Science.gov

Sample records for mobbing al gallego

  1. [Workplace mobbing].

    PubMed

    Soljan, Ivana; Josipović-Jelić, Zeljka; Jelić Kis, I Anita

    2008-03-01

    Workplace mobbing is a hostile and unethical communication, systematically aimed from one or more individuals towards mostly one individual, who are forced into a helpless position and are held in it by constant bullying. This article describes some of the most important characteristics of mobbing: offensive behaviour, organizational and non-organizational causes of this behaviour, the victim and the consequences. Modern business environment is complex, dynamic, volatile, and requires better ability to adjust. Constant changes are a part of organizational reality, but they also produce an ideal environment for all kinds of conflicts. Conflicts are inevitable in every organization, but the task of its management is to identify them and resolve before they affect the workforce, productivity and costs. The idea is to avert psychological abuse and aberrant behaviour such as mobbing which that may cause physical and mental disorders. Mobbing is a problem of the modern society; as a violation of human rights it is relatively new and unrecognised in Croatia. Abuse is mostly psychological: it affects the victim's health and life, quality of work, productivity, profitability, and may lead to significant economic losses in the community. Mobbing can be averted by joint forces that would involve employee and management, medical and legal professionals, and even community as a whole. The more an organization pursues excellence based on trust and business ethics, the higher the probability that mobbing will be averted or stopped. PMID:18411493

  2. Mobbing and Stress

    ERIC Educational Resources Information Center

    Yaman, Erkan

    2015-01-01

    Mobbing is an important construct which has impact on the numerous psychological variables. The purpose of this study is to examine the relationships between mobbing and stress. Participants were 436 teachers (206 (55%) were female, 230 (45%) were male) from Sakarya, Turkey. Their ages ranged from 26 to 55 years and the mean age of the…

  3. [Fitness, disability and mobbing].

    PubMed

    Magnavita, N; Bosco, M G; Ranalletta, D; Salerno, S

    2006-01-01

    Workers with handicap or psychological impairment are frequently submitted to mobbing. If causative factors of psychological disorders are not recognized, the physician charged of medical surveillance of workers may himself become a prosecutor and enhance the mobbing actions to the extent that the mobbed worker is discharged. In order to avoid this undue effect, the physician should strictly adhere to the body of legislation and to good occupational medicine practices. Health surveillance for occupationally exposed groups of workers is required under specific health and safety legislation. Workers unexposed to hazard in the workplace cannot be included in health surveillance programme, and declaring these workers unfit for their job is a patent violation of Workers' Statute Law. Psychological disorders should be carefully evaluated in order to clarify their relationship with work. The case of a worker affected with schizophrenia, already reported in the literature, is here re-analysed in order to emphasize these concepts. PMID:17380945

  4. [Mobbing: how to treat it?].

    PubMed

    Schonnebeck, M

    2005-08-01

    Because of its pathogenetic role, the mobbing phenomenon - originally a sociological category- has acquired medical relevance. Before appropriate therapeutic strategies can be agreed upon with the victim, knowledge of the various components of mobbing (system, actors,victims) is required. In difficult cases, the possibility should be investigated whether psychotraumatic or personality-related aspects relating to the victim are responsible for the lack of response. If this is so, the patient should be referred to the appropriate specialists. PMID:16128196

  5. [Mobbing at work].

    PubMed

    Spezzaferro, Ivan

    2005-01-01

    The social psychology has studied the dynamics present in the groups (of work and not) since years 60s: the canalization of the aggressiveness of the group towards some individuals, the conflicts, the theirs administration, the mechanisms of expulsion of the group. The psychology of the work, has studied, those dynamics, in the world of the firms. Lately, the reality of the work has changed. Recently the organizational transformations (fusions) lived in Italy, the flexibility of the work, has caused an exuberance of staff, often not easily administered. The psychologic working violence expanded, generating unemployed persons and becoming a kind of short cut for the firms that, in this way, succeed to resign become inconvenient subordinates. Every day, inside of the firms, a some number of able, capable, responsible and motivated workers bear situations of moral troubles or, as is custom to name them in these years of mobbing. PMID:16436223

  6. Teachers' Perceptions Regarding Mobbing at Schools

    ERIC Educational Resources Information Center

    Gülcan, Murat Gürkan

    2015-01-01

    The aim of the study is to determine whether there are mobbing applications at schools and if so, at which level and between whom. The Mobbing Perception Scale is applied, based on Leymann's (1993), "Mobbing Typology," and developed by Yavuz (2007), to 154 teachers at 5 selected schools in Ankara for the purpose of the study. According…

  7. [Mobbing: a problem in occupational health].

    PubMed

    Rossi, M; D'Andrea, R

    2001-01-01

    Occupational stress may be the cause of psychosomatic and mental disorders. A development of conflicts into a negative direction may trigger a mobbing behaviour at workplace and a mobbing syndrome on the victims. On account of the frequency of mobbing activities at work, it is to assert the need of preventive interventions. PMID:11260971

  8. A Scale of Mobbing Impacts

    ERIC Educational Resources Information Center

    Yaman, Erkan

    2012-01-01

    The aim of this research was to develop the Mobbing Impacts Scale and to examine its validity and reliability analyses. The sample of study consisted of 509 teachers from Sakarya. In this study construct validity, internal consistency, test-retest reliabilities and item analysis of the scale were examined. As a result of factor analysis for…

  9. [Evidence based medicine and mobbing].

    PubMed

    Tomei, G; Cinti, M E; Sancini, A; Cerratti, D; Pimpinella, B; Ciarrocca, M; Tomei, F; Fioravanti, M

    2007-01-01

    The phenomenon of the physical, moral or psychical violence in the working environment, variously indicated as "mobbing", "workplace bullying" or "workplace harassment", is to date object of numerous studies, mostly of epidemiological type, which are yet to clear, in a sufficient way, the aspects of that phenomenon, the possible causes, risk factors, constituent characteristics and consequences. Our search, a systematic review of the existing studies in literature and a meta-analysis of the jobs chosen to such scope, has shown that only a small percentage of the researches conducted on the topic is represented from studies that collected original information on the subject. The results of the meta-analysis show that in the category of the mobbed workers the psychosomatic disturbs, stress, and anxiety are greater than in the group of controls and that the perception of the surrounding environment is more negative in the victims of mobbing compared with the not mobbed workers. The value of such results is reduced by the characteristics and the heterogeneity of the studies. PMID:17886755

  10. Mob grazing for dairy cows

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proponents of mob grazing emphasize increased forage use efficiency and soil improvement by grazing mature forage with stocking densities up to 560,425 lb/ac of beef cattle on small paddocks with rest periods up to 125 days. However, it is unclear if this management technique is appropriate for dair...

  11. Mobbing behaviors encountered by nurse teaching staff.

    PubMed

    Yildirim, Dilek; Yildirim, Aytolan; Timucin, Arzu

    2007-07-01

    The term 'mobbing' is defined as antagonistic behaviors with unethical communication directed systematically at one individual by one or more individuals in the workplace. This cross-sectional and descriptive study was conducted for the purpose of determining the mobbing behaviors encountered by nursing school teaching staff in Turkey, its effect on them, and their responses to them. A large percentage (91%) of the nursing school employees who participated in this study reported that they had encountered mobbing behaviors in the institution where they work and 17% that they had been directly exposed to mobbing in the workplace. The academic staff who had been exposed to mobbing behaviors experienced various physiological, emotional and social reactions. They frequently 'worked harder and [were] more organized and worked very carefully to avoid criticism' to escape from mobbing. In addition, 9% of the participants stated that they 'thought about suicide occasionally'. PMID:17562724

  12. Magister Magistri Lupus? "Mobbing" am Arbeitsplatz Schule (Magister Magistri Lupus? Mobbing in Schools).

    ERIC Educational Resources Information Center

    Rothland, Martin

    2003-01-01

    Sketches the background of mobbing (bullying) in the workplace. Analyzes the school related debate on mobbing. Takes into account the structure and interaction related characteristics of the teaching profession. Asks whether these characteristics can lead to a higher potential for mobbing and how this potential should be assessed. (CAJ)

  13. Mobbing: a problem in flocking and deterrence

    NASA Astrophysics Data System (ADS)

    Elias Tousley, M.; Glaze, Owen; Schall, Anna; Amador Kane, Suzanne

    2010-03-01

    We present experimental and theoretical studies of one type of mobbing behavior in which swarms of prey animals (e.g., tree swallows) harass a predator (e.g., a red-tailed hawk). Empirical field data were collected for tree swallows mobbing a fixed model predator; previous studies have established that this experimental design provokes the same response as actual ``perch-and-wait'' predator behavior. We extended these earlier studies using stereometric video to record the three-dimensional trajectories of prey birds and mobbing cries; we also analyzed single-angle video data taken of crows mobbing red-tailed hawks in flight. Video recordings of red-tailed hawk flight were filmed and analyzed to establish the dynamics of potential predator attacks. The trajectory analysis employed particle-tracking methods and statistical analyses to understand and model the dynamical rules governing this behavior. Swarming behavior during mobbing exhibited a high degree of periodicity and coordination both for fixed predator and in-flight mobbing attacks. The trajectories of individual mobbing birds were analyzed as a random walk superimposed on an approximately elliptical flightpath. Computer simulation studies reproduce several aspects of this behavior, in particular explaining how the mobbing strategy employed by prey birds minimizes the risk of hawk predation while optimizing the frequency of harassing attacks.

  14. Workplace Mobbing: A Discussion for Librarians

    ERIC Educational Resources Information Center

    Hecker, Thomas E.

    2007-01-01

    Workplace mobbing occurs in libraries but is usually unrecognized and unchecked because the phenomenon has not been described and given a name. This discussion provides the library profession with an overview but also with specific background details to assist with recognizing mobbing and preventing severe harm to employees and organizations.

  15. Au Contraire: Gifted in a Flash (Mob)

    ERIC Educational Resources Information Center

    Delisle, James R.

    2012-01-01

    A "flash mob" is defined by Wikipedia as "a large group of people who assemble suddenly in a public place, perform an unusual and pointless act for a brief time, then disperse." Fueled by social media and Smartphones, flash mobs have been used, primarily, as entertaining diversions by addicted techies with (apparently) tons of time on their hands.…

  16. Academic mobbing: hidden health hazard at workplace.

    PubMed

    Khoo, Sb

    2010-01-01

    Academic mobbing is a non-violent, sophisticated, 'ganging up' behaviour adopted by academicians to "wear and tear" a colleague down emotionally through unjustified accusation, humiliation, general harassment and emotional abuse. These are directed at the target under a veil of lies and justifications so that they are "hidden" to others and difficult to prove. Bullies use mobbing activities to hide their own weaknesses and incompetence. Targets selected are often intelligent, innovative high achievers, with good integrity and principles. Mobbing activities appear trivial and innocuous on its own but the frequency and pattern of their occurrence over long period of time indicates an aggressive manipulation to "eliminate" the target. Mobbing activities typically progress through five stereotypical phases that begins with an unsolved minor conflict between two workers and ultimately escalates into a senseless mobbing whereby the target is stigmatized and victimized to justify the behaviours of the bullies. The result is always physical, mental, social distress or illness and, most often, expulsion of target from the workplace. Organizations are subjected to great financial loss, loss of key workers and a tarnished public image and reputation. Public awareness, education, effective counselling, establishment of anti-bullying policies and legislations at all levels are necessary to curb academic mobbing. General practitioners (GPs) play an important role in supporting patients subjected to mental and physical health injury caused by workplace bullying and mobbing. PMID:25606190

  17. [Mobbing as the syndrome of destructive professiogenesis].

    PubMed

    Sidorov, P I

    2013-01-01

    Mobbing has entered reference books as the syndrome including harassment and insult of employees in the workplaces for the purpose of constraint for dismissal. In the framework of the synergetic methodology, fractal dynamics of mobbing sociogenesis, psychogenesis and somatogenesis have been separated. Approaches to early diagnostics and prevention in the framework of the strategies of adaptive professiogenesis formation have been explained. A system approach to development of preventive-correctional and treatment-rehabilitation medicopsychosocial programs has been proposed. PMID:24000726

  18. Suicide risk and exposure to mobbing.

    PubMed

    Pompili, Maurizio; Lester, David; Innamorati, Marco; De Pisa, Eleonora; Iliceto, Paolo; Puccinno, Marianna; Fiori Nastro, Paolo; Tatarelli, Roberto; Girardi, Paolo

    2008-01-01

    The aim of this study was to study suicide risk in subjects exposed to mobbing, that is, systematic psychological harassment in the workplace. Such psychological harassment, unique to the workplace, threatens both the emotional well-being and professional ability of its victims. The items of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) that assess suicide risk were studied in 102 individuals who were exposed to mobbing. The results indicated that individuals exposed to mobbing had clear differences on the MMPI-2 from normative samples. In addition, those who appeared to be at risk for suicide differed in their scores from those not at risk. Implications for psychopathology and suicide preventions are discussed. PMID:18957741

  19. [Questionnaire for the mobbing risk: CDL2.0].

    PubMed

    Gilioli, R; Cassitto, M G; Campanini, P; Punzi, S; Consonni, D; Rengo, C; Fattorini, E; Foá, V

    2005-01-01

    The aim of the study is to develop and validate a questionnaire able to evaluate the risk of mobbing at the workplace. A multiple-choice questionnaire has been developed which contains, among the different items, only one revealing a mobbing situation. The questionnaire has been administered to two groups (group A--243 subjects in a mobbing situation and group B--63 subjects without exposure to mobbing) and the differences in the scores obtained have been analysed. The questionnaire has proved to be valid and reliable. The results show that the presence of five mobbing actions is sufficient to define the workplace situation as potentially at risk for mobbing. The study reveals some limits in the selection of the two samples thus needing some adjustment. However, the questionnaire, also in the present form, can be considered a tool able to detect the mobbing situations. PMID:16240603

  20. Mobbing Behaviour: Victims and the Affected

    ERIC Educational Resources Information Center

    Erturk, Abbas

    2013-01-01

    The purpose of this research was to identify the level of mobbing behaviour faced by teachers and managers working in primary schools, their responses to such behaviour and the difference in these responses according to the gender variable. The sample of the research consists of a total of 1,316 teachers and managers including 691 men and 625…

  1. Mobbing: Workplace Violence in the Academy

    ERIC Educational Resources Information Center

    Keim, Jeanmarie; McDermott, J. Cynthia

    2010-01-01

    Incidents of workplace violence are becoming all too common at colleges and universities. Generally, one thinks of shootings and assaults in relation to campus workplace violence. However, mobbing and bullying of faculty by other faculty are types of workplace violence that, while very common, are rarely discussed or reported. This article raises…

  2. Crystal Structures, Stabilities, Electronic Properties, and Hardness of MoB2: First-Principles Calculations.

    PubMed

    Ding, Li-Ping; Shao, Peng; Zhang, Fang-Hui; Lu, Cheng; Ding, Lei; Ning, Shu Ya; Huang, Xiao Fen

    2016-07-18

    On the basis of the first-principles techniques, we perform the structure prediction for MoB2. Accordingly, a new ground-state crystal structure WB2 (P63/mmc, 2 fu/cell) is uncovered. The experimental synthesized rhombohedral R3̅m and hexagonal AlB2, as well as theoretical predicted RuB2 structures, are no longer the most favorite structures. By analyzing the elastic constants, formation enthalpies, and phonon dispersion, we find that the WB2 phase is thermodynamically and mechanically stable. The high bulk modulus B, shear modulus G, low Poisson's ratio ν, and small B/G ratio are benefit to its low compressibility. When the pressure is 10 GPa, a phase transition is observed between the WB2-MoB2 and the rhombohedral R3̅m MoB2 phases. By analyzing the density of states and electron density, we find that the strong covalent is formed in MoB2 compounds, which contributes a great deal to its low compressibility. Furthermore, the low compressibility is also correlated with the local buckled structure. PMID:27387577

  3. Millimeter wave radiometer installation in Río Gallegos, southern Argentina

    NASA Astrophysics Data System (ADS)

    Orte, P. F.; Salvador, J.; Wolfram, E.; D'Elia, R.; Nagahama, T.; Kojima, Y.; Tanada, R.; Kuwahara, T.; Morihira, A.; Quel, E.; Mizuno, A.

    2011-05-01

    With the aim of contribution to the study of atmospheric ozone layer, a new sensitive radiometer for atmospheric minor constituents has been installed in the Observatorio Atmosférico de la Patagonia Austral, División LIDAR, CEILAP (CITEDEF-CONICET), in October 2010. This observatory is established in the city of Rio Gallegos (51° 36' S, 69° 19' W), Argentina, close to the spring ozone hole. The millimeter wave radiometer was developed in STEL (Solar Terrestrial Environment Laboratory), Nagoya University, Japan. This passive remote sensing instrument is able to measure the ozone (O3) amount in the high stratosphere and mesosphere continuously and automatically with a high time resolution. The millimeter wave radiometer ozone profiles will be supplemented with the ozone profiles obtained from the DIAL system existent in the observatory. The millimeter wave radiometer is based on the spectral signal detection from the atmosphere due to the molecular rotational transition of molecules under study. The operation is based on a superheterodyne system which uses a Superconductor-Insulator-Superconductor (SIS) mixer receiver operating at 203.6GHz. The SIS mixer junction consists of a sandwich structure of Nb/AlOx/Nb, and is cooled to 4.2K with a closed cycle He-gas refrigerator. Two additional heterodyne-mixed stages are realized with the aim to shift the measured spectral line until a frequency around of 500 MHz. A FFT (Fast Fourier Transform) spectrometer system is used as a back end. The aims of this work are to show the potential of the millimeter wave radiometer installed in the subpolar latitudes close to the polar ozone hole and to present the preliminary result of the first measurements.

  4. Psychological Parameters for Crowd Simulation: From Audiences to Mobs.

    PubMed

    Durupinar, Funda; Gudukbay, Ugur; Aman, Aytek; Badler, Norman I

    2016-09-01

    In the social psychology literature, crowds are classified as audiences and mobs. Audiences are passive crowds, whereas mobs are active crowds with emotional, irrational and seemingly homogeneous behavior. In this study, we aim to create a system that enables the specification of different crowd types ranging from audiences to mobs. In order to achieve this goal we parametrize the common properties of mobs to create collective misbehavior. Because mobs are characterized by emotionality, we describe a framework that associates psychological components with individual agents comprising a crowd and yields emergent behaviors in the crowd as a whole. To explore the effectiveness of our framework we demonstrate two scenarios simulating the behavior of distinct mob types. PMID:26595922

  5. Intercomparison of Ozone and Temperature Profiles During OZITOS+ 2014 Campaign in Río Gallegos, Argentina

    NASA Astrophysics Data System (ADS)

    Salvador, Jacobo; Wolfram, Elian; Orte, Facundo; D'Elia, Raúl; Quiroga, Jonathan; Quel, Eduardo; Zamorano, Felix; Pérez, Raúl; Villa, Israel; Oyama, Hirofumi; Mizuno, Akira

    2016-06-01

    In the framework of SAVER-Net project, the OZone profIle aT Río GallegOS (OZITOS+) campaign was held in the city of Río Gallegos, Argentina (51.5 S; 69.1 W). This experiment was conducted on October 14 -18, 2014 and its main goal was to compare the ozone and temperature profiles using three different measurement techniques such as Differential Absorption Lidar (DIAL), ozonesonde and Millimeter Wave Radiometer (MWR). Also other ground-based and satellite-based instruments were included in the experiment but in this work we only present preliminary results from ground-based instruments deployed in the site. The DIAL instrument is part of Network Data for Atmospheric Composition Change (NDACC) network, and the usual protocols of quality assurance imposed for the network involve regular validation/comparisons experiments. The lidar ozone profiles measured with the lidar are compared with ozone profiles obtained with independent techniques, usually with higher or same resolution as lidar. The experiment are made collocated spatial and temporally. For that reason the Chilean team joined to Japanese and Argentine team at Río Gallegos to develop the experiment. On October 2014, the Río Gallegos Observatory station was inside the polar vortex during first two weeks and after that polar vortex have moved far away from Río Gallegos during the 3rd week of October, when the intercomparison campaign was held. In this paper we are present a preliminary results of the campaign, computing the ozone and temperature profiles from DIAL with ozonesondes and MWR.

  6. Workplace mobbing and effects on workers' health.

    PubMed

    Meseguer de Pedro, Mariano; Soler Sánchez, María Isabel; Sáez Navarro, María Concepción; García Izquierdo, Mariano

    2008-05-01

    In this work, we analyze various consequences of the phenomenon of mobbing on the health of a work sector with special characteristics: the agro fruit sector. For this purpose, we collected data from a sample of 396 workers (61 men and 331 women) belonging to this sector in the Region of Murcia (Spain). A questionnaire with the following measurement instruments was administered: a Spanish adaptation of the revised Negative Acts Questionnaire (Sáez, García, & Llor, 2003), the Psychosomatic Problems Questionnaire (Hock, 1988), and a measure of absenteeism. The results revealed a significant and positive relation between workplace mobbing and psychosomatic symptoms, but not with absenteeism. The implications of the results for future research are discussed. PMID:18630663

  7. [Mobbing in nursing. A pilot study].

    PubMed

    Fornés Vives, Joana; Reinés Femenia, Joan; Sureda García, Catalina

    2004-09-01

    While planning to help shed light on the phenomenon of mobbing in the work place and to develop an instrument by which to measure it, the authors carried out a pilot study in which 160 persons from varying professional classes and autonomous communities in Spain participated, 65 of whom were nurses whose ages lie between 20 and 48 years, with a medium age of 33.98. By means of a factorial analysis, the authors discovered that the most common mobbing practices are grouped in a set of eight factors; these eight factors cover 74.17% of all the various factors. The two most significant factors refer to behaviors which can be considered to be personal humiliation and professional discredit. The most common mobbing practice, according to the overall findings of this study group, consists in providing contradictory information to the victim (19.4% once or more times per week), while in nursing, this practice consists of exposing the victim to criticism by the group (50%). PMID:15526573

  8. An Economic Model of Workplace Mobbing in Academe

    ERIC Educational Resources Information Center

    Faria, Joao Ricardo; Mixon, Franklin G., Jr.; Salter, Sean P.

    2012-01-01

    Workplace bullying or mobbing can be defined as the infliction of various forms of abuse (e.g., verbal, emotional, psychological) against a colleague or subordinate by one or more other members of a workplace. Even in the presence of academic tenure, workplace mobbing remains a prevalent issue in academe. This study develops an economic model that…

  9. Personality and psychopathological profiles in individuals exposed to mobbing.

    PubMed

    Girardi, Paolo; Monaco, Edoardo; Prestigiacomo, Claudio; Talamo, Alessandra; Ruberto, Amedeo; Tatarelli, Roberto

    2007-01-01

    Increasingly, mental health and medical professionals have been asked to assess claims of psychological harm arising from harassment at the workplace, or "mobbing." This study assessed the personality and psychopathological profiles of 146 individuals exposed to mobbing using validity, clinical, and content scales of the Minnesota Multiphasic Personality Inventory 2. Profiles and factor analyses were obtained. Two major dimensions emerged among those exposed to mobbing: (a) depressed mood, difficulty in making decisions, change-related anguish, and passive-aggressive traits (b) somatic symptoms, and need for attention and affection. This cross-sectional pilot study provides evidence that personality profiles of mobbing victims and psychological damage resulting from mobbing may be evaluated using standardized assessments, though a longitudinal study is needed to delineate cause-and-effect relationships. PMID:17479554

  10. [Psychosocial risk factors at work as predictors of mobbing].

    PubMed

    Meseguer de Pedro, Mariano; Soler Sánchez, María I; García-Izquierdo, Mariano; Sáez Navarro, M C; Sánchez Meca, Julio

    2007-05-01

    This work analyses the way in which various psychosocial risk indicators may predict mobbing. A sample of 638 workers, 168 men and 470 women, from the fruit-and-vegetable sector was evaluated. An anonymous questionnaire was administered to all employees who were present on the evaluation days in the companies comprising the study. After analysing the data obtained with the mobbing questionnaire NAQ-RE (Sáez, García-Izquierdo, and Llor, 2003) and with the psychosocial risk factors evaluation method of the INSHT (Martín and Pérez, 1997), using canonical regression, we found that several psychosocial factors such as role definition, mental workload, interest in the workers, and supervision / participation predict two types of mobbing: personal mobbing and work-performance-related mobbing. PMID:17425890

  11. Future climate scenarios and rainfall--runoff modelling in the Upper Gallego catchment (Spain).

    PubMed

    Bürger, C M; Kolditz, O; Fowler, H J; Blenkinsop, S

    2007-08-01

    Global climate change may have large impacts on water supplies, drought or flood frequencies and magnitudes in local and regional hydrologic systems. Water authorities therefore rely on computer models for quantitative impact prediction. In this study we present kernel-based learning machine river flow models for the Upper Gallego catchment of the Ebro basin. Different learning machines were calibrated using daily gauge data. The models posed two major challenges: (1) estimation of the rainfall-runoff transfer function from the available time series is complicated by anthropogenic regulation and mountainous terrain and (2) the river flow model is weak when only climate data are used, but additional antecedent flow data seemed to lead to delayed peak flow estimation. These types of models, together with the presented downscaled climate scenarios, can be used for climate change impact assessment in the Gallego, which is important for the future management of the system. PMID:17428594

  12. Mobbing in the Schools. Scandinavian Initiatives in the Prevention and Reduction of Group Violence among Children.

    ERIC Educational Resources Information Center

    Juul, Kristen D.

    The paper defines the concept of mobbing and notes alternate terms such as bullying, scapegoating, and group violence or aggression. Scandinavian research and literature on mobbing is analyzed, especially as it relates to the incidence of mobbing and characteristics of aggressor and victim. Intervention efforts are described, such as individual…

  13. Those Mean Girls and Their Friends: Bullying and Mob Rule in the Academy

    ERIC Educational Resources Information Center

    Dentith, Audrey M.; Wright, Robin Redmon; Coryell, Joellen

    2015-01-01

    This article highlights the stories and experiences of three White women who were victims of bullying and mobbing in academic settings. Related literature grounds their experiences and offers insights related to the phenomena including definitions of mobbing and bullying, characteristics of bullies, the prevalence of bullying and mobbing, and the…

  14. Assessment of Turkish junior male physicians’ exposure to mobbing behavior

    PubMed Central

    Sahin, Bayram; Cetin, Mehmet; Cimen, Mesut; Yildiran, Nuri

    2012-01-01

    Aim To determine the extent of Turkish junior male physicians’ exposure to mobbing behavior and its correlation with physicians' characteristics. Methods The study included physicians recruited for compulsory military service in April 2009. No sampling method was used, questionnaires were delivered to all physicians, and 278 of 292 (95%) questionnaires were returned. We used Leymann Inventory of Psychological Terror including 45 items for data collection and structural equation model for data analysis. Results A total of 87.7% of physicians experienced mobbing behavior. Physicians who worked more than 40 hours a week, single physicians, physicians working in university hospitals and private hospitals, and physicians who did not have occupational commitment were more exposed to mobbing (P < 0.05). Mobbing was not associated with specialty status, service period, age, and personality variables (P > 0.05). All goodness-of- fit indices of the model were acceptable (χ2 = 1.449, normed fit index = 0.955, Tucker Lewis index = 0.980, comparative fit index = 0.985, and root mean square error of approximation = 0.040). Conclusions Workplace mobbing is a critical problem for junior male physicians in Turkey. We suggest an introduction of a reporting system and education activities for physicians in high-risk groups. PMID:22911529

  15. You mob my owl, I'll mob yours: birds play tit-for-tat game.

    PubMed

    Krama, Tatjana; Vrublevska, Jolanta; Freeberg, Todd M; Kullberg, Cecilia; Rantala, Markus J; Krams, Indrikis

    2012-01-01

    Reciprocity is fundamental to cooperative behaviour and has been verified in theoretical models. However, there is still limited experimental evidence for reciprocity in non-primate species. Our results more decisively clarify that reciprocity with a tit-for-tat enforcement strategy can occur among breeding pied flycatchers Ficedula hypoleuca separate from considerations of byproduct mutualism. Breeding pairs living in close proximity (20-24 m) did exhibit byproduct mutualism and always assisted in mobbing regardless of their neighbours' prior actions. However, breeding pairs with distant neighbours (69-84 m) either assisted or refused to assist in mobbing a predatory owl based on whether or not the distant pair had previously helped them in their own nest defense against the predator. Clearly, these birds are aware of their specific spatial security context, remember their neighbours' prior behaviour, and choose a situation-specific strategic course of action, which could promote their longer-term security, a capacity previously thought unique to primates. PMID:23150772

  16. Mobbing Experiences of Instructors: Causes, Results, and Solution Suggestions

    ERIC Educational Resources Information Center

    Celep, Cevat; Konakli, Tugba

    2013-01-01

    In this study, it was aimed to investigate possible mobbing problems in universities, their causes and results, and to attract attention to precautions that can be taken. Phenomenology as one of the qualitative research methods was used in the study. Sample group of the study was selected through the criteria sampling method and eight instructors…

  17. The Validity and Reliability of the Mobbing Scale (MS)

    ERIC Educational Resources Information Center

    Yaman, Erkan

    2009-01-01

    The aim of this research is to develop the Mobbing Scale and examine its validity and reliability. The sample of the study consisted of 515 persons from Sakarya and Bursa. In this study, construct validity, internal consistency, test-retest reliability, and item analysis of the scale were examined. As a result of factor analysis for construct…

  18. Treatment of Mobbing in School: Principles for and the Results of the Work of an Anti Mobbing Group

    ERIC Educational Resources Information Center

    Pikas, Anatol

    1975-01-01

    Article attempted to define the concept of mobbing and to develop principles of treatment in connection with cases which really occur, and to use the work in a regular university course providing students with successful personal therapeutic experiences. (Author/RK)

  19. Why mob? Reassessing the costs and benefits of primate predator harassment.

    PubMed

    Crofoot, Margaret C

    2012-01-01

    While some primate species attempt to avoid predators by fleeing, hiding or producing alarm calls, others actually approach, harass and sometimes attack potential threats, a behavior known as 'mobbing'. Why individuals risk their safety to mob potential predators remains poorly understood. Here, I review reports of predator harassment by primates to (1) determine the distribution of this behavior across taxa, (2) assess what is known about the costs of mobbing, and (3) evaluate hypotheses about its function. Mobbing is taxonomically widespread and is used against a wide range of predator species. However, inconsistent use of the term 'mobbing' within the primate literature, the lack of systematic studies of primate mobbing, and the likelihood of systematic biases in the existing data pose significant obstacles to understanding this puzzling behavior. Although difficult to quantify, the costs associated with harassing predators appear nontrivial. Many benefits that have been proposed to explain mobbing in birds may also be important in primate systems. There are puzzling aspects of primate mobbing, however, that existing hypotheses cannot explain. Future research should consider the within-group signaling potential of this costly behavior, as well as the ability of behavioral syndromes to explain the distribution of mobbing in primates. PMID:23363587

  20. [Mobbing in the workplace: new aspects of an old phenomenon].

    PubMed

    Cassitto, M G

    2001-01-01

    In the last ten years there has been increasing concern about the well known old practice of victimization at work, which in recent years has emerged with new characteristics, aims and consequences and is now generally referred to as mobbing behavior. This increased attention seems to be due to increased awareness of individual rights and respect for the dignity of self and others, and to the new economy emphasis on flexibility and reorganizational needs. Moral violence should not be confused with the normal competition and conflicts encountered in work place. Mobbing can be originated by traditional causes such as eliminating an undesired individual or by a precise corporate strategy aimed at reducing the workforce organizations. Mobbing has been recognized as a significant source of individual discomfort and subsequently illness. Lacking specific diagnostic criteria, Post-traumatic Stress Disorder and Adjustment Disorder have been adopted from the international classification of mental diseases (DSM). However, interviews and personality screening highlight specific differences compared with other psychic disorders, not in symptom severity but in the induced loss of parameters which guarantee individual consistency in life, namely self-esteem, event intelligibility, cause-effect relationship, confidence in others, which lead to role and status depletion and eventually acquisition of an invalid personality. The human and economic cost of antisocial behavior at work, with illness, absenteeism and finally unemployment is extremely high for the victims and their families, employers and society. Mobbing control is not only a prevention target but a moral obligation. It should be recognized that interpersonal correctness, respect of individual skills and dignity do not interfere with group efficiency, reorganization, staff reduction and relocation and that these aims can be reached without destroying an individual. PMID:11367823

  1. Vitamin D synthesis measured with a multiband filter radiometer in Río Gallegos, Argentina

    NASA Astrophysics Data System (ADS)

    Orte, Facundo; Wolfram, Elian; Salvador, Jacobo; D'Elia, Raúl; Bulnes, Daniela; Leme, N. Paes; Quel, Eduardo

    2013-05-01

    Vitamin D plays an important role in human health. Vitamin D production from the sun is affected by UVB solar radiation. This paper presents a simple method for retrieving vitamin D-weighted UV by using a multiband filter radiometer GUV-541 installed at the Atmospheric Observatory of Southern Patagonia (OAPA) (51 ° 33' S, 69° 19' W), Río Gallegos. The methodology used combines irradiance measurements from a multiband filter radiometer with spectral irradiance modeled by the SOS radiative transfer code (developed by Lille University of Science and Technology (USTL)). The spectrum modeled is weighted with vitamin D action spectra published by the International Commission on Illumination (CIE), which describes the relative effectiveness of different wavelengths in the generation of this particular biological response. This method is validated using the vitamin D-weighted UV derived from a Brewer MKIII spectrophotometer (SN 124) belonging to the National Institute for Spatial Research (INPE), Brazil, which is able to measure solar spectra between 290 and 325nm. The method presents a good correlation between the two independent instruments. This procedure increases the instrumental capabilities of the multiband filter radiometer. Moreover, it evaluates the annual variation of vitamin D-weighted UV doses from exposure to ultraviolet radiation. These values are likely to be lower than suitable levels of vitamin D during winter and part of spring and autumn at these latitudes.

  2. NCP1/AtMOB1A Plays Key Roles in Auxin-Mediated Arabidopsis Development

    PubMed Central

    Song, Lizhen; Wang, Yanli; Cheng, Youfa

    2016-01-01

    MOB1 protein is a core component of the Hippo signaling pathway in animals where it is involved in controlling tissue growth and tumor suppression. Plant MOB1 proteins display high sequence homology to animal MOB1 proteins, but little is known regarding their role in plant growth and development. Herein we report the critical roles of Arabidopsis MOB1 (AtMOB1A) in auxin-mediated development in Arabidopsis. We found that loss-of-function mutations in AtMOB1A completely eliminated the formation of cotyledons when combined with mutations in PINOID (PID), which encodes a Ser/Thr protein kinase that participates in auxin signaling and transport. We showed that atmob1a was fully rescued by its Drosophila counterpart, suggesting functional conservation. The atmob1a pid double mutants phenocopied several well-characterized mutant combinations that are defective in auxin biosynthesis or transport. Moreover, we demonstrated that atmob1a greatly enhanced several other known auxin mutants, suggesting that AtMOB1A plays a key role in auxin-mediated plant development. The atmob1a single mutant displayed defects in early embryogenesis and had shorter root and smaller flowers than wild type plants. AtMOB1A is uniformly expressed in embryos and suspensor cells during embryogenesis, consistent with its role in embryo development. AtMOB1A protein is localized to nucleus, cytoplasm, and associated to plasma membrane, suggesting that it plays roles in these subcellular localizations. Furthermore, we showed that disruption of AtMOB1A led to a reduced sensitivity to exogenous auxin. Our results demonstrated that AtMOB1A plays an important role in Arabidopsis development by promoting auxin signaling. PMID:26942722

  3. NCP1/AtMOB1A Plays Key Roles in Auxin-Mediated Arabidopsis Development.

    PubMed

    Cui, Xiaona; Guo, Zhiai; Song, Lizhen; Wang, Yanli; Cheng, Youfa

    2016-03-01

    MOB1 protein is a core component of the Hippo signaling pathway in animals where it is involved in controlling tissue growth and tumor suppression. Plant MOB1 proteins display high sequence homology to animal MOB1 proteins, but little is known regarding their role in plant growth and development. Herein we report the critical roles of Arabidopsis MOB1 (AtMOB1A) in auxin-mediated development in Arabidopsis. We found that loss-of-function mutations in AtMOB1A completely eliminated the formation of cotyledons when combined with mutations in PINOID (PID), which encodes a Ser/Thr protein kinase that participates in auxin signaling and transport. We showed that atmob1a was fully rescued by its Drosophila counterpart, suggesting functional conservation. The atmob1a pid double mutants phenocopied several well-characterized mutant combinations that are defective in auxin biosynthesis or transport. Moreover, we demonstrated that atmob1a greatly enhanced several other known auxin mutants, suggesting that AtMOB1A plays a key role in auxin-mediated plant development. The atmob1a single mutant displayed defects in early embryogenesis and had shorter root and smaller flowers than wild type plants. AtMOB1A is uniformly expressed in embryos and suspensor cells during embryogenesis, consistent with its role in embryo development. AtMOB1A protein is localized to nucleus, cytoplasm, and associated to plasma membrane, suggesting that it plays roles in these subcellular localizations. Furthermore, we showed that disruption of AtMOB1A led to a reduced sensitivity to exogenous auxin. Our results demonstrated that AtMOB1A plays an important role in Arabidopsis development by promoting auxin signaling. PMID:26942722

  4. 78 FR 29120 - Notice of Intent To Prepare an Environmental Impact Statement for the Main Operating Base 2 (MOB...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-17

    ... of Intent To Prepare an Environmental Impact Statement for the Main Operating Base 2 (MOB-2) for the... prepare an Environmental Impact Statement (EIS) for the Main Operating Base 2 (MOB-2) for the beddown of... the MOB-2 at existing Air National Guard (ANG) installations within the continental United States....

  5. Structural basis for autoinhibition and its relief of MOB1 in the Hippo pathway

    PubMed Central

    Kim, Sun-Yong; Tachioka, Yuka; Mori, Tomoyuki; Hakoshima, Toshio

    2016-01-01

    MOB1 protein is a key regulator of large tumor suppressor 1/2 (LATS1/2) kinases in the Hippo pathway. MOB1 is present in an autoinhibited form and is activated by MST1/2-mediated phosphorylation, although the precise mechanisms responsible for autoinhibition and activation are unknown due to lack of an autoinhibited MOB1 structure. Here, we report on the crystal structure of full-length MOB1B in the autoinhibited form and a complex between the MOB1B core domain and the N-terminal regulation (NTR) domain of LATS1. The structure of full-length MOB1B shows that the N-terminal extension forms a short β-strand, the SN strand, followed by a long conformationally flexible positively-charged linker and α-helix, the Switch helix, which blocks the LATS1 binding surface of MOB1B. The Switch helix is stabilized by β-sheet formation of the SN strand with the S2 strand of the MOB1 core domain. Phosphorylation of Thr12 and Thr35 residues structurally accelerates dissociation of the Switch helix from the LATS1-binding surface by the “pull-the-string” mechanism, thereby enabling LATS1 binding. PMID:27335147

  6. Structural basis for autoinhibition and its relief of MOB1 in the Hippo pathway.

    PubMed

    Kim, Sun-Yong; Tachioka, Yuka; Mori, Tomoyuki; Hakoshima, Toshio

    2016-01-01

    MOB1 protein is a key regulator of large tumor suppressor 1/2 (LATS1/2) kinases in the Hippo pathway. MOB1 is present in an autoinhibited form and is activated by MST1/2-mediated phosphorylation, although the precise mechanisms responsible for autoinhibition and activation are unknown due to lack of an autoinhibited MOB1 structure. Here, we report on the crystal structure of full-length MOB1B in the autoinhibited form and a complex between the MOB1B core domain and the N-terminal regulation (NTR) domain of LATS1. The structure of full-length MOB1B shows that the N-terminal extension forms a short β-strand, the SN strand, followed by a long conformationally flexible positively-charged linker and α-helix, the Switch helix, which blocks the LATS1 binding surface of MOB1B. The Switch helix is stabilized by β-sheet formation of the SN strand with the S2 strand of the MOB1 core domain. Phosphorylation of Thr12 and Thr35 residues structurally accelerates dissociation of the Switch helix from the LATS1-binding surface by the "pull-the-string" mechanism, thereby enabling LATS1 binding. PMID:27335147

  7. Perception of Faculty Members Exposed to Mobbing about the Organizational Culture and Climate

    ERIC Educational Resources Information Center

    Yaman, Erkan

    2010-01-01

    The present research aimed to investigate non-ethical behaviors and mobbing to which academic staff in universities are subjected. Twelve academic staff who were subjected to mobbing in universities in Turkey were interviewed. The research was formed in a qualitative design. Results show that the metaphors that the instructors use to liken their…

  8. Climatic implications of correlated upper Pleistocene glacial and fluvial deposits on the Cinca and Gallego rivers, NE Spain

    SciTech Connect

    Lewis, Claudia J; Mcdonald, Eric; Sancho, Carlos; Pena, Jose- Luis

    2008-01-01

    We correlate Upper Pleistocene glacial and fluvial deposits of the Cinca and Gallego River valleys (south central Pyrenees and Ebro basin, Spain) using geomorphic position, luminescence dates, and time-related trends in soil development. The ages obtained from glacial deposits indicate glacial periods at 85 {+-} 5 ka, 64 {+-} 11 ka, and 36 {+-} 3 ka (from glacial till) and 20 {+-} 3 ka (from loess). The fluvial drainage system, fed by glaciers in the headwaters, developed extensive terrace systems in the Cinca River valley at 178 {+-} 21 ka, 97 {+-} 16 ka, 61 {+-} 4 ka, 47 {+-} 4 ka, and 11 {+-} 1 ka, and in the Gallego River valley at 151 {+-} 11 ka, 68 {+-} 7 ka, and 45 {+-} 3 ka. The times of maximum geomorphic activity related to cold phases coincide with Late Pleistocene marine isotope stages and heinrich events. The maximum extent of glaciers during the last glacial occurred at 64 {+-} 11 ka, and the terraces correlated with this glacial phase are the most extensive in both the Cinca (61 {+-} 4 ka) and Gallego (68 {+-} 7 ka) valleys, indicating a strong increase in fluvial discharge and availability of sediments related to the transition to deglaciation. The global Last Glacial Maximum is scarcely represented in the south central Pyrenees owing to dominantly dry conditions at that time. Precipitation must be controlled by the position of the Iberian Peninsula with respect to the North Atlantic atmospheric circulation system. The glacial systems and the associated fluvial dynamic seem sensitive to (1) global climate changes controlled by insolation, (2) North Atlantic thermohaline circulation influenced by freshwater pulses into the North Atlantic, and (3) anomalies in atmospheric circulation in the North Atlantic controlling precipitation on the Iberian peninsula. The model of glacial and fluvial evolution during the Late Pleistocene in northern Spain could be extrapolated to other glaciated mountainous areas in southern Europe.

  9. Stress and nurses' horizontal mobbing: moderating effects of group identity and group support.

    PubMed

    Topa, Gabriela; Moriano, Juan A

    2013-01-01

    Horizontal mobbing is a process of systematic and repeated aggression towards a worker by coworkers. Among others, stress has been pointed out as one of the antecedents that favors the onset of horizontal mobbing, whereas group support to the target could act as a buffer. Moreover, the social identity approach emphasizes that group identity is an antecedent of group support. This study explores the interaction of group support and group identity in the explanation of horizontal mobbing in a sample (N = 388) of registered nurses and licensed practical nurses employed at two large hospitals in Madrid and Navarre (Spain). The results show that stress is positively associated to horizontal mobbing, whereas group support and group identity were negative predictors of horizontal mobbing. Furthermore, the combination of low group identity and low group support precipitated HM among nurses. PMID:23664419

  10. Novel mobbing strategies of a fish population against a sessile annelid predator.

    PubMed

    Lachat, Jose; Haag-Wackernagel, Daniel

    2016-01-01

    When searching for food, foraging fishes expose themselves to hidden predators. The strategies that maximize the survival of foraging fishes are not well understood. Here, we describe a novel type of mobbing behaviour displayed by foraging Scolopsis affinis. The fish direct sharp water jets towards the hidden sessile annelid predator Eunice aphroditois (Bobbit worm). We recognized two different behavioural roles for mobbers (i.e., initiator and subsequent participants). The first individual to exhibit behaviour indicating the discovery of the Bobbit directed, absolutely and per time unit, more water jets than the subsequent individuals that joined the mobbing. We found evidence that the mobbing impacted the behaviour of the Bobbit, e.g., by inducing retraction. S. affinis individuals either mob alone or form mobbing groups. We speculate that this behaviour may provide social benefits for its conspecifics by securing foraging territories for S. affinis. Our results reveal a sophisticated and complex behavioural strategy to protect against a hidden predator. PMID:27615670

  11. [Mobbing in nursing: a survey results in Tuscany].

    PubMed

    Bromo, Cristina; Bartolucci, Giorgio

    2005-01-01

    This article will present mobbing in its different aspects and consequences with reference to its manifestations in sanitarian organizations and in nursing. It springs out from wish to inquire into a phenomenon which generates uncomfortableness and embarrassment; it springs out from wish to know what it is and because it frights; it springs out from wish to understand it, to defend oneselves against it and to keep out it. It springs out from curiosity to know if it is present in nursing and eventually how much is its entity. The cognitive research takes place in a Tuscan Sanitary Factory. PMID:16436224

  12. Alfalfa Mob1-like proteins are involved in cell proliferation and are localized in the cell division plane during cytokinesis

    SciTech Connect

    Citterio, Sandra; Piatti, Simonetta; Albertini, Emidio; Aina, Roberta; Varotto, Serena; Barcaccia, Gianni . E-mail: gianni.barcaccia@unipd.it

    2006-04-15

    Mps-one-binder (Mob) proteins play a crucial role in yeast cytokinesis. After cloning two Mob1-like genes, MsMob1-A and MsMob1-B from alfalfa (Medicago sativa L.) we show that, although they are constitutively expressed in roots, stems, leaves, flowers and pods, their transcripts and proteins are mostly produced in actively proliferating tissues. A polyclonal antibody specifically raised against MsMob1 proteins was used for immunolocalization studies in synchronized root tip cells. The subcellular localization of MsMob1-like proteins is demonstrated to be cell cycle-regulated. Cytoplasmic localization is faint and diffused during G{sub 1} and S. It becomes concentrated in punctuate and fibrillar structures in G{sub 2} as well as M phase. At the stage of cytokinesis, the protein is found at the emerging cell plate marking the progressive formation of the septum. Mob1 proteins partially co-localize with microtubules structures functionally related to the spindles and important for cytokinesis in eukaryotic cells. The MsMob1 expression cannot rescue the lethality of the yeast mob1 mutant, suggesting that interaction of Mob1 proteins with their effectors may be species-specific. Localization of Mob1 proteins in the inner layer of the root cap indicates an additional function for this class of proteins in plants, which is likely related to the onset of programmed cell death.

