Science.gov

Sample records for additional theoretical work

  1. M dwarfs: Theoretical work

    NASA Technical Reports Server (NTRS)

    Mullan, Dermott J.

    1987-01-01

    Theoretical work on the atmospheres of M dwarfs has progressed along lines parallel to those followed in the study of other classes of stars. Such models have become increasingly sophisticated as improvements in opacities, in the equation of state, and in the treatment of convection were incorporated during the last 15 to 20 years. As a result, spectrophotometric data on M dwarfs can now be fitted rather well by current models. The various attempts at modeling M dwarf photospheres in purely thermal terms are summarized. Some extensions of these models to include the effects of microturbulence and magnetic inhomogeneities are presented.

  2. Theoretical and experimental investigation of additive drag

    NASA Technical Reports Server (NTRS)

    Sibulkin, Merwin

    1954-01-01

    The significance of additive drag is discussed and equations for determining its approximate value are derived for annular and open-nose inlets. Charts are presented giving values of additive drag coefficient over a range of free-stream Mach numbers for open and for annular-nose inlets with conical flow at the inlet. The effects on additive drag of variable inlet-total-pressure recovery and static pressures on the centerbody are investigated and an analytical method of predicting the variation of pressure on the centerbody with mass-flow ratio is given. Experimental additive-drag values are presented for a series of 20 degree and 25 degree cone half-angle inlets and one open-nose inlet operating at free-stream Mach numbers of 1.8 and 1.6. A comparison with the theoretical values of additive drag shows excellent agreement for the open-nose inlet and moderately good agreement for the annular inlets. (author)

  3. Theoretical determination of cesiated work functions

    NASA Technical Reports Server (NTRS)

    Szejn, R. M.

    1972-01-01

    A computer program based on the theoretical work of Gyftopoulos, Steiner, and Levine on bimetallic systems and using a modified version of Wilkins' SIMCON subroutine SURFAS was written for the Univac 1108. This program, WFGSL, accepts the operating conditions and the physical parameters pertinent to the substrate and adsorbate, and outputs the field-free work function, electron current (Richardson equation), ion current (Saha equation), and fractional substrate coverage by the adsorbate. A brief description of the theory is presented together with a program description and listing. An application of the program to a bimetallic system of cesium (adsorbate) and rhenium (substrate) is also described.

  4. Working Memory and Children's Mental Addition.

    ERIC Educational Resources Information Center

    Adams, John W.; Hitch, Graham J.

    1997-01-01

    Two experiments investigated extent to which English- and German-speaking childrens' mental arithmetic was constrained by working memory. Found higher mental addition spans when numbers were visible throughout calculation than when not. Variation in addition span with age and arithmetical operation difficulty approximated to a linear function of…

  5. Work Scheduling and Family Interaction: A Theoretical Perspective.

    ERIC Educational Resources Information Center

    Gramling, Robert; Forsyth, Craig

    1987-01-01

    Offers an expansion of the construction-of-reality paradigm as proposed by Berger and Kellner (1964) as an appropriate theoretical perspective for the examination of the link between work scheduling and family interaction. Argues that this perspective is applicable across the family life cycle, and with increasingly evident nontraditional family…

  6. Historical and Theoretical Development of Culturally Competent Social Work Practice

    ERIC Educational Resources Information Center

    Kohli, Hermeet K.; Huber, Ruth; Faul, Anna C.

    2010-01-01

    This article provides a detailed review of the historical and theoretical context in which culturally competent practice has evolved in the social work profession and enables educators and practitioners to see holistic connections between the past and present. Historical review of the inclusion of diversity content is followed by definitions of…

  7. [ORGANIZATIONAL COMMITMENT AND WORK ENGAGEMENT - THEORETICAL CONCEPTIONS AND TERMINOLOGICAL PROBLEMS].

    PubMed

    Łaguna, Mariola; Mielniczuk, Emilia; Żaliński, Adam; Wałachowska, Karolina

    2015-01-01

    Engagement in professional activities and positive attitudes towards an organization are of significant importance to functioning and health of employees. Studies analysing the phenomena of employees' engagement and their relations with an organization undergo a dynamic development in both international and Polish research. Two theoretical conceptions: organizational commitment (by Meyer and Allen) and work engagement (by Schaufeli and Bakker) have become prominent in the field. They capture 2 similar, albeit distinct constructs. In English-language journals academics concentrate on theoretical and empirical analyses of similarities and differences between the 2 concepts, while in Polish publications scholars also have to deal with the issue of the original term translation. The problem lies mostly in Polish nomenclature of the dimensions proposed in both of these conceptions. Lack of common translations for different studies may cause confusion in this area of research. In the paper authors present a review of Polish translations of terms used in the discussed conceptions and a linguistic analysis of terms, both in English and in Polish. Authors provide solutions which could help to clarify terminology in Polish-language publications concerning organizational commitment and work engagement. This allows for further development of research in this field.

  8. Religion in meaning making and boundary work: theoretical explorations.

    PubMed

    Dahinden, Janine; Zittoun, Tania

    2013-06-01

    Based on the articles brought together for this special issue, this article proposes a transversal analysis and theoretical elaboration of the question of the uses of religious elements for meaning making and boundary work. In order to do so, we will first propose a sociocultural psychological perspective to examine meaning making dynamics. Second, we will apply a boundary work perspective, as recently developed in the social sciences, on the organization of religious differences. The first considers religious elements as resources that can be used by people to orient themselves in time and the social space, to interpret and guide action, and to create new forms of life. The second approach proposes an analysis of uses of religious stuff in order to understand how boundaries between groups are created, transgressed or dissolved as well as to explore the link between religion and power. Our argument is that the articulation of these two approaches can itself offer a rich theoretical frame to apprehend religions in contemporary society.

  9. [ORGANIZATIONAL COMMITMENT AND WORK ENGAGEMENT - THEORETICAL CONCEPTIONS AND TERMINOLOGICAL PROBLEMS].

    PubMed

    Łaguna, Mariola; Mielniczuk, Emilia; Żaliński, Adam; Wałachowska, Karolina

    2015-01-01

    Engagement in professional activities and positive attitudes towards an organization are of significant importance to functioning and health of employees. Studies analysing the phenomena of employees' engagement and their relations with an organization undergo a dynamic development in both international and Polish research. Two theoretical conceptions: organizational commitment (by Meyer and Allen) and work engagement (by Schaufeli and Bakker) have become prominent in the field. They capture 2 similar, albeit distinct constructs. In English-language journals academics concentrate on theoretical and empirical analyses of similarities and differences between the 2 concepts, while in Polish publications scholars also have to deal with the issue of the original term translation. The problem lies mostly in Polish nomenclature of the dimensions proposed in both of these conceptions. Lack of common translations for different studies may cause confusion in this area of research. In the paper authors present a review of Polish translations of terms used in the discussed conceptions and a linguistic analysis of terms, both in English and in Polish. Authors provide solutions which could help to clarify terminology in Polish-language publications concerning organizational commitment and work engagement. This allows for further development of research in this field. PMID:26294317

  10. Approximate additions and working memory in individuals with Down syndrome.

    PubMed

    Belacchi, Carmen; Passolunghi, Maria Chiara; Brentan, Elena; Dante, Arianna; Persi, Lara; Cornoldi, Cesare

    2014-05-01

    There is some evidence that individuals with Down syndrome (DS) may have a poorer mathematical performance and a poorer working memory (WM) than typically developing (TD) children of the same mental age. In both typical and atypical individuals, different aspects of arithmetic and their relationships with WM have been largely studied, but the specific contribution of WM to the representation and elaboration of non-symbolic quantities has received little attention. The present study examined whether individuals with DS are as capable as TD children matched for fluid intelligence of estimating numerosity both of single sets and of added sets resulting when two sequentially presented sets are added together, also considering how these tasks related to verbal and visuospatial WM. Results showed that the DS group's performance was significantly worse than the TD group's in numerosity estimation involving one set, but not when estimating the numerosity resulting from the addition. Success in the addition task was related to success in the working memory tasks, but only for the group with DS; this applied especially to the visuospatial component, which (unlike the verbal component) was not impaired in the group with DS. It is concluded that the two numerosity tasks involve different processes. It is concluded that the arithmetical and working memory difficulties of individuals with DS are not general, and they can draw on their WM resources when estimating the numerosity of additions. PMID:24602332

  11. The guanidine and maleic acid (1:1) complex. The additional theoretical and experimental studies

    NASA Astrophysics Data System (ADS)

    Drozd, Marek; Dudzic, Damian

    2012-04-01

    On the basis of experimental literature data the theoretical studies for guanidinium and maleic acid complex with using DFT method are performed. In these studies the experimental X-ray data for two different forms of investigated crystal were used. During the geometry optimization process one equilibrium structure was found, only. According to this result the infrared spectrum for one theoretical molecule was calculated. On the basis of potential energy distribution (PED) analysis the clear-cut assignments of observed bands were performed. For the calculated molecule with energy minimum the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were obtained and graphically illustrated. The energy difference (GAP) between HOMO and LUMO was analyzed. Additionally, the nonlinear properties of this molecule were calculated. The α and β (first and second order) hyperpolarizability values are obtained. On the basis of these results the title crystal was classified as new second order NLO generator.

  12. Working with the Terminally Ill: An Integrated Theoretical Model.

    ERIC Educational Resources Information Center

    Martins, John R.

    This introduction and outline correspond to a presentation at the American Counseling Association (ACA) 1999 World Conference. The author recounts his psychotherapeutic work with young gay men diagnosed with AIDS and his increasing awareness of their movement toward psychological health and the development of a deeper spirituality. His quest…

  13. Lee Pedersen's work in theoretical and computational chemistry and biochemistry.

    PubMed

    Pedersen, Lee G

    2011-02-26

    Nature at the lab level in biology and chemistry can be described by the application of quantum mechanics. In many cases, a reasonable approximation to quantum mechanics is classical mechanics realized through Newton's equations of motion. Dr. Pedersen began his career using quantum mechanics to describe the properties of small molecular complexes that could serve as models for biochemical systems. To describe large molecular systems required a drop-back to classical means and this led surprisingly to a major improvement in the classical treatment of electrostatics for all molecules, not just biological molecules. Recent work has involved the application of quantum mechanics for the putative active sites of enzymes to gain greater insight into the key steps in enzyme catalysis.

  14. Mechanisms on electrical breakdown strength increment of polyethylene by aromatic carbonyl compounds addition: a theoretical study.

    PubMed

    Zhang, Hui; Shang, Yan; Wang, Xuan; Zhao, Hong; Han, Baozhong; Li, Zesheng

    2013-12-01

    A theoretical investigation is accomplished on the mechanisms of electrical breakdown strength increment of polyethylene at the atomic and molecular levels. It is found that the addition of aromatic carbonyl compounds as voltage stabilizers is one of the important factors for increasing electrical breakdown strength of polyethylene, as the additives can trap hot electrons, obtain energy of hot electrons, and transform the aliphatic cation to relatively stable aromatic cation to prevent the degradation of the polyethylene matrix. The HOMO-LUMO energy gaps (E(g)), the ionization potentials (IPs), and electron affinities (EAs) at the ground states of a series of aromatic carbonyl compounds are obtained at the B3LYP/6-311+G(d,p) level. The theoretical results are in good agreement with the available experimental findings, show that 2,4-dioctyloxybenzophenone (Bzo) and 4,4'-didodecyloxybenzil (Bd) molecules can effectively increase the electrical breakdown strength when they are doped into polyethylene because of their much smaller E g values than all the other studied aromatic carbonyl molecules and excellent compatibility with polymers matrix.

  15. From dodo bird to mindfulness: the effect of theoretical orientation on work and self.

    PubMed

    Pruitt, Nathan T

    2014-08-01

    I discuss my transformation from a confused graduate student with a common factors theoretical orientation to a licensed psychologist focused on humanistic, cognitive, and mindfulness approaches. My theoretical journey was shaped by my work with clients and my own personal development and primarily motivated by a sense of uncertainty that accompanied the lack of a specific theoretical identity. This discussion of trying to find the "right" theoretical approach is set against the well-supported empirical findings that theoretical techniques (i.e., "specific factors") contribute relatively little to clinical outcome, and that no single theoretical approach has distinguished itself as superior to others in the literature. I discuss the effects of my theoretical orientations on my work with colleagues, my relationship with my spouse, and being a parent. PMID:24953554

  16. From dodo bird to mindfulness: the effect of theoretical orientation on work and self.

    PubMed

    Pruitt, Nathan T

    2014-08-01

    I discuss my transformation from a confused graduate student with a common factors theoretical orientation to a licensed psychologist focused on humanistic, cognitive, and mindfulness approaches. My theoretical journey was shaped by my work with clients and my own personal development and primarily motivated by a sense of uncertainty that accompanied the lack of a specific theoretical identity. This discussion of trying to find the "right" theoretical approach is set against the well-supported empirical findings that theoretical techniques (i.e., "specific factors") contribute relatively little to clinical outcome, and that no single theoretical approach has distinguished itself as superior to others in the literature. I discuss the effects of my theoretical orientations on my work with colleagues, my relationship with my spouse, and being a parent.

  17. Theoretical Additional Span Loading Characteristics of Wings with Arbitrary Sweep, Aspect Ratio, and Taper Ratio

    NASA Technical Reports Server (NTRS)

    Deyoung, John

    1947-01-01

    The Weissinger method for determining additional span loading has been used to find the lift-curve slope, spanwise center of pressure, aerodynamic center location, and span loading coefficients of untwisted and uncambered wings having a wide range of plan forms characterized by various combinations of sweep, aspect ratio, and taper ratio. The results are presented as variations of the aerodynamic characteristics with sweep angle for various values of aspect ratio and taper ratio. Methods are also included for determining induced drag and the approximate effects of compressibility. Despite the limitations of a lifting line method such as Weissinger's, the good agreement found between experimentally and theoretically determined characteristics warrants confidence in the method. In particular, it is believed that trends observed in results of the Weissinger method should be reliable. One of the most significant results showed that for each angle of sweep there is a taper ratio for which aspect ratio has little effect on the span loading and for which the loading is practically elliptical. This elliptic loading is approached at a taper ratio of 1.39 for 30 degree of sweepforward, 0.45 for zero degree of sweepback. (author)

  18. Experimental and theoretical work on excitation and excitation-contraction coupling in the heart.

    PubMed

    Noble, D

    1987-12-01

    A combination of experimental and theoretical work has been used to investigate the movements of calcium during cardiac excitation. In addition to calcium entry through several types of calcium channel, calcium efflux occurs to balance the entry during each cycle of activity. Measurements of net membrane calcium movements have been made with the right time resolution by Don Hilgemann in Los Angeles by investigating fast extracellular calcium transients. This work shows that, in mammalian cardiac cells, net calcium exit occurs quite early during repolarization and is nearly complete by the time the resting potential is re-established. These results correlate very well indeed with measurements made in the Oxford laboratory of calcium-activated inward current in single cardiac myocytes. Both approaches are consistent with the view that calcium efflux occurs largely through the sodium-calcium exchange process. Modelling of this process in equations developed recently with Dario DiFrancesco, Susan Noble and Don Hilgemann succeeds in reproducing both the ionic current changes and the fast extracellular calcium transients.

