabatic ionization potentials (IP) and electron affinities (EA), the chemical potentials or absolute hardnesses (η) and electronegativities (χ) have been computed. Results are in good agreement with the available experimental data and the previous high level theoretical computations.

  16. Formation of Al/(Al13Fe4 + Al2O3) Nano-composites via Mechanical Alloying and Friction Stir Processing

    NASA Astrophysics Data System (ADS)

    Azimi-Roeen, Ghasem; Kashani-Bozorg, Seyed Farshid; Nosko, Martin; Nagy, Štefan; Maťko, Igor

    2018-01-01

    Combination of mechanical alloying and friction stir processing was used for the fabrication of Al/(Al13Fe4 + Al2O3) nano-composites. Pre-milled hematite + Al powder mixture was introduced into the stir zone generated on 1050 aluminum alloy sheet by friction stir processing. Uniform and active milled powder mixture reacted with plasticized aluminum to produced Al13Fe4 + Al2O3 particles. Al13Fe4 intermetallic showed elliptical shape with a typical size of 100 nm, while nano-sized Al2O3 exhibited irregular floc-shaped particles that formed clusters with the remnant of iron oxide particles in the fine recrystallized aluminum matrix. As the milling time (1-3 h) of the introduced powder mixture increased, the volume fraction of Al13Fe4 + Al2O3 particles increased in the fabricated composite. The hardness and ultimate tensile strength of the fabricated nano-composites varied from 54.5 to 75 HV and 139 to 159 MPa, respectively; these are much higher than those of the friction stir processed base alloy (33 HV and 97 UTS). The highest hardness and strength were achieved for the nano-composite fabricated using the 3-h milled powder mixture; hard nano-sized reaction products and fine recrystallized grains of Al matrix had major and minor roles on enhancing these properties, respectively.

  17. Al-Ca and Al-Fe metal-metal composite strength, conductivity, and microstructure relationships

    SciTech Connect

    Kim, Hyong June

    2011-01-01

    Deformation processed metal-metal composites (DMMC’s) are composites formed by mechanical working (i.e., rolling, swaging, or wire drawing) of two-phase, ductile metal mixtures. Since both the matrix and reinforcing phase are ductile metals, the composites can be heavily deformed to reduce the thickness and spacing of the two phases. Recent studies have shown that heavily drawn DMMCs can achieve anomalously high strength and outstanding combinations of strength and conductivity. In this study, Al-Fe wire composite with 0.07, 0.1, and 0.2 volume fractions of Fe filaments and Al-Ca wire composite with 0.03, 0.06, and 0.09 volume fractions of Ca filaments were produced in situ, and their mechanical properties were measured as a function of deformation true strain. The Al-Fe composites displayed limited deformation of the Fe phase even at high true strains, resulting in little strengthening effect in those composites. Al-9vol%Ca wire was deformed to a deformation true strain of 13.76. The resulting Ca second-phase filaments were deformed to thicknesses on the order of one micrometer. The ultimate tensile strength increased exponentially with increasing deformation true strain, reaching a value of 197 MPa at a true strain of 13.76. This value is 2.5 times higher than the value predicted by the rule of mixtures. A quantitative relationship between UTS and deformation true strain was determined. X-ray diffraction data on transformation of Al + Ca microstructures to Al + various Al-Ca intermetallic compounds were obtained at the Advanced Photon Source at Argonne National Laboratory. Electrical conductivity was measured over a range of true strains and post-deformation heat treatment schedules.

  18. A novel TiAl3/Al2O3 composite coating on γ-TiAl alloy and evaluating the oxidation performance

    NASA Astrophysics Data System (ADS)

    Wang, Jiqiang; Kong, Lingyan; Li, Tiefan; Xiong, Tianying

    2016-01-01

    A novel TiAl3/Al2O3 composite coating was prepared on γ-TiAl alloy. The process included two steps: (1) TiAl3/Al2O3 composite powders were prepared by high energy ball milling of pure Al and nano-TiO2 powders, followed by a heat-treatment; (2) the as-prepared composite powders were deposited on γ-TiAl substrate by cold spray. The cyclic oxidation was conducted at 900 °C to test the performance of the composite coating. The results showed that the composite coating had good crack resistance and effectively decreased the oxidation rate of the substrate.

  19. Doping and compensation in Al-rich AlGaN grown on single crystal AlN and sapphire by MOCVD

    NASA Astrophysics Data System (ADS)

    Bryan, Isaac; Bryan, Zachary; Washiyama, Shun; Reddy, Pramod; Gaddy, Benjamin; Sarkar, Biplab; Breckenridge, M. Hayden; Guo, Qiang; Bobea, Milena; Tweedie, James; Mita, Seiji; Irving, Douglas; Collazo, Ramon; Sitar, Zlatko

    2018-02-01

    In order to understand the influence of dislocations on doping and compensation in Al-rich AlGaN, thin films were grown by metal organic chemical vapor deposition (MOCVD) on different templates on sapphire and low dislocation density single crystalline AlN. AlGaN grown on AlN exhibited the highest conductivity, carrier concentration, and mobility for any doping concentration due to low threading dislocation related compensation and reduced self-compensation. The onset of self-compensation, i.e., the "knee behavior" in conductivity, was found to depend only on the chemical potential of silicon, strongly indicating the cation vacancy complex with Si as the source of self-compensation. However, the magnitude of self-compensation was found to increase with an increase in dislocation density, and consequently, AlGaN grown on AlN substrates demonstrated higher conductivity over the entire doping range.

  20. KCAT, Xradia, ALS and APS Performance Summary

    SciTech Connect

    Waters, A; Martz, H; Brown, W

    2004-09-30

    At Lawrence Livermore National Laboratory (LLNL) particular emphasis is being placed on the nondestructive characterization (NDC) of components, subassemblies and assemblies of millimeter-size extent with micrometer-size features (mesoscale). These mesoscale objects include materials that vary widely in composition, density, geometry and embedded features. Characterizing these mesoscale objects is critical for corroborating the physics codes that underlie LLNL's Stockpile Stewardship mission. In this report we present results from our efforts to quantitatively characterize the performance of several x-ray systems in an effort to benchmark existing systems and to determine which systems may have the best potential for our mesoscale imaging needs.more » Several different x-ray digital radiography (DR) and computed tomography (CT) systems exist that may be applicable to our mesoscale object characterization requirements, including microfocus and synchrotron systems. The systems we have benchmarked include KCAT (LLNL developed) and Xradia {mu}XCT (Xradia, Inc., Concord, CA), both microfocus systems, and Beamline 1-ID at the Advance Photon Source (APS) and the Tomography Beamline at the Advanced Light Source (ALS), both synchrotron based systems. The ALS Tomography Beamline is a new installation, and the data presented and analyzed here is some of the first to be acquired at the facility. It is important to note that the ALS system had not yet been optimized at the time we acquired data. Results for each of these systems has been independently documented elsewhere. In this report we summarize and compare the characterization results for these systems.« less

  1. Euklid als Physiker: Die Realgeltung der Geometrie

    NASA Astrophysics Data System (ADS)

    Genz, Henning

    Es lässt sich beweisen, dass die Winkelsumme in einem ebenen, euklidischen Dreieck 180 Grad beträgt. Ebenso ergibt sich, dass die Winkelsumme in einem Dreieck auf einer Kugeloberfläche größer als 180 Grad ist. Auch der Satz des Pythagoras ist beweisbar. In allen Fällen beruhen die Beweise auf Euklids Parallelenaxiom. Das aber lässt sich nicht beweisen. Beweisbar aber ist, dass es in nicht-euklidischen Geomerien nicht gilt.

  2. Development of SiAlON materials

    NASA Technical Reports Server (NTRS)

    Layden, G. K.

    1977-01-01

    Cold pressing and sintering techniques were used to produce ceramic bodies in which the major phase was beta prime Si3-Al-O-N4 solid solution. A variety of foreign oxides were used to promote liquid phase sintering, and this resulted in the incorporation of additional solid phases in the ceramic bodies which controlled elevated temperature properties. None of the bodies studied to date exhibited both adequate high temperature mechanical properties and oxidation resistance. Criteria are suggested to guide the formulation of bodies with improved high temperature properties.

  3. Revisiting the Al/Al 2O 3 Interface: Coherent Interfaces and Misfit Accommodation

    DOE PAGES

    Pilania, Ghanshyam; Thijsse, Barend J.; Hoagland, Richard G.; ...

    2014-03-27

    We report the coherent and semi-coherent Al/α-Al 2O 3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1D) misfit dislocation model and a 2-dimensional (2D) dislocation network model have been studied. For the latter case, our analysis reveals an interface dislocation structure with a network of three sets of parallel dislocations, each with pure-edge character, giving rise to a pattern of coherent and stacking-fault-like regions atmore » the interface. Structural relaxation at elevated temperatures leads to a further change of the dislocation pattern, which can be understood in terms of a competition between the stacking fault energy and the dislocation interaction energy at the interface. In conclusion, our results are expected to serve as an input for the subsequent dislocation dynamics models to understand and predict the macroscopic mechanical behavior of Al/α-Al 2O 3 composite heterostructures.« less

  4. ICP etching of high Al mole fraction AlGaN

    NASA Astrophysics Data System (ADS)

    Meng, Zhao; Yu, Libo; Li, Xiao; Liu, Qibin; Duan, Huiqiang; Yu, Chenhui; Chen, Changqing

    2009-08-01

    The etching process has great influence on the performance of solar blind detector based on AlxGa1-xN epitaxial layers on sapphire substrate with high Al mole fraction grown by metal organic chemical vapor deposition (MOCVD) method. Traditional etching methods, including wet or reactive ion etching (RIE) are hard to achieve good result due to the high chemical-stability of AlGaN films with high Al mole fraction. In this paper, we studied on the inductively coupled plasma reactive ion etching (ICP-RIE) of high Al mole fraction AlxGa1-xN films (x>0.4) for fabricating high performance solar blind detectors. SiN was used as mask, and Cl2 and BCl3 were used as etching gas. Etching systems was selected from Oxford Inc. DC bias was controlled automatically. A 2.5:1 of selectivity on AlGaN and SiN was obtained with suitable flux and component of etching gas, RF power and ICP power. Etching velocity was adjusted mainly by RF power. The role of Ar, Cl2, and BCl3 in the etching process was also discussed.

  5. Deep SiO2 etching with Al and AlN masks for MEMS devices

    NASA Astrophysics Data System (ADS)

    Bliznetsov, Vladimir; Mao Lin, Hua; Zhang, Yue Jia; Johnson, David

    2015-08-01

    Silicon oxide-based materials such as quartz and silica are widely used in microelectromechanical systems (MEMS). One way to enhance the capability of their deep plasma etching is to increase selectivity by the use of hard masks. Although this approach was studied previously, information on the use of hard masks for the etching of silicon-oxide based materials on 200 mm substrates is scarce. We present the results of etching process development for amorphous silicon oxide using Al and AlN masks with a view of the application of the results for the etching of silica and quartz. Three gas chemistries (C4F8/O2, CF4 and SF6) and their mixtures were compared in an industrial reactive ion etch (RIE) chamber with two plasma sources. It was established that pure SF6 is the best etchant and AlN is a better mask than Al for providing higher selectivity and a sidewall angle close to vertical. A range of etching parameters for micromasking-free etching was established and etched structures of up to a 4 : 1 aspect ratio were created in 21 μm-thick oxide using the process with an etch rate of 0.32-0.36 μm min-1 and a selectivity to AlN mask of (38-49) : 1.

  6. 78 FR 6172 - In the Matter of the Designation of Ahmed Abdullah Saleh al-Khazmari al-Zahrani Also Known as Abu...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-29

    ... Matter of the Designation of Ahmed Abdullah Saleh al- Khazmari al-Zahrani Also Known as Abu Maryam al-Saudi Also Known as Ahmed Abdullah S al-Zahrani Also Known as Ahmad Abdullah Salih Al- Zahrani Also Known as Abu Maryam al-Azadi Also Known as Ahmed bin Abdullah Saleh bin al-Zahrani Also Known as Ahmed...

  7. Performance of LiAl/LiI(Al2O3)/FeS2 thermal batteries

    NASA Astrophysics Data System (ADS)

    Lin, Yung-Hsin; Yu, Kuo-Tung; Yao, Pei-Chin; Hsu, Shu-En

    Performances of the LiAl/LiI(Al2O3)/FeS2 systems with different percentages of Al2O3 in the electrolyte were tested from 460 C to 580 C at various current densities and were compared with the performance of the LiAl/LiCl-KCl/FeS2 system. The results of single-cell and battery tests indicate that the LiAl/LiI(Al2O3)/FeS2 system has a feasibility for thermal potential applications. Compared to the LiAl/LiCl-KCl/FeS2 system, the LiI(Al2O3)-based system has poorer specific conductance and lower cell potential, but longer discharge life and greater capacity. A salient feature of the LiI(Al2O3)-based system, important for reliability considerations, is its apparent greater flexibility in battery internal heat control.

  8. Characterization of thin AlSb/AlAs barriers on InAs by mid-infrared intersubband absorption measurements

    NASA Astrophysics Data System (ADS)

    Castellano, Fabrizio; Ohtani, Keita; Nevou, Laurent; Faist, Jerome

    2013-01-01

    We present mid-infrared intersubband absorption measurements on InAs/AlSb coupled-quantum-wells systems with thin AlSb barriers. The AlSb barrier width in our samples is varied between 1 and 4 monolayers, with a strained AlAs boundary layer used for strain compensation. The optical absorption energy difference between the 1-4 and 2-3 transitions is used as a measure of the barrier coupling strength and modeled by a one-band Schroedinger solver. Our results let us conclude that the composite AlSb/AlAs barrier behaves like an effective AlSb barrier with an effective thickness that does not include the last As layer. This observation must be taken into account when designing complex heterostructures relying on very thin AlSb, like in InAs/AlSb quantum cascade lasers.

  9. Surfactant Effect of in on the Movpe Growth of Al- and N-Polar AlN

    NASA Astrophysics Data System (ADS)

    Zhuang, Qinqin; Kang, Junyong; Li, Shuping; Lin, Wei

    Al- and N-polar AlN have been grown by metalorganic vapor phase epitaxy (MOVPE) with the assistance of In dopant and characterized by in situ interferometry, ellipsometry, scanning electron microscopy, atomic force microscopy, and X-ray diffractometry. The growth of Al-polar AlN is faster with smoother surfaces than the N-polar ones, which is explained by theoretical calculations. The surfactant effect of In is confirmed by improving the growth rate and surface flatness without getting into the epilayer. Additionally, In is also favorable for reducing the density of dislocations and improving the crystalline quality, especially that of Al-polar AlN. The results suggest that using In surfactant to grow the Al-polar AlN epilayer leads to a better crystal quality under proper pre-growth treatments, low- and high-temperature AlN growth conditions.

  10. Oxidation of TiAl3 and L12 Coatings on Ti-45Al-5Nb Alloy at 1173K

    NASA Astrophysics Data System (ADS)

    Nishimoto, Takumi; Kitajima, Yuri; Hayashi, Shigenari; Narita, Toshio

    Oxidation behavior of TiAl3 and L12 coated Ti-45at%Al-5at%Nb alloys at 1173K in air was investigated using mass gain measurement, field emission scanning electron microscopy, transmission electron microscopy, electron-probe microanalysis, glow discharge optical electron spectroscopy, and glancing angle X-ray diffraction analysis. The TiAl3 formed meta-stable alumina θ-Al2O3, while the oxide scale on the L12 consisted of a duplex structure with an outer rutile TiO2 and an inner α-Al2O3. During the very initial stages of oxidation both Ti and Al in the L12 coating could be oxidized, and then the faster diffusing Ti goes out to form an outer, continuous Ti-rich oxide which covers the slow growing Al2O3. In case of the TiAl3 an outer, continuous TiO2 layer was not observed because of the smaller amount of Ti in the TiAl3. It could be concluded that the outer, Ti-rich oxide enhanced a phase transformation of Al2O3 from θ to α. To elucidate the Ti effect, Ti-vapor treated TiAl3 and Ni-50at%Al were oxidized at 1173K in air, and showed formation of an α-Al2O3, in contrast to θ-Al2O3 on their bare alloys.

  11. Highly strained AlAs-type interfaces in InAs/AlSb heterostructures

    SciTech Connect

    Vallet, M., E-mail: maxime.vallet@cemes.fr; Warot-Fonrose, B.; Gatel, C.

    2016-05-23

    Spontaneously formed Al-As type interfaces of the InAs/AlSb system grown by molecular beam epitaxy for quantum cascade lasers were investigated by atomic resolution scanning transmission electron microscopy. Experimental strain profiles were compared to those coming from a model structure. High negative out-of-plane strains with the same order of magnitude as perfect Al-As interfaces were observed. The effects of the geometrical phase analysis used for strain determination were evidenced and discussed in the case of abrupt and huge variations of both atomic composition and bond length as observed in these interfaces. Intensity profiles performed on the same images confirmed that changesmore » of chemical composition are the source of high strain fields at interfaces. The results show that spontaneously assembled interfaces are not perfect but extend over 2 or 3 monolayers.« less

  12. Investigation of etching techniques for superconductive Nb/Al-Al2O3/Nb fabrication processes

    NASA Technical Reports Server (NTRS)

    Lichtenberger, A. W.; Lea, D. M.; Lloyd, F. L.

    1993-01-01

    Wet etching, CF4 and SF6 reactive ion etching (RIE), RIE/wet hybrid etching, Cl-based RIE, ion milling, and liftoff techniques have been investigated for use in superconductive Nb/Al-Al2O3/Nb fabrication processes. High-quality superconductor-insulator-superconductor (SIS) junctions have been fabricated using a variety of these etching methods; however, each technique offers distinct tradeoffs for a given process an wafer design. In particular, it was shown that SF6 provides an excellent RIE chemistry for low-voltage anisotropic etching of Nb with high selectivity to Al. The SF6 tool has greatly improved the trilevel resist junction insulation process. Excellent repeatability, selectivity with respect to quartz, and submicron resolution make Cl2 + BCl3 + CHCl3 RIE a very attractive process for trilayer patterning.

  13. Data supporting Al-Abed et al., Environ. Sci.: Nano, 2016,

    EPA Pesticide Factsheets

    Data files representing each of the Figures and Tables published in Al-Abed et al., Environ. Sci.: Nano, 2016,3, 593. The data file names identify the Figure or Table and each file contains an internal set of data definitionsThis dataset is associated with the following publication:Al-Abed, S.R., J. Virkutyte, J. Ortenzio , R.M. McCarrick, L. Degn, R. Zucker , N. Coates , K. Cleveland, H. Ma, S. Diamond, K. Dreher , and W. Boyes. Environmental aging alters AI(OH)3 coating of TiO2 nanoparticles enhancing their photocatalytic and phototoxicity activities. Environmental Science: Nano. RSC Publishing, Cambridge, UK, N/A, (2016).

  14. Communication: The Al + CO2 → AlO + CO reaction: Experiment vs. theory

    NASA Astrophysics Data System (ADS)

    Sun, Zhi; Moore, Kevin B.; Schaefer, Henry F.

    2017-11-01

    Based on their highly sophisticated crossed-beam experimental studies of the Al + CO2 → AlO + CO reaction, Honma and Hirata have directly challenged the results of earlier theoretical studies of this system. We report high level theoretical studies of this system. It is shown that, consistent with Honma-Hirata experimental conclusions, the previous theoretical prediction of a substantial barrier height for this reaction was incorrect. However, for the structures of the possible intermediates, in agreement with the 1992 theoretical study of Sakai, we find striking disagreement with the experimental conclusion that the O-C-O moiety is nearly linear. The energies of the three entrance channel intermediates lie 14.4, 15.2, and 16.4 kcal mol-1 below separated Al + CO2.

  15. FUV Reflectance of Recently Prepared Al Protected with AlF3: COR Program Technology Development

    NASA Technical Reports Server (NTRS)

    Quijada, Manuel

    2016-01-01

    Astronomical observations in the Far Ultraviolet (FUV) spectral region are some of the more challenging due to the very distant and faint objects that are typically searched for in cosmic origin studies such as origin of large scale structure, the formation, evolution, and age of galaxies and the origin of stellar and planetary systems. These challenges are driving the need to improve the performance of optical coatings over a wide spectral range that would increase reflectance in mirrors and reduced absorption in dielectric filters used in optical telescope for FUV observations. This paper will present recent advances in reflectance performance for Al+AlF3 mirrors optimized for Lyman-alpha wavelength by performing the deposition of the AlF3 overcoat at elevated substrate temperatures.

  16. Highly strained AlAs-type interfaces in InAs/AlSb heterostructures

    SciTech Connect

    Vallet, M. Warot-Fonrose, B.; Gatel, C.; Nicolai, J.; Ponchet, A.; Claveau, Y.; Combe, N.; Magen, C.; Teissier, R.; Baranov, A. N.

    2016-05-23

    Spontaneously formed Al-As type interfaces of the InAs/AlSb system grown by molecular beam epitaxy for quantum cascade lasers were investigated by atomic resolution scanning transmission electron microscopy. Experimental strain profiles were compared to those coming from a model structure. High negative out-of-plane strains with the same order of magnitude as perfect Al-As interfaces were observed. The effects of the geometrical phase analysis used for strain determination were evidenced and discussed in the case of abrupt and huge variations of both atomic composition and bond length as observed in these interfaces. Intensity profiles performed on the same images confirmed that changes of chemical composition are the source of high strain fields at interfaces. The results show that spontaneously assembled interfaces are not perfect but extend over 2 or 3 monolayers.

  17. Crystal structure and magnetic properties of Al2O3 nanoparticles by 27Al NMR data

    NASA Astrophysics Data System (ADS)

    Mikhalev, K. N.; Germov, A. Yu.; Ermakov, A. E.; Uimin, M. A.; Buzlukov, A. L.; Samatov, O. M.

    2017-03-01

    The magnetization of a series of Al2O3 with different particle sizes and their 27Al NMR spectra have been studied at room temperature. The field dependence of the magnetization demonstrated the existence of a long-range ferromagnetic order in a small part of the sample at room temperature; however, the relative volume of this contribution was very small (less than 1%), and this seems likely due to an impurity phase. The NMR spectra did not contain any lines of metallic aluminum the existence of which in these nanooxides was assumed before in a surface layer of the nanoparticles, according to the data of other techniques. The data on the phase composition and the charge distribution in different phases of the Al2O3 nanoparticles have been obtained. The change in the mean particle size (by a factor of almost three) only insignificantly changed their phase composition.

  18. The effect of Al content on the structural, mechanical, and thermal properties of B2-FeAl and D03-Fe3Al from atomistic study

    NASA Astrophysics Data System (ADS)

    Wang, Rongcheng; Zhao, Yongxin; Li, Zhuxin; Chen, Hongmei; Tao, Xiaoma; Ouyang, Yifang

    2018-02-01

    We investigate the lattice constant, formation enthalpy, elastic constants, bulk modulus, shear modulus, Young’s modulus, specific heat, thermal expansion coefficient and microhardness as a function of Al content for B2-FeAl and D03-Fe3Al using static and dynamics simulations with a long-range analytical embedded atom method (la-EAM). The lattice constants of both B2-FeAl and D03-Fe3Al crystals increase with Al content, opposite to the elastic constants, bulk modulus and shear modulus. Stoichiometric B2-FeAl has the lowest formation enthalpy and Young’s modulus. The calculation results of Gibbs free energies show that the phase transformation temperature from D03 to B2 decreases with Al content, which is in good agreement with experiments. The microhardness resulting from vacancies for B2-FeAl increases monotonically with Al content, indicating that the resultant microhardness is controlled by the vacancies, which agrees well with experiments.

  19. Genetic screening in sporadic ALS and FTD.

    PubMed

    Turner, Martin R; Al-Chalabi, Ammar; Chio, Adriano; Hardiman, Orla; Kiernan, Matthew C; Rohrer, Jonathan D; Rowe, James; Seeley, William; Talbot, Kevin

    2017-12-01

    The increasing complexity of the genetic landscape in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) presents a significant resource and physician training challenge. At least 10% of those diagnosed with ALS or FTD are known to carry an autosomal dominant genetic mutation. There is no consensus on what constitutes a positive family history, and ascertainment is unreliable for many reasons. However, symptomatic individuals often wish to understand as much as possible about the cause of their disease, and to share this knowledge with their family. While the right of an individual not to know is a key aspect of patient autonomy, and despite the absence of definitive therapy, many newly diagnosed individuals are likely to elect for genetic testing if offered. It is incumbent on the practitioner to ensure that they are adequately informed, counselled and supported in this decision. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. CarbAl Heat Transfer Material

    NASA Technical Reports Server (NTRS)

    Fink, Richard

    2015-01-01

    The increasing use of power electronics, such as high-current semiconductor devices and modules, within space vehicles is driving the need to develop specialty thermal management materials in both the packaging of these discrete devices and the packaging of modules consisting of these device arrays. Developed by Applied Nanotech, Inc. (ANI), CarbAl heat transfer material is uniquely characterized by its low density, high thermal diffusivity, and high thermal conductivity. Its coefficient of thermal expansion (CTE) is similar to most power electronic materials, making it an effective base plate substrate for state-of-the-art silicon carbide (SiC) super junction transistors. The material currently is being used to optimize hybrid vehicle inverter packaging. Adapting CarbAl-based substrates to space applications was a major focus of the SBIR project work. In Phase I, ANI completed modeling and experimentation to validate its deployment in a space environment. Key parameters related to cryogenic temperature scaling of CTE, thermal conductivity, and mechanical strength. In Phase II, the company concentrated on improving heat sinks and thermally conductive circuit boards for power electronic applications.

  1. Hybrid density functional study on the photocatalytic properties of AlN/MoSe2, AlN/WS2, and AlN/WSe2 heterostructures

    NASA Astrophysics Data System (ADS)

    Wang, Guangzhao; Dang, Suihu; Zhang, Peng; Xiao, Shuyuan; Wang, Cuihong; Zhong, Mingmin

    2018-01-01

    Hybrid density functional has been adopted to theoretically investigate the structural, electronic, and optical properties of AlN/MoSe2, AlN/WS2, and AlN/WSe2 heterostructures with the consideration of effects of strains and pH so as to explore their potential visible light photocatalytic activities for water splitting. AlN/MoSe2, AlN/WS2, and AlN/WSe2 heterostructures with proper strains are energetically favorable due to the good lattice mismatch and the interface adhesion energies between the constituent monolayers. The charge accumulation/depletion around the interfaces of these heterostructures are beneficial for the generation and separation of photogenerated carriers, which is also favorable for improving the photocatalytic activities. Through adjusting the strains and the pH of the electrolyte, the AlN/MoSe2, AlN/WS2, and AlN/WSe2 heterostructures could own suitable bandgaps for absorbing visible light and appropriate band edge positions with respect to water redox levels for the spontaneous generation of hydrogen and oxygen. The band edge positions of AlN/MoSe2, AlN/WS2, and AlN/WSe2 heterostructures are thermodynamically feasible for over water splitting when the pHs of the electrolyte are respectively around 13, in the range of 4.5–8.1, and greater than 10.7. These findings pave a way to design the efficient AlN-based heterostructures for visible light photocatalytic water splitting.

  2. ALS clinical trials: do enrolled patients accurately represent the ALS population?

    PubMed

    Chiò, A; Canosa, A; Gallo, S; Cammarosano, S; Moglia, C; Fuda, G; Calvo, A; Mora, G

    2011-10-11

    To assess the effect of eligibility criteria in amyotrophic lateral sclerosis (ALS) clinical trials on the representativeness of the enrolled population. Patients enrolled in 8 placebo-controlled clinical trials in our ALS center from 2003 to 2008 were compared 1) to the patients included a prospective epidemiologic register (Piemonte and Valle d'Aosta register for ALS, PARALS) in the same period and 2) the subset of PARALS patients who met the usual criteria for inclusion in clinical trials (PARALS-ct) (definite, probable, probable laboratory-supported ALS; age between 18 and 75 years; disease duration <36 months; vital capacity at diagnosis ≥70%; score ≥3 at the items swallowing and respiratory insufficiency at the Amyotrophic Lateral Sclerosis Functional Rating Scale-revised scale; riluzole therapy). A total of 164 patients were enrolled in 8 different clinical trials. The PARALS cohort included 813 patients, of whom 539 (66.3%) met the entry criteria for clinical trials. Patients enrolled in clinical trials were different from both epidemiologic cohorts, since they were younger, had a longer diagnostic delay, and were more likely to have a spinal onset, and to be men. Tracheostomy-free survival was significantly longer in the group of patients enrolled in clinical trials (median survival time, trial patients, 3.9 years [95% confidence interval (CI) 3.4-4.4]; PARALS, 2.6 [2.4-2.8]; PARALS-ct, 2.9 [2.7-3.1]). Patients enrolled in clinical trials do not satisfactorily represent the ALS population; consequently, the findings of ALS trials lack of external validity (generalizability). Efforts should be made to improve patients' recruitment in trials, particularly enrolling incident rather than prevalent cases.

  3. Ion-exchange and potentiometric characterization of Al-cystine and Al-cysteine complexes.

    PubMed

    Bohrer, Denise; Polli, Vania Gabbi; Cícero do Nascimento, Paulo; Mendonça, Jean Karlo A; de Carvalho, Leandro Machado; Pomblum, Solange Garcia

    2006-11-01

    The interaction between aluminium and cysteine and cystine was evaluated by means of ion-exchange experiments and potentiometry. Ion-exchange experiments included other ligands with affinity for aluminium and two kinds of resins, either a Na+ -form or an Al3+ -form exchanger. The ability of the ligands to keep aluminium in solution in the presence of the Na+ exchanger or to withdraw it from the Al3+ -form resin was evaluated. Aluminium quantification was carried out by either graphite-furnace or flame atomic absorption spectrometry. Aluminium extraction isotherms were linearised using the Scatchard plot, and stability constants were obtained from the curves' slopes. The experiments showed that the ability of the ligands to withdraw aluminium from the Al3+ -form resin increased following the order cysteine < oxalate < citrate = cystine < nitrilotriacetic acid < ethylenediaminetetraacetic acid. Potentiometric titrations, carried out in aqueous solution with constant ionic strength and temperature, showed that the predominant species in solution have a metal-ligand proportion of 1:1 for both amino acids. The main species are Al(OH)3L, with log K of 6.2 for cysteine, and AlL and Al(OH)L, with log K of 10.3 and 1.7, respectively, for cystine. Stability constants obtained from the Scatchard plots showed a linear correlation with the stability constants obtained by potentiometry for cystine and cysteine in this work and those collected from the literature for the other ligands. These results show that cysteine and cystine extract and maintain aluminium in solution, which may explain elevated concentrations of aluminium in parenteral nutrition solutions containing these amino acids.

  4. Acoustic resonator with Al electrodes on an AlN layer and using a GaAs substrate

    DOEpatents

    Kline, Gerald R.; Lakin, Kenneth M.

    1985-12-03

    A method of fabricating an acoustic wave resonator wherein all processing steps are accomplished from a single side of said substrate. The method involves deposition of a multi-layered Al/AlN structure on a GaAs substrate followed by a series of fabrication steps to define a resonator from said composite. The resulting resonator comprises an AlN layer between two Al layers and another layer of AlN on an exterior of one of said Al layers.

  5. Tuning of reflectance transition position of Al-AlN cermet solar selective absorbing coating by simulating

    NASA Astrophysics Data System (ADS)

    Ning, Yuping; Wang, Wenwen; Sun, Ying; Wu, Yongxin; Man, Hongliang; Wang, Cong; Zhao, Shuxi; Tomasella, Eric; Bousquet, Angélique; Zhang, Yong

    2017-01-01

    The reflectance spectra of the Al/double cermet Al-AlN/AlOxNy solar selective absorbing coating are simulated. Two methods have been found to effectively tune the position of reflectance transition of the Al-AlN cermet solar selective absorbing coating, which is crucial to obtain a low emittance at elevated temperature. The position of reflectance transition is mainly determined by the high metal volume fraction (HMVF) cermet layer. It is effectively tuned to shift to lower wavelength by reducing the metal volume fraction or the thickness of the HMVF layer. This provides easy ways to tune the position of reflectance transition.

  6. Vanishing quasiparticle density in a hybrid Al/Cu/Al single-electron transistor

    NASA Astrophysics Data System (ADS)

    Saira, O.-P.; Kemppinen, A.; Maisi, V. F.; Pekola, J. P.

    2012-01-01

    The achievable fidelity of many nanoelectronic devices based on superconducting aluminum is limited by either the density of residual nonequilibrium quasiparticles nqp or the density of quasiparticle states in the gap, characterized by Dynes parameter γ. We infer upper bounds nqp<0.033μm-3 and γ<1.6×10-7 from transport measurements performed on Al/Cu/Al single-electron transistors, improving previous results by an order of magnitude. Owing to efficient microwave shielding and quasiparticle relaxation, a typical number of quasiparticles in the superconducting leads is zero.

  7. Comments to Nordmo et al.'s article: effect of hardiness.

    PubMed

    Lucavei, Júlia; Pougnet, Laurence; Dewitte, Jean-Dominique; Loddé, Brice; Pougnet, Richard

    2017-01-01

    We would like to comment on Nordmo et al.'s article on hardiness among Norwegian Royal Navy seamen. The article is very interesting. Understanding the sleep disorders of the military can indeed make it possible to favour the preservation of their health and their competencies. The authors have highlighted the limitations of their study. They will take into account the sleep disorder factors already described in literature, such as: noise, comfort on board, shift organisations, etc. We would like to make two comments: on the one hand, highlight another limit to help future studies; on the other hand, open another perspective of prevention, not described in this article.

  8. 78 FR 76054 - Establishment of Class E Airspace; Chatom, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-16

    ... Airspace at Chatom, AL, to accommodate the Area Navigation (RNAV) Global Positioning System (GPS) Standard... Airport, Chatom, AL, providing the controlled airspace required to accommodate the new RNAV (GPS) Standard...

  9. Abrupt Schottky Junctions in Al/Ge Nanowire Heterostructures.

    PubMed

    Kral, S; Zeiner, C; Stöger-Pollach, M; Bertagnolli, E; den Hertog, M I; Lopez-Haro, M; Robin, E; El Hajraoui, K; Lugstein, A

    2015-07-08

    In this Letter we report on the exploration of axial metal/semiconductor (Al/Ge) nanowire heterostructures with abrupt interfaces. The formation process is enabled by a thermal induced exchange reaction between the vapor-liquid-solid grown Ge nanowire and Al contact pads due to the substantially different diffusion behavior of Ge in Al and vice versa. Temperature-dependent I-V measurements revealed the metallic properties of the crystalline Al nanowire segments with a maximum current carrying capacity of about 0.8 MA/cm(2). Transmission electron microscopy (TEM) characterization has confirmed both the composition and crystalline nature of the pure Al nanowire segments. A very sharp interface between the ⟨111⟩ oriented Ge nanowire and the reacted Al part was observed with a Schottky barrier height of 361 meV. To demonstrate the potential of this approach, a monolithic Al/Ge/Al heterostructure was used to fabricate a novel impact ionization device.