  13. The Effect of Assertiveness Training on the Mobbing That Nurses Experience.

    PubMed

    Karakaş, Sibel Asi; Okanli, Ayşe

    2015-10-01

    This research was designed to determine the impact of assertiveness training on the mobbing experience of nurses. This study was conducted in two phases. In the first phase, 218 nurses completed the mobbing scale; the education group consisted of 38 nurses who received a score at or above 204 points. A total of 180 nurses were excluded from the education group because they received less than 204 points. The study was conducted with 30 nurses because 8 nurses did not agree to participate in the study. The 30 nurses received the assertiveness training program. Six months after training, the nurses completed the mobbing scale and Rathus Assertiveness Inventory (RAI) again. The assertiveness training positively affected the assertiveness and mobbing scores (p = .000). After the training, the assertiveness scores increased and the mobbing condition score decreased (p < .01). Assertiveness training is an effective method for decreasing mobbing. In line with these results, training programs, which support nurses' personal development by providing counseling and support to nurse victims of mobbing, are recommended. PMID:26242741

  14. Concerted action of NIC relaxase and auxiliary protein MobC in RA3 plasmid conjugation.

    PubMed

    Godziszewska, Jolanta; Moncalián, Gabriel; Cabezas, Matilde; Bartosik, Aneta A; de la Cruz, Fernando; Jagura-Burdzy, Grazyna

    2016-08-01

    Conjugative transfer of the broad-host-range RA3 plasmid, the archetype of the IncU group, relies on the relaxase NIC that belongs to the as yet uncharacterized MOBP4 subfamily. NIC contains the signature motifs of HUH relaxases involved in Tyr nucleophilic attack. However, it differs in the residue involved in His activation for cation coordination and was shown here to have altered divalent cation requirements. NIC is encoded in the mobC-nic operon preceded directly by oriT, where mobC encodes an auxiliary transfer protein with a dual function: autorepressor and stimulator of conjugative transfer. Here an interplay between MobC and NIC was demonstrated. MobC is required for efficient NIC cleavage of oriT in supercoiled DNA whereas NIC assists MobC in repression of the mobC-nic operon. A 7-bp arm of IR3 (IR3a) was identified as the binding site for NIC and the crucial nucleotides in IR3a for NIC recognition were defined. Fully active oriTRA3 was delineated to a 47-bp DNA segment encompassing a conserved cleavage site sequence, the NIC binding site IR3a and the MobC binding site OM . This highly efficient RA3 conjugative system with defined requirements for minimal oriT could find ample applications in biotechnology and computational biology where simple conjugative systems are needed. PMID:27101775

  15. Characterization and Evolution of the Cell Cycle-Associated Mob Domain-Containing Proteins in Eukaryotes

    PubMed Central

    Vitulo, Nicola; Vezzi, Alessandro; Galla, Giulio; Citterio, Sandra; Marino, Giada; Ruperti, Benedetto; Zermiani, Monica; Albertini, Emidio; Valle, Giorgio; Barcaccia, Gianni

    2007-01-01

    The MOB family includes a group of cell cycle-associated proteins highly conserved throughout eukaryotes, whose founding members are implicated in mitotic exit and co-ordination of cell cycle progression with cell polarity and morphogenesis. Here we report the characterization and evolution of the MOB domain-containing proteins as inferred from the 43 eukaryotic genomes so far sequenced. We show that genes for Mob-like proteins are present in at least 41 of these genomes, confirming the universal distribution of this protein family and suggesting its prominent biological function. The phylogenetic analysis reveals five distinct MOB domain classes, showing a progressive expansion of this family from unicellular to multicellular organisms, reaching the highest number in mammals. Plant Mob genes appear to have evolved from a single ancestor, most likely after the loss of one or more genes during the early stage of Viridiplantae evolutionary history. Three of the Mob classes are widespread among most of the analyzed organisms. The possible biological and molecular function of Mob proteins and their role in conserved signaling pathways related to cell proliferation, cell death and cell polarity are also presented and critically discussed. PMID:19468312

  16. Geochemistry and petrogenesis of the Gallego Volcanic Field, Solomon Islands, SW Pacific and geotectonic implications

    NASA Astrophysics Data System (ADS)

    Petterson, M. G.; Haldane, M. I.; Smith, D. J.; Billy, D.; Jordan, N. J.

    2011-08-01

    The Upper Miocene to present day Gallego Volcanic Field (GVF) is located in northwest Guadalcanal, Solomon Islands, SW Pacific, and potentially includes the offshore Savo volcano. The GVF is a multi-centred complex covering an area of ~ 800 km 2 on Guadalcanal and a further ~ 30 km 2 on the island of Savo, north of west Guadalcanal. GVF volcanism is characterised by effusive eruptions of lava, intrusion of sub-volcanic plutons, as well as pyroclastic flow and fall deposits dominated by block and ash flow deposits. Geochemical analysis of a representative suite of samples from the GVF demonstrates that the GVF comprise largely a 'main suite' of basalts to andesites and minor trachyandesites. The predominant mineralogy of the GVF comprises plagioclase, amphibole, clinopyroxene and magnetite-ilmenite. Associated with the 'main suite' are cognate nodules composed of hornblendite, gabbros, and clinopyroxenite. Interpretation of major and trace element geochemistry and petrographic studies suggests that fractionation was dominated by early clinopyroxene, and later amphibole + clinopyroxene + minor plagioclase. Geochemical features such as the incompatibility of Sr suggest that plagioclase largely crystallised en-masse late in the fractionation sequence. The presence of amphibole and late fractionation of plagioclase is suggestive of derivation from initially water-rich magmas. The region is characterised by strong geographically-related geochemical variations as evidenced by the Woodlark (and Manus) basins: basalts become more arc-like within the ocean basins with decreasing distance to the subducting trench. The GVF-Savo volcanoes are spatially and geochemically affected by deep N-S fractures that show some evidence of sympathetic geochemical variations with distance from the trench (e.g. Sr/Y ratios). Comparison with a range of international data for Th/Nb vs Pb/Nb and Dy/Yb vs SiO 2 indicate that: amphibole was indeed a strong controlling phase on magmatic evolution

  17. Mobbing, Stress, and Work Ability Index among Physicians in Bosnia and Herzegovina: Survey Study

    PubMed Central

    Pranjić, Nurka; Maleš-Bilić, Ljiljana; Beganlić, Azijada; Mustajbegović, Jadranka

    2006-01-01

    Aim To assess the frequency of reported mobbing and the association among mobbing, working environment factors, stress, health outcome, personality type, and work ability index in a sample of physicians in Bosnia and Herzegovina. Method We conducted a questionnaire survey using a validated self-reported questionnaire among 511 physicians in national health sector of Bosnia and Herzegovina. The questions covered five major categories of mobbing behavior. Characteristics of the work, perceived work environment and its effects, stress, health, and satisfaction with work and life were assessed by the standardized abridged form of Occupational Stress Questionnaire (OSQ). A standardized questionnaire Work Ability Index (WAI) was used to determine the relation between mobbing and work ability. Results Of 511 surveyed physicians, 387 (76%) physicians self-reported mobbing behavior in the working environment and 136 (26%) was exposed to persistent mobbing. More than a half of the physicians experienced threats to their professional status and almost a half felt isolated. Logistic regression analysis showed that lack of motivation, loss of self-esteem, loss of confidence, fatigue, and depressiveness were significantly associated with lack of support from colleagues. Intention to leave work was associated with lack of support from colleagues (OR 2.3, 95% CI, 1.065-3.535, t = 4.296, P = 0.003) and lack of support from superiors (OR 1.526, 95% CI, 0.976-2.076, t = 5.753; P = 0.001). Isolation or exclusion and threats to professional status were predictors for mental health symptoms. Persistent mobbing experience was a significant predictor for sick leave. Conclusion Exposure to persistent threat to professional status and isolation or exclusion as forms of mobbing are associated with mental health disturbances and lack of self-esteem and confidence. Setting up a system of support for physicians exposed to mobbing may have important benefits. PMID:17042067

  18. [Interpersonal relations as a source of risk of mobbing in the local police].

    PubMed

    Segurado Torres, Almudena; Agulló Tomás, Esteban; Rodríguez Suárez, Julio; Agulló Tomás, Ma Silveria; Boada i Grau, Joan; Medina Centeno, Raúl

    2008-11-01

    Social relations in the workplace are one of the main sources of risk for the onset of mobbing. In this work, we analyzed, through the perceived social climate, the influence of interpersonal relations on the characterization of the processes of mobbing, in a sample of local police (N = 235). In particular, the policemen and women's opinions of the quality of the personal relations among the group members and the treatment they receive from the command posts were assessed. The results of the study show that the development of guidelines of social interaction based on discrimination and abuse of authority are predicting variables of mobbing in this group. PMID:18940077

  19. Flocking and self-defense: experiments and simulations of avian mobbing

    NASA Astrophysics Data System (ADS)

    Kane, Suzanne Amador

    2011-03-01

    We have performed motion capture studies in the field of avian mobbing, in which flocks of prey birds harass predatory birds. Our empirical studies cover both field observations of mobbing occurring in mid-air, where both predator and prey are in flight, and an experimental system using actual prey birds and simulated predator ``perch and wait'' strategies. To model our results and establish the effectiveness of mobbing flight paths at minimizing risk of capture while optimizing predator harassment, we have performed computer simulations using the actual measured trajectories of mobbing prey birds combined with model predator trajectories. To accurately simulate predator motion, we also measured raptor acceleration and flight dynamics, well as prey-pursuit strategies. These experiments and theoretical studies were all performed with undergraduate research assistants in a liberal arts college setting. This work illustrates how biological physics provides undergraduate research projects well-suited to the abilities of physics majors with interdisciplinary science interests and diverse backgrounds.

  20. Neural Correlates of Threat Perception: Neural Equivalence of Conspecific and Heterospecific Mobbing Calls Is Learned

    PubMed Central

    Avey, Marc T.; Hoeschele, Marisa; Moscicki, Michele K.; Bloomfield, Laurie L.; Sturdy, Christopher B.

    2011-01-01

    Songbird auditory areas (i.e., CMM and NCM) are preferentially activated to playback of conspecific vocalizations relative to heterospecific and arbitrary noise [1]–[2]. Here, we asked if the neural response to auditory stimulation is not simply preferential for conspecific vocalizations but also for the information conveyed by the vocalization. Black-capped chickadees use their chick-a-dee mobbing call to recruit conspecifics and other avian species to mob perched predators [3]. Mobbing calls produced in response to smaller, higher-threat predators contain more “D” notes compared to those produced in response to larger, lower-threat predators and thus convey the degree of threat of predators [4]. We specifically asked whether the neural response varies with the degree of threat conveyed by the mobbing calls of chickadees and whether the neural response is the same for actual predator calls that correspond to the degree of threat of the chickadee mobbing calls. Our results demonstrate that, as degree of threat increases in conspecific chickadee mobbing calls, there is a corresponding increase in immediate early gene (IEG) expression in telencephalic auditory areas. We also demonstrate that as the degree of threat increases for the heterospecific predator, there is a corresponding increase in IEG expression in the auditory areas. Furthermore, there was no significant difference in the amount IEG expression between conspecific mobbing calls or heterospecific predator calls that were the same degree of threat. In a second experiment, using hand-reared chickadees without predator experience, we found more IEG expression in response to mobbing calls than corresponding predator calls, indicating that degree of threat is learned. Our results demonstrate that degree of threat corresponds to neural activity in the auditory areas and that threat can be conveyed by different species signals and that these signals must be learned. PMID:21909363

  1. Nuthatches eavesdrop on variations in heterospecific chickadee mobbing alarm calls

    PubMed Central

    Templeton, Christopher N.; Greene, Erick

    2007-01-01

    Many animals recognize the alarm calls produced by other species, but the amount of information they glean from these eavesdropped signals is unknown. We previously showed that black-capped chickadees (Poecile atricapillus) have a sophisticated alarm call system in which they encode complex information about the size and risk of potential predators in variations of a single type of mobbing alarm call. Here we show experimentally that red-breasted nuthatches (Sitta canadensis) respond appropriately to subtle variations of these heterospecific “chick-a-dee” alarm calls, thereby evidencing that they have gained important information about potential predators in their environment. This study demonstrates a previously unsuspected level of discrimination in intertaxon eavesdropping. PMID:17372225

  2. Clever strategists: Australian Magpies vary mobbing strategies, not intensity, relative to different species of predator.

    PubMed

    Koboroff, A; Kaplan, G; Rogers, Lj

    2013-01-01

    Anti-predator behaviour of magpies was investigated, using five species of model predators, at times of raising offspring. We predicted differences in mobbing strategies for each predator presented and also that raising juveniles would affect intensity of the mobbing event. Fourteen permanent resident family groups were tested using 5 different types of predator (avian and reptilian) known to be of varying degrees of risk to magpies and common in their habitat. In all, 210 trials were conducted (across three different stages of juvenile development). We found that the stage of juvenile development did not alter mobbing behaviour significantly, but predator type did. Aerial strategies (such as swooping) were elicited by taxidermic models of raptors, whereas a taxidermic model of a monitor lizard was approached on the ground and a model snake was rarely approached. Swooping patterns also changed according to which of the three raptors was presented. Our results show that, in contrast to findings in other species, magpies vary mobbing strategy depending on the predator rather than varying mobbing intensity. PMID:23638394

  3. Responses of squirrel monkeys to their experimentally modified mobbing calls

    NASA Astrophysics Data System (ADS)

    Fichtel, Claudia; Hammerschmidt, Kurt

    2003-05-01

    Previous acoustic analyses suggested emotion-correlated changes in the acoustic structure of squirrel monkey (Saimiri sciureus) vocalizations. Specifically, calls given in aversive contexts were characterized by an upward shift in frequencies, often accompanied by an increase in amplitude. In order to test whether changes in frequencies or amplitude are indeed relevant for conspecific listeners, playback experiments were conducted in which either frequencies or amplitude of mobbing calls were modified. Latency and first orienting response were measured in playback experiments with six adult squirrel monkeys. After broadcasting yaps with increased frequencies or amplitude, squirrel monkeys showed a longer orienting response towards the speaker than after the corresponding control stimuli. Furthermore, after broadcasting yaps with decreased frequencies or amplitude, squirrel monkeys showed a shorter orienting response towards the speaker than after the corresponding manipulated calls with higher frequencies or amplitude. These results suggest that changes in frequencies or amplitude were perceived by squirrel monkeys, indicating that the relationship between call structure and the underlying affective state of the caller agreed with the listener's assessment of the calls. However, a simultaneous increase in frequencies and amplitude did not lead to an enhanced response, compared to each single parameter. Thus, from the receiver's perspective, both call parameters may mutually replace each other.

  4. Measuring Mobility Limitations in Children with Cerebral Palsy: Interrater and Intrarater Reliability of a Mobility Questionnaire (MobQues)

    ERIC Educational Resources Information Center

    Van Ravesteyn, Nicolien T.; Dallmeijer, Annet J.; Scholtes, Vanessa A.; Roorda, Leo D.; Becher, Jules G.

    2010-01-01

    Aim: The objective of this study was to assess the reliability of a mobility questionnaire (MobQues) that was developed to measure the mobility limitations of children with cerebral palsy (CP) as rated by their parents. A clinical version of the questionnaire, consisting of 47 items (MobQues47), is available, as well as a research version with 28…

  5. Influence of Some Psychosocial Factors on Mobbing and Its Consequences among Employees Working with People with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Figueiredo-Ferraz, Hugo; Gil-Monte, Pedro R.; Grau-Alberola, Ester; Llorca-Pellicer, Marta; Garcia-Juesas, Juan A.

    2012-01-01

    Background: The problem of mobbing has attracted a great deal of attention over the past few years. This concern has increased the study of the phenomena, which has resulted in many scientific publications. Mobbing has been characterized as an emerging risk at work. The aim of this study was to analyse the influence of some psychosocial factors at…

  6. Flash Mob Science - Increasing Seismic Hazard Awareness and Preparedness in Oregon

    NASA Astrophysics Data System (ADS)

    Hoffman, J. S.; Lownsbery, D. S.

    2015-12-01

    Living in a region of imminent threat of a magnitude-9.0 (M­­­w ≈ ­9) earthquake is a daily reality for the millions of people predicted to be directly affected by a full rupture of the Cascadia Subduction Zone (CSZ), a fault line extending for hundreds of miles off the western coast of North America. Many coastal residents and visitors will also be affected by the tsunami caused by the rupture. How can the scientific community effectively communicate with those who are unaware of the threat and unprepared to respond? We are studying the effects of a novel approach to science outreach we have called Flash Mob Science. You have probably seen examples of flash mobs staging dynamic musical and dance routines to unsuspecting audiences. Similarly, Flash Mob Science takes the challenging (and often avoided) topic of earthquake and tsunami awareness and preparedness to unsuspecting audiences. However, Flash Mob Science seeks to move beyond having an audience of observers by engaging others as participants who enact important roles in an unfolding drama. We simulate the effects of seismic and tsunami events (e.g., prolonged surface shaking, falling debris, repeated tsunami surges) and model best practices in response (e.g., "Drop, Cover, Hold On" and moving quickly to high ground). True to the general flash mob model, when the Cascadia event inevitably does occur, it will come suddenly, and everyone affected will unavoidably be involved as actors in a real-life drama of immense scale. We seek to embed the learning of basic understandings and practices for an actual Cascadia event in a very small-scale, memorable, and sometimes even humorous, dramatization. We present here the lessons we have learned in the background, planning, and implementation of Flash Mob Science. We highlight the successes, limitations, and preliminary results evaluating the effectiveness of this outreach in developing learners' understandings and preparedness in an Oregon community affected by

  7. Determining the Effects of Mobbing on Organizational Commitment: A Case of Educational Sector in Pakistan

    ERIC Educational Resources Information Center

    ur Rehman, Fazal; Javed, Farwida; Khan, Aminullah; Nawaz, Tariq; Hyder, Shabir

    2015-01-01

    Mobbing is an activity where a group of people behave negatively against a person to enforce him/her in an unsecure position to push out of the organization. The study assessed this behavior by collecting data through questionnaires based survey from the employees of universities in Pakistan. Questionnaires were circulated among 400 employees of…

  8. Perception of mobbing during the study: results of a national quantitative research among Slovenian midwifery students.

    PubMed

    Došler, Anita Jug; Skubic, Metka; Mivšek, Ana Polona

    2014-09-01

    Mobbing, defined as sustained harassment among workers, in particular towards subordinates, merits investigation. This study aims to investigate Slovenian midwifery students' (2nd and 3rd year students of midwifery at the Faculty for Health Studies Ljubljana; the single educational institution for midwives in Slovenia) perception of mobbing, since management of acceptable behavioural interrelationships in midwifery profession forms already during the study, through professional socialization. Descriptive and causal-nonexperimental method with questionnaire was used. Basic descriptive statistics and measures for calculating statistical significance were carried out with SPSS 20.0 software version. All necessary ethical measures were taken into the consideration during the study to protect participants. The re- sults revealed that several participants experienced mobbing during the study (82.3%); 58.8% of them during their practical training and 23.5% from midwifery teachers. Students are often anxious and nervous in face of clinical settings (60.8%) or before faculty commitments (exams, presentations etc.) (41.2%). A lot of them (40.4%) estimate that mobbing affected their health. They did not show effective strategies to solve relationship problems. According to the findings, everyone involved in midwifery education, but above all students, should be provided with more knowledge and skills on successful management of conflict situations. PMID:25507371

  9. Mobbing and sitting tight at the nest as methods of avoiding brood parasitism.

    PubMed

    Rands, Sean A

    2012-04-01

    The arms race between brood parasites and their hosts has led to many different host behaviours for avoiding parasitism. Some of these behaviours are social, and require the presence of conspecifics to work effectively: in response to alarm calls, some species engage in mobbing behaviour where neighbours join nest tenants in attacking and repelling an invading brood parasite. There are risks involved for the neighbours, but it has been demonstrated that social mobbing allows individuals to learn about the presence of brood parasites in the environment, suggesting that social learning is occurring. Here, I consider whether using social signals to alert naive individuals to the presence of brood parasites is a suitable strategy, compared with sitting tight on the nest in response to the signal (which should reduce the chances of being parasitized). I also compare the efficiency of these strategies with the case where individuals fail to change behaviour in response a brood parasite. Using an individual-based simulation model, I demonstrate that both mobbing and sitting tight are effective strategies in response to a signal, and that mobbing is more effective when the chances of being parasitized increase. These results are discussed and compared with known host-brood parasite relationships. PMID:23565334

  10. Perception of mobbing during the study: results of a national quantitative research among Slovenian midwifery students.

    PubMed

    Došler, Anita Jug; Skubic, Metka; Mivšek, Ana Polona

    2014-09-01

    Mobbing, defined as sustained harassment among workers, in particular towards subordinates, merits investigation. This study aims to investigate Slovenian midwifery students' (2nd and 3rd year students of midwifery at the Faculty for Health Studies Ljubljana; the single educational institution for midwives in Slovenia) perception of mobbing, since management of acceptable behavioural interrelationships in midwifery profession forms already during the study, through professional socialization. Descriptive and causal-nonexperimental method with questionnaire was used. Basic descriptive statistics and measures for calculating statistical significance were carried out with SPSS 20.0 software version. All necessary ethical measures were taken into the consideration during the study to protect participants. The re- sults revealed that several participants experienced mobbing during the study (82.3%); 58.8% of them during their practical training and 23.5% from midwifery teachers. Students are often anxious and nervous in face of clinical settings (60.8%) or before faculty commitments (exams, presentations etc.) (41.2%). A lot of them (40.4%) estimate that mobbing affected their health. They did not show effective strategies to solve relationship problems. According to the findings, everyone involved in midwifery education, but above all students, should be provided with more knowledge and skills on successful management of conflict situations. PMID:25420387

  11. Medico-legal implications of mobbing. A false accusation of psychological harassment at the workplace.

    PubMed

    Jarreta, Begoña Martínez; García-Campayo, Javier; Gascón, Santiago; Bolea, Miguel

    2004-12-01

    Mobbing, or psychological harassment at the workplace, is usually defined as a situation in which a person or a group of people engage in extreme psychological violence against another person. In Spain, the number of reports for mobbing has increased extraordinarily in the last years. The reports are increasing dramatically not only before the Labour Courts, but also before the Civil Courts, with claims for damages, and before the Penal Court for offences causing physical or moral injury, etc., since at the present time this figure is not typified as an offence in the Spanish Penal Code. The high degree of complexity of this situation has given rise to frequent misuse of the term and to a number of false accusations of mobbing. A recent European Parliament Resolution on harassment at the workplace addressed the devastating consequences of false accusations. In this paper we present a case in which the "false" victim was mentally ill (paranoia) but succeed in generating an extreme dangerous environment of great harassment against the "false" assailants that were "falsely" accused of mobbing. Forensic diagnosis of the psychiatric disorder suffered by the "false" victim was essential to clarify the issue at the Penal Court. PMID:15639569

  12. [Work organization and mobbing: application of cognitive methodology in medical circle].

    PubMed

    Martire, M R; Lo Cascio, G; Picciotto, D; Lo Cascio, N

    2006-01-01

    Mobbing is a phenomenon produced for the most part by factors related to work organization. During the medical control of workers in Universitary Policlinico Hospital of Palermo, we used a methodology (in advance applied with effectiveness by ISPESL in other institutions) that is able to evidence factors of work organization causing Mobbing. 338 out 2060 workers (total staff) with different professional figures were recruited. We evidenced the working classes that had more troubles about communications of business information, about interpersonal relationships at work with top manager, with other members of team and with colleagues. Particularly doctors and OTA, in worrying percentage, stated that they suffered psychological molestations. Aim of our study was to assay a procedure that, even if it doesn't identify proclaimed mobbing phenomenon, enables us to acquire information about relationships between business management and workers and organizational aspects perceiving by subordinates. A I level study about a phenomenon in expansion is very useful to recognize preventively intentionally made mobbing actions. PMID:17380953

  13. Risk of psychiatric and neurological diseases in patients with workplace mobbing experience in Germany: a retrospective database analysis

    PubMed Central

    Kostev, Karel; Rex, Juliana; Waehlert, Lilia; Hog, Daniela; Heilmaier, Christina

    2014-01-01

    Introduction: The number of mobbing experiences recorded has increased during recent years and it has now been established as global phenomenon among the working population. The goal of our study was to analyze the incidence of certain neurologic and psychiatric diseases as a consequence of mobbing as compared with a control group and to examine the possible influence of previous diseases that occurred within one year before the first mobbing documentation on the incidence of mobbing. Material & methods: We used a large database (IMS® Disease Analyzer, Germany) to collect data from general practitioners in Germany from 01/2003 until 12/2012. Based on age, gender, and health insurance, patients with experience of mobbing were matched with a control group of patients who had not reported workplace mobbing and who were being treated by the same physicians. At first, diseases that occurred within one year before the bullying experience took place (“index date”) were noted and compared to a control group of similar composition in terms of gender, age, and health insurance. Subsequently, the prevalence of depression, anxiety, somatoform disorders, and sleep disorders following experiences of mobbing were determined. After adjustment to take into account the odds of bullying, the ratios of these diseases were assessed using a logistic regression model. Results: The study population consisted of n=2,625 patients and n=2,625 controls, of which 33% were men. The number of cases of bullying documented rose continuously from 2003 to 2011 and remained high in 2012. Those who would later become victims of mobbing demonstrated a considerably higher prevalence of diseases in general – these diseases were not confined to the neurologic-psychiatric spectrum. Following experiences of bullying, depression, anxiety, somatoform disorders, and sleep disorders were significantly more prevalent than in the control group (for all, p<0.05). Similarly, odds ratios (OR) representing the

  14. Mobbing in Bosnia and Herzegovina and the member states of the European Union

    NASA Astrophysics Data System (ADS)

    Rodic, V.

    2016-08-01

    Mobbing as a specific form of discrimination which applies only to the labor law, is a very young branch of labor law. It began to develop during the eighties of last century. This kind of psychoterror that appears in the workplace, was first spotted, formulated and diagnosed by the Swedish psychologist of German origin prof. Dr. Heinz Lejman (Heinz Leymann July 17, 1932.; Wolfenbuttel, Germany - 1999 Stockholm, Sweden). Today, the legal regulation of mobbing in terms of prevention, rules of behavior and sanctions is indispensable to every modern democratic state. I'll make a comparison of the legislative regulation provided by BiH with several European Union member states. I will compare the results of a survey conducted by the European Foundation for the Improvement of Living and Working Condition, during the year 2000. In the European Union Member States, with the results of the questionnaire for employees, which I conducted in Bosnia and Herzegovina. The conclusion I came to in this paper is: Bosnia and Herzegovina is lagging behind a lot of European Union member states, both in terms of prevention of mobbing, as well as legislation, that is insufficient to regulate this complex issue. Results of the questionnaire for the employees that I conducted in Bosnia and Herzegovina are devastating and alarming.

  15. Cases of mobbing activities as commonly seen in the healthcare sector in the world and in Turkey.

    PubMed

    Ofluoğlu, Gökhan; Somunoğlu, Sinem

    2012-01-01

    Service process on a site in the health sector does not only bring people and services into contact, but also all other people who share the fate of particular working medium. Although these people should cooperate and care about each other, contributing new merits to humanity with their synergy, meeting of people with the other people from time to time intertwine into a bitter, pain giving relation, like the way it happens with meeting of people with services. Owing to its controversy to humanitarian nature, religious and social values, the pain that human beings cause to one another is occasionally disguised behind a veil, thus turning into a life tragedy for individuals in the background. Mobbing which is commonly a confrontable problem in every workplace means psychological violence, enclosure, harassment, molestation or endurance. This study aims to draw attention to the precautions required to be taken against mobbing activities by analyzing situations of health employees who undergo mobbing actions in Turkey and in the World. To achieve this, the existing studies concerning mobbing in the healthcare sector have been examined. In conclusion; it is determined that mobbing activities towards healthcare workers have limited their communication possibilities, damaged social relations and social image, prevented vocational improvement and destroyed mental health of employees. With respect to mobbing behavior towards health employees, we should adopt a democratic, contributing, and guiding administration style, we should apply organizational justice, excessive work inspections must be reduced, work ethics and social responsibility awareness must be developed, we should clearly determine the duties and responsibilities, physical conditions must be improved and necessary legal arrangements concerning the subject must be made to be able to prevent mobbing. PMID:23216263

  16. MOBBED: a computational data infrastructure for handling large collections of event-rich time series datasets in MATLAB.

    PubMed

    Cockfield, Jeremy; Su, Kyungmin; Robbins, Kay A

    2013-01-01

    Experiments to monitor human brain activity during active behavior record a variety of modalities (e.g., EEG, eye tracking, motion capture, respiration monitoring) and capture a complex environmental context leading to large, event-rich time series datasets. The considerable variability of responses within and among subjects in more realistic behavioral scenarios requires experiments to assess many more subjects over longer periods of time. This explosion of data requires better computational infrastructure to more systematically explore and process these collections. MOBBED is a lightweight, easy-to-use, extensible toolkit that allows users to incorporate a computational database into their normal MATLAB workflow. Although capable of storing quite general types of annotated data, MOBBED is particularly oriented to multichannel time series such as EEG that have event streams overlaid with sensor data. MOBBED directly supports access to individual events, data frames, and time-stamped feature vectors, allowing users to ask questions such as what types of events or features co-occur under various experimental conditions. A database provides several advantages not available to users who process one dataset at a time from the local file system. In addition to archiving primary data in a central place to save space and avoid inconsistencies, such a database allows users to manage, search, and retrieve events across multiple datasets without reading the entire dataset. The database also provides infrastructure for handling more complex event patterns that include environmental and contextual conditions. The database can also be used as a cache for expensive intermediate results that are reused in such activities as cross-validation of machine learning algorithms. MOBBED is implemented over PostgreSQL, a widely used open source database, and is freely available under the GNU general public license at http://visual.cs.utsa.edu/mobbed. Source and issue reports for MOBBED

  17. Synthesis of vitamin D and erythemal irradiance obtained with a multiband filter radiometer and annual variation analysis in Río Gallegos, Argentina

    NASA Astrophysics Data System (ADS)

    Orte, P. F.; Wolfram, E. A.; Salvador, J.; D'Elia, R.; Paes Leme, N.; Quel, E. J.

    2011-01-01

    In this paper we examined the annual variability of the erythemal solar radiation (a health risk) and the solar irradiance for synthesis of vitamin D (a health benefit) in Río Gallegos, Argentina. We use ultraviolet radiation measurements made by a multiband filter radiometer GUV-541 and a Brewer spectrophotometer located at CEILAP-RG Station (CITEFA-CONICET) (51° 33' S, 69° 19' W). These measurements are weighted with action spectra published by the CIE (International Commission on Illumination). An action spectrum describes the relative effectiveness of different wavelengths in the generation of a particular biological response. The analyzed data correspond to September 2008-December 2009 period. The methodology used to obtain the erythemal irradiance and synthesis of vitamin D values combines irradiance measurements of a multiband filter radiometer with modeled values (output of radiative transfer model) and measurements of a Brewer spectrophotometer. This procedure increases the instrumental capabilities of this instrument. The synthesis of vitamin D and erythema are affected by UVB solar radiation. Therefore, its effect is strongly dependent of the stratospheric ozone amount, which undergoes large variations in the Río Gallegos city due to ozone hole passage and its influence on these sub-polar latitudes. We observed that could exist cases of sunburn for reasonable exposure in abnormal situations of low total ozone column, resulting in high levels of ultraviolet radiation. Furthermore, the synthesis of vitamin D through exposure to ultraviolet radiation would be lower than the appropriate values to the majority of the year for these latitudes. Therefore it is important to evaluate the annual variation of these quantities realizing seasonal balance between this health risk and this health benefit.

  18. The Xis2d protein of CTnDOT binds to the intergenic region between the mob and tra operons.

    PubMed

    Hopp, Crystal M; Gardner, Jeffrey F; Salyers, Abigail A

    2015-09-01

    CTnDOT is a 65kbp integrative and conjugative element (ICE) that carries genes encoding both tetracycline and erythromycin resistances. The excision operon of this element encodes Xis2c, Xis2d, and Exc proteins involved in the excision of CTnDOT from host chromosomes. These proteins are also required in the complex transcriptional regulation of the divergently transcribed transfer (tra) and mobilization (mob) operons of CTnDOT. Transcription of the tra operon is positively regulated by Xis2c and Xis2d, whereas, transcription of the mob operon is positively regulated by Xis2d and Exc. Xis2d is the only protein that is involved in the excision reaction, as well as the transcriptional regulation of both the mob and tra operons. This paper helps establish how Xis2d binds the DNA in the mob and tra region. Unlike other excisionase proteins, Xis2d binds a region of dyad symmetry. The binding site is located in the intergenic region between the mob and tra promoters, and once bound Xis2d induces a bend in the DNA. Xis2d binding to this region could be the preliminary step for the activation of both operons. Then the other proteins, like Exc, can interact with Xis2d and form higher order complexes. PMID:26212728

  19. What kind of diagnosis in a case of mobbing: post-traumatic stress disorder or adjustment disorder?

    PubMed

    Signorelli, Maria Salvina; Costanzo, Maria Cristina; Cinconze, Maria; Concerto, Carmen

    2013-01-01

    Over the last decade a consistent increase in stress-related psychological consequences at the workplace, usually called 'mobbing', has been seen. It claimed physical, psychical and social distress as its victims, leading to an increased incidence of many illnesses, such as psychosomatic disorders (ache, high blood pressure, chronic fatigue and insomnia) and psychiatric disturbances (high level of anxiety, depression and suicidal attempts). It was recently demonstrated that mobbing is significantly widespread among healthcare workers, especially among female nurses. In this report, we illustrate the case of a nurse who, after a brilliant career, underwent mobbing at the workplace, showing depression, anxiety and sleep disorders that required hospitalisation and a substantial intervention. PMID:23761569

  20. Ligand specificity of MobR, a transcriptional regulator for the 3-hydroxybenzoate hydroxylase gene of Comamonas testosteroni KH122-3s

    SciTech Connect

    Yoshida, Mariko; Hiromoto, Takeshi; Hosokawa, Keiichi; Yamaguchi, Hiroshi; Fujiwara, Shinsuke

    2007-10-19

    MobR from Comamonas testosteroni KH122-3s is a member of the MarR family of transcriptional regulators and functions as a repressor for the mobA gene that encodes a 3-hydroxybenzoate 4-hydroxylase. 3-Hydroxybenzoate binds to MobR as a ligand, resulting in an efficient induction of mobA. Various 3-hydroxybenzoate analogues were examined for their inducibilities using the mobA::lacZ transcriptional fusion system. {beta}-Galactosidase was induced by the addition of 2,3-dihydroxybenzoate or 3,5-dihydroxybenzoate besides 3-hydroxybenzoate, suggesting that the hydroxyl group at position 3 is critical in addition to the carboxyl group on the aromatic ring. A gel mobility-shift assay also showed that MobR was released from the target DNA in the presence of these compounds. Circular dichroism studies demonstrated that MobR adopted two conformational states corresponding to the 3-hydroxybenzoate-bound and unbound forms. Other ligands also induced the structural change as well; however, the tertiary structures of converted forms were different from those by 3-hydroxybenzoate.

  1. Growth Inhibition Accompanied by MOB1 Upregulation in Human Acute Lymphoid Leukemia Cells by 3-Deazaneplanocin A.

    PubMed

    Shen, Jianzhen; Su, Junnan; Wu, Dansen; Zhang, Feng; Fu, Haiying; Zhou, Huarong; Xu, Meihong

    2015-10-01

    Our purpose was to investigate the effect of 3-deazaneplanocin A (DZNep) on human T-cell acute lymphoid leukemia (T-ALL) cells, and to explore the underlying molecular mechanisms. The human T-ALL cell line Molt4 was treated with DZNep, and cell proliferation was examined. The expression of Mps one binder kinase activator 1 gene (MOB1) mRNA and protein was determined by RT-PCR and Western blotting, respectively. The histone modification effect of DZNep on the lysine 9 of histone 3 associated with MOB1 promoters was examined with chromatin immunoprecipitation and quantitative PCR, and CpG methylation in MOB1 promoters was detected by bisulfite sequencing PCR. DZNep treatment inhibited the growth of Molt4 cells. The expressions of MOB1 genes were upregulated by DZNep treatment, and histone methylations in their promoters were significantly reduced. The results indicate that DZNep is a promising therapeutic compound for the treatment of human T-ALL. PMID:26298709

  2. Distress Calls of a Fast-Flying Bat (Molossus molossus) Provoke Inspection Flights but Not Cooperative Mobbing.

    PubMed

    Carter, Gerald; Schoeppler, Diana; Manthey, Marie; Knörnschild, Mirjam; Denzinger, Annette

    2015-01-01

    Many birds and mammals produce distress calls when captured. Bats often approach speakers playing conspecific distress calls, which has led to the hypothesis that bat distress calls promote cooperative mobbing. An alternative explanation is that approaching bats are selfishly assessing predation risk. Previous playback studies on bat distress calls involved species with highly maneuverable flight, capable of making close passes and tight circles around speakers, which can look like mobbing. We broadcast distress calls recorded from the velvety free-tailed bat, Molossus molossus, a fast-flying aerial-hawker with relatively poor maneuverability. Based on their flight behavior, we predicted that, in response to distress call playbacks, M. molossus would make individual passing inspection flights but would not approach in groups or approach within a meter of the distress call source. By recording responses via ultrasonic recording and infrared video, we found that M. molossus, and to a lesser extent Saccopteryx bilineata, made more flight passes during distress call playbacks compared to noise. However, only the more maneuverable S. bilineata made close approaches to the speaker, and we found no evidence of mobbing in groups. Instead, our findings are consistent with the hypothesis that single bats approached distress calls simply to investigate the situation. These results suggest that approaches by bats to distress calls should not suffice as clear evidence for mobbing. PMID:26353118

  3. Distress Calls of a Fast-Flying Bat (Molossus molossus) Provoke Inspection Flights but Not Cooperative Mobbing

    PubMed Central

    Carter, Gerald; Schoeppler, Diana; Manthey, Marie; Knörnschild, Mirjam; Denzinger, Annette

    2015-01-01

    Many birds and mammals produce distress calls when captured. Bats often approach speakers playing conspecific distress calls, which has led to the hypothesis that bat distress calls promote cooperative mobbing. An alternative explanation is that approaching bats are selfishly assessing predation risk. Previous playback studies on bat distress calls involved species with highly maneuverable flight, capable of making close passes and tight circles around speakers, which can look like mobbing. We broadcast distress calls recorded from the velvety free-tailed bat, Molossus molossus, a fast-flying aerial-hawker with relatively poor maneuverability. Based on their flight behavior, we predicted that, in response to distress call playbacks, M. molossus would make individual passing inspection flights but would not approach in groups or approach within a meter of the distress call source. By recording responses via ultrasonic recording and infrared video, we found that M. molossus, and to a lesser extent Saccopteryx bilineata, made more flight passes during distress call playbacks compared to noise. However, only the more maneuverable S. bilineata made close approaches to the speaker, and we found no evidence of mobbing in groups. Instead, our findings are consistent with the hypothesis that single bats approached distress calls simply to investigate the situation. These results suggest that approaches by bats to distress calls should not suffice as clear evidence for mobbing. PMID:26353118

  4. Relationships between mobbing at work and MMPI-2 personality profile, posttraumatic stress symptoms, and suicidal ideation and behavior.

    PubMed

    Balducci, Cristian; Alfano, Vincenzo; Fraccaroli, Franco

    2009-01-01

    This study investigates the relationships between the experience of mobbing at work and personality traits and symptom patterns as assessed by means of the revised version of the Minnesota Multiphasic Personality Inventory (MMPI-2). Participants were 107 workers who had contacted mental health services because they perceived themselves as victims of mobbing. In line with previous research, the results showed that the MMPI-2 mean profile was characterized by a neurotic component as evidenced by elevations of Scales 1, 2, and 3 and a paranoid component as indicated by elevation of Scale 6. Contrary to previous research, a pattern of positive and significant correlations was found between the frequency of exposure to mobbing behaviors and the MMPI-2 clinical, supplementary, and content scales, including the posttraumatic stress scale. Only about half the participants showed a severity of posttraumatic stress symptoms indicative of a posttraumatic stress disorder. The frequency of exposure to mobbing predicted suicidal ideation and behavior, with depression only partially mediating this relationship. PMID:19297885

  5. Measuring Mobility Limitations in Children with Cerebral Palsy: Content and Construct Validity of a Mobility Questionnaire (MobQues)

    ERIC Educational Resources Information Center

    Van Ravesteyn, Nicolien T.; Scholtes, Vanessa A.; Becher, Jules G.; Roorda, Leo D.; Verschuren, Olaf; Dallmeijer, Annet J.

    2010-01-01

    Aim: The objective of this study was to assess the validity of a mobility questionnaire (MobQues) that was developed to measure parent-reported mobility limitations in children with cerebral palsy (CP). Method: The parents of 439 children with CP (256 males and 183 females; age range 2-18y; Gross Motor Function Classification System [GMFCS] levels…

  6. Boron analysis by electron microprobe using MoB4C layered synthetic crystals

    USGS Publications Warehouse

    McGee, J.J.; Slack, J.F.; Herrington, C.R.

    1991-01-01

    Preliminary electron microprobe studies of B distribution in minerals have been carried out using MoB4C-layered synthetic crystals to improve analytical sensitivity for B. Any microprobe measurements of the B contents of minerals using this crystal must include analyses for Cl to assess and correct for the interference of Cl X-rays on the BK?? peak. Microprobe analyses for B can be made routinely in tourmaline and other B-rich minerals, and minor B contents also can be determined in common rock-forming minerals. Incorporation of unusually high B contents in minerals other than borosilicates has been discovered in prograde and retrograde minerals in tourmalinites from the Broken Hill district, Australia, and may reflect high B activities produced during the metamorphism of tourmaline-rich rocks. -from Authors

  7. The Kinase Regulator Mob1 Acts as a Patterning Protein for Stentor Morphogenesis

    PubMed Central

    Slabodnick, Mark M.; Ruby, J. Graham; Dunn, Joshua G.; Feldman, Jessica L.; DeRisi, Joseph L.; Marshall, Wallace F.

    2014-01-01

    Morphogenesis and pattern formation are vital processes in any organism, whether unicellular or multicellular. But in contrast to the developmental biology of plants and animals, the principles of morphogenesis and pattern formation in single cells remain largely unknown. Although all cells develop patterns, they are most obvious in ciliates; hence, we have turned to a classical unicellular model system, the giant ciliate Stentor coeruleus. Here we show that the RNA interference (RNAi) machinery is conserved in Stentor. Using RNAi, we identify the kinase coactivator Mob1—with conserved functions in cell division and morphogenesis from plants to humans—as an asymmetrically localized patterning protein required for global patterning during development and regeneration in Stentor. Our studies reopen the door for Stentor as a model regeneration system. PMID:24823688

  8. Acid House and Thatcherism: noise, the mob, and the English countryside.

    PubMed

    Hill, Andrew

    2002-03-01

    This paper examines why the late 1980s youth subculture Acid House provoked a moral panic of the scale and intensity that it did. The subculture is conceived as presenting a disruptive presence to Thatcherism as an hegemonic project. The terms under which this occurred are examined through the themes of noise, the mob, and the disruption of bureaucratic authority. The presence of Acid House within the English countryside, and in particular the Home Counties, is situated as enhancing the problematic status of the subculture. The scale of measures taken against Acid House is related to Thatcherism's 'authoritarian populism'. Acid House is located in terms of a history of similar forms of popular cultural activity. The coverage of Acid House in The Sun and The Daily Mail, and the parliamentary debate around the second reading of the Entertainments (Increased Penalties) Act, are drawn upon throughout. PMID:11958680

  9. GlycoMob: an ion mobility-mass spectrometry collision cross section database for glycomics.

    PubMed

    Struwe, Weston B; Pagel, Kevin; Benesch, Justin L P; Harvey, David J; Campbell, Matthew P

    2016-06-01

    Ion mobility mass spectrometry (IM-MS) is a promising analytical technique for glycomics that separates glycan ions based on their collision cross section (CCS) and provides glycan precursor and fragment masses. It has been shown that isomeric oligosaccharide species can be separated by IM and identified on basis of their CCS and fragmentation. These results indicate that adding CCSs information for glycans and glycan fragments to searchable databases and analysis pipelines will increase identification confidence and accuracy. We have developed a freely accessible database, GlycoMob ( http://www.glycomob.org ), containing over 900 CCSs values of glycans, oligosaccharide standards and their fragments that will be continually updated. We have measured the absolute CCSs of calibration standards, biologically derived and synthetic N-glycans ionized with various adducts in positive and negative mode or as protonated (positive ion) and deprotonated (negative ion) ions. PMID:26314736

  10. Proteolysis of MOB1 by the ubiquitin ligase praja2 attenuates Hippo signalling and supports glioblastoma growth.

    PubMed

    Lignitto, Luca; Arcella, Antonietta; Sepe, Maria; Rinaldi, Laura; Delle Donne, Rossella; Gallo, Adriana; Stefan, Eduard; Bachmann, Verena A; Oliva, Maria A; Tiziana Storlazzi, Clelia; L'Abbate, Alberto; Brunetti, Arturo; Gargiulo, Sara; Gramanzini, Matteo; Insabato, Luigi; Garbi, Corrado; Gottesman, Max E; Feliciello, Antonio

    2013-01-01

    Human glioblastoma is the most frequent and aggressive form of brain tumour in the adult population. Proteolytic turnover of tumour suppressors by the ubiquitin-proteasome system is a mechanism that tumour cells can adopt to sustain their growth and invasiveness. However, the identity of ubiquitin-proteasome targets and regulators in glioblastoma are still unknown. Here we report that the RING ligase praja2 ubiquitylates and degrades Mob, a core component of NDR/LATS kinase and a positive regulator of the tumour-suppressor Hippo cascade. Degradation of Mob through the ubiquitin-proteasome system attenuates the Hippo cascade and sustains glioblastoma growth in vivo. Accordingly, accumulation of praja2 during the transition from low- to high-grade glioma is associated with significant downregulation of the Hippo pathway. These findings identify praja2 as a novel upstream regulator of the Hippo cascade, linking the ubiquitin proteasome system to deregulated glioblastoma growth. PMID:23652010

  11. Proteolysis of MOB1 by the ubiquitin ligase praja2 attenuates Hippo signalling and supports glioblastoma growth

    PubMed Central

    Lignitto, Luca; Arcella, Antonietta; Sepe, Maria; Rinaldi, Laura; Delle Donne, Rossella; Gallo, Adriana; Stefan, Eduard; Bachmann, Verena A.; Oliva, Maria A.; Tiziana Storlazzi, Clelia; L'Abbate, Alberto; Brunetti, Arturo; Gargiulo, Sara; Gramanzini, Matteo; Insabato, Luigi; Garbi, Corrado; Gottesman, Max E.; Feliciello, Antonio

    2013-01-01

    Human glioblastoma is the most frequent and aggressive form of brain tumour in the adult population. Proteolytic turnover of tumour suppressors by the ubiquitin–proteasome system is a mechanism that tumour cells can adopt to sustain their growth and invasiveness. However, the identity of ubiquitin–proteasome targets and regulators in glioblastoma are still unknown. Here we report that the RING ligase praja2 ubiquitylates and degrades Mob, a core component of NDR/LATS kinase and a positive regulator of the tumour-suppressor Hippo cascade. Degradation of Mob through the ubiquitin–proteasome system attenuates the Hippo cascade and sustains glioblastoma growth in vivo. Accordingly, accumulation of praja2 during the transition from low- to high-grade glioma is associated with significant downregulation of the Hippo pathway. These findings identify praja2 as a novel upstream regulator of the Hippo cascade, linking the ubiquitin proteasome system to deregulated glioblastoma growth. PMID:23652010

  12. What kind of diagnosis in a case of mobbing: post-traumatic stress disorder or adjustment disorder?

    PubMed Central

    Signorelli, Maria Salvina; Costanzo, Maria Cristina; Cinconze, Maria; Concerto, Carmen

    2013-01-01

    Over the last decade a consistent increase in stress-related psychological consequences at the workplace, usually called ‘mobbing’, has been seen. It claimed physical, psychical and social distress as its victims, leading to an increased incidence of many illnesses, such as psychosomatic disorders (ache, high blood pressure, chronic fatigue and insomnia) and psychiatric disturbances (high level of anxiety, depression and suicidal attempts). It was recently demonstrated that mobbing is significantly widespread among healthcare workers, especially among female nurses. In this report, we illustrate the case of a nurse who, after a brilliant career, underwent mobbing at the workplace, showing depression, anxiety and sleep disorders that required hospitalisation and a substantial intervention. PMID:23761569

  13. Giant honeybees (Apis dorsata) mob wasps away from the nest by directed visual patterns.

    PubMed

    Kastberger, Gerald; Weihmann, Frank; Zierler, Martina; Hötzl, Thomas

    2014-11-01

    The open nesting behaviour of giant honeybees (Apis dorsata) accounts for the evolution of a series of defence strategies to protect the colonies from predation. In particular, the concerted action of shimmering behaviour is known to effectively confuse and repel predators. In shimmering, bees on the nest surface flip their abdomens in a highly coordinated manner to generate Mexican wave-like patterns. The paper documents a further-going capacity of this kind of collective defence: the visual patterns of shimmering waves align regarding their directional characteristics with the projected flight manoeuvres of the wasps when preying in front of the bees' nest. The honeybees take here advantage of a threefold asymmetry intrinsic to the prey-predator interaction: (a) the visual patterns of shimmering turn faster than the wasps on their flight path, (b) they "follow" the wasps more persistently (up to 100 ms) than the wasps "follow" the shimmering patterns (up to 40 ms) and (c) the shimmering patterns align with the wasps' flight in all directions at the same strength, whereas the wasps have some preference for horizontal correspondence. The findings give evidence that shimmering honeybees utilize directional alignment to enforce their repelling power against preying wasps. This phenomenon can be identified as predator driving which is generally associated with mobbing behaviour (particularly known in selfish herds of vertebrate species), which is, until now, not reported in insects. PMID:25169944

  14. Giant honeybees (Apis dorsata) mob wasps away from the nest by directed visual patterns

    NASA Astrophysics Data System (ADS)

    Kastberger, Gerald; Weihmann, Frank; Zierler, Martina; Hötzl, Thomas

    2014-08-01

    The open nesting behaviour of giant honeybees (Apis dorsata) accounts for the evolution of a series of defence strategies to protect the colonies from predation. In particular, the concerted action of shimmering behaviour is known to effectively confuse and repel predators. In shimmering, bees on the nest surface flip their abdomens in a highly coordinated manner to generate Mexican wave-like patterns. The paper documents a further-going capacity of this kind of collective defence: the visual patterns of shimmering waves align regarding their directional characteristics with the projected flight manoeuvres of the wasps when preying in front of the bees' nest. The honeybees take here advantage of a threefold asymmetry intrinsic to the prey-predator interaction: (a) the visual patterns of shimmering turn faster than the wasps on their flight path, (b) they "follow" the wasps more persistently (up to 100 ms) than the wasps "follow" the shimmering patterns (up to 40 ms) and (c) the shimmering patterns align with the wasps' flight in all directions at the same strength, whereas the wasps have some preference for horizontal correspondence. The findings give evidence that shimmering honeybees utilize directional alignment to enforce their repelling power against preying wasps. This phenomenon can be identified as predator driving which is generally associated with mobbing behaviour (particularly known in selfish herds of vertebrate species), which is, until now, not reported in insects.