  19. A Heated Debate: Theoretical Perspectives of Sexual Exploitation and Sex Work

    PubMed Central

    Gerassi, Lara

    2015-01-01

    The theoretical and often political framework of sexual exploitation and sex work among women is widely and enthusiastically debated among academic and legal scholars alike. The majority of theoretical literature in this area focuses on the macro perspective, while the micro-level perspective as to theory and causation remains sparse. This article provides a comprehensive overview of the philosophical, legal, and political perspectives pertaining to sexual exploitation of women and girls while addressing the subsequent controversies in the field. PMID:26834302

  20. 46 CFR 167.43-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Additional requirements for hybrid work vests. 167.43-25... PUBLIC NAUTICAL SCHOOL SHIPS Work Vests § 167.43-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  1. 46 CFR 78.36-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Additional requirements for hybrid work vests. 78.36-25... OPERATIONS Work Vests § 78.36-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in...

  2. 46 CFR 78.36-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Additional requirements for hybrid work vests. 78.36-25... OPERATIONS Work Vests § 78.36-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in...

  3. 46 CFR 97.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Additional requirements for hybrid work vests. 97.34-25... VESSELS OPERATIONS Work Vests § 97.34-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  4. 46 CFR 196.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Additional requirements for hybrid work vests. 196.34-25... VESSELS OPERATIONS Work Vests § 196.34-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  5. 46 CFR 97.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Additional requirements for hybrid work vests. 97.34-25... VESSELS OPERATIONS Work Vests § 97.34-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  6. 46 CFR 196.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Additional requirements for hybrid work vests. 196.34-25... VESSELS OPERATIONS Work Vests § 196.34-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  7. 46 CFR 167.43-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Additional requirements for hybrid work vests. 167.43-25... PUBLIC NAUTICAL SCHOOL SHIPS Work Vests § 167.43-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  8. 46 CFR 167.43-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Additional requirements for hybrid work vests. 167.43-25... PUBLIC NAUTICAL SCHOOL SHIPS Work Vests § 167.43-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  9. 46 CFR 78.36-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Additional requirements for hybrid work vests. 78.36-25... OPERATIONS Work Vests § 78.36-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in...

  10. 46 CFR 97.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Additional requirements for hybrid work vests. 97.34-25... VESSELS OPERATIONS Work Vests § 97.34-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  11. 46 CFR 167.43-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Additional requirements for hybrid work vests. 167.43-25... PUBLIC NAUTICAL SCHOOL SHIPS Work Vests § 167.43-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  12. 46 CFR 97.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Additional requirements for hybrid work vests. 97.34-25... VESSELS OPERATIONS Work Vests § 97.34-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  13. 46 CFR 196.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Additional requirements for hybrid work vests. 196.34-25... VESSELS OPERATIONS Work Vests § 196.34-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  14. 46 CFR 97.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Additional requirements for hybrid work vests. 97.34-25... VESSELS OPERATIONS Work Vests § 97.34-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  15. 46 CFR 78.36-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Additional requirements for hybrid work vests. 78.36-25... OPERATIONS Work Vests § 78.36-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in...

  16. 46 CFR 78.36-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Additional requirements for hybrid work vests. 78.36-25... OPERATIONS Work Vests § 78.36-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in...

  17. 46 CFR 196.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Additional requirements for hybrid work vests. 196.34-25... VESSELS OPERATIONS Work Vests § 196.34-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  18. 46 CFR 167.43-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Additional requirements for hybrid work vests. 167.43-25... PUBLIC NAUTICAL SCHOOL SHIPS Work Vests § 167.43-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed,...

  19. Theoretical study of the hydroxyl radical addition to uracil and photochemistry of the formed U6OH• adduct.

    PubMed

    Francés-Monerris, Antonio; Merchán, Manuela; Roca-Sanjuán, Daniel

    2014-03-20

    Hydroxyl radical ((•)OH) is produced in biological systems by external or endogenous agents. It can damage DNA/RNA by attacking pyrimidine nucleobases through the addition to the C5═C6 double bond. The adduct resulting from the attachment at the C5 position prevails in the experimental measurements, although the reasons for this preference remain unclear. The first aim of this work is therefore to shed light on the comprehension of this important process. Thus, the thermal (•)OH addition to the C5═C6 double bond of uracil has been studied theoretically by using DFT, MP2, and the multiconfigurational CASPT2//CASSCF methodologies. The in-vacuo results obtained with the latter protocol plus the analysis of solvent effects support the experimental observation. A significant lower barrier height is predicted for the C5 pathway with respect to that of the C6 route. In contrast to the C5 adduct, the C6 adduct is able to absorb visible light. Hence, the second aim of the work is to study the photochemistry of this species using the CASPT2//CASSCF methodology within the framework of the photochemical reaction path approach (PRPA). The nonradiative decay to the ground state of this compound has been characterized. A photoreactive character is predicted for the C6 adduct in the excited states according to the presence of excited-state minima along the main decay channel. Finally, a new mechanism of photodissociation has been explored, which implies the photoinduced regeneration of the canonical nucleobase by irradiating with visible light, being therefore relevant in RNA protection against damage by reactive oxygen species.

  20. 77 FR 4654 - Senior Community Service Employment Program; Final Rule, Additional Indicator on Volunteer Work

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-31

    ... on September 1, 2010. 75 FR 53786. Previously, an interim final rule (IFR) on performance measures... an Additional Indicator for Volunteer Work, on November 23, 2010. 75 FR 71514. The additional... benefits of volunteer work for the elderly and the positive impact their volunteer work has on the...

  1. 46 CFR 35.03-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Additional requirements for hybrid work vests. 35.03-25... § 35.03-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in accordance with...

  2. 46 CFR 35.03-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Additional requirements for hybrid work vests. 35.03-25... § 35.03-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in accordance with...

  3. 46 CFR 35.03-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Additional requirements for hybrid work vests. 35.03-25... § 35.03-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in accordance with...

  4. 46 CFR 35.03-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Additional requirements for hybrid work vests. 35.03-25... § 35.03-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in accordance with...

  5. 46 CFR 35.03-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Additional requirements for hybrid work vests. 35.03-25... § 35.03-25 Additional requirements for hybrid work vests. (a) In addition to the other requirements in this subpart, commercial hybrid PFD's must be— (1) Used, stowed, and maintained in accordance with...

  6. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  7. Color and psychological functioning: a review of theoretical and empirical work.

    PubMed

    Elliot, Andrew J

    2015-01-01

    In the past decade there has been increased interest in research on color and psychological functioning. Important advances have been made in theoretical work and empirical work, but there are also important weaknesses in both areas that must be addressed for the literature to continue to develop apace. In this article, I provide brief theoretical and empirical reviews of research in this area, in each instance beginning with a historical background and recent advancements, and proceeding to an evaluation focused on weaknesses that provide guidelines for future research. I conclude by reiterating that the literature on color and psychological functioning is at a nascent stage of development, and by recommending patience and prudence regarding conclusions about theory, findings, and real-world application. PMID:25883578

  8. Theoretical foundations guiding culture change: The work of the Partnerships in Dementia Care Alliance

    PubMed Central

    Dupuis, Sherry; McAiney, Carrie A; Ploeg, Jenny; de Witt, Lorna

    2016-01-01

    Longstanding concerns about quality care provision, specifically in the area of long-term care, have prompted calls for changing the culture of care to reflect more client-driven and relationship-centred models. Despite an increase in culture change initiatives in both Canada and the United States, there is insufficient information about the theories and approaches that guide culture change. The purpose of this paper is to describe a culture change initiative currently underway in Canada, the Partnerships in Dementia Care Alliance, and the theoretical foundations informing our work. More specifically, we describe how the theoretical and philosophical underpinnings of the Alzheimer Disease and Related Dementias framework, the authentic partnership approach, participatory action research and Appreciative Inquiry have been integrated to guide a culture change process that encourages working collaboratively, thinking and doing differently and re-imagining new possibilities for changing the culture of dementia care. PMID:24419355

  9. Color and psychological functioning: a review of theoretical and empirical work

    PubMed Central

    Elliot, Andrew J.

    2015-01-01

    In the past decade there has been increased interest in research on color and psychological functioning. Important advances have been made in theoretical work and empirical work, but there are also important weaknesses in both areas that must be addressed for the literature to continue to develop apace. In this article, I provide brief theoretical and empirical reviews of research in this area, in each instance beginning with a historical background and recent advancements, and proceeding to an evaluation focused on weaknesses that provide guidelines for future research. I conclude by reiterating that the literature on color and psychological functioning is at a nascent stage of development, and by recommending patience and prudence regarding conclusions about theory, findings, and real-world application. PMID:25883578

  10. The inherence heuristic: a key theoretical addition to understanding social stereotyping and prejudice.

    PubMed

    Bigler, Rebecca S; Clark, Caitlin

    2014-10-01

    Prior work has detailed the constructivist processes that lead individuals to categorize others along particular dimensions (e.g., gender) and generate the content (e.g., stereotypes) and affect (e.g., prejudices) associated with social groups. The inherence heuristic is a novel mechanism that appears to shape the content and rigidity of children's social stereotypes and prejudices. PMID:25388029

  11. The inherence heuristic: a key theoretical addition to understanding social stereotyping and prejudice.

    PubMed

    Bigler, Rebecca S; Clark, Caitlin

    2014-10-01

    Prior work has detailed the constructivist processes that lead individuals to categorize others along particular dimensions (e.g., gender) and generate the content (e.g., stereotypes) and affect (e.g., prejudices) associated with social groups. The inherence heuristic is a novel mechanism that appears to shape the content and rigidity of children's social stereotypes and prejudices.

  12. Theoretical and experimental investigation of design for multioptical-axis freeform progressive addition lenses

    NASA Astrophysics Data System (ADS)

    Xiang, HuaZhong; Chen, JiaBi; Zhu, TianFen; Wei, YeFei; Fu, DongXiang

    2015-11-01

    A freeform progressive addition lens (PAL) provides a good solution to correct presbyopia and prevent juvenile myopia by distributing pupils' optical powers of distance zone, near zone, and intermediate zone and is more widely adopted in the present optometric study. However, there is still a lack of a single-optical-axis system for the design of a PAL. This paper focuses on the research for an approach for designing a freeform PAL. A multioptical-axis system based on real viewing conditions using the eyes is employed for the representation of the freeform surface. We filled small pupils in the intermediate zone as a progressive corridor and the distance- and near-vision portions were defined as the standard spherical surfaces delimited by quadratic curves. Three freeform PALs with a spherical surface as the front side and a freeform surface as the backside were designed. We demonstrate the fabrication and measurement technologies for the PAL surface using computer numerical control machine tools from Schneider Smart and a Visionix VM-2000 Lens Power Mapper. Surface power and astigmatic values were obtained. Preliminary results showed that the approach for the design and fabrication is helpful to advance the design procedure optimization and mass production of PALs in optometry.

  13. A theoretical study of wave dispersion and thermal conduction for HMX/additive interfaces

    NASA Astrophysics Data System (ADS)

    Long, Yao; Chen, Jun

    2014-04-01

    The wave dispersion rule for non-uniform material is useful for ultrasonic inspection and engine life prediction, and also is key in achieving an understanding of the energy dissipation and thermal conduction properties of solid material. On the basis of linear response theory and molecular dynamics, we derive a set of formulas for calculating the wave dispersion rate of interface systems, and study four kinds of interfaces inside plastic bonded explosives: HMX/{HMX, TATB, F2312, F2313}. (HMX: octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine; TATB: 1,3,5-triamino-2,4,6-trinitrobenzene; F2312, F2313: fluoropolymers). The wave dispersion rate is obtained over a wide frequency range from kHz to PHz. We find that at low frequency, the rate is proportional to the square of the frequency, and at high frequency, the rate couples with the molecular vibration modes at the interface. By using the results, the thermal conductivities of HMX/additive interfaces are derived, and a physical model is built for describing the total thermal conductivity of mixture explosives, including HMX multi-particle systems and {TATB, F2312, F2313}-coated HMX.

  14. Planning additional drilling campaign using two-space genetic algorithm: A game theoretical approach

    NASA Astrophysics Data System (ADS)

    Kumral, Mustafa; Ozer, Umit

    2013-03-01

    Grade and tonnage are the most important technical uncertainties in mining ventures because of the use of estimations/simulations, which are mostly generated from drill data. Open pit mines are planned and designed on the basis of the blocks representing the entire orebody. Each block has different estimation/simulation variance reflecting uncertainty to some extent. The estimation/simulation realizations are submitted to mine production scheduling process. However, the use of a block model with varying estimation/simulation variances will lead to serious risk in the scheduling. In the medium of multiple simulations, the dispersion variances of blocks can be thought to regard technical uncertainties. However, the dispersion variance cannot handle uncertainty associated with varying estimation/simulation variances of blocks. This paper proposes an approach that generates the configuration of the best additional drilling campaign to generate more homogenous estimation/simulation variances of blocks. In other words, the objective is to find the best drilling configuration in such a way as to minimize grade uncertainty under budget constraint. Uncertainty measure of the optimization process in this paper is interpolation variance, which considers data locations and grades. The problem is expressed as a minmax problem, which focuses on finding the best worst-case performance i.e., minimizing interpolation variance of the block generating maximum interpolation variance. Since the optimization model requires computing the interpolation variances of blocks being simulated/estimated in each iteration, the problem cannot be solved by standard optimization tools. This motivates to use two-space genetic algorithm (GA) approach to solve the problem. The technique has two spaces: feasible drill hole configuration with minimization of interpolation variance and drill hole simulations with maximization of interpolation variance. Two-space interacts to find a minmax solution

  15. 48 CFR 1352.271-72 - Additional Item Requirements (AIR)-growth work

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Clauses 1352.271-72 Additional Item Requirements (AIR)—growth work As prescribed in 48 CFR 1371.103... Cleaning/Water Blasting, Tank Cleaning, Welding, Burning, Brazing, Blacksmithing, Machining (inside...