  10. Growth and Oxidation of Thin Film Al(2)Cu

    SciTech Connect

    SON,KYUNG-AH; MISSERT,NANCY A.; BARBOUR,J. CHARLES

    2000-01-18

    Al{sub 2}Cu thin films ({approx} 382 nm) are fabricated by melting and resolidifying Al/Cu bilayers in the presence of a {micro} 3 nm Al{sub 2}O{sub 3} passivating layer. X-ray Photoelectron Spectroscopy (XPS) measures a 1.0 eV shift of the Cu2p{sub 3/2} peak and a 1.6 eV shift of the valence band relative to metallic Cu upon Al{sub 2}Cu formation. Scanning Electron microscopy (SEM) and Electron Back-Scattered Diffraction (EBSD) show that the Al{sub 2}Cu film is composed of 30-70 {micro}m wide and 10-25 mm long cellular grains with (110) orientation. The atomic composition of the film as estimated by Energy Dispersivemore » Spectroscopy (EDS) is 67 {+-} 2% Al and 33 {+-} 2% Cu. XPS scans of Al{sub 2}O{sub 3}/Al{sub 2}Cu taken before and after air exposure indicate that the upper Al{sub 2}Cu layers undergo further oxidation to Al{sub 2}O{sub 3} even in the presence of {approx} 5 nm Al{sub 2}O{sub 3}. The majority of Cu produced from oxidation is believed to migrate below the Al{sub 2}O{sub 3} layers, based upon the lack of evidence for metallic Cu in the XPS scans. In contrast to Al/Cu passivated with Al{sub 2}O{sub 3}, melting/resolidifying the Al/Cu bilayer without Al{sub 2}O{sub 3} results in phase-segregated dendritic film growth.« less

  11. Mechanisms of elevated-temperature deformation in the B2 aluminides NiAl and CoAl

    NASA Technical Reports Server (NTRS)

    Yaney, D. L.; Nix, W. D.

    1988-01-01

    A strain rate change technique, developed previously for distinguishing between pure-metal and alloy-type creep behavior, was used to study the elevated-temperature deformation behavior of the intermetallic compounds NiAl and CoAl. Tests on NiAl were conducted at temperatures between 1100 and 1300 K while tests on CoAl were performed at temperatures ranging from 1200 to 1400 K. NiAl exhibits pure-metal type behavior over the entire temperature range studied. CoAl, however, undergoes a transition from pure-metal to alloy-type deformation behavior as the temperature is decreased from 1400 to 1200 K. Slip appears to be inherently more difficult in CoAl than in NiAl, with lattice friction effects limiting the mobility of dislocations at a much higher tmeperature in CoAl than in NiAl. The superior strength of CoAl at elevated temperatures may, therefore, be related to a greater lattice friction strengthening effect in CoAl than in NiAl.

  12. Mechanochemical Behavior of NiO-Al-Fe Powder Mixtures to Produce (Ni, Fe)3Al-Al2O3 Nanocomposite Powder

    NASA Astrophysics Data System (ADS)

    Adabavazeh, Z.; Karimzadeh, F.; Enayati, M. H.

    2012-09-01

    (Ni, Fe)3Al-30 vol pct Al2O3 nanocomposite powder was synthesized by mechanochemical reaction of Fe-NiO-Al powder mixtures. Structural evolution during mechanical alloying was studied by employing X-ray diffractometry (XRD), differential thermal analysis (DTA), and transmission electron microscopy (TEM). After 78 minutes of milling, the (Ni, Fe)3Al-30 vol pct Al2O3 nanocomposite can be synthesized by reaction 3Fe + 7Al + 6NiO with a combustion mode. DTA results revealed that milling for 60 minutes decreases the temperature of reaction from 1040 K to 898 K (767 °C to 625 °C). TEM images corroborate a homogenous dispersion of reinforcements in the matrix of the nanocomposite proving that the reduction in the crystallite size of both reinforcements and matrix is within the nanometer range.

  13. Research of the structural and electronic properties of VN/AlN/VN and AlN/VN/AlN based on DFT calculation

    NASA Astrophysics Data System (ADS)

    Díaz F, J. H.; Espitia R, M. J.; Rodriguez Martínez, J. A.

    2016-08-01

    We investigated the structural, electronic, and magnetic properties of AlN/VN/AlN and VN/AlN/VN interlayers in the wurtzite structure, via first-principles calculations using the psuedopotential method within density functional theory (DFT) as implemented in the Quantum ESPRESSO code. The total energy calculation showed that the VN/AlN/VN interlayer is energetically more favorable than the AlN/VN/AlN one. Analysis of the density of states showed that the interlayers exhibit a metallic behavior that essentially comes from the hybridization and polarization of states V-d and N-p across the Fermi level. The interlayers exhibit magnetic properties, with a magnetic moment of 4μβ/cell. Due to these properties, the superlattices can potentially be used in the field of spintronics.

  14. Mixing of Al into uranium silicides reactor fuels

    SciTech Connect

    Ding, F.R.; Birtcher, R.C.; Kestel, B.J.; Baldo, P.M.

    1996-11-01

    SEM observations have shown that irradiation induced interaction of the aluminum cladding with uranium silicide reactor fuels strongly affects both fission gas and fuel swelling behaviors during fuel burn-up. The authors have used ion beam mixing, by 1.5 MeV Kr, to study this phenomena. RBS and the {sup 27}Al(p, {gamma}) {sup 28}Si resonance nuclear reaction were used to measure radiation induced mixing of Al into U{sub 3}Si and U{sub 3}Si{sub 2} after irradiation at 300 C. Initially U mixes into the Al layer and Al mixes into the U{sub 3}Si. At a low dose, the Al layer is converted into UAl{sub 4} type compound while near the interface the phase U(Al{sub .93}Si{sub .07}){sub 3} grows. Under irradiation, Al diffuses out of the UAl{sub 4} surface layer, and the lower density ternary, which is stable under irradiation, is the final product. Al mixing into U{sub 3}Si{sub 2} is slower than in U{sub 3}Si, but after high dose irradiation the Al concentration extends much farther into the bulk. In both systems Al mixing and diffusion is controlled by phase formation and growth. The Al mixing rates into the two alloys are similar to that of Al into pure uranium where similar aluminide phases are formed.

  15. Laser ablation of Al-Ni alloys and multilayers

    NASA Astrophysics Data System (ADS)

    Roth, Johannes; Trebin, Hans-Rainer; Kiselev, Alexander; Rapp, Dennis-Michael

    2016-05-01

    Laser ablation of Al-Ni alloys and multilayers has been studied by molecular dynamics simulations. The method was combined with a two-temperature model to describe the interaction between the laser beam, the electrons, and the atoms. As a first step, electronic parameters for the alloys had to be found and the model developed originally for pure metals had to be generalized to multilayers. The modifications were verified by computing melting depths and ablation thresholds for pure Al and Ni. Here known data could be reproduced. The improved model was applied to the alloys Al_3Ni, AlNi and AlNi_3. While melting depths and ablation thresholds for AlNi behave unspectacular, sharp drops at high fluences are observed for Al_3Ni and AlNi_3. In both cases, the reason is a change in ablation mechanism from phase explosion to vaporization. Furthermore, a phase transition occurs in Al_3Ni. Finally, Al layers of various thicknesses on a Ni substrate have been simulated. Above threshold, 8 nm Al films are ablated as a whole while 24 nm Al films are only partially removed. Below threshold, alloying with a mixture gradient has been observed in the thin layer system.

  16. MCrAlY bond coat with enhanced Yttrium layer

    DOEpatents

    Jablonski, Paul D; Hawk, Jeffrey A

    2015-04-21

    One or more embodiments relates to an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y--Al.sub.2O.sub.3 layer. The MCrAlY layer is comprised of a .gamma.-M solid solution, a .beta.-MAl intermetallic phase, and Y-type intermetallics. The Y--Al.sub.2O.sub.3 layer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the Al.sub.2O.sub.3 lattice. Both the MCrAlY layer and the Y--Al.sub.2O.sub.3 layer have a substantial absence of Y--Al oxides, providing advantage in the maintainability of the Yttrium reservoir within the MCrAlY bulk. The MCrAlY bond coat may be fabricated through application of a Y.sub.2O.sub.3 paste to an MCrAlY material, followed by heating in a non-oxidizing environment.

  17. MCrAlY bond coat with enhanced Yttrium layer

    SciTech Connect

    Jablonski, Paul D; Hawk, Jeffrey A

    2015-04-21

    One or more embodiments relates to an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y--Al.sub.2O.sub.3 layer. The MCrAlY layer is comprised of a .gamma.-M solid solution, a .beta.-MAl intermetallic phase, and Y-type intermetallics. The Y--Al.sub.2O.sub.3 layer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the Al.sub.2O.sub.3 lattice. Both the MCrAlY layer and the Y--Al.sub.2O.sub.3 layer have a substantial absence of Y--Al oxides, providing advantage in the maintainability of the Yttrium reservoir within the MCrAlY bulk. The MCrAlY bond coat may be fabricated through application of a Y.sub.2O.sub.3 paste to an MCrAlY material, followed bymore » heating in a non-oxidizing environment.« less

  18. Al-Qaeda: Center of Gravity and Decisive Points

    DTIC Science & Technology

    2003-04-07

    implementing changes in the curriculum, which should vilify Al-Qaeda and the use of terrorism, showing how they betray the teachings of Mohammad ...no footprint. Members of Al-Qaeda pledge an oath of allegiance called bayat . Al-Qaeda kills those suspected of collaborating with the enemy and

  19. Density functional theory study and kinetic analysis of the formation mechanism of Al 30O 8(OH) 56(H 2O) 2618+ (Al 30) in aqueous solution

    NASA Astrophysics Data System (ADS)

    Yang, Wenjing; Qian, Zhaosheng; Lu, Bangmei; Zhang, Jing; Bi, Shuping

    2010-02-01

    The formation mechanism of Al 30O 8(OH) 56(H 2O) 2618+ (Al 30) has been investigated by the density functional theory based on the supermolecule model and kinetic analysis on the 27Al nuclear magnetic resonance (NMR) experimental results in monitoring Al 30 synthesis process. The theoretical chemistry calculations on the four possible schemes show that δ-Na-Al 13 is the reasonable intermediate followed by the substitution of Na with Al to form δ-Al 14, and Na + plays an important role in stabilizing the intermediate (δ-Na-Al 13) in the transformation. The kinetic analysis on the 27Al NMR experimental data indicates that ɛ-Al 13 decomposes and isomerizes in the formation of Al 30, while Al monomers facilitate the decomposition of ɛ-Al 13 and so the isomerization of ɛ-isomers to δ-isomers effectively. The favorable formation mechanism of Al 30 includes three steps: (1) ɛ-Al 13 decomposes and rearranges into the isomer δ-Al 13; (2) Na + reacts with δ-Al 13 to stabilize the intermediate δ-Na-Al 13, followed by Al monomers replacing Na to form δ-Al 14; (3) δ-Al 14 reacts with the Al monomers in the solution to finally form Al 30. Both Al monomers and Na + are important in the transformation. Al monomers are the basic building units and helpful to the isomerization while Na + can well stabilize the isomer δ-Al 13 to yield intermediate δ-Na-Al 13. The results also show that other isomers of ɛ-Al 13 (β-Al 13 and α-Al 13) form in the formation of Al 30, and their calculated 27Al NMR tetrahedral resonance shifts are consistent with the experimental 27Al NMR tetrahedral signals in the preparation process of Al 30.

  20. Screw dislocation-induced growth spirals as emissive exciton localization centers in Al-rich AlGaN/AlN quantum wells

    SciTech Connect

    Funato, Mitsuru, E-mail: funato@kuee.kyoto-u.ac.jp; Banal, Ryan G.; Kawakami, Yoichi

    2015-11-15

    Screw dislocations in Al-rich AlGaN/AlN quantum wells cause growth spirals with an enhanced Ga incorporation, which create potential minima. Although screw dislocations and their surrounding potential minima suggest non-radiative recombination processes within growth spirals, in reality, screw dislocations are not major non-radiative sinks for carriers. Consequently, carriers localized within growth spirals recombine radiatively without being captured by non-radiative recombination centers, resulting in intense emissions from growth spirals.

  1. Ab initio molecular dynamics of Al irradiation-induced processes during Al{sub 2}O{sub 3} growth

    SciTech Connect

    Music, Denis; Nahif, Farwah; Friederichsen, Niklas; Schneider, Jochen M.; Sarakinos, Kostas

    2011-03-14

    Al bombardment induced structural changes in {alpha}-Al{sub 2}O{sub 3} (R-3c) and {gamma}-Al{sub 2}O{sub 3} (Fd-3m) were studied using ab initio molecular dynamics. Diffusion and irradiation damage occur for both polymorphs in the kinetic energy range from 3.5 to 40 eV. However, for {gamma}-Al{sub 2}O{sub 3}(001) subplantation of impinging Al causes significantly larger irradiation damage and hence larger mobility as compared to {alpha}-Al{sub 2}O{sub 3}. Consequently, fast diffusion along {gamma}-Al{sub 2}O{sub 3}(001) gives rise to preferential {alpha}-Al{sub 2}O{sub 3}(0001) growth, which is consistent with published structure evolution experiments.

  2. Properties of NiAl and Ni-Al-N thin films deposited by closed field unbalanced magnetron sputter ion plating using elemental Ni and Al targets.

    PubMed

    Baig, M N; Ahmed, W; Khalid, F A; Said, R M; McLaughlin, J

    2009-07-01

    Approximately 1 microm thick NiAl and Ni-Al-N thin films have been deposited from individual elemental Ni (99.5% pure) and Al (99.5% pure) targets onto glass and stainless steel 316 substrates using closed field unbalanced magnetron sputter ion platting (CFUBMSIP) process. The films have been characterized using stylus profilometry, energy dispersive spectroscopy (EDAX), X-ray diffractometry (XRD) and atomic force microscopy (AFM). The X-ray diffraction patterns of both types of thin films produced confirmed the formation of beta-NiAl phase. The EDAX results revealed that all of the NiAl thin films produced exhibited the near equiatomic NiAl phase with the best results given by the one deposited using 300 Watts DC power for Ni and 400 Watts DC power for Al targets respectively. However, the Ni-Al-N thin films showed a Ni-rich NiAl phase. AFM results of both types of films produced carried out on glass samples exhibited that the coatings have quite a smooth surface with surface roughness in nanometres range.

  3. Unifying cluster-based structure models of decagonal Al-Co-Ni, Al-Co-Cu and Al-Fe-Ni.

    PubMed

    Deloudi, Sofia; Fleischer, Frank; Steurer, Walter

    2011-02-01

    The geometrical building principles of Al-based decagonal quasicrystals and their approximants are discussed from a cluster-based approach. Our investigations cover 11 modifications with two- or four-layer periodicity in the systems Al-Co-Ni, Al-Co-Cu and Al-Fe-Ni. We identified a cluster that leads to a unifying view of all these phases. This unit cluster has ~20 Å diameter, four-layer periodicity along its tenfold axis and rod symmetry group p102m. The models obtained are in agreement with all the electron-density maps and electron-microscopy images available.

  4. A sulfur segregation study of PWA 1480, NiCrAl, and NiAl alloys

    NASA Technical Reports Server (NTRS)

    Jayne, D. T.; Smialek, J. L.

    1993-01-01

    Some nickel based superalloys show reduced oxidation resistance from the lack of an adherent oxide layer during high temperature cyclic oxidation. The segregation of sulfur to the oxide-metal interface is believed to effect oxide adhesion, since low sulfur alloys exhibit enhanced adhesion. X ray Photoelectron Spectroscopy (XPS) was combined with an in situ sample heater to measure sulfur segregation in NiCrAl, PWA 1480, and NiAl alloys. The polished samples with a 1.5 to 2.5 nm (native) oxide were heated from 650 to 1100 C with hold times up to 6 hr. The sulfur concentration was plotted as a function of temperature versus time at temperature. One NiCrAl sulfur study was performed on the same casting used by Browning to establish a base line between previous Auger Electron Spectroscopy (AES) results and the XPS results of this study. Sulfur surface segregation was similar for PWA 1480 and NiCrAl and reached a maximum of 30 at% at 800 to 850 C. Above 900 C the sulfur surface concentration decreased to about 3 at% at 1100 C. These results are contrasted to the minimal segregation observed for low sulfur hydrogen annealed materials which exhibit improved scale adhesion.

  5. High Temperature Mechanical Characterization and Analysis of Al2O3 /Al2O3 Composition

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Jaskowiak, Martha H.

    1999-01-01

    Sixteen ply unidirectional zirconia coated single crystal Al2O3 fiber reinforced polycrystalline Al2O3 was tested in uniaxial tension at temperatures to 1400 C in air. Fiber volume fractions ranged from 26 to 31%. The matrix has primarily open porosity of approximately 40%. Theories for predicting the Young's modulus, first matrix cracking stress, and ultimate strength were applied and evaluated for suitability in predicting the mechanical behavior of Al2O3/Al2O3 composites. The composite exhibited pseudo tough behavior (increased area under the stress/strain curve relative to monolithic alumina) from 22 to 1400 C. The rule-of-mixtures provides a good estimate of the Young's modulus of the composite using the constituent properties from room temperature to approximately 1200 C for short term static tensile tests in air. The ACK theory provides the best approximation of the first matrix cracking stress while accounting for residual stresses at room temperature. Difficulties in determining the fiber/matrix interfacial shear stress at high temperatures prevented the accurate prediction of the first matrix cracking stress above room temperature. The theory of Cao and Thouless, based on Weibull statistics, gave the best prediction for the composite ultimate tensile strength.

  6. Aesthetic Leadership (AL): Development and Implementation of Aesthetic Leadership Scale (ALS) of the School Directors

    ERIC Educational Resources Information Center

    Polat, Soner; Oztoprak-Kavak, Zehra

    2011-01-01

    This study aims to develop a scale for measuring the aesthetic leadership (AL) characteristics of the school directors and to show that it can be applicable. The population of the study is composed of the teachers who are on duty in the elementary, secondary and high schools located in Izmit, Kocaeli. Sample of this descriptive study comprises 400…

  7. Environmental quality assessment of groundwater resources in Al Jabal Al Akhdar, Sultanate of Oman

    NASA Astrophysics Data System (ADS)

    Al-Kalbani, Mohammed Saif; Price, Martin F.; Ahmed, Mushtaque; Abahussain, Asma; O'Higgins, Timothy

    2017-11-01

    The research was conducted to assess the quality of groundwater resources of Al Jabal Al Akhdar, Oman. 11 drinking water sources were sampled during summer and winter seasons during 2012-2013 to evaluate their physico-chemical quality indicators; and assess their suitability for drinking and other domestic purposes. Sample collection, handling and processing followed the standard methods recommended by APHA and analyzed in quality assured laboratories using appropriate analytical methods and instrumental techniques. The results show that the quality parameters in all drinking water resources are within the permissible limits set by Omani and WHO standards; and the drinking water quality index is good or medium in quality based on NFS-WQI classification criteria, indicating their suitability for human consumption. There is an indication of the presence of high nitrate concentrations in some groundwater wells, which require more investigations and monitoring program to be conducted on regular basis to ensure good quality water supply for the residents in the mountain. The trilinear Piper diagram shows that most of the drinking water resources of the study area fall in the field of calcium and bicarbonate type with some magnesium bicarbonate type indicating that most of the major ions are natural in origin due to the geology of the region. This study is a first step towards providing indicators on groundwater quality of this fragile mountain ecosystem, which will be the basis for future planning decisions on corrective demand management measures to protect groundwater resources of Al Jabal Al Akhdar.

  8. Microstructure and Mechanical Properties of Hypereutectic Al-Si/AlNp Composite

    NASA Astrophysics Data System (ADS)

    Park, Seulki; Choi, Jinmyung; Park, Bonggyu; Park, Ikmin; Park, Yongho; Kim, Yongjin

    Hypereutectic Al-Si alloys with fine and evenly distributed Si precipitates have superior mechanical properties In this study, hypereutectic Al-Si alloy powders which contained 15 and 20wt% Si were prepared by a gas atomization process. 1, 3 and 5wt% AlN particles were blended with the Al-Si alloy powders using turbular mixer. The mixture was consolidated by Hot Press at 550°C for 1h under 60MPa. Relative density of the sintered samples was about 98% of theoretical density. This study was investigated by two ways. One is the effect of reinforcement weight fraction and the other is the effect of Silicon contents on the mechanical properties of the composite. Microstructural characterization and phase evaluation were carried out using X-ray Diffraction, Scanning Electron Microscopy equipped with Energy Dispersive Spectrometer. The results showed that the smaller the reinforcement particle size was and the better its distribution was, the higher ultimate tensile strength and hardness were.

  9. Cyclic Oxidation of FeCrAlY/Al2O3 Composites

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.; Draper, Susan L.; Barrett, Charles A.

    1999-01-01

    Three-ply FeCrAlY/Al2O3 composites and FeCrAlY matrix-only samples were cyclically oxidized at 1000 C and 1100 C for up to 1000 1-hr cycles. Fiber ends were exposed at the ends of the composite samples. Following cyclic oxidation, cracks running parallel to and perpendicular to the fibers were observed on the large surface of the composite. In addition, there was evidence of increased scale damage and spallation around the exposed fiber ends, particularly around the middle ply fibers. This damage was more pronounced at the higher temperature. The exposed fiber ends showed cracking between fibers in the outer plies, occasionally with Fe and Cr-rich oxides growing out of the cracks. Large gaps developed at the fiber/matrix interface around many of the fibers, especially those in the outer plies. Oxygen penetrated many of these gaps resulting in significant oxide formation at the fiber/matrix interface far within the composite sample. Around several fibers, the matrix was also internally oxidized showing Al2O3 precipitates in a radial band around the fibers. The results show that these composites have poor cyclic oxidation resistance due to the CTE mismatch and inadequate fiber/matrix bond strength at temperatures of 1000 C and above.

  10. Structure of oxides prepared by decomposition of layered double Mg–Al and Ni–Al hydroxides

    SciTech Connect

    Cherepanova, Svetlana V.; Leont’eva, Natalya N.; Arbuzov, Aleksey B.; Drozdov, Vladimir A.; Belskaya, Olga B.; Antonicheva, Nina V.

    2015-05-15

    Abstracts: Thermal decomposition of Mg–Al and Ni–Al layered double hydroxides LDH at temperatures lower than 800 °C leads to the formation of oxides with different structures. Mg–Al oxide has a very defective structure and consists of octahedral layers as in periclase MgO and mixed octahedral–tetrahedral layers as in spinel MgAl{sub 2}O{sub 4}. Mixed Ni–Al oxide has a sandwich-like structure, consisting of a core with Al-doped NiO-like structure and some surface layers with spinel NiAl{sub 2}O{sub 4} structure epitaxial connected with the core. Suggested models were verified by simulation of X-ray diffraction patterns using DIFFaX code, as well as HRTEM, IR-, UV-spectroscopies, and XPS. - Graphical abstract: In the Mg–Al layered double hydroxide Al{sup 3+} ions migrate into interlayers during decomposition. The Mg–Al oxide represents sequence of octahedral and octahedral–tetrahedral spinel layers with vacancies. The Ni–Al oxide has a sandwich-like structure with NiO-like core and surface spinel layers as a result of migration of Al{sup 3+} ions on the surface. The models explain the presence and absence of “memory effect” for the Mg–Al and Ni–Al oxides, respectively. - Highlights: • We study products of Mg(Ni)–Al LDH decomposition by calcination at 500(400)–800 °C. • In Mg–Al/Ni–Al LDH Al ions migrate into interlayers/on the surface during decomposition. • Mg–Al oxide represents sequence of periclase- and spinel-like layers with vacancies. • Ni–Al oxide has a sandwich-like structure with NiO-like core and surface spinel layers. • The models explain the presence/absence of “memory effect” for Mg–Al/Ni–Al oxides.

  11. Structure of oxides prepared by decomposition of layered double Mg–Al and Ni–Al hydroxides

    SciTech Connect

    Cherepanova, Svetlana V.; Novosibirsk State University, Novosibirsk; Leont’eva, Natalya N., E-mail: n_n_leonteva@list.ru

    2015-05-15

    Abstracts: Thermal decomposition of Mg–Al and Ni–Al layered double hydroxides LDH at temperatures lower than 800 °C leads to the formation of oxides with different structures. Mg–Al oxide has a very defective structure and consists of octahedral layers as in periclase MgO and mixed octahedral–tetrahedral layers as in spinel MgAl{sub 2}O{sub 4}. Mixed Ni–Al oxide has a sandwich-like structure, consisting of a core with Al-doped NiO-like structure and some surface layers with spinel NiAl{sub 2}O{sub 4} structure epitaxial connected with the core. Suggested models were verified by simulation of X-ray diffraction patterns using DIFFaX code, as well as HRTEM, IR-,more » UV-spectroscopies, and XPS. - Graphical abstract: In the Mg–Al layered double hydroxide Al{sup 3+} ions migrate into interlayers during decomposition. The Mg–Al oxide represents sequence of octahedral and octahedral–tetrahedral spinel layers with vacancies. The Ni–Al oxide has a sandwich-like structure with NiO-like core and surface spinel layers as a result of migration of Al{sup 3+} ions on the surface. The models explain the presence and absence of “memory effect” for the Mg–Al and Ni–Al oxides, respectively. - Highlights: • We study products of Mg(Ni)–Al LDH decomposition by calcination at 500(400)–800 °C. • In Mg–Al/Ni–Al LDH Al ions migrate into interlayers/on the surface during decomposition. • Mg–Al oxide represents sequence of periclase- and spinel-like layers with vacancies. • Ni–Al oxide has a sandwich-like structure with NiO-like core and surface spinel layers. • The models explain the presence/absence of “memory effect” for Mg–Al/Ni–Al oxides.« less

  12. Surface Energy and Work Function Control of AlOx/Al Surfaces by Fluorinated Benzylphosphonic Acids.

    PubMed

    Abraham, Ffion; Ford, William E; Scholz, Frank; Nelles, Gabriele; Sandford, Graham; von Wrochem, Florian

    2016-05-11

    The performance of organic electronic devices can be significantly improved by modifying metal electrodes with organic monolayers, which alter the physical and chemical nature of the interface between conductor and semiconductor. In this paper we examine a series of 12 phosphonic acid compounds deposited on the native oxide layer of aluminum (AlOx/Al), an electrode material with widespread applications in organic electronics. This series includes dodecylphosphonic acid as a reference and 11 benzylphosphonic acids, seven of which are fluorinated, including five newly synthesized derivatives. The monolayers are experimentally characterized by contact angle goniometry and by X-ray photoemission spectroscopy (XPS), and work function data obtained by low-intensity XPS are correlated with molecular dipoles obtained from DFT calculations. We find that monolayers are formed with molecular areas ranging from 17.7 to 42.9 Å(2)/molecule, and, by the choice of appropriate terminal groups, the surface energy can be tuned from 23.5 mJ/m(2) to 70.5 mJ/m(2). Depending on the number and position of fluorine substituents on the aromatic rings, a variation in the work function of AlOx/Al substrates over a range of 0.91 eV is achieved, and a renormalization procedure based on molecular density yields a surprising agreement of work function changes with interface dipoles as expected from Helmholtz' equation. The ability to adjust energetics and adhesion at organic semiconductor/AlOx interfaces has immediate applications in devices such as OLEDs, OTFTs, organic solar cells, and printed organic circuits.

  13. Revealing heterogeneous nucleation of primary Si and eutectic Si by AlP in hypereutectic Al-Si alloys

    PubMed Central

    Li, Jiehua; Hage, Fredrik S.; Liu, Xiangfa; Ramasse, Quentin; Schumacher, Peter

    2016-01-01

    The heterogeneous nucleation of primary Si and eutectic Si can be attributed to the presence of AlP. Although P, in the form of AlP particles, is usually observed in the centre of primary Si, there is still a lack of detailed investigations on the distribution of P within primary Si and eutectic Si in hypereutectic Al-Si alloys at the atomic scale. Here, we report an atomic-scale experimental investigation on the distribution of P in hypereutectic Al-Si alloys. P, in the form of AlP particles, was observed in the centre of primary Si. However, no significant amount of P was detected within primary Si, eutectic Si and the Al matrix. Instead, P was observed at the interface between the Al matrix and eutectic Si, strongly indicating that P, in the form of AlP particles (or AlP ‘patch’ dependent on the P concentration), may have nucleated on the surface of the Al matrix and thereby enhanced the heterogeneous nucleation of eutectic Si. The present investigation reveals some novel insights into heterogeneous nucleation of primary Si and eutectic Si by AlP in hypereutectic Al-Si alloys and can be used to further develop heterogeneous nucleation mechanisms based on adsorption. PMID:27120994

  14. 77 FR 40492 - Revocation of Class D Airspace; Andalusia, AL; and Amendment of Class E Airspace; Fort Rucker, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-10

    ...: Final rule. SUMMARY: This action removes Class D Airspace at Andalusia, AL, as the Air Traffic Control... Airport), Andalusia, AL, due to the closing of the air traffic control tower; amend Class E airspace at... Regional Airport at Bill Benton Field (formerly Andalusia-Opp Airport), Andalusia, AL, as the air traffic...

  15. Screening for cognition and behaviour changes in ALS.

    PubMed

    Abrahams, Sharon; Newton, Judith; Niven, Elaine; Foley, Jennifer; Bak, Thomas H

    2014-03-01

    This study presents the Edinburgh Cognitive and Behavioural ALS Screen (ECAS), developed for ALS patients with physical disability for use by health care professionals. The screen is designed to detect the specific profile of cognition and behaviour changes in ALS and to differentiate it from other disorders. Forty-eight ALS patients (none with evident dementia), 40 healthy controls and 20 carers were recruited. The ECAS, a 15-20-min screen, includes an ALS-Specific score (executive functions and social cognition; fluency; language); an ALS Non-specific score (memory; visuospatial functions); and a carer behaviour screen of five domains characteristic of frontotemporal dementia (FTD). Data from healthy controls produced abnormality cut-offs of 77/100 ALS-Specific score; 24/36 ALS Non-specific score; 105/136 ECAS Total. Twenty-nine percent of patients showed abnormal ALS-Specific scores, and 6% also showed abnormal ALS Non-specific scores. The most prevalent deficit occurred in language functions (35%) followed by executive functions and fluency (23% each). Forty percent of carers reported behaviour change in at least one domain, while 15% met criteria for possible FTD. In conclusion, the ECAS is an effective within-clinic assessment for ALS that determines the presence, severity and type of cognitive and/or behavioural changes, an essential first step to managing these symptoms.

  16. Syntactic comprehension deficits across the FTD-ALS continuum.

    PubMed

    Kamminga, Jody; Leslie, Felicity V C; Hsieh, Sharpley; Caga, Jashelle; Mioshi, Eneida; Hornberger, Michael; Ballard, Kirrie J; Kiernan, Matthew C; Hodges, John R; Burrell, James R

    2016-05-01

    To establish the frequency, severity, relationship to bulbar symptoms, and neural correlates of syntactic comprehension deficits across the frontotemporal dementia-amyotrophic lateral sclerosis (FTD-ALS) disease spectrum. In total, 85 participants were included in the study; 20 amyotrophic lateral sclerosis (ALS), 15 FTD-ALS, 27 progressive nonfluent aphasia (PNFA), and 23 controls. Syntactic comprehension was evaluated in ALS, FTD-ALS, PNFA, and controls using the Test for Reception of Grammar. Voxel-based morphometry examined neuroanatomical correlates of performance. Syntactic comprehension deficits were detected in 25% of ALS (p = 0.011), 92.9% of FTD-ALS (p < 0.001), and 81.5% of PNFA (p < 0.001) patients. FTD-ALS was disproportionately impaired compared to PNFA. Impaired Test for Reception of Grammar performance was frequent in ALS with early bulbar involvement but did not correlate with bulbar impairment overall. Left peri-insular atrophy correlated with syntactic comprehension deficits. Syntactic comprehension deficits are frequent in FTD-ALS, more severe than in PNFA, and related to left peri-insular atrophy. A significant minority of ALS patients are impaired, but the relationship between bulbar symptoms and syntactic impairment is not understood. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Peritectoid formation of ordered Zr/sub 3/Al

    SciTech Connect

    Schulson, E.M.; Graham, D.B.

    1976-07-01

    The kinetics of the peritectoid transformation Zr + Zr/sub 2/Al ..-->.. Zr/sub 3/Al have been examined in Zr 7.6 to 9.0 wt% Al ingots using isothermal annealing and optical microscopy. The transformation is a nucleation and thermally activated growth process in which nucleation occurs heterogeneously at Zr/sub 2/Al/Zr interface and growth occurs by the diffusion controlled migration in opposite directions of the Zr/sub 3/Al/Zr and Zr/sub 3/Al/Zr/sub 2/Al interfaces. The nucleation rate is a maximum at approximately equal to 1160/sup 0/K (i.e., at approximately equal to 100/sup 0/K below the equilibrium peritectoid temperature). Isothermal transformation curves are presented and explainedmore » quantitatively in terms of the nucleation and parabolic growth kinetics.« less

  18. 26Al uptake and accumulation in the rat brain

    NASA Astrophysics Data System (ADS)

    Yumoto, S.; Nagai, H.; Imamura, M.; Matsuzaki, H.; Hayashi, K.; Masuda, A.; Kumazawa, H.; Ohashi, H.; Kobayashi, K.

    1997-03-01

    To investigate the cause of Alzheimer's disease (senile dementia), 26Al incorporation in the rat brain was studied by accelerator mass spectrometry (AMS). When 26Al was injected into healthy rats, a considerable amount of 26Al entered the brain (cerebrum) through the blood-brain barrier 5 days after a single injection, and the brain 26Al level remained almost constant from 5 to 270 days. On the other hand, the level of 26Al in the blood decreased remarkably 75 days after injection. Approximately 89% of the 26Al taken in by the brain cell nuclei bound to chromatin. This study supports the theory that Alzheimer's disease is caused by irreversible accumulation of aluminium (Al) in the brain, and brain cell nuclei.

  19. Photoluminescence of oxygen vacancies in nanostructured Al2O3

    NASA Astrophysics Data System (ADS)

    Kostyukov, Anton I.; Zhuzhgov, Aleksey V.; Kaichev, Vasily V.; Rastorguev, Alexander A.; Snytnikov, Vladimir N.; Snytnikov, Valeriy N.

    2018-01-01

    Oxygen vacancies represented by F and F2 centers were detected in faceted Al2O3 nanoparticles with the size less than 10 nm by a photoluminescence method. Al2O3 nanoparticles with such intrinsic defects were synthesized by evaporation of α-Al2O3 in flowing helium using a continuous wave CO2 laser. The XRD analysis showed that the crystal structure of Al2O3 nanoparticles is represented mostly by the low-temperature γ- and/or η-Al2O3 phases. The luminescence maxima of F and F2 centers in the Al2O3 nanoparticles were found to be 3.07 and 2.47 eV. These values are close to the luminescence maxima of F and F2 centers in bulk α-Al2O3.

  20. Therapeutic targeting of epigenetic components in amyotrophic lateral sclerosis (ALS).

    PubMed

    Lee, J; Ryu, H; Keum, G; Yoon, Y J; Kowall, N W; Ryu, H

    2014-01-01

    Amyotrophic lateral sclerosis (ALS) is an adult-onset motor neuron disease characterized by degeneration of motor neuron and glial activation followed by the progressive muscle loss and paralysis. Numerous distinct therapeutic interventions have been examined but currently ALS does not have a cure or an efficacious treatment for the disorder. Glutamate- induced excitotoxicity, inflammation, mitochondrial dysfunction, oxidative stress, protein aggregation, transcription deregulation, and epigenetic modifications are associated with the pathogenesis of ALS and known to be therapeutic targets in ALS. In this review, we discuss translational pharmacological studies targeting epigenetic components to ameliorate ALS. Understanding of the epigenetic mechanisms will provide novel insights that will further identify potential biological markers and therapeutic approaches for treating ALS. A combination of treatments that modulate epigenetic components and multiple targets may prove to be the most effective therapy for ALS.