  15. Giant honeybees ( Apis dorsata) mob wasps away from the nest by directed visual patterns

    NASA Astrophysics Data System (ADS)

    Kastberger, Gerald; Weihmann, Frank; Zierler, Martina; Hötzl, Thomas

    2014-11-01

    The open nesting behaviour of giant honeybees ( Apis dorsata) accounts for the evolution of a series of defence strategies to protect the colonies from predation. In particular, the concerted action of shimmering behaviour is known to effectively confuse and repel predators. In shimmering, bees on the nest surface flip their abdomens in a highly coordinated manner to generate Mexican wave-like patterns. The paper documents a further-going capacity of this kind of collective defence: the visual patterns of shimmering waves align regarding their directional characteristics with the projected flight manoeuvres of the wasps when preying in front of the bees' nest. The honeybees take here advantage of a threefold asymmetry intrinsic to the prey-predator interaction: (a) the visual patterns of shimmering turn faster than the wasps on their flight path, (b) they "follow" the wasps more persistently (up to 100 ms) than the wasps "follow" the shimmering patterns (up to 40 ms) and (c) the shimmering patterns align with the wasps' flight in all directions at the same strength, whereas the wasps have some preference for horizontal correspondence. The findings give evidence that shimmering honeybees utilize directional alignment to enforce their repelling power against preying wasps. This phenomenon can be identified as predator driving which is generally associated with mobbing behaviour (particularly known in selfish herds of vertebrate species), which is, until now, not reported in insects.

  16. Dysregulated YAP1/TAZ and TGF-β signaling mediate hepatocarcinogenesis in Mob1a/1b-deficient mice

    PubMed Central

    Nishio, Miki; Sugimachi, Keishi; Goto, Hiroki; Wang, Jia; Morikawa, Takumi; Miyachi, Yosuke; Takano, Yusuke; Hikasa, Hiroki; Itoh, Tohru; Suzuki, Satoshi O.; Kurihara, Hiroki; Aishima, Shinichi; Leask, Andrew; Sasaki, Takehiko; Nakano, Toru; Nishina, Hiroshi; Nishikawa, Yuji; Sekido, Yoshitaka; Nakao, Kazuwa; Shin-ya, Kazuo; Mimori, Koshi; Suzuki, Akira

    2016-01-01

    Mps One Binder Kinase Activator (MOB)1A/1B are core components of the Hippo pathway that coactivate large tumor suppressor homolog (LATS) kinases. Mob1a/1b double deficiency in mouse liver (LMob1DKO) results in hyperplasia of oval cells and immature cholangiocytes accompanied by inflammatory cell infiltration and fibrosis. More than half of mutant mice die within 3 wk of birth. All survivors eventually develop liver cancers, particularly combined hepatocellular and cholangiocarcinomas (cHC-CCs) and intrahepatic cholangiocellular carcinomas (ICCs), and die by age 60 wk. Because this phenotype is the most severe among mutant mice lacking a Hippo signaling component, MOB1A/1B constitute the critical hub of Hippo signaling in mammalian liver. LMob1DKO liver cells show hyperproliferation, increased cell saturation density, hepatocyte dedifferentiation, enhanced epithelial–mesenchymal transition and cell migration, and elevated transforming growth factor beta(TGF-β)2/3 production. These changes are strongly dependent on Yes-Associated Protein-1 (Yap1) and partially dependent on PDZ-binding motif (Taz) and Tgfbr2, but independent of connective tissue growth factor (Ctgf). In human liver cancers, YAP1 activation is frequent in cHC-CCs and ICCs and correlates with SMAD family member 2 activation. Drug screening revealed that antiparasitic macrocyclic lactones inhibit YAP1 activation in vitro and in vivo. Targeting YAP1/TAZ with these drugs in combination with inhibition of the TGF-β pathway may be effective treatment for cHC-CCs and ICCs. PMID:26699479

  17. Dysregulated YAP1/TAZ and TGF-β signaling mediate hepatocarcinogenesis in Mob1a/1b-deficient mice.

    PubMed

    Nishio, Miki; Sugimachi, Keishi; Goto, Hiroki; Wang, Jia; Morikawa, Takumi; Miyachi, Yosuke; Takano, Yusuke; Hikasa, Hiroki; Itoh, Tohru; Suzuki, Satoshi O; Kurihara, Hiroki; Aishima, Shinichi; Leask, Andrew; Sasaki, Takehiko; Nakano, Toru; Nishina, Hiroshi; Nishikawa, Yuji; Sekido, Yoshitaka; Nakao, Kazuwa; Shin-Ya, Kazuo; Mimori, Koshi; Suzuki, Akira

    2016-01-01

    Mps One Binder Kinase Activator (MOB)1A/1B are core components of the Hippo pathway that coactivate large tumor suppressor homolog (LATS) kinases. Mob1a/1b double deficiency in mouse liver (LMob1DKO) results in hyperplasia of oval cells and immature cholangiocytes accompanied by inflammatory cell infiltration and fibrosis. More than half of mutant mice die within 3 wk of birth. All survivors eventually develop liver cancers, particularly combined hepatocellular and cholangiocarcinomas (cHC-CCs) and intrahepatic cholangiocellular carcinomas (ICCs), and die by age 60 wk. Because this phenotype is the most severe among mutant mice lacking a Hippo signaling component, MOB1A/1B constitute the critical hub of Hippo signaling in mammalian liver. LMob1DKO liver cells show hyperproliferation, increased cell saturation density, hepatocyte dedifferentiation, enhanced epithelial-mesenchymal transition and cell migration, and elevated transforming growth factor beta(TGF-β)2/3 production. These changes are strongly dependent on Yes-Associated Protein-1 (Yap1) and partially dependent on PDZ-binding motif (Taz) and Tgfbr2, but independent of connective tissue growth factor (Ctgf). In human liver cancers, YAP1 activation is frequent in cHC-CCs and ICCs and correlates with SMAD family member 2 activation. Drug screening revealed that antiparasitic macrocyclic lactones inhibit YAP1 activation in vitro and in vivo. Targeting YAP1/TAZ with these drugs in combination with inhibition of the TGF-β pathway may be effective treatment for cHC-CCs and ICCs. PMID:26699479

  18. [Mobbing, bullying and other forms of aggression among pupils as a source of stress in school. How far the "victims" are involved?].

    PubMed

    Seiffge-Krenke, Inge; Welter, Nicole

    2008-01-01

    Aggression among pupils is one of the frequent sources of stress in school. Aggression among pupils can display diverse forms and also has different origins. In this contribution, bullying, mobbing and relational aggression as different forms of aggression were described, based on recent research. In addition, a psychoanalytic treatment of a female adolescent is presented who suffered from mobbing. The treatment includes 70 hours work with the female patient and additional work with her parents. Based on this case study, it became obvious that it necessary to precisely analyse the own contribution for eliciting and maintaining aggression. PMID:18361185

  19. Workplace mobbing and bystanders' helping behaviour towards victims: the role of gender, perceived responsibility and anticipated stigma by association.

    PubMed

    Mulder, Roelie; Pouwelse, Mieneke; Lodewijkx, Hein; Bolman, Catherine

    2014-08-01

    We examined victims' perceived responsibility and bystanders' anticipated risk of being victimized themselves when others associate them with the victim (stigma by association, SBA) as possible antecedents of bystanders' helping behaviour towards a victim of workplace mobbing, and explored the effects of gender. Guided by the attribution model of social conduct (Weiner, 2006), a 2 × 2 vignette experiment was conducted. Participants were Dutch regional government employees (N = 161). Path analyses generally supported the hypotheses, but showed different results for women and men. In the strong (Vs. weak) responsibility condition, women reported less sympathy and more anger and men only more anger, which resulted in lower helping intention. Additionally, for men the results showed an unexpected direct positive effect of responsibility on helping intention. Furthermore, in the strong SBA condition, women and men reported more fear and men, unexpectedly, more anger. Consequently, helping intention decreased. The findings on gender are discussed in the context of social role theory, gender and emotion. Our findings suggest that to prevent and tackle mobbing, organizations and professionals should be aware of the attributional and emotional processes and gender differences in bystanders' helping behaviour. PMID:24990642

  20. [The relationship between mobbing and depression syndrome in the female working population of service industry: the problem statement and the prevention strategies in Sicilian environment].

    PubMed

    Romano, C; De Giovanni, L; Santoro, P E; Spataro, M

    2007-01-01

    The concept of "work" and the social interactions in the workplace contribute to develop the working satisfaction and the social and personal identity of the adult. The aim of the survey is that of checking up on the presence of a statistically significant relation between The Depression Syndrome and The Mobbing Phenomenon. It is necessary to understand and value if and how some of the employer's behaviours could have a heavy influence on the worker's psychophysical condition, up to causing a state of anxiety and depression. It has been used the now famous "LIPT" (Leymann Inventory of Psychological Terror), elaborated by Leymann at the beginning of the 90's. It is a short anonymous questionnaire recognized all over Europe as a standard to confirm the Mobbing existence in organizational contexts. The current version of the questionnaire is called "LIPT EGE", a more suitable tool to check the seven parameters of the Mobbing determination, as well as the quantification of the consequent harm. Some scales for depressive symptoms evaluation have been added to the Mobbing questionnaire: The Self Rating Depression Scale (SDS) and The Depression Status Inventory (DSI) of Zung. The questionnaires are administered to 500 workers women in public and private corporation in Sicily, exactly in Siracusa and Catania provinces. 206 women aged 34-50 have answered the questionnaires. In addition to the age and the sex, the distinction variables of the examined people are the position in the firm, nationality, vocational qualification, and the yearly gross income. The research has begun in july and has continued on august 2006. Attention has been focused only on the administrative sectors. Through the chi2 test and the exact Fisher test, the dependence between the changeable presence of depression in the two questionnaires (Zung 1 and Zung 2) and every single variable of the questionnaire on the Mobbing has been pointed out. In particular, the results establish a connection between

  1. A Degenerate Primer MOB Typing (DPMT) Method to Classify Gamma-Proteobacterial Plasmids in Clinical and Environmental Settings

    PubMed Central

    de la Cruz, Fernando

    2012-01-01

    Transmissible plasmids are responsible for the spread of genetic determinants, such as antibiotic resistance or virulence traits, causing a large ecological and epidemiological impact. Transmissible plasmids, either conjugative or mobilizable, have in common the presence of a relaxase gene. Relaxases were previously classified in six protein families according to their phylogeny. Degenerate primers hybridizing to coding sequences of conserved amino acid motifs were designed to amplify related relaxase genes from γ-Proteobacterial plasmids. Specificity and sensitivity of a selected set of 19 primer pairs were first tested using a collection of 33 reference relaxases, representing the diversity of γ-Proteobacterial plasmids. The validated set was then applied to the analysis of two plasmid collections obtained from clinical isolates. The relaxase screening method, which we call “Degenerate Primer MOB Typing” or DPMT, detected not only most known Inc/Rep groups, but also a plethora of plasmids not previously assigned to any Inc group or Rep-type. PMID:22792321

  2. The Structure of an NDR/LATS Kinase-Mob Complex Reveals a Novel Kinase-Coactivator System and Substrate Docking Mechanism.

    PubMed

    Gógl, Gergő; Schneider, Kyle D; Yeh, Brian J; Alam, Nashida; Nguyen Ba, Alex N; Moses, Alan M; Hetényi, Csaba; Reményi, Attila; Weiss, Eric L

    2015-05-01

    Eukaryotic cells commonly use protein kinases in signaling systems that relay information and control a wide range of processes. These enzymes have a fundamentally similar structure, but achieve functional diversity through variable regions that determine how the catalytic core is activated and recruited to phosphorylation targets. "Hippo" pathways are ancient protein kinase signaling systems that control cell proliferation and morphogenesis; the NDR/LATS family protein kinases, which associate with "Mob" coactivator proteins, are central but incompletely understood components of these pathways. Here we describe the crystal structure of budding yeast Cbk1-Mob2, to our knowledge the first of an NDR/LATS kinase-Mob complex. It shows a novel coactivator-organized activation region that may be unique to NDR/LATS kinases, in which a key regulatory motif apparently shifts from an inactive binding mode to an active one upon phosphorylation. We also provide a structural basis for a substrate docking mechanism previously unknown in AGC family kinases, and show that docking interaction provides robustness to Cbk1's regulation of its two known in vivo substrates. Co-evolution of docking motifs and phosphorylation consensus sites strongly indicates that a protein is an in vivo regulatory target of this hippo pathway, and predicts a new group of high-confidence Cbk1 substrates that function at sites of cytokinesis and cell growth. Moreover, docking peptides arise in unstructured regions of proteins that are probably already kinase substrates, suggesting a broad sequential model for adaptive acquisition of kinase docking in rapidly evolving intrinsically disordered polypeptides. PMID:25966461

  3. LOOPUS Mob-D: System concept for a public mobile satellite system providing integrated digital services for the Northern Hemisphere from an elliptical orbit

    NASA Technical Reports Server (NTRS)

    Kuhlen, H.; Horn, P.

    1990-01-01

    A new concept for a satellite based public mobile communications system, LOOPUS Mob-D, is introduced, whereby most of the classical problems in mobile satellite systems are approached in a different way. The LOOPUS system will offer a total capacity of 6000 high rate channels in three service areas (Europe, Asia, and North America), covering the entire Northern Hemisphere with a set of group special mobile (GSM) compatible mobile services, eventually providing the 'office in the car'. Special characteristics of the LOOPUS orbit and the communications network architecture are highlighted.

  4. The Structure of an NDR/LATS Kinase–Mob Complex Reveals a Novel Kinase–Coactivator System and Substrate Docking Mechanism

    PubMed Central

    Yeh, Brian J.; Alam, Nashida; Nguyen Ba, Alex N.; Moses, Alan M.; Hetényi, Csaba; Reményi, Attila; Weiss, Eric L.

    2015-01-01

    Eukaryotic cells commonly use protein kinases in signaling systems that relay information and control a wide range of processes. These enzymes have a fundamentally similar structure, but achieve functional diversity through variable regions that determine how the catalytic core is activated and recruited to phosphorylation targets. “Hippo” pathways are ancient protein kinase signaling systems that control cell proliferation and morphogenesis; the NDR/LATS family protein kinases, which associate with “Mob” coactivator proteins, are central but incompletely understood components of these pathways. Here we describe the crystal structure of budding yeast Cbk1–Mob2, to our knowledge the first of an NDR/LATS kinase–Mob complex. It shows a novel coactivator-organized activation region that may be unique to NDR/LATS kinases, in which a key regulatory motif apparently shifts from an inactive binding mode to an active one upon phosphorylation. We also provide a structural basis for a substrate docking mechanism previously unknown in AGC family kinases, and show that docking interaction provides robustness to Cbk1’s regulation of its two known in vivo substrates. Co-evolution of docking motifs and phosphorylation consensus sites strongly indicates that a protein is an in vivo regulatory target of this hippo pathway, and predicts a new group of high-confidence Cbk1 substrates that function at sites of cytokinesis and cell growth. Moreover, docking peptides arise in unstructured regions of proteins that are probably already kinase substrates, suggesting a broad sequential model for adaptive acquisition of kinase docking in rapidly evolving intrinsically disordered polypeptides. PMID:25966461

  5. ALS - resources

    MedlinePlus

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

  6. ALS Association

    MedlinePlus

    ... ALS. Find Out How Our Mission Leading the fight to treat and cure ALS through global research ... you participate, advocate, and donate, you advance the fight to find the cure and lead us toward ...

  7. Depth-related coupling relation between methane-oxidizing bacteria (MOBs) and sulfate-reducing bacteria (SRBs) in a marine sediment core from the Dongsha region, the South China Sea.

    PubMed

    Xu, Xiao-Ming; Fu, Shao-Ying; Zhu, Qing; Xiao, Xi; Yuan, Jian-Ping; Peng, Juan; Wu, Chou-Fei; Wang, Jiang-Hai

    2014-12-01

    The vertical distributions of methane-oxidizing bacteria (MOBs) and sulfate-reducing bacteria (SRBs) in the marine sediment core of DH-CL14 from the Dongsha region, the South China Sea, were investigated. To enumerate MOBs and SRBs, their specific genes of pmoA and apsA were quantified by a culture-independent molecular biological technique, real-time polymerase chain reaction (RT-PCR). The result shows that the pmoA gene copies per gram of sediments reached the maximum of 1,118,679 at the depth of 140-160 cm. Overall considering the detection precision, sample amount, measurement cost, and sensitivity to the seepage of methane from the oil/gas reservoirs or gas hydrates, we suggest that the depth of 140-160 cm may be the optimal sampling position for the marine microbial exploration of oils, gases, and gas hydrates in the Dongsha region. The data of the pmoA and apsA gene copies exhibit an evident coupling relation between MOBs and SRBs as illustrated in their vertical distributions in this sediment core, which may well be interpreted by a high sulfate concentration inhibiting methane production and further leading to the reduction of MOBs. In comparison with the numbers of the pmoA and apsA copies at the same sediment depth, we find out that there were two methane-oxidizing mechanisms of aerobic and anaerobic oxidation in this sediment core, i.e., the aerobic oxidation with free oxygen dominantly occurred above the depth of 210-230 cm, while the anaerobic oxidation with the other electron acceptors such as sulfates and manganese-iron oxides happened below the depth of 210-230 cm. PMID:25064353

  8. Processing of Mo-Si-B intermetallics by extrusion and oxidation properties of the extruded Tl-MoSi{sub 2}-MoB System

    SciTech Connect

    Summers, Eric

    1999-11-08

    An extrusion process was developed that is able to consistently produce large quantities of Mo-Si-B rods without the presence of defects. Binder removal from the extruded rods was studied in detail and it was determined that heating rates on the order of 0.02{degree}/minute (1.2{degree}/hour) are necessary to remove the binder without the formation of defects. This low heating rate resulted in debinding times in excess of 70 hours (approximately 3 days). Wicking was investigated as a means to decrease the time necessary for binder removal. Using 0.05{micro}m alumina powder as a wicking agent, binder removal times were reduced to 10 hours with heating rates up to 1{degree}/minute employed without defect formation. Once the extrusion process was complete the oxidation properties of the Tl-MoSi{sub 2}-MoB extruded phase assemblage was investigated. It was determined that this composition exhibits catastrophic oxidation or pesting in the temperature range of 660--760 C, resulting in the material turning to dust. Outside of this temperature range the composition is oxidatively stable. Continuous mass measurements were taken at 1,300, 1,450, and 1,600 C to determine the oxidation rate constants of this material. Parabolic rate constants of 6.9 x 10{sup {minus}3}, 1.3 x 10{sup {minus}3}, and 9.1 x 10{sup {minus}3} mg{sup 2}/cm{sup 4}/hr were determined for 1,300, 1,450, and 1,600 C respectively.

  9. Al Composites

    NASA Astrophysics Data System (ADS)

    Chandanayaka, Tharaka; Azarmi, Fardad

    2014-05-01

    In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% Ni3Al particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different Ni3Al powders with nominal particle size of -45 to +5 and +45 to 100 μm were used as reinforcement in this study. Cold sprayed Ni-Ni3Al samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles.

  10. AL Amyloidosis

    PubMed Central

    2012-01-01

    Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig) light chains (LC) (most commonly of lambda isotype) usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and/or immunofluorescence. Due to the

  11. [Mobbing, organizational dysfunction and bio-psycho-social effects: an integrated assessment. Preliminary data for the validation of the Questionnaire in the Neapoletan dialect on Distress at Work(Qn-DL)].

    PubMed

    Nolfe, Giovanni; Petrella, Claudio; Triassi, Maria; Zontini, Gemma; Uttieri, Simona; Pagliaro, Alessia; Blasi, Francesco; Cappuccio, Antonella; Nolfe, Giuseppe

    2013-01-01

    The aim of this study is to produce preliminary data about the validation of the "Naples-Questionnaire of Distress at Work" (nQ.DW). This inventory is a new assessment tool in order to evaluate the distress perceived in the working environment by means of the differentiation of the conditions linked to the mobbing from which related to organizational disfunction. The nQ-DW also measures the bio-psycho-social global effects of these two phenomena. The questionnaire has been administered to workers suffering of a psychopathological disturbance related to work distress and to a control group matched for the sociodemographic and working variables. The statistical analysis demonstrated a significant validity and reliability. The degree of internal coherence was satisfactory. The ROC curves allow the determination of a threshold value which allows to separate the workers subjected to mobbing and/or organizational stress from control-workers with an optimal reliability degree. The values of the area under the ROC curves show that the inventory has a high discriminating capacity. Future studies, based on a greater sample size, will be oriented to the analysis of the questionnaire by means of multivariate techniques like the factorial analysis. PMID:23914601

  12. [Organization of work, hardship at work, mobbing: new problem areas that must be considered by the competent doctor in formulating fitness evaluation].

    PubMed

    Lo Cascio, G; Martire, M R; Picciotto, D; Lo Cascio, N

    2007-01-01

    In recent years, in addition to the more common occupational-health risks (chemical, physical, biological), increasing importance is given to psychological and psychosomatic illness as a result of malfunction in the organization of work: burn-out, mobbing, maladjustment at work. In order to be able to evaluate the influence of such phenomenon whilst judging fitness in some working realities in Sicily, 18 small, medium and large dimension companies with a total of 1413 employees were examined. The typology of the work embraced the industrial, health, information-technology, construction and telephony sectors. The research involved analyzing, with the respective competent physicians, (in a few cases the same physician dealt with more than one company) the Risk Evaluation document, the clinical and risk records and the fitness evaluations. The analysis of the data obtained pointed out that of the 1413 employees observed, 87% was judged fit, 2% fit with limitation and/or prescription, almost 1% not fit. Notwithstanding the type of judgment, it was ascertained how in the above evaluation, only classical "physical" risks were evaluated (noise, MMC, VDT, etc.). The worker is judged as an individual removed from the general context of the company, of it's organization, or, as one who participates only by means of his various organs and apparatus, and who can singularly become ill because of exposure to some occupational risk. As a matter of fact, in none of the DVR's of the 18 companies object of the research, was an element of evaluation of the working organization found. Nor on the communication means, on the transparency of the procedures, on the quality of relations, lack of instruments or physical sites fit to working activity, nor to emotionally extreme working activities. It must therefore be emphasized that the competent physician only possesses the individual pathologies encountered in the various working situations. He lacks elements of evaluation that would

  13. Anomalous backscattered electron behavior of MoB and Mo{sub 5}SiB{sub 2} (T{sub 2}) phases in an as-cast Mo-B-Si alloy

    SciTech Connect

    Fournelle, J.H.; Nunes, C.A.; Perepezko, J.H.

    1996-12-31

    It is well established that backscattered electron (BSE) image contrast in SEM is primarily associated with differences in mean atomic number (Z) of the phases. The BSE coefficient increases with higher Z with slight dependence on beam energy E{sub 0}, except for some materials at <5 keV. We report here the anomalous BSE behavior of MoB and T{sub 2} (Mo{sub 5}SiB{sub 2}) phases observed imaging a 60Mo-30B-10Si (at%) alloy with a CAMECA SX-50. Specifies of the material and EMPA are reported in a companion communication. Mo-ss and Mo{sub 3}Si are also present. The drastic differences in BSE behavior are shown in Figures 1 (7 keV), 2 (15 keV), 2 (15 keV) and 3 (25 keV). The material has not been coated; addition of 100 {angstrom} carbon does not change the observed behavior.

  14. Synthesis and Characterization of an Alumina Forming Nanolaminated Boride: MoAlB

    NASA Astrophysics Data System (ADS)

    Kota, Sankalp; Zapata-Solvas, Eugenio; Ly, Alexander; Lu, Jun; Elkassabany, Omar; Huon, Amanda; Lee, William E.; Hultman, Lars; May, Steve J.; Barsoum, Michel W.

    2016-05-01

    The ‘MAlB’ phases are nanolaminated, ternary transition metal borides that consist of a transition metal boride sublattice interleaved by monolayers or bilayers of pure aluminum. However, their synthesis and properties remain largely unexplored. Herein, we synthesized dense, predominantly single-phase samples of one such compound, MoAlB, using a reactive hot pressing method. High-resolution scanning transmission electron microscopy confirmed the presence of two Al layers in between a Mo-B sublattice. Unique among the transition metal borides, MoAlB forms a dense, mostly amorphous, alumina scale when heated in air. Like other alumina formers, the oxidation kinetics follow a cubic time-dependence. At room temperature, its resistivity is low (0.36–0.49 μΩm) and – like a metal – drops linearly with decreasing temperatures. It is also a good thermal conductor (35 Wm‑1K‑1 at 26 °C). In the 25–1300 °C temperature range, its thermal expansion coefficient is 9.5 × 10‑6 K‑1. Preliminary results suggest the compound is stable to at least 1400 °C in inert atmospheres. Moderately low Vickers hardness values of 10.6 ± 0.3 GPa, compared to other transition metal borides, and ultimate compressive strengths up to 1940 ± 103 MPa were measured at room temperature. These results are encouraging and warrant further study of this compound for potential use at high temperatures.

  15. Synthesis and Characterization of an Alumina Forming Nanolaminated Boride: MoAlB.

    PubMed

    Kota, Sankalp; Zapata-Solvas, Eugenio; Ly, Alexander; Lu, Jun; Elkassabany, Omar; Huon, Amanda; Lee, William E; Hultman, Lars; May, Steve J; Barsoum, Michel W

    2016-01-01

    The 'MAlB' phases are nanolaminated, ternary transition metal borides that consist of a transition metal boride sublattice interleaved by monolayers or bilayers of pure aluminum. However, their synthesis and properties remain largely unexplored. Herein, we synthesized dense, predominantly single-phase samples of one such compound, MoAlB, using a reactive hot pressing method. High-resolution scanning transmission electron microscopy confirmed the presence of two Al layers in between a Mo-B sublattice. Unique among the transition metal borides, MoAlB forms a dense, mostly amorphous, alumina scale when heated in air. Like other alumina formers, the oxidation kinetics follow a cubic time-dependence. At room temperature, its resistivity is low (0.36-0.49 μΩm) and - like a metal - drops linearly with decreasing temperatures. It is also a good thermal conductor (35 Wm(-1)K(-1) at 26 °C). In the 25-1300 °C temperature range, its thermal expansion coefficient is 9.5 × 10(-6 )K(-1). Preliminary results suggest the compound is stable to at least 1400 °C in inert atmospheres. Moderately low Vickers hardness values of 10.6 ± 0.3 GPa, compared to other transition metal borides, and ultimate compressive strengths up to 1940 ± 103 MPa were measured at room temperature. These results are encouraging and warrant further study of this compound for potential use at high temperatures. PMID:27220751

  16. Synthesis and Characterization of an Alumina Forming Nanolaminated Boride: MoAlB

    PubMed Central

    Kota, Sankalp; Zapata-Solvas, Eugenio; Ly, Alexander; Lu, Jun; Elkassabany, Omar; Huon, Amanda; Lee, William E.; Hultman, Lars; May, Steve J.; Barsoum, Michel W.

    2016-01-01

    The ‘MAlB’ phases are nanolaminated, ternary transition metal borides that consist of a transition metal boride sublattice interleaved by monolayers or bilayers of pure aluminum. However, their synthesis and properties remain largely unexplored. Herein, we synthesized dense, predominantly single-phase samples of one such compound, MoAlB, using a reactive hot pressing method. High-resolution scanning transmission electron microscopy confirmed the presence of two Al layers in between a Mo-B sublattice. Unique among the transition metal borides, MoAlB forms a dense, mostly amorphous, alumina scale when heated in air. Like other alumina formers, the oxidation kinetics follow a cubic time-dependence. At room temperature, its resistivity is low (0.36–0.49 μΩm) and – like a metal – drops linearly with decreasing temperatures. It is also a good thermal conductor (35 Wm−1K−1 at 26 °C). In the 25–1300 °C temperature range, its thermal expansion coefficient is 9.5 × 10−6 K−1. Preliminary results suggest the compound is stable to at least 1400 °C in inert atmospheres. Moderately low Vickers hardness values of 10.6 ± 0.3 GPa, compared to other transition metal borides, and ultimate compressive strengths up to 1940 ± 103 MPa were measured at room temperature. These results are encouraging and warrant further study of this compound for potential use at high temperatures. PMID:27220751

  17. ALS - The cost cutter

    NASA Astrophysics Data System (ADS)

    Colucci, Frank

    1987-10-01

    The Advanced Launch System (ALS) development program will avail itself of existing technologies in the short term in order to produce an interim 'core' vehicle that may be operational by 1993; the full, booster-incorporating system objective will then be achieved in 1998. This programmatic 'decoupling' of booster and core vehicle development efforts will separate their funding peaks. The ALS program will cut costs by colocating manufacturing and launch facilities, using Al-Li alloys in booster primary structures, and aggressively applying 'paperless' CIM. The ALS launch vehicle configuration will be primarily determined by both payload requirements and flight frequency.

  18. Al-Anon/Alateen

    MedlinePlus

    Find an Al-Anon meeting Español | Français 2018 Int'l Convention Home About Group Meetings What If I'm not ready ... a meeting? What can I expect at an Al-Anon meeting? What was my first meeting like? ...

  19. [Environmental factors in ALS].

    PubMed

    Juntas-Morales, Raul; Pageot, Nicolas; Corcia, Philippe; Camu, William

    2014-05-01

    ALS is likely to be a disorder of multifactorial origin. Among all the factors that may increase the risk of ALS, environmental ones are being studied for many years, but in the recent years, several advances have pointed to a new interest in their potential involvement in the disease process, especially for the cyanotoxin BMAA. Food containing BMAA has been found on Guam, a well-known focus of ALS/parkinsonism/dementia and high levels of BMAA have been identified into the brain of these patients. The BMAA cyanotoxin is potentially ubiquitous and have also been found into the food of patients who died from ALS both in Europe and USA. BMAA can be wrongly integrated into the protein structure during mRNA traduction, competing with serine. This may induce abnormal protein folding and a subsequent cell death. Heavy metals, such as lead or mercury may be directly toxic for neuronal cells. Several works have suggested an increased risk of ALS in individuals chronically exposed to these metals. Exposure to pesticides has been suggested to be linked to an increased risk of developing ALS. The mechanism of their toxicity is likely to be mediated by paraoxonases. These proteins are in charge of detoxifying the organism from toxins, and particularly organophosphates. To date, there are insufficient scientific data to suggest that exposure to electromagnetic fields may increase the risk of having ALS. We are particularly missing longitudinal cohorts to demonstrate that risk. PMID:24703731

  20. All About ALS

    MedlinePlus

    ... External link, please review our exit disclaimer . Subscribe All About ALS Understanding a Devastating Disorder In the ... a coffee pot, or button a shirt. Eventually, all muscles under voluntary control are affected, and people ...

  1. Amyotrophic Lateral Sclerosis (ALS)

    MedlinePlus

    ... Pictures of ALS Mutant Proteins Support Two Major Theories About How the Disease is Caused May 2003 ... All NINDS-prepared information is in the public domain and may be freely copied. Credit to the ...

  2. Genetic Testing for ALS

    MedlinePlus

    ... Involved Donate Familial Amyotrophic Lateral Sclerosis (FALS) and Genetic Testing By Deborah Hartzfeld, MS, CGC, Certified Genetic ... guarantee a person will develop symptoms of ALS. Genetic Counseling If there is more than one person ...

  3. ALS synchrotron radiation shielding

    SciTech Connect

    Donahue, R.J.

    1995-10-01

    This note discusses the assumptions and results of synchrotron radiation shielding estimates for ALS bend magnet and wiggler beamlines. Estimates of gas bremsstrahlung production are not included and are dealt with elsewhere.

  4. What Is ALS?

    MedlinePlus

    ... scarring or hardening ("sclerosis") in the region. Motor neurons reach from the brain to the spinal cord ... the body. The progressive degeneration of the motor neurons in ALS eventually leads to their demise. When ...

  5. Rapidly solidified NiAl and FeAl

    NASA Technical Reports Server (NTRS)

    Gaydosh, D. J.; Crimp, M. A.

    1984-01-01

    Melt spinning was used to produce rapidly solidified ribbons of the B2 intermetallics NiAl and FeAl. Both Fe-40Al and Fe-45Al possessed some bend ductility in the as spun condition. The bend ductility of Fe-40Al, Fe-45Al, and equiatomic NiAl increased with subsequent heat treatment. Heat treatment at approximately 0.85 T (sub m) resulted in significant grain growth in equiatomic FeAl and in all the NiAl compositions. Low bend ductility in both FeAl and NiAl generally coincided with intergranular failure, while increased bend ductility was characterized by increasing amounts of transgranular cleavage fracture.

  6. Importance of sampling design and analysis in animal population studies: a comment on Sergio et al

    USGS Publications Warehouse

    Kery, M.; Royle, J. Andrew; Schmid, H.

    2008-01-01

    1. The use of predators as indicators and umbrellas in conservation has been criticized. In the Trentino region, Sergio et al. (2006; hereafter SEA) counted almost twice as many bird species in quadrats located in raptor territories than in controls. However, SEA detected astonishingly few species. We used contemporary Swiss Breeding Bird Survey data from an adjacent region and a novel statistical model that corrects for overlooked species to estimate the expected number of bird species per quadrat in that region. 2. There are two anomalies in SEA which render their results ambiguous. First, SEA detected on average only 6.8 species, whereas a value of 32 might be expected. Hence, they probably overlooked almost 80% of all species. Secondly, the precision of their mean species counts was greater in two-thirds of cases than in the unlikely case that all quadrats harboured exactly the same number of equally detectable species. This suggests that they detected consistently only a biased, unrepresentative subset of species. 3. Conceptually, expected species counts are the product of true species number and species detectability p. Plenty of factors may affect p, including date, hour, observer, previous knowledge of a site and mobbing behaviour of passerines in the presence of predators. Such differences in p between raptor and control quadrats could have easily created the observed effects. Without a method that corrects for such biases, or without quantitative evidence that species detectability was indeed similar between raptor and control quadrats, the meaning of SEA's counts is hard to evaluate. Therefore, the evidence presented by SEA in favour of raptors as indicator species for enhanced levels of biodiversity remains inconclusive. 4. Synthesis and application. Ecologists should pay greater attention to sampling design and analysis in animal population estimation. Species richness estimation means sampling a community. Samples should be representative for the

  7. Modulus measurements in ordered Co-Al, Fe-Al, and Ni-Al alloys

    NASA Technical Reports Server (NTRS)

    Harmouche, M. R.; Wolfenden, A.

    1985-01-01

    The composition and/or temperature dependence of the dynamic Young's modulus for the ordered B2 Co-Al, Fe-Al, and Ni-Al aluminides has been investigated using the piezoelectric ultrasonic composite oscillator technique (PUCOT). The modulus has been measured in the composition interval 48.49 to 52.58 at. pct Co, 50.87 to 60.2 at. pct Fe, and 49.22 to 55.95 at. pct Ni for Co-Al, Fe-Al, and Ni-Al, respectively. The measured values for Co-Al are in the temperature interval 300 to 1300 K, while those for the other systems are for ambient temperature only. The data points show that Co-Al is stiffer than Fe-Al, which is stiffer than Ni-Al. The data points for Fe-Al and Ni-Al are slightly higher than those reported in the literature.

  8. Al Shanker Remembers.

    ERIC Educational Resources Information Center

    American Educator, 2000

    2000-01-01

    In a 1996 interview shortly before his death, Al Shanker, longtime president of the American Federation of Teachers, discussed such topics as: his own educational experiences; how he learned about political fighting in the Boy Scouts; the appeal of socialism; multinational corporations and the nation state; teaching tough students; and John Dewey…

  9. ALS renewal moves forward

    NASA Astrophysics Data System (ADS)

    Falcone, R. W.; Feinberg, B.; Hussain, Z.; Kirz, J.; Krebs, G. F.; Padmore, H. A.; Robin, D. S.; Robinson, A. L.

    2007-11-01

    As the result of an extensive long-term planning process involving all its stakeholders—management, staff, and users—the ALS has seen its future and is aggressively moving ahead to implement its vision for keeping the facility at the cutting edge for the next 2-3 decades. The evolving strategic plan now in place aims to renew the ALS so it can address a new generation of fundamental questions about size dependent and dimensional-confinement phenomena at the nanoscale; correlation and complexity in physical, biological, and environmental systems; and temporal evolution, assembly, dynamics and ultrafast phenomena. The renewal spans three areas: (1) increased staffing at beamlines to support the growing user community and safety professionals to keep an increasingly complex facility hazard free; (2) implementing advances in accelerator, insertion device, beamline, and detector technology that will make it possible for ALS users to address emerging grand scientific and technological challenges with incisive world-class tools; and (3) construction of a user support building and guest housing that will increase the safety and user friendliness of the ALS by providing users office, meeting, experiment staging, and laboratory space for their work and on-site accommodations at reasonable rates.

  10. Fosetyl-al

    Integrated Risk Information System (IRIS)

    Fosetyl - al ; CASRN 39148 - 24 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  11. ALS Project Management Manual

    SciTech Connect

    Krupnick, Jim; Harkins, Joe

    2000-05-01

    This manual has been prepared to help establish a consistent baseline of management practices across all ALS projects. It describes the initial process of planning a project, with a specific focus on the production of a formal project plan. We feel that the primary weakness in ALS project management efforts to date stems from a failure to appreciate the importance of ''up-front'' project planning. In this document, we present a guide (with examples) to preparing the documents necessary to properly plan, monitor, and control a project's activities. While following the manual will certainly not guarantee good project management, failure to address the issues we raise will dramatically reduce the chance of success. Here we define success as meeting the technical goals on schedule and within the prescribed budget.

  12. ALS insertion devices

    SciTech Connect

    Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W.V.; Humphries, D.; Kincaid, B.; Lancaster, H.; Plate, D.

    1990-11-01

    The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system. 18 refs., 9 figs., 5 tabs.

  13. Ausbildung als zentrale Aufgabe

    NASA Astrophysics Data System (ADS)

    Krämer, Walter; Schmerbach, Sibylle

    Anders als Lesen und Schreiben zählen Grundkenntnisse in Statistik heute noch nicht zu den Voraussetzungen einer sinnvollen Teilhabe am Sozialgeschehen. Und auch in der akademischen Statistik-Ausbildung gibt es noch einiges zu tun. Das vorliegende Kapitel zeichnet die Geschichte dieser akademischen Ausbildung an deutschen Universitäten nach dem zweiten Weltkrieg nach, stellt aktuelle Defizite vor und weist auf mögliche Verbesserungen hin.

  14. [Individual and environmental antecedents of mobbing].

    PubMed

    Mościcka, Agnieszka; Drabek, Marcin

    2010-01-01

    The aim of the article is to present the most common risk factors of bullying at the workplace. In the relevant literature one can find two main classes of bullying risk factors: environmental and individual. The most important environmental predictors of bullying are negative social climate, ineffective social communication and poor work organization. Among individual risk factors of bullying the most frequently pointed are functional features, such as low level of assertiveness, lack of social skills, ineffective coping with difficult situations and the few relatively stable individual characteristics, like neuroticism, trait anxiety, hostility and aggression. Most authors underline the crucial role of environmental factors in the development of bullying, and the individual characteristics of persons involved in this pathological relation are usually seen as the modifiers of bullying process. PMID:20865859

  15. When Active Citizenship Becomes "Mob Rule."

    ERIC Educational Resources Information Center

    Thompson, Jane

    2000-01-01

    Recent protests and vigilante actions in Britain related to pedophiles raise issues for adult educators. Educators must be prepared to struggle along with learners in the creation of knowledge based on reason and emotion and shaped by ethical and political considerations. (SK)

  16. Child-abusers face mob justice.

    PubMed

    Sebunya, C

    1996-06-01

    In Uganda, before the acquired immunodeficiency syndrome (AIDS) epidemic, rape or sexual abuse of children was not considered a serious offense by the public, although the maximum criminal offense for rape was death. Because so many young girls are testing positive for human immunodeficiency virus (HIV), and due to the efforts of women's groups, public opinion is changing. According to the United Nations International Children's Fund (UNICEF), girls aged 9-15 years are five times more likely to be infected with HIV than boys of the same age. Adults, who fear their peers may be infected with HIV, turn to children; some AIDS patients believe sleeping with a virgin girl will cure their illness. Uganda is targeting a $15 million project to protect children 5-15 years of age. A study commissioned by the Uganda National Council for Women and Children in 1994 found that in Kabale district 31% of girls and 15% of boys had been abused, many by teachers. In Masaka district, the Council found that 30% of women had been coerced into sex; bosses abuse their maids, and customers abuse alcohol sellers. According to police, rape is the second most common crime in Uganda. Victims are reluctant to come forward to testify; rape victims can be shunned in their communities and may be considered ineligible for marriage. Cases which make it to court rarely get a fair hearing, according to the Council of Women, because the men handling the cases often favor the culprits. FIDA, an association of women lawyers, Action for Development (ACFODE), and the National Association of Women's Organisations in Uganda (NAWOU) are lobbying for tougher laws on rape and closed courts. They are pressuring newspapers to not disclose the names of victims. Although many expect the Ministry of Women to take the lead in this area, it has been unable to do so, because of a lack of funds; it received two-thirds of its budget for 1994-95, an indication, perhaps, of the Ugandan government's intentions. Two figures are shown; one concerns the relation of abuser to child, while the other concerns the action taken on abuse cases. PMID:12291112

  17. Optical gain characteristics in Al-rich AlGaN/AlN quantum wells

    SciTech Connect

    Oto, Takao; Banal, Ryan G.; Funato, Mitsuru; Kawakami, Yoichi

    2014-05-05

    The optical gain characteristics of Al-rich AlGaN/AlN quantum wells (QWs) were assessed by the variable stripe length method at room temperature. An Al{sub 0.79}Ga{sub 0.21}N/AlN QW with a well width of 5 nm had a large optical gain of 140 cm{sup −1}. Increasing the excitation length induced a redshift due to the gain consumption and the consequent saturation of the amplified spontaneous emission. Moreover, a change in the dominant gain polarization with Al composition, which was attributed to switching of the valence band ordering of strained AlGaN/AlN QWs at Al compositions of ∼0.8, was experimentally demonstrated.

  18. AL Amyloidosis and Agent Orange

    MedlinePlus

    ... for survivors' benefits . Research on AL amyloidosis and herbicides The Health and Medicine Division (formally known as ... to the compounds of interest found in the herbicide Agent Orange and AL amyloidosis." VA made a ...

  19. Al(+)-ligand binding energies

    NASA Technical Reports Server (NTRS)

    Sodupe, M.; Bauschlicher, Charles W., Jr.

    1991-01-01

    Ab initio calculations are used to optimize the structure and determine the binding energies of Al(+) to a series of ligands. For Al(+)-CN, the bonding was found to have a large covalent component. For the remaining ligands, the bonding is shown to be electrostatic in origin. The results obtained for Al(+) are compared with those previously reported for Mg(+).

  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. Studies of 27Al NMR in EuAl4

    NASA Astrophysics Data System (ADS)

    Niki, H.; Nakamura, S.; Higa, N.; Kuroshima, H.; Toji, T.; Yogi, M.; Nakamura, A.; Hedo, M.; Nakama, T.; Ōnuki, Y.; Harima, H.

    2015-03-01

    EuAl4 orders antiferromagnetically at TN ≈ 16 K with an effective magnetic moment of 8.02 μB. In the paramagnetic phase, the magnetic susceptibility of EuAl4 follows the Curie-Weiss law with a positive Curie-Weiss temperature θP = +14 K. The antiferromagnetic state is changed into the field induced ferromagnetic state at a critical field Hc of approximately 2 T. In order to microscopically investigate the magnetic and electronic properties in EuAl4, the NMR measurements of EuAl4 have been carried out at temperatures between 2 and 300 K, applying an external magnetic field of approximately 6.5 T. The 27Al NMR spectra corresponding to Al(I) and Al(II) sites are obtained. From the 27Al NMR spectra, the isotropic part Kiso and anisotropic part Kaniso of Knight shift, and nuclear quadrupole frequncy νQ are obtained. The Kiso and Kaniso shift to negative side with decreasing temperature due to the RKKY interaction. These temperature dependences follow the Curie-Weiss law with θP = +14 K, which is consistent with that of the magnetic susceptibility. From the K - χ plot, the values of the hyperfine fields Hhf_iso and Hhf_aniso are -3.231 and -0.162 kOe/μB for Al(I) site, and -1.823 and -0.264 kOe/μB for Al(II) site, respectively. The values of νQ of 27Al nucleus for Al(I) and Al(II) sites are approximately 0.865 and 0.409 MHz, respectively. The nuclear relaxation time T1 of 27Al NMR for both sites is almost constant in the paramagnetic phase, while the value of 1/T1 is abruptly decreased in the ordered ferromagnetic state.

  2. Interfacial characterization of Al-Al thermocompression bonds

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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 SiO2 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 SiO2. However, the dicing yield was 33% for Al on Si and 98% for Al on SiO2, 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 SiO2 are discussed.

  3. Studies of 27Al NMR in SrAl4

    NASA Astrophysics Data System (ADS)

    Niki, Haruo; Higa, Nonoka; Kuroshima, Hiroko; Toji, Tatsuki; Morishima, Mach; Minei, Motofumi; Yogi, Mamoru; Nakamura, Ai; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika; Harima, Hisatomo

    A charge density wave (CDW) transition at TCDW = 243 K and a structural phase (SP) transition at approximately 100 K occur in SrAl4 with the BaAl4-type body center tetragonal structure, which is the divalent and non-4f electron reference compound of EuAl4. To understand the behaviors of the CDW and SP transitions, the 27Al NMR measurements using a single crystal and a powder sample of SrAl4 have been carried out. The line width below TCDW is modulated by an electrical quadruple interaction between 27Al nucleus and CDW charge modulation. The incommensurate CDW state below TCDW changes into a different structure below TSP. The temperature dependences of Knight shifts of 27Al(I) and 27Al(II) show the different behaviors. The temperature variation of 27Al(I) Knight shift shows anomalies at the CDW and SP transition temperatures, revealing the shift to negative side below TCDW, which is attributable to the core polarization of the d-electrons. However, 27Al(II) Knight shift keeps almost constant except for the small shift due to the SP transition. The 1/T1T of 27Al(I) indicates the obvious changes due to the CDW and SP transitions, while that of 27Al(II) takes a constant value. The density of state at the Fermi level at Al(I) site below 60 K would be about 0.9 times less than that above TCDW.