  16. 48 CFR 1352.271-72 - Additional Item Requirements (AIR)-growth work

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Clauses 1352.271-72 Additional Item Requirements (AIR)—growth work As prescribed in 48 CFR 1371.103... Cleaning/Water Blasting, Tank Cleaning, Welding, Burning, Brazing, Blacksmithing, Machining (inside...

  17. 48 CFR 1352.271-72 - Additional Item Requirements (AIR)-growth work

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Clauses 1352.271-72 Additional Item Requirements (AIR)—growth work As prescribed in 48 CFR 1371.103... alteration, modification, or repair. The following functions are identified as direct production:...

  18. 48 CFR 1352.271-72 - Additional Item Requirements (AIR)-growth work

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Clauses 1352.271-72 Additional Item Requirements (AIR)—growth work As prescribed in 48 CFR 1371.103... alteration, modification, or repair. The following functions are identified as direct production:...

  19. 48 CFR 1352.271-72 - Additional Item Requirements (AIR)-growth work

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... include: Testing, Quality Assurance (inspection), Engineering (support), Planning (including involvement... Clauses 1352.271-72 Additional Item Requirements (AIR)—growth work As prescribed in 48 CFR 1371.103..., Painting, Boilermaking, Pipe Fitting, Engineering (Production), Sheetmetal Work, Staging/Scaffolding,...

  20. How beauty works. Theoretical mechanisms and two empirical applications on students' evaluation of teaching.

    PubMed

    Wolbring, Tobias; Riordan, Patrick

    2016-05-01

    Plenty of studies show that the physical appearance of a person affects a variety of outcomes in everyday life. However, due to an incomplete theoretical explication and empirical problems in disentangling different beauty effects, it is unclear which mechanisms are at work. To clarify how beauty works we present explanations from evolutionary theory and expectation states theory and show where both perspectives differ and where interlinkage appears promising. Using students' evaluations of teaching we find observational and experimental evidence for the different causal pathways of physical attractiveness. First, independent raters strongly agree over the physical attractiveness of a person. Second, attractive instructors receive better student ratings. Third, students attend classes of attractive instructors more frequently - even after controlling for teaching quality. Fourth, we find no evidence that attractiveness effects become stronger if rater and ratee are of the opposite sex. Finally, the beauty premium turns into a penalty if an attractive instructor falls short of students' expectations. PMID:26973043

  1. How beauty works. Theoretical mechanisms and two empirical applications on students' evaluation of teaching.

    PubMed

    Wolbring, Tobias; Riordan, Patrick

    2016-05-01

    Plenty of studies show that the physical appearance of a person affects a variety of outcomes in everyday life. However, due to an incomplete theoretical explication and empirical problems in disentangling different beauty effects, it is unclear which mechanisms are at work. To clarify how beauty works we present explanations from evolutionary theory and expectation states theory and show where both perspectives differ and where interlinkage appears promising. Using students' evaluations of teaching we find observational and experimental evidence for the different causal pathways of physical attractiveness. First, independent raters strongly agree over the physical attractiveness of a person. Second, attractive instructors receive better student ratings. Third, students attend classes of attractive instructors more frequently - even after controlling for teaching quality. Fourth, we find no evidence that attractiveness effects become stronger if rater and ratee are of the opposite sex. Finally, the beauty premium turns into a penalty if an attractive instructor falls short of students' expectations.

  2. Theoretical investigation of the effect of hydrogen addition on the formation and properties of soliton in direct current argon plasma

    NASA Astrophysics Data System (ADS)

    Saikia, P.; Goswami, K. S.; Saikia, B. K.

    2014-03-01

    In this study the effect of hydrogen addition on the formation and properties of soliton in direct-current (DC) argon plasma is theoretically investigated. By coupling fluid equations with Poisons equation for such multi-component plasma, the Mach number and amplitude of the soliton are determined following pseudo potential method. Addition of hydrogen in argon discharge leads to the decrease of electron, Ar+ ion density while a reverse trend was observed for ArH+ and hydrogen like ions. It was found that presence of hydrogen like ions in argon plasma affects the formation of soliton with its amplitude significantly decreases as concentration of hydrogen increases. On the other hand, increase in ion to electron temperature ratios of the lighter ions in the discharge also has a significant influence on the amplitude and formation of soliton. The inverse relation between solitons width and amplitude is found to be consistent for the entire range of study.

  3. Theoretical investigation of the effect of hydrogen addition on the formation and properties of soliton in direct current argon plasma

    SciTech Connect

    Saikia, P. Goswami, K. S.; Saikia, B. K.

    2014-03-15

    In this study the effect of hydrogen addition on the formation and properties of soliton in direct-current (DC) argon plasma is theoretically investigated. By coupling fluid equations with Poisons equation for such multi-component plasma, the Mach number and amplitude of the soliton are determined following pseudo potential method. Addition of hydrogen in argon discharge leads to the decrease of electron, Ar{sup +} ion density while a reverse trend was observed for ArH{sup +} and hydrogen like ions. It was found that presence of hydrogen like ions in argon plasma affects the formation of soliton with its amplitude significantly decreases as concentration of hydrogen increases. On the other hand, increase in ion to electron temperature ratios of the lighter ions in the discharge also has a significant influence on the amplitude and formation of soliton. The inverse relation between solitons width and amplitude is found to be consistent for the entire range of study.

  4. Addition-fragmentation reaction of thionoesters compounds in free-radical polymerisation (methyl, cyanomethyl and styryl): a theoretical interpretation

    NASA Astrophysics Data System (ADS)

    Hannachi, Douniazed; Ouddai, Nadia; Arotçaréna, Michel; Chermette, Henry

    2015-07-01

    A joint experimental and theoretical study has been carried out on reversible addition-fragmentation chain transfer polymerisation (RAFT). We have performed density functional theory calculations at the (Perdew-Burke-Ernzerhof) PBE/triple zeta plus polarisation level to analyse the RAFT mechanisms corresponding to these compounds. Global and local reactivity indices have been calculated to investigate the effect of the addition of methyl, cyanomethyl and styryl radicals on the double bond C=S of thionoester compounds producing an adduct radical. This mechanism is shown to be difficult when the cyanomethyl is used contrarily to the methyl and styryl radicals, in agreement with experimental results. The activation barrier of fragmentation of adduct radicals does not correlate well with the length of fragmented bond (O-Cα). The bond topological analysis of radical adduct predicts that the distance between the oxygen and a critical point (O-CP) in the fragment bond is a good parameter to estimate the activation energy of the fragmentation mechanism. It is shown that the nature of the free radicals is more selective than that of the thionoester compounds. With an overall large agreement with experiments, these theoretical results afford an explanation of the efficiency for the RAFT mechanism.

  5. Work of Adhesion in Al/SiC Composites with Alloying Element Addition

    NASA Astrophysics Data System (ADS)

    Fang, Xin; Fan, Tongxiang; Zhang, Di

    2013-11-01

    In the current work, a general methodology was proposed to demonstrate how to calculate the work of adhesion in a reactive multicomponent alloy/ceramic system. Applying this methodology, the work of adhesion of Al alloy/SiC systems and the influence of different alloying elements were predicted. Based on the thermodynamics of interfacial reaction and calculation models for component activities, the equilibrium compositions of the melts in Al alloy/SiC systems were calculated. Combining the work of adhesion models for reactive metal/ceramic systems, the work of adhesion in Al alloy/SiC systems both before and after the reaction was calculated. The results showed that the addition of most alloying elements, such as Mg, Si, and Mn, could increase the initial work of adhesion, while Fe had a slightly decreasing effect. As for the equilibrium state, the additions of Cu, Fe, Mn, Ni, Ti, and La could increase the equilibrium work of adhesion, but the additions of Mg and Zn had an opposite effect. Si was emphasized due to its suppressing effect on the interfacial reaction.

  6. 46 CFR 196.34-25 - Additional requirements for hybrid work vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Additional requirements for hybrid work vests. 196.34-25 Section 196.34-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH... the same method of operation as each other hybrid PFD carried on board....

  7. The Involvement of Working Memory in Children's Exact and Approximate Mental Addition

    ERIC Educational Resources Information Center

    Caviola, Sara; Mammarella, Irene C.; Cornoldi, Cesare; Lucangeli, Daniela

    2012-01-01

    The involvement of working memory (WM) was examined in two types of mental calculation tasks: exact and approximate. Specifically, children attending Grades 3 and 4 of primary school were involved in three experiments that examined the role of verbal and visuospatial WM in solving addition problems presented in vertical or horizontal format. For…

  8. Theoretical study of the oxidation mechanisms of naphthalene initiated by hydroxyl radicals: the OH-addition pathway.

    PubMed

    Shiroudi, Abolfazl; Deleuze, Michael S; Canneaux, Sébastien

    2014-07-01

    The oxidation mechanisms of naphthalene by OH radicals under inert (He) conditions have been studied using density functional theory along with various exchange-correlation functionals. Comparison has been made with benchmark CBS-QB3 theoretical results. Kinetic rate constants were correspondingly estimated by means of transition state theory and statistical Rice-Ramsperger-Kassel-Marcus (RRKM) theory. Comparison with experiment confirms that, on the OH-addition reaction pathway leading to 1-naphthol, the first bimolecular reaction step has an effective negative activation energy around -1.5 kcal mol(-1), whereas this step is characterized by an activation energy around 1 kcal mol(-1) on the OH-addition reaction pathway leading to 2-naphthol. Effective rate constants have been calculated according to a steady state analysis upon a two-step model reaction mechanism. In line with experiment, the correspondingly obtained branching ratios indicate that, at temperatures lower than 410 K, the most abundant product resulting from the oxidation of naphthalene by OH radicals must be 1-naphthol. The regioselectivity of the OH(•)-addition onto naphthalene decreases with increasing temperatures and decreasing pressures. Because of slightly positive or even negative activation energies, the RRKM calculations demonstrate that the transition state approximation breaks down at ambient pressure (1 bar) for the first bimolecular reaction steps. Overwhelmingly high pressures, larger than 10(5) bar, would be required for restoring to some extent (within ∼5% accuracy) the validity of this approximation for all the reaction channels that are involved in the OH-addition pathway. Analysis of the computed structures, bond orders, and free energy profiles demonstrate that all reaction steps involved in the oxidation of naphthalene by OH radicals satisfy Leffler-Hammond's principle. Nucleus independent chemical shift indices and natural bond orbital analysis also show that the computed

  9. The involvement of working memory in children's exact and approximate mental addition.

    PubMed

    Caviola, Sara; Mammarella, Irene C; Cornoldi, Cesare; Lucangeli, Daniela

    2012-06-01

    The involvement of working memory (WM) was examined in two types of mental calculation tasks: exact and approximate. Specifically, children attending Grades 3 and 4 of primary school were involved in three experiments that examined the role of verbal and visuospatial WM in solving addition problems presented in vertical or horizontal format. For Experiment 1, the children were required to solve addition problems with carrying. For Experiment 2, they were required to solve addition problems without carrying. Then, for Experiment 3, the children needed to solve approximate problems with and without carrying. Results confirmed that different WM components are involved in solving mental addition problems. In Experiment 1, horizontally presented addition problems were more impaired than vertically presented ones, according to a verbal WM load; conversely, vertically presented addition problems were more affected by a visuospatial WM load, especially when the children were required to perform approximate calculations. In Experiment 2, this pattern emerged in neither exact nor approximate calculations. Finally, in Experiment 3, the specific involvement of WM components was observed only in problems with carrying. Overall, these results reveal that both approximate calculation and carrying procedures demand particularly high WM resources that vary according to the task's constraints. PMID:22436893

  10. Additional work of breathing imposed by endotracheal tubes, breathing circuits, and intensive care ventilators.

    PubMed

    Bersten, A D; Rutten, A J; Vedig, A E; Skowronski, G A

    1989-07-01

    A disadvantage of spontaneous breathing through an endotracheal tube (ETT) and connector attached to a breathing circuit and/or ventilator (breathing device) is an increase in the work of breathing. The work of breathing associated with ETT of 6 to 9-mm diameter and eight breathing devices was determined, using a lung simulator to mimic spontaneous inspiration at flow rates of 20 to 100 L/min and a tidal volume of 500 ml, at both zero end-expiratory pressure (ZEEP) and 10 cm H2O continuous positive airway pressure (CPAP). Work associated with the breathing devices alone (WCIR) ranged from -0.002 kg.m/L (Servo 900-C ventilator, 7-mm ETT, 20 L/min, ZEEP) to 0.1 kg.m/L (continuous flow circuit, 7-mm ETT, 100 L/min, CPAP), the latter representing 196% of the work of normal breathing. When the devices were attached to ETT, total apparatus work (WAPP) ranged from 0.009 kg.m/L (Mapleson-D circuit, 9-mm ETT, 20 L/min, ZEEP) to 0.25 kg.m/L (Drager EV-A, 6-mm ETT, 100 L/min, ZEEP), the latter representing 490% of the work of normal breathing. This additional work imposed by the ETT varied considerably among devices. Spontaneous breathing through modern ventilators, circuits and ETT imposes a burden of increased work, most of which is associated with the presence of the ETT and connector. Whether this burden represents an impediment to the weaning patient, or has training value for the ultimate resumption of unassisted spontaneous ventilation, remains to be determined.

  11. Theoretical investigation of the addition reaction of the aluminum chlorosilylenoid H2SiAlCl3 with ethylene.

    PubMed

    Zhang, Mingxia; Li, Wenzuo; Liu, Zhenbo; Li, Qingzhong; Cheng, Jianbo

    2016-07-01

    The addition reaction of the aluminum chlorosilylenoid H2SiAlCl3 with ethylene was investigated using the M06-2X and QCISD methods for the first time. The calculated results demonstrate that the addition reaction proceeds via two pathways: path I involves just one transition state, while path II involves two transition states. Path I is more feasible dynamically, as it has a lower barrier height than path II. The effect of the solvent CH2Cl2 was taken into consideration using the PCM model. The results indicated that the addition reaction is less likely to occur in CH2Cl2 solvent than in vacuum. This work has therefore highlighted a new pathway for the synthesis of silicon heterocyclic compounds. Graphical Abstract Relative energies (in kJ·mol(-1)) of the stationary points along the potential energy surfaces of the addition reaction of H2SiAlCl3 with C2H4 (values in parentheses were calculated in CH2Cl2 solvent). PMID:27271163

  12. Considerations about the theoretically expected crushing strength of tablets from binary powder mixtures: double layer tablets versus arithmetic additivity rule.