  1. 1200 to 1400 K slow strain rate compressive behavior of small grain size NiAl/Ni2AlTi alloys and NiAl/Ni2AlTi-TiB2 composites

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Viswanadham, R. K.; Mannan, S. K.; Kumar, K. S.

    1989-01-01

    In order to impart ductility into NiAl-Ni2AlTi alloys, small grain size single (Ni-45Al-5Ti) and two (Ni-40Al-10Ti) phase intermetallics are fabricated by a process which yields fine microstructures in NiAl. The results of a study of elevated temperature compressive properties of two small grain size NiAl-Ni2AlTi alloys are then described. In addition, the behavior of the Ti-modified nickel aluminides with 20 vol pct TiB2 particles of approximately 1 micron in diameter is also investigated, since these compositions have the potential for being the matrix material in high temperature particulate-strengthened composites.

  2. 77 FR 61046 - The Amendment of the Designation of Al-Qa'ida in the Arabian Peninsula, aka Al-Qa'ida of Jihad...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-05

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE The Amendment of the Designation of Al-Qa'ida in the Arabian Peninsula, aka Al-Qa'ida of Jihad Organization in the Arabian Peninsula, aka Tanzim Qa'idat al-Jihad fi Jazirat al-Arab, aka Al- Qa'ida in Yemen, aka Al...

  3. 77 FR 73732 - In the Matter of the Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-11

    ... The al-Zarqawi Network, aka al-Tawhid, aka Tanzim Qa`idat al-Jihad fi Bilad al-Rafidayn, aka The... the Two Rivers, aka Tanzeem qa'idat al Jihad/Bildad al Raafidaini, as a Specially Designated Global... in Iraq as a Specially Designated Global Terrorist entity, pursuant to Executive Order 13224, to...

  4. Measured Activities of Al and Ni in gamma-(Ni) and gamma'-(Ni)3Al in the Ni-Al-Pt System

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2007-01-01

    Adding Pt to Ni-Al coatings is critical to achieving the required oxidation protection of Ni-based superalloys, but the nature of the Pt effect remains unresolved. This research provides a fundamental part of the answer by measuring the influence of Pt on the activities of Al and Ni in gamma-(Ni), gamma prime-(Ni)3Al and liquid in the Ni-Al-Pt system. Measurements have been made at 25 compositions in the Ni-rich corner over the temperature range, T = 1400-1750 K, by the vapor pressure technique with a multiple effusion-cell mass spectrometer (multi-cell KEMS). These measurements clearly show adding Pt (for X(sub Pt) less than 0.25) decreases a(Al) while increasing a(Ni). This solution behavior supports the idea that Pt increases Al transport to an alloy / Al2O3 interface and also limits the interaction between the coating and substrate alloys in the gamma-(Ni) + gamma prime-(Ni)3Al region. This presentation will review the progress of this study.

  5. Transcriptome Analysis of Al-Induced Genes in Buckwheat (Fagopyrum esculentum Moench) Root Apex: New Insight into Al Toxicity and Resistance Mechanisms in an Al Accumulating Species

    PubMed Central

    Xu, Jia Meng; Fan, Wei; Jin, Jian Feng; Lou, He Qiang; Chen, Wei Wei; Yang, Jian Li; Zheng, Shao Jian

    2017-01-01

    Relying on Al-activated root oxalate secretion, and internal detoxification and accumulation of Al, buckwheat is highly Al resistant. However, the molecular mechanisms responsible for these processes are still poorly understood. It is well-known that root apex is the critical region of Al toxicity that rapidly impairs a series of events, thus, resulting in inhibition of root elongation. Here, we carried out transcriptome analysis of the buckwheat root apex (0–1 cm) with regards to early response (first 6 h) to Al stress (20 μM), which is crucial for identification of both genes and processes involved in Al toxicity and tolerance mechanisms. We obtained 34,469 unigenes with 26,664 unigenes annotated in the NCBI database, and identified 589 up-regulated and 255 down-regulated differentially expressed genes (DEGs) under Al stress. Functional category analysis revealed that biological processes differ between up- and down-regulated genes, although ‘metabolic processes’ were the most affected category in both up- and down-regulated DEGs. Based on the data, it is proposed that Al stress affects a variety of biological processes that collectively contributes to the inhibition of root elongation. We identified 30 transporter genes and 27 transcription factor (TF) genes induced by Al. Gene homology analysis highlighted candidate genes encoding transporters associated with Al uptake, transport, detoxification, and accumulation. We also found that TFs play critical role in transcriptional regulation of Al resistance genes in buckwheat. In addition, gene duplication events are very common in the buckwheat genome, suggesting a possible role for gene duplication in the species’ high Al resistance. Taken together, the transcriptomic analysis of buckwheat root apex shed light on the processes that contribute to the inhibition of root elongation. Furthermore, the comprehensive analysis of both transporter genes and TF genes not only deep our understanding on the responses

  6. Microstructure and Properties of Fe3Al-Fe3AlC x Composite Prepared by Reactive Liquid Processing

    NASA Astrophysics Data System (ADS)

    Verona, Maria Nalu; Setti, Dalmarino; Paredes, Ramón Sigifredo Cortés

    2017-12-01

    A Fe3Al-Fe3AlC x composite was prepared using reactive liquid processing (RLP) through controlled mixture of carbon steel and aluminum in the liquid state. The microstructure and phases of the composite were assessed using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, optical microscopy, and differential scanning calorimetry. In addition, the density, hardness, microhardness, and elastic modulus were evaluated. The Fe3Al-Fe3AlC x composite consisted of 65 vol pct Fe3Al and 35 vol pct Fe3AlC x (κ). The κ phase contained 10.62 at. pct C, resulting in the stoichiometry Fe3AlC0.475. The elastic modulus of the Fe3Al-Fe3AlC0.475 composite followed the rule of mixtures. The RLP technique was shown to be capable of producing Fe3Al-Fe3AlC0.475 with a microstructure and properties similar to those achieved using other processing techniques reported in the literature.

  7. Al-Cu-Li and Al-Mg-Li alloys: Phase composition, texture, and anisotropy of mechanical properties (Review)

    NASA Astrophysics Data System (ADS)

    Betsofen, S. Ya.; Antipov, V. V.; Knyazev, M. I.

    2016-04-01

    The results of studying the phase transformations, the texture formation, and the anisotropy of the mechanical properties in Al-Cu-Li and Al-Mg-Li alloys are generalized. A technique and equations are developed to calculate the amounts of the S1 (Al2MgLi), T1 (Al2CuLi), and δ' (Al3Li) phases. The fraction of the δ' phase in Al-Cu-Li alloys is shown to be significantly higher than in Al-Mg-Li alloys. Therefore, the role of the T1 phase in the hardening of Al-Cu-Li alloys is thought to be overestimated, especially in alloys with more than 1.5% Li. A new model is proposed to describe the hardening of Al-Cu-Li alloys upon aging, and the results obtained with this model agree well with the experimental data. A texture, which is analogous to that in aluminum alloys, is shown to form in sheets semiproducts made of Al-Cu-Li and Al-Mg-Li alloys. The more pronounced anisotropy of the properties of lithium-containing aluminum alloys is caused by a significant fraction of the ordered coherent δ' phase, the deformation mechanism in which differs radically from that in the solid solution.

  8. Systematics of variations in excess Al and Al/Ti in sediments from the central equatorial Pacific

    NASA Astrophysics Data System (ADS)

    Timothy, David A.; Calvert, Stephen E.

    1998-04-01

    The proposal that the accumulation rate (AR) of scavenged Al in central equatorial Pacific sediments is controlled by bulk particle flux and therefore can be used as a paleoproduction proxy is tested by examining the relationship between Al and Ti using data on core WEC8803B-GC51 published by Murray et al. [1993]. The downcore profile of the excess Al AR follows the bulk AR, consistent with the Al-scavenging hypothesis and is due to a relatively constant abundance of excess Al down core. However, there have been large changes in the aluminosilicate AR to this region, suggesting that changes in the Al/Ti value do not solely trace variability in the delivery rate of scavenged Al. Assuming that the excess Al in this core is not the result of an analytical artifact, we present an alternative to the Al-scavenging hypothesis that involves authigenic clay mineral formation, or some other process, causing the occurrence of excess Al at a relatively constant abundance of the sediment. This process may well be independent of bulk particle flux or paleoproduction.

  9. Comparison of ALS functionality and plant growth in ALS-inhibitor susceptible and resistant Myosoton aquaticum L.

    PubMed

    Liu, Weitang; Bai, Shuang; Jia, Sisi; Guo, Wenlei; Zhang, Lele; Li, Wei; Wang, Jinxin

    2017-10-01

    Herbicide target-site resistance mutations may cause pleiotropic effects on plant ecology and physiology. The effect of several known (Pro197Ser, Pro197Leu Pro197Ala, and Pro197Glu) target-site resistance mutations of the ALS gene on both ALS functionality and plant vegetative growth of weed Myosoton aquaticum L. (water chickweed) have been investigated here. The enzyme kinetics of ALS from four purified water chickweed populations that each homozygous for the specific target-site resistance-endowing mutations were characterized and the effect of these mutations on plant growth was assessed via relative growth rate (RGR) analysis. Plants homozygous for Pro197Ser and Pro197Leu exhibited higher extractable ALS activity than susceptible (S) plants, while all ALS mutations with no negative change in ALS kinetics. The Pro197Leu mutation increased ALS sensitivity to isoleucine and valine, and Pro197Glu mutation slightly increased ALS sensitivity to isoleucine. RGR results indicated that none of these ALS resistance mutations impose negative pleiotropic effects on relative growth rate. However, resistant (R) seeds had a lowed germination rate than S seeds. This study provides baseline information on ALS functionality and plant growth characteristics associated with ALS inhibitor resistance-endowing mutations in water chickweed. Copyright © 2017. Published by Elsevier Inc.

  10. Microstructural development in Al/MgAl2O4in situmetal matrix composite using value-added silica sources.

    PubMed

    Madathil Sreekumar, Vadakke; Marimuthu Pillai, Raman; Chandrasekhara Pai, Bellampettu; Chakraborty, Madhusudhan

    2008-01-01

    Al/MgAl 2 O 4 in situ metal matrix composites have been synthesized using value-added silica sources (microsilica and rice husk ash) containing ∼97% SiO 2 in Al-5 wt.% Mg alloy. The thermodynamics and kinetics of MgAl 2 O 4 formation are discussed in detail. The MgO and MgAl 2 O 4 phases were found to dominate in microsilica (MS) and rice husk ash (RHA) value-added composites, respectively, during the initial stage of holding the composites at 750 °C. A transition phase between MgO and MgAl 2 O 4 was detected by the scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS) analysis of the particles extracted from the composite using 25% NaOH solution. This confirms that MgO is gradually transformed to MgAl 2 O 4 by the reaction 3SiO 2(s) +2MgO (s) +4Al (l) →2MgAl 2 O 4(s) +3Si (l) . The stoichiometry of MgAl 2 O 4 , n , computed by a new methodology is between 0.79 and 1.18. The reaction between the silica sources and the molten metal stopped after 55% of the silica source was consumed. A gradual increase in mean MgAl 2 O 4 crystallite size, D , from 24 to 36 nm was observed in the samples held for 10 h.

  11. Effect of Al content on impact resistance behavior of Al-Ti-B4C composite fabricated under air atmosphere.

    PubMed

    Zhao, Qian; Liang, Yunhong; Zhang, Zhihui; Li, Xiujuan; Ren, Luquan

    2016-12-01

    Reaction behavior, mechanical property and impact resistance of TiC-TiB 2 /Al composite reacted from Al-Ti-B 4 C system with various Al content via combination method of combustion synthesis and hot pressed sintering under air was investigated. Al content was the key point to the variation of mechanical property and impact resistance. Increasing Al content could increase the density, strength and toughness of the composite. Due to exorbitant ceramic content, 10wt.% and 20wt.% Al-Ti-B 4 C composites exhibited poor molding ability and machinability. Flexural strength, fracture toughness, compressive strength and impact toughness of 30-50wt.% Al-Ti-B 4 C composite were higher than those of Al matrix. The intergranular fracture dispersed and defused impact load and restricted crack extension, enhancing the impact resistance of the composite. The composite with 50wt.% Al content owned highest mechanical properties and impact resistance. The results were useful for the application of TiC-TiB 2 /Al composite in impact resistance field of ceramic reinforced Al matrix composite. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Azide SHS of aluminium nitride nanopowder and its application for obtaining Al-Cu-AlN cast nanocomposite

    NASA Astrophysics Data System (ADS)

    Titova, Y. V.; Sholomova, A. V.; Kuzina, A. A.; Maidan, D. A.; Amosov, A. P.

    2016-11-01

    Method of azide self-propagating high-temperature synthesis (SHS-Az), using sodium azide (NaN3) as a nitriding reagent, was used for obtaining the nanopowder of aluminum nitride (AlN) from precursor that was sodium hexafluoroaluminate (Na3AlF6). The product of burning the mixture of Na3AlF6 + 3NaN3 after water rinsing consisted of micro - and nanoparticles of AlN (65%) and the residue of salt Na3AlF6 (35%). This product of SHS-Az was mixed with copper powder and pressed into a briquette of nanopowdery master alloy Cu- 4%(65%AlN+35%Na3AlF6), which was successfully introduced into aluminium melt at a temperature of 850°C. The salt Na3AlF6 in the product of combustion played a role of flux during introducing into the aluminum melt and was not included in the final composition of the composite alloy. The microstructure of the obtained cast composite aluminum alloy with the calculated composition of Al-1.2%Cu-0.035%AlN showed that the reinforcing particles of AlN of different sizes, including nanoparticles, were distributed mainly along the grain boundaries of the aluminum alloy.

  13. Positron lifetime studies of decomposition in 2024 (Al-Cu-Mg) and 7010 (Al-Zn-Cu-Mg) alloys

    SciTech Connect

    Dlubek, G. |; Lademann, P.; Krause, H.; Krause, S.; Unger, R.

    1998-09-04

    In the current paper, the decomposition behavior of the engineering alloys 2024 (Al-Cu-Mg) and 7010 (Al-Zn-Cu-Mg) is studied using positron lifetime measurements. Positrons probe open volume defects such as vacancies and dislocations. However, they may also be used to investigate coherent zones and incoherent precipitates. In order to understand the rather complicated precipitation sequences and the response of positrons to different type of precipitates occurring in 2024 and 7010 alloys, binary and ternary laboratory alloys were also investigated under the same experimental conditions as the engineering alloys. The interpretations of the results are based on experiences of the group from extensive positron studies of laboratory alloys such as Al-Zn, Al-Zn-Mg, Al-Cu, and further Al alloys (see also the review (4)). Their collected results are shown as lifetimes and curve-shape parameters S of the electron-positron momentum distribution curves characteristic for different precipitates in Al alloys.

  14. Bipolar resistive switching and conduction mechanism of an Al/ZnO/Al-based memristor

    NASA Astrophysics Data System (ADS)

    Gul, Fatih; Efeoglu, Hasan

    2017-01-01

    In this study, a direct-current reactive sputtered Al/ZnO/Al-based memristor device was fabricated and its resistive switching (RS) characteristics investigated. The optical and structural properties were confirmed by using UV-vis spectrophotometry and x-ray diffraction, respectively. The memristive and resistive switching characteristics were determined using time dependent current-voltage (I-V-t) measurements. The typical pinched hysteresis I-V loops of a memristor were observed. In addition, the device showed forming-free, uniform and bipolar RS behavior. The low electric field region exhibited ohmic conduction, while the Schottky emission (SE) was found to be the dominant conduction mechanism in the high electric field region. A weak Poole-Frenkel (PF) emission also appeared. In conclusion, it was suggested that the SE and PF mechanisms were related to the oxygen vacancies in the ZnO.

  15. Removing Al and regenerating caustic soda from the spent washing liquor of Al etching

    NASA Astrophysics Data System (ADS)

    Barakat, M. A.; El-Sheikh, S. M.; Farghly, F. E.

    2005-08-01

    Spent liquor from washing of aluminum section materials after etching with caustic soda (NaOH) has been treated. Aluminum was removed from the liquor and caustic soda was regenerated by adding precipitating agents to hydrolyze sodium aluminate (Na2AlO2), separating the aluminumprecipitate, and concentrating free NaOH in the resulting solution for reuse in the etching process. Four systems were investigated: hydrated lime [Ca(OH)2], hydrogen peroxide (H2O2), H2O2/Ca(OH)2 mixture, and dry lime (CaO). Results revealed that CaO was more efficient in the removal of aluminum from the spent liquor with a higher hydrolyzing rate of Na2AlO2 than Ca(OH)2, H2O2, or their mixture.

  16. Defect Band Characteristics in Mg-Al and Al-Si High-Pressure Die Castings

    NASA Astrophysics Data System (ADS)

    Gourlay, C. M.; Laukli, H. I.; Dahle, A. K.

    2007-08-01

    Bands of positive macrosegregation and porosity commonly follow the surface contour of components produced by high-pressure die casting (HPDC). In this article, Al alloy AlSi7Mg and Mg alloys AZ91 and AM60 were cast into tensile test bars using cold-chamber (cc) HPDC. Microstructural characterization revealed that externally solidified crystals (ESCs) are not necessary for defect band formation, and that defect bands can form both near to and relatively far from any surface layer of different microstructure. The defect bands were 140 to 240 μm thick. In addition to defect-band-related macrosegregation, the castings also contained inverse segregation and surface segregation. Defect bands are shown to have the characteristics of the dilatant shear bands reported in past rheology studies, indicating that defect bands form due to strain localization in partially solid material during the HPDC process.

  17. ALS Regional Variants (Brachial Amyotrophic Diplpegia, Leg Amyotrophic Diplegia, and Isolated Bulbar ALS)

    PubMed Central

    Jawdat, Omar; Statland, Jeffrey M.; Barohn, Richard J.; Katz, Jonathan; Dimachkie, Mazen M.

    2015-01-01

    Synopsis Amyotrophic lateral sclerosis is a rapidly progressive, invariably fatal disease, comprised of mixed upper and lower motor neuron involvement in different spinal cord regions. Characteristic initial presentations have implications for prognosis. Bulbar onset patients progress more rapidly than limb-onset patients, or patients with a pure lower motor neuron presentation. Other regional variants have been described where disease is restricted to one spinal region at presentation, including a flail arm or flail leg, and restricted respiratory or bulbar disease. More recent descriptions of regional variants suggest some ALS patients have disease isolated to a single spinal region for many years, including: brachial amyotrophic diplegia; leg amyotrophic diplegia; and isolated bulbar palsy. More clearly defining regional variants will have implications for prognosis, but also for understanding the pathophysiology of ALS, for identifying genetic factors related to slower disease progression, and for future clinical trial planning. PMID:26515621

  18. Blistering mechanisms of atomic-layer-deposited AlN and Al2O3 films

    NASA Astrophysics Data System (ADS)

    Broas, Mikael; Jiang, Hua; Graff, Andreas; Sajavaara, Timo; Vuorinen, Vesa; Paulasto-Kröckel, Mervi

    2017-10-01

    Blistering of protective, structural, and functional coatings is a reliability risk pestering films ranging from elemental to ceramic ones. The driving force behind blistering comes from either excess hydrogen at the film-substrate interface or stress-driven buckling. Contrary to the stress-driven mechanism, the hydrogen-initiated one is poorly understood. Recently, it was shown that in the bulk Al-Al2O3 system, the blistering is preceded by the formation of nano-sized cavities on the substrate. The stress- and hydrogen-driven mechanisms in atomic-layer-deposited (ALD) films are explored here. We clarify issues in the hydrogen-related mechanism via high-resolution microscopy and show that at least two distinct mechanisms can cause blistering in ALD films.

  19. Wear Analysis of CU-AL Coating on TI-6AL-4V Under Fretting

    DTIC Science & Technology

    2006-06-05

    the metallic coating is soft (has a low yield stress), movement between the two surfaces may be taken up in the coating. The coating must be able to...withstand very severe fatigue and wear and must adhere strongly to the substrate [19]. Cu-Al coating is one type of soft metallic coating that has...relative displacement between two materials (one hard and one soft ) takes place, it is possible for abrasive wear to occur and for the harder surface

  20. Synthesis and properties studies of nanocrystalline Al-Al[sub 3]Zr

    SciTech Connect

    Rittner, M.N.; Weertman, J.R.; Eastman, J.A.

    1994-10-01

    In this preliminary report, the feasibility of using the inert-gas condensation (IGC) technique with electron-beam evaporation to produce nanocrystalline (nc) Al-Zr samples with desirable microstructures and properties is described. Six nc samples were synthesized and consolidated at room temperature. The microstructural characteristics of the specimens were examined using various microscopy techniques, x-ray diffraction and Rutherford backscattering. Preliminary properties data were obtained from hot stage microscopy and Vickers microhardness measurements.

  1. Response to Lynn, et al.'s "Evaluation of Woodard's theory of perceptually oriented hypnosis".

    PubMed

    Woodard, Fredrick J

    2004-04-01

    In this article some misunderstandings of Perceptually Oriented Hypnosis presented in the recent evaluation by Lynn, et al. are pointed out. Perceptually Oriented Hypnosis emphasizes individual differences naturally occurring in the experience of everyday life or being-in-the-world and differentiation as major themes to understanding hypnosis. Woodard advocates that qualitative research enhances our understanding of hypnotic experiencing and allows us to examine hypnotic phenomena that elude the laboratory and control settings.

  2. Synthesis of new metal-matrix Al-Al2O3-graphene composite materials

    NASA Astrophysics Data System (ADS)

    Elshina, L. A.; Muradymov, R. V.; Kvashnichev, A. G.; Vichuzhanin, D. I.; Molchanova, N. G.; Pankratov, A. A.

    2017-08-01

    The mechanism of formation of ceramic microparticles (alumina) and graphene in a molten aluminum matrix is studied as a function of the morphology and type of precursor particles, the temperature, and the gas atmosphere. The influence of the composition of an aluminum composite material (as a function of the concentration and size of reinforcing particles) on its mechanical and corrosion properties, melting temperature, and thermal conductivity is investigated. Hybrid metallic Al-Al2O3-graphene composite materials with up to 10 wt % alumina microparticles and 0.2 wt % graphene films, which are uniformly distributed over the metal volume and are fully wetted with aluminum, are synthesized during the chemical interaction of a salt solution containing yttria and boron carbide with molten aluminum in air. Simultaneous introduction of alumina and graphene into an aluminum matrix makes it possible to produce hybrid metallic composite materials having a unique combination of the following properties: their thermal conductivity is higher than that of aluminum, their hardness and strength are increased by two times, their relative elongation during tension is increased threefold, and their corrosion resistance is higher than that of initial aluminum by a factor of 2.5-4. We are the first to synthesize an in situ hybrid Al-Al2O3-graphene composite material having a unique combination of some characteristics. This material can be recommended as a promising material for a wide circle of electrical applications, including ultrathin wires, and as a structural material for the aerospace industry, the car industry, and the shipbuilding industry.

  3. Al Qaeda in the Indian Subcontinent (AQIS): An Al Qaeda Affiliate Case Study

    DTIC Science & Technology

    2017-10-01

    W. Nicholson, Commander, Resolute Support and U.S. Forces-Afghanistan,” CTC Sentinel, February 22, 2017. 59 Thomas Joscelyn, “Al-Qaeda’s Kandahar...Support and U.S. Forces-Afghanistan,” CTC Sentinel, February 22, 2017. closely with American counterparts. Their collaboration is said to have led to the...the CT Foxhole: General John W. Nicholson, Commander, Resolute Support and U.S. Forces-Afghanistan.” CTC Sentinel 10, no. 2 (February 2017

  4. Combustion Synthesis Reaction Behavior of Cold-Rolled Ni/Al and Ti/Al Multilayers

    DTIC Science & Technology

    2011-04-01

    6   Figure 4 . Combustion synthesis process of the cold-rolled Ni/Al multilayer foils: (a) reaction front of the displacement of the reaction...Reactive Nanostructured Foil Used as a Heat Source for Joining Titanium . J. Appl. Phys. 2004, 96 ( 4 ), 2336–2342. 16. Wang, J.; Besnoin, E...2011 2. REPORT TYPE Final 3. DATES COVERED (From - To) January 2006–January 2008 4 . TITLE AND SUBTITLE Combustion Synthesis Reaction Behavior of

  5. 3DGRAPE/AL User's Manual

    NASA Technical Reports Server (NTRS)

    Sorenson, Reese L.; Alter, Stephen J.

    1995-01-01

    This document is a users' manual for a new three-dimensional structured multiple-block volume g generator called 3DGRAPE/AL. It is a significantly improved version of the previously-released a widely-distributed programs 3DGRAPE and 3DMAGGS. It generates volume grids by iteratively solving the Poisson Equations in three-dimensions. The right-hand-side terms are designed so that user-specific; grid cell heights and user-specified grid cell skewness near boundary surfaces result automatically, with little user intervention. The code is written in Fortran-77, and can be installed with or without a simple graphical user interface which allows the user to watch as the grid is generated. An introduction describing the improvements over the antecedent 3DGRAPE code is presented first. Then follows a chapter on the basic grid generator program itself, and comments on installing it. The input is then described in detail. After that is a description of the Graphical User Interface. Five example cases are shown next, with plots of the results. Following that is a chapter on two input filters which allow use of input data generated elsewhere. Last is a treatment of the theory embodied in the code.

  6. ALS liquid hydrogen turbopump: Advanced Development Program

    NASA Technical Reports Server (NTRS)

    Shimp, Nancy R.; Claffy, George J.

    1989-01-01

    The point of departure (POD) turbopump concept was reviewed and finalized. The basis for the POD was the configuration presented in the Aerojet proposal. After reviewing this proposal concept, several modifications were made. These modifications include the following: (1) the dual pump discharge arrangement was changed to a single discharge; (2) commonality of the turbine inlet manifold with the advanced launch system (ALS) liquid oxygen (LOX) TPA was dropped for this program; (3) the turbine housing flange arrangement was improved by relocating it away from the first stage nozzles; (4) a ten percent margin (five percent diameter increase) was built into the impeller design to ensure meeting the required discharge pressure without the need for increasing speed; (5) a ten percent turbine power margin was imposed which is to be obtained by increasing turbine inlet pressure if required; and (6) the backup concept, as an alternative to the use of cast impellers, now incorporates forged/machined shrouded impellers, rather than the unshrouded type originally planned.

  7. Whisker Formation in Porosity in Al Alloys

    NASA Astrophysics Data System (ADS)

    Griffiths, William David; Elsayed, Ahmed; El-Sayed, Mahmoud Ahmed

    2016-12-01

    An examination of the fracture surfaces of tensile test bars from Al alloy castings held in the liquid state for up to 20 minutes revealed porosity which in some cases contained whisker-like features. Energy-dispersive X-ray analysis in a SEM suggested that these might be oxide whiskers forming in an oxide-related pore or double oxide film defect. Such entrainment defects (also known as bifilms) may entrap a small amount of the local atmosphere when they form and become incorporated into the liquid metal. This atmosphere may be predominantly air, which then subsequently reacts with the surrounding melt, firstly by reaction with oxygen and secondly by reaction with nitrogen. A CFD model of the heat distribution associated with the reactions between the interior atmosphere of a double oxide film defect and the surrounding liquid alloy suggested that highly localized increases in temperature, up to about 2000 K to 5000 K (1727 °C to 4727 °C), could occur, over a scale of a few hundred micrometers. Such localized increases in temperature might lead to the evaporation or disassociation of oxide within the pore, followed by condensation, to form the whisker structures observed. Hydrogen might also be expected to diffuse into the bifilm and may play a role in the chemical reactions associated with the development of the bifilm.

  8. Shock induced reaction of Ni/Al nanopowder mixture.

    PubMed

    Meng, C M; Wei, J J; Chen, Q Y

    2012-11-01

    Nanopowder Ni/Al mixture (mixed in Al:Ni = 2:1 stoichiometry) was shock compressed by employing single and two-stage light gas gun. The particle size of Al and Ni are 100-200 nm and 50-70 nm respectively, morphologies of Al and Ni are sphere like either. Recovered product was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. According to the XRD spectrum, the mixed powder undergo complete reaction under shock compression, reaction product consist of Ni2Al3, NiAl and corundum structure Al2O3 compound. Grain size of Ni-Al compound is less than 100 nm. With the shock pressure increasing, the ratio of Ni2Al3 decreased obviously. The corundum crystal size is 400-500 nm according to the SEM observation. The results of shock recovery experiments and analysis show that the threshold pressure for reaction of nano size powder Ni/Al mixture is much less than that of micro size powder.

  9. MCrAlY bond coat with enhanced yttrium

    SciTech Connect

    Jablonski, Paul D.; Hawk, Jeffrey A.

    2016-08-30

    One or more embodiments relates to a method of producing an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y--Al.sub.2O.sub.3 layer. The MCrAlY layer is comprised of a .gamma.-M solid solution, a .beta.-MAl intermetallic phase, and Y-type intermetallics. The Y--Al.sub.2O.sub.3 layer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the Al.sub.2O.sub.3 lattice. The method comprises depositing an MCrAlY material on a substrate, applying an Y.sub.2O.sub.3 paste, and heating the substrate in a non-oxidizing atmosphere at a temperature between 400-1300.degree. C. for a time sufficient to generate the Y--Al.sub.2O.sub.3 layer. Both the MCrAlY layer and themore » Y--Al.sub.2O.sub.3 layer have a substantial absence of Y.sub.2O.sub.3, YAG, and YAP phases.« less

  10. Utility of repetitive nerve stimulation test for ALS diagnosis.

    PubMed

    Hatanaka, Yuki; Higashihara, Mana; Chiba, Takashi; Miyaji, Yosuke; Kawamura, Yasuomi; Sonoo, Masahiro

    2017-05-01

    Decremental responses in the repetitive nerve stimulation (RNS) test in amyotrophic lateral sclerosis (ALS) patients have been reported, although their possible diagnostic role has received little investigation. We investigated their diagnostic role in differentiation between ALS and cervical spondylotic amyotrophy (CSA), an important ALS mimic especially in Japan. Patients were prospectively enrolled and the diagnosis was confirmed by follow-up. RNS was performed on the abductor pollicis brevis (APB), upper trapezius (trapezius) and deltoid muscles. Enrolled subjects consisted of 53 ALS and 37 CSA patients. Abnormal decremental responses (>5%) were observed in 32%, 51% and 75% of ALS patients and 3%, 0% and 20% of CSA patients for the APB, trapezius and deltoid muscles, respectively. The sensitivity for 23 ALS patients with upper-limb onset was 78% for the trapezius and 100% for the deltoid muscles. An abnormal decremental response in the trapezius muscle was 100% specific to ALS in comparison with CSA: abnormal decrement in this muscle would strongly suggest ALS. No decrement in the deltoid muscle might exclude ALS in patients having symptoms with upper-limb onset. RNS is useful in differentiation between ALS and CSA. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  11. MCrAlY bond coat with enhanced yttrium

    DOEpatents

    Jablonski, Paul D.; Hawk, Jeffrey A.

    2016-08-30

    One or more embodiments relates to a method of producing an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y--Al.sub.2O.sub.3 layer. The MCrAlY layer is comprised of a .gamma.-M solid solution, a .beta.-MAl intermetallic phase, and Y-type intermetallics. The Y--Al.sub.2O.sub.3 layer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the Al.sub.2O.sub.3 lattice. The method comprises depositing an MCrAlY material on a substrate, applying an Y.sub.2O.sub.3 paste, and heating the substrate in a non-oxidizing atmosphere at a temperature between 400-1300.degree. C. for a time sufficient to generate the Y--Al.sub.2O.sub.3 layer. Both the MCrAlY layer and the Y--Al.sub.2O.sub.3 layer have a substantial absence of Y.sub.2O.sub.3, YAG, and YAP phases.

  12. Sporadic ALS Astrocytes Induce Neuronal Degeneration In Vivo.

    PubMed

    Qian, Kun; Huang, Hailong; Peterson, Andrew; Hu, Baoyang; Maragakis, Nicholas J; Ming, Guo-Li; Chen, Hong; Zhang, Su-Chun

    2017-04-11

    Astrocytes from familial amyotrophic lateral sclerosis (ALS) patients or transgenic mice are toxic specifically to motor neurons (MNs). It is not known if astrocytes from sporadic ALS (sALS) patients cause MN degeneration in vivo and whether the effect is specific to MNs. By transplanting spinal neural progenitors, derived from sALS and healthy induced pluripotent stem cells (iPSCs), into the cervical spinal cord of adult SCID mice for 9 months, we found that differentiated human astrocytes were present in large areas of the spinal cord, replaced endogenous astrocytes, and contacted neurons to a similar extent. Mice with sALS but not non-ALS cells showed reduced non-MNs numbers followed by MNs in the host spinal cord. The surviving MNs showed reduced inputs from inhibitory neurons and exhibited disorganized neurofilaments and aggregated ubiquitin. Correspondingly, mice with sALS but not non-ALS cells showed declined movement deficits. Thus, sALS iPSC-derived astrocytes cause ALS-like degeneration in both MNs and non-MNs. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  13. Impact of SiO2 on Al-Al thermocompression wafer bonding

    NASA Astrophysics Data System (ADS)

    Malik, Nishant; Schjølberg-Henriksen, Kari; Poppe, Erik U.; Taklo, Maaike M. V.; Finstad, Terje G.

    2015-03-01

    Al-Al thermocompression bonding suitable for wafer level sealing of MEMS devices has been investigated. This paper presents a comparison of thermocompression bonding of Al films deposited on Si with and without a thermal oxide (SiO2 film). Laminates of diameter 150 mm containing device sealing frames of width 200 µm were realized. The wafers were bonded by applying a bond force of 36 or 60 kN at bonding temperatures ranging from 300-550 °C for bonding times of 15, 30 or 60 min. The effects of these process variations on the quality of the bonded laminates have been studied. The bond quality was estimated by measurements of dicing yield, tensile strength, amount of cohesive fracture in Si and interfacial characterization. The mean bond strength of the tested structures ranged from 18-61 MPa. The laminates with an SiO2 film had higher dicing yield and bond strength than the laminates without SiO2 for a 400 °C bonding temperature. The bond strength increased with increasing bonding temperature and bond force. The laminates bonded for 30 and 60 min at 400 °C and 60 kN had similar bond strength and amount of cohesive fracture in the bulk silicon, while the laminates bonded for 15 min had significantly lower bond strength and amount of cohesive fracture in the bulk silicon.

  14. Unusual Oxidative Limitations for Al-MAX Phases

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2017-01-01

    Alumina-forming MAX phases are well-known for their excellent oxidation resistance, rivaling many metallic NiAl, NiCrAl, and FeCrAl counterparts and with upper temperature capability possible to approximately1400C. However a number of limitations have been emerging that need to be acknowledged to permit robust performance in demanding applications. Ti2AlC and Ti3AlC2 possess excellent scale adhesion, cyclic oxidation/moisture/volatility resistance, and TBC compatibility. However they are very sensitive to Al content and flux in order to maintain an exclusive Al2O3 scale without runaway oxidation of ubiquitous TiO2 transient scales. Accelerated oxidation has been shown to occur for Al-depleted, damaged, or roughened surfaces at temperatures less than 1200C. Conversely, Cr2AlC is less sensitive to transients, but exhibits volatile losses at 1200C or above if common Cr7C3 impurity phases are present. Poor scale adhesion is exhibited after oxidation at 1150C or above, where spallation occurs at the Cr7C3 (depletion zone) interface. Delayed spallation is significant and suggests a moisture-induced phenomenon similar to non-adherent metallic systems. Re-oxidation of this surface does not reproduce the initial pure Al2O3 behavior, but initiates a less-protective scale. Cr2AlC has also been shown to have good long term bonding with superalloys at 800C, but exhibits significant Beta-NiAl + Cr7C3 diffusion zones at 1100C and above. This may set limits on Cr2AlC as a high temperature TBC bond coat on Ni-based superalloys, while improving corrosion resistance in lower temperature applications.