  4. ALS Performance Summary - Update

    SciTech Connect

    Waters, A M; Brown, W D; Martz, Jr., H E

    2004-09-30

    High Energy Density Physics (HEDP) experiments play an important role in corroborating the improved physics codes that underlie LLNL's Stockpile Stewardship mission. Conducting these experiments, whether on the National Ignition Facility (NIF) or another national facility such as Omega, will require not only improvement in the diagnostics for measuring the experiment, but also detailed knowledge of the as-built target components and assemblies themselves. To assist in this effort, a defined set of well-known reference standards designed to represent a range of HEDP targets have been built and are being used to quantify the performance of different characterization techniques [Hibbard, et al. 2004]. Without the critical step of using reference standards for qualifying characterization tools there can be no verification of either commercial or internally-developed characterization techniques and thus an uncertainty in the input to the physics code models would exist.

  5. Doppelthydrophile Blockcopolymere als Mineralisationstemplate

    NASA Astrophysics Data System (ADS)

    Kasparova, Pavla

    2002-07-01

    Die vorliegende Arbeit beschäftigt sich mit der Synthese und den Eigenschaften von doppelthydrophilen Blockcopolymeren und ihrer Anwendung in einem biomimetischen Mineralisationsprozeß von Calciumcarbonat und Bariumsulfat. Doppelthydrophile Blockcopolymere bestehen aus einem hydrophilen Block, der nicht mit Mineralien wechselwirkt und einem zweiten Polyelektrolyt-Block, der stark mit Mineraloberflächen wechselwirkt. Diese Blockcopolymere wurden durch ringöffnende Polymerisation von N-carboxyanhydriden (NCA's) und a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 als Initiator hergestellt. Die hergestellten Blockcopolymere wurden als effektive Wachstumsmodifikatoren für die Kristallisation von Calciumcarbonat und Bariumsulfat Mineralien eingesetzt. Die so erhaltenen Mineralpartikel (Kugeln, Hantel, eiförmige Partikel) wurden durch Lichtmikroskopie in Lösung, SEM und TEM charakterisiert. Röntgenweitwinkelstreuung (WAXS) wurde verwendet, um die Modifikation von Calciumcarbonat zu ermitteln und die Größe der Calciumcarbonat- und Bariumsulfat-Nanopartikel zu ermitteln. This work describes the synthesis and characterization of double hydrophilic block copolymers and their use in a biomimetic mineralization process of Calcium Carbonate and Barium Sulfate. Double hydrophilic block copolymers consist of a hydrophilic block that does not interact with minerals and another hydrophilic polyelectrolyte block that strongly interacts with mineral surfaces. These polymers were synthesised via ring opening polymerisation of N-carboxyanhydride (NCA), and the first hydrophilic block a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 was used as an initiator. The prepared block copolymers were used as effective crystal growth modifiers to control the crystallization of Calcium Carbonate and Barium Sulfate minerals. The resulting mineral particles (spheres, dumbbells, egg-like particles) were characterised by light microscopy in solution, by SEM, and by TEM. X-Ray scattering

  6. 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.

  7. Rub' al Khali, Arabia

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Rub' al Khali is 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. The desert covers 650,000 square kilometers, more than the area of France. Largely unexplored until recently, the desert is 1000 km long and 500 km wide. The first documented journeys made by Westerners were those of Bertram Thomas in 1931 and St. John Philby in 1932. With daytime temperatures reaching 55 degrees Celsius, and dunes taller than 330 meters, the desert may be one of the most forbidding places on Earth.

    The image was acquired December 2, 2005, covers an area of 54.8 x 61.9 km, and is located near 20.7 degrees north latitude, 53.6 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.

  8. 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.

  9. Undulators at the ALS

    SciTech Connect

    Hoyer, E.; Akre, J.; Chin, J.

    1994-07-01

    At Lawrence Berkeley Laboratory`s (LBL) Advanced Light Source (ALS), three 4.6 m long undulators have been completed, tested and installed. A fourth is under construction. The completed undulators include two 5.0 cm period length, 89 period devices (U5.0s) which achieve a 0.85 T effective field at a 14 mm minimum gap and a 8.0 cm period length, 55 period device (U8.0) that reaches a 1.2 T effective field at a 14 mm minimum gap. The undulator under construction is a 10.0 cm period length, 43 period device (U10.0) that is designed to achieve 0.98 T at a 23 mm gap. Undulator magnetic gap variation (rms) is within 25 microns over the periodic structure length. Reproducibility of the adjustable magnetic gap has been measured to be within +/{minus} 5 microns. Gap adjusting range is from 14 mm to 210 mm, which can be scanned in one minute. The 5.1 m long vacuum chambers are flat in the vertical direction to within 0.74 mm and straight in the horizontal direction to within 0.08 mm over the 4.6 m magnetic structure sections. Vacuum chamber base pressures after UHV beam conditioning are. in the mid 10{sup {minus}11} Torr range and storage ring operating pressures with full current are in the low 10{sup {minus}10} Torr range. Measurements show that the uncorrelated magnetic field errors are 0.23%, and 0.20% for the two U5.Os and the U8.0 respectively and that the field integrals are small over the 1 cm by 6 cm beam aperture. Device description, fabrication, and measurements are presented.

  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.

    2016-07-01

    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. Modeling neuronal vulnerability in ALS.

    PubMed

    Roselli, Francesco; Caroni, Pico

    2014-08-20

    Using computational models of motor neuron ion fluxes, firing properties, and energy requirements, Le Masson et al. (2014) reveal how local imbalances in energy homeostasis may self-amplify and contribute to neurodegeneration in ALS. PMID:25144872

  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. Characteristics of CeCoIn5/Al/AlOx/Nb and CeCoIn5/Al/AlOx/Al Tunnel Junctions

    SciTech Connect

    Petrovic, C.; Nevirkovets, I.P.; Chernyashevskyy, O.; Hu, R.; Ketterson, J.B.; Sarma, B.K.

    2009-03-03

    We report characteristics of CeCoIn{sub 5}/Al/AlO{sub x}/Nb and CeCoIn{sub 5}/Al/AlO{sub x}/Al tunnel junctions fabricated on the (0 0 1) surface of CeCoIn{sub 5} crystal platelets. The main result of this work is the observation of a low Josephson current (as compared with that expected from the Ambegaokar-Baratoff formula), which is consistent with idea that the order parameter in the heavy-fermion superconductor CeCoIn{sub 5} has unconventional pairing symmetry.

  14. Influence of boron vacancies on phase stability, bonding and structure of MB 2 (M  =  Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W) with AlB2 type structure

    NASA Astrophysics Data System (ADS)

    Dahlqvist, Martin; Jansson, Ulf; Rosen, Johanna

    2015-11-01

    Transition metal diborides in hexagonal AlB2 type structure typically form stable MB 2 phases for group IV elements (M  =  Ti, Zr, Hf). For group V (M  =  V, Nb, Ta) and group VI (M  =  Cr, Mo, W) the stability is reduced and an alternative hexagonal rhombohedral MB 2 structure becomes more stable. In this work we investigate the effect of vacancies on the B-site in hexagonal MB 2 and its influence on the phase stability and the structure for TiB2, ZrB2, HfB2, VB2, NbB2, TaB2, CrB2, MoB2, and WB2 using first-principles calculations. Selected phases are also analyzed with respect to electronic and bonding properties. We identify trends showing that MB 2 with M from group V and IV are stabilized when introducing B-vacancies, consistent with a decrease in the number of states at the Fermi level and by strengthening of the B-M interaction. The stabilization upon vacancy formation also increases when going from M in period 4 to period 6. For TiB2, ZrB2, and HfB2, introduction of B-vacancies have a destabilizing effect due to occupation of B-B antibonding orbitals close to the Fermi level and an increase in states at the Fermi level.

  15. Influence of boron vacancies on phase stability, bonding and structure of MB₂ (M  =  Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W) with AlB₂ type structure.

    PubMed

    Dahlqvist, Martin; Jansson, Ulf; Rosen, Johanna

    2015-11-01

    Transition metal diborides in hexagonal AlB2 type structure typically form stable MB2 phases for group IV elements (M  =  Ti, Zr, Hf). For group V (M  =  V, Nb, Ta) and group VI (M  =  Cr, Mo, W) the stability is reduced and an alternative hexagonal rhombohedral MB2 structure becomes more stable. In this work we investigate the effect of vacancies on the B-site in hexagonal MB2 and its influence on the phase stability and the structure for TiB2, ZrB2, HfB2, VB2, NbB2, TaB2, CrB2, MoB2, and WB2 using first-principles calculations. Selected phases are also analyzed with respect to electronic and bonding properties. We identify trends showing that MB2 with M from group V and IV are stabilized when introducing B-vacancies, consistent with a decrease in the number of states at the Fermi level and by strengthening of the B-M interaction. The stabilization upon vacancy formation also increases when going from M in period 4 to period 6. For TiB2, ZrB2, and HfB2, introduction of B-vacancies have a destabilizing effect due to occupation of B-B antibonding orbitals close to the Fermi level and an increase in states at the Fermi level. PMID:26445165

  16. Stimulated emission in AlGaN/AlGaN quantum wells with different Al content

    NASA Astrophysics Data System (ADS)

    Mickevičius, J.; Jurkevičius, J.; Kazlauskas, K.; Žukauskas, A.; Tamulaitis, G.; Shur, M. S.; Shatalov, M.; Yang, J.; Gaska, R.

    2012-02-01

    Stimulated emission (SE) is studied in AlGaN/AlGaN multiple quantum wells (MQWs) with different Al content grown on sapphire substrate. The spectra of spontaneous and stimulated emission and their transformations with increasing temperature as well as stimulated emission thresholds were measured in the temperature range from 8 to 300 K. Phonon-assisted band broadening in low-Al-content MQWs and double-scaled potential profile in high-Al-content MQWs were observed in the samples and linked with carrier localization conditions. The temperature dependence of the stimulated emission threshold was similar in the samples where the stimulated transitions occur between extended states and in the samples where the transitions occur in localized states. The stimulated emission threshold depends predominantly on the density of nonradiative recombination centers.

  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. In memory of Al Cameron

    NASA Astrophysics Data System (ADS)

    Cowan, John; Truran, James W.

    Al Cameron, who died recently (October 3, 2005) at 80, was one of the giants in astrophysics. His insights were profound and his interests were wide-ranging. Originally trained as a nuclear physicist, he made major contributions in a number of fields, including nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, and the origin of the Solar System and the Moon. In 1957, Cameron and, independently, Burbidge, Burbidge, Fowler and Hoyle, wrote seminal papers on nuclear astrophysics. Most of our current ideas concerning ele- ment formation in stars have followed from those two pioneering and historical works. Al also made many contributions in the field of Solar System physics. Particularly noteworthy in this regard was Cameron's work on the formation of the Moon. Al was also a good friend and mentor of young people. Al Cameron will be missed by many in the community both for his scientific contributions and for his friendship.

  19. 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.

  20. 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.

  1. Corrosion Behavior of Al-Al3Ni and Al-Al2Cu Functionally Graded Materials Fabricated by a Centrifugal Method

    NASA Astrophysics Data System (ADS)

    Noda, Kazuhiko; Miyahara, Keita; Watanabe, Yoshimi

    2008-02-01

    Intermetallic compounds, such as Al3Ni and Al2Cu, are effective for enhancing the mechanical properties of an alloy. Al-Al3Ni and Al-Al2Cu functionally graded materials (FGMs) might be attractive materials for advanced materials. Al-Al3Ni and Al-Al2Cu FGMs were fabricated by a centrifugal method; the centrifugal method is an extremely effective method for fabricating FGMs. Al-Al3Ni and Al-Al2Cu FGMs that had a graded distribution of intermetallic compounds could be produced by this in-situ centrifugal method. Particle size, particle shape and the distribution of intermetallic compounds were controlled by varying the content of the alloy element (Ni, Cu) in the master alloy, the cooling rate in casting and the gravity number. The casting mechanism is explained in terms of the microstructures of the Al-Al3Ni and Al-Al2Cu FGMs fabricated by this method. The corrosion behavior of the FGMs was investigated by electrochemical analysis. Polarization curves of the FGMs in a borate solution were measured by a potentiodynamic method. The presence of Al2Cu exerted a larger effect on the corrosion behavior of the FGMs than Al3Ni. Analysis of the polarization curve parameters was effective for evaluating the corrosion resistance of the FGMs.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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.

  3. High Density Sliding at Ta/Al and Al/Al Interfaces

    SciTech Connect

    Hammerberg, J. E.; Germann, T. C.; Ravelo, R.

    2006-07-28

    We present 3D-nonequilibrium molecular dynamics results for the velocity dependence of the frictional force at smooth sliding interfaces for Ta and Al single crystals. For Ta/Al we consider Al(100)/Ta(100) and Al(111)/Ta(110) interfaces sliding along [001] and [11(bar sign)0]fcc /[001]bcc respectively. These are compared with Al(111)/Al(100) interfaces at the same loads, corresponding to a pressure of 15 GPa. Both interfacial pairs show similar behavior in the velocity dependence of the frictional force: a low velocity regime with an increasing frictional force followed by a strain induced transformation regime at velocities above approximately 1/10 the transverse sound speed, followed by a fluidized interface at high velocities. For both interfacial pairs, the high velocity dependence of the frictional force exhibits power law behavior, Ft {proportional_to} v-{beta} with {beta}=3/4. We discuss the structural changes that influence dissipation in each of these regimes.

  4. Superconductivity in Al/Al2O3 interface

    NASA Astrophysics Data System (ADS)

    Palnichenko, A. V.; Vyaselev, O. M.; Mazilkin, A. A.; Khasanov, S. S.

    2016-06-01

    Metastable superconductivity at Tc ≈ 65 K has been observed in Al foil subjected to special oxidation process, according to the ac magnetic susceptibility and electrical resistance measurements. Comparison of the ac susceptibility and the dc magnetization measurements infers that the superconductivity arises within the interfacial granular layer formed during the oxidation process between metallic aluminum and its oxide.

  5. AlN/Fe/AlN nanostructures for magnetooptic magnetometry

    SciTech Connect

    Lišková-Jakubisová, E. Višňovský, Š.; Široký, P.; Hrabovský, D.; Pištora, J.

    2014-05-07

    AlN/Fe/AlN/Cu nanostructures with ultrathin Fe grown by sputtering on Si substrates are evaluated as probes for magnetooptical (MO) mapping of weak currents. They are considered for a laser wavelength of λ = 410 nm (3.02 eV) and operate at oblique light incidence angles, φ{sup (0)}, to enable detection of both in-plane and out-of-plane magnetization. Their performance is evaluated in terms of MO reflected wave electric field amplitudes. The maximal MO amplitudes in AlN/Fe/AlN/Cu are achieved by a proper choice of layer thicknesses. The nanostructures were characterized by MO polar Kerr effect at φ{sup (0)} ≈ 5° and longitudinal Kerr effect spectra (φ{sup (0)} = 45°) at photon energies between 1 and 5 eV. The nominal profiles were refined using a model-based analysis of the spectra. Closed form analytical expressions are provided, which are useful in the search for maximal MO amplitudes.

  6. ALS - A unique design approach

    NASA Astrophysics Data System (ADS)

    Chamberlain, Roger A.

    1990-09-01

    An advanced launch system (ALS), which is intended to be flexible and to deliver a wide range of payloads at a reduced cost, is discussed. The ALS concept also features total quality management, modular subsystems, standardized interfaces, standardized missions, and off-line payload encapsulation. The technological improvements include manufacturing of dry structures, use of composite materials, adaptive guidance and control systems, and laser-initiated radar systems. The operational improvements range from paperless management, to rocket engine leak detection devices and automated ground operations.

  7. 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.

  8. Large rectification magnetoresistance in nonmagnetic Al/Ge/Al heterojunctions

    NASA Astrophysics Data System (ADS)

    Zhang, Kun; Li, Huan-Huan; Grünberg, Peter; Li, Qiang; Ye, Sheng-Tao; Tian, Yu-Feng; Yan, Shi-Shen; Lin, Zhao-Jun; Kang, Shi-Shou; Chen, Yan-Xue; Liu, Guo-Lei; Mei, Liang-Mo

    2015-09-01

    Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can generate a significant direct-current voltage, and this rectification voltage strongly varies with the external magnetic field. We find that the rectification magnetoresistance in Al/Ge Schottky heterojunctions is as large as 250% at room temperature, which is greatly enhanced as compared with the conventional magnetoresistance of 70%. The findings of rectification magnetoresistance open the way to the new nonmagnetic Ge-based spintronics devices of large rectification magnetoresistance at ambient temperature under the alternating-current due to the simultaneous implementation of the rectification and magnetoresistance in the same devices.

  9. AlSb/InAs/AlSb quantum wells

    NASA Technical Reports Server (NTRS)

    Kroemer, Herbert

    1990-01-01

    Researchers studied the InAs/AlSb system recently, obtaining 12nm wide quantum wells with room temperature mobilities up to 28,000 cm(exp 2)/V center dot S and low-temperature mobilities up to 325,000 cm(exp 2)/V center dot S, both at high electron sheet concentrations in the 10(exp 12)/cm(exp 2) range (corresponding to volume concentrations in the 10(exp 18)/cm(exp 2) range). These wells were not intentionally doped; the combination of high carrier concentrations and high mobilities suggest that the electrons are due to not-intentional modulation doping by an unknown donor in the AlSb barriers, presumably a stoichiometric defect, like an antisite donor. Inasmuch as not intentionally doped bulk AlSb is semi-insulating, the donor must be a deep one, being ionized only by draining into the even deeper InAs quantum well. The excellent transport properties are confirmed by other observations, like excellent quantum Hall effect data, and the successful use of the quantum wells as superconductive weak links between Nb electrodes, with unprecendentedly high critical current densities. The system is promising for future field effect transistors (FETs), but many processing problems must first be solved. Although the researchers have achieved FETs, the results so far have not been competitive with GaAs FETs.

  10. 76 FR 66986 - Shawn M. Gallegos, D.D.S., Decision and Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... King Pharmacy, 54 FR. 34,623, 34,627 (DEA 1989). ``A sanction may not be imposed* * *except on.... 844(a). \\26\\ See Kuen H. Chen, M.D., 58 FR. 65,401, 65,402 (DEA 1993). A. The Public Interest Standard.... See David H. Gillis, M.D., 58 FR. 37,507, 37,508 (DEA 1993); see also D & S Sales, 71 FR. 37,607,...

  11. The effect of Si in Al-alloy on electromigration performance in Al filled vias

    NASA Astrophysics Data System (ADS)

    Kageyama, Makiko; Hashimoto, Keiichi; Onoda, Hiroshi

    1998-01-01

    Electromigration performance of vias filled with Al-Si-Cu alloys on Ti glue layers was investigated in comparison with W-stud vias. In Al-Si-Cu filled vias, voids were formed at only a few locations in the test structure, while voids were formed at every via in W-stud via chains. It is supposed that Al moves through the Al-Si-Cu via during electromigration in spite of the existence of a glue layer at the via bottom. This phenomenon was observed only in the vias filled with Al-Si-Cu alloy. Al movement was prohibited in Al-Cu filled vias. In Al-Si-Cu filled vias, an Al-Ti-Si alloy was formed at the via bottom while Al3Ti was formed at Al-Cu filled vias. Al is speculated to move through this Al-Ti-Si alloy during electromigration.

  12. Emerging mechanisms of molecular pathology in ALS

    PubMed Central

    Peters, Owen M.; Ghasemi, Mehdi; Brown, Robert H.

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a devastating degenerative disease characterized by progressive loss of motor neurons in the motor cortex, brainstem, and spinal cord. Although defined as a motor disorder, ALS can arise concurrently with frontotemporal lobal dementia (FTLD). ALS begins focally but disseminates to cause paralysis and death. About 10% of ALS cases are caused by gene mutations, and more than 40 ALS-associated genes have been identified. While important questions about the biology of this disease remain unanswered, investigations of ALS genes have delineated pathogenic roles for (a) perturbations in protein stability and degradation, (b) altered homeostasis of critical RNA- and DNA-binding proteins, (c) impaired cytoskeleton function, and (d) non-neuronal cells as modifiers of the ALS phenotype. The rapidity of progress in ALS genetics and the subsequent acquisition of insights into the molecular biology of these genes provide grounds for optimism that meaningful therapies for ALS are attainable. PMID:25932674

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

    DOE PAGESBeta

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

    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. Furthermore, the formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamicallymore » driven process.« less

  14. Synthesis of AlN/Al Polycrystals along with Al Nanoparticles Using Thermal Plasma Route

    SciTech Connect

    Kanhe, Nilesh S.; Nawale, A. B.; Kulkarni, N. V.; Bhoraskar, S. V.; Mathe, V. L.; Das, A. K.

    2011-07-15

    This paper for the first time reports the (200) oriented growth of hexagonal Aluminum nitride crystals during synthesis of aluminum nanoparticles in dc transferred arc thermal plasma reactor by gas phase condensation in nitrogen plasma. The structural and morphological study of as synthesized AlN crystal and aluminium nanoparticles was done by using the x-ray diffraction method, scanning electron microscopy and transmission electron microscopy.

  15. Synthesis of Al-Al2O3 and Al-Aln Nanoparticle Composites Via Electric Explosion of Wires

    NASA Astrophysics Data System (ADS)

    Lerner, M. I.; Lozhkomoev, A. S.; Pervikov, A. V.; Bakina, O. V.

    2016-07-01

    Composite Al-Al2O3 and Al-AlN nanoparticles were synthesized via electric explosion of aluminum wires in an argon-oxygen gas mixture and in nitrogen. The parameters of electric explosion and gas medium affect the size and relative content of nitride and aluminum oxide in the nanoparticles. Processes of forming chemical compounds during aluminum oxidation at the contact surface between explosive products and gas and of nitrogen diffusions into the nanoparticles of the condensed phase are considered.

  16. Investigation of Wear Anisotropy in a Severely Deformed Al-Al3Ti Composite

    NASA Astrophysics Data System (ADS)

    El-Hadad, Shimaa; Sato, Hisashi; Watanabe, Yoshimi

    2012-09-01

    In the current investigation, Al-Al3Ti composite was processed by equal channel angular pressing (ECAP). ECAP was carried out using routes A and BC up to eight passes of deformation. It was observed that increasing the number of ECAP passes causes fragmentation of Al3Ti platelet particles and decreases their sizes compared to their original sizes in the undeformed Al-Al3Ti specimens. Moreover, the microstructure of route A-ECAPed Al-Al3Ti composite samples showed a strong alignment of the fragmented Al3Ti particles parallel to the pressing axis. On the other hand, ECAPed Al-Al3Ti alloy specimens by route BC have a relatively homogeneous distribution of Al3Ti particles. Because of the platelet Al3Ti particle fragmentation by ECAP, all the ECAPed specimens showed small anisotropy in their wear property in spite of this observed anisotropic microstructure induced by route A-ECAP.

  17. Investigation of Wear Anisotropy in a Severely Deformed Al-Al3Ti Composite

    NASA Astrophysics Data System (ADS)

    El-Hadad, Shimaa; Sato, Hisashi; Watanabe, Yoshimi

    2012-05-01

    In the current investigation, Al-Al3Ti composite was processed by equal channel angular pressing (ECAP). ECAP was carried out using routes A and BC up to eight passes of deformation. It was observed that increasing the number of ECAP passes causes fragmentation of Al3Ti platelet particles and decreases their sizes compared to their original sizes in the undeformed Al-Al3Ti specimens. Moreover, the microstructure of route A-ECAPed Al-Al3Ti composite samples showed a strong alignment of the fragmented Al3Ti particles parallel to the pressing axis. On the other hand, ECAPed Al-Al3Ti alloy specimens by route BC have a relatively homogeneous distribution of Al3Ti particles. Because of the platelet Al3Ti particle fragmentation by ECAP, all the ECAPed specimens showed small anisotropy in their wear property in spite of this observed anisotropic microstructure induced by route A-ECAP.

  18. 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.

  19. 77 FR 73732 - In the Matter of Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-11

    ... Matter of Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al-Jihad, aka The... al-Rafidayn, aka The Organization of al-Jihad's Base of Operations in Iraq, aka al-Qaida of Jihad in Iraq, aka al-Qaida in Iraq, aka al-Qaida in Mesopotamia, aka al-Qaida in the Land of the Two...

  20. The Al-Al3Ni Eutectic Reaction: Crystallography and Mechanism of Formation

    NASA Astrophysics Data System (ADS)

    Fan, Yangyang; Makhlouf, Makhlouf M.

    2015-09-01

    The characteristics of the Al-Al3Ni eutectic structure are examined with emphasis on its morphology and crystallography. Based on these examinations, the mechanism of formation of this technologically important eutectic is postulated. It is found that a thin shell of α-Al forms coherently around each Al3Ni fiber. The excellent thermal stability of the Al-Al3Ni eutectic may be attributed to the presence of this coherent layer.

  1. Reply to Pachai et al.

    PubMed

    Harrison, William J; Bex, Peter J

    2016-05-01

    Peripheral vision is fundamentally limited by the spacing between objects. When asked to report a target's identity, observers make erroneous reports that sometimes match the identity of a nearby distractor and sometimes match a combination of target and distractor features. The classification of these errors has previously been used to support competing 'substitution' [1] or 'averaging' [2] models of the phenomenon known as 'visual crowding'. We recently proposed a single model in which both classes of error occur because observers make their reports by sampling from a biologically-plausible population of weighted responses within a region of space around the target [3]. It is critical to note that there is no probabilistic substitution or averaging process in our model; instead, we argue that neither substitution nor averaging occur, but that these are misclassifications of the distribution of reports that emerge when a population response distribution is sampled. This is a fundamentally different way of thinking about crowding, and on this basis we claim to have provided a mechanism unifying categorically distinct perceptual errors. Our goal was not to model all crowding phenomena, such as the release from crowding when target and flanks differ in color or depth [4]. Pachai et al.[5] have suggested that our model is not unifying because it inaccurately predicts perceptual performance for a particular stimulus. Although we agree that our model does not predict their data, this specific demonstration overlooks the critical aspect of the model: perceptual reports are drawn from a weighted population code. We show that Pachai et al.'s [5] own data actually provide evidence for the population code we have described [3], and we suggest a biologically-plausible analysis of their stimuli that provides a computational basis for their 'grouping' account of crowding. PMID:27166690

  2. Effects of the Al content on pore structures of porous TieAl alloys

    SciTech Connect

    Jaing, Y; He, Y H; Xu, N P; Zou, J; Huang, B; Lui, C T

    2008-01-01

    Porous TieAl alloys with different nominal compositions were fabricated through a reactive synthesis of Ti and Al elemental powders. It has been found that the pore parameters vary with the Al contents, indicating that the nature of the pores can be manipulated through changing the Al contents. In addition, detailed structural characterizations showed that the fabricated porous TieAl alloys can have three crystalline phases (i.e., a2-Ti3Al, g-TiAl, and TiAl3) when using different compositions. The fundamental reasons behind these phenomena have been explored.

  3. Everyday Life with ALS: A Practical Guide

    MedlinePlus

    ... course of ALS. ALS also will require some adaptations to your environment, both for safety and to ... the way, Chapter 6 will include information on adaptations for computer access. Though the chapter is called “ ...

  4. 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 ...

  5. 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.

  6. Photoelectrical, photophysical and photocatalytic properties of Al based MOFs: MIL-53(Al) and MIL-53-NH2(Al)

    NASA Astrophysics Data System (ADS)

    An, Yang; Li, Huiliang; Liu, Yuanyuan; Huang, Baibiao; Sun, Qilong; Dai, Ying; Qin, Xiaoyan; Zhang, Xiaoyang

    2016-01-01

    Two Al based MOFs (MIL-53(Al) and MIL-53-NH2 (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 AlO6-octahedra, which not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activity of Al based MOFs.

  7. 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 to 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Immunomodulatory drugs in AL amyloidosis.

    PubMed

    Jelinek, T; Kufova, Z; Hajek, R

    2016-03-01

    Immunoglobulin light chain amyloidosis (AL amyloidosis) is indeed a rare plasma cell disorder, yet the most common of the systemic amyloidoses. The choice of adequate treatment modality is complicated and depends dominantly on the risk stratification of these fragile patients. Immunomodulatory drugs (IMiDs) are currently used in newly diagnosed patients as well as in salvage therapy in relapsed/refractory patients. IMiDs have a pleiotropic effect on malignant cells and the exact mechanism of their action has been described recently. Thalidomide is the most ancient representative, effective but toxic. Lenalidomide seems to be more effective, nevertheless the toxicity remains high, especially in patients with renal insufficiency. Pomalidomide is the newest IMiD used in this indication with a good balance between efficacy and tolerable toxicity and represents the most promising compound. This review is focused on the evaluation of all three representatives of IMiDs and their roles in the treatment of this malignant disorder. PMID:26806146

  13. 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.

  14. 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.

  15. Reactive Plasma Spraying of Fine Al2O3/AlN Feedstock Powder

    NASA Astrophysics Data System (ADS)

    Shahien, Mohammed; Yamada, Motohiro; Yasui, Toshiaki; Fukumoto, Masahiro

    2013-12-01

    Reactive plasma spraying (RPS) is a promising technology for in situ formation of aluminum nitride (AlN) coatings. Recently, AlN-based coatings were fabricated by RPS of alumina (Al2O3) powder in N2/H2 thermal plasma. This study investigated the feasibility of RPS of a fine Al2O3/AlN mixture and the influence of the plasma gases (N2, H2) on the nitriding conversion, and coating microstructure and properties. Thick AlN/Al2O3 coatings with high nitride content were successfully fabricated. The coatings consist of h-AlN, c-AlN, Al5O6N, γ-Al2O3, and a small amount of α-Al2O3. Use of fine particles enhanced the nitriding conversion and the melting tendency by increasing the surface area. Furthermore, the AlN additive improved the AlN content in the coatings. Increasing the N2 gas flow rate improved the nitride content and complete crystal growth to the h-AlN phase, and enhanced the coating thickness. On the other hand, though the H2 gas is required for plasma nitriding of the Al2O3 particles, increasing its flow rate decreased the nitride content and the coating thickness. Remarkable influence of the plasma gases on the coating composition, microstructure, and properties was observed during RPS of the fine particles.

  16. Al/Al-N/AlN compositional gradient film synthesized by ion-beam assisted deposition method

    SciTech Connect

    Amamoto, Yoshiki; Uchiyama, Shingo; Watanabe, Yoshihisa; Nakamura, Yoshikazu

    1997-12-01

    Al/Al-N-AlN compositional gradient thin film was deposited on a Si(100) substrate at room temperature by ion-beam assisted deposition method, with a diminishing ion beam current from 1.4 to 0 mA at increments of 0.3 mA in order to gradually decrease the nitrogen to aluminum ratio at the substrate. The gradual Al and AlN variation in composition was shown by the change of the Al/N atomic ratio analyzed by the energy dispersive X-ray spectroscopy (EDX) and the X-ray photoelectron spectroscopy (XPS) in the cross section of the film. The formation of crystalline Al metal and AlN ceramic layer on the Si substrate was revealed by X-ray diffraction (XRD). The cross sectional image taken by high resolution transmission electron microscope (HRTEM) showed a nano-sized crystalline Al-N ceramic material and the flat interface between the Si substrate and the AlN film.

  17. Accumulation of Al in Root Mucilage of an Al-Resistant and an Al-Sensitive Cultivar of Wheat.

    PubMed Central

    Archambault, D. J.; Zhang, G.; Taylor, G. J.

    1996-01-01

    To estimate rates of Al accumulation within the symplasm, all apoplastic pools of Al need to be eliminated or accounted for. We have developed a revised kinetic protocol that allows us to estimate the contribution of mucilage-bound Al to total, nonexchangeable Al, and to eliminate the mucilage as an apoplastic pool of Al. By comparing the Al content of excised root tips (2 cm) of wheat (Triticum aestivum L.) with and without the removal of the mucilage (using a 10-min wash in 1 M NH4Cl), we found that Al bound to the mucilage accounted for approximately 25 to 35% of Al remaining after desorption in citric acid. The kinetics of Al uptake into mucilage were biphasic, with a rapid phase occurring in the first 30 min of uptake, followed by a linear phase occurring in the remainder of the experimental period (180 min). By adopting a step for removal of mucilage into our existing kinetic protocol, we have been able to isolate a linear phase of uptake with only a slight deviation from linearity in the first 5 min. Although we cannot unambiguously identify this phase of uptake as uptake into the symplasm, we believe this new protocol provides us with the most accurate quantitative estimate of symplastic Al yet available. PMID:12226458

  18. Esperanzaite, NaCa(2)Al(2)(As(5+)O(4))[As(5+)O(3)(OH)](OH)(2)F(4)(H(2)O), A New Mineral From Mina La Esperanza, Mexico: Descriptive Mineralogy and Atomic Arrangement

    SciTech Connect

    Cureton, F.; Falster, A.U.; Foord, E.E.; Hlava, P.F.; Hughes, J.M.; Maxwell, C.H.

    1998-11-09

    Esperanzaite, ideally NaCazA12(As5+0.i)[As5+03 (OH)] (OH)2FJH20), Z =2, is a new mineral from the Mina h Esperarq Durango State, Mexico. The mineral occurs as blue-green botryoidal crystalline masses on rhyolite, with separate spheres up to 1.5 mm Y Deceased in diameter. Mobs hardness is 4.5, specific gravity 3.240h, and 3.36( 3)C.IC. Optical properties were measured in 589 nm light. Esperanzaite is biaxial (-), .Y= Y = Z= colorless, a 1.580(1), ~ 1.588( 1), and y 1.593(1 ); 2V0hs is 74(1 ~ and 2 }'CUIC is 76.3". Dispersion is medium, r < v, and optic axes are oriented as a A Z = +50.5o, b = Y, c P. X = +35". The five strongest X-ray diffraction maxima in the powder pattern are (~ /, hk~: 2.966,100, 13 i, 31 i, 031 ; 3.527,90, 220; 2.700,90,221,002, 040; 5.364>80, 001, 020; 4.796,80,011. Esperanzaite is monoclinic, u 9.687(5), b 10.7379(6), c 5.5523(7)& ~ 105.32( 1 )", space group P21/nz. The atomic arrangement of esperanzaite was solved by Direct Methods and Fourier analysis (R= 0.03 1). The Fundamental Building Block is formed of stacks of heteropolyhedral tetramers; the tetramers are formed of two arsenate tetrahedral and two Al octahedra, comer-linked in 4-member rings. The Fundamental Building Blocks are linked by irregular lda~j and Ca@ polyhedra.

  19. Fabrication of Nb/AlO x/Al/AlO x/Nb junctions for voltage standard applications

    NASA Astrophysics Data System (ADS)

    Maezawa, M.; Urano, C.; Kaneko, N.; Kiryu, S.

    2007-10-01

    We present an overdamped superconductor-insulator-normal-insulator-superconductor (SINIS) junction technology for ac voltage standard applications. Modifying our standard Nb-junction process, we developed a simple process for Nb/AlOx/Al/AlOx/Nb-junction circuits. A Josephson arbitrary waveform synthesizer device which consisted of a 100-SINIS-junction array embedded in a 50 Ω coplanar waveguide was fabricated and successfully tested.

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

    SciTech Connect

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; Liu, Xiang -Yang; Misra, Amit

    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.

  1. Growth and Stress-induced Transformation of Zinc blende AlN Layers in Al-AlN-TiN Multilayers

    PubMed Central

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; Liu, Xiang-Yang; Misra, Amit

    2015-01-01

    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. PMID:26681109

  2. Growth and Stress-induced Transformation of Zinc blende AlN Layers in Al-AlN-TiN Multilayers.

    PubMed

    Li, Nan; Yadav, Satyesh K; Wang, Jian; Liu, Xiang-Yang; Misra, Amit

    2015-01-01

    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. PMID:26681109

  3. Reply to Vance et al.

    SciTech Connect

    Woon-Chee Yee; Elliott, J.L; Kwon, J.M.; Goodfellow, P.

    1996-07-01

    In our report of a family with a motor and sensory polyneuropathy that was linked to chromosome 3q, we classified this neuropathy as a form of hereditary motor and sensory neuropathy II (HMSN II, also known as {open_quotes}CMT2{close_quotes}). Doubts have been raised by Vance et al. as to whether this neuropathy should be classified as hereditary sensory autonomic neuropathy I (HSAN I) instead of HMSN II. While it is reasonable to raise such doubts, we believe that the neuropathy is best designated as HMSN II for the reasons described below. The group of disorders described as HSAN are characterized by primary or predominant involvement of sensory and autonomic neurons that fail to develop or that undergo atrophy and degeneration. These disorders were extensively reviewed by Dyck and Ohta, who initially described them as the hereditary sensory neuropathies (HSN). It was Dyck who subsequently suggested that these disorders be designated HSAN rather than HSN, because of the presence of autonomic involvement. 8 refs.

  4. 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.

  5. 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

  6. 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.

  7. A New Phase in ALS Research.

    PubMed

    Chong, P Andrew; Forman-Kay, Julie D

    2016-09-01

    In this issue of Structure, Conicella et al. (2016) present evidence that the low complexity C-terminal region of TDP-43 undergoes liquid-liquid phase separation. ALS-associated mutations alter this phase separation process, providing a possible mechanism for the pathology caused by these TDP-43 mutations. The work is strongly supportive of toxic loss of RNA processing function in ALS. PMID:27602988

  8. Memory deficits and retrieval processes in ALS.

    PubMed

    Mantovan, M C; Baggio, L; Dalla Barba, G; Smith, P; Pegoraro, E; Soraru', G; Bonometto, P; Angelini, C

    2003-05-01

    Subtle neuropsychological deficits have been described in patients affected by amyotrophic lateral sclerosis (ALS) without dementia. Overall, selective impairment in memory function has been reported, but the source of memory impairment in ALS has yet to be defined. We performed neuropsychological screening in 20 ALS patients. Semantic encoding and post-encoding cue effects on the retrieval of word lists were investigated in the ALS patients and normal controls. Severity of memory impairment was correlated to cerebral blood perfusion detected by single photon emission computed tomography (SPECT). ALS patients showed moderate impairments in frontal and memory tests. Short-term memory was normal, while serial position retrieval of word lists with normal recency effect but poor primacy effect showed long-term memory deficit. ALS patients performed better in cued encoding than in cued post-encoding recall condition. In the cued post-encoding condition, the primacy effect in word list recall improved significantly in controls, but not in ALS patients, as compared with both the free recall and cued encoding conditions. SPECT hypoperfusion was observed in frontal and temporal areas in ALS patients. ALS patients showed a long-term memory deficit which did not improve in cued post-encoding condition as it does for controls. We hypothesize abnormal retrieval processes related to frontal lobe dysfunction which entails difficulties in generating stable long-memory traces at encoding. PMID:12752394

  9. Interfacial Phenomena in Al/Al, Al/Cu, and Cu/Cu Joints Soldered Using an Al-Zn Alloy with Ag or Cu Additions

    NASA Astrophysics Data System (ADS)

    Pstruś, Janusz; Gancarz, Tomasz

    2014-05-01

    The studies of soldered joints were carried out in systems: Al/solder/Al, Al/solder/Cu, Cu/solder/Cu, where the solder was (Al-Zn)EUT, (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Ag and (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Cu addition. Brazing was performed at 500 °C for 3 min. The EDS analysis indicated that the composition of the layers starting from the Cu pad was CuZn, Cu5Zn8, and CuZn4, respectively. Wetting tests were performed at 500 °C for 3, 8, 15, and 30 min, respectively. Thickness of the layers and their kinetics of growth were measured based on the SEM micrographs. The formation of interlayers was not observed from the side of Al pads. On the contrary, dissolution of the Al substrate and migration of Al-rich particles into the bulk of the solder were observed.

  10. Al-doped ZnO nanocrystals

    NASA Astrophysics Data System (ADS)

    Kadam, Pratibha; Agashe, Chitra; Mahamuni, Shailaja

    2008-11-01

    Al3+-doped ZnO nanocrystals were differently obtained by wet chemical and an electrochemical route. An increase in forbidden gap due to change in crystal size and also due to Al3+ doping in ZnO is critically analyzed. The Moss-Burstein type shift in Al3+-doped ZnO nanocrystals provides an evidence of successful Al3+ doping in ZnO nanocrystals. The possibility of varying the carrier concentration in ZnO nanocrystals is the indirect implication of the present investigations.

  11. Genetics of Familial and Sporadic ALS

    ClinicalTrials.gov

    2016-03-21

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

  12. 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.

  13. Effects of the Al content on pore structures of porous TieAl alloys

    SciTech Connect

    Jiang, Y; He, Y H; Zou, J; Huang, B; Liu, C

    2008-01-01

    PorousTi Alalloys with different nominal compositions were fabricated through a reactive synthesis of Ti and Al elemental powders. It has been found that the pore parameters vary with the Al contents, indicating that the nature of the pores can be manipulated through changing the Al contents. In addition, detailed structural characterizations showed that the fabricated porousTi Alalloys can have three crystalline phases (i.e., 2-Ti3Al, -TiAl, and TiAl3) when using different compositions. The fundamental reasons behind these phenomena have been explored.

  14. Response to Signorovitch et al.

    PubMed

    Flot, Jean-François; Debortoli, Nicolas; Hallet, Bernard; Van Doninck, Karine

    2016-08-22

    Signorovitch et al.[1] comment that an Oenothera-like meiosis [2] could produce a pattern similar to what we observed in our study of natural isolates of the bdelloid rotifer Adineta vaga, which we attributed to horizontal gene transfers (HGTs) [3]. Indeed, our HGT hypothesis appears at first sight difficult to conciliate with their observation of a congruent pattern of allele sharing at four large loci possibly located on different chromosomes [4]. However, one might imagine conditions under which massive horizontal gene transfer between bdelloid individuals could produce such a pattern, notably if the individuals involved had previously lost most of their heterozygosity because of their exposure to frequent desiccation (which produces DNA double-strand breaks [5]). In the published A. vaga genome the loss of heterozygosity due to large-scale gene conversion events or break-induced replication covers only about 10% of the genome [6], but this percentage may be much higher in environmental isolates that often experience dessication. Besides, if an Oenothera-like mode of meiosis occurs in bdelloids frequently enough to be detected in a single sampling of 29 individuals (as in [4]), one would expect males and meiosis to be observed at least occasionally, and instances of congruent allele sharing across loci should turn up frequently in genetic surveys. This was not the case in [3]: among the 82 A. vaga individuals sequenced for four nuclear markers, no trio of individuals presented congruent patterns of shared sequences at different loci. For these reasons, and in the absence of any direct evidence for an Oenothera-like meiosis in bdelloids, we still consider inter-bdelloid HGTs a more parsimonious explanation for our results. PMID:27554651

  15. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions

    NASA Astrophysics Data System (ADS)

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-07-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits.

  16. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions

    PubMed Central

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-01-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits. PMID:27403611

  17. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions.

    PubMed

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-01-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits. PMID:27403611

  18. 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.

  19. 76 FR 18783 - United States et al.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-05

    ... Antitrust Division United States et al. v. Dean Foods Company; Proposed Final Judgment, Stipulation and... of America, et al. v. Dean Foods Company, Civil Action No. 2:10-cv-00059 (JPS). On January 22, 2010, the United States and its co-plaintiffs filed a Complaint alleging that Dean Foods...

  20. 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…

  1. 75 FR 62858 - United States, et al.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-13

    ... Antitrust Division United States, et al. v. American Express Company, et al.; Proposed Final Judgment and... been filed with the United States District Court for the Eastern District of New York in United States..., 2010, the United States and seven States filed a Complaint alleging that certain rules, policies,...

  2. A look at dairy mob grazing in the Northeast

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proponents of ultra-high stocking density (UHSD) grazing emphasize increased forage use efficiency and soil improvement by grazing mature forage with stocking densities up to 560,425 kg/ha of beef cattle on small paddocks with rest periods up to 125 days. However, it is unclear if this management te...

  3. [A case report on mobbing in a school child].

    PubMed

    Holtz, S

    2012-08-01

    Forty percent of the work of a paediatrician in private practice consists of counselling parents and children. There is a danger that behavioural symptoms are not taken seriously and brushed away with simple advices. This case vignette demonstrates that difficult and complex symptoms can be solved by using a concept-oriented approach. PMID:22851462

  4. The Problem of Mobbing in a College Department

    ERIC Educational Resources Information Center

    Druzhilov, S. A.

    2012-01-01

    The phenomenon of harassment in Russian universities creates an environment that can be both threatening to the individual and a source of poor performance by the work group. Policies need to be developed to deal with this destructive form of behavior. [This article was translated by Kim Braithwaite.

  5. [Mobbing and violence at school. Trends from 2002 to 2010].

    PubMed

    Melzer, W; Oertel, L; Ottova, V

    2012-07-01

    The purpose of this study was to undertake an assessment and differentiated examination of the development of bullying and violence in schools between 2002 and 2010 in Germany.We examined the national German data of Health Behaviour in School-aged Children (HBSC) study in 2002, 2006 and 2010. A paper-pencil questionnaire was distributed to a representative sample (N=17 929) of 11-, 13- and 15-year-old school children. The evaluation of the data was done by descriptive statistics and logistic regression analyses, controlled by age, gender, family affluence, school type and survey year.A clear positive trend could be identified: from 2002 to 2010 the number of bullies and bully victims decreased whereas the group of the uninvolved pupils increased. There was a delay in this trend for children with low family affluence.The obvious success in the prevention of violence is shown by the decreasing rate of bullies. The paper discusses whether future prevention should focus more on victims and children with educationally deprived background. PMID:22836896

  6. 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

  7. Characteristics of heat resistant alloys Ti10Nb45Al and Ti18Nb48Al

    SciTech Connect

    Weijun Zhang; Guoliang Chen; Yandong Wang; Zuqing Sun )

    1993-05-01

    Based on a systematic study of the ternary Ti-Nb-Al system, two attractive heat resistant alloys, Ti10Nb45Al and Ti18Nb48Al, were developed, and the characteristics of these alloys were discussed: (1) After annealing at 1,200 C for 240 h and furnace cooling to room temperature, the Ti10Nb45Al alloy exhibits an [alpha][sub 2] + [gamma] lamellar microstructure, and the Ti18Nb48Al alloy shows a plate-like structure consisting of [alpha][sub 2], [gamma] and [gamma][sub 1] phases. (2) The specific strengths of Ti10Nb45Al and Ti18Nb48Al are much higher than TiAl and superalloys in the temperature range of 800 [approximately] 1,100 C. The compressive yield strengths of these alloys are on the order of 700 MPa at 800 C and 350 MPa at 1,100 C. The density of these alloys is about 4.3 g/cm[sup 3]. (3) The annealed Ti10Nb45Al and Ti18Nb48Al exhibit some ductility at room temperature, with the compressive elongation on the order of 12% and the fracture toughness as high as 16 MPa[radical]m. The ductile-brittle transformation temperatures for Ti10Nb45Al and Ti18Nb48Al are 650 C and 750 C, respectively. (4) The parabolic constant K[sub p] for oxidation of Ti10Nb45Al and Ti18Nb48Al are 0.88 and 0.29 mg[sup 2]cm[sup [minus]4]h[sup [minus]1] respectively, which are two orders of magnitude lower than that of TiAl and Ti[sub 3]Al alloys.

  8. 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.

  9. High temperature creep behaviour of Al-rich Ti-Al alloys

    NASA Astrophysics Data System (ADS)

    Sturm, D.; Heilmaier, M.; Saage, H.; Aguilar, J.; Schmitz, G. J.; Drevermann, A.; Palm, M.; Stein, F.; Engberding, N.; Kelm, K.; Irsen, S.

    2010-07-01

    Compared to Ti-rich γ-TiAl-based alloys Al-rich Ti-Al alloys offer an additional reduction of in density and a better oxidation resistance which are both due to the increased Al content. Polycrystalline material was manufactured by centrifugal casting. Microstructural characterization was carried out employing light-optical, scanning and transmission electron microscopy and XRD analyses. The high temperature creep of two binary alloys, namely Al60Ti40 and Al62Ti38 was comparatively assessed with compression tests at constant true stress in a temperature range between 1173 and 1323 K in air. The alloys were tested in the cast condition (containing various amounts of the metastable phases Al5Ti3 and h-Al2Ti) and after annealing at 1223 K for 200 h which produced (thermodynamically stable) lamellar γ-TiAl + r-Al2Ti microstructures. In general, already the as-cast alloys exhibit a reasonable creep resistance at 1173 K. Compared with Al60Ti40, both, the as-cast and the annealed Al62Ti38 alloy exhibit better creep resistance up to 1323 K which can be rationalized by the reduced lamella spacing. The assessment of creep tests conducted at identical stress levels and varying temperatures yielded apparent activation energies for creep of Q = 430 kJ/mol for the annealed Al60Ti40 alloy and of Q = 383 kJ/mol for the annealed Al62Ti38 material. The latter coincides well with that of Al diffusion in γ-TiAl, whereas the former can be rationalized by the instability of the microstructure containing metastable phases.