    PubMed

    Belda, Petra M; Mielck, Jobst B

    2006-11-01

    The theoretically expected breaking strength of tablets from powder mixtures is often calculated by the weighted arithmetic mean from the breaking strength of the single components, which corresponds to a linear interpolation. The validity of this additivity of fracture strength shall be evaluated by the underlying model of parallel couplings. It assumes the components linked in parallel with respect to the direction of loading during diametrical strength testing. Parallel couplings were experimentally realised by the preparation of double layer tablets from crystalline and spray-dried lactose on the one hand and from maltitol and metamizol-sodium on the other. Constant total true volumes of the single substances and of layered powders in varying ratios of true volume were compressed on an eccentric tabletting machine to constant geometric mean punch force. Simulated crushing profiles of parallel couplings were derived from force-displacement profiles measured during diametrical compression of the one-component tablets. At given finely graded deformation levels, the forces exerted by the components during loading were added in the proportion of the true volume fractions of the components in the coupling. The results from the experiments and from the simulations are in good accordance. They demonstrate that a linear change of the crushing strength in dependence on the true volume fraction of the components can only be assumed if the single components deform to the same extent up to the point of fracture. This behaviour was approximately found with the parallel lactose system. In all other cases it must be expected that the crushing strength of parallel systems will be lowered beneath the weighted arithmetic mean values or even below the crushing strength of the single components. The latter was observed with the maltitol-metamizol combinations. Thus, if tablets from binary powder mixtures exhibit a crushing strength depression, this is not necessarily an indication

  13. Inspiratory pressure support compensates for the additional work of breathing caused by the endotracheal tube.

    PubMed

    Brochard, L; Rua, F; Lorino, H; Lemaire, F; Harf, A

    1991-11-01

    Breathing through an endotracheal tube and a demand valve may increase the work performed by the respiratory muscles. Inspiratory pressure support (PS) is known to reduce this work and might therefore compensate for this increased requirement. To test this hypothesis, we measured the work of breathing (WOB) in 11 patients whose tracheas were intubated. Five had no intrinsic lung disease, but six had chronic obstructive lung disease. We compared WOB measurements taken under several sets of conditions: during assisted breathing at four levels of PS, during unassisted breathing and connection to a T-piece, and after extubation of the trachea. During unassisted breathing via the ventilator circuit (PS set at 0 cmH20), the WOB per minute was greater than that after extubation, with a mean increase (+/- standard deviation) of 68 +/- 38% (10.3 +/- 5.1 vs. 6.5 +/- 3.7 J.min-1, P less than 0.01). While breathing through the T-piece, the WOB was 27 +/- 18% greater than after tracheal extubation (8.2 +/- 5.1 vs. 6.5 +/- 3.7 J.min-1, P less than 0.05). The principal reason why inspiratory work decreased after extubation was that the ventilatory requirement decreased. For each patient, we determined retrospectively, after extubation, the level of PS that had reduced WOB to its postextubation value and obtained levels ranging from 3.4 to 14.4 cmH2O. The PS level at which additional WOB was compensated for, was greater in patients with chronic lung disease than in those free of lung disease (12.0 +/- 1.9 vs. 5.7 +/- 1.5 cm H2O, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Use of additive technologies for practical working with complex models for foundry technologies

    NASA Astrophysics Data System (ADS)

    Olkhovik, E.; Butsanets, A. A.; Ageeva, A. A.

    2016-07-01

    The article presents the results of research of additive technology (3D printing) application for developing a geometrically complex model of castings parts. Investment casting is well known and widely used technology for the production of complex parts. The work proposes the use of a 3D printing technology for manufacturing models parts, which are removed by thermal destruction. Traditional methods of equipment production for investment casting involve the use of manual labor which has problems with dimensional accuracy, and CNC technology which is less used. Such scheme is low productive and demands considerable time. We have offered an alternative method which consists in printing the main knots using a 3D printer (PLA and ABS) with a subsequent production of castings models from them. In this article, the main technological methods are considered and their problems are discussed. The dimensional accuracy of models in comparison with investment casting technology is considered as the main aspect.

  15. Appraising the Qualities of Social Work Students' Theoretical Knowledge: A Qualitative Exploration

    ERIC Educational Resources Information Center

    van Bommel, Marijke; Boshuizen, Henny P. A.; Kwakman, Kitty

    2012-01-01

    Higher professional education aims to prepare students for entering practice with an adequate theoretical body of knowledge. In constructivist programmes, authentic learning contexts and self-directed learning are assumed to support knowledge learning and the transition from education to practice. Through an in-depth exploration, this case study…

  16. Theoretical investigation on mechanism of asymmetric Michael addition of malononitrile to chalcones catalyzed by Cinchona alkaloid aluminium(III) complex.

    PubMed

    Su, Zhishan; Lee, Hai Whang; Kim, Chan Kyung

    2011-09-21

    The mechanism of Michael addition of malononitrile to chalcones catalyzed by Cinchona alkaloid aluminium(III) complex has been investigated by DFT and ONIOM methods. Calculations indicate that the reaction proceeds through a dual activation mechanism, in which Al(III) acts as a Lewis acid to activate the electrophile α,β-unsaturated carbonyl substrate while the tertiary amine in the Cinchona alkaloid works as a Lewis base to promote the activation of the malononitrile and deprotonation. A stepwise pathway involving C-C bond formation followed by proton transfer from the catalyst to the carbonyl substrate is adopted, and latter step is predicted to be the rate-determining-step in the reaction with an energy barrier of 12.4 kcal mol(-1). In the absence of the Al(III)-complex, a Cinchona alkaloid activates the carbonyl substrate by a hydrogen bonding of the hydroxyl group, involving a higher energy barrier of 30.4 kcal mol(-1). The steric repulsion between the phenyl group attached to the carbonyl group in the chalcone and isopropoxyl groups of the Al(III)-complex may play an important role in the control of stereoselectivity. The π-π stacking effect between the quinuclidine ring of the quinine and the phenyl group of the chalcones may also help the stabilization of the preferred molecular complex. These results are in agreement with experimental observations. PMID:21796318

  17. University of Wolverhampton Case Study: Embedding Practical Work-Based Modules into a Traditionally, Theoretical Programme

    ERIC Educational Resources Information Center

    Nicholls, Emma; Walsh, Margaret

    2007-01-01

    Purpose: This case study aims to provide a critical evaluation of the decision by the University of Wolverhampton's School of Legal Studies to develop a number of work-based learning modules, offered as part of the undergraduate programme. It seeks to examine why the School has taken the approach of embedding work-based learning into what has…

  18. Suffering and Meaning in Counseling Service Work: Theoretical Foundations and Therapeutic Responses

    ERIC Educational Resources Information Center

    Eells, Gregory T.

    2012-01-01

    Working in a counseling service at a college or university often requires counselors to touch the deep foundation of suffering that underlies the human experience. This article will examine the philosophical underpinning of the ways in which our profession helps us respond to human suffering. I will first examine the roots of our daily work found…

  19. Working Memory and Science Education: Exploring the Compatibility of Theoretical Approaches

    ERIC Educational Resources Information Center

    St. Clair-Thompson, H. L.; Botton, C.

    2009-01-01

    Research in science education has referred to limitations in information processing resulting from both mental capacity and working memory capacity. Mental capacity is often conceptualised within the framework of the theory of constructive operators. However, the cognitive resources underlying working memory are not well specified within the…

  20. Emotion-Work Performance among Dual-Earner Couples: Testing Four Theoretical Perspectives

    ERIC Educational Resources Information Center

    Minnotte, Krista Lynn; Stevens, Daphne Pedersen; Minnotte, Michael C.; Kiger, Gary

    2007-01-01

    This study compares four theories of domestic labor in their ability to predict relative emotion-work performance among dual-earner couples. Specifically, the authors investigate the effects of gender ideology, time availability, relative resources, and crossover factors on the dependent variable of relative emotion-work performance using…

  1. Work and Inter-subjectivity: a theoretical reflection on its dialectics in the field of health and nursing.

    PubMed

    Carvalho, Brígida Gimenez; Peduzzi, Marina; Mandú, Edir Nei Teixeira; Ayres, José Ricardo de Carvalho Mesquita

    2012-01-01

    This theoretical reflection intends to show the inter-subjective relationship that takes place in health and nursing practices under the following theoretical perspectives: Institutional Analysis, Psychodynamics of Labor and the Theory of Communicative Action, with an emphasis on the latter. Linking these concepts to the Marxist approach to work in the field of health emerges from recognizing the need for its continuous reconstruction-in this case, with a view to understand the interaction and communication intrinsic to work in action. The theory of Communicative Action seeks to consider these two inextricable dimensions: work as productive action and as interaction. The first corresponds to instrumental action based on technical rules with a production-guided rationale. The second refers to the interaction that takes place as communicative action and seeks understanding among subjects. We assume that adopting this theoretical perspective in the analysis of health and nursing practices opens new possibilities for clarifying its social and historical process and inter-subjective connections. PMID:22481717

  2. Theoretical studies of the work functions of Pd-based bimetallic surfaces

    SciTech Connect

    Ding, Zhao-Bin; Wu, Feng; Wang, Yue-Chao; Jiang, Hong

    2015-06-07

    Work functions of Pd-based bimetallic surfaces, including mainly M/Pd(111), Pd/M, and Pd/M/Pd(111) (M = 4d transition metals, Cu, Au, and Pt), are studied using density functional theory. We find that the work function of these bimetallic surfaces is significantly different from that of parent metals. Careful analysis based on Bader charges and electron density difference indicates that the variation of the work function in bimetallic surfaces can be mainly attributed to two factors: (1) charge transfer between the two different metals as a result of their different intrinsic electronegativity, and (2) the charge redistribution induced by chemical bonding between the top two layers. The first factor can be related to the contact potential, i.e., the work function difference between two metals in direct contact, and the second factor can be well characterized by the change in the charge spilling out into vacuum. We also find that the variation in the work functions of Pd/M/Pd(111) surfaces correlates very well with the variation of the d-band center of the surface Pd atom. The findings in this work can be used to provide general guidelines to design new bimetallic surfaces with desired electronic properties.

  3. A Theoretical Model and New Test of Managerial Legitimacy in Work Teams

    ERIC Educational Resources Information Center

    Yoon, Jeongkoo; Thye, Shane

    2011-01-01

    This study examines endorsement and authorization as two social mechanisms that can induce perceptions of legitimacy for individuals who manage work teams. "Endorsement" is the support of a manager by one's own team members, whereas "authorization" is the support of a team manager stemming from a higher bureaucratic level. Applying these…

  4. Theoretical and Empirical Underpinnings of the What Works Clearinghouse Attrition Standard for Randomized Controlled Trials

    ERIC Educational Resources Information Center

    Deke, John; Chiang, Hanley

    2014-01-01

    Meeting the What Works Clearinghouse (WWC) attrition standard (or one of the attrition standards based on the WWC standard) is now an important consideration for researchers conducting studies that could potentially be reviewed by the WWC (or other evidence reviews). Understanding the basis of this standard is valuable for anyone seeking to meet…

  5. Relating Theory and Practice in Laboratory Work: A Variation Theoretical Study

    ERIC Educational Resources Information Center

    Eckerdal, Anna

    2015-01-01

    Computer programming education has practice-oriented as well as theory-oriented learning goals. Here, lab work plays an important role in students' learning. It is however widely reported that many students face great difficulties in learning theory as well as practice. This paper investigates the important but problematic relation between the…

  6. Life without Work: Understanding Social Class Changes and Unemployment through Theoretical Integration

    ERIC Educational Resources Information Center

    Ali, Saba Rasheed; Fall, Kevin; Hoffman, Tina

    2013-01-01

    Unemployment is a stark reality in today's economic climate, and many Americans report a fear of loss or decrease in social status as a result of unexpected unemployment. Despite vocational psychology's emphasis on work as a domain of life, very little exploration on how social class shifts impact workers has been conducted. One way to rectify the…

  7. How does curcumin work with poor bioavailability? Clues from experimental and theoretical studies

    PubMed Central

    Shen, Liang; Liu, Cui-Cui; An, Chun-Yan; Ji, Hong-Fang

    2016-01-01

    Curcumin is a natural product with multiple biological activities and numerous potential therapeutic applications. However, its poor systemic bioavailability fails to explain the potent pharmacological effects and hinders its clinical application. Using experimental and theoretical approaches, we compared curcumin and its degradation products for its biological activities against Alzheimer’s disease (AD), including the superoxide anion radical (O2.–)-scavenging activity, Aβ fibrils (fAβ) formation-inhibiting activity, and enzymatic inhibition activity. We showed that compared to the parent compound curcumin, the degradation products mixture possessed higher O2.–-scavenging activity and stronger inhibition against fAβ formation. The docking simulations revealed that the bioactive degradation products should make important contribution to the experimentally observed enzymatic inhibition activities of curcumin. Given that curcumin is readily degraded under physiological condition, our findings strongly suggested that the degradation products should make important contribution to the diverse biological activities of curcumin. Our novel findings not only provide novel insights into the complex pharmacology of curcumin due to its poor bioavailability, but also open new avenues for developing therapeutic applications of this natural product. PMID:26887346

  8. 48 CFR 1852.235-74 - Additional Reports of Work-Research and Development.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-Research and Development. 1852.235-74 Section 1852.235-74 Federal Acquisition Regulations System NATIONAL... Provisions and Clauses 1852.235-74 Additional Reports of Work—Research and Development. As prescribed in 1835.070(e), insert a clause substantially the same as the following: Additional Reports of...

  9. 48 CFR 1852.235-74 - Additional Reports of Work-Research and Development.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-Research and Development. 1852.235-74 Section 1852.235-74 Federal Acquisition Regulations System NATIONAL... Provisions and Clauses 1852.235-74 Additional Reports of Work—Research and Development. As prescribed in 1835.070(e), insert a clause substantially the same as the following: Additional Reports of...