  15. Hydrodeoxygenation of Guaiacol Over Pt/Al-SBA-15 Catalysts.

    PubMed

    Yu, Mi Jin; Park, Sung Hoon; Jeon, Jong-Ki; Ryu, Changkook; Sohn, Jung Min; Kim, Sang Chai; Park, Young-Kwon

    2015-01-01

    Upgrading of bio-oil through catalytic hydrodeoxygenation (HDO) reaction was investigated for guaiacol as a model compound. A batch reactor was used for the reaction condition of 40 bar and 250 degrees C. The target product was cyclohexane. Pt/Al-SBA-15 with the Si/Al ratios of 20, 40, and 80 and Pt/HZSM-5 were used as the catalyst. The SBA-15 catalysts were characterized by N2 adsorption-desorption, X-ray diffraction analysis, and temperature programmed desorption of ammonia. The order of cyclohexane yield was Pt/Al-SBA-15 (Si/Al = 20) > Pt/Al-SBA-15(40) > Pt/Al-SBA-15 (80), indicating that the quantity of acid sites plays an important role in the HDO reaction. On the other hand, Pt/HZSM-5 led to a very low cyclohexane yield, in spite of its abundant strong acid sites, due to its small pore size.

  16. Natural growth habit of bulk AlN crystals

    NASA Astrophysics Data System (ADS)

    Epelbaum, B. M.; Seitz, C.; Magerl, A.; Bickermann, M.; Winnacker, A.

    2004-05-01

    Growth conditions for self-nucleation and subsequent growth of bulk AlN crystals by sublimation are presented. With increasing growth temperature, the natural habit of AlN crystals changes from needle-like to prismatic and then turns to thick asymmetric platelet. The best-formed platelet crystals up to 14×7×2 mm 3 in size exhibit a number of atomically smooth surfaces. Growth morphology and crystal quality were found to be strongly influenced by the polar nature of AlN. Al-terminated faces produce mirror-like facets and transparent material of high crystalline quality, whereas development of N-terminated faces leads to opaque and defective sectors in grown crystals. It is suggested that the most successful seeded growth of AlN can be achieved along Al-terminated (0 0 0 1) , ( 1¯ 0 1 2) and non-polar ( 1¯ 0 1 0) faces.

  17. Al-doped cellulose ZnO hybrid nanocomposite

    NASA Astrophysics Data System (ADS)

    Mun, Seongcheol; Kim, Hyun-Chan; Ko, Hyun-U.; Yun, Youngmin; Kim, Jaehwan

    2017-04-01

    Cellulose based inorganic-organic hybrid nanocomposite was fabricated by growing ZnO nanorods on a transparent and flexible cellulose film. To improve its electrical and electromechanical properties, Al doping to ZnO was achieved during the ZnO nanorod growing by a hydrothermal synthesis with different ratio of Al and Zn derivative chemicals. As increasing the Al dopant ratio, the morphology changes from nanorod to the nanoplate. The Al dopant ratio also influences the electrical properties of the hybrid nanocomposite. 1.2% of Al/Zn molality ratio is found to be a critical value that changes the morphology and improves the electrical and electromechanical properties. Detail phenomenon and possible mechanism around the critical value of Al/Zn molarity ratio is discussed.

  18. Synthesis and Characterization of Si-Al, Si-Ti, Si-Zr, Al-Zr, Al-Ti, and Al-Ti-Zr Nanocomposites of Lamellar or Hexagonal Structure

    SciTech Connect

    de Farias, Robson F.; Airoldi, Claudio

    2001-05-01

    By using tetraethylortosilicate, titanium and zirconium tetrabutoxide, and aluminum sec-butoxide, as well as neutral 1,10 and 1,12 alkyldiamines or dodecyltrimethylammonium bromide as precursors, a series of six oxides, Si-Al, Si-Ti, Si-Zr, Al-Zr, Al-Ti, and Al-Ti-Zr, were obtained. These materials were characterized by infrared spectroscopy, thermogravimetry, X-ray diffraction patterns, and scanning electron microscopy. Si-Ti, Si-Zr, and Al-Ti matrices exhibit a lamellar structure, whereas the others have a hexagonal nature. With the exception of the Al-Ti matrix for which grains with spheric morphology are observed, all the other matrices exhibited grains with amorphous nature, as observed by SEM micrographs.

  19. Reactive codoping of GaAlInP compound semiconductors

    DOEpatents

    Hanna, Mark Cooper [Boulder, CO; Reedy, Robert [Golden, CO

    2008-02-12

    A GaAlInP compound semiconductor and a method of producing a GaAlInP compound semiconductor are provided. The apparatus and method comprises a GaAs crystal substrate in a metal organic vapor deposition reactor. Al, Ga, In vapors are prepared by thermally decomposing organometallic compounds. P vapors are prepared by thermally decomposing phospine gas, group II vapors are prepared by thermally decomposing an organometallic group IIA or IIB compound. Group VIB vapors are prepared by thermally decomposing a gaseous compound of group VIB. The Al, Ga, In, P, group II, and group VIB vapors grow a GaAlInP crystal doped with group IIA or IIB and group VIB elements on the substrate wherein the group IIA or IIB and a group VIB vapors produced a codoped GaAlInP compound semiconductor with a group IIA or IIB element serving as a p-type dopant having low group II atomic diffusion.

  20. Could Sirtuin Activities Modify ALS Onset and Progression?

    PubMed

    Tang, Bor Luen

    2017-10-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a complex etiology. Sirtuins have been implicated as disease-modifying factors in several neurological disorders, and in the past decade, attempts have been made to check if manipulating Sirtuin activities and levels could confer benefit in terms of neuroprotection and survival in ALS models. The efforts have largely focused on mutant SOD1, and while limited in scope, the results were largely positive. Here, the body of work linking Sirtuins with ALS is reviewed, with discussions on how Sirtuins and their activities may impact on the major etiological mechanisms of ALS. Moving forward, it is important that the potentially beneficial effect of Sirtuins in ALS disease onset and progression are assessed in ALS models with TDP-43, FUS, and C9orf72 mutations.

  1. Diffusion markers in Al/metal thin-film reactions

    NASA Astrophysics Data System (ADS)

    Colgan, E. G.; Mayer, J. W.

    1986-10-01

    A method was developed to measure the diffusing species in aluminide formation in cases where the reacted layer is laterally nonuniform. Rutherford backscattering spectrometry was used to determine the amount of each metal (atoms/cm 2) over the marker at different stages of the annealing sequence. This overlayer measurement gave equivalent results when compared with conventional energy width and marker displacement analysis in suicide formation. By using a tungsten marker diluted with Al, instead of a pure tungsten film, we minimized barrier problems. The marker was sandwiched between coevaporated layers of the compound being studied to reduce interface drag. We found for the growth of TiAl 3 and NiAl 3 that Al is the dominant moving species in agreement with previous results in thin-film (TiAl 3) and bulk (NiAl 3) measurements.

  2. Cost-Effective TiAl based Materials

    NASA Technical Reports Server (NTRS)

    Moxson, V. S.; Sun, Fusheng; Draper, Susan L.; Froes, F. H.; Duz, V.

    2003-01-01

    Because of their inherent low ductility, TiAl-based materials are difficult to fabricate, especially thin gage titanium gamma aluminide (TiAl) sheet and foil. In this paper, an innovative powder metallurgy approach for producing cost-effective thin gage TiAl sheets (with 356 mm long and 235 mm wide, and a thickness of 0.74, 1.09, 1.55, and 2.34 mm, respectively) is presented. The microstructures and tensile properties at room and elevated temperatures of the thin gage TiAl are studied. Results show that these TiAl sheets have a relatively homogenous chemistry, uniform microstructure, and acceptable mechanical properties. This work demonstrates a cost-effective method for producing both flat products (sheet/foil) and complex chunky parts of TiAl for various advanced applications including aerospace and automotive industries.

  3. Formation of Al3Ti/Mg composite by powder metallurgy of Mg-Al-Ti system.

    PubMed

    Yang, Zi R; Qi Wang, Shu; Cui, Xiang H; Zhao, Yu T; Gao, Ming J; Wei, Min X

    2008-07-01

    An in situ titanium trialuminide (Al 3 Ti)-particle-reinforced magnesium matrix composite has been successfully fabricated by the powder metallurgy of a Mg-Al-Ti system. The reaction processes and formation mechanism for synthesizing the composite were studied by differential scanning calorimetry (DSC), x-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Al 3 Ti particles are found to be synthesized in situ in the Mg alloy matrix. During the reaction sintering of the Mg-Al-Ti system, Al 3 Ti particles are formed through the reaction of liquid Al with as-dissolved Ti around the Ti particles. The formed intermetallic particles accumulate at the original sites of the Ti particles. As sintering time increases, the accumulated intermetallic particles disperse and reach a relatively homogeneous distribution in the matrix. It is found that the reaction process of the Mg-Al-Ti system is almost the same as that of the Al-Ti system. Mg also acts as a catalytic agent and a diluent in the reactions and shifts the reactions of Al and Ti to lower temperatures. An additional amount of Al is required for eliminating residual Ti and solid-solution strengthening of the Mg matrix.

  4. 93Nb- and 27Al-NMR/NQR studies of the praseodymium based PrNb2Al20

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2015-03-01

    We report a study of 93Nb- and 27Al-nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) in a praseodymium based compound PrNb2Al20. The observed NMR line at around 3 T and 30 K shows a superposition of typical powder patterns of one Nb signal and at least two Al signals. 93Nb-NMR line could be reproduced by using the previously reported NQR frequency νQ ≊ 1.8MHz and asymmetry parameter η ≊ 0 [Kubo T et al 2014 JPS Conf. Proc. 3 012031]. From 27Al-NMR/NQR, NQR parameters are obtained to be νQ,A ≊ 1.53 MHz, and ηA ≊ 0.20 for the site A, and νQ,B ≊ 2.28 MHz, and ηB ≊ 0.17 for the site B. By comparing this result with the previous 27Al-NMR study of PrT2Al20 (T = Ti, V) [Tokunaga Y et al 2013 Phys. Rev. B 88 085124], these two Al site are assigned to the two of three crystallographycally inequivalent Al sites.

  5. Elastocaloric effect in CuAlZn and CuAlMn shape memory alloys under compression.

    PubMed

    Qian, Suxin; Geng, Yunlong; Wang, Yi; Pillsbury, Thomas E; Hada, Yoshiharu; Yamaguchi, Yuki; Fujimoto, Kenjiro; Hwang, Yunho; Radermacher, Reinhard; Cui, Jun; Yuki, Yoji; Toyotake, Koutaro; Takeuchi, Ichiro

    2016-08-13

    This paper reports the elastocaloric effect of two Cu-based shape memory alloys: Cu68Al16Zn16 (CuAlZn) and Cu73Al15Mn12 (CuAlMn), under compression at ambient temperature. The compression tests were conducted at two different rates to approach isothermal and adiabatic conditions. Upon unloading at a strain rate of 0.1 s(-1) (adiabatic condition) from 4% strain, the highest adiabatic temperature changes (ΔTad) of 4.0 K for CuAlZn and 3.9 K for CuAlMn were obtained. The maximum stress and hysteresis at each strain were compared. The stress at the maximum recoverable strain of 4.0% for CuAlMn was 120 MPa, which is 70% smaller than that of CuAlZn. A smaller hysteresis for the CuAlMn alloy was also obtained, about 70% less compared with the CuAlZn alloy. The latent heat, determined by differential scanning calorimetry, was 4.3 J g(-1) for the CuAlZn alloy and 5.0 J g(-1) for the CuAlMn alloy. Potential coefficients of performance (COPmat) for these two alloys were calculated based on their physical properties of measured latent heat and hysteresis, and a COPmat of approximately 13.3 for CuAlMn was obtained.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'. © 2016 The Author(s).

  6. Elastocaloric effect in CuAlZn and CuAlMn shape memory alloys under compression

    PubMed Central

    Qian, Suxin; Wang, Yi; Pillsbury, Thomas E.; Hada, Yoshiharu; Yamaguchi, Yuki; Fujimoto, Kenjiro; Hwang, Yunho; Radermacher, Reinhard; Cui, Jun; Yuki, Yoji; Toyotake, Koutaro; Takeuchi, Ichiro

    2016-01-01

    This paper reports the elastocaloric effect of two Cu-based shape memory alloys: Cu68Al16Zn16 (CuAlZn) and Cu73Al15Mn12 (CuAlMn), under compression at ambient temperature. The compression tests were conducted at two different rates to approach isothermal and adiabatic conditions. Upon unloading at a strain rate of 0.1 s−1 (adiabatic condition) from 4% strain, the highest adiabatic temperature changes (ΔTad) of 4.0 K for CuAlZn and 3.9 K for CuAlMn were obtained. The maximum stress and hysteresis at each strain were compared. The stress at the maximum recoverable strain of 4.0% for CuAlMn was 120 MPa, which is 70% smaller than that of CuAlZn. A smaller hysteresis for the CuAlMn alloy was also obtained, about 70% less compared with the CuAlZn alloy. The latent heat, determined by differential scanning calorimetry, was 4.3 J g−1 for the CuAlZn alloy and 5.0 J g−1 for the CuAlMn alloy. Potential coefficients of performance (COPmat) for these two alloys were calculated based on their physical properties of measured latent heat and hysteresis, and a COPmat of approximately 13.3 for CuAlMn was obtained. This article is part of the themed issue ‘Taking the temperature of phase transitions in cool materials’. PMID:27402936

  7. A randomized trial of mexiletine in ALS

    PubMed Central

    Macklin, Eric A.; Simmons, Zachary; Knox, Angela S.; Greenblatt, David J.; Atassi, Nazem; Graves, Michael; Parziale, Nicholas; Salameh, Johnny S.; Quinn, Colin; Brown, Robert H.; Distad, Jane B.; Trivedi, Jaya; Shefner, Jeremy M.; Barohn, Richard J.; Pestronk, Alan; Swenson, Andrea; Cudkowicz, Merit E.

    2016-01-01

    Objective: To determine the safety and tolerability of mexiletine in a phase II double-blind randomized controlled trial of sporadic amyotrophic lateral sclerosis (SALS). Methods: Sixty participants with SALS from 10 centers were randomized 1:1:1 to placebo, mexiletine 300 mg/d, or mexiletine 900 mg/d and followed for 12 weeks. The primary endpoints were safety and tolerability. Secondary endpoints were pharmacokinetic study from plasma and CSF, ALS Functional Rating Scale–Revised (ALSFRS-R) score, slow vital capacity (SVC), and muscle cramp frequency and severity. Results: The only serious adverse event among active arm participants was one episode of imbalance. Thirty-two percent of participants receiving 900 mg of mexiletine discontinued study drug vs 5% on placebo (p = 0.026). Pharmacokinetic study demonstrated a peak plasma concentration 2 hours postdose and strong correlation between plasma and CSF (p < 0.001). Rates of decline of ALSFRS-R and SVC did not differ from placebo. Analysis of all randomized patients demonstrated significant reductions of muscle cramp frequency (300 mg: rate = 31% of placebo, p = 0.047; 900 mg: 16% of placebo, p = 0.002) and cramp intensity (300 mg: mean = 45% of placebo, p = 0.08; 900 mg: 25% of placebo, p = 0.005). Conclusions: Mexiletine was safe at both doses and well-tolerated at 300 mg/d but adverse effects at 900 mg/d led to a high rate of discontinuation. Mexiletine treatment resulted in large dose-dependent reductions in muscle cramp frequency and severity. No effect on rate of progression was detected, but clinically important differences could not be excluded in this small and short-duration study. Classification of evidence: This study provides Class I evidence that mexiletine is safe when given daily to patients with amyotrophic lateral sclerosis at 300 and 900 mg and well-tolerated at the lower dose. PMID:26911633

  8. Suitability of Defector Operations Applied Against Al Qaeda

    DTIC Science & Technology

    2008-05-01

    Japanese service members was similar to that being displayed by Al Qaeda members. 2 be answered is: what would the required organizational and...operational structure to conduct a defector program against Al Qaeda cost? To answer this question the requirements for running a defector operation tailored...for Al Qaeda would have to be determined.6 A key aspect would be determining the expenditure in effort and money required from U.S. agencies and

  9. Thermally induced structural modification in the Al/Zr multilayers

    NASA Astrophysics Data System (ADS)

    Zhong, Qi; Zhang, Zhong; Ma, Shuang; Qi, Runze; Li, Jia; Wang, Zhanshan; Jonnard, Philippe; Le Guen, Karine; André, Jean-Michel

    2013-08-01

    The effect of increasing temperature on the structural stability and interactions of two kinds of Al/Zr (Al(1%wtSi)/Zr and Al(Pure)/Zr) multilayer mirrors are investigated. All Al/Zr multilayers annealed from 200 °C to 500 °C were deposited on Si wafers by using direct-current magnetron sputtering technology. A detailed and consistent picture of the thermally induced changes in the microstructure is obtained using an array of complementary measurements including grazing incidence X-ray reflectometry, atomic force microscopy, X-ray diffraction and high-resolution transmission electron microscopy. The first significant structural changes of two systems are observed at 250 °C, characterized by asymmetrical interlayers appearing at interface. At 290 °C, the interface consisting of amorphous Al-Zr alloy is transformed to amorphous Al-Zr alloy and cubic ZrAl3 in both systems. At 298 °C for Al(1%wtSi)/Zr and 295 °C for Al(Pure)/Zr multilayers, the interfacial phases of Al-Zr alloy transform into polycrystalline mixtures of hcp-ZrAl2 and cubic-ZrAl3, which smooth the interface boundary and lower the surface roughness in the multilayers. Up to 500 °C, the multilayer structure still exists in both systems, and the differences between the asymmetrical interlayers are much larger in the multilayers. Finally, we discuss the transformation from symmetrical to asymmetrical in the annealing process for other multilayer systems.

  10. The Current Palestinian Uprising: Al-Aqsa Intifadah

    DTIC Science & Technology

    2001-01-01

    Palestinian Uprising: Al-Aqsa Intifadah Updated January 5, 2001 Joshua Ruebner, Clyde Mark, Kenneth Katzman, Alfred Prados Analysts and Specialists in Middle...frustration that many Palestinians felt toward the peace process. This frustration erupted after Likud party head Ariel Sharon led a tour of al-Haram ash...and former defense minister Ariel Sharon led a Likud party Knesset contingent, guarded by 1,000 riot-gear clad Israeli police, on a tour of al-Haram

  11. Multiscale Modeling of Armor Ceramics: Focus on AlON

    DTIC Science & Technology

    2011-09-01

    with a focus on an optically transparent armor ceramic, polycrystalline (~200 µm grain size) aluminum oxynitride (AlON) spinel, that uses a multiscale...ceramic, polycrystalline (~200 m grain size) aluminum oxynitride (AlON) spinel, that uses a multiscale modeling approach, and will overview the...properties of aluminum oxynitride spinel (AlON) at high pressure (up to 40 GPa) have been calculated from first principles. We have assumed an

  12. Characterization and Evaluation of TiB2-AlN Composites for Armor Applications

    DTIC Science & Technology

    2013-09-01

    AlN A N AlN, AlB2, α-AlB12, β-AlB10, TiN, Ti2N, h-BN, c-BN, TiB2, Ti3B4 and TiB Ti3Al, TiAl , TiAl2, Ti3Al5 and TiAl3 Ti2AlN and Ti3AlN...the velocity of the tungsten heave alloy penetrator. The error bars are the average absolute deviation. Although DOP tests were not conducted on all

  13. The cyclic oxidation resistance at 1200 C of beta-NiAl, FeAl, and CoAl alloys with selected third element additions

    NASA Technical Reports Server (NTRS)

    Barrett, C. A.; Titran, R. H.

    1992-01-01

    The intermetallic compounds Beta-NiAl, FeAl, and CoAl were tested in cyclic oxidation with selected third element alloy additions. Tests in static air for 200 1-hr cycles at 1200 C indicated by specific weight change/time data and x-ray diffraction analysis that the 5 at percent alloy additions did not significantly improve the oxidation resistance over the alumina forming baseline alloys without the additions. Many of the alloy additions were actually deleterious. Ta and Nb were the only alloy additions that actually altered the nature of the oxide(s) formed and still maintained the oxidation resistance of the protective alumina scale.

  14. Spectra of surface plasmon polariton enhanced electroluminescence from electroformed Al-Al{sub 2}O{sub 3}-Ag diodes

    SciTech Connect

    Hickmott, T. W.

    2015-03-07

    Narrow band-pass filters have been used to measure the spectral distribution of electroluminescent photons with energies between 1.8 eV and 3.0 eV from electroformed Al-Al{sub 2}O{sub 3}-Ag diodes with anodic Al{sub 2}O{sub 3} thicknesses between 12 nm and 18 nm. Electroforming of metal-insulator-metal (MIM) diodes is a non-destructive dielectric breakdown that results in a conducting channel in the insulator and changes the initial high resistance of the MIM diode to a low resistance state. It is a critical step in the development of resistive-switching memories that utilize MIM diodes as the active element. Electroforming of Al-Al{sub 2}O{sub 3}-Ag diodes in vacuum results in voltage-controlled negative resistance (VCNR) in the current-voltage (I-V) characteristics. Electroluminescence (EL) and electron emission into vacuum (EM) develop simultaneously with the current increase that results in VCNR in the I-V characteristics. EL is due to recombination of electrons injected at the Al-Al{sub 2}O{sub 3} interface with radiative defect centers in Al{sub 2}O{sub 3}. Measurements of EL photons between 1.8 eV and 3.0 eV using a wide band-pass filter showed that EL intensity is exponentially dependent on Al{sub 2}O{sub 3} thickness for Al-Al{sub 2}O{sub 3}-Ag diodes between 12 nm and 20 nm thick. Enhanced El intensity in the thinnest diodes is attributed to an increase in the spontaneous emission rate of recombination centers due to high electromagnetic fields generated in Al{sub 2}O{sub 3} when EL photons interact with electrons in Ag or Al to form surface plasmon polaritons at the Al{sub 2}O{sub 3}-Ag or Al{sub 2}O{sub 3}-Al interface. El intensity is a maximum at 2.0–2.2 eV for Al-Al{sub 2}O{sub 3}-Ag diodes with Al{sub 2}O{sub 3} thicknesses between 12 nm and 18 nm. EL in diodes with 12 nm or 14 nm of Al{sub 2}O{sub 3} is enhanced by factors of 8–10 over EL from a diode with 18 nm of Al{sub 2}O{sub 3}. The extent of EL enhancement in

  15. Spectra of surface plasmon polariton enhanced electroluminescence from electroformed Al-Al{sub 2}O{sub 3}-Ag diodes

    SciTech Connect

    Hickmott, T. W.

    2015-03-07

    Narrow band-pass filters have been used to measure the spectral distribution of electroluminescent photons with energies between 1.8 eV and 3.0 eV from electroformed Al-Al{sub 2}O{sub 3}-Ag diodes with anodic Al{sub 2}O{sub 3} thicknesses between 12 nm and 18 nm. Electroforming of metal-insulator-metal (MIM) diodes is a non-destructive dielectric breakdown that results in a conducting channel in the insulator and changes the initial high resistance of the MIM diode to a low resistance state. It is a critical step in the development of resistive-switching memories that utilize MIM diodes as the active element. Electroforming of Al-Al{sub 2}O{sub 3}-Ag diodes in vacuum results in voltage-controlledmore » negative resistance (VCNR) in the current-voltage (I-V) characteristics. Electroluminescence (EL) and electron emission into vacuum (EM) develop simultaneously with the current increase that results in VCNR in the I-V characteristics. EL is due to recombination of electrons injected at the Al-Al{sub 2}O{sub 3} interface with radiative defect centers in Al{sub 2}O{sub 3}. Measurements of EL photons between 1.8 eV and 3.0 eV using a wide band-pass filter showed that EL intensity is exponentially dependent on Al{sub 2}O{sub 3} thickness for Al-Al{sub 2}O{sub 3}-Ag diodes between 12 nm and 20 nm thick. Enhanced El intensity in the thinnest diodes is attributed to an increase in the spontaneous emission rate of recombination centers due to high electromagnetic fields generated in Al{sub 2}O{sub 3} when EL photons interact with electrons in Ag or Al to form surface plasmon polaritons at the Al{sub 2}O{sub 3}-Ag or Al{sub 2}O{sub 3}-Al interface. El intensity is a maximum at 2.0–2.2 eV for Al-Al{sub 2}O{sub 3}-Ag diodes with Al{sub 2}O{sub 3} thicknesses between 12 nm and 18 nm. EL in diodes with 12 nm or 14 nm of Al{sub 2}O{sub 3} is enhanced by factors of 8–10 over EL from a diode with 18 nm of Al{sub 2}O{sub 3}. The extent of EL

  16. Incorporating upper motor neuron health in ALS drug discovery.

    PubMed

    Dervishi, Ina; Ozdinler, P Hande

    2018-01-10

    Amyotrophic lateral sclerosis (ALS) is a complex disease, that affects the motor neuron circuitry. After consecutive failures in clinical trials for the past 20 years, edaravone was recently approved as the second drug for ALS. This generated excitement in the field revealed the need to improve preclinical assays for continued success. Here, we focus on the importance and relevance of upper motor neuron (UMN) pathology in ALS, and discuss how incorporation of UMN survival in preclinical assays will improve inclusion criteria for clinical trials and expedite the drug discovery effort in ALS and related motor neuron diseases. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. 75 FR 67950 - National Institutes of Health, et al.;

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-04

    ... Health, et al.; Notice of Consolidated Decision on Applications for Duty-Free Entry of Electron...: National Institutes of Health, Bethesda, MD 20892. Instrument: Electron Microscope. Manufacturer: JEOL...

  18. A predictive model for amyotrophic lateral sclerosis (ALS) diagnosis.

    PubMed

    Gupta, P K; Prabhakar, S; Sharma, S; Anand, A

    2012-01-15

    The clinical diagnosis of amyotrophic lateral sclerosis (ALS) usually takes several months. The delay in diagnosis compromises the effective therapeutic interventions. Therefore, the present study was aimed to develop a statistical model for predicting the risk of ALS at earlier stages for better management of ALS patients. The study recruited 44 sporadic ALS patients and 29 normal controls. Thirteen different independent variables (predictors) which were believed to be associated with ALS were included in the study. Forward stepwise (likelihood ratio) binary logistic regression was used to find significant variables and probability of disease prediction. The Hosmer-Lemeshow goodness of fit statistic (χ(2)=4.379, df=8, p=0.821) indicate the appropriateness of forward stepwise (likelihood ratio) binary logistic regression model. Serum chemokine ligand-2, chemokine ligand-2 mRNA, vascular endothelial growth factor-A mRNA, smoking and alcohol consumption are the independent variables found significant to predict risk of ALS (p<0.05). The current model yielded 93.2% sensitivity and 86.2% specificity with 90.4% overall validity of correct ALS prediction. Forward stepwise (likelihood ratio) binary logistic regression model is an accurate method to predict ALS in the presence of serum CCL2, CCL2 mRNA, VEGFA mRNA, smoking and alcohol consumption with high sensitivity and specificity. However, bed side diagnostic utility of these variables needs to be validated further in larger ALS cohorts. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Microstructure of the Al-La-Ni-Fe system

    SciTech Connect

    Vasil’ev, A. L.; Ivanova, A. G.; Bakhteeva, N. D.; Kolobylina, N. N.; Orekhov, A. S.; Presnyakov, M. Yu.; Todorova, E. V.

    2015-01-15

    The microstructure of alloys based on the Al-La-Ni-Fe system, which are characterized by a unique ability to form metal glasses and nanoscale composites in a wide range of compositions, has been investigated. Al{sub 85}Ni{sub 7}Fe{sub 4}La{sub 4} and Al{sub 85}Ni{sub 9}Fe{sub 2}La{sub 4} alloys have been analyzed by electron microscopy (including high-resolution scanning transmission electron microscopy), energy-dispersive X-ray microanalysis, electron diffraction (ED), and X-ray diffraction (XRD). It is found that, along with fcc Al and Al{sub 4}La (Al{sub 11}La{sub 3}) particles, these alloys contain a ternary phase Al{sub 3}Ni{sub 1−x}Fe{sub x} (sp. gr. Pnma) isostructural to the Al{sub 3}Ni phase and a quaternary phase Al{sub 8}Fe{sub 2−x}Ni{sub x}La isostructural to the Al{sub 8}Fe{sub 2}Eu phase (sp. gr. Pbam). The unit-cell parameters of the Al{sub 3}Ni{sub 1−x}Fe{sub x} and Al{sub 8}Fe{sub 2−x}Ni{sub x}La compounds, determined by ED and refined by XRD, are a = 0.664(1) nm, b = 0.734(1) nm, and c = 0.490(1) nm for Al{sub 3}Ni{sub 1−x}Fe{sub x} and a = 1.258(3) nm, b = 1.448(3) nm, and c = 0.405(8) nm for Al{sub 8}Fe{sub 2−x}Ni{sub x}La. In both cases Ni and Fe atoms are statistically arranged, and no ordering is found. Al{sub 8}Fe{sub 2−x}Ni{sub x}La particles contain inclusions in the form of Al{sub 3}Fe δ layers.

  20. Ultrafast bulk diffusion of AlH x in high-entropy dehydrogenation intermediates of NaAlH 4 [Highly mobile AlH x species and the dehydogenation kinetics of NaAlH 4

    DOE PAGES

    Zhang, Feng; Wood, Brandon C.; Wang, Yan; ...

    2014-07-21

    Using first-principles molecular dynamics (FPMD) and total-energy calculations, we demonstrate low-barrier bulk diffusion of Al-bearing species in γ-NaAlH 4, a recently proposed high-entropy polymorph of NaAlH 4. For charged AlH 4– and neutral AlH 3 vacancies, the computed barriers for diffusion are <0.1 eV, and we directly observe the predicted diffusive pathways in FPMD simulations at picosecond time scales. In contrast, such diffusion in the α phase is inaccessible to FPMD, consistent with much higher barriers. The transport behavior of γ-NaAlH 4, in addition to key dynamical and structural signatures, is consistent with experimental observations of high-mobility species, strongly supportingmore » the idea that an intermediate transition from the α phase to a high-entropy polymorph facilitates the hydrogen-releasing decomposition of NaAlH4. Lastly, our results provide an answer to longstanding questions regarding the responsible agent for the experimentally observed efficient Al transport during dehydrogenation and suggest that mass transport and phase transformation kinetics are coupled. Implications for understanding the (de)hydrogenation of undoped and catalyzed NaAlH 4 are discussed.« less

  1. Anisotropic etching of Al by a directed Cl2 flux

    NASA Technical Reports Server (NTRS)

    Efremow, N. N.; Geis, M. W.; Mountain, R. W.; Lincoln, G. A.; Randall, J. N.

    1986-01-01

    A new Al etching technique is described that uses an ion beam from a Kaufman ion source and a directed Cl2 flux. The ion beam is used primarily to remove the native oxide and to allow the Cl2 to spontaneously react with the Al film forming volatile Al2Cl6. By controlling both the flux equivalent pressure of Cl2 and the ion beam current, this etching technique makes possible the anisotropic etching of Al with etch rates from 100 nm/min to nearly 10 microns/min with a high degree of selectivity.

  2. al-Qaida Strategy, Ideology, Doctrine, and Media

    ScienceCinema

    Dr. Jarret Brachman

    2017-12-09

    Dr. Jarret Brachman, an internationally recognized al-Qaida specialist, author and public lecturer, shares his thoughts on a range of topics, including the differences involved in fighting insurgent groups versus terrorist organizations, the future of the global al-Qaida movement, and assessing America's efforts to combat al-Qaida. In his talk, Brachman focuses specifically on current trends in al-Qaida's military and messaging strategies, both from the perspective of the group's senior leadership and its regional commands. Presented on June 17, 2010.

  3. Comments on the papers recently published by Kalaivani et al.

    NASA Astrophysics Data System (ADS)

    Srinivasan, Bikshandarkoil R.; Narvekar, Kedar U.

    2016-04-01

    We argue that the so-called L-lysinium succinate 1 (Kalaivani et al. (2015) [16], zinc chloride doped L-lysinium succinate 2 (Kalaivani et al. (2015) [17], L-threonine phthalate 3 (Elberin Mary Theras et al. (2015) [18] and sodium acetate doped L-tyrosine 4 (Arthi et al. (2015) [19] are all dubious crystals. Taking compounds 1-4 as examples we show that EDAX is an inappropriate method for characterization of new materials based on elemental composition data.

  4. Interfacial impurities and the reaction between Si and evaporated Al

    NASA Technical Reports Server (NTRS)

    Best, J. S.; Mccaldin, J. O.

    1975-01-01

    As commonly formed, the interface between substrate Si and evaporated Al is laden with impurities. Subsequent heating causes modest dissolution of Si into solid Al, the dissolution morphology being influenced by the interface impurities. In the present experiments, the amount of Si dissolving was considerably enhanced, causing sufficient interface movement to carry most interfaces clear of the original impurities. Under these conditions, the Si/Al interface assumes, during brief heat treatment, a simple shape composed of a few 111 plane-type facets. Such Si/Al interfaces produced in situ should be useful for low-temperature solid-state growth of Si.

  5. Study of the Al m 26 ( d , p ) Al 27 Reaction and the Influence of the Al 26 0 + Isomer on the Destruction of Al 26 in the Galaxy

    SciTech Connect

    Almaraz-Calderon, S.; Rehm, K. E.; Gerken, N.

    2017-08-17

    The existence of 26Al (t 1/2 = 7.17 × 10 5 yr) in the interstellar medium provides a direct confirmation of ongoing nucleosynthesis in the Galaxy. The presence of a low-lying 0 + isomer ( 26Al m), however, severely complicates the astrophysical calculations. Here we present for the first time a study of the 26Al m (d, p) 27 Al reaction using an isomeric 26Al beam. The selectivity of this reaction allowed the study of ℓ = 0 transfers to T = 1/2, and T = 3/2 states in 27Al . Mirror symmetry arguments were then used to constrain themore » 26Al m (p,γ) 27Si reaction rate and provide an experimentally determined upper limit of the rate for the destruction of isomeric 26Al via radiative proton capture reactions, which is expected to dominate the destruction path of 26Al m in asymptotic giant branch stars, classical novae, and core collapse supernovae.« less

  6. On the microscopic dynamics of the 'Einstein solids' AlV2Al20 and GaV2Al20, and of YV2Al20: a benchmark system for 'rattling' excitations.

    PubMed

    Koza, Michael Marek; Mutka, Hannu; Okamoto, Yoshihiko; Yamaura, Jun-ichi; Hiroi, Zenji

    2015-10-14

    The inelastic response of AV2Al20 (with A = Al, Ga and Y) was probed by high-resolution inelastic neutron scattering experiments and density functional theory (DFT) based lattice dynamics calculations (LDC). Features characteristic of the dynamics of Al, Ga and Y are established experimentally in the low-energy range of the compounds. In the stereotype 'Einstein-solid' compound AlV2Al20 we identify a unique spectral density extending up to 10 meV at 1.6 K. Its dominating feature is a peak centred at 2 meV at the base temperature. A very similar spectral distribution is established in GaV2Al20 albeit the strong peak is located at 1 meV at 1.6 K. In YV2Al20 signals characteristic of Y dynamics are located above 8 meV. The spectral distributions are reproduced by the DFT-based LDC and identified as a set of phonons. The response to temperature changes between 1.6 and ∼300 K is studied experimentally and the exceptionally vivid renormalization of the A characteristic modes in AlV2Al20 and GaV2Al20 is quantified by following the energy of the strong peak. At about 300 K it is shifted to higher energies by 300% for A = Al and 450% for A = Ga. The dynamics of A = Y in YV2Al20 show a minor temperature effect. This holds in general for modes located above 10 meV in any of the compounds. They are associated with vibrations of the V2Al20 matrix. Atomic potentials derived through DFT calculations indicate the propensity of A = Al and Ga to a strong positive energy shift upon temperature increase by a high quartic component. The effect of the strong phonon renormalization on thermodynamic observables is computed on grounds of the LDC results. It is shown that through the hybridization of A = Al and Ga with the V2Al20 dynamics the matrix vibrations in the low-energy range follow this renormalization.