  10. 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.

  11. 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

  12. Al-Akhawayni's description of pulmonary circulation.

    PubMed

    Yarmohammadi, Hassan; Dalfardi, Behnam; Rezaian, Jafar; Ghanizadeh, Ahmad

    2013-10-01

    Since antiquity, heart function and the mechanism of blood circulation within the human body have been the focus of attention of scientists from different parts of the world. Over the passage of time, the theories and works of these scientists have resulted in the achievement of today's knowledge of circulation. The medieval Persian scholar, Al-Akhawayni Bukhari (?-983AD), is among the physicians who investigated both the anatomy and the physiology of the human body. Al-Akhawayni describes the mechanism of pulmonary circulation in his only extant book, "Hidayat al-Muta`llemin fi al-Tibb" (A Scholar's Guide to Medicine) with which he made a contribution to the development of knowledge regarding this mechanism in the medicine of the Islamic world. In this paper, Al-Akhawayni's viewpoints on anatomy and the function of the heart, its related vessels, and also pulmonary circulation will be briefly discussed. PMID:23890868

  13. Opportunities for improving therapy development in ALS.

    PubMed

    Bruijn, Lucie; Cudkowicz, Merit

    2014-06-01

    In May 2013, The ALS Association and The Northeast ALS Consortium (NEALS) convened a meeting of stakeholders for a round-table discussion of ways to improve therapy development in ALS. The following overview summarizes issues raised and potential new directions discussed at the meeting. We recommend that future phase II clinical trials in ALS proceed when the proposed treatment is directed at targets that are likely to be involved in ALS pathogenesis in a defined subgroup of patients, and be accompanied by one or more biomarkers to track both clinical progression and pharmacodynamic engagement of the target. Innovations in trial structure and design, and greater involvement of patient advocates, may also improve trials. PMID:24472060

  14. AL(0) in municipal waste incinerator ash

    NASA Astrophysics Data System (ADS)

    Stipp, S. L.; Ronsbo, J. G.; Zunic, T. B.; Christensen, T. H.

    2003-04-01

    Disposal of municipal waste is a challenge to society. Waste volume is substantially decreased by incineration but residual ash usually contains a number of toxic components which must be immobilised to insure environmental protection. One element, chromium, is mobile and toxic in its oxidised state as Cr(VI) but it can be reduced to Cr(III) and immobilised. Reduction can be promoted by ash treatment with Fe(0) or Fe(II), but recent evidence shows that at least some Cr(VI) is reduced spontaneously in the ash. Aspects of ash behaviour suggest metallic aluminium as the reducing agent, but no direct evidence of Al(0) has been found until now. We examined filter ash from an energy-producing, municipal-waste incinerator (Vest-forbrænding) near Copenhagen. X-ray diffraction (XRD) identified expected salts of Na, K and Ca such as halite, sylvite, calcite, anhydrite and gypsum as well as quartz, feldspar and some hematite. Wave-dispersive electron microprobe produced elemen-tal maps of the ash; Al-rich areas were analysed quantitatively by comparison with standards. We identified metallic Al particles, averaging 50 to 100 micrometers in di-ameter, often with a fractured, glassy border of aluminum oxide. The particles were porous, explaining fast Cr(VI) reduction and they contained thin exsolution lamellae of Al-alloys of Pb and Cu or Mn, Fe and Ag, which provide clues of the Al(0) origin in the waste. Sometimes Al(0) occurred inside glassy globes of Al2O3. Time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) proved that surface Al concentrations on ash particles were below detection, confirming reactivity of the Al(0) bulk. The persistence of reduced Al through the highly oxidising combustion procedure comes as a surprise and is a benefit in the immobilisation of Cr(VI) from municipal-waste incineration residues.

  15. 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. PMID:27423564

  16. 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.

  17. Effects of hydrogen absorption in TbNiAl and UNiAl

    SciTech Connect

    Bordallo, H.N.; Nakotte, H.; Schultz, A.; Kolomiets, A.V.; Havela, L.; Andreev, A.V.

    1998-12-31

    Although hydrides of intermetallic compounds are used extensively as hydrogen-storage media, little is known about the exact nature of metal-hydrogen interactions. However, this knowledge is of essential importance for the understanding of thermodynamics and other properties. Hydrides (deuterides) of TbNiAl and UNiAl have been widely studied because of drastic increase of magnetic ordering temperature under hydrogenation. Here the authors report neutron-diffraction results of the three deuterides, TbNiAlD{sub 1.28}, TbNiAlD{sub 0.8}a nd UNiAlD{sub 2.23}.

  18. 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.

  19. Orthorhombic aluminium oxyfluoride, AlOF.

    PubMed

    Vasiliev, Alexander D; Melnikova, Svetlana V; Isaenko, Lyudmila I

    2009-04-01

    Crystals of the title compound were extracted from the bulk of grown SrAlF(5) crystals as unexpected inclusions that were identified as the long sought after aluminium oxyfluoride. The structure of AlOF is built up from tetrahedral and octahedral polyhedra. Each tetrahedron is bisected by a mirror plane, with the Al atom and two vertex anions in the plane. All tetrahedral vertices are positions of competing oxide and fluoride ions and are shared with octahedra. These shared vertices belong to two octahedral edges which join the octahedra to form infinite zigzag chains. The chains are strung along twofold screw axes that run parallel to the unit-cell b axis. The remaining two octahedral vertices are occupied only by fluoride ions. A small deficiency in the occupation of the octahedral Al position was suggested by the refinement. However, the stoichiometry of the compound is AlOF within experimental uncertainty. The Al-F(O) distances are separated into three groups with average values of 1.652 (3) (tetrahedra), 1.800 (2) (octahedra) and 1.894 (2) A (octahedra). This structure differs widely from the reported tetragonal phase Al(1-x)O(1-3x)F(1+3x) (x = 0.0886) [Kutoglu (1992). Z. Kristallogr. 199, 197-201], which consists solely of octahedral structural units. PMID:19346595

  20. Electrical conductivity of Al-bearing bridgmanite

    NASA Astrophysics Data System (ADS)

    Yoshino, T.; Kamada, S.; Ohtani, E.; Hirao, N.

    2015-12-01

    Electrical conductivity measurements of bridgmanite with various Al contents and constant Mg# 90 at room temperature up to 2000 K and 26-28 GPa were performed in Kawai-type multianvil apparatus using impedance spectroscopic analyses. The incorporation of Al into bridgmanite significantly raises the electrical conductivity but it is small conductivity variation with respect to the amount of Al. Synchrotron Mössbauer spectroscopy of recovered samples showed a significant amount of ferric iron in aluminous bridgmanite. The mobility of charge carriers in bridgmanite was calculated from the conductivity and Fe3+/ΣFe. A relation between the logarithm of electrical conductivity and reciprocal temperature is consistent with Fe2+-Fe3+ electron hopping (small polaron) as the dominant conduction mechanism at low temperatures (< 1400 K) and ionic conduction at high temperatures (> 1600 K). Taking various conduction mechanisms into account, we develop an electrical conductivity model for aluminous bridgmanite as a function of Al and Fe content. This conductivity model suggests that the electrical conductivity of aluminous bridgmanite has a maximum at around 0.13 Al per formula unit, and further increase of Al in bridgmanite reduces the conductivity. The conductivity increase observed in the uppermost lower mantle by electromagnetic studies can be explained by increases of Fe and Na content in combination with substitution of Al into bridgmanite with increasing pressure due to the gradual decomposition of majorite garnet.

  1. Comparative study on interface and bulk charges in AlGaN/GaN metal-insulator-semiconductor heterostructures with Al2O3, AlN, and Al2O3/AlN laminated dielectrics

    NASA Astrophysics Data System (ADS)

    Zhu, Jie-Jie; Ma, Xiao-Hua; Chen, Wei-Wei; Hou, Bin; Xie, Yong; Hao, Yue

    2016-05-01

    In this paper, the interface and bulk charges in AlGaN/GaN metal-insulator-semiconductor (MIS) heterostructures with AlN, Al2O3, and Al2O3/AlN laminated dielectrics were studied. In situ plasma pretreatment resulted negligible interface trap states and voltage hysteresis. The fixed charge density at Al2O3/AlN (or Al2O3/barrier) interface was estimated to be 1.66 × 1013 cm-2 by using flat-band voltage shift, and the oxide bulk charge concentration was 2.86 × 1017 cm-3. The interface charge density at other interfaces were at the order of 1011 cm-2. Simulation results using the above charge density/concentration indicated that Al2O3/AlN interface fixed charges dominated the dielectric-related voltage shift in AlGaN/GaN MIS heterostructures, which caused a large voltage shift of -3 V with 10 nm Al2O3 thickness, while the flat-band voltage variety resulting from other types of charges was within 0.1 V.

  2. Arsenate uptake by Al nanoclusters and other Al-based sorbents during water treatment.

    PubMed

    Mertens, Jasmin; Rose, Jérôme; Wehrli, Bernhard; Furrer, Gerhard

    2016-01-01

    In many parts of the world, arsenic from geogenic and anthropogenic sources deteriorates the quality of drinking water resources. Effective methods of arsenic removal include adsorption and coagulation with iron- and aluminum-based materials, of which polyaluminum chloride is widely employed as coagulant in water treatment due to its low cost and high efficiency. We compared the arsenic uptake capacity and the arsenic bonding sites of different Al-based sorbents, including Al nanoclusters, polyaluminum chloride, polyaluminum granulate, and gibbsite. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that As(V) forms bidentate-binuclear complexes in interaction with all Al-based removal agents. The octahedral configuration of nanoclusters and the distribution of sorption sites remain the same in all types of removal agents consisting of nano-scale Al oxyhydroxide particles. The obtained distances for As(V)-O and As(V)-Al agreed with previously published data and were found to be 1.69 ± 0.02 Å and 3.17-3.21 Å, respectively. Our study suggests that As(V) binds to Al nanoclusters as strongly as to Al oxide surfaces. The As sorption capacity of Al nanoclusters was found to be very similar to that of Al clusters in a polyaluminum chloride. The most efficient Al-based sorbents for arsenic removal were Al nanoclusters, followed by polyaluminum granulate. PMID:26613179

  3. Hybrid Al + Al3Ni metallic foams synthesized in situ via laser engineered net shaping

    NASA Astrophysics Data System (ADS)

    Zheng, Baolong; Li, Ying; Smugeresky, John E.; Zhou, Yizhang; Baker, Dean; Lavernia, Enrique J.

    2011-09-01

    A hybrid, Al + Al3Ni metallic foam was synthesized in situ via laser engineered net shaping (LENS®) of Ni-coated 6061 Al powder in the absence of a foaming agent. During LENS® processing, the Ni coating reacted with the Al matrix, resulting in the simultaneous formation of a fine dispersion of Al3Ni, and a high volume fraction of porosity. As a reinforcement phase, the intermetallic compound formed particles with a size range of 1-5 µm and a volume fraction of 63%, with accompanying 35-300 µm pores with a 60% volume fraction. The microstructure of the as-deposited Al + Al3Ni composite foams was characterized using SEM, EDS, XRD and TEM/HRTEM techniques. The evolution of the microstructure was analyzed on the basis of the thermal field present during deposition, paying particular attention to the thermodynamics of the Al3Ni intermetallic compound formation as well as discussing the mechanisms that may be responsible for the observed porosity. The mechanical behavior of the as-deposited material was characterized using compression and microhardness testing, indicating that the yield strength and hardness are 190 MPa and 320 HV, respectively, which represents an increase of over three times higher than that of annealed Al6061, or similar to heat-treated Al6061 fully dense matrix, and much higher than those of traditional Al alloy foams, and with a low density of 1.64 g/m3.

  4. Optical characterization of Al- and N-polar AlN waveguides for integrated optics

    NASA Astrophysics Data System (ADS)

    Rigler, Martin; Buh, Jože; Hoffmann, Marc P.; Kirste, Ronny; Bobea, Milena; Mita, Seiji; Gerhold, Michael D.; Collazo, Ramon; Sitar, Zlatko; Zgonik, Marko

    2015-04-01

    Dispersion of the extraordinary and ordinary refractive indices of Al- and N-polar AlN waveguides is measured by multiple angle-of-incidence and spectroscopic ellipsometry techniques. The polarity-controlled AlN layers are grown by metal-organic chemical vapor deposition on (0001)-sapphire substrates. Taking into consideration the different surface morphologies of the Al- and N-polar AlN waveguides, we propose two optical models to describe the measured ellipsometry data. The results indicate that there is no difference between the refractive indices of the AlN grown in opposite directions, which confirms the potential of the AlN lateral polar structures for use in nonlinear optical applications based on quasi phase matching.

  5. A Rechargeable Al/S Battery with an Ionic-Liquid Electrolyte.

    PubMed

    Gao, Tao; Li, Xiaogang; Wang, Xiwen; Hu, Junkai; Han, Fudong; Fan, Xiulin; Suo, Liumin; Pearse, Alex J; Lee, Sang Bok; Rubloff, Gary W; Gaskell, Karen J; Noked, Malachi; Wang, Chunsheng

    2016-08-16

    Aluminum metal is a promising anode material for next generation rechargeable batteries owing to its abundance, potentially dendrite-free deposition, and high capacity. The rechargeable aluminum/sulfur (Al/S) battery is of great interest owing to its high energy density (1340 Wh kg(-1) ) and low cost. However, Al/S chemistry suffers poor reversibility owing to the difficulty of oxidizing AlSx . Herein, we demonstrate the first reversible Al/S battery in ionic-liquid electrolyte with an activated carbon cloth/sulfur composite cathode. Electrochemical, spectroscopic, and microscopic results suggest that sulfur undergoes a solid-state conversion reaction in the electrolyte. Kinetics analysis identifies that the slow solid-state sulfur conversion reaction causes large voltage hysteresis and limits the energy efficiency of the system. PMID:27417442

  6. Oxidation of Al2O3 continuous fiber-reinforced/NiAl composites

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Nesbitt, J. A.; Noebe, R. D.; Bowman, R. R.

    1992-01-01

    The 1200 C and 1300 C isothermal and cyclic oxidation behavior of Al2O3 continuous fiber-reinforced/NiAl composites were studied. Oxidation resulted in formation of Al2O3 external scales in a similar manner as scales formed on monolithic NiAl. The isothermal oxidation of an Al2O3/NiAl composite resulted in oxidation of the matrix along the fiber/matrix interface near the fiber ends. This oxide acted as a wedge between the fiber and the matrix, and, under cyclic oxidation conditions, led to further oxidation along the fiber lengths and eventual cracking of the composite. The oxidation behavior of composites in which the Al2O3 fibers were sputter coated with nickel prior to processing was much more severe. This was attributed to open channels around the fibers which formed during processing, most likely as a result of the diffusion of the nickel coating into the matrix.

  7. High performance AlGaN/GaN HEMTs with AlN/SiNx passivation

    NASA Astrophysics Data System (ADS)

    Xin, Tan; Yuanjie, Lü; Guodong, Gu; Li, Wang; Shaobo, Dun; Xubo, Song; Hongyu, Guo; Jiayun, Yin; Shujun, Cai; Zhihong, Feng

    2015-07-01

    AlGaN/GaN high electron-mobility transistors (HEMTs) with 5 nm AlN passivation by plasma enhanced atomic layer deposition (PEALD) were fabricated, covered by 50 nm SiNx which was grown by plasma enhanced chemical vapor deposition (PECVD). With PEALD AlN passivation, current collapse was suppressed more effectively and the devices show better subthreshold characteristics. Moreover, the insertion of AlN increased the RF transconductance, which lead to a higher cut-off frequency. Temperature dependence of DC characteristics demonstrated that the degradations of drain current and maximum transconductance at elevated temperatures for the AlN/SiNx passivated devices were much smaller compared with the devices with SiNx passivation, indicating that PEALD AlN passivation can improve the high temperature operation of the AlGaN/GaN HEMTs. Project supported by the National Natural Science Foundation of China (No. 60890192).

  8. Ni{sub 3}Al aluminide alloys

    SciTech Connect

    Liu, C.T.

    1993-10-01

    This paper provides a brief review of the recent progress in research and development of Ni{sub 3}Al and its alloys. Emphasis has been placed on understanding low ductility and brittle fracture of Ni{sub 3}Al alloys at ambient and elevated temperatures. Recent studies have resulted in identifying both intrinsic and extrinsic factors governing the fracture behavior of Ni{sub 3}Al alloys. Parallel efforts on alloy design using physical metallurgy principles have led to properties for structural use. Industrial interest in these alloys is high, and examples of industrial involvement in processing and utilization of these alloys are briefly mentioned.

  9. Suspected variables among Al Sufi stars.

    NASA Astrophysics Data System (ADS)

    Hoffleit, D.

    In the tenth century Al Sufi compiled a catalogue of some 1100 stars. J.E. Gore, around 1900, wrote extensively on the magnitudes of these stars. On intercomparing them with a few other catalogues, Gore surmised that some 38 stars appeared to show secular variations. Here all the Al Sufi magnitudes have been compared with numerous additional sources, but smooth secular variations are not substantiated although some stars seem to have undergone comparatively sudden changes after about 1600. About 70 Al Sufi stars are now named or suscpected variable stars, but nearly all with amplitudes under 0.3 V.

  10. Characterization of AlInN/AlN/GaN Heterostructures with Different AlN Buffer Thickness

    NASA Astrophysics Data System (ADS)

    Çörekçi, S.; Dugan, S.; Öztürk, M. K.; Çetin, S. Ş.; Çakmak, M.; Özçelik, S.; Özbay, E.

    2016-05-01

    Two AlInN/AlN/GaN heterostructures with 280-nm- and 400-nm-thick AlN buffer grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD) have been investigated by x-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) and Hall-effect measurements. The symmetric (0002) plane with respect to the asymmetric (10bar{1} 2) plane in the 280-nm-thick AlN buffer has a higher crystal quality, as opposed to the 400-nm-thick buffer. The thinner buffer improves the crystallinity of both (0002) and (10bar{1} 2) planes in the GaN layers, it also provides a sizeable reduction in dislocation density of GaN. Furthermore, the lower buffer thickness leads to a good quality surface with an rms roughness of 0.30 nm and a dark spot density of 4.0 × 108 cm-2. The optical and transport properties of the AlInN/AlN/GaN structure with the relatively thin buffer are compatible with the enhancement in its structural quality, as verified by XRD and AFM results.

  11. Characterization of AlInN/AlN/GaN Heterostructures with Different AlN Buffer Thickness

    NASA Astrophysics Data System (ADS)

    Çörekçi, S.; Dugan, S.; Öztürk, M. K.; Çetin, S. Ş.; Çakmak, M.; Özçelik, S.; Özbay, E.

    2016-07-01

    Two AlInN/AlN/GaN heterostructures with 280-nm- and 400-nm-thick AlN buffer grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD) have been investigated by x-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) and Hall-effect measurements. The symmetric (0002) plane with respect to the asymmetric (10bar{1}2) plane in the 280-nm-thick AlN buffer has a higher crystal quality, as opposed to the 400-nm-thick buffer. The thinner buffer improves the crystallinity of both (0002) and (10bar{1}2) planes in the GaN layers, it also provides a sizeable reduction in dislocation density of GaN. Furthermore, the lower buffer thickness leads to a good quality surface with an rms roughness of 0.30 nm and a dark spot density of 4.0 × 108 cm-2. The optical and transport properties of the AlInN/AlN/GaN structure with the relatively thin buffer are compatible with the enhancement in its structural quality, as verified by XRD and AFM results.

  12. Diffusion at the Al/Al oxide interface during electromigration in wide lines

    NASA Astrophysics Data System (ADS)

    Augur, R. A.; Wolters, R. A. M.; Schmidt, W.; Dirks, A. G.; Kordić, S.

    1996-03-01

    Significant large-scale modification of the surface of Al-Si conductors was observed, due to electromigration in wide lines and under low stress conditions. After electromigration stressing the Al layers showed local thickness variations, i.e., damage by thinning. The mechanism underlying this damage causes substantial metal transport. Nevertheless, damage by thinning has received little attention in the past. Thinning was observed: (1) in a number of different alloys (Al-Si, Al-Cu, Al-Si-V, and Al-Si-V-Pd), (2) with a number of different underlayers [SiO2, W-Ti (no vacuum break after Al deposition) and W-Ti (oxidized surface before Al deposition)], (3) over an extended temperature range, (4) over a range of current density, and (5) in structures with and without passivation. The results show that thinning is a general phenomenon. An activation energy of approximately 0.5 eV was determined for the temperature dependence of a combined mechanism of concurrent thinning plus voiding in Al99Si1. Several alternatives are examined to explain the observations, namely mass movement along dislocations, Al bulk diffusion, and diffusion at the interface between the Al and its oxide. It is shown that diffusion at the Al/Al oxide interface most probably plays an important role in the damage mechanism, even under stress conditions where grain boundary diffusion is traditionally thought to dominate. Results also showed that alloying of Al with Pd can reduce the effects of damage by thinning.

  13. 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

  14. Stem Cells Deemed Safe for ALS Patients

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159627.html Stem Cells Deemed Safe for ALS Patients But further research ... June 29, 2016 (HealthDay News) -- Scientists report that stem cell therapy appears to be safe for people with ...

  15. Pesticides Linked to Raised Risk of ALS

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_158737.html Pesticides Linked to Raised Risk of ALS One toxin ... MONDAY, May 9, 2016 (HealthDay News) -- Exposure to pesticides and other chemicals may increase the risk for ...

  16. Stem Cells Deemed Safe for ALS Patients

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_159627.html Stem Cells Deemed Safe for ALS Patients But further ... June 29, 2016 (HealthDay News) -- Scientists report that stem cell therapy appears to be safe for people ...

  17. ALS and Oxidative Stress: The Neurovascular Scenario

    PubMed Central

    Thakur, Keshav; Gupta, Pawan Kumar

    2013-01-01

    Oxidative stress and angiogenic factors have been placed as the prime focus of scientific investigations after an establishment of link between vascular endothelial growth factor promoter (VEGF), hypoxia, and amyotrophic lateral sclerosis (ALS) pathogenesis. Deletion of the hypoxia-response element in the vascular endothelial growth factor promoter and mutant superoxide dismutase 1 (SOD1) which are characterised by atrophy and muscle weakness resulted in phenotype resembling human ALS in mice. This results in lower motor neurodegeneration thus establishing an important link between motor neuron degeneration, vasculature, and angiogenic molecules. In this review, we have presented human, animal, and in vitro studies which suggest that molecules like VEGF have a therapeutic, diagnostic, and prognostic potential in ALS. Involvement of vascular growth factors and hypoxia response elements also highlights the converging role of oxidative stress and neurovascular network for understanding and treatment of various neurodegenerative disorders like ALS. PMID:24367722

  18. Glial cells in ALS: the missing link?

    PubMed

    Raibon, Elsa; Todd, Lisa Marie; Möller, Thomas

    2008-08-01

    Amyotrophic lateral sclerosis (ALS) was initially known as Charcot's sclerosis, named after the French neurobiologist and physician Jean-Martin Charcot who first described this type of muscular atrophy in the early nineteenth century. In the United States, ALS became widely known as Lou Gehrig's disease after the famous baseball player who succumbed to the disease in the late 1930s. Currently, ALS is the most common motor neuron disease, with a worldwide incidence of 8 cases per 100,000 population per year. Familial forms constitute approximately 5% to 10% of all cases. Onset increases with age, with a peak in the seventh decade and a slight preponderance (relative risk, 1.3-1.5) among men compared with women. Rapid progression of motor neuron loss leads to death an average of 3 to 5 years after symptom onset. The cause of ALS remains unknown and there is still no curative therapy. PMID:18625409

  19. Thermal Conductivity of Al-Salt Composites

    NASA Astrophysics Data System (ADS)

    Li, Peng; Zhang, Mei; Wang, Lijun; Seetharaman, Seshadri

    2015-11-01

    With a view to examine the possibility of estimating the content of entrapped metallic aluminium in the salt cake from aluminium remelting, the thermal diffusivity of reference composites of KCl-NaCl-Al was measured as a function of aluminium metal content at room temperature. The thermal conductivity of the reference composites was found to increase with the metallic Al content. The lumped parameter model approach was carried out to discuss the influence of different geometry arrangements of each phase, viz. air, salts and metallic aluminium on the thermal conductivity. Application of the present results to industrial samples indicates that factors such as the interfacial condition of metallic Al particles have to be considered in order to estimate the amount of entrapped Al in the salt cake.

  20. ALS: Recent Developments from Genetics Studies.

    PubMed

    Therrien, Martine; Dion, Patrick A; Rouleau, Guy A

    2016-06-01

    Amyotrophic lateral sclerosis (ALS) is a fatal disorder that is characterized by a progressive degeneration of the upper and lower motor neurons. Most cases appear to be sporadic, but 5-10 % of cases have a family history of the disease. High-throughput DNA sequencing and related genomic capture tools are methodological advances which have rapidly contributed to an acceleration in the discovery of genetic risk factors for both familial and sporadic ALS. It is interesting to note that as the number of ALS genes grows, many of the proteins they encode are in shared intracellular processes. This review will summarize some of the recent advances and gene discovery made in ALS. PMID:27113253

  1. Pesticides Linked to Raised Risk of ALS

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_158737.html Pesticides Linked to Raised Risk of ALS One toxin ... MONDAY, May 9, 2016 (HealthDay News) -- Exposure to pesticides and other chemicals may increase the risk for ...

  2. 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.

  3. Itinerant antiferromagnetism of TiAl alloys

    NASA Astrophysics Data System (ADS)

    Petrişor, T.; Pop, I.; Giurgiu, A.; Farbaş, N.

    1986-06-01

    Magnetic susceptibility measurements of TiAl alloys are reported. Aluminium, by alloying, acts on the Néel temperature of pure titanium giving rise to a complicated phase diagram. A theoretical model, based on the itinerant antiferromagnetism model of chromium is proposed in order to explain the magnetic phase diagram of TiAl alloys. The experimental and theoretical magnetic phase diagram are in good agreement.

  4. Magnetism of Al-Mn quasicrystals

    SciTech Connect

    Liu, F.; Khanna, S.N.; Magaud, L.; Jena, P. ); de Coulon, V.; Reuse, F. ); Jaswal, S.S.; He, X. ); Cyrot-Lackman, F. )

    1993-07-01

    The effect of symmetry and concentration of Mn on the magnetism of Al-Mn quasicrystals has been investigated through self-consistent density-functional calculations using molecular clusters and supercell band-structure schemes. A single Mn atom surrounded by 54 Al atoms in an icosahedral or a cuboctahedral structure is found to be nonmagnetic. However, as the Mn concentration is increased, moments develop on Mn sites whose magnitude and coupling depend on their location.

  5. 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. PMID:26742954

  6. Metastability in the MgAl2O4-Al2O3 System

    DOE PAGESBeta

    Wilkerson, Kelley R.; Smith, Jeffrey D.; Hemrick, James G.

    2014-07-22

    Aluminum oxide must take a spinel form ( γ-Al2O3) at elevated temperatures in order for extensive solid solution to form between MgAl2O4 and α-Al2O3. The solvus line between MgAl2O4 and Al2O3 has been defined at 79.6 wt% Al2O3 at 1500°C, 83.0 wt% Al2O3 at 1600°C, and 86.5 wt% Al2O3 at 1700°C. A metastable region has been defined at temperatures up to 1700°C which could have significant implications for material processing and properties. Additionally, initial processing could have major implications on final chemistry. The spinel solid solution region has been extended to form an infinite solid solution with Al2O3 at elevatedmore » temperatures. A minimum in melting at 1975°C and a chemistry of 96 wt% Al2O3 rather than a eutectic is present, resulting in no eutectic crystal formation during solidification.« less

  7. Excitotoxicity in ALS: Overstimulation, or overreaction?

    PubMed

    King, Anna E; Woodhouse, Adele; Kirkcaldie, Matthew T K; Vickers, James C

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is an adult onset neurodegenerative disease that results in motor dysfunction and death, generally from respiratory failure. 90% of ALS cases are sporadic with no known cause. Familial cases have been linked with mutations in several disparate classes of genes, including those involved in DNA/RNA metabolism, protein misfolding, oxidative stress and the cytoskeleton, leading to the proposition that ALS could be a multi-factorial disease. However, alterations in excitability have been reported in all types of ALS cases, and may be a common disease mechanism predisposing neurons to degeneration. Excitotoxicity has long been suspected as a mediator in the disease process, and may arise from changes in synaptic inputs, or alterations in the excitability of the neurons being stimulated. Although the glutamatergic system is widely recognised as a therapeutic avenue with the potential to extend lifespan and delay disease onset, the causes of altered excitability in ALS are currently unclear and warrant further investigation. This article reviews current evidence of alterations to excitatory and inhibitory signalling in the cortex and spinal cord, and in the intrinsic excitability of motor neurons, in ALS. PMID:26584004

  8. Clinical trials for neuroprotection in ALS.

    PubMed

    Siciliano, G; Carlesi, C; Pasquali, L; Piazza, S; Pietracupa, S; Fornai, F; Ruggieri, S; Murri, L

    2010-07-01

    Owing to uncertainty on the pathogenic mechanisms underlying motor neuron degeneration in amyotrophic lateral sclerosis (ALS) riluzole remains the only available therapy, with only marginal effects on disease survival. Here we review some of the recent advances in the search for disease-modifying drugs for ALS based on their putative neuroprotective effetcs. A number of more or less established agents have recently been investigated also in ALS for their potential role in neuroprotection and relying on antiglutamatergic, antioxidant or antiapoptotic strategies. Among them Talampanel, beta-lactam antibiotics, Coenzyme Q10, and minocycline have been investigated. Progress has also been made in exploiting growth factors for the treatment of ALS, partly due to advances in developing effective delivery systems to the central nervous system. A number of new therapies have also been identified, including a novel class of compounds, such as heat-shock protein co-inducers, which upregulate cell stress responses, and agents promoting autophagy and mitochondriogenesis, such as lithium and rapamycin. More recently, alterations of mRNA processing were described as a pathogenic mechanism in genetically defined forms of ALS, as those related to TDP-43 and FUS-TLS gene mutations. This knowledge is expected to improve our understanding of the pathogenetic mechanism in ALS and developing more effective therapies. PMID:20406180

  9. Modeling of precipitation in Al alloys

    SciTech Connect

    Asta, M.; Foiles, S.M.; Wolfer, W.G.

    1996-10-01

    Objective was the development of a computational model of precipitation from a supersaturated alloy solid solution. The model is based on the formalism of chemical-reaction-rate theory combined with classical descriptions of precipitate thermodynamic properties and a mean-field treatment of diffusion-limited growht and coarsening. For the case of precipitation of Al{sub 3}Sc in supersaturated Al-Sc alloys, it is demonstrated how the model can be used to calculate number densities and size distributions of precipitates as a function of aging time and temperature, including effects of continuous cooling and thermally generated point defects. Application of the model to a specific alloy system requires knowledge of diffusion data, point defect energetics, and thermodynamic properties for bulk phases and interphase interfaces. For interfaces and point defects, thermodynamic data can be difficult to measure and reliable values of defect free energies are often unavailable. For this reason, part of the efforts were devoted to applying semiempirical and first-principles atomistic techniques to the calculation of interfacial and point-defect thermodynamic properties. This report discusses applications for interphase interfaces in the Al-Ag, Al-Sc, and Al-Li alloy systems. We also describe atomistic work aimed at understanding the energetics of vacancy clusters in Al. These clusters serve as sinks for isolated vacancies during aging and their growth can lead to more complex defects, such as dislocation loops, that act as heterogeneous nucleation sites.

  10. How common are ALS plateaus and reversals?

    PubMed Central

    Vaughan, Timothy; Wicks, Paul; Heywood, Jamie; Sinani, Ervin; Selsov, Roger; Macklin, Eric A.; Schoenfeld, David; Cudkowicz, Merit; Sherman, Alex

    2016-01-01

    Objective: To determine the frequency of amyotrophic lateral sclerosis (ALS) plateaus and reversals in the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) database. Methods: We analyzed Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) and ALSFRS–revised (ALSFRS-R) data from PRO-ACT participants. The frequencies of participants experiencing plateaus (periods where scores did not change) were calculated over 6-, 12-, and 18-month epochs. The percentage of participants ever experiencing reversals (periods where scores improved) of different lengths were also calculated and plotted. Results: Over 6 months, 25% of 3,132 participants did not decline. Over 12 months, 16% of 2,105 participants did not decline. Over 18 months, 7% of 1,218 participants did not decline. Small ALS reversals were also common, especially over shorter follow-up intervals; 14% of 1,343 participants had a 180-day interval where their ALSFRS-R slope was greater than zero. Fewer than 1% of participants ever experienced improvements of 4 or more ALSFRS-R points lasting at least 12 months. Conclusion: ALS plateaus and small reversals are common, especially over brief intervals. In light of these data, stable disease, especially for a short period of time, should not be interpreted as an ALS treatment effect. Large sustained ALS reversals, on the other hand, are rare, potentially important, and warrant further study. PMID:26658909

  11. Scattering induced by Al segregation in AlGaN/GaN heterostructures

    SciTech Connect

    Liu, Xiwen; Lu, Yanwu; Ji, Dong

    2015-08-17

    The effect of Al segregation near dislocations on the mobility of two-dimensional electron gas in AlGaN/GaN heterostructure-based high-electron-mobility transistors was investigated. Exponentially varied composition fluctuation was effective in describing Al segregation near dislocations when calculating scattering behavior. Mobility, which was limited by Al segregation surrounding dislocation lines, was calculated to be in the order of 10{sup 3} cm{sup 2}/Vs to 10{sup 6} cm{sup 2}/Vs. Results indicated that the mobility in AlGaN/GaN heterojunction was enhanced upon the reduction of dislocation density at low temperature. This study contributes to generating higher electron mobility in AlGaN/GaN heterojunctions.

  12. Thermal Properties in the MgAl2O4-Al2O3 System

    SciTech Connect

    Wilkerson, Dr. Kelley R.; Smith, Jeffrey D; Hemrick, James Gordon

    2013-01-01

    Compositional effects on the thermal diffusivity in the MgAl2O4-Al2O3 system were studied. The lowest thermal diffusivity, 0.0258 +/-5% cm/s, was measured between 79.8 and 83.9 wt% Al2O3 quenched from various temperatures between 1500 and 1700C. All of the chemistries in this range extend past the solvus, but still form a singe super-saturated spinel solid solution, regardless of quenching tempeature. A super-saturated metastable solid solution region was observed at 1500, 1600, and 1700C extending to 83.9, 85.2, and 87.1 wt% Al2O3, respectively. Beyond 83.9% Al2O3 a significant increase in thermal diffusivity, 11.7%, was observed and its attributed to precipiation of Al2O3 through spinodal decomposition.

  13. Effects of Al(III) and nano-Al13 species on malate dehydrogenase activity.

    PubMed

    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 Al(13) can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al(13) concentration increase. Our study also found that the effects of Al(III) and Al(13) 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

  14. 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.

  15. Microscopic Properties of Long-Period Ordering in Al-Rich TiAl Alloys

    NASA Astrophysics Data System (ADS)

    Hata, S.; Nakano, T.; Kuwano, N.; Itakura, M.; Matsumura, S.; Umakoshi, Y.

    2008-07-01

    The ordering mechanism of long-period superstructures (LPSs) in Al-rich TiAl alloys has been investigated by high-resolution transmission electron microscopy (HRTEM). The LPSs are classified in terms of arrangements of base clusters with different shapes and compositions formed in Ti-rich (002) layers of L10-TiAl matrix: square Ti4Al, fat rhombus Ti3Al, and lean rhombus Ti2Al type clusters. The HRTEM observations revealed that antiphase boundaries of long-range-ordered LPS domains and short-range-ordered microdomains are constructed by various space-filling arrangements of the base clusters. Such a microscopic property characterized by the base clusters and their arrangements is markedly analogous to that of the {left< {{text{1,1/2,0}}} rightrangle } * special-point ordering alloys such as Ni-Mo.

  16. Influence of RCS on Al-3Mg and Al-3Mg-0.25Sc alloys

    NASA Astrophysics Data System (ADS)

    Bhovi, Prabhakar M.; Venkateswarlu, K.

    2016-02-01

    An influence of repetitive corrugation and straightening (RCS) was studied on Al-3Mg and Al-3Mg-0.25Sc alloys up to eight passes. Each pass consist of a corrugation and followed by straightening. This has resulted in introducing large plastic strain in sample, and thus led to formation of sub-micron grain sizes with high angle grain boundaries. These sub grain formation was eventually resulted in improved mechanical properties. The average grain size of Al-3Mg-0.25Sc alloy after 8 passes yielded to ∼0.6pm. Microhardness, strength properties were evaluated and it suggests that RCS was responsible for high hardness values as compared to the as cast samples. The microhardness values after RCS were 105 HV and 130 HV for Al-3Mg and Al-3Mg-0.25Sc alloys, respectively. Similarly, ∼ 40% improvement in tensile strength from 240 MPa to 370 MPa was observed for Al- 3Mg-0.25Sc alloy after RCS process.Al-3Mg and Al-3Mg-0.25Scalloys exhibited maximum strength of 220 MPa and 370 MPa, respectively. It is concluded that RCS process has a strong influence on Al- 3Mg and Al-3Mg-0.25Sc alloys for obtaining improved mechanical properties and grain refinement. In addition to RCS process and presence of AESc precipitates in Al-3Mg-0.25Sc alloy had a significant role in grain refinement and improved mechanical properties as compared to Al-3Mg alloy.

  17. Remarks on Peinado et al.'s Analysis of J3Gen.

    PubMed

    Garcia-Alfaro, Joaquin; Herrera-Joancomartí, Jordi; Melià-Seguí, Joan

    2015-01-01

    Peinado et al. analyzed the security of the J3Gen pseudorandom number generator proposed by Melià-Seguí et al., and claimed weaknesses regarding its security properties. They also presented a deterministic attack based on the decimation of the J3Gen output sequences. We show that the assumptions made by Peinado et al. are not correct and that the proposed deterministic attack against J3Gen does not hold in practice. PMID:25781510

  18. 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)

  19. Another Security Improvement over the Lin et al.'s E-voting Scheme

    NASA Astrophysics Data System (ADS)

    Asaar, Maryam Rajabzadeh; Mohajeri, Javad; Salmasizadeh, Mahmoud

    In 2003, Lin et al. have proposed an electronic voting scheme which can be utilized in large-scale elections, and claimed it detects double voting. But in this paper, by presenting an attack, we show that voters can successfully vote more than once without being detected. Hence, we propose a new modified scheme based on the Lin et al.'s scheme with the same efficiency to solve this weakness and analyze its security.

  20. Excited states of 26Al studied via the reaction 27Al(d,t)

    NASA Astrophysics Data System (ADS)

    Srivastava, Vishal; Bhattacharya, C.; Rana, T. K.; Manna, S.; Kundu, S.; Bhattacharya, S.; Banerjee, K.; Roy, P.; Pandey, R.; Mukherjee, G.; Ghosh, T. K.; Meena, J. K.; Roy, T.; Chaudhuri, A.; Sinha, M.; Saha, A. K.; Asgar, Md. A.; Dey, A.; Roy, Subinit; Moin Shaikh, Md.

    2016-05-01

    The reaction 27Al(d,t) at 25 MeV was utilized to study the excited states of 26Al. The angular distributions of the observed excited states of 26Al were analyzed with zero range distorted wave Born approximation as well as by incorporating finite range correction parameters to extract spectroscopic factors. The two sets of extracted spectroscopic factors were compared with each other to see the effect of using finite range correction in the transfer form factor.

  1. Temperature dependence diode parameters studies of Al/CuPc/n-Si/Al structure

    NASA Astrophysics Data System (ADS)

    Kumar, Ratnesh; Kaur, Ramneek; Sharma, Mamta; Kaur, Maninder; Tripathi, S. K.

    2015-08-01

    This paper presents the fabrication of Al/CuPc/n-Si/Al metal-organic-semiconductor diode. The copper phthalocyanine as organic layer is deposited on Si substrate by thermal evaporation technique. The temperature dependent current-voltage measurements are performed on Al/CuPc/n-Si structure. The important diode parameters i.e. the barrier height and ideality factor have been calculated. The temperature dependence of barrier height and ideality factor has been studied.

  2. 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.

  3. The new structure type Gd3Ni7Al14.

    PubMed

    Pukas, Svitlana; Gladyshevskii, Roman

    2015-11-01

    The crystal structure of Gd3Ni7Al14 (trigadolinium heptanickel tetradecaaluminide) belongs to a family of two-layer structures and can be described as an assembly of interpenetrating centred straight prisms. For the Ni atoms, trigonal prisms (Al4Gd2 and Al6) are observed, the Al atoms are inside tetragonal (Ni2Al2Gd4, Ni2Al4Gd2, Al4Gd4, Ni4Al4 and Al8) and pentagonal (Ni4Al6 and Al10) prisms, while the Gd atoms are at the centres of pentagonal (Ni4Al6) and hexagonal (Ni4Al8) prisms. In each case, the true coordination polyhedron is a capped prism, also including atoms from the same layer. The structural features of Gd3Ni7Al14 are similar to those of the intermetallides PrNi2Al3 and ZrNiAl. In all these structures, Ni-centred trigonal prisms form infinite columns via common triangular faces. The columns share prism edges and form a three-dimensional framework with six-membered rings in the (001) plane in the case of the PrNi2Al3 and ZrNiAl types. In the case of Gd3Ni7Al14, six-membered rings are also observed, but only two-thirds of the rings are interconnected via prism edges. PMID:26524174

  4. Long range order and vacancy properties in Al-rich Fe{sub 3}Al and Fe{sub 3}Al(Cr) alloys

    SciTech Connect

    Kim, S.M.; Morris, D.G.

    1998-05-01

    Neutron powder diffraction measurements have been carried out in situ from room temperature to about 100 C in Fe28Al (28 at.% Al), Fe32.5Al (32.5 at.% Al) and Fe28Al15Cr (28 at.% Al, 5 at.% Cr) alloys. X-ray diffraction and TEM studies provided supporting information. The data were analyzed to obtain information about the temperature dependence of the DO{sub 3} and B2 long range order parameters, the location of the Cr atoms and their effect on the ordering energies, and on the vacancy formation and migration properties in Fe28Al and Fe32.5Al alloys. The location of the ternary alloying addition in DO{sub 3} and B2 ordered Al-rich Fe{sub 3}Al is shown to be consistent with considerations of interatomic bond energies.

  5. Strain Rates and Grain Growth in Al 5754 and Al 6061 Friction Stir Spot Welds

    NASA Astrophysics Data System (ADS)

    Gerlich, A.; Yamamoto, M.; North, T. H.

    2007-06-01

    The stir zone temperature and microstructures are compared in friction stir spot welds produced in Al 5754 and Al 6061 alloys. Electron backscattered diffraction was used to determine the relationship between tool rotation speed during welding and final stir zone grain size. Comparison of the grain sizes in rapidly quenched welds with those in air-cooled joints confirmed that grain growth occurred only in Al 6061 spot welds. There was no evidence of abnormal grain growth in the stir zones of Al 6061 welds; the final grain size could be represented using an Arrhenius equation. The strain rates during welding were determined by incorporating the stir zone temperature and average subgrain sizes in quenched spot welds in the Zener-Hollomon relation. When the tool rotation speed increased from 750 to 3000 RPM, the strain rate values ranged from 180 to 497 s-1 in Al 5754 spot welds and from 55 to 395 s-1 in Al 6061 spot welds. It is suggested that a no-slip boundary condition may be appropriate during numerical modeling of Al 5754 and 6061 friction stir spot welding. This is not the case during Al 7075, Al 2024, and Mg-alloy AZ91 spot welding because spontaneous melting facilitates slippage at the tool contact interface.

  6. 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.

  7. 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.

  8. 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. PMID:27053603

  9. HYDROGEN ADSORPTION ON β-TiAl (001) AND Ni/TiAl (001) SURFACES

    NASA Astrophysics Data System (ADS)

    Mubarak, A. A. Karim; Alelaimi, Mahmoud

    2014-04-01

    In this paper, we present first principles calculations of the energetic, electronic and magnetic properties of the variant termination of TiAl (001) and Ni/TiAl (001) surfaces with and without hydrogen atoms. The calculations have been performed within the density functional theory using full-potential linearized augmented plane wave method. The generalized gradient approximation (GGA) is utilized as the exchange-correlation energy. The octahedral site is the stable absorption site of H atom in the β-TiAl system. This absorption reduces the cohesive energy of β-TiAl system due to increase in the lattice constant. The surface energy for both TiAl (001) terminations is calculated. The stable adsorption site of H atoms on the variant termination of TiAl (001) surface is performed. The adsorption energy of hydrogen on Ti is more energetic than that on Al. The adsorption of H atom on both terminations of H/Ni/TiAl (001) is more preferable at the bridge site. The adsorption energies are enhanced on Ni atom due to the contraction between d-Ni bands and TiAl substrate band.

  10. 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.

  11. AlN/IDT/AlN/Sapphire SAW Heterostructure for High-Temperature Applications.

    PubMed

    Legrani, Ouarda; Aubert, Thierry; Elmazria, Omar; Bartasyte, Ausrine; Nicolay, Pascal; Talbi, Abdelkrim; Boulet, Pascal; Ghanbaja, Jaafar; Mangin, Denis

    2016-06-01

    Recent studies have evidenced that Pt/AlN/Sapphire surface acoustic wave (SAW) devices are promising for high-temperature high-frequency applications. However, they cannot be used above 700°C in air atmosphere as the Pt interdigital transducers (IDTs) agglomerate and the AlN layer oxidizes in such conditions. In this paper, we explore the possibility to use an AlN protective overlayer to concurrently hinder these phenomena. To do so, AlN/IDT/AlN/Sapphire heterostructures undergo successive annealing steps from 800°C to 1000°C in air atmosphere. The impact of each step on the morphology, microstructure, and phase composition of AlN and Pt films is evaluated using optical microscopy, scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), and secondary ion mass spectroscopy (SIMS). Finally, acoustical performance at room temperature of both protected and unprotected SAW devices are compared, as well as the effects of annealing on these performance. These investigations show that the use of an overlayer is one possible solution to strongly hinder the Pt IDTs agglomeration up to 1000°C. Moreover, AlN/IDT/AlN/Sapphire SAW heterostructures show promising performances in terms of stability up to 800°C. At higher temperatures, the oxidation of AlN is more intense and makes it inappropriate to be used as a protective layer. PMID:27076407

  12. Microstructure and strengthening of creep-tested cryomilled NiAl-AlN

    SciTech Connect

    Garg, A.; Whittenberger, J.D.; Luton, M.J.

    1997-12-31

    The B2 intermetallic NiAl is considered to be a prime candidate material for use as very high temperature structural components in gas turbine engines. The mechanical grinding of prealloyed NiAl powder in liquid nitrogen (cryomilling) results in an intermetallic matrix composite where micron sized particle free aluminide cores (grains) are surrounded by thin mantles comprised of nanometer sized AlN particles and NiAl grains. Under high temperature, slow strain rate conditions both compressive and tensile creep testing have shown that the mechanical strength of hot extruded cryomilled NiAl approaches the levels exhibited by advanced NiAl-based single crystals and simple Ni-based superalloys. Transmission electron microscopy of cryomilled materials tested between 1,100 and 1,300 K revealed little, if any, dislocation structure within the mantle regions, while the NiAl cores contained subgrains and dislocation networks after testing at all strain rates between 10{sup {minus}4} and 10{sup {minus}8} s{sup {minus}1}. These and other microstructural observations suggest that creep strength is the result of a fine NiAl grain/subgrain size, the inability of dislocations to move through the mantle and stabilization of the microstructure by the AlN particles.

  13. 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.