  10. 48 CFR 1852.235-74 - Additional Reports of Work-Research and Development.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-Research and Development. 1852.235-74 Section 1852.235-74 Federal Acquisition Regulations System NATIONAL... Provisions and Clauses 1852.235-74 Additional Reports of Work—Research and Development. As prescribed in 1835.070(e), insert a clause substantially the same as the following: Additional Reports of...

  11. 48 CFR 1852.235-74 - Additional Reports of Work-Research and Development.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-Research and Development. 1852.235-74 Section 1852.235-74 Federal Acquisition Regulations System NATIONAL... Provisions and Clauses 1852.235-74 Additional Reports of Work—Research and Development. As prescribed in 1835.070(e), insert a clause substantially the same as the following: Additional Reports of...

  12. 48 CFR 1852.235-74 - Additional Reports of Work-Research and Development.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-Research and Development. 1852.235-74 Section 1852.235-74 Federal Acquisition Regulations System NATIONAL... Provisions and Clauses 1852.235-74 Additional Reports of Work—Research and Development. As prescribed in 1835.070(e), insert a clause substantially the same as the following: Additional Reports of...

  13. Theoretical study of the OH addition to the endocyclic and exocyclic double bonds of the d-limonene

    NASA Astrophysics Data System (ADS)

    Ramírez-Ramírez, Víctor M.; Nebot-Gil, Ignacio

    2005-06-01

    The initial step of the d-limonene + OH gas-phase reaction mechanism was investigated by means of ab initio calculations. We have considered eight different possibilities for the OH addition, corresponding to the two C-C double bonds, the two C atoms of each double bond, and the syn or anti orientation, with respect to the isopropenyl group (endocyclic attack) or the ring cycle (exocyclic attack). Activation energies calculated at the QCISD(T)/6-31G(d)//UMP2/6-31G(d) level, show that there are preferred orientations for the OH addition under atmospheric conditions of temperature and pressure.

  14. Working tools for theoretical chemistry: Polanyi, eyring, and debates over the "semiempirical method".

    PubMed

    Nye, Mary Jo

    2007-01-15

    Following along with the development of electron theory and quantum mechanics in the 1910s and 1920s, physical chemists began incorporating these new theories and approaches in their studies of activation energies, transition states, and chemical reactions for simple atomic and molecular systems. Among these chemists was Michael Polanyi, one of the founders of modern chemical dynamics, who collaborated with Henry Eyring in the development in the 1930s of a theory of the activated transition state and absolute reaction rates using potential energy surfaces and a semiempirical methodology. This paper examines the circumstances of their collaborative work, its reception, and its implications for further chemical research.

  15. Working tools for theoretical chemistry: Polanyi, eyring, and debates over the "semiempirical method".

    PubMed

    Nye, Mary Jo

    2007-01-15

    Following along with the development of electron theory and quantum mechanics in the 1910s and 1920s, physical chemists began incorporating these new theories and approaches in their studies of activation energies, transition states, and chemical reactions for simple atomic and molecular systems. Among these chemists was Michael Polanyi, one of the founders of modern chemical dynamics, who collaborated with Henry Eyring in the development in the 1930s of a theory of the activated transition state and absolute reaction rates using potential energy surfaces and a semiempirical methodology. This paper examines the circumstances of their collaborative work, its reception, and its implications for further chemical research. PMID:17143868

  16. Laboratory and theoretical work in the service of planetary atmospheric research

    NASA Astrophysics Data System (ADS)

    Coustenis, Athena

    2015-08-01

    A large quantity of observations is obtained by instruments onboard space missions exploring our solar system and by large ground-based telescopes observing the planets and also the exoplanets. Spectroscopy plays a major role in this type of investigation. To analyze and exploit these observations, planetary scientists need spectroscopic data covering wide ranges in wavelength but also in temperature, pressure, distance, etc.The outer regions of our solar system in particular, including the giant gaseous planets Jupiter and Saturn and their satellites, have recently been the target of space missions such as Cassini-Huygens and several investigations from the ground. Titan, the largest moon of Saturn, in particular, offers many similarities with our own planet, among which a dense atmosphere whose major component is dinitrogen at about 95%. Combining with methane (at a few percent) and hydrogen, gives rise to a complex organic chemistry with hydrocarbons and nitriles. Oxygen compounds also exist in Titan’s atmosphere. By studying Titan, we learn about our own planet and our Solar system Solar as a whole [1,2,3]. To properly interpret the Cassini-Huygens data and in anticipation of future missions like ESA’s JUICE to the Jupiter system, spectroscopic data are crucially needed. In the field of exoplanets (over 1000 discovered to date), it also becomes urgent to have adequate data of several molecules in order to analyze the observations returned to us every day by major observatories on Earth and in the space [4,5]. I will discuss recent applications from theoretical and experimental studies on the investigation of Titan and exoplanets, with emphasis on methane. I will also present some needs for future analyses.References: [1] Campargue, A., et al. 2012. Icarus 219, 110-128. [2] Coustenis, A., et al. 2013. Astrophys. J. 799, 177, 9p. [3] Hirtzig, et al., 2013. Icarus 226, 470-486 and corrigendum 1182-1182. [4] Tinetti, G., Encrenaz, Th., Coustenis, A., 2013

  17. Professional Competence Development of the Social Work Specialists in the Period of Study in the System of Additional Education

    ERIC Educational Resources Information Center

    Davletkaliev, Denis Kuanyshevich; Zueva, Natalia Konstantinovna; Lebedeva, Natalya Vasilevna; Mkrtumova, Irina Vladimirovna; Timofeeva, Olga

    2015-01-01

    The goal of this work is the study of psychological-pedagogical approaches to the understanding of the idea of professional competence of social work specialists as well as the role of study in the system of additional educations in professional-personal development of the listeners. In the process of study of this problem we define main…

  18. Additive Factors Do Not Imply Discrete Processing Stages: A Worked Example Using Models of the Stroop Task

    PubMed Central

    Stafford, Tom; Gurney, Kevin N.

    2011-01-01

    Previously, it has been shown experimentally that the psychophysical law known as Piéron’s Law holds for color intensity and that the size of the effect is additive with that of Stroop condition (Stafford et al., 2011). According to the additive factors method (Donders, 1868–1869/1969; Sternberg, 1998), additivity is assumed to indicate independent and discrete processing stages. We present computational modeling work, using an existing Parallel Distributed Processing model of the Stroop task (Cohen et al., 1990) and a standard model of decision making (Ratcliff, 1978). This demonstrates that additive factors can be successfully accounted for by existing single stage models of the Stroop effect. Consequently, it is not valid to infer either discrete stages or separate loci of effects from additive factors. Further, our modeling work suggests that information binding may be a more important architectural property for producing additive factors than discrete stages. PMID:22102842

  19. Dispersion interactions of carbohydrates with condensate aromatic moieties: theoretical study on the CH-π interaction additive properties.

    PubMed

    Kozmon, Stanislav; Matuška, Radek; Spiwok, Vojtěch; Koča, Jaroslav

    2011-08-21

    In this article we present the first systematic study of the additive properties (i.e. degree of additivity) of the carbohydrate-aromatic moiety CH-π dispersion interaction. The additive properties were studied on the β-D-glucopyranose, β-D-mannopyranose and α-L-fucopyranose complexes with the naphthalene molecule by comparing the monodentate (single CH-π) and bidentate (two CH-π) complexes. All model complexes were optimized using the DFT-D approach, at the BP/def2-TZVPP level of theory. The interaction energies were refined using single point calculations at highly correlated ab initio methods at the CCSD(T)/CBS level, calculated as E + (E(CCSD(T))-E(MP2))(Small Basis). Bidentate complexes show very strong interactions in the range from -10.79 up to -7.15 and -8.20 up to -6.14 kcal mol(-1) for the DFT-D and CCSD(T)/CBS level, respectively. These values were compared with the sum of interaction energies of the appropriate monodentate carbohydrate-naphthalene complexes. The comparison reveals that the bidentate complex interaction energy is higher (interaction is weaker) than the sum of monodentate complex interaction energies. Bidentate complex interaction energy corresponds to 2/3 of the sum of the appropriate monodentate complex interaction energies (averaging over all modeled carbohydrate complexes). The observed interaction energies were also compared with the sum of interaction energies of the corresponding previously published carbohydrate-benzene complexes. Also in this case the interaction energy of the bidentate complex was higher (i.e. weaker interaction) than the sum of interaction energies of the corresponding benzene complexes. However, the obtained difference is lower than before, while the bidentate complex interaction energy corresponds to 4/5 of the sum of interaction energy of the benzene complexes, averaged over all structures. The mentioned comparison might aid protein engineering efforts where amino acid residues phenylalanine or

  20. Work-Family Enrichment and Conflict: Additive Effects, Buffering, or Balance?

    ERIC Educational Resources Information Center

    Gareis, Karen C.; Barnett, Rosalind Chait; Ertel, Karen A.; Berkman, Lisa F.

    2009-01-01

    We used data from the Midlife Development in the United States (MIDUS I) (N = 2,031) to compare three models of how work-family conflict and enrichment might operate to predict well-being (mental health, life satisfaction, affect balance, partner relationship quality). We found no support for a relative-difference model in which the…

  1. A theoretical study of myoglobin working as a nitric oxide scavenger.

    PubMed

    Blomberg, L Mattias; Blomberg, Margareta R A; Siegbahn, Per E M

    2004-12-01

    The mechanism for the reaction between nitric oxide (NO) and O(2) bound to the heme iron of myoglobin (Mb), including the following isomerization to nitrate, has been investigated using hybrid density functional theory (B3LYP). Myoglobin working as a NO scavenger could be of importance, since NO reversibly inhibits the terminal enzyme in the respiration chain, cytochrome c oxidase. The concentration of NO in the cell will thus affect the respiration and thereby the synthesis of ATP. The calculations show that the reaction between NO and the heme-bound O(2) gives a peroxynitrite intermediate whose O-O bond undergoes a homolytic cleavage, forming a NO(2) radical and myoglobin in the oxo-ferryl state. The NO(2) radical then recombines with the oxo-ferryl, forming heme-bound nitrate. Nine different models have been used in the present study to examine the effect on the reaction both by the presence and the protonation state of the distal His64, and by the surroundings of the proximal His93. The barriers going from the oxy-Mb and nitric oxide reactant to the peroxynitrite intermediate and further to the oxo-ferryl and NO(2) radical are around 10 and 7 kcal/mol, respectively. Forming the product, nitrate bound to the heme iron has a barrier of less than approximately 7 kcal/mol. The overall reaction going from a free nitric oxide and oxy-Mb to the heme bound nitrate is exergonic by more than 30 kcal/mol.

  2. Causing Students to Choose More Language Arts Work: Enhancing the Validity of the Additive Interspersal Procedure

    ERIC Educational Resources Information Center

    Meadows, Sadonya F.; Skinner, Christopher H.

    2005-01-01

    Research on the additive interspersal procedure was extended by exposing seventh-grade students to curricula-based (e.g., educationally valid) language arts assignments. In Experiment I, each student was given a control language arts assignment containing 20 discrete target items and an experimental assignment containing 24 equivalent target…

  3. 1,4-Addition of bis(iodozincio)methane to α,β-unsaturated ketones: chemical and theoretical/computational studies.

    PubMed

    Sada, Mutsumi; Furuyama, Taniyuki; Komagawa, Shinsuke; Uchiyama, Masanobu; Matsubara, Seijiro

    2010-09-10

    1,4-Addition of bis(iodozincio)methane to simple α,β-unsaturated ketones does not proceed well; the reaction is slightly endothermic according to DFT calculations. In the presence of chlorotrimethylsilane, the reaction proceeded efficiently to afford a silyl enol ether of β-zinciomethyl ketone. The C--Zn bond of the silyl enol ether could be used in a cross-coupling reaction to form another C--C bond in a one-pot reaction. In contrast, 1,4-addition of the dizinc reagent to enones carrying an acyloxy group proceeded very efficiently without any additive. In this case, the product was a 1,3-diketone, which was generated in a novel tandem reaction. A theoretical/computational study indicates that the whole reaction pathway is exothermic, and that two zinc atoms of bis(iodozincio)methane accelerate each step cooperatively as effective Lewis acids. PMID:20645344

  4. Radionuclide release from spent fuel under geologic disposal conditions: An overview of experimental and theoretical work through 1985

    SciTech Connect

    Reimus, P.W.; Simonson, S.A.

    1988-04-01

    This report presents an overview of experimental and theoretical work on radionuclide release from spent fuel and uranium dioxide (UO/sub 2/) under geologic disposal conditions. The purpose of the report is to provide a source book of information that can be used to develop models that describe radionuclide release from spent fuel waste packages. Modeling activities of this nature will be conducted within the Waste Package Program (WPP) of the Department of Energy's Salt Repository Project (SRP). The topics discussed include experimental methods for investigating radionuclide release, how results have been reported from radionuclide release experiments, theoretical studies of UO/sub 2/ and actinide solubility, results of experimental studies of radionuclide release from spent fuel and UO/sub 2/ (i.e., the effects of different variables on radionuclide release), characteristics of spent fuel pertinent to radionuclide release, and status of modeling of radionuclide release from spent fuel. Appendix A presents tables of data from spent fuel radionuclide release experiments. These data have been digitized from graphs that appear in the literature. An annotated bibliography of literature on spent fuel characterization is provided in Appendix B.

  5. Theoretical characterization of the minimum energy path for hydrogen atom addition to N2 - Implications for the unimolecular lifetime of HN2

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Duchovic, Ronald J.; Rohlfing, Celeste Mcmichael

    1989-01-01

    Results are reported from CASSCF externally contracted CI ab initio computations of the minimum-energy path for the addition of H to N2. The theoretical basis and numerical implementation of the computations are outlined, and the results are presented in extensive tables and graphs and characterized in detail. The zero-point-corrected barrier for HN2 dissociation is estimated as 8.5 kcal/mol, and the lifetime of the lowest-lying quasi-bound vibrational state of HN2 is found to be between 88 psec and 5.8 nsec (making experimental observation of this species very difficult).

  6. Theoretical elucidation on the functional role of pyrrolidine-type ionic liquids in inducing stereoselectivity of the Michael addition of cyclohexanone with trans-β-nitrostyrene.