  7. Elastic properties of Al2O3-NiAl: a modified version of Hashin-Shtrikman bounds

    NASA Astrophysics Data System (ADS)

    Upadhyay, Anupama; Beniwal, R. S.; Singh, Ramvir

    2012-05-01

    The modified nonlinear relations for the estimation of elastic constants of Al2O3-NiAl composite material are developed. The concept of microstructure and interconnectivity of phases at the interface is used. Hashin-Shtrikman relations are described in their actual form and modified version of Hashin-Shtrikman relations for bulk and shear moduli are discussed. These relations for elastic and mechanical properties are applied mainly for Al2O3-NiAl composite material. Theoretical predictions using modified relations are compared with Hashin-Shtrikman bounds and experimental results of elastic properties for Al2O3-NiAl matrix-inclusion-based composite. It is found that the predicted values of elastic and mechanical properties using modified relations are quite close to the experimental results.

  8. Inductively coupled BCl 3/Cl 2 /Ar plasma etching of Al-rich AlGaN

    DOE PAGES

    Douglas, Erica A.; Sanchez, Carlos A.; Kaplar, Robert J.; ...

    2016-12-01

    Varying atomic ratios in compound semiconductors is well known to have large effects on the etching properties of the material. The use of thin device barrier layers, down to 25 nm, adds to the fabrication complexity by requiring precise control over etch rates and surface morphology. The effects of bias power and gas ratio of BCl 3 to Cl 2 for inductively coupled plasma etching of high Al content AlGaN were contrasted with AlN in this study for etch rate, selectivity, and surface morphology. Etch rates were greatly affected by both bias power and gas chemistry. Here we detail themore » effects of small variations in Al composition for AlGaN and show substantial changes in etch rate with regards to bias power as compared to AlN.« less

  9. Microstructure Evolution of Cold-Sprayed Al-Si Alloy Coatings on γ-TiAl During Heat Treatment

    NASA Astrophysics Data System (ADS)

    Wang, Jiqiang; Kong, Lingyan; Li, Tiefan; Xiong, Tianying

    2015-08-01

    This paper investigated the influence of heat treatment on the microstructure of Al-Si alloy coatings on γ-TiAl alloy. The coatings were prepared by cold spraying with Al-12Si and Al-20Si alloy powders as the feedstock, and then the as-sprayed coatings were subjected to heat treatment. The microstructure, chemical composition, and phase transformation of the coatings were studied by SEM, XRD, and EPMA. The diffusing behavior of Al and Si during heat treatment was investigated. The results showed that a silicon-aluminizing coating was formed through the inward diffusion of Al/Si elements into the substrate. The obtained kinetics curve of the formation of silicon-aluminizing coating at 580 °C similarly followed parabolic law.

  10. HRTEM image contrast and atomistic microstructures of long-period ordered Al-rich TiAl alloys.

    PubMed

    Hata, Satoshi; Higuchi, Kiyoshi; Mitate, Toshitsugu; Itakura, Masaru; Tomokiyo, Yoshitsugu; Kuwano, Noriyuki; Nakano, Takayoshi; Nagasawa, Yosuke; Umakoshi, Yukichi

    2004-01-01

    Long-period superstructures formed in off-stoichiometric L 1(0)-TiAl alloys were investigated by high-resolution transmission electron microscopy (HRTEM). The HRTEM analysis combined with multislice simulation and image processing was carried out to clarify atomistic microstructures of Al5Ti3 and h-Al2Ti ordered states and a short-range ordered (SRO) state in Ti-62.5 at.% Al alloys. Aluminium atoms in the (002) Ti layers form square-, lean rhombus- and fat rhombus-type ordered clusters in the SRO state. The ordered clusters are in contact with each other and form microdomains of various long-period superstructures. The ordered clusters are tiled periodically in a long range to form Al5Ti3 or h-Al2Ti domains and characteristic antiphase boundary structures.

  11. IBA analysis and corrosion resistance of TiAlPtN/TiAlN/TiAl multilayer films deposited over a CoCrMo using magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Canto, C. E.; Andrade, E.; de Lucio, O.; Cruz, J.; Solís, C.; Rocha, M. F.; Alemón, B.; Flores, M.; Huegel, J. C.

    2016-03-01

    The corrosion resistance and the elemental profile of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by Physical Vapor Deposition (PVD) reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt to enhance the corrosion resistance of a biomedical alloy of CoCrMo. Corrosion tests were performed using Simulated Body Fluid (SBF) using potentiodynamic polarization tests at typical body temperature. The elemental composition and thickness of the coatings were evaluated with the combination of two ion beam analysis (IBA) techniques: a Rutherford Backscattering Spectroscopy (RBS) with alpha beam and a Nuclear Reaction Analysis with a deuteron beam.

  12. Growth Kinetics of γ-Al12Mg17 and β-Al3Mg2 Intermetallic Phases in Mg vs. Al Diffusion Couples

    NASA Astrophysics Data System (ADS)

    Brennan, Sarah; Bermudez, Katrina; Kulkarni, Nagraj; Sohn, Yongho

    Increasing use and development of lightweight Mg-alloys have led to the desire for more fundamental research in and understanding of Mg-based systems. As a strengthening component, Al is one of the most important and common alloying elements for Mg-alloys. In this study, solid-to-solid diffusion couple techniques were employed to examine the interdiffusion between pure Mg and Al. Diffusion anneals were carried out at 300°, 350°, and 400°C for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopies (SEM) were employed to observe the formation of the intermetallics γ-Al12Mg17 and β-Al3Mg2, but not ɛ-phase. Concentration profiles were determined using X-ray energy dispersive spectroscopy (XEDS). The growth constants and activation energies were determined for each intermetallic phase.

  13. Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

    NASA Astrophysics Data System (ADS)

    Li, Shuo; Bhushan, Bharat

    2016-08-01

    Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

  14. Observation of overstrain in the coalescence zone of AlAs/AlOx oxidation fronts

    NASA Astrophysics Data System (ADS)

    Chouchane, F.; Almuneau, G.; Gauthier-Lafaye, O.; Monmayrant, A.; Arnoult, A.; Lacoste, G.; Fontaine, C.

    2011-06-01

    Strain from oxidation-induced volume shrinkage is studied by micro-photoluminescence. An InGaAs/GaAs quantum well (QW) placed at the vicinity of the selectively oxidized AlAs layer is used to probe the spatial distribution of the strain with a resolution of 1 µm. A QW wavelength shift of 1 nm imputed to the embedded strain is observed in agreement with finite element calculations. With this method, an overstrained zone is highlighted where the counter-propagative oxidation fronts merge.

  15. Comparative research on the influence of varied Al component on the active layer of AlGaN photocathode

    NASA Astrophysics Data System (ADS)

    He, Minyou; Chen, Liang; Su, Lingai; Yin, Lin; Qian, Yunsheng

    2017-06-01

    To theoretically research the influence of a varied Al component on the active layer of AlGaN photocathodes, the first principle based on density functional theory is used to calculate the formation energy and band structure of Al x Ga1-x N with x at 0, 0.125, 0.25, 0.325, and 0.5. The calculation results show that the formation energy declines along with the Al component rise, while the band gap is increasing with Al component increasing. Al x Ga1-x N with x at 0, 0.125, 0.25, 0.325, and 0.5 are direct band gap semiconductors, and their absorption coefficient curves have the same variation tendency. For further study, we designed two kinds of reflection-mode AlGaN photocathode samples. Sample 1 has an Al x Ga1-x N active layer with varied Al component ranging from 0.5 to 0 and decreasing from the bulk to the surface, while sample 2 has an Al x Ga1-x N active layer with the fixed Al component of 0.25. Using the multi-information measurement system, we measured the spectral response of the activated samples at room temperature. Their photocathode parameters were obtained by fitting quantum efficiency curves. Results show that sample 1 has a better spectral response than sample 2 at the range of short-wavelength. This work provides a reference for the structure design of the AlGaN photocathode. Project supported by the National Natural Science Foundation of China (Nos. 61308089, 6144005) and the Public Technology Applied Research Project of Zhejiang Province (No. 2013C31068).

  16. AlGaN-based deep UV LEDs grown on sputtered and high temperature annealed AlN/sapphire

    NASA Astrophysics Data System (ADS)

    Susilo, Norman; Hagedorn, Sylvia; Jaeger, Dominik; Miyake, Hideto; Zeimer, Ute; Reich, Christoph; Neuschulz, Bettina; Sulmoni, Luca; Guttmann, Martin; Mehnke, Frank; Kuhn, Christian; Wernicke, Tim; Weyers, Markus; Kneissl, Michael

    2018-01-01

    The performance characteristics of AlGaN-based deep ultraviolet light emitting diodes (UV-LEDs) grown by metalorganic vapor phase epitaxy on sputtered and high temperature annealed AlN/sapphire templates are investigated and compared with LEDs grown on epitaxially laterally overgrown (ELO) AlN/sapphire. The structural and electro-optical properties of the devices on 350 nm sputtered and high temperature annealed AlN/sapphire show similar defect densities and output power levels as LEDs grown on low defect density ELO AlN/sapphire templates. After high temperature annealing of the 350 nm sputtered AlN, the full widths at half maximum of the (0002) and (10 1 ¯ 2 ) reflections of the high resolution x-ray diffraction rocking curves decrease by one order of magnitude to 65 arc sec and 240 arc sec, respectively. The curvature of the sputtered and HTA AlN/sapphire templates after regrowth with 400 nm MOVPE AlN is with -80 km-1 much lower than the curvature of the ELO AlN/sapphire template of -160 km-1. The on-wafer measured output powers of 268 nm LEDs grown on 350 nm sputtered and high temperature annealed AlN/sapphire templates and ELO AlN/sapphire templates were 0.70 mW and 0.72 mW at 20 mA, respectively (corresponding to an external quantum efficiency of 0.75% and 0.78%). These results show that sputtered and high temperature annealed AlN/sapphire provide a viable approach for the fabrication of efficient UVC-LEDs with reduced complexity and thus reduced costs.

  17. Probing the Dielectric Properties of Ultrathin Al/Al2O3/Al Trilayers Fabricated Using in Situ Sputtering and Atomic Layer Deposition.

    PubMed

    Acharya, Jagaran; Wilt, Jamie; Liu, Bo; Wu, Judy

    2018-01-24

    Dielectric properties of ultrathin Al 2 O 3 (1.1-4.4 nm) in metal-insulator-metal (M-I-M) Al/Al 2 O 3 /Al trilayers fabricated in situ using an integrated sputtering and atomic layer deposition (ALD) system were investigated. An M-I interfacial layer (IL) formed during the pre-ALD sample transfer even under high vacuum has a profound effect on the dielectric properties of the Al 2 O 3 with a significantly reduced dielectric constant (ε r ) of 0.5-3.3 as compared to the bulk ε r ∼ 9.2. Moreover, the observed soft-type electric breakdown suggests defects in both the M-I interface and the Al 2 O 3 film. By controlling the pre-ALD exposure to reduce the IL to a negligible level, a high ε r up to 8.9 was obtained on the ALD Al 2 O 3 films with thicknesses from 3.3 to 4.4 nm, corresponding to an effective oxide thickness (EOT) of ∼1.4-1.9 nm, respectively, which are comparable to the EOTs found in high-K dielectrics like HfO 2 at 3-4 nm in thickness and further suggest that the ultrathin ALD Al 2 O 3 produced in optimal conditions may provide a low-cost alternative gate dielectric for CMOS. While ε r decreases at a smaller Al 2 O 3 thickness, the hard-type dielectric breakdown at 32 MV/cm and in situ scanning tunneling spectroscopy revealed band gap ∼2.63 eV comparable to that of an epitaxial Al 2 O 3 film. This suggests that the IL is unlikely a dominant reason for the reduced ε r at the Al 2 O 3 thickness of 1.1-2.2 nm but rather a consequence of the electron tunneling as confirmed in the transport measurement. This result demonstrates the critical importance in controlling the IL to achieving high-performance ultrathin dielectric in MIM structures.

  18. Liver X Receptor Genes Variants Modulate ALS Phenotype.

    PubMed

    Mouzat, Kevin; Molinari, Nicolas; Kantar, Jovana; Polge, Anne; Corcia, Philippe; Couratier, Philippe; Clavelou, Pierre; Juntas-Morales, Raul; Pageot, Nicolas; Lobaccaro, Jean -Marc A; Raoul, Cedric; Lumbroso, Serge; Camu, William

    2017-02-27

    Amyotrophic lateral sclerosis (ALS) is one of the most severe motor neuron (MN) disorders in adults. Phenotype of ALS patients is highly variable and may be influenced by modulators of energy metabolism. Recent works have implicated the liver X receptors α and β (LXRs), either in the propagation process of ALS or in the maintenance of MN survival. LXRs are nuclear receptors activated by oxysterols, modulating cholesterol levels, a suspected modulator of ALS severity. In a cohort of 438 ALS patients and 330 healthy controls, the influence of LXR genes on ALS risk and phenotype was studied using single nucleotide polymorphisms (SNPs). The two LXRα SNPs rs2279238 and rs7120118 were shown to be associated with age at onset in ALS patients. Consistently, homozygotes were twice more correlated than were heterozygotes to delayed onset. The onset was thus delayed by 3.9 years for rs2279238 C/T carriers and 7.8 years for T/T carriers. Similar results were obtained for rs7120118 (+2.1 years and +6.7 years for T/C and C/C genotypes, respectively). The LXRβ SNP rs2695121 was also shown to be associated with a 30% increase of ALS duration (p = 0.0055, FDR = 0.044). The tested genotypes were not associated with ALS risk. These findings add further evidence to the suspected implication of LXR genes in the disease process of ALS and might open new perspectives in ALS therapeutics.

  19. al-Khwarizmi [al-Khawarizmi; al'Khwarizmi], Abu Abd-Allah [Abdullah; Ja'far] Mohammad [Muhammad] ibn Musa [Bin Musa] (c. 800-c. 850)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Born at Khawarizm (Kheva), south of the Aral Sea, he flourished in Baghdad from 813 to 833. He was an astronomer and geographer but is best known as a mathematician. The word algebra was derived from his book Al-Jabr wa-al-Muqabilah. He brought into mathematics the use of zero and the rest of the Indian system of numerals (now known as `Arabic numerals'), and developed the decimal system. His nam...

  20. Laser irradiation of ZnO:Al/Ag/ZnO:Al multilayers for electrical isolation in thin film photovoltaics

    PubMed Central

    2013-01-01

    Laser irradiation of ZnO:Al/Ag/ZnO:Al transparent contacts is investigated for segmentation purposes. The quality of the irradiated areas has been experimentally evaluated by separation resistance measurements, and the results are complemented with a thermal model used for numerical simulations of the laser process. The presence of the Ag interlayer plays two key effects on the laser scribing process by increasing the maximum temperature reached in the structure and accelerating the cool down process. These evidences can promote the use of ultra-thin ZnO:Al/Ag/ZnO:Al electrode in large-area products, such as for solar modules. PMID:24053228

  1. Microstructural investigations on as-cast and annealed Al-Sc and Al-Sc-Zr alloys

    SciTech Connect

    Lohar, A.K., E-mail: adityalohar@yahoo.co.in; Mondal, B.; Rafaja, D.

    2009-11-15

    Al-Sc and Al-Sc-Zr alloys containing 0.05, 0.1 and 0.5 wt.% Sc and 0.15 wt.% Zr were investigated using optical microscopy, electron microscopy and X-ray diffraction. The phase composition of the alloys and the morphology of precipitates that developed during solidification in the sand casting process and subsequent thermal treatment of the samples were studied. XRD analysis shows that the weight percentage of the Al{sub 3}Sc/Al{sub 3}(Sc, Zr) precipitates was significantly below 1% in all alloys except for the virgin Al0.5Sc0.15Zr alloy. In this alloy the precipitates were observed as primary dendritic particles. In the binary Al-Sc alloys, ageing at 470more » deg. C for 24 h produced precipitates associated with dislocation networks, whereas the precipitates in the annealed Al-Sc-Zr alloys were free of interfacial dislocations except at the lowest content of Sc. Development of large incoherent precipitates during precipitation heat treatment reduced hardness of all the alloys studied. Growth of the Al{sub 3}Sc/Al{sub 3}(Sc, Zr) precipitates after heat treatment was less at low Sc content and in the presence of Zr. Increase in hardness was observed after heat treatment at 300 deg. C in all alloys. There is a small difference in hardness between binary and ternary alloys slow cooled after sand casting.« less

  2. How well can wave runup be predicted? comment on Laudier et al. (2011) and Stockdon et al. (2006)

    USGS Publications Warehouse

    Plant, Nathaniel G.; Stockdon, Hilary F.

    2015-01-01

    Laudier et al. (2011) suggested that there may be a systematic bias error in runup predictions using a model developed by Stockdon et al. (2006). Laudier et al. tested cases that sampled beach and wave conditions that differed from those used to develop the Stockdon et al. model. Based on our re-analysis, we found that in two of the three Laudier et al. cases observed overtopping was actually consistent with the Stockdon et al. predictions. In these cases, the revised predictions indicated substantial overtopping with, in one case, a freeboard deficit of 1 m. In the third case, the revised prediction had a low likelihood of overtopping, which reflected a large uncertainty due to wave conditions that included a broad and bi-modal frequency distribution. The discrepancy between Laudier et al. results and our re-analysis appear to be due, in part, to simplifications made by Laudier et al. when they implemented a reduced version of the Stockdon et al. model.

  3. Evolution of Fe Bearing Intermetallics During DC Casting and Homogenization of an Al-Mg-Si Al Alloy

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Grant, P. S.; O'Reilly, K. A. Q.

    2016-06-01

    The evolution of iron (Fe) bearing intermetallics (Fe-IMCs) during direct chill casting and homogenization of a grain-refined 6063 aluminum-magnesium-silicon (Al-Mg-Si) alloy has been studied. The as-cast and homogenized microstructure contained Fe-IMCs at the grain boundaries and within Al grains. The primary α-Al grain size, α-Al dendritic arm spacing, IMC particle size, and IMC three-dimensional (3D) inter-connectivity increased from the edge to the center of the as-cast billet; both α c-AlFeSi and β-AlFeSi Fe-IMCs were identified, and overall α c-AlFeSi was predominant. For the first time in industrial billets, the different Fe-rich IMCs have been characterized into types based on their 3D chemistry and morphology. Additionally, the role of β-AlFeSi in nucleating Mg2Si particles has been identified. After homogenization, α c-AlFeSi predominated across the entire billet cross section, with marked changes in the 3D morphology and strong reductions in inter-connectivity, both supporting a recovery in alloy ductility.

  4. Motor neurons derived from ALS-related mouse iPS cells recapitulate pathological features of ALS.

    PubMed

    Park, Ju-Hwang; Park, Hang-Soo; Hong, Sunghoi; Kang, Seongman

    2016-12-09

    Amyotrophic lateral sclerosis (ALS) is a late-onset progressive neurodegenerative disease characterized by the loss of motor neurons in the spinal cord and brain. Mutations in Cu/Zn superoxide dismutase 1 (SOD1) are known to induce ALS. Although many research models have been developed, the exact pathological mechanism of ALS remains unknown. The recently developed induced pluripotent stem (iPS) cell technology is expected to illuminate the pathological mechanisms and new means of treatment for neurodegenerative diseases. To determine the pathological mechanism of ALS, we generated mouse iPS (miPS) cells from experimental ALS transgenic mice and control mice and characterized the cells using molecular biological methods. The generated miPS cells expressed many pluripotent genes and differentiated into three germ layers in vitro and in vivo. Motor neurons derived from ALS-related miPS cells recapitulated the pathological features of ALS. The ALS-model motor neurons showed SOD1 aggregates, as well as decreased cell survival rate and neurite length compared with wild-type motor neurons. Our study will be helpful in revealing the mechanism of motor neuronal cell death in ALS.

  5. Oxidation Resistant Ti-Al-Fe Diffusion Barrier for FeCrAlY Coatings on Titanium Aluminides

    NASA Technical Reports Server (NTRS)

    Brady, Michael P. (Inventor); Smialke, James L. (Inventor); Brindley, William J. (Inventor)

    1996-01-01

    A diffusion barrier to help protect titanium aluminide alloys, including the coated alloys of the TiAl gamma + Ti3Al (alpha2) class, from oxidative attack and interstitial embrittlement at temperatures up to at least 1000 C is disclosed. The coating may comprise FeCrAlX alloys. The diffusion barrier comprises titanium, aluminum, and iron in the following approximate atomic percent: Ti-(50-55)Al-(9-20)Fe. This alloy is also suitable as an oxidative or structural coating for such substrates.

  6. Reviewing the class of Al-rich Ti-Al alloys: modeling high temperature plastic anisotropy and asymmetry

    NASA Astrophysics Data System (ADS)

    Chowdhury, Helal; Altenbach, Holm; Krüger, Manja; Naumenko, Konstantin

    2017-12-01

    In the last decades, the class of Ti-rich TiAl-based intermetallic materials has replaced many contemporary alloys till 900 °C. Due to higher oxidation resistance, 20% lower density and higher (about 150 °C more) operating temperature possibility of Al-rich TiAl alloys over Ti-rich side, phases from the Al-rich region of this alloy system are considered to be highly potential candidates for high temperature structural applications. Although there are a lot of works about Ti-rich alloys, however, investigation from the Al-rich side is very limited. This work reviews the class of Al-rich TiAl alloys in terms of phases, microstructures, morphology, deformation mechanisms, mechanical behaviors along with a possible micromechanical modeling approach. Single crystal like Ti-61.8at.%Al alloy from the Al-rich family has been chosen as an example for modeling high temperature anisotropy and tension-compression asymmetry. A possible comparison with Ti-rich side is also presented.

  7. Initial gas phase reactions between Al(CH3)3/AlH3 and ammonia: theoretical study.

    PubMed

    Lisovenko, Anna S; Morokuma, Keiji; Timoshkin, Alexey Y

    2015-01-29

    Mechanisms of initial stages of gas phase reactions between trimethylaluminum and ammonia have been explored by DFT studies. Subsequent substitution of CH3 groups in AlMe3 by amido groups and substitution of hydrogen atoms in ammonia by AlMe2 groups have been considered. Structures of Al(CH3)x(NH2)3-x, NHx(Al(CH3)2)3-x (x = 0-3) and related donor-acceptor complexes, dimerization products, and reaction pathways for the methane elimination have been obtained. The transition state for the first methane elimination from Al(CH3)3NH3 adduct is the highest point on the reaction pathway; subsequent processes are exothermic and do not require additional activation energy. In excess ammonia, subsequent methane elimination reactions may lead to formation of [Al(NH2)3]2, while in excess trimethylaluminum, formation of N(AlMe2)3 is feasible. Formation of [AlMe2NH2]2 dimer is very favorable thermodynamically. Studies on model reactions between AlH3 and NH3 indicate that reaction barriers obtained for hydrogen-substituted species may serve as an upper estimate in studying the reactivity of methyl-substituted analogues in more complex systems.

  8. Magnetic phase transitions in TbFe2Al10, HoFe2Al10 and ErFe2Al10

    NASA Astrophysics Data System (ADS)

    Reehuis, M.; Wolff, M. W.; Krimmel, A.; Scheidt, E.-W.; Stüsser, N.; Loidl, A.; Jeitschko, W.

    2003-03-01

    The magnetic order of the orthorhombic aluminides TbFe2Al10, HoFe2Al10 and ErFe2Al10 (space group Cmcm) has been studied by specific heat and magnetic measurements, as well as by neutron powder diffraction down to 100 mK and in external fields up to 5 T. Only the rare-earth ions carry a magnetic moment. At T = 1.5 K the terbium moments in TbFe2Al10 show a square-wave modulated magnetic order with wavevector k = (0, 0.7977, 0) and a moment direction parallel to the a-axis. At a critical field of Hc1 = 0.9 T one of ten spins is forced to flip, going into an intermediate ferrimagnetic phase that is stable up to the critical field Hc2 = 1.8 T. Above this field finally all the rest of the spins flip, resulting in a ferromagnetic order of the terbium moments. ErFe2Al10 orders antiferromagnetically below TN = 1.77(7) K with a similar magnetic structure characterized by a wavevector k = (0, ~ 0.8, 0). In contrast, no signs of long range magnetic order could be observed for HoFe2Al10 down to 100 mK.

  9. GaN/AlGaN ultraviolet light-emitting diode with an embedded porous-AlGaN distributed Bragg reflector

    NASA Astrophysics Data System (ADS)

    Wang, Guan-Jhong; Hong, Bo-Syun; Chen, Yi-Yun; Yang, Zhong-Jie; Tsai, Tzong-Liang; Lin, Yung-Sen; Lin, Chia-Feng

    2017-12-01

    A GaN/AlGaN-based ultraviolet light-emitting diode (LED) structure with an embedded porous-AlGaN reflector was fabricated by a doping-selective electrochemical (EC) wet-etching process. The n+-AlGaN/undoped-AlGaN (u-AlGaN) stack structures with different Al contents were transformed into porous-AlGaN/u-AlGaN stack structures that acted as the embedded distributed Bragg reflectors (DBRs). The porosity of the EC-treated AlGaN layer was increased by decreasing the Al content in the n+-AlGaN layer. The reflectivity of the porous-AlGaN DBR structure was measured to be 90% at 379.3 nm with a 37.2 nm stopband width. The photoluminescence emission intensity of the DBR-LED was enhanced by forming the embedded porous-AlGaN DBR structure.

  10. Structure of molten Al and eutectic Al-Si alloy studied by neutron diffraction

    SciTech Connect

    Dahlborg, U.; Kramer, Matthew J.; Besser, M.; Morris, J. R.; Calvo-Dahlborg, M.

    2012-11-24

    The structure of molten eutectic Al87.8Si12.2 alloy has been studied by neutron diffraction during a temperature cycle. For comparison measurements were performed on pure molten Al. The measurements show that the alloy after heating above the liquidus contains particles of two kinds, aluminum-rich and silicon-rich. The silicon-rich particles are partly dissolved after a further heating. Earlier published data obtained by the γ-ray absorption technique of the density of the molten eutectic Al–Si alloy had demonstrated the existence of two temperatures above the liquidus temperature: A dissolution temperature Td, at which the microstructure of the melt inherited from the ingot starts to dissolve and a branching temperature, Tb, at which the melt reaches a fully mixed state. The highest temperature that was possible to reach during the neutron experiments lies between Td and Tb. The obtained results support these conclusions that molten alloys after melting are inhomogeneous up to a temperature well above the liquidus. Moreover, the difference in shape between the static structure factors measured by neutron and X-ray diffraction on molten aluminum is observed and is found to be more accentuated and to extend to larger wavevectors than in earlier works.

  11. Cooperation or dolphin 'tug-of-war'? Comment on Kuczaj et al. and Eskelinen et al.

    PubMed

    King, Stephanie L; Allen, Simon J; Connor, Richard C; Jaakkola, Kelly

    2016-11-01

    Two recent papers by Kuczaj et al. (Anim Cognit 18:543-550, 2015) and Eskelinen et al. (Anim Cognit 19:789-797, 2016) claim to have demonstrated that (i) bottlenose dolphins (Tursiops truncatus) cooperated to solve a novel task and (ii) vocal signals were important for coordinating these cooperative efforts. Although it is likely that bottlenose dolphins may share communicative signals in order to achieve a common goal, we suggest that this has not been demonstrated in the aforementioned studies. Here, we discuss the two main problems that preclude any definitive conclusions being drawn on cooperative task success and vocal communication from these studies. The first lies in the experimental design. The 'cooperative task', involving an apparatus that requires two dolphins to pull in opposite directions in order to achieve a food reward, is not conducive to cooperation, but could instead reflect a competitive 'tug-of-war'. It is therefore of questionable use in distinguishing competitive from cooperative interactions. Second, the suggestion that the occurrence of burst-pulsed signals in this task was indicative of cooperation is disputable, as (i) this study could not determine which dolphins were actually producing the signals and (ii) this sound type is more commonly associated with aggressive signalling in dolphins. We commend the authors for investigating this exciting and topical area in animal communication and cognition, but the question of whether dolphins cooperate and communicate to solve a cooperative task remains as yet unanswered.

  12. Molten Al and (0001) α-Al2O3 Single Crystal: Interface Stability

    NASA Astrophysics Data System (ADS)

    Aguilar-santillan, Joaquin

    2016-10-01

    The roughness on the " c"-plane (0001) sapphire single crystal reduces wetting of molten aluminum under Ar gas (99.999 pct) and PO2 10-15 Pa from 1073 K to 1473 K (800 °C to 1200 °C). The contact angle effect was partially understood by the roughness factor, R; however, the interfacial phenomenon involving this effect is yet a topic to study as it also depends, between other things, on the shape of droplet and the relationship to its substrate. The theory explains that the surface tension of liquid aluminum obtained by the sessile drop test can be determined just when a substrate is polished or free of any surface imperfection. However, roughness of sapphire (0001) surface promotes an apparent surface tension that exhibits different trends of wetting to that proposed in previous studies. This property adds to the interfacial wetting phenomena obtained from the Al-Al2O3 couple system and provides answers for contact angle trends toward a much more stable interface, which when coupled with thermodynamic conditions may help in the manufacturing, deterioration, and reliability of the system.

  13. ENERGY CONVERSION FOR THE TRANSITION FROM Al TO γ-Al2O3 NANOPARTICLES

    NASA Astrophysics Data System (ADS)

    Wang, Shulin; Li, Shengjuan; Xu, Bo; Jian, Dunliang; Zhu, Yufang

    2013-07-01

    We have successfully converted large volume Al particles into γ-Al2O3 nanostructures by vibration milling at room temperature and successive treatment. We show that there exist special relationships among stacking fault energy (SFE), strain energy (SRE), and surface energy (SE) of the materials, including interdependence, intercompetition, and interconversion during the phase transition. SFE and SRE perform the same changing tendency, while SE just does the opposite. However, it is not the particle size but the energy state that determines the reactivity of the materials. And it is the SE that can directly determine the physical chemical reaction and the conversion into the end product rather than SFE and SRE. When SE goes up, the material reactivity and the product yield will be enhanced; and when SE goes down, the reaction and the product yield will decay. However, the state of SE depends closely on the change tendency of the SFE and SRE. That is, when SFE and SRE goes up, SE will goes down; if SFE and SRE goes down, SE will goes up. It seems that energy conservation law may be followed in a sense in the particle system if the external input keeps constant. The work may be significant for energy conversion in nano-scale and mechanosynthesis of oxide nanoparticles.

  14. Fabrication of Al-Al₃Ti/Ti₃Al Functionally Graded Materials under a Centrifugal Force.

    PubMed

    El-Hadad, Shimaa; Sato, Hisashi; Miura-Fujiwara, Eri; Watanabe, Yoshimi

    2010-09-08

    Fabrication of Al-Al₃Ti functionally graded materials (FGMs) under the centrifugal force has recently attracted some attention. The controlled compositional gradient of the fabricated FGMs, the low cost of the process, and the good mold filling, are the main advantages of the centrifugal method (CM). Using the conventional CM techniques such as the centrifugal solid-particle method and centrifugal in-situ method, FGMs rings with gradually distributed properties could be achieved. As a more practical choice, the centrifugal mixed-powder method (CMPM) was recently proposed to obtain FGMs containing nano-particles selectively dispersed in the outer surface of the fabricated parts. However, if a control of the particles morphology, compound formulas or sizes, is desired, another CM technique is favored. As a development of CMPM, our novel reaction centrifugal mixed-powder method (RCMPM) has been presented. Using RCMPM, Al‑Al₃Ti/Ti₃Al FGMs with good surface properties and temperature controlled compositional gradient could be achieved. In this short review, this novel method will be discussed in detail and the effect of RCMPM processing temperature on the reinforcement particles morphology, size and distribution through the fabricated samples, will be reviewed.

  15. Structure of molten Al and eutectic Al-Si alloy studied by neutron diffraction

    SciTech Connect

    Dahlborg, U.; Kramer, Matthew J.; Besser, M.

    2012-11-24

    The structure of molten eutectic Al87.8Si12.2 alloy has been studied by neutron diffraction during a temperature cycle. For comparison measurements were performed on pure molten Al. The measurements show that the alloy after heating above the liquidus contains particles of two kinds, aluminum-rich and silicon-rich. The silicon-rich particles are partly dissolved after a further heating. Earlier published data obtained by the γ-ray absorption technique of the density of the molten eutectic Al–Si alloy had demonstrated the existence of two temperatures above the liquidus temperature: A dissolution temperature Td, at which the microstructure of the melt inherited from the ingot startsmore » to dissolve and a branching temperature, Tb, at which the melt reaches a fully mixed state. The highest temperature that was possible to reach during the neutron experiments lies between Td and Tb. The obtained results support these conclusions that molten alloys after melting are inhomogeneous up to a temperature well above the liquidus. Moreover, the difference in shape between the static structure factors measured by neutron and X-ray diffraction on molten aluminum is observed and is found to be more accentuated and to extend to larger wavevectors than in earlier works.« less

  16. The Microstructure, Texture and Mechanical Properties of the Rolled Al/Mg/Al Clad Sheets

    NASA Astrophysics Data System (ADS)

    Nie, Huihui; Liang, Wei; Zheng, Liuwei; Ren, Xiaoxia; Chi, Chengzhong; Fan, Haiwei

    2016-11-01

    Two types of three-layered Al/Mg/Al clad sheets were fabricated by hot rolling. The first (sheet A) underwent a single pass with a small rolling reduction of 33% and the second (sheet B) underwent four passes with a large rolling reduction of 71%, and both were subsequently annealed at 200 °C for 1 h. Microstructural examination and tensile tests on the fabricated sheets revealed that 17.8-μm-thick intermetallic compound layers (IMCLs) appeared at AZ31/5052 interfaces in sheet B while none were observed in sheet A. The AZ31 layers in sheets A and B exhibited basal textures with intensities of 15.1 and 9.8, respectively, and only sheet A exhibited tensile twins (TTs) in the AZ31 layer. Recrystallization resulting in grains was preferred near the AZ31/5052 interface and the intersections between TTs. Owing to its larger rolling reduction, more extensive recrystallization was observed in the sheet B component layers than in sheet A. Sheet B exhibited better mechanical properties with a much higher ultimate tensile strength (UTS) than sheet A (230 versus 102 MPa) and a slightly larger elongation (19 versus 17%).This indicates that texture intensities and the extent of recrystallization of component layers have a significant effect upon the mechanical properties of clad sheets.

  17. Interface considerations in Al2O3/NiAl composite

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.