  14. Reactions of CO2 on solid and liquid Al100+.

    PubMed

    Leslie, Katheryne L; Shinholt, Deven; Jarrold, Martin F

    2013-02-14

    The reactions of CO(2) on the Al(100)(+) cluster have been investigated as a function of cluster temperature (300-1100 K) and relative kinetic energy (0.2-10 eV). Two main products are observed at low cluster temperature: Al(100)O(+) (which is believed to result from a stripping reaction) and Al(100)CO(2)(+) from complex formation. As the cluster temperature is raised, both products dissociate by loss of Al(2)O. Al(100)O(+) forms Al(98)(+), while Al(100)CO(2)(+) forms Al(98)CO(+) and Al(96)C(+). In both cases, loss of Al(2)O turns-on above the melting temperature of Al(100)(+). This presumably occurs because the overall reaction leading to the loss of Al(2)O is significantly less endothermic for the liquid cluster than for the solid. PMID:22680973

  15. Coating of a layer of Au on Al13 : The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculations

    NASA Astrophysics Data System (ADS)

    Kumar, Vijay

    2009-02-01

    We report results of ab initio pseudopotential calculations on the nanocoating of gold on an icosahedral Al13 cluster and the findings of icosahedrally symmetric endohedral Al@Al12Au20- and empty cage Al12Au202- compound fullerenes formed of metal atoms. Twelve Al atoms cap the pentagonal faces of a dodecahedral Au20 cage in which each Au atom has three Al atoms and three Au atoms as nearest neighbors. Mixing of Al13 and Au20 magic clusters leads to a large heat of formation of 0.55 eV/atom and high stability of the Al@Al12Au20 compound fullerene. The binding energies of Al12Au20 and Al@Al12Au20 are 3.017 and 3.007 eV/atom, respectively, which are much larger than 2.457 eV/atom for Au32 fullerene, leading to the possibility of their high abundance.

  16. Survey and alignment at the ALS

    SciTech Connect

    Krebs, G.F.; Lauritzen, T.; Thur, W.

    1995-11-01

    This paper describes survey and alignment at the Lawrence Berkeley National Laboratory`s Advanced Light Source (ALS) accelerators from 1993 to 1995. The ALS is a 1.0 - 1.9 GeV electron accelerator producing extremely bright synchrotron light in the UV and soft-X-ray wavelengths. At the ALS, electrons are accelerated in a LINAC to 50 MeV, injected into a booster ring for further acceleration and finally injected into the storage ring. This is shown schematically in Figure 1. The storage ring, some 200 m in circumference, has been run with electron currents above 400 mA with lifetimes as high as 24 hours. The ALS is a third generation light source and requires for efficient storage ring operation, magnets aligned to within 150 mm of their ideal position. To accomplish this a network of monuments was established and their positions measured with respect to one another. The data was reduced using GEONET`` and STAR*NET`` software. Using the monuments as reference points, magnet positions were measured and alignment confirmed using the Kem Electronic Coordinate Determination System (ECDS``). A number of other papers dealing with survey and alignment (S&A) at the ALS have been written that may further elucidate some details of the methods and systems described in this paper.

  17. The mechanical properties of FeAl

    SciTech Connect

    Baker, I.; George, E.P.

    1996-12-31

    Only in the last few years has progress been made in obtaining reproducible mechanical properties data for FeAl. Two sets of observations are the foundation of this progress. The first is that the large vacancy concentrations that exist in FeAl at high temperature are easily retained at low temperature and that these strongly affect the low-temperature mechanical properties. The second is that RT ductility is adversely affected by water vapor. Purpose of this paper is not to present a comprehensive overview of the mechanical properties of FeAl but rather to highlight our understanding of key phenomena and to show how an understanding of the factors which control the yield strength and fracture behavior has followed the discovery of the above two effects. 87 refs, 9 figs.

  18. Boron strengthening in FeAl

    SciTech Connect

    Baker, I.; Li, X.; Xiao, H.; Klein, O.; Nelson, C.; Carleton, R.L.; George, E.P.

    1998-11-01

    The effect of boron on the strength of B2-structured FeAl is considered as a function of composition, grain size and temperature. Boron does not affect the concentrations of antisite atoms or vacancies present, with the former increasing and the latter decreasing with increasing deviation from the stoichiometric composition. When vacancies are absent, the strength increase per at. % B per unit lattice strain, {Delta}{sigma}/({Delta}c x {epsilon}) increases with increasing aluminum concentration, but when vacancies are present (>45 at. % Al), {Delta}{sigma}/({Delta}c x {epsilon}) decreases again. Boron increases grain size strengthening in FeAl. B strengthening is roughly independent of temperature up to the yield strength peak but above the point, when diffusion-assisted deformation occurs, boron strengthening increases dramatically.

  19. Primary (AL) amyloidosis in plasma cell disorders.

    PubMed

    Müller, Antonia M S; Geibel, Annette; Neumann, Hartmut P H; Kühnemund, Alexander; Schmitt-Gräff, Annette; Böhm, Joachim; Engelhardt, Monika

    2006-01-01

    Primary (AL) amyloidosis is the most common form of systemic amyloidosis. The morbidity arises from extracellular deposition of immunoglobulin light chain (LC) fibrils in major organs, such as the kidneys, heart, and bowel. Organ dysfunction contributes to a high mortality and poor prognosis, with a median survival time of 1-2 years from diagnosis. Here, we present a 46-year-old man with an exceptional clinical course of an LC multiple myeloma with generalized amyloidosis, causing renal insufficiency, congestive heart failure, and complete intestinal necrosis. We have summarized recent knowledge on AL amyloidosis, its association with monoclonal gammopathies, clinical presentations, diagnostic tools, and treatment strategies. Our comprehensive overview of this rare and often fatal disease aims to increase the awareness of AL amyloidosis. This may facilitate earlier diagnosis, and thus allow initiation of prompt and specific therapies, which are indispensable in order to improve disease prognosis. PMID:16880241

  20. Adhesion of metal carbide/nitride interfaces: Al/TiC and Al/TiN

    NASA Astrophysics Data System (ADS)

    Liu, L. M.; Wang, S. Q.; Ye, H. Q.

    2003-12-01

    We employ density functional theory to investigate and compare Al/TiC and Al/TiN interfaces by electronic structures, relaxed atomic geometries and adhesions. The results show that the preferred bonding site is the interfacial Al atoms above the ceramic's metalloid atoms for both systems. The calculated adhesion energies are quantitatively in agreement with other calculated and experimental results of Al on the carbide and nitride. A detailed comparison of the adhesion energies and relaxed structures shows weaker bonding and less relaxation in the Al/nitride case, which is correlated with the lower surface energy of the ceramic. We have thoroughly characterized the electronic structure and determined that the polar covalent Al3sp-C(N)2s bonds constitute the primary interfacial bonding interaction. The larger overlapping bonding states at the Al/TiC interface reveal the reason why it exhibits relatively larger adhesion energy. Cleavage may take place preferentially at the interface, especially for the Al/TiN, which is in agreement with experimental results.

  1. 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.

  2. Synthesis of nanostructured AlN by solid state reaction of Al and diaminomaleonitrile

    SciTech Connect

    Rounaghi, S.A.; Eshghi, H.; Kiani Rashid, A.R.; Vahdati Khaki, J.; Samadi Khoshkhoo, M.; Scudino, S.; Eckert, J.

    2013-02-15

    The solid state reaction of diaminomaleonitrile (DAMN) with aluminum via both mechanochemical and thermal treatment routes was studied by X-ray diffraction and Fourier transform infrared spectroscopy. During the milling process, the reaction starts with the deammoniation of the DAMN molecules, followed by the formation of nanostructured AlN powder as the main solid product after milling for 7 h. The reactivity of the mixed powder was also investigated during the conventional thermal treatment process using differential scanning calorimetry, derivative thermogravimetry and thermogravimetric analysis. The results reveal that DAMN starts to polymerize at 192 Degree-Sign C by the elimination of the amine groups. Furthermore, increasing the annealing temperature leads to the formation of a nitrogen-containing carbonaceous material with the structure similar to non-crystalline carbon. However, no evidence for the formation of AlN was observed in the annealed samples even at temperatures as high as the Al melting point. - Graphical abstract: AlN nanoparticles obtained after milling of Al and diaminomaleonitrile (DAMN) for 12 h. Highlights: Black-Right-Pointing-Pointer Solid state reaction of diaminomaleonitrile (DAMN) with Al was studied via mechanochemical and thermal treatment routs. Black-Right-Pointing-Pointer Nanocrystalline AlN was successfully synthesized by the mechanochemical process. Black-Right-Pointing-Pointer The C/N material was formed by polymerization of DAMN during the thermal treatment process. Black-Right-Pointing-Pointer No reaction between DAMN and Al was detected during the thermal treatment method.

  3. 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.

  4. Transport mechanisms of leakage current in Al2O3/InAlAs MOS capacitors

    NASA Astrophysics Data System (ADS)

    Jin, Chengji; Lu, Hongliang; Zhang, Yimen; Zhang, Yuming; Guan, He; Wu, Lifan; Lu, Bin; Liu, Chen

    2016-09-01

    An Al2O3 layer is inserted between the InAlAs layer and the metal gate in InAs/AlSb HEMTs to suppress the leakage current. The transport mechanisms of leakage current in Al2O3/InAlAs metal-oxide-semiconductor (MOS) capacitors at both positive and negative biases at different temperatures ranging from 10 °C to 70 °C are investigated. For positive bias, the leakage current is dominated by Schottky emission. Based on the fitted straight lines, the relative dielectric constant of Al2O3 and the barrier height between Al2O3 and InAlAs are extracted. However, for negative bias, the leakage current is dominated by Frenkel-Poole (F-P) emission and the depth of the trap energy level from the conduction band (ϕt) is extracted. Furthermore, authors explain the reason why the dominating mechanisms at positive and negative biases are different.

  5. Disordered crystal structure of 20H-AlON, Al10O3N8

    NASA Astrophysics Data System (ADS)

    Banno, Hiroki; Funahashi, Shiro; Asaka, Toru; Hirosaki, Naoto; Fukuda, Koichiro

    2015-10-01

    The disordered crystal structure of 20H-AlON (Al10O3N8) was determined by combined use of X-ray powder diffraction and transmission electron microscopy. The title compound is hexagonal with space group P63/mmc (Z=2) and the unit-cell dimensions are a=0.307082(5) nm, c=5.29447(8) nm and V=0.432376(12) nm3. The structural model showed the positional disordering of three of the six Al sites in the unit cell. The reliability indices calculated from the Rietveld method were Rwp=6.97%, S (=Rwp/Re)=1.68, Rp=5.45%, RB=5.13% and RF=4.56%. We interpreted the disordered structure of 20H-AlON as a statistical average of six different types of ordered structural configurations, which are composed of an octahedral [Al(O, N)6] layer and tetrahedral [Al(O, N)4] layers. We demonstrated the high correlations between the hexagonal unit-cell dimensions and the octahedral layer concentrations for AlON and SiAlON polytypoids.

  6. 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…

  7. 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.

  8. A Comment on Eerland et al. (2016).

    PubMed

    Hart, William

    2016-03-01

    People imagine criminal behavior in greater detail and ascribe more blame to criminals when a description of a crime is written using the imperfective verb aspect (Hart & Albarracín, 2011, Experiment 3). An initiative to reproduce these findings conducted by Eerland et al. (2016) yielded a lack of replication. Eerland et al. have suggested that the original effect was likely driven by a Type I error produced by methodological aspects of the experiment, including low sample size. Recent conceptual replications of Hart and Albarracín's effect (Sherrill, Eerland, Zwaan, & Magliano, 2015), however, might imply the effect could be contingent on sample characteristics. PMID:26993281

  9. The ALS Storage Ring RF System

    SciTech Connect

    Taylor, B.; Lo, C.C.; Baptiste, K.; Guigli, J.; Julian, J.

    1993-05-01

    The ALS Storage Ring RF System is characterized by the use of the following features: (1) High power loading of two single cell cavities. (2) The use of a tubular ceramic input window employing aperture coupling. (3) The use of waveguide filters and matchers designed for HOM absorption. (4) A comprehensive HOM monitoring system. (5) The use of waveguide water-wedge loads for the magic tee and circulator loads. The results of cavity measurements and high power tests are reported together with the performance of the system during the commissioning and operation phases of the ALS project. Plans for future window development are discussed.

  10. Quadrupole scattering in PrAl2

    NASA Astrophysics Data System (ADS)

    Sablik, M. J.; Pureur, P.; Creuzet, G.; Fert, A.; Levy, P. M.

    1983-10-01

    We derive the spontaneous anisotropy of the resistivity of the ferromagnetic compound PrAl2 from magnetoresistance measurements on a single crystal of PrAl2. We ascribe this spontaneous anisotropy of the resistivity to scattering of the conduction electrons by the thermal quadrupole disorder and we account for our experimental results by using the theoretical model previously developed by us. We find that quadrupole scattering gives a very important contribution to the total magnetic disorder (spin and quadrupole) resistivity but that only a small part of this quadrupole contribution is anisotropic.

  11. Nb3Al Development for HEP Applications

    SciTech Connect

    Sumption, M.D.; Buta, F.; Collings, E.W.; Tomsic, M.; Phillips, J.; McFadden, K.; Wu, X

    2004-06-28

    Recent developments in Nb3Al strand for HEP applications are presented and discussed. The present state of available precursor is detailed. Two routes have been shown to lead to successful construction of MF NbAl composite wires. An extrusion method has so far produced the highest filament counts and smallest filament diameters, but requires more processing steps. A direct restack and draw approach has also been demonstrated which minimizes the number of processing steps while still leading to a high performance conductor. This latter route also allows for a lower cost per billet, potentially allowing the exploration of more process parameters.

  12. 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

  13. Surface phonon polariton characteristics of In(0.04)Al(0.06)Ga(0.90)N/AlN/Al(2)O(3) heterostructure.

    PubMed

    Ng, S S; Lee, S C; Bakhori, S K Mohd; Hassan, Z; Abu Hassan, H; Yakovlev, V A; Novikova, N N; Vinogradov, E A

    2010-05-10

    Surface phonon polariton (SPP) characteristics of In(0.04)Al(0.06)Ga(0.90)N/AlN/Al(2)O(3) heterostructure are investigated by means of p-polarized infrared (IR) attenuated total reflection spectroscopy. Two absorption dips corresponding to In(0.04)Al(0.06)Ga(0.90)N SPP modes are observed. In addition, two prominent dips and one relatively weak and broad dip corresponding to the Al(2)O(3) SPP mode, In(0.04)Al(0.06)Ga(0.90)N/Al(2)O(3) interface mode, and Al(2)O(3) bulk polariton mode, respectively, are clearly seen. No surface mode feature originating from the AlN layer is observed because it is too thin. Overall, the observations are in good agreement with the theoretical predictions. PMID:20588890

  14. 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.

  15. 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.

  16. Al/sub 2/O/sub 3/ adherence on CoCrAl alloys

    SciTech Connect

    Kingsley, L.M.

    1980-04-01

    Adherence of protective oxides on NiCrAl and CoCrAl superalloys has been promoted by a dispersion of a highly oxygen reactive element or its oxide being produced within the protection system. Two aspects of this subject are investigated here: the use of Al/sub 2/O/sub 3/ as both the dispersion and protective oxide; and the production of an HfO/sub 2/ dispersion while simultaneously aluminizing the alloy. It was found that an Al/sub 2/O/sub 3/ dispersion will act to promote the adherence of an external scale of Al/sub 2/O/sub 3/ to a degree comparable to previously tested dispersions and an HfO/sub 2/ dispersion comparable to that produced by a Rhines pack treatment is produced during aluminization.

  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. In situ microscopy of rapidly heated nano-Al and nano-Al/WO3 thermites

    NASA Astrophysics Data System (ADS)

    Sullivan, Kyle T.; Chiou, Wen-An; Fiore, Richard; Zachariah, Michael R.

    2010-09-01

    The initiation and reaction mechanism of nano-Al and nano-Al thermites in rapid heating environments is investigated in this work. A semiconductor-based grid/stage was used, capable of in situ heating of a sample from room temperature to 1473 K, and at a rate of 106 K/s, inside an electron microscope. Nano-Al was rapidly heated in a transmission electron microscope, and before and after images indicate that the aluminum migrates through the shell, consistent with a diffusion-based mechanism. A nano-Al/WO3 composite was then heated in a scanning electron microscope. The results indicate that a reactive sintering mechanism is occurring for the nano-Al/WO3 thermite, as the products are found to be in surface contact and significantly deformed after the heating pulse.

  19. Preparation, structure and mechanical properties of RuAl and (Ru,Ni)Al alloys

    SciTech Connect

    Sabariz, A.L.R.; Taylor, G.

    1997-12-31

    The intermetallic compound, RuAl with B2 CsCl type structure, has been shown to possess room-temperature toughness and plasticity. NiAl also forms a B2 compound and it is claimed that a pseudo-binary compound, (Ru,Ni)Al, may be formed because the difference in lattice parameter between the two binary phases is slight. In this work a study has been made of the mechanical properties of some polycrystalline compounds, across the RuAl-(Ru,Ni)Al pseudo-binary, prepared from high-purity elemental powders. Compressive yield stresses were measured between room-temperature and 900 C, and the mechanisms of plastic flow are discussed in relation to the dislocation structures observed by TEM. Hot-microhardness tests were made to provide an indication of the effect of solid-solution hardening.

  20. 1300 K compressive properties of a reaction milled NiAl-AlN composites

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Arzt, Eduard; Luton, Michael J.

    1990-01-01

    When B2 crystal-structure nickel aluminide is subjected to high-intensity mechanical ball milling in a liquid nitrogen bath, or 'cryomilling', an NiAl composite is obtained which contains about 10 vol pct AlN particles. This composition arises from the incorporation of N during cryomilling; during subsequent thermomechanical processing, the N reacts with Al. While compressive testing of extruded or isostatically pressed specimens at 1300 K indicated that strength at relatively fast strain rates is slightly dependent on consolidation method, slower strain rates indicate no clear dependency on densification technique: four different consolidation methods were found to yield similar creep strengths. The creep properties of NiAl-AlN are similar to those of the single-crystal Ni-base superalloy NASAIR 100.

  1. Temperature dependence of the activity of Al in dilute Ni(Al) solid solutions

    SciTech Connect

    Jiang Yong; Smith, J. R.; Evans, A. G.

    2006-12-01

    Activities of dilute Al solid solutions in Ni are determined from a first-principles approach. Both thermal lattice vibration and electronic contributions to free energies are considered and compared. Vibrational contributions tend to dominate the temperature dependencies of the free energies, though electron thermal effects are significant. Calculations show opposing temperature trends for the formation enthalpies and entropies, leading to a partial cancellation of their role in the overall energetics. Nevertheless, their remaining temperature effects are strong. Over the temperature range, 400 KAl activity coefficient varies by 15 orders of magnitude, due to the relative strength of Al-Ni and Al-Al bonds. The Ni activity coefficient only varies less than 4% over the same range. Calculational results compare well with available experimental data. The thermodynamic principles elucidated from the calculations are used to provide a fundamental interpretation.

  2. 26Al+p elastic and inelastic scattering reactions and galactic abundances of 26Al

    NASA Astrophysics Data System (ADS)

    Pittman, S. T.; Bardayan, D. W.; Chae, K. Y.; Chipps, K. A.; Jones, K. L.; Kozub, R. L.; Matei, C.; Matos, M.; Moazen, B. H.; Nesaraja, C. D.; O'Malley, P. D.; Pain, S. D.; Parker, P. D.; Peters, W. A.; Shriner, J. F., Jr.; Smith, M. S.

    2012-06-01

    Galactic 26Al is the first radioactive nucleus to be positively identified by γ-ray astronomy with detection of the 1.809 MeV γ ray associated with its decay. This nucleus is destroyed in astrophysical environments in the 26Al(p,γ)27Si and inelastic 26Al+p scattering reactions where properties of 27Si levels determine reaction rates. To investigate these properties, elastic and inelastic 26Al+p scattering reactions were measured between Ec.m. = 0.5-1.5 MeV at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL). A candidate for a new resonance in the 26Al(p,γ)27Si reaction was identified. Upper limits were also set on the strengths of postulated resonances and on the cross section of the inelastic reaction, but there is little effect on current reaction rate calculations.

  3. Effect of stress on the Al composition evolution in AlGaN grown using metal organic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    He, Chenguang; Qin, Zhixin; Xu, Fujun; Zhang, Lisheng; Wang, Jiaming; Hou, Mengjun; Zhang, Shan; Wang, Xinqiang; Ge, Weikun; Shen, Bo

    2016-05-01

    Two series of AlGaN samples with different stresses were designed to investigate the effect of stress on the Al composition. X-ray diffraction reciprocal space mapping (XRD RSM) demonstrated that the AlGaN epilayers with different stresses have large Al composition differences despite the same growth conditions. The largest Al composition difference reached up to 21.3%, which was also confirmed using secondary ion mass spectroscopy (SIMS). This result is attributed to a large stress discrepancy in the AlGaN epilayers. Finally, the dependences of the solid-phase Al composition on the gas-phase Al composition under different stresses were systematically analyzed.

  4. Equilibrium point defects in intermetallics with the [ital B]2 structure: NiAl and FeAl

    SciTech Connect

    Fu, C.L.; Ye, Y.; Yoo, M.H. ); Ho, K.M. )

    1993-09-01

    Equilibrium point defects and their relation to the contrasting mechanical behavior of NiAl and FeAl are investigated. For NiAl, the defect structure is dominated by two types of defects---monovacancies on the Ni sites and substitutional antisite defects on the Al sites. The defect structure of FeAl differs from that of NiAl in the occurrence of antisite defects at the transition-metal sites for Al-rich alloys and the tendency for vacancy clustering. The strong ordering (and brittleness) of NiAl is attributed mainly to the difference in atomic size between constituent atoms.

  5. Wear characteristics of Al-AlN composites produced in-situ by nitrogenation

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Jena, S. K.; Patnaik, S. C.; Swain, P. K.; Majhi, J.

    2015-02-01

    In the present scenario most of the parts used in automobile and aerospace industries are made of composites. Aluminium metal has a very high strength to weight ratio. Al-AlN metal matrix composites have excellent mechanical properties like good wear resistance, high hardness and high strength to weight ratio which are obtained from low density of aluminium and high hardness and wear resistance of AlN. Therefore, use of Al-AlN MMC leads to advantages in automobile industries as it reduces fuel consumption and gives better structural strength. The composites can be produced ex-situ by introducing AlN as reinforcement into the metal matrix and in- situ by nitrogenation process. In the present process Al-AlN composites were fabricated by treating molten aluminium with a mixture of CaO and NH4Cl and held at temperature range at 750-930°C and then cast into a metal mould. Addition of CaO to NH4Cl is found to have a more pronounced effect as a nitrogenation agent in comparison with NH4Cl in the molten aluminium in the temperature range of 700- 1000°C. Castings of aluminium and Al-AlN composites were prepared by mixing different ratios of aluminium and NH4Cl, at different casting temperatures and holding time. Wear resistance and hardness of the samples were determined, and microstructure studies were carried out. The composite formed using higher amount of NH4Cl had higher hardness and wear resistance.

  6. Microstructure of Ni-Al powder and Ni-Al composite coatings prepared by twin-wire arc spraying

    NASA Astrophysics Data System (ADS)

    Wang, Ji-xiao; Wang, Gui-xian; Liu, Jing-shun; Zhang, Lun-yong; Wang, Wei; Li, Ze; Wang, Qi-xiang; Sun, Jian-fei

    2016-07-01

    Ni-Al powder and Ni-Al composite coatings were fabricated by twin-wire arc spraying (TWAS). The microstructures of Ni-5wt%Al powder and Ni-20wt%Al powder were characterized by scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that the obtained particle size ranged from 5 to 50 μm. The morphology of the Ni-Al powder showed that molten particles were composed of Ni solid solution, NiAl, Ni3Al, Al2O3, and NiO. The Ni-Al phase and a small amount of Al2O3 particles changed the composition of the coating. The microstructures of the twin-wire-arc-sprayed Ni-Al composite coatings were characterized by SEM, EDS, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results showed that the main phase of the Ni-5wt%Al coating consisted of Ni solid solution and NiAl in addition to a small amount of Al2O3. The main phase of the Ni-20wt%Al coating mainly consisted of Ni solid solution, NiAl, and Ni3Al in addition to a small amount of Al and Al2O3, and NiAl and Ni3Al intermetallic compounds effectively further improved the final wear property of the coatings. TEM analysis indicated that fine spherical NiAl3 precipitates and a Ni-Al-O amorphous phase formed in the matrix of the Ni solid solution in the original state.

  7. Thermodynamics and Kinetics of the Formation of Al2O3/ MgAl2O4/MgO in Al-Silica Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Sreekumar, V. M.; Ravi, K. R.; Pillai, R. M.; Pai, B. C.; Chakraborty, M.

    2008-04-01

    The formation of Al2O3, MgAl2O4, and MgO has been widely studied in different Al base metal matrix composites, but the studies on thermodynamic aspects of the Al2O3/ MgAl2O4/MgO phase equilibria have been limited to few systems such as Al/Al2O3 and Al/SiC. The present study analyzes the Al2O3/MgAl2O4 and MgAl2O4/MgO equilibria with respect to the temperature and the Mg content in Al/SiO2 system using an extended Miedema model. There is a linear and parabolic variation in Mg with respect to the temperature for MgAl2O4/MgO and Al2O3/MgAl2O4 equilibria, respectively, and the influence of Si and Cu in the two equilibria is not appreciable. The experimental verification has been limited to MgAl2O4/MgO equilibria due to the high Mg content (≥0.5 wt pct) required for composite processing. The study has been carried out on two varieties of Al/SiO2 composites, i.e., Al/Silica gel and Al/Micro silica processed by liquid metallurgy route (stir casting route). MgO is found to be more stable compared to MgAl2O4 at Mg levels ≥5 and 1 wt pct in Al/Silica gel and Al/Micro silica composites, respectively, at 1073 K. MgO is also found to be more stable at lower Mg content (3 wt pct) in Al/Silica gel composite with decreasing particle size of silica gel from 180 micron to submicron and nanolevels. The MgO to MgAl2O4 transformation has taken place through a series of transition phases influenced by the different thermodynamic and kinetic parameters such as holding temperature, Mg concentration in the alloy, holding time, and silica particle size.

  8. Bierman {ital et al.}Reply:

    SciTech Connect

    Bierman, J.D.; Chan, P.; Liang, J.F.; Kelly, M.P.; Sonzogni, A.A.; Vandenbosch, R.

    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}

  9. 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.

  10. Electron impact exctation of Al X

    NASA Astrophysics Data System (ADS)

    Aggarwal, Kanti; Keenan, Francis

    2013-05-01

    Emission lines of Al ions, including Al X, are important for the modeling and diagnostics of lasing, fusion and astrophysical plasmas, for which atomic data are required for a variety of parameters, such as energy levels, radiative rates (A- values), and excitation rates or equivalently the effective collision strengths (Υ), which are obtained from the electron impact collision strengths (Ω). Experimentally, energy levels are available for Al X on the NIST website, but there is paucity for accurate collisional atomic data. Therefore, here we report a complete set of results (namely energy levels, radiative rates, and effective collision strengths) for all transitions among the lowest 98 levels of Al X. These levels belong to the (1s2) 2s2, 2s2p, 2p2, 2s3 l, 2p3 l, 2s4 l, and 2p4 l configurations. Finally, we also report the A- values for four types of transitions, namely electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2), because these are also required for plasma modeling. For our calculations of wavefunctions, we have adopted the fully relativistic GRASP code, and for the calculations of Ω, the Dirac atomic R-matrix code (DARC) of PH Norrington and IP Grant. Additionally, parallel ca

  11. 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…

  12. 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.

  13. 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

  14. 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.

  15. 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…

  16. Al-Ghazali on Moral Education

    ERIC Educational Resources Information Center

    Alavi, Hamid Reza

    2007-01-01

    Al-Ghazali (1058-1111 CE) is probably the most influential scholar, philosopher, theologian, legal expert, religious reformer and mystic in the history of Islam. Although he wrote extensively about education, and particularly about moral education, this writing is scattered through a number of different works and has received less scholarly…

  17. 75 FR 26814 - Alabama Disaster #AL-00031

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00031 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  18. 76 FR 29810 - Alabama Disaster #AL-00037

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-23

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00037 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  19. 75 FR 474 - Alabama Disaster #AL-00026

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00026 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  20. 78 FR 4967 - Alabama Disaster #AL-00046

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-23

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00046 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of ALABAMA dated...

  1. 76 FR 27141 - Alabama Disaster # AL-00036

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00036 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Alabama...

  2. 78 FR 22361 - Alabama Disaster #AL-00049

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-15

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00049 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Alabama dated...

  3. 75 FR 26813 - Alabama Disaster #AL-00029

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00029 AGENCY: Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Alabama...

  4. 77 FR 60003 - Alabama Disaster #AL-00044

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-01

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00044 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  5. 77 FR 7227 - Alabama Disaster #AL-00040

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00040 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Alabama...

  6. 75 FR 1420 - Alabama Disaster # AL-00025

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-11

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00025 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Alabama dated...

  7. 76 FR 62481 - Incapital LLC, et al.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-07

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Incapital LLC, et al.; Notice of Application September 30, 2011. AGENCY: Securities and Exchange Commission (``Commission''). ACTION: Notice of application for an order under section 12(d)(1)(J) of...

  8. 78 FR 26100 - Alabama Disaster #AL-00050

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-03

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00050 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Alabama dated...

  9. SPI measurements of Galactic 26Al

    NASA Astrophysics Data System (ADS)

    Diehl, R.; Knödlseder, J.; Lichti, G. G.; Kretschmer, K.; Schanne, S.; Schönfelder, V.; Strong, A. W.; von Kienlin, A.; Weidenspointner, G.; Winkler, C.; Wunderer, C.

    2003-11-01

    The precision measurement of the 1809 keV gamma-ray line from Galactic 26Al is one of the goals of the SPI spectrometer on INTEGRAL with its Ge detector camera. We aim for determination of the detailed shape of this gamma-ray line, and its variation for different source regions along the plane of the Galaxy. Data from the first part of the core program observations of the first mission year have been inspected. A clear detection of the 26Al line at =~ 5-7 sigma significance demonstrates that SPI will deepen 26Al studies. The line intensity is consistent with expectations from previous experiments, and the line appears narrower than the 5.4 keV FWHM reported by GRIS, more consistent with RHESSI's recent value. Only preliminary statements can be made at this time, however, due to the multi-component background underlying the signal at =~ 40 times higher intensity than the signal from Galactic 26Al.

  10. Al/Cl2 molten salt battery

    NASA Technical Reports Server (NTRS)

    Giner, J.

    1972-01-01

    Molten salt battery has been developed with theoretical energy density of 5.2 j/kg (650 W-h/lb). Battery, which operates at 150 C, can be used in primary mode or as rechargeable battery. Battery has aluminum anode and chlorine cathode. Electrolyte is mixture of AlCl3, NaCl, and some alkali metal halide such as KCl.

  11. 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…

  12. 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 the 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.

  13. 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.

  14. Thermal mixing of Al-Fe multilayers

    NASA Astrophysics Data System (ADS)

    Meyer, M.; Mendoza Zélis, L.; Sánchez, F. H.; Traverse, A.

    1994-12-01

    Al-Fe multilayers have been mixed by thermal treatment and their evolution followed by conversion electron Mössbauer spectroscopy. The initial and final states have been characterized by Rutherford backscattering spectrometry. The results are compared with those previously obtained in the ion beam mixing of similar systems.

  15. 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.

  16. Calculation of the structure of the Al(331) stepped surface

    SciTech Connect

    Nelson, J.S.; Feibelman, P.J. )

    1992-04-06

    Car-Parinello-like calculations have been used to compute the relaxation of the Al(331) surface, with results that are in remarkable agreement with the low-energy electron-diffraction analysis of Adams and So( )renson. Rapid screening of the steps on Al(331) is illustrated by comparing its charge density and relaxations to those of Al(110) and Al(111).

  17. 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 have been 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. It was postulated that the voids resulted from an excess number of oxygen vacancies near the oxide-metal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidations 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 relationships between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.

  18. Electrical defects in AlGaN and InAlN

    NASA Astrophysics Data System (ADS)

    Johnstone, D.; Leach, Jacob H.; Kovalskii, Vladimir A.; Fan, Qian; Xie, Jingqiao; Morkoç, Hadis

    2009-02-01

    Compound semiconductors based on GaN have multiple functional applications. Useful compositions include GaN, and ternary and quaternary compositions of (AlGaIn)N. Defects arising from lattice mismatch, point defects, or impurities may act as electrical trapping centers and degrade device efficiency. Current-voltage, capacitance-voltage, thermal admittance spectroscopy (TAS), and deep level transient spectroscopy (DLTS) measurements are applied to characterize the defects in Al0.40Ga0.80N and In0.18Al0.82N in this report. Broad peaks with a shoulder at high temperature dominate the DLTS spectra in each of the materials. An acceptor trap associated with a dislocation appears at 340 K in AlGaN. The defect has an energy of 0.2 eV and capture cross section of 10-21 cm2. A second trap at 0.35 eV, 10-14 cm2 appears in the TAS measurements in addition to the trap at 0.2 eV. Defects in InAlN are dominated by a peak near 150 K. Two traps appear in the TAS measurements. Both traps in the InAlN are acceptors, based on a lack of field dependent emission rates using double pulse DLTS (DDLTS). The two energy levels in InAlN appear to be coupled, with only one state occupied at a time.

  19. 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.

  20. Thermoelectric Powers of Cells With NaF-AlF3-Al2O3 Melts

    NASA Astrophysics Data System (ADS)

    Flem, Belinda E.; Xu, Qian; Kjelstrup, Signe; Sterten, Åsmund

    2001-07-01

    A thermodynamic description of the Peltier heat at the aluminum and the oxygen electrode in the system NaF-AlF3-Al2O3 is given. The thermoelectric power in melts with molar ratios n NaF/n AlF3 from 3.0 to 1.0, saturated with alumina are measured. Seebeck coefficients for molten fluoride electrolytes saturated with alumina, electrolytes that are relevant for aluminum electrowinning electrolysis cells, are reported. The results allow determinations of Peltier heats of aluminum, oxygen and carbon electrodes in NaF-AlF3 electrolytes saturated with alumina. For molar ratios of n NaF/n AlF3 between 2.6 and 1.2, there is a Peltier heating of the aluminum cathode. This heating is in the same order of magnitude as the electrolyte Joule heat, when the current density is 0.7 A cm-2. For molar ratio n NaF/n AlF3 equal to 1.0 the Peltier effect at the aluminum electrode approaches zero. From theoretical considerations we expect a drop also for molar ratio 3.0. For the anode we report a Peltier cooling that is larger than the heat produced by the anodic overvoltage, in melts with NaF/AlF3 molar ratio between 2.6 and 1.2 saturated with alumina.

  1. High noise suppression using magnetically isotropic (CoFe-AlN)/(AlN) multilayer films

    NASA Astrophysics Data System (ADS)

    Kijima, Hanae; Ohnuma, Shigehiro; Masumoto, Hiroshi; Shimada, Yutaka; Endo, Yasushi; Yamaguchi, Masahiro

    2015-05-01

    Magnetically isotropic (CoFe-AlN)n/(AlN)n+1 multilayer films, in which the number of CoFe-AlN magnetic layers n ranged from 1 to 27, were prepared by radio frequency sputtering to achieve noise suppression at gigahertz frequencies. The soft CoFe-AlN magnetic layers consisted of nanometer-sized CoFe ferromagnetic grains embedded in an insulating AlN amorphous matrix, while the insulating AlN layers comprised AlN columnar crystals. All films showed a similar frequency dependence of permeability and ferromagnetic resonance of 1.7 GHz. Noise suppression was evaluated using a microstrip line as a noise source by determining the in-line conductive loss and the near-field intensity picked up by magnetic field detective probes. High noise suppression effects were observed in every direction in the film plane. Maximum noise suppression values amounted to 60% for the in-line conductive loss and -20 dB for the magnetic near-field intensity at around 1.7 GHz in the 27-layer film. These high-frequency noise suppression levels may be attributed to eddy current losses and ferromagnetic resonance.

  2. A 25-year replication of Katz et al.'s (1988) metaphor norms.

    PubMed

    Campbell, Spencer J; Raney, Gary E

    2016-03-01

    Research in metaphor processing has made extensive use of the normed metaphor database created by Katz, Paivio, Marschark, & Clark (Metaphor and Symbolic Activity, 3, 191-214, 1988). Because of the plasticity of figurative language, we conducted a renorming of selected metaphors from the database on a new student population. Correlations between Katz et al.'s and the present data showed that the pattern of responses has remained highly consistent across time and populations. The consistency of the normative ratings allows us to be confident in future research that will use the Katz et al. collection. PMID:25772671

  3. Ferromagnetic ordering in NpAl2: Magnetic susceptibility and 27Al nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Martel, L.; Griveau, J.-C.; Eloirdi, R.; Selfslag, C.; Colineau, E.; Caciuffo, R.

    2015-08-01

    We report on the magnetic properties of the neptunium based ferromagnetic compound NpAl2. We used magnetization measurements and 27Al NMR spectroscopy to access magnetic features related to the paramagnetic and ordered states (TC=56 K). While very precise DC SQUID magnetization measurements confirm ferromagnetic ordering, they show a relatively small hysteresis loop at 5 K reduced with a coercive field HCo~3000 Oe. The variable offset cumulative spectra (VOCS) acquired in the paramagnetic state show a high sensitivity of the 27Al nuclei spectral parameters (Knight shifts and line broadening) to the ferromagnetic ordering, even at room temperature.

  4. 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.

  5. Low cycle fatigue of FeAl(42 at. % Al) at room temperature

    SciTech Connect

    Hanes, D.B.; Gibala, R.

    1997-12-31

    The monotonic mechanical behavior in tension and compression of FeAl has been well documented. However, very little work has been done on the cyclic deformation behavior of this material. In this work, the behavior of FeAl (42 at. % Al) under low cycle fatigue was studied, including the effects of test environments and surface coatings. It was found that the fatigue life of this alloy is limited by environmental embrittlement. This embrittlement process can be equally well prevented by deformation in an oxygen environment or by coating the alloy with a protective film. The type of film applied appears to have little effect. Similar results were seen in monotonic testing.

  6. Al-based metal matrix composites reinforced with nanocrystalline Al-Ti-Ni particles

    NASA Astrophysics Data System (ADS)

    Scudino, S.; Ali, F.; Surreddi, K. B.; Prashanth, K. G.; Sakaliyska, M.; Eckert, J.

    2010-07-01

    Al-based metal matrix composites containing different volume fractions of nanocrystalline Al70Ti20Ni10 reinforcing particles have been produced by powder metallurgy and the effect of the volume fraction of reinforcement on the mechanical properties of the composites has been studied. Room temperature compression tests reveal a considerable improvement of the mechanical properties as compared to pure Aluminum. The compressive strength increases from 155 MPa for pure Al to about 200 and 240 MPa for the samples with 20 and 40 vol.% of reinforcement, respectively, while retaining appreciable plastic deformation with a fracture strain ranging between 43 and 28 %.

  7. Adherent Al2O3 scales formed on undoped NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    1987-01-01

    Changes in the spalling behavior of Al2O3 scales formed on an undoped NiCrAl alloy are described. Two samples of Ni-15Cr-13Al (wt pct), one a control and the other sanded, were subjected to 25 oxidation cycles. It is observed that adherent scales formed on the sanded sample; however, the control sample had speckled, spalled scales. The data reveal that the adherent scales are caused by repeated removal of surface layers after each oxidation cycle. It is determined that interfacial segregation of sulfur influences spallation and sulfur removal increases bonding. The effect of moisture on scale adhesions is investigated.

  8. Atomic layer epitaxy of AlAs and AlGaAs

    NASA Astrophysics Data System (ADS)

    Meguro, T.; Iwai, S.; Aoyagi, Y.; Ozaki, K.; Yamamoto, Y.; Suzuki, T.; Okano, Y.; Hirata, A.

    1990-01-01

    Atomic layer epitaxy (ALE) of AlAs and AlGaAs with metalorganic vapor-phase epitaxy (MOVPE) under Ar-ion laser irradiation has been successfully realized in a triethylaluminum (TEA)/AsH 3 system for the first time. Comparison with the growth characteristics of MOVPE with alternative feeding modes of TMA/AsH 3 and TEA/AsH 3 is discussed. Application to laser-ALE of AlGaAs using a triethylgallium (TEG)/TEA/AsH 3 system is also discussed.

  9. 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.

  10. Density of Low-Temperature KF-AlF3 Aluminum Baths with Al2O3 and AlPO4 Additives

    NASA Astrophysics Data System (ADS)

    Vasková, Zuzana; Kontrík, Martin; Mlynáriková, Jarmila; Boča, Miroslav

    2015-02-01

    The density of the KF-AlF3 melts of various KF and AlF3 ratio with Al2O3 and AlPO4 addition has been measured using the Archimedean method. On the basis of the obtained density data the molar volumes of the melts were calculated. These molar volumes decrease with concentration of Al2O3 or AlPO4. In the system containing AlPO4, the relation between cryolite ratios (CRs) vs slopes of molar volume trend lines was identified with excellent correlation factor of R 2 = 0.9844, while in the system containing Al2O3 a discontinuity at CR = 2.5 can be observed.

  11. [Assay of three kinds of aluminum fractions (Al(a), Al(b) and Al(c)) in polynuclear aluminum solutions by Al-Ferron timed spectrophotometry and demarcation of their time limits].

    PubMed

    Wang, Chen-yi; Zhang, Cai-hua; Bi, Shu-ping; Zhang, Zhen-chao; Yang, Wei-hua

    2005-02-01

    Al-Ferron timed spectrophotometry assay is a basic method in the study on the formation of polynuclear hydroxyl aluminum species and their transformation laws in aqueous systems. In actual working process, this methodology has some dogmatism and arbitrariness in the time limits demarcation of the three kinds of aluminum fractions (Al(a), Al(b) and Al(c)) in polynuclear aluminum solutions, which makes this kind of classification rougher, and the experimental results non-reproducible. The reason for this difference is that the specific species within Al(a), Al(b) and Al(c) have different reaction mechanism and dynamics, and that specific species of Al(b) having different OH/Al ratios have different reaction rates with ferron. In this paper, the ExpAssoc distribution was applied to quantitatively fit the Al-Ferron reaction dynamics curve, and the extrapolation method was used to survey the 1 min measured value [Al(a)] of monomeric Al, which is hard to obtain in manual manipulation. The time demarcation between Al(b) and Al(c) should reach the point of the experimental data curve up to horizontal platform. The microwave-radiated technology was used to fast assay the total aluminum concentration [Al(T)]. With these methods, the contents of monomeric Al(a), polynuclear Al(b) and gel Al(c) can be conveniently and quantitatively measured. It offers a novel method for surmounting the arbitrariness in the measurement of the three kinds of aluminum fractions and the repetitive calculation of Al(a) and Al(b). PMID:15852869

  12. Characterization of Al30 in commercial poly-aluminum chlorohydrate by solid-state (27)Al NMR spectroscopy.

    PubMed

    Phillips, Brian L; Vaughn, John S; Smart, Scott; Pan, Long

    2016-08-15

    Investigation of commercially produced hydrolysis salts of aluminum by solid-state (27)Al NMR spectroscopy and size-exclusion chromatography (SEC) reveals well-defined and distinct Al environments that can be related to physicochemical properties. (27)Al MAS and MQ-MAS NMR spectroscopic data show that the local structure of the solids is dominated by moieties that closely resemble the Al30 polyoxocation (Al30O8(OH)56(H2O)26(18+)), accounting for 72-85% of the total Al. These Al30-like clusters elute as several size fractions by SEC. Comparison of the SEC and NMR results indicates that the Al30-like clusters includes intact isolated clusters, moieties of larger polymers or aggregates, and possibly fragments resembling δ-Al13 Keggin clusters. The coagulation efficacy of the solids appears to correlate best with the abundance of intact Al30-like clusters and of smaller species available to promote condensation reactions. PMID:27232539

  13. Synthesis and characterization of Al-Zn/Al2O3 nano-powder composites.

    PubMed

    Durai, T G; Das, Karabi; Das, Siddhartha

    2007-06-01

    Composites consisting of Al-Zn/Al2O3 have been synthesized using high energy mechanical milling. High energy ball milling increases the sintering rate of the composite powder due to increased diffusion rate. Owing to the finer microstructure, the hardness of the sintered composite produced by using the mechanically milled nanocomposite powder is significantly higher than that of the sintered composite produced by using the as-mixed powder. The mean crystallite size of the matrix has been determined to be 27 nm by Scherrer equation using X-ray diffraction data. The powders have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and differential thermal analysis (DTA). The effect of high-energy ball milling and subsequent annealing on a mixture of Al and ZnO has also been investigated. DTA result show that the reaction temperature of Al-ZnO decreases with the increase in the ball milling time. PMID:17654976

  14. 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.

  15. Nonstatistical fluctuations for deep inelastic processes in {sup 27}Al+{sup 27}Al collisions

    SciTech Connect

    Berceanu, I.; Duma, M.; Moisa, D.; Petrovici, M.; Pop, A.; Simion, V.; Zoppo, A. Del; D'Erasmo, G.; Imme, G.; Lanzano, G.; Pagano, A.; Pantaleo, A.; Raciti, G.

    2006-08-15

    The excitation functions (EFs) for different fragments produced in the {sup 27}Al+{sup 27}Al dissipative collisions have been measured in steps of 250 keV in the incident energy range 122-132 MeV. Deep inelastic processes have been selected by integrating events on a total kinetic energy loss window of 12 MeV between 20 and 32 MeV. Large fluctuations are observed in all the studied EFs. Large-channel cross-correlation coefficients confirm the nonstatistical origin of these fluctuations. The energy autocorrelation function (EAF) shows damped oscillation structure as expected when a dinuclear system with a lifetime [{tau}=(5.1{+-}2.1){center_dot}10{sup -21}s], similar with its revolution period (T=4.9{center_dot}10{sup -21}sec), is formed. From the periodicity of the EAF oscillations, information on the deformation of the {sup 27}Al+{sup 27}Al dinucleus is inferred.

  16. Formation of AlN in laser ablated plasma of Al in nitrogen ambient

    NASA Astrophysics Data System (ADS)

    Thareja, Raj K.; Sharma, A. K.

    2005-05-01

    We report on spectroscopic investigations of interaction of an expanding laser ablated plume of aluminum and graphite with nitrogen gas and the formation of AlN and CN. AlN and CN bands are formed by reactive process of ablated aluminum and graphite in ambient nitrogen pressures of 70 and 0.1 Torr and laser fluence of 500 and 12 Jcm-2 respectively. Images of the expanding plasma plume were captured using ICCD to understand the role of vapor and shock temperature in the formation of AlN. Instability observed in laser ablated plume at later times attributed to Rayleigh-Taylor instability could be the cause for weak AlN band observed in the emission spectrum.

  17. Fabrication and properties of functionally graded NiAl/Al2O3 composites

    NASA Technical Reports Server (NTRS)

    Miller, D. P.; Lannutti, J. J.; Noebe, R. D.

    1993-01-01

    A modified sedimentation process was used in the production of a functionally gradient material (FGM), NiAl/Al2O3. A simple finite element model was used to guide our design and fabrication efforts by estimating residual stress states as a function of composite structure. This approach could lead to tailored designs that enhance or avoid specific residual stress states. Thermal cycling tests were factored into the model to predict time dependent or steady-state internal temperature and stress profiles. Four-point bend tests were conducted to establish the mechanical load-displacement behavior of a single interlayer FGM at room temperature, 800 and 1000 K. Room temperature bend strength of the FGM was 3-4 times that of the base NiAl. At elevated temperatures, composite fracture occurred in a gradual, noncatastrophic mode involving NiAl retardation of a succession of cracks originating in the alumina face.

  18. '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.

  19. Al Knight-shift measurement in the superconducting state of UNi 2Al 3

    NASA Astrophysics Data System (ADS)

    Ishida, K.; Tou, H.; Tateiwa, N.; Kitaoka, Y.; Sato, K. N.; Aso, N.; Geibel, C.; Steglich, F.