    PubMed

    Sun, Hui; Zhang, Dongju

    2011-03-01

    Density functional theory calculations have been carried out to elucidate the stereoselectivity of the Michael addition of cyclohexanone with trans-β-nitrostyrene, induced by a chiral ionic liquid (CIL) pyrrolidine-imidazolium bromide. By comparison of the C-C bond forming processes in the absence and presence of Br(-) anion, we found that intermolecular H-bonds between the imidazolium cation and the nitro group of trans-β-nitrostyrene and the steric hindrance of the imidazolium cation moiety on the Si-face of enamine dominate the stereoselectivity of the Michael addition. The presence of Br(-) anion obviously reduces the barrier by increasing the polarity of the C4=C5 bond of enamine. The theoretical results rationalize well the early experimental finding, and reveal a valuable clue for the further CIL design with high catalytic efficiency.

  7. Theoretical study on the asymmetric Michael addition of cyclohexanone with trans-beta-nitrostyrene catalyzed by a pyrrolidine-type chiral ionic liquid.

    PubMed

    Sun, Hui; Zhang, Dongju; Zhang, Changqiao; Liu, Chengbu

    2010-10-01

    The Michael addition of cyclohexanone with trans-beta-nitrostyrene catalyzed by a chiral ionic liquid (CIL) pyrrolidine-imidazolium bromide, which represents a prototype of CIL-promoted asymmetric syntheses, has been investigated by performing density functional theory calculations. We show the details of the mechanism and energetics, the influence of the acid additive on the reactivity, and the functional role of the CIL in the asymmetric addition. It is found that the reaction proceeds via two stages, i.e., the initial enamine formation, where the imine complex is first created and then isomerizes into the enamine intermediate, and the subsequent Michael addition involving a three-step mechanism. The calculations show that the presence of the acid additive changes the imine formation mechanism and lowers the reaction barrier, as well as, more importantly, makes the reaction become highly thermodynamically favored. It is also suggested that both the anion and cation of the CIL synergically facilitate the reaction, which act as the proton acceptor in the imine-enamine tautomerism and the stabilizer of the negative charge in the C-C bond formation process, respectively. The present theoretical study rationalizes the early experimental findings well and provides aid to some extent for the rational design of efficient CIL catalysts.

  8. The heat dissipation model and desensitizing mechanism of the HMX/additive interfaces: a theoretical investigation based on linear response theory

    NASA Astrophysics Data System (ADS)

    Long, Yao; Chen, Jun

    2013-07-01

    Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) is a high-energy explosive with high sensitivity. The heat dissipation of the HMX/additive interface is a key issue in understanding the hot spot formation and desensitizing mechanism of mixture explosive. In this work, we derive new formulae to calculate the heat dissipation rate for a set of HMX/additive interfaces, and build a physical model to describe the energy dissipation time and distance in mixture explosive. Four kinds of additives are considered: 1,3,5-triamino-2,4,6-trinitrobenzene, graphite, paraffin and fluoropolymers. At low strength loading, we prove that the heat dissipation rate is proportional to the square of frequency, and suggest a way to decrease the sensitivity of the explosive. At medium strength loading, the viscosity coefficient and friction coefficient of interface are calculated. The desensitizing abilities of additives to HMX are discussed systematically.

  9. Responses to a theoretically adapted clinical trial education session: faith-based sites versus rural work site dissemination.

    PubMed

    Aumiller, Betsy B; Parrott, Roxanne; Lengerich, Eugene J; Dominic, Oralia; Camacho, Fabian; Lehman, Eric; Gallant, Nancy R; Loughran, Thomas P

    2013-12-01

    The process for advancing biomedical knowledge depends upon recruiting an adequate and representative sample of individuals to voluntarily participate in research studies. A consistent personal barrier to cancer clinical trial participation is the lack of awareness and understanding related to trial availability, and the prevention and treatment roles participation represents. In particular, comprehensive community-based approaches to recruit and educate rural residents are needed. Moreover, consistent under representation of priority populations should be addressed with innovative outreach to collaborate in identifying culturally meaningful approaches. A theoretically adapted version of a component of the National Cancer Institute's "Clinical Trial Education Series" was assessed via educational sessions delivered through work sites and churches. From eight focus groups with 90 participants, we found that church leaders, congregants, and community members were receptive to education on cancer research, increased their short-term knowledge about it, and intent to participate in cancer studies, decreased their current anxiety about clinical trials participation, and provided specific suggestions for further adapting the educational session to be even more culturally relevant. These outcomes provide evidence to support the effectiveness of future customized recruitment strategies embedded within a community or faith-based environment that may increase knowledge, decrease anxiety and intent to actual participation in cancer studies, as well as impact study representativeness and address causes of health disparities.

  10. Collective Commitment and Collective Efficacy: A Theoretical Model for Understanding the Motivational Dynamics of Dilemma Resolution in Inter-Professional Work

    ERIC Educational Resources Information Center

    Rose, Jo; Norwich, Brahm

    2014-01-01

    This paper presents a new theoretical model which conceptualizes inter-professional and multi-agency collaborative working, at the level of the individual within a group. This arises from a review of the literature around joint working, and is based on social psychological theories which refer to shared goals. The model assumes that collective…

  11. Methyl iodide oxidative addition to [Rh(acac)(CO)(PPh3)]: an experimental and theoretical study of the stereochemistry of the products and the reaction mechanism.

    PubMed

    Conradie, Marrigje M; Conradie, Jeanet

    2011-08-28

    Density functional theory was used to investigate the oxidative addition and subsequent carbonyl insertion and deinsertion steps of the reaction of methyl iodide to a rhodium(I) acetylacetonato complex of the formula [Rh(acac)(CO)(PPh(3))] (Hacac = acetylacetone). This process has been studied experimentally for many rhodium β-diketonato complexes, but, to the best of our knowledge, this is the first systematic computational study of the complete reaction sequence. Experimental (1)H techniques complement the theoretical results on the stereochemistry of the reaction intermediates and products. (1)H NMR also revealed the existence of a second rhodium(III)-acyl product, which has not been previously observed in this reaction. The calculated Gibbs free energy of activation of the oxidative addition reaction is 71 kJ mol(-1), which is in agreement with the experimental value of 82(1) kJ mol(-1). The DFT-calculated oxidative addition corresponds to an associative S(N)2 nucleophilic attack by the rhodium metal centre on the methyl iodide, which is in agreement with calculated and experimental (in brackets) activation parameters of the reaction, 27 (38.8) kJ mol(-1) for ΔH((≠)) and -147 (-146) J K(-1) mol(-1) for ΔS((≠)). PMID:21761056

  12. A theoretical and experimental study of additive effects of physical aging and antiplasticization on the water permeability of polymer film coatings.

    PubMed

    Guo, J H

    1994-03-01

    The effects of physical aging and antiplasticization on the water transport properties of glassy cellulose acetate film-coated tablets were investigated. The gradual approach toward thermodynamic equilibrium during physical aging decrease the free volume of the polymers. This decrease in free volume is accompanied by a decrease in the transport mobility, with concomitant changes in those properties of the polymer that depend on it. Antiplasticization arises from an interaction between the polymer and the plasticizer molecules and decreases the molecular mobility of the polymer and plasticizer. This effect was confirmed by mechanical measurements of polymer free films at the same experimental temperature. We have studied the additive effect of aging and antiplasticizing to see if the individual effects would interfere with one another, as might be expected if the same free volume were involved in each. The pronouncedly additive effects of physical aging and antiplasticization on the water permeability can be found in cellulose acetate film-coated tablets that were affected by longer physical aging time and lower plasticizer concentration. A theoretical study suggested that the free volume in the glassy polymer should consist of at least two independent parts, one of which is affected by annealing and the other by antiplasticization.

  13. The work of the European Union Reference Laboratory for Food Additives (EURL) and its support for the authorisation process of feed additives in the European Union: a review

    PubMed Central

    von Holst, Christoph; Robouch, Piotr; Bellorini, Stefano; de la Huebra, María José González; Ezerskis, Zigmas

    2016-01-01

    ABSTRACT This paper describes the operation of the European Union Reference Laboratory for Feed Additives (EURL) and its role in the authorisation procedure of feed additives in the European Union. Feed additives are authorised according to Regulation (EC) No. 1831/2003, which introduced a completely revised authorisation procedure and also established the EURL. The regulations authorising feed additives contain conditions of use such as legal limits of the feed additives, which require the availability of a suitable method of analysis for official control purposes under real world conditions. It is the task of the EURL to evaluate the suitability of analytical methods as proposed by the industry for this purpose. Moreover, the paper shows that one of the major challenges is the huge variety of the methodology applied in feed additive analysis, thus requiring expertise in quite different analytical areas. In order to cope with this challenge, the EURL is supported by a network of national reference laboratories (NRLs) and only the merged knowledge of all NRLs allows for a scientifically sound assessment of the analytical methods. PMID:26540604

  14. Effect of solvent and additives on the open-circuit voltage of ZnO-based dye-sensitized solar cells: a combined theoretical and experimental study.

    PubMed

    Le Bahers, Tangui; Labat, Frédéric; Pauporté, Thierry; Ciofini, Ilaria

    2010-11-28

    We have investigated the role of electrolyte composition, in terms of solvent and additive, on the open-circuit voltage (V(oc)) of ZnO-based dye-sensitized solar cells (DSSCs) using a combined experimental and theoretical approach. Calculations based on density functional theory (DFT) have been performed in order to describe the geometries and adsorption energies of various adsorbed solvents (nitromethane, acetonitrile and dimethylformamide) and p-tert-butylpyridine (TBP) (modeled by methylpyridine) on the ZnO (100) surface using a periodic approach. The densities of states (DOS) have been calculated and the energy position of the conduction band edge (CBE) has been evaluated for the different molecules adsorbed. The effect of the electrolyte composition on the standard redox potential of the iodide/triiodide redox couple has been experimentally determined. These two data values (CBE and standard redox potential) allowed us to determine the dependence of V(oc) on the electrolyte composition. The variations determined using this method were in good agreement with the measured V(oc) for cells made of electrodeposited ZnO films sensitized using D149 (indoline) dye. As in the case of TiO(2)-based cells, a correlation of V(oc) with the donor number of the adsorbed species was found. The present study clearly points out that both the CBE energy and the redox potential variation are important for explaining the experimentally observed changes in the V(oc) of DSSCs. PMID:20949189

  15. Experimental and Theoretical Analysis of Nanotransport in Oligophenylene Dithiol Junctions as a Function of Molecular Length and Contact Work Function.

    PubMed

    Xie, Zuoti; Bâldea, Ioan; Smith, Christopher E; Wu, Yanfei; Frisbie, C Daniel

    2015-08-25

    We report the results of an extensive investigation of metal-molecule-metal tunnel junctions based on oligophenylene dithiols (OPDs) bound to several types of electrodes (M1-S-(C6H4)n-S-M2, with 1 ≤ n ≤ 4 and M1,2 = Ag, Au, Pt) to examine the impact of molecular length (n) and metal work function (Φ) on junction properties. Our investigation includes (1) measurements by scanning Kelvin probe microscopy of electrode work function changes (ΔΦ = ΦSAM - Φ) caused by chemisorption of OPD self-assembled monolayers (SAMs), (2) measurements of junction current-voltage (I-V) characteristics by conducting probe atomic force microscopy in the linear and nonlinear bias ranges, and (3) direct quantitative analysis of the full I-V curves. Further, we employ transition voltage spectroscopy (TVS) to estimate the energetic alignment εh = EF - EHOMO of the dominant molecular orbital (HOMO) relative to the Fermi energy EF of the junction. Where photoelectron spectroscopy data are available, the εh values agree very well with those determined by TVS. Using a single-level model, which we justify via ab initio quantum chemical calculations at post-density functional theory level and additional UV-visible absorption measurements, we are able to quantitatively reproduce the I-V measurements in the whole bias range investigated (∼1.0-1.5 V) and to understand the behavior of εh and Γ (contact coupling strength) extracted from experiment. We find that Fermi level pinning induced by the strong dipole of the metal-S bond causes a significant shift of the HOMO energy of an adsorbed molecule, resulting in εh exhibiting a weak dependence with the work function Φ. Both of these parameters play a key role in determining the tunneling attenuation factor (β) and junction resistance (R). Correlation among Φ, ΔΦ, R, transition voltage (Vt), and εh and accurate simulation provide a remarkably complete picture of tunneling transport in these prototypical molecular junctions.

  16. Can Religious Expression and Sexual Orientation Affirmation Coexist in Social Work? A Critique of Hodge's Theoretical, Theological, and Conceptual Frameworks

    ERIC Educational Resources Information Center

    Dessel, Adrienne; Bolen, Rebecca; Shepardson, Christine

    2011-01-01

    Social work strives to be inclusive of all cultural groups and religious identities. However, a tension exists in the profession between freedom of religious expression and full acceptance of lesbian, gay, and bisexual people. David Hodge and others claim social work is oppressive to evangelical Christians. This article critiques primarily Hodge's…

  17. An Approach to Life Skills Group Work with Youth in Transition to Independent Living: Theoretical, Practice, and Operational Considerations

    ERIC Educational Resources Information Center

    Allen, Terrence T.; Williams, Larry D.

    2012-01-01

    Group work is fundamental to working with youth learning about independent living and in making the tough and challenging transition to independence. The authors, seasoned and experienced group workers and researchers with youth leaving the child welfare system, will present a conceptual framework and set of practices for helping youth gain those…

  18. Supporting the Work Arrangements of Cooperating Teachers and University Supervisors to Better Train Preservice Teachers: A New Theoretical Contribution

    ERIC Educational Resources Information Center

    Escalié, Guillaume; Chaliès, Sébastien

    2016-01-01

    This longitudinal case study examines whether a school-based training scheme that brings together different categories of teacher educators (university supervisors and cooperating teachers) engenders true collective training activity and, if so, whether this collective work contributes to pre-service teacher education. The scheme grew out of a…

  19. Photoinduced work function changes by isomerization of a densely packed azobenzene-based SAM on Au: a joint experimental and theoretical study.