    1993-01-01

    The fiber-matrix interface requirements in an Al2O3/NiAl composite were examined from theoretical considerations. Several factors that influence the interface bonding requirements were analyzed. These include: (1) residual stresses due to fiber-matrix coefficient of thermal expansion (CTE) mismatch; (2) matrix cracking stress at room temperature; (3) fracture toughness at room temperature; (4) load transfer from the matrix to the fiber and ultimate tensile strength at the use temperature; and (5) creep resistance at high temperature. A relatively weak fiber-matrix bond, with an interfacial shear strength of approximately 15-20 MPa, might be sufficient for attaining the desired mechanical properties in the fiber direction at the use temperature. A weak fiber-matrix bond is also beneficial for increasing the fracture toughness of the composite at room temperature. In contrast, a strong fiber-matrix bond is required to withstand some of the residual stresses resulting from the fiber-matrix CTE mismatch, which are not likely to be reduced significantly by interface coatings. A relatively strong bond is also beneficial in increasing the matrix cracking stress at room temperature. Various interface coating options to accommodate the conflicting bonding requirements were reviewed. One viable coating option is to incorporate a thick, ductile interface layer well bonded to both the fiber and the matrix.

  18. 76 FR 78717 - In the Matter of the Designation of Saleh al-Qarawi also known as Saleh Al Qarawi also known as...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-19

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF STATE In the Matter of the Designation of Saleh al-Qarawi also known as Saleh Al Qarawi also known as Saleh Abudullah Saleh Al Qarawi also known as Saleh bin Abdullah al-Qarawi also known as Akhuk al Saghir also known as Fawakeh also known as Mootasem also know...

  19. 75 FR 76771 - In the Matter of the Designation of Fahd Mohammed Ahmed al-Quso, also known as Fahd al-Quso, also...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-09

    ... Matter of the Designation of Fahd Mohammed Ahmed al-Quso, also known as Fahd al-Quso, also known as Abu...-Bara', also known as Abu Hathayfah al-Adani, also known as Fahd Mohammed Ahmed al-Awlaqi, also known as... January 23, 2003, I hereby determine that the individual known as Fahd Mohammed Ahmed al-Quso, also known...

  20. 77 FR 61046 - The Review and Amendment of the Designation of Al-Qa'ida in the Arabian Peninsula, aka Al-Qa'ida...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-05

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE The Review and Amendment of the Designation of Al-Qa'ida in the Arabian Peninsula, aka Al-Qa'ida of Jihad Organization in the Arabian Peninsula, aka Tanzim Qa'idat al-Jihad fi Jazirat al-Arab, aka Al- Qa'ida in Yemen...

  1. Ptosis and bulbar onset: an unusual phenotype of familial ALS?

    PubMed

    De Marchi, Fabiola; Corrado, L; Bersano, E; Sarnelli, M F; Solara, V; D'Alfonso, S; Cantello, R; Mazzini, L

    2017-11-13

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder of upper and lower motor neurons that usually spare the oculomotor nerves. Here, we describe a case of two siblings with a familial bulbar-onset ALS both with ptosis manifested at the onset of the disease.

  2. Lanthanide Al-Ni base Ericsson cycle magnetic refrigerants

    DOEpatents

    Gschneidner, Jr., Karl A.; Takeya, Hiroyuki

    1995-10-31

    A magnetic refrigerant for a magnetic refrigerator using the Ericsson thermodynamic cycle comprises DyAlNi and (Gd.sub.0.54 Er.sub.0.46)AlNi alloys having a relatively constant .DELTA.Tmc over a wide temperature range.

  3. Gaseous modification of MCrAlY coatings

    DOEpatents

    Vance, Steven J.; Goedjen, John G.; Sabol, Stephen M.; Sloan, Kelly M.

    2000-01-01

    The present invention generally describes methods for modifying MCrAlY coatings by using gaseous carburization, gaseous nitriding or gaseous carbonitriding. The modified MCrAlY coatings are useful in thermal barrier coating systems, which may be used in gas turbine engines.

  4. Common ground: stem cell approaches find shared pathways underlying ALS.

    PubMed

    Matus, Soledad; Medinas, Danilo B; Hetz, Claudio

    2014-06-05

    The development of curative therapies for genetically complex diseases such as ALS has been delayed by the lack of relevant disease models. Recent advances using induced-pluripotent-stem-cell-derived motoneurons from patients harboring distinct ALS mutations have recapitulated essential disease features and have identified some common pathways driving disease pathogenesis. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. 75 FR 4270 - Modification of Class E Airspace; Anniston, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 Modification of Class E Airspace; Anniston, AL AGENCY... October 28, 2009 that modifies the Class E airspace at Anniston Metropolitan Airport, Anniston, AL. DATES...

  6. 75 FR 13670 - Amendment of Class E Airspace; Gadsden, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Gadsden, AL AGENCY: Federal... December 29, 2009 that amends Class E airspace at Northeast Alabama Regional, Gadsden, AL. DATES: Effective...

  7. 76 FR 80232 - Establishment of Class E Airspace; Oneonta, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... 14 CFR Part 71 [Docket No. FAA-2011-0744; Airspace Docket No. 11-ASO-33] Establishment of Class E... action establishes Class E Airspace at Oneonta, AL, to accommodate the new Area Navigation (RNAV) Global... establish Class E airspace at Oneonta, AL (76 FR 58728) Docket No. FAA-2011-0744. Interested parties were...

  8. Covalent versus Ionic Bonding in Al-C Clusters.

    PubMed

    Du, Ning; Yang, Huihui; Chen, Hongshan

    2017-05-25

    The low-energy structures of Al n C m (n = 4, 6; m = 1-4) are determined by using the genetic algorithm combined with density functional theory and the QCISD models. The electronic structures and bonding features are analyzed through the density of states (DOS), valence molecular orbitals (MOs), and electron localization function (ELF). The results show that the carbon atoms tend to aggregate and sit at the center of the clusters. The C-C bond lengths in most cases agree with the double C═C bond. Because of the large difference between the electronegativities of carbon and aluminum atoms, almost all of the 3p electrons of Al transfer to C atoms. The 3s orbitals of Al and the 2s2p orbitals of C form bonding and antibonding orbitals; the bonding orbitals correspond to the covalent C-Al bonds, and the antibonding orbitals form lone pair electrons on the outer side of Al atoms. The lone pair electrons form large local dipole moments and enhance the electrostatic interactions between C and Al atoms. Planar geometry and multiconnection are prominent structural patterns in small Al n C m clusters. However, the multiconnection does not correspond to multicenter chemical bonding. There are multicenter bonds, but they are much weaker than the σ C-Al bonds.

  9. The utility of covariances: a response to Ranta et al

    Treesearch

    J.E. Houlahan; K. Cottenie; G.S. Cumming; D.J. Currie; C.S. Findlay; U. Gaedke; P. Legendre; J.J. Magnuson; B.H. McArdle; R.D. Stevens; I.P. Woiwod; S.M. Wondzell

    2008-01-01

    In an earlier publication (Houlahan et al. 2007) we reviewed trends in population covariances within communities across a range of long-term empirical data sets. We used these results to argue that compensatory dynamics are rare in natural communities. Ranta et al. (2008) explored interspecific interactions in a simulated environment and showed that 'negative...

  10. Catalase activity in blood fractions of patients with sporadic ALS.

    PubMed

    Golenia, Aleksandra; Leśkiewicz, Monika; Regulska, Magdalena; Budziszewska, Bogusława; Szczęsny, Ewa; Jagiełła, Jeremiasz; Wnuk, Marcin; Ostrowska, Monika; Lasoń, Władysław; Basta-Kaim, Agnieszka; Słowik, Agnieszka

    2014-08-01

    Oxidative stress may be a key element in pathogenesis of sporadic amyotrophic lateral sclerosis (sALS). Several studies proved that markers of peroxidation of lipids, proteins or nucleic acids are increased in postmortem tissue of sALS patients. However, much less is known about enzymatic antioxidant defense mechanism in sALS. The aim of the study was to assess catalase (CAT) activity that is implicated in the defense against oxidative stress, in three blood fractions, i.e. erythrocytes, plasma and serum of sALS patients and healthy controls. Altogether 46 sALS patients and 54 controls were enrolled in the study. CAT activity was estimated using a commercially available assay kit. CAT activity in erythrocytes of sALS patients was significantly decreased compared to neurologically healthy controls (p=0.04), whereas CAT activity in plasma and serum was similar in both studied groups. CAT activity in erythrocytes, in contrast to other blood fractions is reduced in sALS cases as compared to controls, which may indirectly indicate that antioxidant defense system in erythrocytes is involved in pathogenesis of sALS. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  11. Al-Faruqi's Fundamental Ideas and Philosophy of Education

    ERIC Educational Resources Information Center

    Rahman, Tasnim Abdul; Yusof, Wan Sabri Wan; Rashid, Zuriati Mohd; Amir, Ahmad Nabil

    2015-01-01

    This paper discusses the fundamental ideal and philosophy of education advocated by Ismail Raji al-Faruqi (1921-1986) in realizing the Islamization of knowledge (IOK) project. The concept and perspective of education projected by al-Faruqi was constructed on the worldview of tawhid that reflected the essence and intrinsic philosophy and paradigm…

  12. 78 FR 39023 - ING Investments, LLC, et al.;

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-28

    ... COMMISSION ING Investments, LLC, et al.; Notice of Application June 24, 2013. AGENCY: Securities and Exchange Commission (``Commission''). ACTION: Notice of an application under section 6(c) of the Investment Company... shareholder approval. \\1\\ Portfolio Partners, Inc., et al., Investment Company Act Release Nos. 25558 (Apr. 30...

  13. Irradiation-enhanced reactivity of multilayer Al/Ni nanomaterials.

    PubMed

    Manukyan, Khachatur V; Tan, Wanpeng; deBoer, Richard J; Stech, Edward J; Aprahamian, Ani; Wiescher, Michael; Rouvimov, Sergei; Overdeep, Kyle R; Shuck, Christopher E; Weihs, Timothy P; Mukasyan, Alexander S

    2015-06-03

    We have investigated the effect of accelerated ion beam irradiation on the structure and reactivity of multilayer sputter deposited Al/Ni nanomaterials. Carbon and aluminum ion beams with different charge states and intensities were used to irradiate the multilayer materials. The conditions for the irradiation-assisted self-ignition of the reactive materials and corresponding ignition thresholds for the beam intensities were determined. We discovered that relatively short (40 min or less) ion irradiations enhance the reactivity of the Al/Ni nanomaterials, that is, significantly decrease the thermal ignition temperatures (Tig) and ignition delay times (τig). We also show that irradiation leads to atomic mixing at the Al/Ni interfaces with the formation of an amorphous interlayer, in addition to the nucleation of small (2-3 nm) Al3Ni crystals within the amorphous regions. The amorphous interlayer is thought to enhance the reactivity of the multilayer energetic nanomaterial by increasing the heat of the reaction and by speeding the intermixing of the Ni and the Al. The small Al3Ni crystals may also enhance reactivity by facilitating the growth of this Al-Ni intermetallic phase. In contrast, longer irradiations decrease reactivity with higher ignition temperatures and longer ignition delay times. Such changes are also associated with growth of the Al3Ni intermetallic and decreases in the heat of reaction. Drawing on this data set, we suggest that ion irradiation can be used to fine-tune the structure and reactivity of energetic nanomaterials.

  14. Ayman Al-Zawahiri: The Ideologue of Modern Islamic Militancy

    DTIC Science & Technology

    2004-03-01

    and Midhat Mursi (Weapons and Research) to name a few top echelon members of Al-Qaeda.19 These are all handpicked EIJ members that Al-Zawahiri...cells was taken into consideration, and Yemen, unstable due to the skirmishes between tribes , was looked at as containing a robust Egyptian

  15. The Practical Enactment of Adventure Learning: Where Will You AL@?

    ERIC Educational Resources Information Center

    Miller, Brant G.; Hougham, R. Justin; Eitel, Karla Bradley

    2013-01-01

    The Adventure Learning (AL) approach to designing and implementing learning experiences has great potential for practitioners. This manuscript delineates the practical enactment of AL to support the K-12 community, teacher educators, and residential environmental science program providers in the conceptualization and delivery of their own AL…

  16. Assessing the Incremental Algorithm: A Response to Krahmer et al.

    ERIC Educational Resources Information Center

    van Deemter, Kees; Gatt, Albert; van der Sluis, Ielka; Power, Richard

    2012-01-01

    This response discusses the experiment reported in Krahmer et al.'s Letter to the Editor of "Cognitive Science". We observe that their results do not tell us whether the Incremental Algorithm is better or worse than its competitors, and we speculate about implications for reference in complex domains, and for learning from "normal" (i.e.,…

  17. ATXN2 trinucleotide repeat length correlates with risk of ALS.

    PubMed

    Sproviero, William; Shatunov, Aleksey; Stahl, Daniel; Shoai, Maryam; van Rheenen, Wouter; Jones, Ashley R; Al-Sarraj, Safa; Andersen, Peter M; Bonini, Nancy M; Conforti, Francesca L; Van Damme, Philip; Daoud, Hussein; Del Mar Amador, Maria; Fogh, Isabella; Forzan, Monica; Gaastra, Ben; Gellera, Cinzia; Gitler, Aaron D; Hardy, John; Fratta, Pietro; La Bella, Vincenzo; Le Ber, Isabelle; Van Langenhove, Tim; Lattante, Serena; Lee, Yi-Chung; Malaspina, Andrea; Meininger, Vincent; Millecamps, Stéphanie; Orrell, Richard; Rademakers, Rosa; Robberecht, Wim; Rouleau, Guy; Ross, Owen A; Salachas, Francois; Sidle, Katie; Smith, Bradley N; Soong, Bing-Wen; Sorarù, Gianni; Stevanin, Giovanni; Kabashi, Edor; Troakes, Claire; van Broeckhoven, Christine; Veldink, Jan H; van den Berg, Leonard H; Shaw, Christopher E; Powell, John F; Al-Chalabi, Ammar

    2017-03-01

    We investigated a CAG trinucleotide repeat expansion in the ATXN2 gene in amyotrophic lateral sclerosis (ALS). Two new case-control studies, a British dataset of 1474 ALS cases and 567 controls, and a Dutch dataset of 1328 ALS cases and 691 controls were analyzed. In addition, to increase power, we systematically searched PubMed for case-control studies published after 1 August 2010 that investigated the association between ATXN2 intermediate repeats and ALS. We conducted a meta-analysis of the new and existing studies for the relative risks of ATXN2 intermediate repeat alleles of between 24 and 34 CAG trinucleotide repeats and ALS. There was an overall increased risk of ALS for those carrying intermediate sized trinucleotide repeat alleles (odds ratio 3.06 [95% confidence interval 2.37-3.94]; p = 6 × 10 -18 ), with an exponential relationship between repeat length and ALS risk for alleles of 29-32 repeats (R 2  = 0.91, p = 0.0002). No relationship was seen for repeat length and age of onset or survival. In contrast to trinucleotide repeat diseases, intermediate ATXN2 trinucleotide repeat expansion in ALS does not predict age of onset but does predict disease risk. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  18. Experience matters: neurologists' perspectives on ALS patients' well-being.

    PubMed

    Aho-Özhan, Helena E A; Böhm, Sarah; Keller, Jürgen; Dorst, Johannes; Uttner, Ingo; Ludolph, Albert C; Lulé, Dorothée

    2017-04-01

    Despite the fatal outcome and progressive loss of physical functioning in amyotrophic lateral sclerosis (ALS), many patients maintain contentment in life. It has been shown that non-professionals tend to underestimate the well-being of patients with ALS, but professionals' perspective is yet to be studied. In total, 105 neurologists with varying degrees of experience with ALS were included in an anonymous survey. They were asked to estimate the quality of life and depressiveness of ALS patients with artificial ventilation and nutrition. Physicians' estimations were compared with previously reported subjective ratings of ALS patients with life-prolonging measures. Neurologists with significant experience on ALS and palliative care were able to accurately estimate depressiveness and quality of life of ALS patients with life-prolonging measures. Less experienced neurologists' estimation differed more from patients' reports. Of all life-prolonging measures neurologists regarded invasive ventilation as the measure associated with lowest quality of life and highest depressiveness of the patients. Experienced neurologists as well as neurologists with experience in palliative care are able to better empathize with patients with a fatal illness such as ALS and support important decision processes.

  19. Oxidation behavior of FeAl+Hf,Zr,B

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Doychak, Joseph; Gaydosh, Darrell J.

    1989-01-01

    The oxidation behavior of Fe-40Al-1Hf, Fe-40Al-1Hf-0.4B, and Fe-40Al-0.1Zr-0.4B (at. percent) alloys was characterized after 900, 1000, and 100 C exposures. Isothermal tests revealed parabolic kinetics after a period of transitional theta-alumina scale growth. The parabolic growth rates for the subsequent alpha-alumina scales were about five times higher than those for NiAl+0.1Zr alloys. The isothermally grown scales showed a propensity toward massive scale spallation due to both extensive rumpling from growth stresses and to an inner layer of Hf02. Cyclic oxidation for 200 1-hr cycles produced little degradation at 900 or 1000 C, but caused significant spallation at 1100 C in the form of small segments of the outer scale. The major difference in the cyclic oxidation of the three FeAl alloys was increased initial spallation for FeAl+Zr,B. Although these FeAl alloys showed many similarities to NiAl alloys, they were generally less oxidation resistant. It is believed that this resulted from nonoptimal levels of dopants and larger thermal expansion mismatch stresses.

  20. Oxidation behavior of FeAl+Hf,Zr,B

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Doychak, Joseph

    1988-01-01

    The oxidation behavior of Fe-40Al-1Hf, Fe-40Al-1Hf-0.4B, and Fe-40Al-0.1Zr-0.4B (at. percent) alloys was characterized after 900, 1000, and 100 C exposures. Isothermal tests revealed parabolic kinetics after a period of transitional theta-alumina scale growth. The parabolic growth rates for the subsequent alpha-alumina scales were about five times higher than those for NiAl+0.1Zr alloys. The isothermally grown scales showed a propensity toward massive scale spallation due to both extensive rumpling from growth stresses and to an inner layer of HfO2. Cyclic oxidation for 200 1-hr cycles produced little degradation at 900 or 1000 C, but caused significant spallation at 1100 C in the form of small segments of the outer scale. The major difference in the cyclic oxidation of the three FeAl alloys was increased initial spallation for FeAl+Zr,B. Although these FeAl alloys showed many similarities to NiAl alloys, they were generally less oxidation resistant. It is believed that this resulted from nonoptimal levels of dopants and larger thermal expansion mismatch stresses.

  1. Lanthanide Al-Ni base Ericsson cycle magnetic refrigerants

    DOEpatents

    Gschneidner, K.A. Jr.; Takeya, Hiroyuki

    1995-10-31

    A magnetic refrigerant for a magnetic refrigerator using the Ericsson thermodynamic cycle comprises DyAlNi and (Gd{sub 0.54}Er{sub 0.46})AlNi alloys having a relatively constant {Delta}Tmc over a wide temperature range. 16 figs.

  2. Microarray analysis of peripheral blood lymphocytes from ALS patients and the SAFE detection of the KEGG ALS pathway

    PubMed Central

    2011-01-01

    Background Sporadic amyotrophic lateral sclerosis (sALS) is a motor neuron disease with poorly understood etiology. Results of gene expression profiling studies of whole blood from ALS patients have not been validated and are difficult to relate to ALS pathogenesis because gene expression profiles depend on the relative abundance of the different cell types present in whole blood. We conducted microarray analyses using Agilent Human Whole Genome 4 × 44k Arrays on a more homogeneous cell population, namely purified peripheral blood lymphocytes (PBLs), from ALS patients and healthy controls to identify molecular signatures possibly relevant to ALS pathogenesis. Methods Differentially expressed genes were determined by LIMMA (Linear Models for MicroArray) and SAM (Significance Analysis of Microarrays) analyses. The SAFE (Significance Analysis of Function and Expression) procedure was used to identify molecular pathway perturbations. Proteasome inhibition assays were conducted on cultured peripheral blood mononuclear cells (PBMCs) from ALS patients to confirm alteration of the Ubiquitin/Proteasome System (UPS). Results For the first time, using SAFE in a global gene ontology analysis (gene set size 5-100), we show significant perturbation of the KEGG (Kyoto Encyclopedia of Genes and Genomes) ALS pathway of motor neuron degeneration in PBLs from ALS patients. This was the only KEGG disease pathway significantly upregulated among 25, and contributing genes, including SOD1, represented 54% of the encoded proteins or protein complexes of the KEGG ALS pathway. Further SAFE analysis, including gene set sizes >100, showed that only neurodegenerative diseases (4 out of 34 disease pathways) including ALS were significantly upregulated. Changes in UBR2 expression correlated inversely with time since onset of disease and directly with ALSFRS-R, implying that UBR2 was increased early in the course of ALS. Cultured PBMCs from ALS patients accumulated more ubiquitinated proteins

  3. ER Dysfunction and Protein Folding Stress in ALS

    PubMed Central

    Matus, Soledad; Valenzuela, Vicente; Medinas, Danilo B.; Hetz, Claudio

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is the most frequent paralytic disease in adults. Most ALS cases are considered sporadic with no clear genetic component. The disruption of protein homeostasis due to chronic stress responses at the endoplasmic reticulum (ER) and the accumulation of abnormal protein inclusions are extensively described in ALS mouse models and patient-derived tissue. Recent studies using pharmacological and genetic manipulation of the unfolded protein response (UPR), an adaptive reaction against ER stress, have demonstrated a complex involvement of the pathway in experimental models of ALS. In addition, quantitative changes in ER stress-responsive chaperones in body fluids have been proposed as possible biomarkers to monitor the disease progression. Here we review most recent advances attributing a causal role of ER stress in ALS. PMID:24324498

  4. Room temperature luminescence and ferromagnetism of AlN:Fe

    SciTech Connect

    Li, H. E-mail: wjwang@aphy.iphy.ac.cn; Cai, G. M.; Wang, W. J. E-mail: wjwang@aphy.iphy.ac.cn

    2016-06-15

    AlN:Fe polycrystalline powders were synthesized by a modified solid state reaction (MSSR) method. Powder X-ray diffraction and transmission electron microscopy results reveal the single phase nature of the doped samples. In the doped AlN samples, Fe is in Fe{sup 2+} state. Room temperature ferromagnetic behavior is observed in AlN:Fe samples. Two photoluminescence peaks located at about 592 nm (2.09 eV) and 598 nm (2.07 eV) are observed in AlN:Fe samples. Our results suggest that AlN:Fe is a potential material for applications in spintronics and high power laser devices.

  5. Covalent functionalization of AlN nanotubes with acetylene

    NASA Astrophysics Data System (ADS)

    Baei, Mohammad T.; Ahmadi Peyghan, Ali; Bagheri, Zargham

    2013-01-01

    Covalent functionalization of a zigzag AlN nanotube (AlNNT) with acetylene molecule has been investigated using density functional theory in terms of energetic, geometry and electronic properties. The obtained results show that the acetylene preferably tends to [2+2] addition on Al-N bonds of the tube surface releasing energies in the range of 1.02 to 1.10 eV along with a charge transfer from the tube to the acetylene. We have found that HOMO-LUMO gap of AlNNT has not changed significantly upon the functionalization and, its global hardness and electrophilicity are slightly decreased. Also, it has been revealed that the field electron emission from the AlNNT surface may be improved upon the adsorption of acetylene due to decrease of work function ascribed to the charge transfer from the tube to the acetylene.

  6. Physical and mechanical metallurgy of NiAl

    NASA Technical Reports Server (NTRS)

    Noebe, Ronald D.; Bowman, Randy R.; Nathal, Michael V.

    1994-01-01

    Considerable research has been performed on NiAl over the last decade, with an exponential increase in effort occurring over the last few years. This is due to interest in this material for electronic, catalytic, coating and especially high-temperature structural applications. This report uses this wealth of new information to develop a complete description of the properties and processing of NiAl and NiAl-based materials. Emphasis is placed on the controlling fracture and deformation mechanisms of single and polycrystalline NiAl and its alloys over the entire range of temperatures for which data are available. Creep, fatigue, and environmental resistance of this material are discussed. In addition, issues surrounding alloy design, development of NiAl-based composites, and materials processing are addressed.

  7. Telomerase expression in amyotrophic lateral sclerosis (ALS) patients.

    PubMed

    De Felice, Bruna; Annunziata, Anna; Fiorentino, Giuseppe; Manfellotto, Francesco; D'Alessandro, Raffaella; Marino, Rita; Borra, Marco; Biffali, Elio

    2014-10-01

    Telomerase and telomeric complex have been linked to a variety of disease states related to neurological dysfunction. In amyotrophic lateral sclerosis (ALS) patients, telomerase activity, as human telomerase reverse transcriptase (hTERT) expression, has not been characterized yet. Here, for the first time, we characterized telomerase and related pathway in blood sample and spinal cord from ALS patients compared with healthy controls. We found that hTERT expression level was significantly lower in ALS patients and was correlated either to p53 mRNA expression or p21 expression, pointing out the hypothesis that telomerase inhibition could be a pathogenetic contributor to neurodegeneration in ALS. As a consequence of the reduced telomerase activity, we identified shorter telomeres in leukocytes from sporadic ALS patients compared with healthy control group.

  8. Slow Orbit Feedback at the ALS Using Matlab

    SciTech Connect

    Portmann, G.

    1999-03-25

    The third generation Advanced Light Source (ALS) produces extremely bright and finely focused photon beams using undulatory, wigglers, and bend magnets. In order to position the photon beams accurately, a slow global orbit feedback system has been developed. The dominant causes of orbit motion at the ALS are temperature variation and insertion device motion. This type of motion can be removed using slow global orbit feedback with a data rate of a few Hertz. The remaining orbit motion in the ALS is only 1-3 micron rms. Slow orbit feedback does not require high computational throughput. At the ALS, the globalmore » orbit feedback algorithm, based on the singular valued decomposition method, is coded in MATLAB and runs on a control room workstation. Using the MATLAB environment to develop, test, and run the storage ring control algorithms has proven to be a fast and efficient way to operate the ALS.« less

  9. A Fruitful Endeavor: Modeling ALS in the Fruit Fly

    PubMed Central

    Casci, Ian; Pandey, Udai Bhan

    2014-01-01

    For over a century Drosophila melanogaster, commonly known as the fruit fly, has been instrumental in genetics research and disease modeling. In more recent years, it has been a powerful tool for modeling and studying neurodegenerative diseases, including the devastating and fatal amyotrophic lateral sclerosis (ALS). The success of this model organism in ALS research comes from the availability of tools to manipulate gene/protein expression in a number of desired cell-types, and the subsequent recapitulation of cellular and molecular phenotypic features of the disease. Several Drosophila models have now been developed for studying the roles of ALS-associated genes in disease pathogenesis that allowed us to understand the molecular pathways that lead to motor neuron degeneration in ALS patients. Our primary goal in this review is to highlight the lessons we have learned using Drosophila models pertaining to ALS research. PMID:25289585

  10. Fabric cutting application of FeAl-based alloys

    SciTech Connect

    Sikka, V.K.; Blue, C.A.; Sklad, S.P.; Deevi, S.C.; Shih, H.R.

    1998-11-01

    Four intermetallic-based alloys were evaluated for cutting blade applications. These alloys included Fe{sub 3}Al-based (FAS-II and FA-129), FeAl-based (PM-60), and Ni{sub 3}Al-based (IC-50). These alloys were of interest because of their much higher work-hardening rates than the conventionally used carbon and stainless steels. The FeAl-based PM-60 alloy was of further interest because of its hardening possibility through retention of vacancies. The vacancy retention treatment is much simpler than the heat treatments used for hardening of steel blades. Blades of four intermetallic alloys and commercially used M2 tool steel blades were evaluated under identical conditions to cut two-ply heavy paper. Comparative results under identical conditions revealed that the FeAl-based alloy PM-60 outperformed the other intermetallic alloys and was equal to or somewhat better than the commercially used M2 tool steel.

  11. Evolution of Voids in Mg/Al Diffusion Bonding Process

    NASA Astrophysics Data System (ADS)

    Long, Luping; Liu, Wensheng; Ma, Yunzhu; Wu, Lei; Tang, Siwei

    2017-10-01

    The closure process of voids was very crucial for diffusion bonding, voids behaviors in Mg/Al bonding process were investigated, and the control mechanisms of diffusion at different predominant process parameters were discussed in this paper. Finite element simulation was utilized to investigate the influence of thermal residual stresses on the appearance of secondary voids. The results showed that: the dominant mechanism of void closure was plastic deformation in the initial stage of Mg/Al diffusion bonding. Numerical results indicated that secondary voids could be easily generated in the regions where tensile residual stress gradient achieves the maximum, corresponding to area that Al3Mg2 layer at the nearby Al/Al3Mg2 interface, the segregation of voids deteriorated the performances of the bonded joints.

  12. Synthesis of Al2Ca Dispersoids by Powder Metallurgy Using a Mg–Al Alloy and CaO Particles

    PubMed Central

    Fujita, Junji; Umeda, Junko; Kondoh, Katsuyoshi

    2017-01-01

    The elemental mixture of Mg-6 wt %Al-1 wt %Zn-0.3 wt %Mn (AZ61B) alloy powder and CaO particles was consolidated by an equal-channel angular bulk mechanical alloying (ECABMA) process to form a composite precursor. Subsequently, the precursor was subjected to a heat treatment to synthesize fine Al2Ca particles via a solid-state reaction between the Mg–Al matrix and CaO additives. Scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and electron probe micro-analysis on the precursor indicated that 4.7-at % Al atoms formed a supersaturated solid solution in the α-Mg matrix. Transmission electron microscopy-EDS and X-ray diffraction analyses on the AZ61B composite precursor with 10-vol % CaO particles obtained by heat treatment confirmed that CaO additives were thermally decomposed in the Mg–Al alloy, and the solid-soluted Ca atoms diffused along the α-Mg grain boundaries. Al atoms also diffused to the grain boundaries because of attraction to the Ca atoms resulting from a strong reactivity between Al and Ca. As a result, needle-like (Mg,Al)2Ca intermetallics were formed as intermediate precipitates in the initial reaction stage during the heat treatment. Finally, the precipitates were transformed into spherical Al2Ca particles by the substitution of Al atoms for Mg atoms in (Mg,Al)2Ca after a long heat treatment. PMID:28773074

  13. Magnetically induced current densities in Al4 (2-) and Al4 (4-) species studied at the coupled-cluster level.

    PubMed

    Lin, Ying-Chan; Jusélius, Jonas; Sundholm, Dage; Gauss, Jürgen

    2005-06-01

    Magnetically induced current densities in the four-membered rings of Al4(2-) and Al4(4-) species have been calculated at the coupled-cluster singles and doubles (CCSD) level by applying the recently developed gauge-including magnetically induced current (GIMIC) method. The strength of the ring-current susceptibilities were obtained by numerical integration of the current densities passing through a cross section perpendicular to the Al4 ring. The GIMIC calculations support the earlier notion that Al4 (2-) with formally two pi electrons sustains a net diatropic ring current. The diatropic contribution to the ring-current susceptibility is carried by the electrons in both the sigma (16.7 nAT) and the pi (11.3 nAT) orbitals. The induced ring current in the Al4 (4-) compounds, with four pi electrons, consists of about equally strong diatropic sigma and paratropic pi currents of about 14 and -17 nAT, respectively. The net current susceptibilities obtained for Al4Li-, Al4Li2, Al4Li3(-), and Al4Li4 at the CCSD level using a triple-zeta basis set augmented with polarization functions are 28.1, 28.1, -5.9, and -3.1 nAT, respectively. The corresponding diatropic (paratropic) contributions to the ring-current susceptibilities are 32.4 (0.0), 36.7 (0.0), 18.9 (-19.9), and 18.6 (-16.8) nAT, respectively. For the Al4(2-) and Al4(4-) species, the net currents circling each Li+ cation is estimated to 4.3 and 2.4 nAT, respectively.

  14. Microbial Bioreactor Development in the ALS NSCORT

    NASA Astrophysics Data System (ADS)

    Mitchell, Cary; Whitaker, Dawn; Banks, M. Katherine; Heber, Albert J.; Turco, Ronald F.; Nies, Loring F.; Alleman, James E.; Sharvelle, Sybil E.; Li, Congna; Heller, Megan

    The NASA Specialized Center of Research and Training in Advanced Life Support (the ALS NSCORT), a partnership of Alabama A & M, Howard, and Purdue Universities, was established by NASA in 2002 to develop technologies that will reduce the Equivalent System Mass (ESM) of regenerative processes within future space life-support systems. A key focus area of NSCORT research has been the development of efficient microbial bioreactors for treatment of human, crop, and food-process wastes while enabling resource recovery. The approach emphasizes optimizing the energy-saving advantages of hydrolytic enzymes for biomass degradation, with focus on treatment of solid wastes including crop residue, paper, food, and human metabolic wastes, treatment of greywater, cabin air, off-gases from other treatment systems, and habitat condensate. This summary includes important findings from those projects, status of technology development, and recommendations for next steps. The Plant-based Anaerobic-Aerobic Bioreactor-Linked Operation (PAABLO) system was developed to reduce crop residue while generating energy and/or food. Plant residues initially were added directly to the bioreactor, and recalcitrant residue was used as a substrate for growing plants or mushrooms. Subsequently, crop residue was first pretreated with fungi to hydrolyze polymers recalcitrant to bacteria, and leachate from the fungal beds was directed to the anaerobic digester. Exoenzymes from the fungi pre-soften fibrous plant materials, improving recovery of materials that are more easily biodegraded to methane that can be used for energy reclamation. An Autothermal Thermophilic Aerobic Digestion (ATAD) system was developed for biodegradable solid wastes. Objectives were to increase water and nutrient recovery, reduce waste volume, and inactivate pathogens. Operational parameters of the reactor were optimized for degradation and resource recovery while minimizing system requirements and footprint. The start-up behavior

  15. Dynamics of Agglutinin-Like Sequence (ALS) Protein Localization on the Surface of Candida Albicans

    ERIC Educational Resources Information Center

    Coleman, David Andrew

    2009-01-01

    The ALS gene family encodes large cell-surface glycoproteins associated with "C. albicans" pathogenesis. Als proteins are thought to act as adhesin molecules binding to host tissues. Wide variation in expression levels among the ALS genes exists and is related to cell morphology and environmental conditions. "ALS1," "ALS3," and "ALS4" are three of…

  16. Effect of oxygen on active Al concentration in ZnO:Al thin films made by PLD

    NASA Astrophysics Data System (ADS)

    Kodu, M.; Arroval, T.; Avarmaa, T.; Jaaniso, R.; Kink, I.; Leinberg, S.; Savi, K.; Timusk, M.

    2014-11-01

    Al doped ZnO is used as a material for transparent conductive electrodes in solar energy and display screen applications, as well as semiconducting material in electronic and photonic devices. For effective use it is essential to control the electrical and optical properties of ZnO:Al thin films. In order to investigate the influence of oxygen environment on effective Al solubility and intrinsic defects introduced at high doping levels during the film growth, ZnO:Al thin films were deposited in vacuum and oxygen background by pulsed laser deposition method. Films were doped with varying Al concentrations by using targets with Al doping levels of 1-10 at%. In vacuum, substantially increased free electron concentrations were observed for all Al doping levels, which indicates that the formation of acceptor-type defects, acting as electron killer centers, was largely suppressed during the growth in oxygen-poor conditions. The dependence of carrier mobility from Al concentration was also greatly influenced by oxygen conditions during the film growth, suggesting that ionized impurity concentrations in the films deposited in vacuum and oxygen background were significantly different. The results were interpreted in the context of intrinsic acceptor-type defects VZn (zinc vacancy), which concentration is strongly modified by the presence of oxygen during the film deposition. These vacancies are assumed to influence free electron concentration and electron mobility by acting as deep electron acceptors and charged electron scattering centers (VZn2-).