    2003-05-01

    We report 27Al Knight-shift (27K) measurement on a single-crystal UNi2Al3 that reveals a coexistence of superconductivity and a spin-density-wave (SDW) type of magnetic ordering (TSDW=4.5 K). The spin part of 27K, 27Ks does not change down to 50 mK across the superconducting (SC) transition temperature Tc∼0.9 K. In contrast with the isostructural compound UPd2Al3 (Tc∼2 K), which was identified to be a spin-singlet d-wave superconductor, the behavior of 27K strongly supports that UNi2Al3 belongs to a class of spin-triplet SC pairing state superconductor.

  20. Local stress-induced effects on AlGaAs/AlOx oxidation front shape

    SciTech Connect

    Chouchane, F.; Almuneau, G. Arnoult, A.; Lacoste, G.; Fontaine, C.; Cherkashin, N.

    2014-07-28

    The lateral oxidation of thick AlGaAs layers (>500 nm) is studied. An uncommon shape of the oxide tip is evidenced and attributed to the embedded stress distribution, inherent to the oxidation reaction. Experimental and numerical studies of the internal strain in oxidized Al{sub x}Ga{sub 1−x}As/GaAs structures were carried out by dark-field electron holography and finite element methods. A mapping of the strain distribution around the AlGaAs/oxide interface demonstrates the main role of internal stress on the shaping of the oxide front. These results demonstrate the high relevance of strain in oxide-confined III-V devices, in particular, with over-500-nm thick AlOx confinement layers.

  1. Interdiffusion in the Mg-Al system and Intrinsic Diffusion in (Al3Mg2) Phase

    SciTech Connect

    Brennan, Sarah; Bermudez, Katrina; Kulkarni, Nagraj S; Sohn, Yong Ho

    2011-01-01

    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 -Al12Mg17 and -Al3Mg2, but not -phase. Concentration profiles were determined using X-ray energy dispersive spectroscopy (XEDS). The growth constants and activation energies were determined for each intermetallic phase.

  2. 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.

  3. Alkali metal adsorption on Al(111)

    NASA Astrophysics Data System (ADS)

    Andersen, J. N.; Lundgren, E.; Nyholm, R.; Qvarford, M.

    1993-06-01

    The submonolayer adsorption of Na, K, Rb, and Cs on the Al(111) surface at 100 K and at room temperature is investigated by high resolution core level spectroscopy and low energy electron diffraction. It is found that the first alkali atoms on the surface adsorb at surface defects. At higher coverages, up to approximately one third of the maximum submonolayer coverage, alkali atoms adsorbed at defects coexist with a dispersed phase. At higher coverages island formation is found to occur for the majority of the systems. It is argued that all of the ordered structures formed at room temperature involve a disruption of the Al(111) surface in contrast to the situation at 100 K where the alkali atoms adsorb as adatoms.

  4. Forging of FeAl intermetallic compounds

    SciTech Connect

    Flores, O.; Juarez, J.; Campillo, B.; Martinez, L.; Schneibel, J.H.

    1994-09-01

    Much activity has been concentrated on the development of intermetallic compounds with the aim of improving tensile ductility, fracture toughness and high notch sensitivity in order to develop an attractive combination of properties for high and low temperature applications. This paper reports experience in processing and forging of FeAl intermetallic of B2 type. During the experiments two different temperatures were employed, and the specimens were forged after annealing in air, 10{sup {minus}2} torr vacuum and argon. From the results it was learned that annealing FeAl in argon atmosphere prior to forging resulted in better deformation behavior than for the other two environments. For the higher forging temperature used in the experiments (700C), the as-cast microstructure becomes partially recrystallized.

  5. Observable Proxies For 26 Al Enhancement

    SciTech Connect

    Fryer, Christopher L; Young, Patrick A; Ellinger, Carola I; Arnett, William D

    2008-01-01

    We consider the cospatial production of elements in supernova explosions to find observationally detectable proxies for enhancement of {sup 26}Al in supernova ejecta and stellar systems. Using four progenitors we explore a range of 1D explosions at different energies and an asymmetric 3D explosion. We find that the most reliable indicator of the presence of {sup 26}Al in unmixed ejecta is a very low S/Si ratio ({approx} 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 multi wavelength observations, but the small absolute abundance of material injected into a proto-planetary disk makes detection unlikely in existing or forming stellar/planetary systems.

  6. 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.

  7. Stress evolution during ultrasonic Al ribbon bonding

    NASA Astrophysics Data System (ADS)

    Ando, Masaya; Takashima, Kazumasa; Maeda, Masakatsu; Takahashi, Yasuo

    2014-08-01

    The present study reveals the stress distribution in the substrate during ultrasonic bonding. The deformations of the Si substrate, Al ribbon, and Al pad were numerically analyzed using a finite element method. Experimental observation of the interface using a highspeed video camera was also conducted to determine the actual interfacial slip amplitude. This amplitude becomes smaller than that of tool-tip with bonding time. It was suggested from the numerical simulations that frictional adhesion enhanced the friction force, resulting in an increase in the equivalent stress in the ribbon and pad. As a result, very large stresses occur in the substrate during ultrasonic bonding. These stresses evolve with the progress of ultrasonic bonding, i.e., frictional adhesion.

  8. 14th Annual ALS Users' Association meeting

    SciTech Connect

    Robinson, Art

    2001-11-29

    Sponsored by the Users' Executive Committee (UEC) and spread over three days from October 15-17, the fourteen annual ALS Users' Association Meeting featured an exceptional program with science as the main theme. While the first day was reserved for the traditional facility and Washington reports and for science highlights, the following two days, devoted to several workshops covering topics from theory to detectors, new experimental facilities, and forefront science, were strong draws. As a result, it should not be surprising that the number of registered attendees jumped to a record level of 352, more than 100 above the typical attendance in recent years. The successful commissioning of the long-awaited superconducting bend magnets, or superbends, in the ALS storage-ring lattice just before the meeting opened also helped stimulate interest.

  9. Antiferromagnetic behaviour of Tb2Al alloy

    NASA Astrophysics Data System (ADS)

    Rojas, D. P.; André, G.; Rodríguez Fernández, J.; Sánchez Marcos, J.; Fernández Barquín, L.; Echevarria, C.

    2011-10-01

    The structural, thermal and magnetic properties ol the Tb2Al alloy have been investigated by AC/DC magnetic susceptibility, specific heat, X-ray and neutron diffraction measurements. DC and AC-magnetic susceptibility results are consistent with an AFM order at TN = 52 K. The specific heat data show a lambda anomaly associated to the magnetic transition with a peak at 52 K (cord = 99 J/molTbK). The analysis of thermodiffractograms of neutron diffraction patterns indicates that, below the ordering temperature, the magnetic reflections can be indexed with a commensurate lattice related to the crystallographic cell (Pmna) by a propagation vector k = (1/2, 1/2, 1/2). The results are compared with those reported for other magnetic rare earth alloys of R2Al-type (with R = Nd, Gd and Dy).

  10. DFT study of Al doped armchair SWCNTs

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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).

  11. Polarized Cold Neutron Capture in ^27Al

    NASA Astrophysics Data System (ADS)

    Balascuta, Septimiu

    2013-04-01

    The NPDGamma Experiment at the Spallation Neutron Source at ORNL is measuring the parity-odd correlation between the neutron spin and the direction of the emitted photon in the capture of cold neutrons on a 16-liter liquid parahydrogen target. The goal is to determine the strength of the weak nucleon-nucleon interaction. One of the main background contributions comes from the gamma rays produced by neutrons captured in the Al walls of the target vessel. To quantify this effect a commissioning experiment measured the parity-odd and parity-even asymmetries in the angular distribution of the gamma rays from the capture of polarized cold neutrons in a solid Al target. A status of the analysis of this experiment will be presented.

  12. 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.

  13. 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.

  14. Psychosocial adjustment to ALS: a longitudinal study

    PubMed Central

    Matuz, Tamara; Birbaumer, Niels; Hautzinger, Martin; Kübler, Andrea

    2015-01-01

    For the current study the Lazarian stress-coping theory and the appendant model of psychosocial adjustment to chronic illness and disabilities (Pakenham, 1999) has shaped the foundation for identifying determinants of adjustment to ALS. We aimed to investigate the evolution of psychosocial adjustment to ALS and to determine its long-term predictors. A longitudinal study design with four measurement time points was therefore, used to assess patients' quality of life, depression, and stress-coping model related aspects, such as illness characteristics, social support, cognitive appraisals, and coping strategies during a period of 2 years. Regression analyses revealed that 55% of the variance of severity of depressive symptoms and 47% of the variance in quality of life at T2 was accounted for by all the T1 predictor variables taken together. On the level of individual contributions, protective buffering, and appraisal of own coping potential accounted for a significant percentage in the variance in severity of depressive symptoms, whereas problem management coping strategies explained variance in quality of life scores. Illness characteristics at T2 did not explain any variance of both adjustment outcomes. Overall, the pattern of the longitudinal results indicated stable depressive symptoms and quality of life indices reflecting a successful adjustment to the disease across four measurement time points during a period of about two years. Empirical evidence is provided for the predictive value of social support, cognitive appraisals, and coping strategies, but not illness parameters such as severity and duration for adaptation to ALS. The current study contributes to a better conceptualization of adjustment, allowing us to provide evidence-based support beyond medical and physical intervention for people with ALS. PMID:26441696

  15. Response to de la Iglesia et al.

    PubMed

    Yetish, Gandhi; Kaplan, Hillard; Gurven, Michael; Wood, Brian; Pontzer, Herman; Manger, Paul R; Wilson, Charles; McGregor, Ronald; Siegel, Jerome M

    2016-04-01

    We wish to respond to the commentary of de la Iglesia et al. [1]. Studies comparing sleep in different communities have different goals. One frequent goal has been to determine how sleep is affected by manipulating specific 'modern' conditions. Many studies have investigated the effect of artificial light and electronic entertainment. Such studies have clearly shown that light, particularly blue light, delays sleep onset [2]. Studying the effect of artificial light on sleep was not a goal of our study. PMID:27046810

  16. 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.

  17. Softening Kinetics in High Al and High Al-Nb-Microalloyed Steels

    NASA Astrophysics Data System (ADS)

    Pereda, B.; Aretxabaleta, Z.; López, B.

    2015-03-01

    Double-hit torsion tests were performed in order to study the effect of high Al levels (up to 2 wt.%) and Nb microalloying (up to 0.07 wt.%) on the static softening kinetics of 0.2%C-2%Mn steels. The addition of 1%Al leads to a delay in the softening kinetics due to solute-drag effect, equivalent to that exerted by 0.027%Nb. For the 2%Al steels, at temperatures below 1000 °C, γ → α phase transformation occurs after deformation, resulting in a larger retardation of the softening kinetics. At temperatures higher than 1000 °C, Nb in solid solution also contributes to the retardation of the static softening kinetics, and at lower temperatures NbC strain-induced precipitation leads to incomplete softening for the 1%Al steel, and to a complex interaction between softening, phase transformation, and NbC strain-induced precipitation for the 2%Al-Nb steels. The effect of Al on the static softening kinetics was quantified and introduced in a model developed in previous works for the prediction of the austenite microstructural evolution. In order to validate the results of the model, multipass torsion tests were carried out at conditions representative of hot strip and plate rolling mills. Model predictions show reasonable agreement with the results obtained at different deformation conditions.

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    Okumus, S. Cem; Karslioglu, Ramazan; Akbulut, Hatem

    2013-12-01

    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 Al2O3 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-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.

  20. 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.

  1. Room Temperature Radiolytic Synthesized Cu@CuAlO2-Al2O3 Nanoparticles

    PubMed Central

    Abedini, Alam; Saion, Elias; Larki, Farhad; Zakaria, Azmi; Noroozi, Monir; Soltani, Nayereh

    2012-01-01

    Colloidal Cu@CuAlO2-Al2O3 bimetallic nanoparticles were prepared by a gamma irradiation method in an aqueous system in the presence of polyvinyl pyrrolidone (PVP) and isopropanol respectively as a colloidal stabilizer and scavenger of hydrogen and hydroxyl radicals. The gamma irradiation was carried out in a 60Co gamma source chamber with different doses up to 120 kGy. The formation of Cu@CuAlO2-Al2O3 nanoparticles was observed initially by the change in color of the colloidal samples from colorless to brown. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of bonds between polymer chains and the metal surface at all radiation doses. Results of transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD) showed that Cu@CuAlO2-Al2O3 nanoparticles are in a core-shell structure. By controlling the absorbed dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increased precursor concentration and decreased with increased dose. This is due to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation. PMID:23109893

  2. Anomalous phonon properties in the silicide superconductors CaAlSi and SrAlSi

    NASA Astrophysics Data System (ADS)

    Kuroiwa, S.; Hasegawa, T.; Kondo, T.; Ogita, N.; Udagawa, M.; Akimitsu, J.

    2008-11-01

    Lattice-dynamical properties of CaAlSi and SrAlSi with a similar layer structure to MgB2 have been first investigated by both Raman-scattering and ab initio calculations. All Raman-active phonons with E' symmetry have been clearly observed for both compounds. Their line shapes are asymmetric but their linewidths are ˜10cm-1 , which is very narrower than that of MgB2 . In addition to the Raman-active modes, several extra peaks have been observed below 160cm-1 . These low-energy extra modes can be assigned to the out-of-plane vibrations of Al perpendicular to Al-Si basal plane. Since these peak intensities are strongly affected by the incident energy (resonance Raman process), the electronic state is important for them. Moreover, in both crystals of CaAlSi and SrAlSi, we point out the energy difference for the different propagation directions along the c axis and the c plane, in spite of the very close wave vector to the Brillouin-zone center. This energy difference cannot be explained by a usual Raman-scattering scenario at this stage.

  3. Redistribution of Ti and Al in deuterium charged TiAl

    SciTech Connect

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

    1992-06-01

    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. 10 refs.

  4. 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. PMID:16923240

  5. Energetic ion bombarded Fe/Al multilayers

    SciTech Connect

    Al-Busaidy, M.S.; Crapper, M.D.

    2006-05-15

    The utility of ion-assisted deposition is investigated to explore the possibility of counteracting the deficiency of back-reflected current of Ar neutrals in the case of lighter elements such as Al. A range of energetically ion bombarded Fe/Al multilayers sputtered with applied surface bias of 0, -200, or -400 V were deposited onto Si(111) substrates in an argon atmosphere of 4 mTorr using a computer controlled dc magnetron sputtering system. Grazing incidence reflectivity and rocking curve scans by synchrotron x rays of wavelength of 1.38 A were used to investigate the structures of the interfaces produced. Substantial evidence has been gathered to suggest the gradual suppression of interfacial mixing and reduction in interfacial roughness with increases of applied bias. The densification of the Al microstructure was noticeable and may be a consequence of resputtering attributable to the induced ion bombardment. The average interfacial roughnesses were calculated for the 0, -200, and -400 V samples to be 7{+-}0.5, 6{+-}0.5, and 5{+-}0.5 A respectfully demonstrating a 30% improvement in interface quality. Data from rocking curve scans point to improved long-range correlated roughness in energetically deposited samples. The computational code based on the recursive algorithm developed by Parratt [Phys. Rev. 95, 359 (1954)] was successful in the simulation of the specular reflectivity curves.

  6. 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. PMID:27117334

  7. Complete fusion of 15N+27Al

    NASA Astrophysics Data System (ADS)

    Prosser, F. W., Jr.; Racca, R. A.; Daneshvar, K.; Geesaman, D. F.; Henning, W.; Kovar, D. G.; Rehm, K. E.; Tabor, S. L.

    1980-05-01

    The total fusion cross section for the system 15N + 27Al has been measured over an energy range 27 MeV<=Elab<=70 MeV by detection of the fusion-evaporation residues. In addition elastic scattering was measured at six energies and fitted by optical model calculations. The fusion cross section for the system saturates at 1150+/-50 mb. The data can be well described by the model of Glas and Mosel, using a reasonable set of parameters. The model of Horn and Ferguson also describes the data well if an appropriate charge radius is used. Comparison is made between these results and the fusion cross sections for 16O + 26Mg and 18O + 24Mg, which lead to the same compound nucleus. The results for 15N + 27Al are quite similar to those for 18O + 24Mg, and the differences between the fusion cross sections for these two systems and those for 16O + 26Mg may be evidence for an entrance channel effect. NUCLEAR REACTIONS 15N+27Al, Elab=27-70 MeV; measured σfusion(E) measured dσdΩ elastic scattering; data fitted with Glas and Mosel model, Horn and Ferguson model.

  8. 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.

  9. 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.

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

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Smialek, J. L.; Barrett, C. A.

    1989-01-01

    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-Al203 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.

  11. 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.

  12. The Nature of Interfaces in Al-1050/Al-1050 and Al-1050/Mg-AZ31 Couples Joined by Magnetic Pulse Welding (MPW)

    NASA Astrophysics Data System (ADS)

    Stern, A.; Aizenshtein, M.; Moshe, G.; Cohen, S. R.; Frage, N.

    2013-07-01

    The microstructure and the phase composition of the interfaces of Al-1050/Al-1050 and Al-1050/Mg-AZ31 magnetic pulse welding (MPW) joints were characterized by SEM and TEM analyses. The mechanical properties were tested by nanoindentation. Properties of the Al-1050/Al-1050 interface joint were established. The interface is almost free from Al3Fe precipitates, which are present in the base metal. The hardness value is higher than that of the base metal; however, values of the Young's modulus of the interface and base metal are similar. It was suggested that the interface evolution in the Al-1050/Al-1050 system includes local melting and rapid solidification of the base materials. A wavy shaped heterogeneous interface was detected in the Al-1050/Mg-AZ31 joints. Some areas are free from visible intermetallic phases (IMPs), while others contain pockets of relatively coarse intermetallic precipitates. The presence of a relatively large fraction of globular porosity at the interface indicates that local melting takes place in the course of MPW. TEM characterization of regions free of IMPs at the interface reveals regions consisting of fcc supersaturated Al-Mg solid solution, apparently formed as a result of local mechanical alloying during MPW. In other regions, the composition and structure correspond to the Mg17Al12 phase, which was probably formed by local melting and rapid solidification.

  13. Short-period superlattices of AlN/Al{sub 0.08}Ga{sub 0.92}N grown on AlN substrates

    SciTech Connect

    Nikishin, S.A.; Borisov, B.A.; Chandolu, A.; Kuryatkov, V.V.; Temkin, H.; Holtz, M.; Mokhov, E.N.; Makarov, Yu.; Helava, H.

    2004-11-08

    High-quality short-period superlattices of AlN/Al{sub 0.08}Ga{sub 0.92}N have been grown by gas-source molecular-beam epitaxy with ammonia on Al face of AlN (0001) substrates. A significant reduction was achieved in the dislocation density, down to 3x10{sup 8} cm{sup -2}. Complete removal of residual Al{sub 2}O{sub 3} surface oxide is needed in order to obtain low dislocation density in homoepitaxy on AlN. We show that the presence of Al{sub 2}O{sub 3} islands with the surface coverage as low as 0.2% results in increased dislocation density.

  14. Chemical ordering and large tunnel magnetoresistance in Co2FeAl/MgAl2O4/Co2FeAl(001) junctions

    NASA Astrophysics Data System (ADS)

    Scheike, Thomas; Sukegawa, Hiroaki; Inomata, Koichiro; Ohkubo, Tadakatsu; Hono, Kazuhiro; Mitani, Seiji

    2016-05-01

    Epitaxial magnetic tunnel junctions (MTJs) with a Co2FeAl/CoFe (0.5 nm)/MgAl2O4/Co2FeAl(001) structure were fabricated by magnetron sputtering. High-temperature in situ annealing led to a high degree of B2-order in the Co2FeAl layers and cation order of the MgAl2O4 barrier. Large tunnel magnetoresistance (TMR) of up to 342% was obtained at room temperature (616% at 4 K), in contrast to the TMR ratio ( ≲ 160%) suppressed by the band-folding effect in Fe/cation-ordered MgAl2O4/Fe MTJs. The present study reveals that the high degree of B2-order and the resulting high spin polarization in the Co2FeAl electrodes enable us to bypass the band-folding problem in spinel barriers.

  15. 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.

  16. 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

    ... Matter of the Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al-Jihad, aka... fi Bilad al-Rafidayn, aka The Organization of al-Jihad's Base of Operations in Iraq, aka al-Qaida of Jihad in Iraq, aka al-Qaida in Iraq, aka al-Qaida in Mesopotamia, aka al-Qaida in the Land of the...

  17. Elevated temperature wear of Al6061 and Al6061-20%Al{sub 2}O{sub 3}

    SciTech Connect

    Singh, J.; Alpas, A.T.

    1995-04-01

    Both current and potential applications of particulate reinforced aluminum alloys involve components which are required to operate under sliding contact conditions at elevated temperatures. Examples include brake rotors, piston and cylinder liners in automotive engines where operating temperatures can reach 0.5--0.8 of the melting temperature of the matrix alloy. For this reason, study of the high temperature wear resistance of aluminum alloys reinforced by Al{sub 2}O{sub 3} or SiC particles is important. These studies are also of interest for the problem of die wear during hot extrusion of aluminum matrix composites and to rationalize the process of frictional welding involved in joining of the composites. Although the room temperature tribological and mechanical behaviors of aluminum matrix composites have received considerable attention, their high temperature properties have only recently started being considered. It has been shown that Al-Si-Mg (A356) alloys with or without SiC particles show a transition from mild to severe wear when a critical temperature (at about 0.4 T{sub m}, where T{sub m} is the melting temperature of aluminum) is reached as a result of frictional heating under dry sliding conditions. In this work, high temperature wear of A16061 and A16061-20%Al{sub 2}O{sub 3} was studied at temperatures between 25--500 C. The microstructural changes that occurred during wear have been delineated in order to understand the wear mechanisms that operate at high temperatures.

  18. 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.

  19. Interfacial microstructure and growth mechanism of Al4C3 in Grf/Al composites fabricated by liquid pressure method.

    PubMed

    Xu, Wang; Chenchong, Wang; Zhichao, Zhang; Ping, Liang; Yanhua, Shi; Guofu, Zhang

    2014-10-01

    In this study, Grf/Al composite was fabricated by liquid pressure method. The diffusion layer and the nucleation and growth of Al4C3 were observed at the interface of Grf/Al composites by TEM and HRTEM. The growth mechanism of Al4C3 was analyzed in detail by crystallography theory. It was found that Al4C3 had no phase relations with the carbon fiber. (0001) layer of Al4C3 was parallel with main growth direction. Both the diffusion layer at the interface and crystal structure of Al4C3 affected the shape of Al4C3. At a certain position, Al4C3 could connect two fibers when the fibers were close to each other. PMID:25041826

  20. Influence of Reaction with XeF2 on Surface Adhesion of Al and Al2O3 Surfaces

    SciTech Connect

    Zhang, Tianfu; Park, Jeong Y.; Huang, Wenyu; Somorjai, Gabor A.

    2008-07-28

    The change of surface adhesion after fluorination of Al and Al{sub 2}O{sub 3} surfaces using XeF{sub 2} was investigated with atomic force microscopy. The chemical interaction between XeF{sub 2} and Al and Al{sub 2}O{sub 3} surfaces was studied by in situ x-ray photoelectron spectroscopy. Fresh Al and Al{sub 2}O{sub 3} surfaces were obtained by etching top silicon layers of Si/Al and Si/Al{sub 2}O{sub 3} with XeF{sub 2}. The surface adhesion and chemical composition were measured as a function of time after the exposure to air or annealing (at 200 C under vauum). The correlation between the adhesion force increase and presence of AlF{sub 3} on the surface was revealed.

  1. Fabrication of Al/Al3Ti Functionally Graded Materials by Reaction Centrifugal Mixed-Powder Method

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    Formation of compositional gradient in Al/Al3Ti Functionally graded materials (FGMs) fabricated by the centrifugal method (CM) depends mainly on the centrifugal force and the processing temperature. In this study, a novel centrifugal method, reaction centrifugal mixed-powder method (RCMPM), was proposed to fabricate Al/Al3Ti FGMs under fixed centrifugal force (G=80). The effects of RCMPM processing temperature on the formation of Al3Ti intermetallics, its morphology and its distribution in the fabricated Al/Al3Ti FGMs have been investigated. Fine granular Al3Ti were observed at relatively lower processing temperature while the known coarse platelet-like particles of Al3Ti could be achieved at higher casting temperatures. Moreover, Ti3Al intermetallics compound and unreacted Ti phases are also observed along with Al3Ti particles. In addition, distribution of Al3Ti intermetallics size and their volume fraction showed a significant change when the Al/Al3Ti FGMs processed at different temperatures relative to the liquidus temperature of the master alloy.

  2. Transplacental passage of 26Al from pregnant rats to fetuses and 26Al transfer through maternal milk to suckling rats

    NASA Astrophysics Data System (ADS)

    Yumoto, S.; Nagai, H.; Matsuzaki, H.; Kobayashi, T.; Tada, W.; Ohki, Y.; Kakimi, S.; Kobayashi, K.

    2000-10-01

    Aluminium (Al) is toxic to the growth of fetuses and sucklings. However, the incorporation of Al into fetuses and sucklings in the periods of gestation and lactation has not been well clarified because Al lacks a suitable isotope for a tracer experiment. In this study, we used 26Al (a radioisotope of Al with half-life of 716,000 yr) as a tracer, and measured 26Al incorporation into fetuses and sucklings by accelerator mass spectrometry (AMS). To investigate Al incorporation into fetuses through transplacental passage, 26Al ( 26AlCl 3) was subcutaneously injected into pregnant rats on day 15 of gestation. 26Al was also subcutaneoulsy injected into lactating rats from day 1 to day 20 postpartum. By day 20 of gestation, 0.2% of the 26Al injected into a pregnant rat had been transferred to the fetuses, and 26Al was detected in the brain and liver of the fetuses. On day 9 postpartum, high levels of 26Al were demonstrated in the brain, liver, kidneys and blood of suckling rats. It is concluded that 26Al subcutaneously injected into pregnant rats and/or lactating rats is incorporated into their offspring through transplacental passage and/or maternal milk.

  3. Hot Corrosion Performance of AlO-CrO/NiCoCrAlYTa and AlO/NiCoCrAlYTa Coatings Deposited by Atmospheric Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Tao, Chong; Wang, Lei; Cheng, Nailiang; Hu, Hengfa; Liu, Yang; Song, Xiu

    2016-04-01

    AlO-CrO/NiCoCrAlYTa and AlO/NiCoCrAlYTa coatings were deposited on 316L stainless steel substrate using atmospheric plasma spraying, respectively, in order to improve the oxidation and corrosion resistance. The hot corrosion performance of the coatings at 700 and 900 °C were studied, and the detailed microstructures and phase composition of the coatings were analyzed using x-ray diffraction, scanning electron microscope with energy dispersive spectrometer, and transmission electron microscope. The results show that both coatings are structurally featured by slatted layers, consisting of amorphous phase, Cr2O3, Ni3Al, and Al2O3. The hot corrosion resistance of AlO-CrO/NiCoCrAlYTa coating is better than that of AlO/NiCoCrAlYTa coating. This improvement is attributed to lower porosity and more compact Cr2O3 in AlO-CrO/NiCoCrAlYTa coating which performs better than Al2O3 in blocking further inward progress of corrosion and oxidization.

  4. First-principles studies of Al-Ni intermetallic compounds

    SciTech Connect

    Shi Dongmin; Wen Bin; Melnik, Roderick; Yao Shan; Li Tingju

    2009-10-15

    The structural properties, heats of formation, elastic properties, and electronic structures of Al-Ni intermetallic compounds are analyzed here in detail by using density functional theory. Higher calculated absolute values of heats of formation indicate a very strong chemical interaction between Al and Ni for all Al-Ni intermetallic compounds. According to the computational single crystal elastic constants, all the Al-Ni intermetallic compounds considered here are mechanically stable. The polycrystalline elastic modulus and Poisson's ratio have been deduced by using Voigt, Reuss, and Hill (VRH) approximations, and the calculated ratio of shear modulus to bulk modulus indicated that AlNi, Al{sub 3}Ni, AlNi{sub 3} and Al{sub 3}Ni{sub 5} compounds are ductile materials, but Al{sub 4}Ni{sub 3} and Al{sub 3}Ni{sub 2} are brittle materials. With increasing Ni concentration, the bulk modulus of Al-Ni intermetallic compounds increases in a linear manner. The electronic energy band structures confirm that all Al-Ni intermetallic compounds are conductors. - Graphical abstract: Calculated bulk modulus compared to experimental and other theoretical values for the Al-Ni intermetallic compounds.

  5. Theory and X-ray Absorption Spectroscopy for Aluminum Coordination Complexes – Al K-Edge Studies of Charge and Bonding in (BDI)Al, (BDI)AlR2, and (BDI)AlX2 Complexes.

    PubMed

    Altman, Alison B; Pemmaraju, C D; Camp, Clément; Arnold, John; Minasian, Stefan G; Prendergast, David; Shuh, David K; Tyliszczak, Tolek

    2015-08-19

    Polarized aluminum K-edge X-ray absorption near edge structure (XANES) spectroscopy and first-principles calculations were used to probe electronic structure in a series of (BDI)Al, (BDI)AlX2, and (BDI)AlR2 coordination compounds (X = F, Cl, I; R = H, Me; BDI = 2,6-diisopropylphenyl-β-diketiminate). Spectral interpretations were guided by examination of the calculated transition energies and polarization-dependent oscillator strengths, which agreed well with the XANES spectroscopy measurements. Pre-edge features were assigned to transitions associated with the Al 3p orbitals involved in metal-ligand bonding. Qualitative trends in Al 1s core energy and valence orbital occupation were established through a systematic comparison of excited states derived from Al 3p orbitals with similar symmetries in a molecular orbital framework. These trends suggested that the higher transition energies observed for (BDI)AlX2 systems with more electronegative X(1-) ligands could be ascribed to a decrease in electron density around the aluminum atom, which causes an increase in the attractive potential of the Al nucleus and concomitant increase in the binding energy of the Al 1s core orbitals. For (BDI)Al and (BDI)AlH2 the experimental Al K-edge XANES spectra and spectra calculated using the eXcited electron and Core-Hole (XCH) approach had nearly identical energies for transitions to final state orbitals of similar composition and symmetry. These results implied that the charge distributions about the aluminum atoms in (BDI)Al and (BDI)AlH2 are similar relative to the (BDI)AlX2 and (BDI)AlMe2 compounds, despite having different formal oxidation states of +1 and +3, respectively. However, (BDI)Al was unique in that it exhibited a low-energy feature that was attributed to transitions into a low-lying p-orbital of b1 symmetry that is localized on Al and orthogonal to the (BDI)Al plane. The presence of this low-energy unoccupied molecular orbital on electron-rich (BDI)Al distinguishes

  6. Revisiting the Al/Al2O3 Interface: Coherent Interfaces and Misfit Accommodation

    PubMed Central

    Pilania, Ghanshyam; Thijsse, Barend J.; Hoagland, Richard G.; Lazić, Ivan; Valone, Steven M.; Liu, Xiang-Yang

    2014-01-01

    We study the coherent and semi-coherent Al/α-Al2O3 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 at 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. 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-Al2O3 composite heterostructures. PMID:24670940

  7. 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.

  8. Tribological Properties of Ti(Al,O)/Al2O3 Composite Coating by Thermal Spraying

    NASA Astrophysics Data System (ADS)

    Salman, Asma; Gabbitas, Brian; Cao, Peng; Zhang, Deliang

    The use of thermal spray coatings provides protection to the surfaces operating in severe environments. The main goal of the current work is to investigate the possibility of using a high velocity air fuel (HVAF) thermally sprayed wear resistant Ti(Al,O)/Al2O3 coating on tool steel (H13) which is used for making dies for aluminium high pressure die casting and dummy blocks aluminium extrusion. A feedstock of Ti(Al,O)/Al2O3 composite powder was produced from a mixture of Al and TiO2 powders by high energy mechanical milling, followed by a thermal reaction process. The feedstock was then thermally sprayed using a high velocity air-fuel (HVAF) technique onto H13 steel substrates to produce a composite coating. The present study describes and compares the tribological properties such as friction and sliding wear rate of the coating both at room and high temperature (700°C). The wear resistance of the coating was investigated by a tribometer using a spherical ended alumina pin as a counter body under dry and lubricating conditions. The results showed that composite coating has lower wear rate at high temperature than at room temperature without using lubricant. The composite coating was characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD). This paper reports the experimental observations and discusses the wear resistance performance of the coatings at room and high temperatures.

  9. Microstructure evolution and properties of Al/Al-Mg-Si alloy clad wire during heat treatment

    NASA Astrophysics Data System (ADS)

    Wang, Xiang; Guan, Ren-guo; Zhang, Yang; Su, Ning; Ji, Lian-ze; Li, Yuan-dong; Chen, Ti-jun

    2016-06-01

    In this paper, heat treatment was carried out on Al/Al-Mg-Si alloy clad wire, and microstructure evolution and properties of Al/Al-Mg-Si alloy clad wire during heat treatment were investigated. During solution, contents of Mg and Si in inner matrix increased due to dissolution of primary Mg2Si, and they also increased in outer matrix because Mg and Si diffused across the interface. Tensile strength of the clad wire increased firstly and then decreased, and elongation continuously increased, while conductivity continuously decreased with the increase in solution time. In aging process, Mg2Si precipitated in both inner core and outer layer, and the content and average diameter of the precipitate increased with the increase in aging time. The content of precipitate was higher, and the average diameter was bigger in inner core. Tensile strength of the clad wire increased firstly and then decreased with the increase in aging time, and the elongation continuously decreased, while the conductivity continuously increased. The peak tensile strength of 202 MPa occurred at 8 h, when the corresponding elongation was 20 % and the conductivity reached 56.07 %IACS. Even tensile strength of the prepared clad wire approximately equaled to that of Al-0.5Mg-0.35Si alloy 203 MPa, the conductivity was obviously improved from 54.2 to 56.07 %IACS.

  10. Revisiting the Al/Al2O3 Interface: Coherent Interfaces and Misfit Accommodation

    DOE PAGESBeta

    Pilania, Ghanshyam; Thijsse, Barend J.; Hoagland, Richard G.; Lazić, Ivan; Valone, Steven M.; Liu, Xiang-Yang

    2014-03-27

    We report the coherent and semi-coherent Al/α-Al2O3 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 at the interface.more » 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-Al2O3 composite heterostructures.« less

  11. Transformation to Ni5Al3 in a 63.0 at. pct Ni-Al alloy

    NASA Technical Reports Server (NTRS)

    Khadkikar, P. S.; Locci, I. E.; Vedula, K.; Michal, G. M.

    1993-01-01

    Microstructures of 63 at. pct P/M Ni-Al alloys with a composition close to the stoichiometry of the Ni5Al3 phase were investigated using homogenized and quenched specimens aged at low temperatures for various times. Results of analyses of XRD data and electron microscopy observations were used for quantitative phase analysis, performed to calculate the (NiAl + Ni5Al3)/Ni5Al3 phase boundary locations. The measured lattice parameters of Ni5Al3 phase formed at 823, 873, and 923 K indicated an increase in tetragonality of the phase with increasing nickel content.

  12. 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.

  13. Growth and characterization of TiAlN/CrAlN superlattices prepared by reactive direct current magnetron sputtering

    SciTech Connect

    Barshilia, Harish C.; Deepthi, B.; Rajam, K. S.; Bhatti, Kanwal Preet; Chaudhary, Sujeet

    2009-01-15

    TiAlN and CrAlN coatings were prepared using a reactive direct current magnetron sputtering system from TiAl and CrAl targets. Structural characterization of the coatings using x-ray diffraction (XRD) revealed the B1 NaCl structure of TiAlN and CrAlN coatings with a prominent reflection along the (111) plane. The XPS data confirmed the bonding structures of TiAlN and CrAlN single layer coatings. Subsequently, nanolayered multilayer coatings of TiAlN/CrAlN were deposited on silicon and mild steel (MS) substrates at different modulation wavelengths ({lambda}) with a total thickness of approximately 1.0 {mu}m. The modulation wavelengths were calculated from the x-ray reflectivity data using modified Bragg's law. TiAlN/CrAlN multilayer coatings were textured along (111) for {lambda}<200 A and the XRD patterns showed the formation of superlattice structure for coatings deposited at {lambda}=102 A. The x-ray reflectivity data showed reflections of fifth and seventh orders for multilayer coatings deposited at {lambda}=102 and 138 A, respectively, indicating the formation of sharp interfaces between TiAlN and CrAlN layers. The cross-sectional scanning electron microscopy image of TiAlN/CrAlN multilayer coatings indicated a noncolumnar and dense microstructure. A maximum hardness of 39 GPa was observed for TiAlN/CrAlN multilayer coatings deposited at {lambda}=93 A, which was higher than the rule-of-mixture value (30 GPa) for TiAlN and CrAlN. Study of thermal stability of the coatings in air using micro-Raman spectroscopy indicated that the TiAlN/CrAlN multilayer coatings were stable up to 900 deg. C in air. TiAlN/CrAlN multilayer coatings also exhibited improved corrosion resistance when compared to the MS substrate.

  14. ALS 2883: Analysis of spectroscopic features

    NASA Astrophysics Data System (ADS)

    Silva, A. R.; Levenhagen, R. S.; Künzel, R.; Leister, N. V.

    2014-10-01

    ALS 2883 (RA 13^{h} 02^{m} 47^{s}, DEC -63^{o} 50' 08'', M_{v} 10.1) is the first known radio pulsar with an emission B-type companion system, discovered in 1992. The Be companion of ALS 2883 has all line profiles in the visible range in emission. This emission is a common hallmark among many Be stars, and this effect is thought to be due to the presence of a circumstellar environment. Also, the star is orbiting a X-ray source as has been detected by the XMM-Newton Science Operation Center. In this study, we present the observations of ALS 2883 made at the OPD/LNA 1.60 m telescope with the Coudé spectrograph in the range 4000 to 5000 Å and S/N simeq 200, performed in April 2011. First-order estimations of T_{eff} and log g parameters have been performed through Johnson's UBV and JHK photometric calibrations. Projected rotation velocity V sin i has been estimated through the mean of the first zeroes of the Fourier transforms of neutral helium rotation profiles adopting linear, quadratic and square-root limb-darkening laws. The physical conditions of the circumstellar envelope were estimated through the solution of the radiative transport equation assuming local thermodynamic equilibrium within a disk-shaped circumstellar environment with a Keplerian velocity field. The radiative transport equation is solved assuming the Roche model as a boundary condition in the circumstellar environment. Iterating the computations with a downhill-simplex algorithm, this analysis leads to a best solution for an envelope with T simeq 9500 K, gas density ρ simeq 2 × 10^{-15} g.cm^{-3}, internal radius r_{i} simeq 8 R_{odot} and external radius r_e simeq 30 R_{odot}, rotating with V_{rot} simeq 140 km.s^{-1} and expanding with V_{exp} simeq 90 km.s^{-1}.

  15. 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.

  16. Orbit stability of the ALS storage ring

    SciTech Connect

    Keller, R.; Nishimura, H.; Biocca, A.

    1997-05-01

    The Advanced Light Source (ALS) storage ring, a synchrotron light source of the third generation, is specified to maintain its electron orbit stable within one tenth of the rms beam size. In the absence of a dedicated orbit feed-back system, several orbit-distorting effects were investigated, aided by a new interactive simulation tool, the code TRACY V. The effort has led to a better understanding of the behavior of a variety of accelerator subsystems and in consequence produced a substantial improvement in day-to-day orbit stability.

  17. Ferromagnetic Fe2CrAl Nanowires

    NASA Astrophysics Data System (ADS)

    Dulal, Rajendra; Dahal, Bishnu; Pegg, Ian L.; Philip, John

    Heusler alloy Fe2CrAl (FCA) nanowires were grown on silicon substrates. Nanowires have diameters in the range 50 to 200 nm and lengths up to 100 µm. They exhibit cubic L21 and A2 type structure with a space group, Pm m. Magnetic characterization reveals that they display ferromagnetic behavior and has a Curie temperature above 400 K. Magnetic behavior of FCA nanowires is different from the reported bulk behavior. Bulk FCA with L21 structure has a Curie temperature around 274 K. National Science Foundation under ECCS-0845501 and NSF-MRI, DMR-0922997.

  18. Generation of Al nanoparticles via ablation of bulk Al in liquids with short laser pulses.

    PubMed

    Stratakis, Emmanuel; Barberoglou, Marios; Fotakis, Costas; Viau, Guillaume; Garcia, Cecile; Shafeev, Georgy A

    2009-07-20

    Highly stable aluminum nanoparticles (NPs) are generated via ablation of bulk Al in ethanol using either femtosecond (fs) or picosecond (ps) laser sources. The colloidal NPs solutions obtained with fs pulses exhibit a yellow coloration and show an increased optical absorption between 300 and 400 nm, tentatively assigned to the plasmon resonance of nanosized Al. The corresponding solutions after ps ablation are gray colored and opalescent. The average size of the NPs formed ranges from 20 nm for the fs case to 60 nm for the ps case, while a narrower distribution is obtained using the shorter pulses. High Resolution Transmission Electron Microscopy (HRTEM) studies indicate that the NPs are mostly amorphous with single crystalline inclusions. Al NPs generated with short laser pulses slowly react with air oxygen due to the presence of a native oxide cladding, which efficiently passivates their surface against further oxidation. PMID:19654669

  19. Energy localization on the Al sublattice of Pt3Al with L12 order

    SciTech Connect

    Medvedev, Nikolay N; Starostenkov, Mikhail D; Manley, Michael E

    2013-01-01

    A three-dimensional molecular-dynamics model of with order was developed and found to support the excitation of discrete breathers (DBs) and energy localization on the Al sublattice. For an initial lattice temperature of 0 K, large-amplitude DBs polarized along [100] are found to be very weakly damped, retaining most of their initial energy for more than 2000 cycles, while DBs polarized along [111] damped out over ~30 cycles. Because the DBs and their dissipation channels are confined to the Al sublattice, long-lived nonequilibrium states with large energy differences between the Al and Pt sublattices occur. Since collisions during irradiation more efficiently generate lattice vibrations in light atoms than heavy atoms, such nonequilibrium states may occur and alter the relaxation processes occurring during radiation damage.

  20. Epitaxial Zintl aluminide SrAl4 grown on a LaAlO3 substrate

    NASA Astrophysics Data System (ADS)

    Schlipf, Lukas; Slepko, Alexander; Posadas, Agham B.; Seinige, Heidi; Dhamdhere, Ajit; Tsoi, Maxim; Smith, David J.; Demkov, Alexander A.

    2013-07-01

    Zintl phases are a class of intermetallic materials that have simultaneously ionic and covalent bonding resulting from charge transfer between two different atomic species. We present a combined first principles and experimental study of Zintl-phase SrAl4, which is grown in thin film form on the perovskite oxide LaAlO3 using molecular beam epitaxy. The structural properties are investigated using reflection-high-energy electron diffraction, x-ray diffraction, and cross-section transmission electron microscopy, which reveal relaxed epitaxial island growth. Photoelectron spectroscopy measurements verify the Zintl-Klemm nature of the bonding in the material and are utilized to determine the band offset and the work function of SrAl4, while transport measurements confirm its metallic behavior. The experimentally observed properties are confirmed using density functional calculations.

  1. Local stress-induced effects on AlGaAs/AlOx oxidation front shape

    NASA Astrophysics Data System (ADS)

    Chouchane, F.; Almuneau, G.; Cherkashin, N.; Arnoult, A.; Lacoste, G.; Fontaine, C.

    2014-07-01

    The lateral oxidation of thick AlGaAs layers (>500 nm) is studied. An uncommon shape of the oxide tip is evidenced and attributed to the embedded stress distribution, inherent to the oxidation reaction. Experimental and numerical studies of the internal strain in oxidized AlxGa1-xAs/GaAs structures were carried out by dark-field electron holography and finite element methods. A mapping of the strain distribution around the AlGaAs/oxide interface demonstrates the main role of internal stress on the shaping of the oxide front. These results demonstrate the high relevance of strain in oxide-confined III-V devices, in particular, with over-500-nm thick AlOx confinement layers.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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.

  3. 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.

  4. Inferred Initial 26Al/27Al Ratios in Presolar Stardust Grains from Supernovae are Higher than Previously Estimated

    NASA Astrophysics Data System (ADS)

    Groopman, Evan; Zinner, Ernst; Amari, Sachiko; Gyngard, Frank; Hoppe, Peter; Jadhav, Manavi; Lin, Yangting; Xu, Yuchen; Marhas, Kuljeet; Nittler, Larry R.

    2015-08-01

    We performed an in-depth exploration of the Al-Mg system for presolar graphite, SiC, and Si3N4 grains found to contain large excesses of 26Mg, indicative of the initial presence of live 26Al. Ninety of the more than 450 presolar grains processed in this study contain well-correlated {δ }26{Mg}{/}24{Mg} and 27Al/24Mg ratios, derived from Nano-scale Secondary Ion Mass Spectrometer depth profiles, whose isochron-like regression lines yield inferred initial {}26{Al}{/}27{Al} ratios that, on average, are ˜1.5-2 times larger than the ratios previously reported for the grains. The majority of presolar graphite and SiC grains are heavily affected by Al contamination, resulting in large negative {δ }26{Mg}{/}24{Mg} intercepts of the isochron lines. Al contamination is potentially due to etching of the grains’ surfaces and subsequent capture of dissolved Al during the acid dissolution of their meteorite host rocks. From the isochron fits, the magnitude of Al contamination was quantified for each grain. The amount of Al contamination on each grain was found to be random and independent of grain size, following a uniform distribution with an upper bound at 59% contamination. The Al contamination causes conventional whole-grain estimates to underpredict the initial {}26{Al}{/}27{Al} ratios. The presolar grains with the highest {}26{Al}{/}27{Al} ratios are from Type II supernovae whose isochron-derived initial {}26{Al}{/}27{Al} ratios greatly exceed those predicted in the He/C and He/N zones of SN models.

  5. ALS1 and ALS3 gene expression and biofilm formation in Candida albicans isolated from vulvovaginal candidiasis

    PubMed Central

    Roudbarmohammadi, Shahla; Roudbary, Maryam; Bakhshi, Bita; Katiraee, Farzad; Mohammadi, Rasoul; Falahati, Mehraban

    2016-01-01

    Background: A cluster of genes are involved in the pathogenesis and adhesion of Candida albicans to mucosa and epithelial cells in the vagina, the important of which is agglutinin-like sequence (ALS) genes. As well as vaginitis is a significant health problem among women, the antifungal resistance of Candida species is continually increasing. This cross-sectional study investigates the expression of ALS1 and ALS3 genes and biofilm formation in C. albicans isolate isolated from vaginitis. Materials and Methods: Fifty-three recognized isolates of C. albicans were collected from women with recurrent vulvovaginal candidiasis in Iran, cultured on sabouraud dextrose agar, and then examined for gene expression. Total messenger RNA (mRNA) extracted from C. albicans isolates and complementary DNA synthesized using reverse transcriptase enzyme. Reverse transcription-polymerase chain reaction (RT-PCR) using specific primer was used to evaluate the expression of ALS1 and ALS3 through housekeeping (ACT1) genes. 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2H-tetrazolium bromide assay was performed to assess adherence capacity and biofilm formation in the isolated. Results: Forty isolates (75.8%) expressed ALS1 and 41 isolates (77.7%) expressed ALS3 gene. Moreover, 39 isolates (74%) were positive for both ALS1 and ALS3 mRNA by the RT-PCR. Adherence capability in isolates with ALS1 or ALS3 genes expression was greater than the control group (with any gene expression), besides, it was significantly for the most in the isolates that expressed both ALS1 and ALS3 genes simultaneously. Conclusion: The results attained indicated that there is an association between the expression of ALS1 and ALS3 genes and fluconazole resistance in C. albicans. A considerable percent of the isolates expressing the ALS1 and ALS3 genes may have contributed to their adherence to vagina and biofilm formation. PMID:27376044

  6. 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.