    PubMed

    Crivillers, N; Liscio, A; Di Stasio, F; Van Dyck, C; Osella, S; Cornil, D; Mian, S; Lazzerini, G M; Fenwick, O; Orgiu, E; Reinders, F; Braun, S; Fahlman, M; Mayor, M; Cornil, J; Palermo, V; Cacialli, F; Samorì, P

    2011-08-28

    Responsive monolayers are key building blocks for future applications in organic and molecular electronics in particular because they hold potential for tuning the physico-chemical properties of interfaces, including their energetics. Here we study a photochromic SAM based on a conjugated azobenzene derivative and its influence on the gold work function (Φ(Au)) when chemisorbed on its surface. In particular we show that the Φ(Au) can be modulated with external stimuli by controlling the azobenzene trans/cis isomerization process. This phenomenon is characterized experimentally by four different techniques, kelvin probe, kelvin probe force microscopy, electroabsorption spectroscopy and ultraviolet photoelectron spectroscopy. The use of different techniques implies exposing the SAM to different measurement conditions and different preparation methods, which, remarkably, do not alter the observed work function change (Φ(trans)-Φ(cis)). Theoretical calculations provided a complementary insight crucial to attain a deeper knowledge on the origin of the work function photo-modulation.

  20. Central additive effect of Ginkgo biloba and Rhodiola rosea on psychomotor vigilance task and short-term working memory accuracy

    PubMed Central

    Al-Kuraishy, Hayder M.

    2016-01-01

    Aim: The present study investigates the effect of combined treatment with Ginkgo biloba and/or Rhodiola rosea on psychomotor vigilance task (PVT) and short-term working memory accuracy. Subjects and Methods: A total number of 112 volunteers were enrolled to study the effect of G. biloba and R. rosea on PVT and short-term working memory accuracy as compared to placebo effects, the central cognitive effect was assessed by critical flicker-fusion frequency, PVT, and computerized N-back test. Results: Placebo produced no significant effects on all neurocognitive tests measure P > 0.05 in normal healthy volunteers, G. biloba or R. rosea improve PVT and low to moderate working memory accuracy, The combined effect of R. rosea and G. biloba leading to more significant effect on PVT, all levels of short-term working memory accuracy and critical fusion versus flicker P < 0.01, more than of G. biloba or R. rosea when they used alone. Conclusion: The combined effect of R. rosea and G. biloba leading to a more significant effect on cognitive function than either G. biloba or R. rosea when they used alone. PMID:27069717

  1. The Contribution of Work and Family Roles to Mental Health: An Evaluation of Additive and Interactive Models.

    ERIC Educational Resources Information Center

    Repetti, Rena L.

    Rather than ask whether multiple roles, such as employee, wife, and mother, have a protective or harmful effect on women's psychological well being, this study examined the combination of stressors and supports associated with work and family roles. Female clerical workers (N=44) who were married and/or had a child living at home completed…

  2. Theoretical and Experimental Investigation of Thermodynamics and Kinetics of Thiol-Michael Addition Reactions: A Case Study of Reversible Fluorescent Probes for Glutathione Imaging in Single Cells.

    PubMed

    Chen, Jianwei; Jiang, Xiqian; Carroll, Shaina L; Huang, Jia; Wang, Jin

    2015-12-18

    Density functional theory (DFT) was applied to study the thermodynamics and kinetics of reversible thiol-Michael addition reactions. M06-2X/6-31G(d) with the SMD solvation model can reliably predict the Gibbs free energy changes (ΔG) of thiol-Michael addition reactions with an error of less than 1 kcal·mol(-1) compared with the experimental benchmarks. Taking advantage of this computational model, the first reversible reaction-based fluorescent probe was developed that can monitor the changes in glutathione levels in single living cells.

  3. Efficacy of cognitive rehabilitation therapies for mild cognitive impairment (MCI) in older adults: Working toward a theoretical model and evidence-based interventions

    PubMed Central

    Huckans, Marilyn; Hutson, Lee; Twamley, Elizabeth; Jak, Amy; Kaye, Jeffrey; Storzbach, Daniel

    2013-01-01

    Objective To evaluate the efficacy of cognitive rehabilitation therapies (CRTs) for mild cognitive impairment (MCI). Our review revealed a need for evidence-based treatments for MCI and a lack of a theoretical rehabilitation model to guide the development and evaluation of these interventions. We have thus proposed a theoretical rehabilitation model of MCI that yields key intervention targets - cognitive compromise, functional compromise, neuropsychiatric symptoms, and modifiable risk and protective factors known to be associated with MCI and dementia. Our model additionally defines specific cognitive rehabilitation approaches that may directly or indirectly target key outcomes - restorative cognitive training, compensatory cognitive training, lifestyle interventions, and psychotherapeutic techniques. Methods Fourteen randomized controlled trials met inclusion criteria and were reviewed. Results Studies markedly varied in terms of intervention approaches and selected outcome measures and were frequently hampered by design limitations. The bulk of the evidence suggested that CRTs can change targeted behaviors in individuals with MCI and that CRTs are associated with improvements in objective cognitive performance, but the pattern of effects on specific cognitive domains was inconsistent across studies. Other important outcomes (i.e., daily functioning, quality of life, neuropsychiatric symptom severity) were infrequently assessed across studies. Few studies evaluated long-term outcomes or the impact of CRTs on conversion rates from MCI to dementia or normal cognition. Conclusions Overall, results from trials are promising but inconclusive. Additional well-designed and adequately powered trials are warranted and required before CRTs for MCI can be considered evidence based. PMID:23471631

  4. Low-temperature mechanisms for the formation of substituted azanaphthalenes through consecutive CN and C2H additions to styrene and N-methylenebenzenamine: a theoretical study.

    PubMed

    Landera, Alexander; Mebel, Alexander M

    2013-05-15

    Ab initio G3(MP2,CC)/B3LYP/6-311G** calculations of potential energy surfaces (PESs) for the reactions of cyano and ethynyl radicals with styrene and N-methylenebenzenamine have been performed to investigate a possible formation mechanism of the prototype nitrogen-containing polycyclic aromatic compounds: (substituted) 1- and 2-azanaphthalenes. The computed PESs and molecular parameters have been used for RRKM and RRKM-Master Equation calculations of reaction rate constants and product branching ratios under single-collision conditions and at pressures from 3 to 10(-6) mbar and temperatures of 90-200 K relevant to the organic aerosol formation regions in the stratosphere of a Saturn's moon Titan. The results show that ethynyl-substituted 1- and 2-azanaphthalenes can be produced by consecutive CN and C2H additions to styrene or by two C2H additions to N-methylenebenzenamine. All CN and C2H radical addition complexes are formed in the entrance channels without barriers, and the reactions are computed to be exothermic, with all intermediates and transition states along the favorable pathways residing lower in energy than the respective initial reactants. The reactions are completed by dissociation of chemically activated radical intermediates via H losses, so that collisional stabilization of the intermediates is not required to form the final products. These features make the proposed mechanism viable even at very low temperatures and under single-collision conditions and especially significant for astrochemical environments. In Titan's stratosphere, collisional stabilization of the initial CN + styrene reaction adducts may be significant, but substantial amounts of 2-vinylbenzonitrile and 2-ethynyl-N-methylenebenzenamine can still be produced and then react with C2H to form substituted azanaphthalenes.

  5. Tuning of the Electronic Properties of Armchair Graphene Nanoribbons through Functionalization: Theoretical Study of (1)Δg O2 Border Addition.

    PubMed

    Ghigo, Giovanni; Maranzana, Andrea; Tonachini, Glauco

    2015-10-01

    We report the results of a DFT study of the border oxidation by (1) Δg O2 of molecular models of armchair graphene nanoribbons (a-GNRs). The aim of this work is to propose a new method, as an alternative or complementary method to the tuning of the size, to modify the electronic properties of a-GNRs. Here, we investigate modification of the HOMO and LUMO energies, which are some of the most important parameters to be controlled in the design of organic electronic devices. We study the oxidation reaction mechanism of medium-size polycyclic aromatic hydrocarbons, mimicking the stiffness and reactivity of a-GNRs. Thermodynamics and kinetics indicate that the reaction should bring about a decoration of the borders with vicinal dialdehyde groups. We also study the effect of this oxidation on the HOMO and LUMO energies of two series of molecular models of a-GNRs with increasing lengths. The results suggest that the oxidized a-GNRs should present LUMO energies lowered by 0.3-0.5 eV with respect to the original material, whereas the HOMO energies are barely lowered.

  6. The influence of Ag+Mg additions on the nucleation of strengthening precipitates in a non-cold-worked Al-Cu-Li alloy

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Aluminum-copper-lithium alloys generally require cold work to attain their highest strengths in artificially aged tempers. These alloys are usually strengthened by a combination of the metastable delta prime (Al3Li) and theta prime (Al2Cu) phases and the equilibrium T sub 1 (Al2CuLi) phase, and where the T sub 1 phase is a more potent strengthener than the delta prime. Various investigators have shown that the high strengths obtained after artificial aging associated with cold work result from the heterogeneous precipitation of T sub 1 on matrix dislocations. The objective here is to elucidate the mechanism by which the Ag+Mg additions stimulate the precipitation of T sub 1 type precipitates without cold work. To accomplish this, the microstructure of an Al-6.3Cu-1.3Li-0.14Zr model alloy was evaluated in a T6 type temper with and without the Ag+Mg addition.

  7. Development of a systems theoretical procedure for evaluation of the work organization of the cockpit crew of a civil transport airplane

    NASA Technical Reports Server (NTRS)

    Fricke, M.; Vees, C.

    1983-01-01

    To achieve optimum design for the man machine interface with aircraft, a description of the interaction and work organization of the cockpit crew is needed. The development of system procedure to evaluate the work organization of pilots while structuring the work process is examined. Statistical data are needed to simulate sequences of pilot actions on the computer. Investigations of computer simulation and applicability for evaluation of crew concepts are discussed.

  8. [A need to implement new tools for diagnosing tobacco-addition syndrome and readiness/motivation to quit smoking in the working-age population in Poland].

    PubMed

    Broszkiewicz, Marzenna; Drygas, Wojciech

    2016-01-01

    High rates of tobacco use is still observed in working-age population in Poland. The present level of the state tobacco control has been achieved through adopting legal regulations and population-based interventions. In Poland a sufficient contribution of health professionals to the diagnosis of the tobacco-addition syndrome (TAS) and the application of the 5A's (ask, advice, assess, assist, arrange follow-up) brief intervention, has not been confirmed by explicit research results. Systemic solutions of the health care system of the professional control, specialist health care, health professional trainings and reference centres have not as yet been elaborated. The tools for diagnosing tobacco dependence and motivation to quit smoking, developed over 30 years ago and recommended by experts to be used in clinical and research practice, have not met the current addiction criteria. In this paper other tools than those previously recommended - tests developed in the first decade of the 21st century (including Cigarette Dependence Scale and Nicotine Dependence Syndrome Scale), reflecting modern concepts of nicotine dependence are presented. In the literature on the readiness/motivation to change health behaviors, a new approach dominates. The motivational interviewing (MI) by Miller and Rollnick concentrates on a smoking person and his or her internal motivation. Motivational interviewing is recommended by the World Health Organization as a 5R's (relevance, risks, rewards, roadblocks, repetition) brief motivational advice, addressed to tobacco users who are unwilling to make a quit attempt. In Poland new research studies on the implementation of new diagnostic tools and updating of binding guidelines should be undertaken, to strengthen primary health care in treating tobacco dependence, and to incorporate MI and 5R's into trainings in TAS diagnosing and treating addressed to health professionals. PMID:27044722

  9. [A need to implement new tools for diagnosing tobacco-addition syndrome and readiness/motivation to quit smoking in the working-age population in Poland].

    PubMed

    Broszkiewicz, Marzenna; Drygas, Wojciech

    2016-01-01

    High rates of tobacco use is still observed in working-age population in Poland. The present level of the state tobacco control has been achieved through adopting legal regulations and population-based interventions. In Poland a sufficient contribution of health professionals to the diagnosis of the tobacco-addition syndrome (TAS) and the application of the 5A's (ask, advice, assess, assist, arrange follow-up) brief intervention, has not been confirmed by explicit research results. Systemic solutions of the health care system of the professional control, specialist health care, health professional trainings and reference centres have not as yet been elaborated. The tools for diagnosing tobacco dependence and motivation to quit smoking, developed over 30 years ago and recommended by experts to be used in clinical and research practice, have not met the current addiction criteria. In this paper other tools than those previously recommended - tests developed in the first decade of the 21st century (including Cigarette Dependence Scale and Nicotine Dependence Syndrome Scale), reflecting modern concepts of nicotine dependence are presented. In the literature on the readiness/motivation to change health behaviors, a new approach dominates. The motivational interviewing (MI) by Miller and Rollnick concentrates on a smoking person and his or her internal motivation. Motivational interviewing is recommended by the World Health Organization as a 5R's (relevance, risks, rewards, roadblocks, repetition) brief motivational advice, addressed to tobacco users who are unwilling to make a quit attempt. In Poland new research studies on the implementation of new diagnostic tools and updating of binding guidelines should be undertaken, to strengthen primary health care in treating tobacco dependence, and to incorporate MI and 5R's into trainings in TAS diagnosing and treating addressed to health professionals.

  10. 43 CFR 3207.12 - What work am I required to perform each year for BLM to continue the initial and additional...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... year for BLM to continue the initial and additional extensions of the primary term of my lease? 3207.12... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) GEOTHERMAL RESOURCE LEASING Lease Terms and... additional extensions of the primary term of my lease? (a) To continue the initial extension of the...

  11. 43 CFR 3207.12 - What work am I required to perform each year for BLM to continue the initial and additional...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... year for BLM to continue the initial and additional extensions of the primary term of my lease? 3207.12... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) GEOTHERMAL RESOURCE LEASING Lease Terms and... additional extensions of the primary term of my lease? (a) To continue the initial extension of the...

  12. 43 CFR 3207.12 - What work am I required to perform each year for BLM to continue the initial and additional...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... year for BLM to continue the initial and additional extensions of the primary term of my lease? 3207.12... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) GEOTHERMAL RESOURCE LEASING Lease Terms and... additional extensions of the primary term of my lease? (a) To continue the initial extension of the...

  13. 43 CFR 3207.12 - What work am I required to perform each year for BLM to continue the initial and additional...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... year for BLM to continue the initial and additional extensions of the primary term of my lease? 3207.12... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) GEOTHERMAL RESOURCE LEASING Lease Terms and... additional extensions of the primary term of my lease? (a) To continue the initial extension of the...