  17. Accelerator mass spectrometry of 26Al at 6 MV using AlO- ions and a gas-filled magnet

    NASA Astrophysics Data System (ADS)

    Miltenberger, Klaus-Ulrich; Müller, Arnold Milenko; Suter, Martin; Synal, Hans-Arno; Vockenhuber, Christof

    2017-09-01

    For accelerator mass spectrometry (AMS) measurements of 26Al the use of AlO- ions holds considerable promise given their ionization yield which is about an order of magnitude higher compared to the commonly used Al- ions. However, the strong isobaric interference introduced by 26MgO- ions must be reduced before the identification in a gas ionization chamber (GIC). At the ETH Zurich 6 MV EN-TANDEM accelerator the foil degrader method as well as the gas-filled magnet (GFM) method were systematically investigated with respect to suppression of 26Mg and acceptance of 26Al. Additionally a new, large-acceptance GIC was designed to capture as large a fraction of the broad beams as possible. The GFM method achieves a 26Mg suppression factor of 103 and an acceptance of 26Al of > 50 % and therefore provides a significant advantage over the degrader foil method (sFoil (26Mg) ≈ 3 ·102,τFoil (26Al) ≈ 30 %). In combination with the 26Mg separation of 104 in the GIC it is now possible to measure samples with a Mg content in the ppm range down to 26Al/27Al ≈10-14 with an overall efficiency that is approximately 5 × improved with respect to the previous TANDEM setup.

  18. Influence of impact speed on water droplet erosion of TiAl compared with Ti6Al4V

    PubMed Central

    Mahdipoor, M.S.; Kirols, H.S.; Kevorkov, D.; Jedrzejowski, P.; Medraj, M.

    2015-01-01

    Water Droplet Erosion (WDE) as a material degradation phenomenon has been a concern in power generation industries for decades. Steam turbine blades and the compressor blades of gas turbines that use water injection usually suffer from WDE. The present work focuses on studying erosion resistance of TiAl as a potential alloy for turbine blades compared to Ti6Al4V, a frequently used blade alloy. Their erosion behaviour is investigated at different droplet impact speeds to determine the relation between erosion performance and impact speed. It is found that the relationship is governed by a power law equation, ER ~ Vn, where the speed exponent is 7–9 for Ti6Al4V and 11–13 for TiAl. There is a contrast between the observed speed exponent in this work and the ones reported in the literature for Ti6Al4V. It is attributed to the different erosion setups and impingement conditions such as different droplet sizes. To verify this, the erosion experiments were performed at two different droplet sizes, 464 and 603 μm. TiAl showed superior erosion resistance in all erosion conditions; however, its erosion performance exhibits higher sensitivity to the impact speed compared to Ti6Al4V. It means that aggressive erosion conditions decrease the WDE resistance superiority of TiAl. PMID:26391370

  19. Interface traps at Al2O3/InAlN/GaN MOS-HEMT -on- 200 mm Si

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Remesh, Nayana; Dolmanan, S. B.; Tripathy, S.; Raghavan, S.; Muralidharan, R.; Nath, Digbijoy N.

    2017-11-01

    We report on the characterization of the interfaces of Al2O3/InAlN/GaN HEMT structure grown on 200 mm diameter silicon using conductance dispersion technique. Irreversible threshold voltage (VTH) shift of up to +∼2.5 V was observed due to the gate stress induced activation of acceptor states. Further, frequency dependent VTH shift during capacitance voltage measurements were also recorded due to the presence of slow traps at InAlN/GaN interface. The conductance dispersion indicated the presence of acceptor traps of the order of ∼4 × 1012 to 7 × 1013 cm-2 eV-1 with a time constant of ∼10 to 350 μs at the InAlN/GaN interface. Trap density at the Al2O3/InAlN was found to be in similar range but with a time constant of ∼2 μs. The presence of high density of traps at InAlN/GaN interface is attributed to the unavoidable growth interruption before the start of InAlN growth.

  20. Searching for consensus in molt terminology 11 years after Howell et al.'s "first basic problem"

    Treesearch

    Jared D. Wolfe; Erik I. Johnson; Ryan S. Terrill

    2014-01-01

    Howell et al. (2003) published an innovative augmentation to terminology proposed by Humphrey and Parkes (1959) that classified bird molt on the basis of perceived evolutionary relationships. Despite apparent universal applicability, Howell et al.’s (2003) proposed terminological changes were met with criticism that cited a failure to verify the evolutionary...

  1. 76 FR 5439 - United States, et al. v. Comcast Corp., et al.; Proposed Final Judgment and Competitive Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    ... From the Federal Register Online via the Government Publishing Office ] Vol. 76 Monday, No. 20 January 31, 2011 Part III Department of Justice Antitrust Division United States, et al. v. Comcast Corp., et al.; Proposed Final Judgment and Competitive Impact Statement; Notice #0;#0;Federal Register / Vol. 76 , No. 20 / Monday, January 31, 2011 /...

  2. ALS-linked mutant SOD1 proteins promote Aβ aggregates in ALS through direct interaction with Aβ.

    PubMed

    Jang, Ja-Young; Cho, Hyungmin; Park, Hye-Yoon; Rhim, Hyangshuk; Kang, Seongman

    2017-11-04

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive degeneration of motor neurons. Aggregation of ALS-linked mutant Cu/Zn superoxide dismutase (SOD1) is a hallmark of a subset of familial ALS (fALS). Recently, intracellular amyloid-β (Aβ) is detected in motor neurons of both sporadic and familial ALS. We have previously shown that intracellular Aβ specifically interacts with G93A, an ALS-linked SOD1 mutant. However, little is known about the pathological and biological effect of this interaction in neurons. In this study, we have demonstrated that the Aβ-binding region is exposed on the SOD1 surface through the conformational changes due to misfolding of SOD1. Interestingly, we found that the intracellular aggregation of Aβ is enhanced through the direct interaction of Aβ with the Aβ-binding region exposed to misfolded SOD1. Ultimately, increased Aβ aggregation by this interaction promotes neuronal cell death. Consistent with this result, Aβ aggregates was three-fold higher in the brains of G93A transgenic mice than those of non Tg. Our study provides the first direct evidence that Aβ, an AD-linked factor, is associated to the pathogenesis of ALS and provides molecular clues to understand common aggregation mechanisms in the pathogenesis of neurodegenerative diseases. Furthermore, it will provide new insights into the development of therapeutic approaches for ALS. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Spectroscopic evidence of Cu-Al interactions in Cu-Zn-Al mixed oxide catalysts used in CO hydrogenation

    SciTech Connect

    Figueiredo, R.T.; Martinez-Arias, A.; Granados, M.L.

    1998-08-15

    Three different Cu-Zn-Al catalysts (Cu:Zn:Al atomic ratio 60:38:2) were prepared by coprecipitation of the three metals (from their nitrate salts) either by separately precipitating each metal (Cu + Zn + Al), two metals (Cu and Zn coprecipitated + Al) before mixing together, or by precipitating the three of them together. XPS analysis detected a remarkably high Al enrichment at the surface of all calcined or reduced samples, along with a binding energy of the Cu 2p{sub 3/2} core level peak assigned to Cu{sup 2+} in CuAl{sub 2}O{sub 4}-like environment in the calcined state. ESR spectra of calcined samples showed signalsmore » attributed to surface Cu{sup 2+} species with Al entities in their surroundings for samples in which Cu and Zn are coprecipitated and aged together. The higher Cu dispersion observed after reduction for these catalysts is attributed to the development of such interactions at the surface of Al-containing calcined samples.« less

  4. Hydrogen generation using the corrosion of Al-Sn and Al-Si alloys in an alkaline solution

    NASA Astrophysics Data System (ADS)

    Yoo, Jeong-Hyun; Yun, Kwi-Sub; Kalubarme, Ramchandra S.; Park, Choong-Nyeon; Park, Chan-Jin

    2014-07-01

    We investigated the effects of adding Sn and Si to Al alloys on the corrosion of the alloys and the generation of hydrogen from an alkaline solution using the alloys. With increasing Sn content of up to 20 wt% in the Al-Sn alloy, the volume fraction of the Sn phase as a cathodic site at grain boundaries increased, and consequently, the hydrogen generation rate from an alkaline solution by the alloy also increased. In addition, the quenched Al-Sn alloys had smaller grain sizes compared to the furnace-cooled alloys, and accordingly, exhibited a slightly higher hydrogen generation rate. A galvanic cell was formed between the Al grain and the Sn phase of the grain boundary, and accordingly, intergranular type corrosion was observed on the Al-Sn alloys. Compared with the Al-Sn alloys, a more uniform type corrosion was observed on the Al-Si alloys because the nobler Si was uniformly distributed in the eutectic region formed between the primary Al grains. The hydrogen generation rate increased with an increasing Si content up to 10 wt% and was greater for the furnace-cooled samples than that for the quenched samples due to the more clearly formed eutectic structure.

  5. 75 FR 37651 - United States et al. v. Ticketmaster Entertainment, Inc. et al.; Public Comments and Response on...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-29

    ... From the Federal Register Online via the Government Publishing Office ] Part IV Department of Justice Antitrust Division United States et al. v. Ticketmaster Entertainment, Inc. et al.; Public Comments and Response on Proposed Final Judgment; Notice #0;#0;Federal Register / Vol. 75, No. 124 / Tuesday, June 29, 2010 / Notices#0;#0; ] DEPARTMENT OF JUSTIC...

  6. Influence of impact speed on water droplet erosion of TiAl compared with Ti6Al4V

    NASA Astrophysics Data System (ADS)

    Mahdipoor, M. S.; Kirols, H. S.; Kevorkov, D.; Jedrzejowski, P.; Medraj, M.

    2015-09-01

    Water Droplet Erosion (WDE) as a material degradation phenomenon has been a concern in power generation industries for decades. Steam turbine blades and the compressor blades of gas turbines that use water injection usually suffer from WDE. The present work focuses on studying erosion resistance of TiAl as a potential alloy for turbine blades compared to Ti6Al4V, a frequently used blade alloy. Their erosion behaviour is investigated at different droplet impact speeds to determine the relation between erosion performance and impact speed. It is found that the relationship is governed by a power law equation, ER ~ Vn, where the speed exponent is 7-9 for Ti6Al4V and 11-13 for TiAl. There is a contrast between the observed speed exponent in this work and the ones reported in the literature for Ti6Al4V. It is attributed to the different erosion setups and impingement conditions such as different droplet sizes. To verify this, the erosion experiments were performed at two different droplet sizes, 464 and 603 μm. TiAl showed superior erosion resistance in all erosion conditions; however, its erosion performance exhibits higher sensitivity to the impact speed compared to Ti6Al4V. It means that aggressive erosion conditions decrease the WDE resistance superiority of TiAl.

  7. Influence of impact speed on water droplet erosion of TiAl compared with Ti6Al4V.

    PubMed

    Mahdipoor, M S; Kirols, H S; Kevorkov, D; Jedrzejowski, P; Medraj, M

    2015-09-22

    Water Droplet Erosion (WDE) as a material degradation phenomenon has been a concern in power generation industries for decades. Steam turbine blades and the compressor blades of gas turbines that use water injection usually suffer from WDE. The present work focuses on studying erosion resistance of TiAl as a potential alloy for turbine blades compared to Ti6Al4V, a frequently used blade alloy. Their erosion behaviour is investigated at different droplet impact speeds to determine the relation between erosion performance and impact speed. It is found that the relationship is governed by a power law equation, ER ~ V(n), where the speed exponent is 7-9 for Ti6Al4V and 11-13 for TiAl. There is a contrast between the observed speed exponent in this work and the ones reported in the literature for Ti6Al4V. It is attributed to the different erosion setups and impingement conditions such as different droplet sizes. To verify this, the erosion experiments were performed at two different droplet sizes, 464 and 603 μm. TiAl showed superior erosion resistance in all erosion conditions; however, its erosion performance exhibits higher sensitivity to the impact speed compared to Ti6Al4V. It means that aggressive erosion conditions decrease the WDE resistance superiority of TiAl.

  8. The in vitro biocompatibility and macrophage phagocytosis of Mg17Al12 phase in Mg-Al-Zn alloys.

    PubMed

    Liu, Chen; He, Peng; Wan, Peng; Li, Mei; Wang, Kehong; Tan, Lili; Zhang, Yu; Yang, Ke

    2015-07-01

    Mg alloys are gaining interest for applications as biodegradable medical implant, including Mg-Al-Zn series alloys with good combination of mechanical properties and reasonable corrosion resistance. However, whether the existence of second phase particles in the alloys exerts influence on the biocompatibility is still not clear. A deeper understanding of how the particles regulate specific biological responses is becoming a crucial requirement for their subsequent biomedical application. In this work, the in vitro biocompatibility of Mg17Al12 as a common second phase in biodegradable Mg-Al-Zn alloys was investigated via hemolysis, cytotoxicity, cell proliferation, and cell adhesion tests. Moreover, osteogenic differentiation was evaluated by the extracellular matrix mineralization assay. The Mg17Al12 particles were also prepared to simulate the real situation of second phase in the in vivo environment in order to estimate the cellular response in macrophages to the Mg17Al12 particles. The experimental results indicated that no hemolysis was found and an excellent cytocompatibility was also proved for the Mg17Al12 second phase when co-cultured with L929 cells, MC3T3-E1 cells and BMSCs. Macrophage phagocytosis co-culture test revealed that Mg17Al12 particles exerted no harmful effect on RAW264.7 macrophages and could be phagocytized by the RAW264.7 cells. Furthermore, the possible inflammatory reaction and metabolic way for Mg17Al12 phase were also discussed in detail. © 2014 Wiley Periodicals, Inc.

  9. The mechanism of Al donor defects in (Zn, Co)O:Al: a view from resonant x-ray spectroscopies

    NASA Astrophysics Data System (ADS)

    Zhou, K. J.; Tezuka, Y.; Cui, M. Q.; Zhao, J.; Liu, X. C.; Chen, Z. Z.; Wu, Z. Y.

    2009-12-01

    We studied the effect of Al doping in Zn0.94Co0.05Al0.01O nano-powders from the electronic structure point of view by applying x-ray absorption spectroscopy and resonant inelastic x-ray scattering at the oxygen K- and Co L-edges. The intensity of the pre-edge structure of the O-K XAS spectra is enhanced following the introduction of the Al defect. Multiple scattering calculations demonstrate it can be accounted for by the gain of the hybridization strength between O 2p and Al 3p (and/or Co 3d) states. The consensus on the hybridization strength is reached by combining Co-L XAS and RIXS investigations and multiplet calculations. It reveals different spatial substitutions of Al doping can alter the number of shared oxygen atoms between the Co and Al tetrahedrons. These shared ligands are responsible for the Al 3p and Co 3d state hybridization strength as well as the ferromagnetism of the ground state. The magnetic difference is better understood to be governed by various shared oxygen atoms rather than the distance between the Al defect and Co impurities.

  10. An AlN/Al 0.85Ga 0.15N high electron mobility transistor

    DOE PAGES

    Baca, Albert G.; Armstrong, Andrew M.; Allerman, Andrew A.; ...

    2016-07-22

    An AlN barrier high electron mobility transistor (HEMT) based on the AlN/Al 0.85Ga 0.15N heterostructure was grown, fabricated, and electrically characterized, thereby extending the range of Al composition and bandgap for AlGaN channel HEMTs. An etch and regrowth procedure was implemented for source and drain contact formation. A breakdown voltage of 810 V was achieved without a gate insulator or field plate. Excellent gate leakage characteristics enabled a high I on/I off current ratio greater than 10 7 and an excellent subthreshold slope of 75 mV/decade. A large Schottky barrier height of 1.74 eV contributed to these results. In conclusion,more » the room temperature voltage-dependent 3-terminal off-state drain current was adequately modeled with Frenkel-Poole emission.« less

  11. Cryptanalysis and improvement of Yan et al.'s biometric-based authentication scheme for telecare medicine information systems.

    PubMed

    Mishra, Dheerendra; Mukhopadhyay, Sourav; Chaturvedi, Ankita; Kumari, Saru; Khan, Muhammad Khurram

    2014-06-01

    Remote user authentication is desirable for a Telecare Medicine Information System (TMIS) for the safety, security and integrity of transmitted data over the public channel. In 2013, Tan presented a biometric based remote user authentication scheme and claimed that his scheme is secure. Recently, Yan et al. demonstrated some drawbacks in Tan's scheme and proposed an improved scheme to erase the drawbacks of Tan's scheme. We analyze Yan et al.'s scheme and identify that their scheme is vulnerable to off-line password guessing attack, and does not protect anonymity. Moreover, in their scheme, login and password change phases are inefficient to identify the correctness of input where inefficiency in password change phase can cause denial of service attack. Further, we design an improved scheme for TMIS with the aim to eliminate the drawbacks of Yan et al.'s scheme.

  12. Theoretical analysis of compatibility of several reinforcement materials with NiAl and FeAl matrices

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.

    1989-01-01

    Several potential reinforcement materials were assessed for their chemical, coefficient of thermal expansion (CTE), and mechanical compatibility with the intermetallic matrices based on NiAl and FeAl. Among the ceramic reinforcement materials, Al2O3, TiC, and TiB2, appear to be the optimum choices for NiAl and FeAl matrices. However, the problem of CTE mismatch with the matrix needs to be solved for these three reinforcement materials. Beryllium-rich intermetallic compounds can be considered as potential reinforcement materials provided suitable reaction barrier coatings can be developed for these. Based on preliminary thermodynamic calculations, Sc2O3 and TiC appear to be suitable as reaction barrier coatings for the beryllides. Several reaction barrier coatings are also suggested for the currently available SiC fibers.

  13. Theoretical analysis of compatibility of several reinforcement materials with NiAl and FeAl matrices

    SciTech Connect

    Misra, A.K.

    1989-05-01

    Several potential reinforcement materials were assessed for their chemical, coefficient of thermal expansion (CTE), and mechanical compatibility with the intermetallic matrices based on NiAl and FeAl. Among the ceramic reinforcement materials, Al2O3, TiC, and TiB2, appear to be the optimum choices for NiAl and FeAl matrices. However, the problem of CTE mismatch with the matrix needs to be solved for these three reinforcement materials. Beryllium-rich intermetallic compounds can be considered as potential reinforcement materials provided suitable reaction barrier coatings can be developed for these. Based on preliminary thermodynamic calculations, Sc2O3 and TiC appear to be suitable as reaction barrier coatingsmore » for the beryllides. Several reaction barrier coatings are also suggested for the currently available SiC fibers.« less

  14. An AlN/Al{sub 0.85}Ga{sub 0.15}N high electron mobility transistor

    SciTech Connect

    Baca, Albert G.; Armstrong, Andrew M.; Allerman, Andrew A.; Douglas, Erica A.; Sanchez, Carlos A.; King, Michael P.; Coltrin, Michael E.; Fortune, Torben R.; Kaplar, Robert J.

    2016-07-18

    An AlN barrier high electron mobility transistor (HEMT) based on the AlN/Al{sub 0.85}Ga{sub 0.15}N heterostructure was grown, fabricated, and electrically characterized, thereby extending the range of Al composition and bandgap for AlGaN channel HEMTs. An etch and regrowth procedure was implemented for source and drain contact formation. A breakdown voltage of 810 V was achieved without a gate insulator or field plate. Excellent gate leakage characteristics enabled a high I{sub on}/I{sub off} current ratio greater than 10{sup 7} and an excellent subthreshold slope of 75 mV/decade. A large Schottky barrier height of 1.74 eV contributed to these results. The room temperature voltage-dependent 3-terminal off-state drain current was adequately modeled with Frenkel-Poole emission.

  15. Microstructure evolution during annealing of TiAl/NiCoCrAl multilayer composite prepared by EB-PVD

    SciTech Connect

    Zhang, Rubing, E-mail: zrb86411680@126.com; Zhang, Deming; Chen, Guiqing

    2014-07-01

    TiAl/NiCoCrAl laminate composite sheet with a thickness of 0.4–0.6 mm as well as a dimension of 150 mm × 100 mm was fabricated successfully by using electron beam physical vapor deposition (EB-PVD) method. The annealing treatment was processed at 1123 and 1323 K for 3 h in a high vacuum atmosphere, respectively. The phase composition and microstructure of TiAl/NiCoCrAl microlaminated sheet have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Based on the sheet characterization and results of the microstructure evolution during annealing treatment process, the diffusion mechanism of interfacial reaction in TiAl/NiCoCrAlmore » microlaminate was investigated and discussed.« less

  16. An AlN/Al{sub 0.85}Ga{sub 0.15}N high electron mobility transistor

    SciTech Connect

    Baca, Albert G.; Armstrong, Andrew M.; Allerman, Andrew A.

    2016-07-18

    An AlN barrier high electron mobility transistor (HEMT) based on the AlN/Al{sub 0.85}Ga{sub 0.15}N heterostructure was grown, fabricated, and electrically characterized, thereby extending the range of Al composition and bandgap for AlGaN channel HEMTs. An etch and regrowth procedure was implemented for source and drain contact formation. A breakdown voltage of 810 V was achieved without a gate insulator or field plate. Excellent gate leakage characteristics enabled a high I{sub on}/I{sub off} current ratio greater than 10{sup 7} and an excellent subthreshold slope of 75 mV/decade. A large Schottky barrier height of 1.74 eV contributed to these results. The room temperature voltage-dependent 3-terminalmore » off-state drain current was adequately modeled with Frenkel-Poole emission.« less

  17. Adhesive and tribocorrosive behavior of TiAlPtN/TiAlN/TiAl multilayers sputtered coatings over CoCrMo

    NASA Astrophysics Data System (ADS)

    Canto, C. E.; Andrade, E.; Rocha, M. F.; Alemón, B.; Flores, M.

    2017-09-01

    The tribocorrosion resistance and adherence of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by PVD reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt in order to enhance the tribocorrosion resistance of a biomedical alloy of CoCrMo. Tribocorrosion tests were performed using Simulated Body Fluid (SBF) at typical body temperature with a tribometer in a pin on disk test. The elemental composition and thickness of the coating which behave better at the tribocorrosion tests were evaluated by means of RBS (Rutherford Backscattering Spectroscopy) IBA (Ion Beam Analysis) technique, using an alpha particles beam of 1.8 MeV, before and after the reciprocating motion in the tribocorrosion test. In order to simulate the elemental profile of the samples, the SIMNRA simulation computer code was used. Measurements of the adhesion of the coatings to the substrate were carried on by means of a scratch test using a tribometer. By taking micrographs of the produced tracks, the critical loads at which the coatings are fully separated from the substrate were determined. From these tests it was observed that a coating with 10 min of TiAlPtN in a TiAlPtN/TiAl period of 30 min in multilayers of 10 periods and with an average thickness of 145 nm for the TiAlPtN nanolayers had the best tribocorrosion resistance behavior, compared to that of the CoCrMo alloy. The RBS experiments showed a reduction of the thickness of the films along with some loss of the multilayer structure after the reciprocating motion. The adhesion tests indicated that the multilayer with the average TiAlPtN thickness of 145 nm displayed the highest critical load. These results indicate a high correlation between the adherence and the tribocorrosion behavior.

  18. Comment on RamaRao et al. [1995] and LaVenue et al. [1995

    USGS Publications Warehouse

    Cooley, Richard L.; Hill, Mary C.

    2000-01-01

    A method for stochastic modeling of groundwater flow systems using a combination of pilot point parameterization and conditional simulation was presented by RamaRao et. al [1995] and LaVenue et. al [1995]. (We will collectively term these two papers RLMM and term the method developed in RLMM the CS method here.) RLMM (pp. 478-479) state that the CS method is intended to provide a frequency distribution of possible alternative spatial transmissivity T distributions that (1) are statistically similar to the observed T distribution, (2) are equally likely given the calibration data, and (3) closely reproduce the measured pressures. The frequency distribution of transmissivities is then used to form frequency distribution of derived functions, such as travel times, which are summarized in the form of uncertainty measures, such as (RLMM, p. 512) "confidence (or tolerance) intervals," on the actual values, which in the case of travels times, are values that could occur sometime in the future (RLMM, p.513). Cooley [2000] analyzes the RLMM method using linearization and bootstrap theory and concludes that that the method can yield accurate uncertainty estimates but only under some limited circumstances.  In this comment we use Cooley's analysis to critique the method. We also identify and discuss some statements made my by RLMM about model calibration and their methodology that appear to be misleading. It is unusual to comment on a paper so long after publication. Subsequent work has expanded the method of RLMM, and the method was used advantageously in the testing documented by Zimmerman et. al [1998], so it is clear the method has significant strengths. We go back to the 1995 papers for this comment, however, because they display most clearly the methodological difficulties with which we are concerned. 

  19. Lipidomics Reveals Cerebrospinal-Fluid Signatures of ALS.

    PubMed

    Blasco, H; Veyrat-Durebex, C; Bocca, C; Patin, F; Vourc'h, P; Kouassi Nzoughet, J; Lenaers, G; Andres, C R; Simard, G; Corcia, P; Reynier, P

    2017-12-15

    Amyotrophic lateral sclerosis (ALS), the commonest adult-onset motor neuron disorder, is characterized by a survival span of only 2-5 years after onset. Relevant biomarkers or specific metabolic signatures would provide powerful tools for the management of ALS. The main objective of this study was to investigate the cerebrospinal fluid (CSF) lipidomic signature of ALS patients by mass spectrometry to evaluate the diagnostic and predictive values of the profile. We showed that ALS patients (n = 40) displayed a highly significant specific CSF lipidomic signature compared to controls (n = 45). Phosphatidylcholine PC(36:4), higher in ALS patients (p = 0.0003) was the most discriminant molecule, and ceramides and glucosylceramides were also highly relevant. Analysis of targeted lipids in the brain cortex of ALS model mice confirmed the role of some discriminant lipids such as PC. We also obtained good models for predicting the variation of the ALSFRS-r score from the lipidome baseline, with an accuracy of 71% in an independent set of patients. Significant predictions of clinical evolution were found to be correlated to sphingomyelins and triglycerides with long-chain fatty acids. Our study, which shows extensive lipid remodelling in the CSF of ALS patients, provides a new metabolic signature of the disease and its evolution with good predictive performance.

  20. Oxide treatments of Al 2024 for adhesive bonding- surface characterization

    NASA Astrophysics Data System (ADS)

    Fin, N.; Dodiuk, H.; Yaniv, A. E.; Drori, L.

    1987-03-01

    A study was made to characterize the surface of oxides formed on Al 2024 in comparison to those formed on Al 1100, using Auger, ESCA, SIMS, FTIR and SEM/EDAX techniques. The pretreatments studied were chromate conversion coating, chromic acid anodizing and sulfuric acid anodizing. The specimens were evaluated as treated and after exposure to laboratory conditions ( T=25≠3°C and relative humidity of 60≠10%) for 6 months. In addition, a new surface pretreatment was studied, which was based on McDonnell Douglas P.S. 13201 specification. Adhesive bond strength of silicone rubbers and epoxy adhesives to pretreated Al 2024 was determined, using single lap joint specimens. It was shown that the main difference between the anodic coatings on Al 1100 and Al 2024 was the presence of copper on the surface in the latter. The presence of copper led us to postulate the mechanism of polymerization inhibition of 2 parts polysiloxane adhesive. The most suitable treatments for adhesive joining were found to be chromic acid sealed or unsealed anodizing for both Al 2024 and Al 1100. Our standard chromic acid anodizing gave higher bond strength for aluminum-adhesive joints than the "Douglas" process. as determined with several epoxy adhesives. Correlation between microscopic and macroscopic phenomena was established.

  1. On creep behavior in powder metallurgy 6061 Al

    SciTech Connect

    Mohamed, F.A.

    1998-01-06

    There has been a considerable interest in studying the creep characteristics of powder metallurgy (PM) Al alloys such as PM 6061 Al and PM 2124 Al. First, these alloys have been used as matrices in the development of discontinuous SiC-Al composites which have been under consideration as attractive materials for high temperature applications. Second, creep data on these alloys can be used not only to characterize the elevated temperature mechanical behavior of SiC-Al composites in terms of deformation mechanisms but also to provide a close comparison between the creep strength of a composite and its unreinforced matrix alloy. Such amore » comparison under similar experimental conditions may determine whether the composite is more creep resistant than the alloy. The purpose of this note is to examine the experimental results reported for PM 6061 Al in the light of the advances that have been made in rationalizing the creep behavior of Al-based solid-solution alloys.« less

  2. The multi-dimensional roles of astrocytes in ALS.

    PubMed

    Yamanaka, Koji; Komine, Okiru

    2018-01-01

    Despite significant progress in understanding the molecular and genetic aspects of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease characterized by the progressive loss of motor neurons, the precise and comprehensive pathomechanisms remain largely unknown. In addition to motor neuron involvement, recent studies using cellular and animal models of ALS indicate that there is a complex interplay between motor neurons and neighboring non-neuronal cells, such as astrocytes, in non-cell autonomous neurodegeneration. Astrocytes are key homeostatic cells that play numerous supportive roles in maintaining the brain environment. In neurodegenerative diseases such as ALS, astrocytes change their shape and molecular expression patterns and are referred to as reactive or activated astrocytes. Reactive astrocytes in ALS lose their beneficial functions and gain detrimental roles. In addition, interactions between motor neurons and astrocytes are impaired in ALS. In this review, we summarize growing evidence that astrocytes are critically involved in the survival and demise of motor neurons through several key molecules and cascades in astrocytes in both sporadic and inherited ALS. These observations strongly suggest that astrocytes have multi-dimensional roles in disease and are a viable therapeutic target for ALS. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Strength anomaly in B2 FeAl single crystals

    SciTech Connect

    Yoshimi, K.; Hanada, S.; Yoo, M.H.

    1994-12-31

    Strength and deformation microstructure of B2 Fe-39 and 48%Al single crystals (composition given in atomic percent), which were fully annealed to remove frozen-in vacancies, have been investigated at temperatures between room temperature and 1073K. The hardness of as-homogenized Fe-48Al is higher than that of as-homogenized Fe-39Al while after additional annealing at 698K the hardness of Fe-48Al becomes lower than that of Fe-39Al. Fe-39Al single crystals slowly cooled after homogenizing at a high temperature were deformed in compression as a function of temperature and crystal orientation. A peak of yield strength appears around 0.5T{sub m} (T{sub m} = melting temperature). Themore » orientation dependence of the critical resolved shear stress does not obey Schmid`s law even at room temperature and is quite different from that of b.c.c. metals and B2 intermetallics at low temperatures. At the peak temperature slip transition from <111>-type to <001>-type is found to occur macroscopically and microscopically, while it is observed in TEM that some of the [111] dislocations decompose into [101] and [010] on the (1096I) plane below the peak temperature. The physical sources for the positive temperature dependence of yield stress of B2 FeAl are discussed based on the obtained results.« less

  4. ALS pathophysiology: insights from the split-hand phenomenon.

    PubMed

    Menon, Parvathi; Kiernan, Matthew C; Vucic, Steve

    2014-01-01

    The aim of the present study was to assess whether peripheral mechanisms, mediated through axonal dysfunction, may contribute to development of the split-hand in amyotrophic lateral sclerosis (ALS). Median and ulnar nerve motor axonal excitability studies were undertaken on 21 ALS patients with motor responses recorded over the abductor pollicis brevis (APB), abductor digit minimi (ADM) and first dorsal interosseous (FDI) muscles, and results compared to 24 controls. The split-hand index (SI), an objective biomarker of preferential atrophy of APB and FDI muscles, was significantly reduced in ALS (SI(ALS) 7.8 ± 1.7, SICONTROLS 13.1 ± 1.1, P<0.0001). Axonal excitability studies identified significant prolongation of strength-duration time constant in ALS patients when recording over the APB (P<0.05) and ADM axons (P<0.05) but not FDI axons (P=0.22). Greater changes in depolarising threshold electrotonus were also evident across the range of intrinsic hand muscles and were accompanied by increases of superexcitability in APB (P<0.01) and FDI (P<0.05) axons. The present study reinforces the significance of the split-hand phenomenon in ALS and argues against a significant peripheral contribution in the underlying development. Axonal dysfunction may appear as a downstream process that develops secondary to the intrinsic pathophysiological origins of ALS. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  5. Atomically Thin Al2O3 Films for Tunnel Junctions

    NASA Astrophysics Data System (ADS)

    Wilt, Jamie; Gong, Youpin; Gong, Ming; Su, Feifan; Xu, Huikai; Sakidja, Ridwan; Elliot, Alan; Lu, Rongtao; Zhao, Shiping; Han, Siyuan; Wu, Judy Z.

    2017-06-01

    Metal-insulator-metal tunnel junctions are common throughout the microelectronics industry. The industry standard AlOx tunnel barrier, formed through oxygen diffusion into an Al wetting layer, is plagued by internal defects and pinholes which prevent the realization of atomically thin barriers demanded for enhanced quantum coherence. In this work, we employ in situ scanning tunneling spectroscopy along with molecular-dynamics simulations to understand and control the growth of atomically thin Al2O3 tunnel barriers using atomic-layer deposition. We find that a carefully tuned initial H2O pulse hydroxylated the Al surface and enabled the creation of an atomically thin Al2O3 tunnel barrier with a high-quality M -I interface and a significantly enhanced barrier height compared to thermal AlOx . These properties, corroborated by fabricated Josephson junctions, show that atomic-layer deposition Al2O3 is a dense, leak-free tunnel barrier with a low defect density which can be a key component for the next generation of metal-insulator-metal tunnel junctions.

  6. High-performance Ni3Al synthesized from composite powders

    NASA Astrophysics Data System (ADS)

    Chiou, Wen-Chih; Hu, Chen-Ti

    1994-05-01

    Specimens of Ni3Al + B of high density (>99.3 Pct RD) and relatively large dimension have been synthesized from composite powders through processes of replacing plating and electroless Ni-B plating on Al powder, sintering, and thermal-mechanical treatment. The uniformly coated Ni layer over fine Al or Ni core particles constituting these coating/core composite powders has advantages such as better resistance to oxidation relative to pure Al powder, a greater green density as a compacted powder than prealloyed powder, the possibility of atomically added B to the material by careful choice of a suitable plating solution, and avoidance of the expensive powder metallurgy (PM) equipment such as a hot isostatic press (HIP), hot press (HP), etc. The final Ni3Al + B product is made from Ni-B-Al and Ni-B-Ni mixed composite powders by means of traditional PM processes such as compacting, sintering, rolling, and annealing, and therefore, the dimensions of the product are not constrained by the capacity of an HIP or HP. The properties of Ni3Al composite powder metallurgy (CPM) specimens tested at room temperature have been obtained, and comparison with previous reports is conducted. A tensile elongation of about 16 Pct at room temperature was attained.

  7. Al-Anon Family Groups: Newcomers and Members

    PubMed Central

    Timko, Christine; Cronkite, Ruth; Kaskutas, Lee Ann; Laudet, Alexandre; Roth, Jeffrey; Moos, Rudolf H.