  7. Effect of Al on the Wetting Behavior Between TiC x and Molten Ti-Al Alloys

    NASA Astrophysics Data System (ADS)

    Liu, Xuyang; Lv, Xuewei; Dong, Hongbiao; Li, Chunxin; Bai, Chenguang

    2015-10-01

    The wetting behavior and the interfacial reactions between TiC x substrate and molten Ti-Al alloys with different Al contents were studied using the Sessile Drop method at 1758 K (1485 °C) in argon atmosphere. It is found that the wettability and interface reaction products depend on Al content in the molten alloy. The initial contact angles between the molten Ti-Al alloy and TiC0.78 surface reduces from 110 to 80 deg when Al content in the alloy changes from 40 to 80 wt pct. The reduction in the initial contact angle is due to the decrease of surface tension of the molten Ti-Al alloys with increasing Al contents. The segregation of Al atoms to the surface occurred at all bulk concentrations of Ti-Al alloys. Al with lower surface tension tends to segregate on the surface of liquid Ti-Al alloy. In the spreading stage, the interfacial reaction led to the decrease in the contact angle. The adhesion in Ti-Al/TiC x system can be interpreted in terms of strong chemical interactions, which is greatly affected by the diffusion of C. The equilibrium contact angle was measured less than 10 deg. Finally, the reaction sequence at the Ti-Al melt and TiC x substrate interface is proposed.

  8. Simulation Study of Al-1Mn/Al-10Si Circular Clad Ingots Prepared by Direct Chill Casting

    NASA Astrophysics Data System (ADS)

    Wu, Li; Kang, Huijun; Chen, Zongning; Fu, Ying; Wang, Tongmin

    2016-02-01

    A modified direct chill casting process based on Novelis FusionTM Technology co-casting process was used recently to prepare Al-1Mn/Al-10Si circular clad ingots. In the current study, a comprehensive simulation model was developed to investigate the direct chill casting process for preparing the Al-1Mn/Al-10Si circular clad ingots, and a parametric study and experimental research of the direct chill casting process was conducted to explore potential success and failure casting conditions. The simulation results revealed the bonding mechanism of the Al-1Mn/Al-10Si interface in the direct chill casting process and identified the effect of certain parameters on casting performance. The results indicated that the effect of casting speed and Al-1Mn casting temperature on the variations of the minimum solid fraction of Al-1Mn at the interface is stronger than that of cooling water flow rate in inner mold, while Al-10Si casting temperature is the weakest of the four casting parameters. The corresponding experimental results verified that Al-1Mn/Al-10Si circular clad ingot with acceptable metallurgical bonding can be successfully prepared by direct chill casting process under the proper casting parameters. The thickness of diffusion zone is about 40 μm, and the fractured position in tensile test was located in the Al-1Mn alloy side which indicated the strength of the interfacial region is higher than that of Al-1Mn alloy.

  9. Comparison on the interaction of Al3+/nano-Al13 with calf thymus DNA /salmon sperm DNA

    NASA Astrophysics Data System (ADS)

    Ma, Fei; Ma, Yue; Du, Changwen; Yang, Xiaodi; Shen, Renfang

    2015-11-01

    The conformation change, binding mode and binding site between Al3+/nano-Al13 and calf thymus DNA/salmon sperm DNA were investigated by UV-vis absorption, FTIR spectra, Raman spectroscopy and CD spectra, as well as melting curves measurement. The UV-vis spectra and circular dichroism spectra results suggested that the phosphate group structure was changed when Al3+ interacted with DNA, while the double-helix was distorted when nano-Al13 interacted with DNA. The FTIR and Raman spectroscopy revealed that the binding sites were Al3+ … PO2, Al3+ … N7/guanine PO2 … Al13 … N7-C8/guanine with calf thymus DNA, and Al3+ … N3-O2/cytosine, Al3+ … N7-C8/guanine, PO2 … Al13 … N7-C8/guanine, PO2 … Al13 … N1/adenine with salmon sperm DNA, respectively. The electrostatic binding was existed between Al3+ and DNA, and the electrostatic binding and complexing were found between nano-Al13 and DNA.

  10. Ni-Al2O3 and Ni-Al composite high-aspect-ratio microstructures

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Sorrell, Melford; Kelly, Kevin W.; Ma, Evan

    1998-09-01

    High-aspect-ratio microstructures (HARMs) have a variety of potential applications in heat transfer, fluid mechanics, catalysts and other microelectromechanical systems (MEMS). The aim of this work is to demonstrate the feasibility to fabricate high performance particulate metal-matrix composite and intermetallic micromechanical structures using the LIGA process. Well-defined functionally graded Ni-Al2O3 and Ni-Al high-aspect-ratio microposts were electroformed into lithographically patterned PMMA holes from a nickel sulfamate bath containing submicron alumina and a diluted Watts bath containing microsized aluminum particles, respectively. SEM image analysis showed that the volume fraction of the alumina reached up to around 30% in the Ni-Al2O3 deposit. The Vickers microhardness of these composites is in the range of 418 through 545, which is higher than those of nickel microstructures from a similar particle-free bath and other Ni-based electrodeposits. In the work on Ni-Al electroplating, a newly developed diluted Watts bath was used to codeposit micron-sized aluminum particles. The intermetallic compound Ni3Al was formed by the reaction of nickel matrices and aluminum particles through subsequent annealing at 630 degrees Celsius. WDS and XRD analyses confirmed that the annealed coating is a two-phase (Ni-Ni3Al) composite. The maximum aluminum volume fraction reached 19% at a cathode current density of 12 mA cm-2, and the Vickers microhardness of the as-deposited coatings is in the range 392 - 515 depending on the amount of aluminum incorporated.

  11. TBK1 is associated with ALS and ALS-FTD in Sardinian patients.

    PubMed

    Borghero, Giuseppe; Pugliatti, Maura; Marrosu, Francesco; Marrosu, Maria Giovanna; Murru, Maria Rita; Floris, Gianluca; Cannas, Antonino; Occhineri, Patrizia; Cau, Tea B; Loi, Daniela; Ticca, Anna; Traccis, Sebastiano; Manera, Umberto; Canosa, Antonio; Moglia, Cristina; Calvo, Andrea; Barberis, Marco; Brunetti, Maura; Gibbs, J Raphael; Renton, Alan E; Errichiello, Edoardo; Zoledziewska, Magdalena; Mulas, Antonella; Qian, Yong; Din, Jun; Pliner, Hannah A; Traynor, Bryan J; Chiò, Adriano

    2016-07-01

    Recently, mutations in the TANK-binding kinase 1 (TBK1) gene were identified as a cause for amyotrophic lateral sclerosis (ALS) with or without comorbid frontotemporal dementia. We have assessed the frequency and clinical characteristics of TBK1 mutations in a cohort of ALS patients of Sardinian ancestry. Whole-exome sequencing was performed on Hiseq2000 platform (Illumina). Genome analysis Toolkit was used to align and to code variants according to Human Genome (UCSC hg19). Mutation was confirmed with Sanger sequence. In our screening of 186 Sardinian ALS cases, we found 3 (1.6%) patients carrying 3 distinct novel genetic variants: a nonsynonymous SNV c.1150C>T leading to a p.Arg384Thr change in exon 9; a nonsynonymous SNV c.1331G>A causes a p.Arg444Gln change in exon 11; and a frameshift deletion c.2070delG (p.Met690fs) at the exon 20 of the gene leading to a stop at 693 codon. The latter patients also carried missense mutation c.98C>T of the SQSTM1 gene causing a substitution of an arginine with a valine at the position 33 (p.Arg33Val). All variants were found to be deleterious according to in silico predictions. All cases were apparently sporadic and one of them showed frontotemporal dementia associated to ALS. These mutations were not found in 2 cohorts of 6780 ethnic-matched controls. We have found that TBK1 mutations account for 1.6% of Sardinian ALS cases. Our data support the notion that TBK1 is a novel ALS gene, providing important evidence complementary to the first descriptions. PMID:27156075

  12. Molar Volume Modeling of Ti-Al-Nb and Ti-Al-Mo Ternary Systems

    NASA Astrophysics Data System (ADS)

    Zhu, Jun; Zhang, Chuan; Cao, Weisheng; Chen, Shuanglin; Zhang, Fan; Park, Joon Sik; Yi, Seonghoon

    2015-08-01

    Molar volume modeling was performed for both Ti-Al-Nb and Ti-Al-Mo ternary systems based on the thermodynamic modeling of these two systems. Comparison between the calculated phase equilibria and the experimental data proved the accuracy of thermodynamic modeling. With the calculated density contour curves superimposed on the equilibrium phase diagram, it provides a map for alloy developers to identify the promising alloy compositions that satisfy both the phase stability and density requirements and rule out those that fail to meet the requirements.

  13. Pit initiation in AlO{sub x}/Al thin films

    SciTech Connect

    Son, K.A.; Barbour, J.C.; Missert, N.; Wall, F.D.; Copeland, R.G.; Martinez, M.A.; Minor, K.G.; Buchheit, R.G.; Isaacs, H.S.

    1998-12-31

    The electrochemical responses of AlO{sub x}/Al thin films have been investigated as a function of film growth conditions which produce films with different grain orientation, size and morphology. Films with smooth, 150 nm diameter, randomly oriented grains show a higher pitting potential and lower passive current than those films with large grain-boundary grooving from a mixture of smooth micron-sized, (200)-oriented grains and 300--500 nm diameter, (220)-oriented grains. These results suggest that surface roughness from grain-boundary grooving affects the pitting resistance more strongly than does the grain boundary density.

  14. Ac Impedance Spectroscopy Of Al/A-Sic/C-Si(P)/Al Heterostructure under Illumination

    NASA Astrophysics Data System (ADS)

    Perný, Milan; Šály, Vladimír; Váry, Michal; Mikolášek, Miroslav; Huran, Jozef; Packa, Juraj

    2014-05-01

    The amorphous silicon carbide/crystalline silicon heterojunction was prepared and analyzed. The current-voltage (I - V ) measurements showed the barrier properties of prepared sample. Biased impedance spectra of Al/a-SiC/c-Si(p)/Al heterojunction under the standard illumination are reported and analyzed. AC measurements in the illuminated conditions were processed in order to identify electronic behavior using equivalent AC circuit which was suggested and obtained by fitting the measured impedance data. A phenomenon of negative capacitance/resistance in certain frequency range has been observed.

  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. Diagnostic timelines and delays in diagnosing amyotrophic lateral sclerosis (ALS).

    PubMed

    Paganoni, Sabrina; Macklin, Eric A; Lee, Alexandra; Murphy, Alyssa; Chang, Judith; Zipf, Amanda; Cudkowicz, Merit; Atassi, Nazem

    2014-09-01

    The objective of this study was to characterize the diagnostic timelines and their predictors in people with amyotrophic lateral sclerosis (ALS). Patients were identified through ALS billing codes. Time from presenting symptom to first doctor visit, first doctor visit to suspected ALS diagnosis, suspected to confirmed ALS diagnosis, and presenting symptom to confirmed ALS diagnosis (total diagnostic time) were collected. Regression models were used to analyze the predictors of diagnostic delay. Three hundred and four ALS patients were included in the analysis. Median total diagnostic time was 11.5 months. Diagnostic timelines were longer in patients with age > 60 years (p < 0.001), sporadic ALS (p = 0.043), and limb onset (p = 0.010). The presence of fasciculations, slurred speech, and lower extremity weakness when symptoms were first noted were independent predictors of shorter time to ALS diagnosis (p = 0.04, p = 0.02, and p = 0.04, respectively). About half of the patients (52%) received an alternative diagnosis and each patient saw an average of three different physicians before ALS diagnosis was confirmed. In conclusion, diagnostic timelines in ALS are long, and patients see many physicians and receive multiple alternative diagnoses before the diagnosis of ALS is confirmed. Older age, sporadic disease, and limb onset can delay ALS diagnosis. PMID:24981792

  17. Motor neuron death in ALS – programmed by astrocytes?

    PubMed Central

    Pirooznia, Sheila K.; Dawson, Valina L.; Dawson, Ted M.

    2014-01-01

    Motor neurons in ALS die via cell-autonomous and non-cell autonomous mechanisms. Using adult human astrocytes and motor neurons, Re et al (2014) discover that familial and sporadic ALS derived human adult astrocytes secrete neurotoxic factors that selectively kill motor neurons through necroptosis, suggesting a new therapeutic avenue. PMID:24607221

  18. Excitation BolsTORs motor neurons in ALS mice.

    PubMed

    Mattson, Mark P

    2013-10-01

    It is unclear why motor neurons selectively degenerate in amyotrophic lateral sclerosis (ALS). Saxena et al. (2013) demonstrate that excitation of motor neurons can prevent their demise in a mouse model of inherited ALS by a mechanism involving the mTOR pathway. PMID:24094096

  19. 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.

  20. Influence of FeCrAl Content on Microstructure and Bonding Strength of Plasma-Sprayed FeCrAl/Al2O3 Coatings

    NASA Astrophysics Data System (ADS)

    Zhou, Liang; Luo, Fa; Zhou, Wancheng; Zhu, Dongmei

    2016-02-01

    Low-power plasma-sprayed FeCrAl/Al2O3 composite coatings with 1.5 mm thickness have been fabricated for radar absorption applications. The effects of FeCrAl content on the coating properties were studied. The FeCrAl presents in the form of a few thin lamellae and numerous particles, demonstrating relatively even distribution in all the coatings. Results show that the micro-hardness and porosity decrease with the increase in FeCrAl content. With FeCrAl content increasing from 28 to 47 wt.%, the bonding strength of the coatings with 1.5 mm thickness increases from 10.5 to 27 MPa, and the failure modes are composed of cohesive and adhesive failure, which are ascribed to the coating microstructure and the residual stress, respectively.

  1. Precipitation of Kr after implantation into Al

    SciTech Connect

    Birtcher, R.C.; Jaeger, W.

    1985-09-01

    Transmission electron microscopy (TEM) was used to perform a systematic study of the microstructural evolution in Al as a function of the fluence received during 65 keV Kr/sup +/ ion implantation at room temperature. At the lower fluences (2 x 10/sup 16/ to 2 x 10/sup 19/ Kr/sup +/m/sup -2/), isolated dislocation loops and the evolution of a dislocation network was observed by TEM. Above fluences of 10/sup 19/ Kr/sup +/m/sup -2/, the microstructure is dominated by a high density of Kr bubbles whose average size increases with dose. The appearance of additional electron diffraction reflections indicates that the majority of the bubbles contain solid fcc Kr that is epitaxially aligned with the fcc Al matrix. Above fluences of 2 x 10/sup 20/ Kr/sup +/m/sup -2/ an increasing fraction of the Kr is in a liquid or gas-like phase. The thermal stability of the microstructure, characteristic of the different fluence regimes, was investigated up to 640/sup 0/C by in situ TEM annealing experiments.

  2. 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.

  3. 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

    ...-Saudi Also Known as Ahmed Abdullah S al-Zahrani Also Known as Ahmad Abdullah Salih Al- Zahrani Also... Abdullah Saleh al-Khazmari, also known as Abu Maryam al-Saudi; also known as Ahmed Abdullah S...

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

    NASA Astrophysics Data System (ADS)

    Funato, Mitsuru; Banal, Ryan G.; Kawakami, Yoichi

    2015-11-01

    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.

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

    SciTech Connect

    Funato, Mitsuru 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.

  6. Supra-canonical 26Al/27Al and the residence time of CAIs in the solar protoplanetary disk.

    PubMed

    Young, Edward D; Simon, Justin I; Galy, Albert; Russell, Sara S; Tonui, Eric; Lovera, Oscar

    2005-04-01

    The canonical initial 26Al/27Al ratio of 4.5 x 10(-5) has been a fiducial marker for the beginning of the solar system. Laser ablation and whole-rock multiple-collector inductively coupled plasma-source mass spectrometry magnesium isotope analyses of calcium- and aluminum-rich inclusions (CAIs) from CV3 meteorites demonstrate that some CAIs had initial 26Al/27Al values at least 25% greater than canonical and that the canonical initial 26Al/27Al cannot mark the beginning of solar system formation. Using rates of Mg diffusion in minerals, we find that the canonical initial 26Al/27Al is instead the culmination of thousands of brief high-temperature events incurred by CAIs during a 10(5)-year residence time in the solar protoplanetary disk. PMID:15746387

  7. Interdiffusion and intrinsic diffusion in the NiAl /delta/ phase of the Al-Ni system

    NASA Technical Reports Server (NTRS)

    Shankar, S.; Seigle, L. L.

    1978-01-01

    Interdiffusion coefficients at 950 to 1150 C and the ratio of intrinsic diffusion coefficients at 1100 C were measured as functions of composition in the NiAl (delta) phase of the Al-Ni system, using a vapor-solid technique. Diffusivity values were also obtained for the Ni3Al (epsilon) and Ni (Al) solid solution (zeta) phases from 950 to 1150 C. The interdiffusion coefficient in NiAl (delta) varies several orders of magnitude over the delta phase field with a deep minimum in the diffusivity-composition curve at 48 to 49 at% Al. The ratio of intrinsic diffusion coefficients DNi/DAl, in the delta phase also varies with composition from a value of 3 to 3.5 below 50 at% Al to 0.1 or less above 50 at% Al.

  8. 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.

  9. 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.

  10. Role of Tricoordinate Al Sites in CH3ReO3/Al2O3 Olefin Metathesis Catalysts.

    PubMed

    Valla, Maxence; Wischert, Raphael; Comas-Vives, Aleix; Conley, Matthew P; Verel, René; Copéret, Christophe; Sautet, Philippe

    2016-06-01

    Re2O7 supported on γ-alumina is an alkene metathesis catalyst active at room temperature, compatible with functional groups, but the exact structures of the active sites are unknown. Using CH3ReO3/Al2O3 as a model for Re2O7/Al2O3, we show through a combination of reactivity studies, in situ solid-state NMR, and an extensive series of DFT calculations, that μ-methylene structures (Al-CH2-ReO3-Al) containing a Re═O bound to a tricoordinated Al (AlIII) and CH2 bound to a four-coordinated Al (AlIVb) are the precursors of the most active sites for olefin metathesis. The resting state of CH3ReO3/Al2O3 is a distribution of μ-methylene species formed by the activation of the C-H bond of CH3ReO3 on different surface Al-O sites. In situ reaction with ethylene results in the formation of Re metallacycle intermediates, which were studied in detail through a combination of solid-state NMR experiments, using labeled ethylene, and DFT calculations. In particular, we were able to distinguish between metallacycles in TBP (trigonal-bipyramidal) and SP (square-pyramidal) geometry, the latter being inactive and detrimental to catalytic activity. The SP sites are more likely to be formed on other Al sites (AlIVa/AlIVa). Experimentally, the activity of CH3ReO3/Al2O3 depends on the activation temperature of alumina; catalysts activated at or above 500 °C contain more active sites than those activated at 300 °C. We show that the dependence of catalytic activity on the Al2O3 activation temperature is related to the quantity of available AlIII-defect sites and adsorbed H2O. PMID:27140286

  11. Arsenic entrapment by nanocrystals of Al-magnetite: The role of Al in crystal growth and As retention.

    PubMed

    Freitas, Erico T F; Stroppa, Daniel G; Montoro, Luciano A; de Mello, Jaime W V; Gasparon, Massimo; Ciminelli, Virginia S T

    2016-09-01

    The nature of As-Al-Fe co-precipitates aged for 120 days are investigated in detail by High Resolution Transmission Electron Microscopy (HRTEM), Scanning TEM (STEM), electron diffraction, Energy Dispersive X-Ray Spectroscopy (EDS), Electron Energy-Loss Spectroscopy (EELS), and Energy Filtered Transmission Electron Microscopy (EFTEM). The Al present in magnetite is shown to favour As incorporation (up to 1.10 wt%) relative to Al-free magnetite and Al-goethite, but As uptake by Al-magnetite decreases with increasing Al substitution (3.53-11.37 mol% Al). Arsenic-bearing magnetite and goethite mesocrystals (MCs) are formed by oriented aggregation (OA) of primary nanoparticles (NPs). Well-crystalline magnetite likely formed by Otswald ripening was predominant in the Al-free system. The As content in Al-goethite MCs (having approximately 13% substituted Al) was close to the EDS detection limit (0.1 wt% As), but was below detection in Al-goethites with 23.00-32.19 mol% Al. Our results show for the first time the capacity of Al-magnetite to incorporate more As than Al-free magnetite, and the role of Al in favouring OA-based crystal growth under the experimental conditions, and therefore As retention in the formed MCs. The proposed mechanism of As incorporation involves adsorption of As onto the newly formed NPs. Arsenic is then trapped in the MCs as they grow by self-assembly OA upon attachment of the NPs. We conclude that Al may diffuse to the crystal faces with high surface energy to reduce the total energy of the system during the attachment events, thus favouring the oriented aggregation. PMID:27258899

  12. Mutations in UBQLN2 cause dominant X-linked juvenile and adult-onset ALS and ALS/dementia.

    PubMed

    Deng, Han-Xiang; Chen, Wenjie; Hong, Seong-Tshool; Boycott, Kym M; Gorrie, George H; Siddique, Nailah; Yang, Yi; Fecto, Faisal; Shi, Yong; Zhai, Hong; Jiang, Hujun; Hirano, Makito; Rampersaud, Evadnie; Jansen, Gerard H; Donkervoort, Sandra; Bigio, Eileen H; Brooks, Benjamin R; Ajroud, Kaouther; Sufit, Robert L; Haines, Jonathan L; Mugnaini, Enrico; Pericak-Vance, Margaret A; Siddique, Teepu

    2011-09-01

    Amyotrophic lateral sclerosis (ALS) is a paralytic and usually fatal disorder caused by motor-neuron degeneration in the brain and spinal cord. Most cases of ALS are sporadic but about 5-10% are familial. Mutations in superoxide dismutase 1 (SOD1), TAR DNA-binding protein (TARDBP, also known as TDP43) and fused in sarcoma (FUS, also known as translocated in liposarcoma (TLS)) account for approximately 30% of classic familial ALS. Mutations in several other genes have also been reported as rare causes of ALS or ALS-like syndromes. The causes of the remaining cases of familial ALS and of the vast majority of sporadic ALS are unknown. Despite extensive studies of previously identified ALS-causing genes, the pathogenic mechanism underlying motor-neuron degeneration in ALS remains largely obscure. Dementia, usually of the frontotemporal lobar type, may occur in some ALS cases. It is unclear whether ALS and dementia share common aetiology and pathogenesis in ALS/dementia. Here we show that mutations in UBQLN2, which encodes the ubiquitin-like protein ubiquilin 2, cause dominantly inherited, chromosome-X-linked ALS and ALS/dementia. We describe novel ubiquilin 2 pathology in the spinal cords of ALS cases and in the brains of ALS/dementia cases with or without UBQLN2 mutations. Ubiquilin 2 is a member of the ubiquilin family, which regulates the degradation of ubiquitinated proteins. Functional analysis showed that mutations in UBQLN2 lead to an impairment of protein degradation. Therefore, our findings link abnormalities in ubiquilin 2 to defects in the protein degradation pathway, abnormal protein aggregation and neurodegeneration, indicating a common pathogenic mechanism that can be exploited for therapeutic intervention. PMID:21857683

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

    PubMed

    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

  15. Adhesion strength and nucleation thermodynamics of four metals (Al, Cu, Ti, Zr) on AlN substrates

    NASA Astrophysics Data System (ADS)

    Tao, Yuan; Ke, Genshui; Xie, Yan; Chen, Yigang; Shi, Siqi; Guo, Haibo

    2015-12-01

    Devices based on AlN generally require adherent and strong interfaces between AlN and other materials, whereas most metals are known to be nonwetting to AlN and form relatively weak interfaces with AlN. In this study, we selected four representative metals (Al, Cu, Ti, and Zr) to study the adhesion strength of the AlN/metal interfaces. Mathematical models were constructed between the adhesion strength and enthalpy of formation of Al-metal solid solutions, the surface energies of the metals, and the lattice mismatch between the metals and AlN, based on thermodynamic parameters calculated using density functional theory. It appears that the adhesion strength is mainly determined by the lattice mismatch, and is in no linear correlation with either the Al-metal solution's formation enthalpies or the metals' surface energies. We also investigated the nucleation thermodynamics of the four metals on AlN substrates. It was found that Ti forms the strongest interface with AlN, and has the largest driving force for nucleation on AlN substrates among the four metals.

  16. Al-Si-Cu/TiN multilayer interconnection and Al-Ge reflow sputtering technologies for quarter-micron devices

    NASA Astrophysics Data System (ADS)

    Kikkawa, Takamaro; Kikuta, Kuniko

    1993-05-01

    Issues of interconnection technologies for quarter-micron devices are the reliability of metal lines with quarter-micron feature sizes and the formation of contact-hole-plugs with high aspect ratios. This paper describes a TiN/Al-Si-Cu/TiN/Al-Si-Cu/TiN/Ti multilayer conductor structure as a quarter-micron interconnection technology and aluminum-germanium (Al-Ge) reflow sputtering as a contact-hole filling technology. The TiN/Al-Si-Cu/TiN/Al-Si-Cu/TiN/Ti multilayer conductor structure could suppress stress-induced voiding and improve the electromigration mean-time to failure. These improvements are attributed to the fact that the grain boundaries for the Al-Si-Cu film and the interfaces between the Al-Si-Cu and the TiN films are strengthened by the rigid intermetallic compound, TiAl3. The Al-Ge alloy reflow sputtering is a candidate for contact- and via-hole filling technologies in terms of reducing fabrication costs. The Al-Ge reflow sputtering achieved low temperature contact hole filling at 300 degree(s)C. Contact holes with a diameter of 0.25 micrometers and aspect ratio of 4 could be filled. This is attributed to the low eutectic temperature for Al-Ge (424 degree(s)C) and the effect of thin polysilicon underlayer on the enhancement of Al-Ge reflow.

  17. Catalytic effect of Al and AlN interlayer on the growth and properties of containing carbon films

    NASA Astrophysics Data System (ADS)

    Zhou, Bing; Liu, Zhubo; Tang, Bin; Rogachev, A. V.

    2015-01-01

    Diamond-like carbon (DLC) and carbon nitride (CNx) bilayer films with Al and AlN interlayer were fabricated by pulse cathode arc technique. The structure, composition, morphology and mechanical properties of the films were investigated by Raman, Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Knoop sclerometer and surface profilometer. The results indicated that the complete diffusion between C and Al atoms occurs in the Al/DLC and Al/CNx bilayer. Al interlayer induces the increase of the size and ordering of Csp2 clusters in the films but AlN interlayer increases the disordering degree of Csp2 clusters. XPS results showed that a higher content of Csp3/Csp2 bonds presents in the Al/CNx bilayer, and Al and AlN interlayer decreases the atomic ratio of N/C. AFM with phase contrast mode illustrated the morphologic characteristics of the bilayer films. All the bilayers show a nano-structural surface. The morphology changes of the bilayer were well explained by the surface state of the substrate and the growth mechanism of DLC films. The hardness of Al/DLC bilayer decreases but it increases for the other bilayers compared to the corresponding DLC (CNx) monolayer. The internal stress of the bilayer is significantly lower than that of the monolayer except for the AlN/CNx bilayer. These studies could make the difference at the time of choosing a suitable functional film for certain application.

  18. Enhancing phosphate adsorption by Mg/Al layered double hydroxide functionalized biochar with different Mg/Al ratios.

    PubMed

    Li, Ronghua; Wang, Jim J; Zhou, Baoyue; Awasthi, Mukesh Kumar; Ali, Amjad; Zhang, Zengqiang; Gaston, Lewis A; Lahori, Altaf Hussain; Mahar, Amanullah

    2016-07-15

    Mg/Al ratio plays a significant role for anion adsorption by Mg/Al-layered double hydroxides (Mg/Al-LDHs) modified biochar. In this study, Mg/Al-LDHs biochar with different Mg/Al ratios (2, 3, 4) were prepared by co-precipitation for phosphate removal from aqueous solution. Factors on phosphate adsorption including Mg/Al ratio, pH, and the presence of other inorganic anions were investigated through batch experiments. Increasing Mg/Al ratio in the Mg/Al-LDHs biochar composites generally enhanced phosphate adsorption with Langmuir adsorption maximum calculated at 81.83mg phosphorous (P) per gram of 4:1Mg/Al-LDHs biochar at pH3.0. The adsorption process was best described by the pseudo-second-order kinetic model. Solution pH had greater effects on the phosphate adsorption by Mg/Al LDHs biochar composites with lower Mg/Al ratios. The presence of other inorganic anions decreased the phosphate adsorption efficiency in the order of F(-) > SO4(2-) > NO2(-) >Cl(-). Phosphate adsorption mechanism involves ion exchange, electrostatic attraction and surface inner-sphere complex formation. Overall, Mg/Al-LDHs biochar composites offer a potential alternative of carbon-based adsorbent for phosphate removal from aqueous solution. PMID:27058131

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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.

  20. Investigation of locally favored structures in Al-La-Ni metallic glasses using ^27Al NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sandor, Magdalena; Xi, Xuekui; Wu, Yue

    2008-10-01

    Al-TM-RE (TM= transition metal, RE = rare earth) bulk metallic glasses (BMGs) with high Al content have gained much research interest due to their high potential as structural and functional materials. The first recent fabrication of La85-xAlxNi15 (15 <= x <= 70) BMGs have inspired an NMR systematic study of their locally favored structures (LFSs). These BMGs are reported to show characteristics of high thermal stability, fragility, and considerable mechanical strength. ^27Al NMR spectroscopy and nutation experiments are performed to unveil the sensitive structural dependence on line width and quadrupolar frequency with Al composition. It is observed that maximum glass forming ability (GFA) for this system prefers a decrease of symmetry at Al sites. Minimal GFA corresponding to instances of high symmetry occur in Al-rich and Al-poor regimes. These results, in addition to previous work, suggest that Ni and La atoms have unique local chemical and topological environments at different Al compositions. The monotonic decrease of relatively small ^27Al Knight shifts with increasing Al concentration demonstrates the evolution of local electronic structure at Al sites. This study is valuable in correlating the unique role that TM and RE elements play in local compositional and geometrical order of high glass-forming Al-based BMGs.

  1. Room temperature luminescence and ferromagnetism of AlN:Fe

    NASA Astrophysics Data System (ADS)

    Li, H.; Cai, G. M.; Wang, W. J.

    2016-06-01

    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 Fe2+ 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.

  2. Diffusion Research in BCC Ti-Al-Mo Ternary Alloys

    NASA Astrophysics Data System (ADS)

    Chen, Yi; Tang, Bin; Xu, Guanglong; Wang, Chuanyun; Kou, Hongchao; Li, Jinshan; Cui, Yuwen

    2014-04-01

    Interdiffusion in Ti-Al-Mo β solid solution was investigated at 1523 K (1250 °C) by analyzing diffusion couples. From the concentration profiles analytically represented by error function expansion (ERFEX), the ternary interdiffusion coefficients and impurity diffusivity were extracted by the Whittle-Green and generalized Hall methods. A comparison of the diffusion in five Ti-Al-X (Co, Cr, Fe, Mo, and V) ternaries reveals Ti-Al-Mo is comparably like Ti-Al-(Cr, V) while Ti-Al-(Co, Fe) are predominantly of interstitial nature.

  3. Probing Galactic 26Al with Exotic Ion Beams

    NASA Astrophysics Data System (ADS)

    Chen, Alan A.

    2006-07-01

    The goal of understanding the production of galactic 26Al brings together progress in nuclear astrophysics from observations, theory, meteoritics, and laboratory experiments. In the case of experimental work, nuclear reactions involving unstable isotopes are being studied to elucidate the production of 26Al in stellar explosive nucleosynthesis. We discuss a direct measurement of the 26Al(p,γ)27Si reaction with the DRAGON collaboration at TRIUMF, and a measurement of 25Al+p elastic scattering with the CRIB (CNS-U.Tokyo) collaboration, toward constraining the 25Al(p,γ)26Si reaction.

  4. Strong adsorption of Al-doped carbon nanotubes toward cisplatin

    NASA Astrophysics Data System (ADS)

    Li, Wei; Li, Guo-Qing; Lu, Xiao-Min; Ma, Juan-Juan; Zeng, Peng-Yu; He, Qin-Yu; Wang, Yin-Zhen

    2016-08-01

    The adsorption of cisplatin molecule on Al-doped CNTs is investigated using density functional theory. The obtained results indicate that Al-doped carbon nanotubes can strongly absorb cisplatin. After absorbing cisplatin, the symmetry of CNTs has some changes. We innovatively defined a parameter of symmetry variation which relates to the adsorption. By analyzing the electronic structure, it can be concluded that under the circumstance that cisplatin was absorbed by Al-doped CNTs through aluminum atom of Al-doped CNTs. In conclusion, Al-doped CNTs is a kind of potential delivery carrier with high quality for anticancer drug cisplatin.

  5. Creep in Directionally Solidified NiAl-Mo Eutectics

    SciTech Connect

    Dudova, Marie; Kucharova, Kveta; Bartak, Tomas; Bei, Hongbin; George, Easo P; Somsen, Ch.; Dlouhy, A.

    2011-01-01

    A directionally solidified NiAl-Mo eutectic and an NiAl intermetallic, having respective nominal compositions Ni-45.5Al-9Mo and Ni-45.2Al (at.%), were loaded in compression at 1073 and 1173 K. Formidable strengthening by regularly distributed Mo fibres (average diameter 600 nm, volume fraction 14%) was observed. The fibres can support compression stresses transferred from the plastically deforming matrix up to a critical stress of the order of 2.5 GPa, at which point they yield. Microstructural evidence is provided for the dislocation-mediated stress transfer from the NiAl to the Mo phase.

  6. Thermal- and electromigration-induced stresses in passivated Al- and AlSiCu-interconnects

    SciTech Connect

    Beckers, D.; Schroeder, H.; Schilling, W.; Eppler, I.

    1997-05-01

    Mechanical stresses in microelectronic devices are of special interest because of degradation effects in microelectronic circuits such as stress induced voiding or electromigration. Al and al-alloys are commonly used as interconnect materials in integrated electronic devices. Stress induced voiding and degradation of metal lines by electromigration are closely related to the stresses in the lines. The authors have studied the strain and stress evolution during thermal cycling, isothermal relaxation and due to electromigration in passivated Al and AlSi(1%)Cu(0.5%) lines by X-Ray diffraction with variation of experimental parameters such as the aspect ratio and the electrical current density. Furthermore the extent of voiding and plastic shear deformation has been determined from the experimental metal strains with the help of finite element calculations. Main results are: (1) During thermal cycling the voiding is less than 2 {center_dot} 10{sup {minus}3}. The extent of plastic shear deformation increases with increasing line width and with decreasing flowstress. (2) During isothermal relaxation void growth occurs but no significant change in the plastic shear deformation. (3) An electric current in the lines causes no measurable additional change of the volume averaged stresses up to line failure.

  7. Phase correlations in the CuAlSe2-CuAlTe2 system

    NASA Astrophysics Data System (ADS)

    Korzun, B. V.; Fadzeyeva, A. A.; Bente, K.; Schmitz, W.; Kommichau, G.

    2005-07-01

    Alloys in the CuAlSe2-CuAlTe2 system were synthesized in BN-crucibles in silica tubes under vacuum to obtain the corresponding phase equilibria. X-ray powder diffraction and thermal analytic data of the T-x phase diagram revealed a complete solid solutions series in the subsolidus region. Within the CuAlSe2xTe2(1-x) system the refined lattice parameters a and c approximately obey the Vegard rule and also the cell volume and the heat of fusion confirm linear correlations with the composition of the mixed crystals. The anion position parameter calculated after S. C. Abrahams & J. L. Bernstein (uAB) and J. E Jaffe & A. Zunger (uJZ) is greater than 0.25 and reveals a linear dependence on composition. The liquidus part of the CuAlSe2xTe2(1-x) system with x < 0.35 exhibits vertical section behaviour with a ternary peritectic followed up by a ternary monotectic whereas the region with x > 0.35 shows quasibinary equilibria.

  8. Electronic transport through Al/InN nanowire/Al junctions

    DOE PAGESBeta

    Lu, Tzu -Ming; Wang, George T.; Pan, Wei; Zhao, S.; Mi, Z.

    2016-02-01

    We report non-linear electronic transport measurement of Al/Si-doped n-type InN nanowire/Al junctions performed at T = 0.3 K, below the superconducting transition temperature of the Al electrodes. The proximity effect is observed in these devices through a strong dip in resistance at zero bias. In addition to the resistance dip at zero bias, several resistance peaks can be identified at bias voltages above the superconducting gap of the electrodes, while no resistance dip is observed at the superconducting gap. The resistance peaks disappear as the Al electrodes turn normal beyond the critical magnetic field except one which remains visible atmore » fields several times higher than critical magnetic field. An unexpected non-monotonic magnetic field dependence of the peak position is observed. As a result, we discuss the physical origin of these observations and propose that the resistance peaks could be the McMillan-Rowell oscillations arising from different closed paths localized near different regions of the junctions.« less

  9. 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…

  10. Enhanced TC in granular and thin film Al-Al2O3 nanostructures

    NASA Astrophysics Data System (ADS)

    Higgins, J. S.; Greene, R. L.

    It is known since the 1970s that the superconducting transition temperature of granular aluminum films can be as high as two to three times the transition temperature of bulk aluminum, depending on the grain size and how strongly the nanometer size grains are connected1,2. As the strength of the grain connectivity becomes increasingly weak, the enhanced TC is suppressed. The mechanism behind this enhancement is still under debate. Recently, work on larger aluminum nanoparticles (18nm) embedded in an insulating Al2O3 matrix showed an onset of the superconducting transition as high as three times that of bulk aluminum3. In this situation, the Al grains are electrically disconnected and in a regime far removed from that of the granular films. Here we compare the two situations through electronic and thermal measurements in order to help elucidate the mechanism behind the enhancements. 1S. Pracht, et al., arXiv:1508.04270v1 [cond-mat.supr-con] (2015). 2G. Deutscher, New Superconductors From Granular to High TC, New Jersey: World Scientific, 2006, p. 72-74. 3V. N. Smolyaninova, et al., Sci. Rep. 5, 15777 (2015). Funding by NSF DMR # 1410665.

  11. Enhanced fibroblast cell adhesion on Al/Al2O3 nanowires

    NASA Astrophysics Data System (ADS)

    Aktas, O. C.; Sander, M.; Miró, M. M.; Lee, J.; Akkan, C. K.; Smail, H.; Ott, A.; Veith, M.

    2011-02-01

    Biological cells stick together via transmembrane proteins, which are linked to receptor molecules of the extracellular matrix (ECM). This specific biochemical adhesion plays a leading role in many cellular processes, among them cell differentiation, morphogenesis, and wound healing. Various medical applications require endogen cells to bind to an exogene substrate as in the case of an implant. Coatings with proteins that naturally belong to the ECM are known to enhance the cell adhesion. However, the choice of inorganic materials, which promote cell adhesion, is limited. Here, we report on a new engineered surface composed of Al/Al2O3 bi-phasic nanowires (NWs), which promotes the adhesion of fibroblast cells. Fibroblasts grow well on this inorganic layer and keep proliferating. Using the cell monolayer rheology (CMR) technique, we show that the adhesion of fibroblasts on Al/Al2O3 NWs is comparable to fibronectin coated surfaces. To our knowledge, this is one of the strongest cell adhesions on an inorganic surface, which has been reported on so far, since it compares to bio-organic layers such as fibronectin.

  12. Constitutive Model Constants for Al7075-T651 and Al7075-T6

    NASA Astrophysics Data System (ADS)

    Brar, Nachhatter; Joshi, Vasant; Harris, Bryan

    2009-06-01

    Aluminum 7075-T651 and 7075-T6 are characterized at quasi-static and high strain rates to determine Johnson-Cook (J-C) strength and fracture model constants. Constitutive model constants are required as input to computer codes to simulate projectile (fragment) impact or similar impact events on structural components made of these material. J-C strength model constants (A, B, n, C, and m) for the two alloys are determined from tension stress-strain data at room and high temperature to 250^oC. J-C strength model constants for Al7075-T651 are: A=527 MPa, B=676 MPa, n=0.71, C=0.017, and m=1.61 and for Al7075-T6: A = 546 MPa, B = 674 MPa, n = 0.72, C = 0.059, and m =1.56. J-C fracture model constants are determined form quasi-static and high strain rate/high temperature tests on notched and smooth tension specimens. J-C fracture model constants for the two alloys are: Al7075-T651; D1 = 0.110, D2 = 0.573, D3= -3.4446, D4 = 0.016, and D 5= 1.099 and Al7075-T6; D1= 0.451 D2= -0.952 D3= -.068, D4 =0.036, and D5 = 0.697.

  13. X-Ray Videomicroscopy Studies of Eutectic Al-Si Solidification in Al-Si-Cu

    NASA Astrophysics Data System (ADS)

    Mathiesen, R. H.; Arnberg, L.; Li, Y.; Meier, V.; Schaffer, P. L.; Snigireva, I.; Snigirev, A.; Dahle, A. K.

    2011-01-01

    Al-Si eutectic growth has been studied in-situ for the first time using X-ray video microscopy during directional solidification (DS) in unmodified and Sr-modified Al-Si-Cu alloys. In the unmodified alloys, Si is found to grow predominantly with needle-like tip morphologies, leading a highly irregular progressing eutectic interface with subsequent nucleation and growth of Al from the Si surfaces. In the Sr-modified alloys, the eutectic reaction is strongly suppressed, occurring with low nucleation frequency at undercoolings in the range 10 K to 18 K. In order to transport Cu rejected at the eutectic front back into the melt, the modified eutectic colonies attain meso-scale interface perturbations that eventually evolve into equiaxed composite-structure cells. The eutectic front also attains short-range microscale interface perturbations consistent with the characteristics of a fibrous Si growth. Evidence was found in support of Si nucleation occurring on potent particles suspended in the melt. Yet, both with Sr-modified and unmodified alloys, Si precipitation alone was not sufficient to facilitate the eutectic reaction, which apparently required additional undercooling for Al to form at the Si-particle interfaces.

  14. 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.

  15. 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.

  16. Magnetization anomaly of Nb3Al strands and instability of Nb3Al Rutherford cables

    SciTech Connect

    Yamada, Ryuji; Kikuchi, Akihiro; Wake, Masayoshi; /KEK, Tsukuba

    2006-08-01

    Using a Cu stabilized Nb{sub 3}Al strand with Nb matrix, a 30 meter long Nb{sub 3}Al Rutherford cable was made by a collaboration of Fermilab and NIMS. Recently the strand and cable were tested. In both cases instability was observed at around 1.5 Tesla. The magnetization of this Nb{sub 3}Al strand was measured first using a balanced coil magnetometer at 4.2 K. Strands showed an anomalously large magnetization behavior around at 1.6 T, which is much higher than the usual B{sub c2} {approx} 0.5 Tesla (4.2 K) of Nb matrix. This result is compared with the magnetization data of short strand samples using a SQUID magnetometer, in which a flux-jump signal was observed at 0.5 Tesla, but not at higher field. As a possible explanation for this magnetization anomaly, the interfilament coupling through the thin Nb films in the strands is suggested. The instability problem observed in low field tests of the Nb{sub 3}Al Rutherford cables is attributed to this effect.

  17. In situ investigation of spinodal decomposition in hypermonotectic Al Bi and Al Bi Zn alloys

    NASA Astrophysics Data System (ADS)

    Schaffer, P. L.; Mathiesen, R. H.; Arnberg, L.; Di Sabatino, M.; Snigirev, A.

    2008-05-01

    Spinodal decomposition of hypermonotectic Al-6 wt.%Bi, Al-8 wt.%Bi and Al-6 wt.%Bi-8 wt.%Zn alloys has been investigated using synchrotron radiography. In the case of the 6 and 8 wt.%Bi binary alloys undercoolings of 70 and 110 K, respectively, were required to initiate the L→L1+L2 reaction, which appeared to occur very close to the monotectic reaction temperature. The nucleated L2 droplets were set in collective size-dependent motion by forces coupled to external fields (gravity and imposed temperature gradient) as well as forces arising due to internal fluctuations of the system. With experimental conditions similar to those realized during strip casting of the same materials, it was found that the size-dependant droplet velocity field combined with Stokes drag at the L1-L2 interfaces as well as attractive and repulsive diffusion-coupling between adjacent L2 droplets, yield complex meso- to microscale hydrodynamics. The hydrodynamics are the dominating mechanisms for L2 droplet coagulation, and are accordingly decisive for the final size distribution and geometrical dispersion of the soft Bi-rich component in the cast material. A different decomposition mode was observed in the Al-6 wt.%Bi-8 wt.%Zn ternary alloy, with the L2 droplets undergoing an immiscible-miscible-immiscible transition. In contrast to what was found for the binaries, L2 domains formed at relatively small undercoolings, and very little droplet motion was observed, as all L2 domains nucleated and remained on the crucible walls until they encroached on the monotectic front. At small distances from the monotectic front a Zn-rich solute boundary layer preceding the α-Al, caused the L2 domains to dissolve as Bi-Zn-Al regains complete miscibility upon reaching a critical Zn-concentration. In the shallow mush region behind the monotectic reaction, a high Zn solid solubility and a relatively fast diffusion of Zn in α-Al combine to cause a rapid diminishing Zn concentration in the mush liquid

  18. The immiscibility of InAlN ternary alloy.

    PubMed

    Zhao, Guijuan; Xu, Xiaoqing; Li, Huijie; Wei, Hongyuan; Han, Dongyue; Ji, Zesheng; Meng, Yulin; Wang, Lianshan; Yang, Shaoyan

    2016-01-01

    We have used two models based on the valence force field and the regular solution model to study the immiscibility of InAlN ternary alloy, and have got the spinodal and binodal curves of InAlN. Analyzing the spinodal decomposition curves, we obtain the appropriate concentration region for the epitaxial growth of the InN-AlN pseudobinary alloy. At a temperature most common for the epitaxial growth of InAlN (1000 K), the solubility of InN is about 10%. Then we introduce the mismatch strain item into the Gibbs free energy, and the effect of different substrates is taken into consideration. Considering Si, Al2O3, InN, GaN, AlN as a substrate respectively, it is found that all the five systems are stabilized with the upper critical solution temperature largely reduced. Finally, InN and GaN are potential substrates for In-rich InAlN, while AlN and GaN substrates are recommended in the Al-rich region. Si and Al2O3 may be ideal substrates for thin InAlN film. PMID:27221345

  19. First Principles Study of Al-Li Intermetallic Compounds

    NASA Astrophysics Data System (ADS)

    Yu, Hai-li; Duan, Xiao-hui; Ma, Yong-jun; Zeng, Min

    2012-12-01

    The structural properties, heats of formation, elastic properties, and electronic structures of four compositions of binary Al-Li intermetallics, Al3Li, AlLi, Al2Li3, and Al4Li9, are analyzed in detail by using density functional theory. The calculated formation heats indicate a strong chemical interaction between Al and Li for all the Al-Li intermetallics. In particular, in the Li-rich Al-Li compounds, the thermodynamic stability of intermetallics linearly decreases with increasing concentration of Li. According to the computational single crystal elastic constants, all the four Al-Li intermetallic compounds considered here are mechanically stable. The polycrystalline elastic modulus and Poisson's ratio have been deduced by using Voigt, Reuss, and Hill approximations, and the calculated ratios of bulk modulus to shear modulus indicate that the four compositions of binary Al-Li intermetallics are brittle materials. With the increase of Li concentration, the bulk modulus of Al-Li intermetallics decreases in a linear manner.

  20. The immiscibility of InAlN ternary alloy

    PubMed Central

    Zhao, Guijuan; Xu, Xiaoqing; Li, Huijie; Wei, Hongyuan; Han, Dongyue; Ji, Zesheng; Meng, Yulin; Wang, Lianshan; Yang, Shaoyan

    2016-01-01

    We have used two models based on the valence force field and the regular solution model to study the immiscibility of InAlN ternary alloy, and have got the spinodal and binodal curves of InAlN. Analyzing the spinodal decomposition curves, we obtain the appropriate concentration region for the epitaxial growth of the InN-AlN pseudobinary alloy. At a temperature most common for the epitaxial growth of InAlN (1000 K), the solubility of InN is about 10%. Then we introduce the mismatch strain item into the Gibbs free energy, and the effect of different substrates is taken into consideration. Considering Si, Al2O3, InN, GaN, AlN as a substrate respectively, it is found that all the five systems are stabilized with the upper critical solution temperature largely reduced. Finally, InN and GaN are potential substrates for In-rich InAlN, while AlN and GaN substrates are recommended in the Al-rich region. Si and Al2O3 may be ideal substrates for thin InAlN film. PMID:27221345