    2013-01-01

    Objective: Empirical knowledge is lacking about Al-Anon Family Groups (Al-Anon), the most widely used form of help by people concerned about another’s drinking, partly because conducting research on 12-step groups is challenging. Our purpose was to describe a new method of obtaining survey data from 12-step group attendees and to examine influences on initial Al-Anon attendance and attendees’ recent life contexts and functioning. Method: Al-Anon’s World Service Office sent a mailing to a random sample of groups, which subsequently yielded surveys from newcomers (n = 359) and stable members (n = 264). Results: Reasons for groups’ nonparticipation included having infrequent newcomers and the study being seen as either contrary to the 12 Traditions or too uncomfortable for newcomers. Main concerns prompting initial Al-Anon attendance were problems with overall quality of life and with the Al-Anon trigger (a significant drinking individual), and being stressed and angry. Goals for Al-Anon attendance were related to the following concerns: better quality of life, fewer trigger-related problems, and less stress. Members reported better functioning in some of these domains (quality of life, relationship with the trigger) but did not differ from newcomers on physical and psychological health. Newcomers were more likely to have recently drunk alcohol and to have obtained treatment for their own substance misuse problems. Conclusions: This method of collecting data from 12-step group attendees yielded valid data and also was seen by many in Al-Anon as consistent with the Traditions. Both newcomers and members had aimed to improve their overall quality of life and well-being through Al-Anon, and, indeed, members were more satisfied with their quality of life than were newcomers. PMID:24172125

  8. Al-Anon family groups: newcomers and members.

    PubMed

    Timko, Christine; Cronkite, Ruth; Kaskutas, Lee Ann; Laudet, Alexandre; Roth, Jeffrey; Moos, Rudolf H

    2013-11-01

    Empirical knowledge is lacking about Al-Anon Family Groups (Al-Anon), the most widely used form of help by people concerned about another's drinking, partly because conducting research on 12-step groups is challenging. Our purpose was to describe a new method of obtaining survey data from 12-step group attendees and to examine influences on initial Al-Anon attendance and attendees' recent life contexts and functioning. Al-Anon's World Service Office sent a mailing to a random sample of groups, which subsequently yielded surveys from newcomers (n = 359) and stable members (n = 264). Reasons for groups' nonparticipation included having infrequent newcomers and the study being seen as either contrary to the 12 Traditions or too uncomfortable for newcomers. Main concerns prompting initial Al-Anon attendance were problems with overall quality of life and with the Al-Anon trigger (a significant drinking individual), and being stressed and angry. Goals for Al-Anon attendance were related to the following concerns: better quality of life, fewer trigger-related problems, and less stress. Members reported better functioning in some of these domains (quality of life, relationship with the trigger) but did not differ from newcomers on physical and psychological health. Newcomers were more likely to have recently drunk alcohol and to have obtained treatment for their own substance misuse problems. This method of collecting data from 12-step group attendees yielded valid data and also was seen by many in Al-Anon as consistent with the Traditions. Both newcomers and members had aimed to improve their overall quality of life and well-being through Al-Anon, and, indeed, members were more satisfied with their quality of life than were newcomers.

  9. Structural evolution in mechanically alloyed Al-Fe powders

    SciTech Connect

    Mukhopadhyay, D.K.; Suryanarayana, C.; Froes, F.H.

    1995-08-01

    The structural evolution in mechanically alloyed binary aluminum-iron powder mixtures containing 1, 4, 7.3, 10.7, and 25 at pct Fe was investigated using X-ray diffraction (XRD) and electron microscopic techniques. The constitution (number and identity of phases present), microstructure (crystal size, particle size), and transformation behavior of the powders on annealing were studied. The solid solubility of Fe in Al has been extended up to at least 4.5 at. pct, which is close to that observed using rapid solidification (RS) (4.4 at. pct), compared with the equilibrium value of 0.025 at. pct Fe at room temperature. Nanometer-sized grains were observedmore » in as-milled crystalline powders in all compositions. Increasing the ball-to-powder weight ratio (BPR) resulted in a faster rate of decrease of crystal size. A fully amorphous phase was obtained in the Al-25 at. pct Fe composition, and a mixed amorphous phase plus solid solution of Fe in Al was developed in the Al-10.7 at. pct Fe alloy, agreeing well with the predictions made using the semiempirical Miedema model. Heat treatment of the mechanically alloyed powders containing the supersaturated solid solution or the amorphous phase resulted in the formation of the Al{sub 3}Fe intermetallic in all but the Al-25 at. pct Fe powders. In the Al-25 at. pct Fe powder, formation of nanocrystalline Al{sub 5}Fe{sub 2} was observed directly by milling. Electron microscope studies of the shock-consolidated mechanically alloyed Al-10.7 and 25 at. pct Fe powders indicated that nanometer-sized grains were retained after compaction.« less

  10. Effects of boron on the mechanical properties of the TiAl-Ti3Al alloy: A first-principles investigation

    NASA Astrophysics Data System (ADS)

    Li, Zhong-Zhu; Wei, Ye; Zhou, Hong-Bo; Lu, Guang-Hong

    2017-01-01

    Employing a first-principles method in combination with the empirical criterions, we have investigated the site preference of boron (B) and its effect on the mechanical properties of the binary-phase TiAl-Ti3Al alloy. It is found that B energetically prefers to occupy the Ti-rich octahedral interstitial site, because B is more favorable to bond with Ti in comparison with Al. The occupancy tendency of B in the TiAl-Ti3Al alloy is the TiAl/Ti3Al interface > Ti3Al > TiAl, thus B tends to segregate into the binary-phase interface in the TiAl-Ti3Al alloy. The charge density difference shows that B at the TiAl-Ti3Al interface will form strong B-Ti bonds and weak B-Al bonds, leading to the significant increasing of the cleavage energy (γcl) and the unstable stacking fault energy (γus). This indicates that the presence of B will strengthen the TiAl/Ti3Al interface, but block its mobility. Further, the ratio of γcl/γus of the B-doped system is 4.63%, 8.19% lower than that of the clean system. Based on the empirical criterions, B will have a negative effect on the ductility of the TiAl-Ti3Al alloy.

  11. Crystal structure of hexagonal MnAl4

    PubMed Central

    Pauling, Linus

    1987-01-01

    A structure is proposed for the hexagonal form of MnAl4, with aH = 28.4 Å and cH = 12.43 Å, on the basis of a high-resolution electron micrograph and comparison with crystals of known structures. The proposed structure involves seven 104-atom complexes of 20 Friauf polyhedra, sharing some atoms with one another. It is closely related to the 23.36-Å cubic structure of MnAl4 and to the 14.19-Å cubic structure of Mg32(Al,Zn)49. Images PMID:16593837

  12. ALS user meeting features 10th anniversary celebration

    SciTech Connect

    Robinson, Art

    2003-12-05

    The Advanced Light Source (ALS) saw first light on October 5, 1993, not quite to the day but close to 10 years before the 2003 ALS Users Association meeting, held October 6-8. Fittingly, the proceedings included retrospectives from two of the key players in the early history of the ALS, David Attwood and Jay Marx, and a display of photographs chronicling its construction and commissioning. Science highlights, highlights from young researchers, and posters constituted the meat of the program on Monday and Tuesday morning, while workshops took over Tuesday afternoon and all day Wednesday.

  13. Itinerant magnetism in CaMn2Al10

    NASA Astrophysics Data System (ADS)

    Simonson, Jack; Steinke, Lucia; Zellman, Shelby; Kistner-Morris, Jedediah; Puri, Akshat; Andrews, Evon; Aronson, Meigan

    2015-03-01

    We report the synthesis and basic properties of CaMn2Al10, a new itinerant magnet that is nearly isostructural with the known quantum critical compound YFe2Al10. Magnetic susceptibility measurements performed on single crystals reveal a cusp at 2 K. Electrical resistivity measurements similarly have a maximum at this temperature, and heat capacity measurements show a broad peak with total entropy of ~ 10 % R ln2. These results together with those of neutron diffraction measurements suggest that CaMn2Al10 is weakly magnetic and potentially close to a quantum critical point. Research supported by a DOD National Security Science and Engineering Fellowship via the AFOSR.

  14. Evaluation of Ti-48Al-2Nb Under Fretting Conditions

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa; Lerch, Bradley A.; Draper, Susan L.; Raj, Sai V.

    2001-01-01

    An investigation was conducted to examine the fretting behavior of lambda-TiAl (Ti-48Al-2Cr-2Nb) in contact with a nickel-base superalloy (Inconel 718) in air at temperatures from 23 to 550 C. Fretting wear experiments were conducted with 9.4-mm-diameter hemispherical Inconel (IN) 718 pins in contact with Ti-48Al-2Cr-2Nb flats (and the reverse) at loads from 1 to 40 N and fretting frequencies from 50 to 160 Hz with slip amplitudes from 50 to 200 microns for 1 to 20 million fretting cycles. The results were similar for both combinations of pin and flat. Reference fretting wear experiments were also conducted with 9.4-mm-diameter hemispherical Ti-6Al-4V pins in contact with IN718 flats. The interfacial adhesive bonds between Ti-48Al-2Cr-2Nb and IN718 in contact were generally stronger than the cohesive bonds in the cohesively weaker Ti-48Al-2Cr-2Nb. The failed Ti-48Al-2Cr-2Nb subsequently transferred to the IN718 surface at any fretting condition. The wear scars produced on Ti-48Al-2Cr-2Nb contained metallic and oxide wear debris, scratches, plastically deformed asperities, cracks, and fracture pits. Oxide layers readily formed on the Ti-48Al-2Cr-2Nb surface at 550 C, but cracks easily occurred in the oxide layers. Factors including fretting frequency, temperature, slip amplitude, and load influenced the fretting behavior of Ti-48Al-2Cr-2Nb in contact with IN718. The wear volume loss of Ti-48Al-2Cr-2Nb generally decreased with increasing fretting frequency. The increasing rate of oxidation at elevated temperatures up to 200 C led to a drop in wear volume loss at 200 C. However, the fretting wear increased as the temperature was increased from 200 to 550 C. The highest temperatures of 450 and 550 C resulted in oxide film disruption with generation of cracks, loose wear debris, and pits on the Ti-48Al-2Cr-2Nb wear surface. The wear volume loss generally increased as the slip amplitude increased. The wear volume loss also generally increased as the load increased

  15. Lattice crossover and phase transitions in NdAlO{sub 3}-GdAlO{sub 3} system

    SciTech Connect

    Vasylechko, L.; Shmanko, H.; Ohon, N.; Prots, Yu.; Hoffmann, S.; Ubizskii, S.

    2013-02-15

    Phase and structural behaviour in the (1-x)NdAlO{sub 3}-xGdAlO{sub 3} system in a whole concentration range has been studied by means of in situ high-resolution X-ray synchrotron powder diffraction technique and differential thermal analysis. Two kinds of solid solutions Nd{sub 1-x}Gd{sub x}AlO{sub 3} have been found at room temperature: one with rhombohedral (x<0.15) and one with orthorhombic (x{>=}0.20) symmetry. A morphotropic phase transition occurs at x Almost-Equal-To 0.15, where the co-existence of both phases was observed. Peculiarity of the orthorhombic solid solution is the lattice parameter crossover at the compositions with x=0.33, 0.49 and 0.62. First-order structural transition Pbnm{r_reversible}R3{sup Macron }c has been detected both from in situ powder diffraction and thermal analysis data. Continuous phase transformation R3{sup Macron }c{r_reversible}Pm3{sup Macron }m above 2140 K has been predicted for Nd-rich sample Nd{sub 0.85}Gd{sub 0.15}AlO{sub 3} from the extrapolation of high-temperature behaviour of the lattice parameter ratio of the rhombohedral phase. Based on the experimental data, the phase diagram of the pseudo-binary system NdAlO{sub 3}-GdAlO{sub 3} has been constructed. - Graphical abstract: Concentration dependencies of normalized lattice parameters of Nd{sub 1-x}Gd{sub x}AlO{sub 3} perovskite solid solutions. Highlights: Black-Right-Pointing-Pointer Two kinds of solid solutions Nd{sub 1-x}Gd{sub x}AlO{sub 3} were found in the NdAlO{sub 3}-GdAlO{sub 3} system. Black-Right-Pointing-Pointer Morphotropic transition between both perovskite phases occurs at x Almost-Equal-To 0.15. Black-Right-Pointing-Pointer Lattice parameter crossover was found in orthorhombic solid solution. Black-Right-Pointing-Pointer Temperature driven first-order phase transition Pbnm{r_reversible}R3{sup Macron }c was found in Nd{sub 1-x}Gd{sub x}AlO{sub 3}. Black-Right-Pointing-Pointer Phase diagram of the pseudo-binary system NdAlO{sub 3}-GdAlO{sub 3} has been

  16. A Data-Driven Approach for Characterization of Ternary Al(fcc)-Al2Cu(tet)-Ag2Al(hcp) Eutectic Alloys

    NASA Astrophysics Data System (ADS)

    Sargin, Irmak; Beckman, Scott

    We present a new data-driven approach to characterize the microstructure of the ternary eutectic Al-Ag2Al-Al2Cu alloy. In this approach a range of microstructural descriptors are developed and used within the PCA and PLSR analysis methods. The similarity between the ideal microstructures and those experimentally obtained are quantified and the percentage similarity to ideal structures is used as a new means for cataloguing microstructures. This quantified comparison of the idealized structures to the experimental ones provides insight about the microstructural evolution. Such an approach can be applied to many different areas of materials science allowing the important relationships between microstructure and physical properties to be identified. This form of analysis allows determination of which deviations from the ideal attributes result in variation from the ideal physical properties.

  17. The effect of AlN/AlGaN superlattices on crystal and optical properties of AlGaN epitaxial layers

    NASA Astrophysics Data System (ADS)

    Zhang, Shuo; Zhang, Yun; Chen, Xiang; Guo, Yanan; Yan, Jianchang; Wang, Junxi; Li, Jinmin

    2017-11-01

    We investigate the effect of AlN/AlGaN superlattices (SLs) on crystal and optical properties of AlGaN epitaxial layers. The result indicates that the crystal quality of AlGaN layers is consistent within a wide range of SLs thicknesses, while the optical properties are opposite. With SLs thickness decreasing from 20/44 to 17/36 and 15/29 nm, the full-width at half maximum of X-ray rocking curves for (0002)- and ( 10\\bar 12)-plane of n-AlGaN layers grown on SLs are consistent of around 250 arcsec and 700 arcsec, respectively. Meanwhile, the center of the low optical transmittance band decreases from 326 to 279 nm and less than 266 nm as the SLs thickness decreases. 280 nm deep ultraviolet light-emitting diodes (DUV-LEDs) structures are further regrown on the n-AlGaN layers. The electroluminescent intensities of samples are 30% higher than that of the sample whose low optical transmittance band appears around 279 nm. Optical simulations reveal that the SLs acts as distributed Bragg reflectors, thus less photons of the corresponding wavelength escape from the sapphire backside. Project supported in part by the National High Technology Program of China (No. 2014AA032608), the National Key R&D Program of China (Nos. 2016YFB0400800, 2016YFB0400083, 2016YFB0400082), in part by the National Natural Sciences Foundation of China (Nos. 6136047, 61206090, 61527814, 61674147, 61204053), the Beijing Municipal Science and Technology Project (No. D161100002516002), the National 1000 Young Talents Program, and the Youth Innovation Promotion Association, CAS.

  18. Surgery for Gynecomastia in the Islamic Golden Age: Al-Tasrif of Al-Zahrawi (936–1013 AD)

    PubMed Central

    Chavoushi, Seyed Hadi; Ghabili, Kamyar; Kazemi, Abdolhassan; Aslanabadi, Arash; Babapour, Sarah; Ahmedli, Rafail; Golzari, Samad E. J.

    2012-01-01

    The rise of European science during the Renaissance is greatly indebted to the flourishing of the sciences during the Islamic Golden Age. However, some believe that medieval Islamic physicians and in particular surgeons had been merely a medium for Greco-Roman ideas. Contrarily, in some medieval Islamic medical books, such as Al-Tasrif of Al-Zahrawi (936–1013), the surgical instructions represent a change in the usual techniques or are accompanied by a case history, implying that the procedure was actually undertaken. Along with the hundreds of chapters on different diseases and related medical and surgical treatments, Al-Tasrif includes a chapter on surgical techniques for gynecomastia. The present paper is a review of the description of the surgical management of gynecomastia by Al-Zahrawi as well as that of the ancient Greek, medieval, and modern medicine. Although Al-Zahrawi seemed to base his descriptions of surgery for gynecomastia upon those of Paulus of Aegina, his modification of the procedure and application of the medicinal substances might be indicative of Al-Zahrawi's own practice of the procedure. Al-Zahrawi's surgical procedures remained unchanged for many centuries thenceforward until the technological evolution in the recent centuries. PMID:23050167

  19. Growth of C60 thin films on Al2O3/NiAl(100) at early stages

    NASA Astrophysics Data System (ADS)

    Hsu, S.-C.; Liao, C.-H.; Hung, T.-C.; Wu, Y.-C.; Lai, Y.-L.; Hsu, Y.-J.; Luo, M.-F.

    2018-03-01

    The growth of thin films of C60 on Al2O3/NiAl(100) at the earliest stage was studied with scanning tunneling microscopy and synchrotron-based photoelectron spectroscopy under ultrahigh-vacuum conditions. C60 molecules, deposited from the vapor onto an ordered thin film of Al2O3/NiAl(100) at 300 K, nucleated into nanoscale rectangular islands, with their longer sides parallel to direction either [010] or [001] of NiAl. The particular island shape resulted because C60 diffused rapidly, and adsorbed and nucleated preferentially on the protrusion stripes of the crystalline Al2O3 surface. The monolayer C60 film exhibited linear protrusions of height 1-3 Å, due to either the structure of the underlying Al2O3 or the lattice mismatch at the boundaries of the coalescing C60 islands; such protrusions governed also the growth of the second layer. The second layer of the C60 film grew only for a C60 coverage >0.60 ML, implying a layer-by-layer growth mode, and also ripened in rectangular shapes. The thin film of C60 was thermally stable up to 400 K; above 500 K, the C60 islands dissociated and most C60 desorbed.

  20. Phase transformations, heat evolution, and atomic diffusion during slow heating of Al-rich Al/Zr multilayered foils

    SciTech Connect

    Fisher, Kaitlynn; Barron, S. C.; Knepper, R.

    2013-12-28

    We describe the energy and sequence of phase transformations in multilayered Al/Zr foils with atomic ratios of 3 Al:1 Zr during low temperature (<350 °C) heat treatments in a differential scanning calorimeter. The initial phase formed is an Al-rich amorphous phase that appears to grow by Zr diffusion through the amorphous phase. The subsequent nucleation and growth of tetragonal Al{sub 3}Zr along the Al/amorphous layer interface is mediated by Al diffusion through the crystalline intermetallic phase. Diffusion coefficients associated with these processes are higher than expected from reports of diffusivities measured at higher temperatures. The inferred heat of formation of themore » tetragonal Al{sub 3}Zr phase is 1240 ± 40 J/g (53 ± 2 kJ/mol atom). No anomalous variation in the energy or sequence of phase transformations is found with bilayer thickness for samples with bilayer thickness in the range of 17 nm to 90 nm despite anomalies in the bilayer dependence of self-propagating reaction velocities in the same foils.« less

  1. Effect of the Al-Zr-Y master alloy composition on the modifying effect in the Al-4% Cu alloy

    NASA Astrophysics Data System (ADS)

    Popova, E. A.; Kotenkov, P. V.

    2016-02-01

    The results of modifying the Al-4% Cu alloy with test Al-1.04% Zr-0.70% Y and Al-1.23% Zr-0.39% Y master alloys are reported; the Zr-to-Y atomic-percentage ratio in the alloys is 1.41 and 3.08, respectively. The effect of small amounts of Zr and Y (from 0.1 to 0.3%) added in the form of test ternary master alloys of different compositions and binary Al-Zr and Al-Y master alloys on the grain refinement in the Al-4% Cu alloy has been studied. The structure of the initial alloy is characterized by pronounced directional solidification of the α phase. As the Zr + Y content increases, the columnar-crystal zone decreases and the equiaxed-crystal zone increases; at a (Zr + Y) content of 0.326%, only equiaxed crystals ~200 μm in size are present in an ingot. When Zr and Y are added with binary master alloys, the macrostructure of the modified Al-4% Cu alloys indicates that columnar crystals grow until their contact at the center of the ingot, and their growth is independent of the amount of added Zr and Y.

  2. Characterization of Al/crystallized Al-based metallic glass composites produced by repeated roll bonding process

    NASA Astrophysics Data System (ADS)

    Alizadeh, Morteza; Khoramkhorshid, Saba; Taghvaei, Amir Hossein; Gokuldoss, Prashanth Konda

    2017-07-01

    Devitrified Al84Gd6Ni7Co3 glassy particles have been used to reinforce Al-matrix composites through repeated roll bonding (RRB) process. Microstructural characterization of the produced composites after various rolling cycles was performed by scanning electron microscopy. Mechanical properties of the fabricated composites were evaluated by the tensile and microhardness tests. The results indicate that the RRB process is successful to produce composites with the negligible amount of flaws and porosity, and it is followed by homogeneous distribution of Al84Gd6Ni7Co3 particles in the Al matrix after nine rolling passes. Elongation of the composites improves significantly upon RRB cycles and the tensile strength and microhardness of them increase more than two times compared to unreinforced Al. According to fractography results, the enhanced mechanical properties are correlated with formation of excellent bonding at the interface of Al84Gd6Ni7Co3 particles and Al matrix. The theoretical values of composites hardness and yield strength calculated based on iso-strain model show a good agreement with respect to the experimental results.

  3. RETRACTED ARTICLE: Investigation on heterogeneous nucleation of MgAl2O4 in Al-Mg alloys

    NASA Astrophysics Data System (ADS)

    Haghayeghi, R.; Kapranos, P.

    2015-05-01

    This work investigates the mechanisms of grain refinement of Al-Mg alloys through ultrasonic treatment and varying Mg content. MgAl2O4 particles display an equiaxed and faceted morphology with {111} planes and when exposed to {111} of α-Al, can act as heterogeneous and potent nuclei for aluminium. Intensive vibrations by ultrasonic treatment lead to significant grain refinement through effective dispersion of MgAl2O4 particles. The equiaxed and faceted morphology of MgAl2O4 along with a well-defined cube-on-cube orientation relationship (1bar 11)[110] MgAl2O4//(1bar 11)[110] α-Al, provide improved refinement. Furthermore, multiplication of solidification sites by the ultrasonic pulses enhances heterogeneous nucleation. The resulting improved grain refinement relates in all probability to the increased nucleation sites, due to grain multiplications and wetting of impurities, the lowering of surface tension due to the segregation of magnesium to the surface of liquid aluminium, the appropriate growth restriction factor and the low lattice mismatch coupled with strong dispersion of oxides.The filtration test confirms these particles as potent refiners.

  4. The Effectiveness of Al-Si Coatings for Preventing Interfacial Reaction in Al-Mg Dissimilar Metal Welding

    NASA Astrophysics Data System (ADS)

    Wang, Yin; Al-Zubaidy, Basem; Prangnell, Philip B.

    2018-01-01

    The dissimilar welding of aluminum to magnesium is challenging because of the rapid formation of brittle intermetallic compounds (IMC) at the weld interface. An Al-Si coating interlayer was selected to address this problem, based on thermodynamic calculations which predicted that silicon would change the reaction path to avoid formation of the normally observed binary Al-Mg IMC phases ( β-Al3Mg2 and γ-Al12Mg17). Long-term static heat treatments confirmed that a Si-rich coating will preferentially produce the Mg2Si phase in competition with the less stable, β-Al3Mg2 and γ-Al12Mg17 binary IMC phases, and this reduced the overall reaction layer thickness. However, when an Al-Si clad sheet was tested in a real welding scenario, using the Refill™ friction stir spot welding (FSSW) technique, Mg2Si was only produced in very small amounts owing to the much shorter reaction time. Surprisingly, the coating still led to a significant reduction in the IMC reaction layer thickness and the welds exhibited enhanced mechanical performance, with improved strength and fracture energy. This beneficial behavior has been attributed to the softer coating material both reducing the welding temperature and giving rise to the incorporation of Si particles into the reaction layer, which toughened the brittle interfacial IMC phases during crack propagation.

  5. Current issues in ALS epidemiology: Variation of ALS occurrence between populations and physical activity as a risk factor.

    PubMed

    Luna, J; Logroscino, G; Couratier, P; Marin, B

    2017-05-01

    Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disease with a fatal outcome. This review aims to report key epidemiological features of ALS in relation to the hypothesis of variation between populations, to summarize environmental hypothesis and to highlight current issues that deserve much considerations. Epidemiological ALS studies have shown a variation of incidence, mortality and prevalence between geographical areas and different populations. These data could support the notion that genetic factors, especially populations' ancestries, along with environmental and lifestyle factors, play a significant role in the occurrence of the disease. To date, there is no strong evidence to confirm an association between a particular environmental factor and ALS. Physical activity (PA) has been extensively evaluated. Recent studies support with the best evidence level that PA in general population is not a risk factor for ALS. However, further research is needed to clarify the association of PA in some occupations and some athletic activities. Epidemiological research based on multicenter international collaboration is essential to provide new data on ALS especially in some regions of the world that are to date poorly represented in the ALS literature. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Identification of phases in the interaction layer between U-Mo-Zr/Al and U-Mo-Zr/Al-Si

    SciTech Connect

    Varela, C.L. Komar; Arico, S.F.; Mirandou, M.

    2008-07-15

    Out-of-pile diffusion experiments were performed between U-7wt.% Mo-1wt.% Zr and Al or Al A356 (7,1wt.% Si) at 550 deg. C. In this work morphological characterization and phase identification on both interaction layer are presented. They were carried out by the use of different techniques: optical and scanning electron microscopy, X-Ray diffraction and WDS microanalysis. In the interaction layer U-7wt.% Mo-1wt.% Zr/Al, the phases UAl{sub 3}, UAl{sub 4}, Al{sub 20}Mo{sub 2}U and Al{sub 43}Mo{sub 4}U{sub 6} were identified. In the interaction layer U-7wt.% Mo-1wt.% Zr/Al A356, the phases U(Al, Si) with 25at.% Si and Si{sub 5}U{sub 3} were identified. This lastmore » phase, with a higher Si concentration, was identified with XRD Synchrotron radiation performed at the National Synchrotron Light Laboratory (LNLS), Campinas, Brasil. (author)« less

  7. Investigation of the site occupation of atoms in pure and doped TiAl/Ti3Al intermetallic.

    PubMed

    Boll, T; Al-Kassab, T; Yuan, Y; Liu, Z G

    2007-09-01

    Dual-phase TiAl/Ti3Al-alloys consisting of a lamellar structure, comprising gamma-phase plus a small amount of alpha2-phase, with addition of 1, 5 and 10at% Nb were prepared. The samples were investigated by means of field ion microscopy (FIM) and atom probe tomography (APT). The influence of doping elements on the variation of field evaporation and microstructural parameters in the gamma-phase as studied by FIM and APT will be reported in this contribution. The intermetallic gamma-Phase of TiAl exhibits a L1(0)-structure, which has alternating Ti- and Al-planes in the [001]-superstructure direction. Because of the significant difference in the evaporation field strengths of Ti and Al, it is usually not possible to directly distinguish Ti- and Al-planes in this direction in the APT data. Therefore, it is not possible to assign Nb to any plane, as well. To solve this problem an algorithm, using statistical methods, was developed, which allows to inherently distinguish the planes. A comparison of the results for [100]- and [001]-directions shows that Nb prefers Ti-sites. The sequence of field evaporation field strengths, which follows the trend E(Nb) > E(Al) > E(Ti), could also be deduced.

  8. Oxidation Behavior of Thermal Barrier Coatings with a TiAl3 Bond Coat on γ-TiAl Alloy

    NASA Astrophysics Data System (ADS)

    Wang, Jiqiang; Kong, Lingyan; Li, Tiefan; Xiong, Tianying

    2015-02-01

    The thermal barrier coatings investigated in this paper included a TiAl3 bond coat and a yttria partially stabilized zirconia (YSZ) layer. The TiAl3 bond coat was prepared by deposition of aluminum by cold spray, followed by a heat-treatment. The YSZ layer was prepared by air plasma spray. The isothermal and cyclic oxidation tests were conducted at 900 °C for 1000 h and 500 cycles to test the oxidation resistance of the thermal barrier coatings. The microstructure and composition of the γ-TiAl alloy with and without the thermal barrier coatings after oxidation were investigated. The results showed that a dense TGO layer about 5 μm had grown between the YSZ layer and the TiAl3 bond coat. The TGO had good adhesion to both the YSZ layer and the bond coat even after the TiAl3 bond coat entirely degraded into the TiAl2 phase, which decreased the inward oxygen diffusion. Thus, the thermal barrier coatings improved the oxidation resistance of γ-TiAl alloy effectively.

  9. Effect of annealing temperature on Ti/Al/Ni/Au ohmic contacts on undoped AlN films

    NASA Astrophysics Data System (ADS)

    Li, Xuewei; Zhang, Jicai; Sun, Maosong; Ye, Binbin; Huang, Jun; Xu, Zhenyi; Dong, Wenxiu; Wang, Jianfeng; Xu, Ke

    2017-11-01

    The Ti/Al/Ni/Au metals were deposited on undoped AlN films by electron beam evaporation. The influence of annealing temperature on the properties of contacts was investigated. When the annealing temperatures were between 800 and 950 °C, the AlN–Ti/Al/Ni/Au contacts became ohmic contacts and the resistance decreased with the increase of annealing temperature. A lowest specific contacts resistance of 0.379 Ω·cm 2 was obtained for the sample annealed at 950 °C. In this work, we confirmed that the formation mechanism of ohmic contacts on AlN was due to the formation of Al–Au, Au–Ti and Al–Ni alloys, and reduction of the specific contacts resistance could originate from the formation of Au 2Ti and AlAu2 alloys. This result provided a possibility for the preparation of AlN-based high-frequency, high-power devices and deep ultraviolet devices.

  10. Low resistance ohmic contacts to n-GaN and n-AlGaN using NiAl

    NASA Astrophysics Data System (ADS)

    Ingerly, D. B.; Chen, Y.; William, R. S.; Takeuchi, T.; Chang, Y. A.

    2000-07-01

    The intermetallic compound NiAl (50:50 at. %) has been shown to be a low-resistance ohmic contact to n-GaN and n-AlGaN. NiAl contacts on n-GaN (n=2.5×1017cm-3) had a specific contact resistance of 9.4×10-6 Ω cm2 upon annealing at 850 °C for 5 min. NiAl contacts annealed at 900 °C for 5 min in n-Al0.12Ga0.88N (n=2.4×1018cm-3) and n-Al0.18Ga0.82N (n=2.7×1018cm-3) had specific contact resistances of 2.1×10-5 Ω cm2 and 4.7×10-5 Ω cm2, respectively. Additionally, these contacts were subjected to long-term annealing at 600 °C for 100 h. On n-GaN, the contact specific contact resistance degraded from 9.4×10-6 Ω cm2 to 5.3×10-5 Ω cm2 after the long-term anneal. Contacts to n-Al0.18Ga0.82N showed only slight degradation with a change in contact resistance, from 4.7×10-5 Ω cm2 to 9.2×10-5 Ω cm2. These results demonstrate the NiAl has great promise as a stable, low-resistance contact, particularly to n-AlGaN used in high-temperature applications.

  11. Thermophysical Properties of Liquid AlTi-Based Alloys

    NASA Astrophysics Data System (ADS)

    Egry, I.; Holland-Moritz, D.; Novakovic, R.; Ricci, E.; Wunderlich, R.; Sobczak, N.

    2010-05-01

    The surface tension and density of three liquid AlTi-based alloys (AlTiV, AlTiNb, and AlTiTa) have been measured using electromagnetic levitation as a tool for containerless processing. Surface tension has been determined by the oscillating-drop method, while the density was measured using a shadowgraph technique. Both quantities were determined over a wide temperature range, including the undercooled regime. In addition, sessile-drop and pendant-drop experiments to determine the surface tension were performed in a recently built high-temperature furnace. The measured data were compared to thermodynamic calculations using phenomenological models and the Butler equation. Generally, good agreement was found.

  12. 78 FR 36411 - Amendment of Class E Airspace; Tuskegee, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-18

    ... Tuskegee, AL, as the Tuskegee VOR/DME has been decommissioned and airspace reconfiguration is necessary for... reconfiguration is necessary due to the decommissioning of the Tuskegee VOR/DME and cancellation of the VOR...

  13. 75 FR 51239 - University of Massachusetts Amherst, et al.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-19

    ... International Trade Administration University of Massachusetts Amherst, et al.; Notice of Consolidated Decision... Avenue., NW., Washington, DC. Docket Number: 10-044. Applicant: University of Massachusetts Amherst... University, Boone, NC 28608. Instrument: Electron Microscope. Manufacturer: JEOL, Ltd., Japan. Intended Use...

  14. RadNet Air Data From Montgomery, AL

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Montgomery, AL from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  15. RadNet Air Data From Birmingham, AL

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Birmingham, AL from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  16. Co adsorption on Al-Zr at room temperature

    SciTech Connect

    Wu, C.H.; Moore, R.L.; Cohen, S.A.

    1981-04-01

    A study of CO adsorption on room temperature Al--Zr has been done using Auger electron spectroscopy and gas pressure measurements. The atomic surface composition of clean Al--Zr surfaces prepared in UHV by Ar/sup +/ sputtering was measured as a function of CO pressure and exposure time. The adsorbed C and O have the same rate constants and surface concentrations for exposures less than 2 Langmuir. Above this exposure quasi-saturation occurs. The measured sticking probability of CO on Al--Zr is constant, S = 0.7 +- 0.3, for fractional coverage q< or approx. =0.5. Above this point S decreased rapidly. The effectmore » of surface roughness on the apparent sticking coefficient has been calculated by a Monte Carlo simulation. Reactivation of Al--Zr by heat treatment to 700 /sup 0/C has also been studied.« less

  17. CO adsorption on Al-Zr at room temperature

    SciTech Connect

    Wu, C.H.; Moore, R.L.; Cohen, S.A.

    1980-10-01

    A study of CO adsorption on room temperature Al-Zr has been done using Auger electron spectroscopy and gas pressure measurements. The atomic surface composition of clean Al-Zr surfaces prepared in UHV by Ar/sup +/ sputtering, was measured as a function of CO pressure and exposure time. The adsorbed C and O have the same rate constants and surface concentrations for exposures less than 2 Langmuir. Above this exposure quasi-saturation occurs. The measured sticking probability of CO on Al-Zr is constant, S = 0.7 +- .3, for fractional coverage theta less than or equal to 0.5. Above this point S decreasedmore » rapidly. The effect of surface roughness on the apparent sticking coefficient has been calculated by a Monte-Carlo simulation. Reactivation of Al-Zr by heat treatment to 700/sup 0/C has also been studied.« less

  18. AlGaAs diode pumped tunable chromium lasers

    DOEpatents

    Krupke, William F.; Payne, Stephen A.

    1992-01-01

    An all-solid-state laser system is disclosed wherein the laser is pumped in the longwave wing of the pump absorption band. By utilizing a laser material that will accept unusually high dopant concentrations without deleterious effects on the crystal lattice one is able to compensate for the decreased cross section in the wing of the absorption band, and the number of pump sources which can be used with such a material increases correspondingly. In a particular embodiment a chromium doped colquiriite-structure crystal such as Cr:LiSrAlF.sub.6 is the laser material. The invention avoids the problems associated with using AlGaInP diodes by doping the Cr:LiSrAlF.sub.6 heavily to enable efficient pumping in the longwave wing of the absorption band with more practical AlGaAs diodes.

  19. The Complete Genome Sequence of Bacillus thuringiensis AlHakam

    SciTech Connect

    Challacombe, Jean F.; Altherr, Michael R.; Xie, Gary

    2007-04-01

    Bacillus thuringiensis is an insect pathogen that is widelyused as a biopesticide (3). Here we report the finished, annotated genomesequence of B. thuringiensis Al Hakam, which was collected in Iraq by theUnited Nations Special Commission (2).

  20. 76 FR 54188 - Television Broadcasting Services; Montgomery, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-31

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; Montgomery, AL AGENCY: Federal Communications... 73 Television, Television broadcasting. Federal Communications Commission. Barbara A. Kreisman, Chief...