  14. [How can the patient's home be changed into a work place for the nurse? Interaction theoretical note on the role of the professional nurse in ambulatory care].

    PubMed

    Wiese, M

    1995-09-01

    In home-care-situations nurses are confronted with the special problem of changing the house of the patients into a nurse's place of work and to play at this "stage" the role of professional nurses. The role-theory of Goffman is the background to outline some structural barriers for the performance of this role. In such and other care-giving-situations the nurse must be able to keep a necessary amount of role-distance, to regain professional autonomy.

  15. A review of the work of the EU Reference Laboratory supporting the authorisation process of feed additives in the EU. [corrected].

    PubMed

    von Holst, Christoph; Robouch, Piotr; Bellorini, Stefano; González de la Huebra, María José; Ezerskis, Zigmas

    2016-01-01

    This paper describes the operation of the European Union Reference Laboratory for Feed Additives (EURL) and its role in the authorisation procedure of feed additives in the European Union. Feed additives are authorised according to Regulation (EC) No. 1831/2003, which introduced a completely revised authorisation procedure and also established the EURL. The regulations authorising feed additives contain conditions of use such as legal limits of the feed additives, which require the availability of a suitable method of analysis for official control purposes under real world conditions. It is the task of the EURL to evaluate the suitability of analytical methods as proposed by the industry for this purpose. Moreover, the paper shows that one of the major challenges is the huge variety of the methodology applied in feed additive analysis, thus requiring expertise in quite different analytical areas. In order to cope with this challenge, the EURL is supported by a network of national reference laboratories (NRLs) and only the merged knowledge of all NRLs allows for a scientifically sound assessment of the analytical methods.

  16. Theoretical Issues

    SciTech Connect

    Marc Vanderhaeghen

    2007-04-01

    The theoretical issues in the interpretation of the precision measurements of the nucleon-to-Delta transition by means of electromagnetic probes are highlighted. The results of these measurements are confronted with the state-of-the-art calculations based on chiral effective-field theories (EFT), lattice QCD, large-Nc relations, perturbative QCD, and QCD-inspired models. The link of the nucleon-to-Delta form factors to generalized parton distributions (GPDs) is also discussed.

  17. Theoretical geology

    NASA Astrophysics Data System (ADS)

    Mikeš, Daniel

    2010-05-01

    Theoretical geology Present day geology is mostly empirical of nature. I claim that geology is by nature complex and that the empirical approach is bound to fail. Let's consider the input to be the set of ambient conditions and the output to be the sedimentary rock record. I claim that the output can only be deduced from the input if the relation from input to output be known. The fundamental question is therefore the following: Can one predict the output from the input or can one predict the behaviour of a sedimentary system? If one can, than the empirical/deductive method has changes, if one can't than that method is bound to fail. The fundamental problem to solve is therefore the following: How to predict the behaviour of a sedimentary system? It is interesting to observe that this question is never asked and many a study is conducted by the empirical/deductive method; it seems that the empirical method has been accepted as being appropriate without question. It is, however, easy to argument that a sedimentary system is by nature complex and that several input parameters vary at the same time and that they can create similar output in the rock record. It follows trivially from these first principles that in such a case the deductive solution cannot be unique. At the same time several geological methods depart precisely from the assumption, that one particular variable is the dictator/driver and that the others are constant, even though the data do not support such an assumption. The method of "sequence stratigraphy" is a typical example of such a dogma. It can be easily argued that all the interpretation resulting from a method that is built on uncertain or wrong assumptions is erroneous. Still, this method has survived for many years, nonwithstanding all the critics it has received. This is just one example of the present day geological world and is not unique. Even the alternative methods criticising sequence stratigraphy actually depart from the same

  18. Review of ASME code criteria for control of primary loads on nuclear piping system branch connections and recommendations for additional development work

    SciTech Connect

    Rodabaugh, E.C.; Gwaltney, R.C.; Moore, S.E.

    1993-11-01

    This report collects and uses available data to reexamine the criteria for controlling primary loads in nuclear piping branch connections as expressed in Section III of the ASME Boiler and Pressure Vessel Code. In particular, the primary load stress indices given in NB-3650 and NB-3683 are reexamined. The report concludes that the present usage of the stress indices in the criteria equations should be continued. However, the complex treatment of combined branch and run moments is not supported by available information. Therefore, it is recommended that this combined loading evaluation procedure be replaced for primary loads by the separate leg evaluation procedure specified in NC/ND-3653.3(c) and NC/ND-3653.3(d). No recommendation is made for fatigue or secondary load evaluations for Class 1 piping. Further work should be done on the development of better criteria for treatment of combined branch and run moment effects.

  19. Theoretical Astrophysics at Fermilab

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Theoretical Astrophysics Group works on a broad range of topics ranging from string theory to data analysis in the Sloan Digital Sky Survey. The group is motivated by the belief that a deep understanding of fundamental physics is necessary to explain a wide variety of phenomena in the universe. During the three years 2001-2003 of our previous NASA grant, over 120 papers were written; ten of our postdocs went on to faculty positions; and we hosted or organized many workshops and conferences. Kolb and collaborators focused on the early universe, in particular and models and ramifications of the theory of inflation. They also studied models with extra dimensions, new types of dark matter, and the second order effects of super-horizon perturbations. S tebbins, Frieman, Hui, and Dodelson worked on phenomenological cosmology, extracting cosmological constraints from surveys such as the Sloan Digital Sky Survey. They also worked on theoretical topics such as weak lensing, reionization, and dark energy. This work has proved important to a number of experimental groups [including those at Fermilab] planning future observations. In general, the work of the Theoretical Astrophysics Group has served as a catalyst for experimental projects at Fennilab. An example of this is the Joint Dark Energy Mission. Fennilab is now a member of SNAP, and much of the work done here is by people formerly working on the accelerator. We have created an environment where many of these people made transition from physics to astronomy. We also worked on many other topics related to NASA s focus: cosmic rays, dark matter, the Sunyaev-Zel dovich effect, the galaxy distribution in the universe, and the Lyman alpha forest. The group organized and hosted a number of conferences and workshop over the years covered by the grant. Among them were:

  20. Solving the Big Data (BD) Problem in Advanced Manufacturing (Subcategory for work done at Georgia Tech. Study Process and Design Factors for Additive Manufacturing Improvement)

    SciTech Connect

    Clark, Brett W.; Diaz, Kimberly A.; Ochiobi, Chinaza Darlene; Paynabar, Kamran

    2015-09-01

    3D printing originally known as additive manufacturing is a process of making 3 dimensional solid objects from a CAD file. This ground breaking technology is widely used for industrial and biomedical purposes such as building objects, tools, body parts and cosmetics. An important benefit of 3D printing is the cost reduction and manufacturing flexibility; complex parts are built at the fraction of the price. However, layer by layer printing of complex shapes adds error due to the surface roughness. Any such error results in poor quality products with inaccurate dimensions. The main purpose of this research is to measure the amount of printing errors for parts with different geometric shapes and to analyze them for finding optimal printing settings to minimize the error. We use a Design of Experiments framework, and focus on studying parts with cone and ellipsoid shapes. We found that the orientation and the shape of geometric shapes have significant effect on the printing error. From our analysis, we also determined the optimal orientation that gives the least printing error.

  1. Food additives

    PubMed Central

    Spencer, Michael

    1974-01-01

    Food additives are discussed from the food technology point of view. The reasons for their use are summarized: (1) to protect food from chemical and microbiological attack; (2) to even out seasonal supplies; (3) to improve their eating quality; (4) to improve their nutritional value. The various types of food additives are considered, e.g. colours, flavours, emulsifiers, bread and flour additives, preservatives, and nutritional additives. The paper concludes with consideration of those circumstances in which the use of additives is (a) justified and (b) unjustified. PMID:4467857

  2. Addition of one and two units of C2H to styrene: A theoretical study of the C10H9 and C12H9 systems and implications toward growth of polycyclic aromatic hydrocarbons at low temperatures

    NASA Astrophysics Data System (ADS)

    Landera, Alexander; Kaiser, Ralf I.; Mebel, Alexander M.

    2011-01-01

    Various mechanisms of the formation of naphthalene and its substituted derivatives have been investigated by ab initio G3(MP2,CC)/B3LYP/6-311G** calculations of potential energy surfaces for the reactions of one and two C2H additions to styrene combined with RRKM calculations of product branching ratios under single-collision conditions. The results show that for the C2H + styrene reaction, the dominant routes are H atom eliminations from the initial adducts; C2H addition to the vinyl side chain of styrene is predicted to produce trans or cis conformations of phenylvinylacetylene (t- and c-PVA), whereas C2H addition to the ortho carbon in the ring is expected to lead to the formation of o-ethynylstyrene. Although various reaction channels may lead to a second ring closure and the formation of naphthalene, they are not competitive with the direct H loss channels producing PVAs and ethynylstyrenes. However, c-PVA and o-ethynylstyrene may undergo a second addition of the ethynyl radical to ultimately produce substituted naphthalene derivatives. α- and β-additions of C2H to the side chain in c-PVA are calculated to form 2-ethynyl-naphthalene with branching ratios of about 30% and 96%, respectively; the major product in the case of α-addition would be cis-1-hexene-3,5-diynyl-benzene produced by an immediate H elimination from the initial adduct. C2H addition to the ethynyl side chain in o-ethynylstyrene is predicted to lead to the formation of 1-ethynyl-naphthalene as the dominant product. The C2H + styrene → t-PVA + H/c-PVA + H/ o-ethynylstyrene, C2H + c-PVA → 2-ethynyl-naphthalene + H, and C2H + o-ethynylstyrene → 1-ethynyl-naphthalene + H reactions are calculated to occur without a barrier and with high exothermicity, with all intermediates, transition states, and products lying significantly lower in energy than the initial reactants, and hence to be fast even at very low temperature conditions prevailing in Titan's atmosphere or in the interstellar medium

  3. Rationale, design and methods of the Study of Work and Pain (SWAP): a cluster randomised controlled trial testing the addition of a vocational advice service to best current primary care for patients with musculoskeletal pain (ISRCTN 52269669)

    PubMed Central

    2014-01-01

    Background Musculoskeletal pain is a major contributor to short and long term work absence. Patients seek care from their general practitioner (GP) and yet GPs often feel ill-equipped to deal with work issues. Providing a vocational case management service in primary care, to support patients with musculoskeletal problems to remain at or return to work, is one potential solution but requires robust evaluation to test clinical and cost-effectiveness. Methods/Design This protocol describes a cluster randomised controlled trial, with linked qualitative interviews, to investigate the effect of introducing a vocational advice service into general practice, to provide a structured approach to managing work related issues in primary care patients with musculoskeletal pain who are absent from work or struggling to remain in work. General practices (n = 6) will be randomised to offer best current care or best current care plus a vocational advice service. Adults of working age who are absent from or struggling to remain in work due to a musculoskeletal pain problem will be invited to participate and 330 participants will be recruited. Data collection will be through patient completed questionnaires at baseline, 4 and 12 months. The primary outcome is self-reported work absence at 4 months. Incremental cost-utility analysis will be undertaken to calculate the cost per additional QALY gained and incremental net benefits. A linked interview study will explore the experiences of the vocational advice service from the perspectives of GPs, nurse practitioners (NPs), patients and vocational advisors. Discussion This paper presents the rationale, design, and methods of the Study of Work And Pain (SWAP) trial. The results of this trial will provide evidence to inform primary care practice and guide the development of services to provide support for musculoskeletal pain patients with work-related issues. Trial registration Current Controlled Trials ISRCTN52269669. PMID:25012813

  4. An assessment of silver copper sulfides for photovoltaic applications: theoretical and experimental insights† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6ta03376h Click here for additional data file. Click here for additional data file.

    PubMed Central

    Savory, Christopher N.; Ganose, Alex M.; Travis, Will; Atri, Ria S.; Palgrave, Robert G.

    2016-01-01

    As the worldwide demand for energy increases, low-cost solar cells are being looked to as a solution for the future. To attain this, non-toxic earth-abundant materials are crucial, however cell efficiencies for current materials are limited in many cases. In this article, we examine the two silver copper sulfides AgCuS and Ag3CuS2 as possible solar absorbers using hybrid density functional theory, diffuse reflectance spectroscopy, XPS and Hall effect measurements. We show that both compounds demonstrate promising electronic structures and band gaps for high theoretical efficiency solar cells, based on Shockley–Queisser limits. Detailed analysis of their optical properties, however, indicates that only AgCuS should be of interest for PV applications, with a high theoretical efficiency. From this, we also calculate the band alignment of AgCuS against various buffer layers to aid in future device construction. PMID:27774149

  5. Theoretical effect of modifications to the upper surface of two NACA airfoils using smooth polynomial additional thickness distributions which emphasize leading edge profile and which vary quadratically at the trailing edge. [using flow equations and a CDC 7600 computer

    NASA Technical Reports Server (NTRS)

    Merz, A. W.; Hague, D. S.

    1975-01-01

    An investigation was conducted on a CDC 7600 digital computer to determine the effects of additional thickness distributions to the upper surface of the NACA 64-206 and 64 sub 1 - 212 airfoils. The additional thickness distribution had the form of a continuous mathematical function which disappears at both the leading edge and the trailing edge. The function behaves as a polynomial of order epsilon sub 1 at the leading edge, and a polynomial of order epsilon sub 2 at the trailing edge. Epsilon sub 2 is a constant and epsilon sub 1 is varied over a range of practical interest. The magnitude of the additional thickness, y, is a second input parameter, and the effect of varying epsilon sub 1 and y on the aerodynamic performance of the airfoil was investigated. Results were obtained at a Mach number of 0.2 with an angle-of-attack of 6 degrees on the basic airfoils, and all calculations employ the full potential flow equations for two dimensional flow. The relaxation method of Jameson was employed for solution of the potential flow equations.

  6. Phosphazene additives

    DOEpatents

    Harrup, Mason K; Rollins, Harry W

    2013-11-26

    An additive comprising a phosphazene compound that has at least two reactive functional groups and at least one capping functional group bonded to phosphorus atoms of the phosphazene compound. One of the at least two reactive functional groups is configured to react with cellulose and the other of the at least two reactive functional groups is configured to react with a resin, such as an amine resin of a polycarboxylic acid resin. The at least one capping functional group is selected from the group consisting of a short chain ether group, an alkoxy group, or an aryloxy group. Also disclosed are an additive-resin admixture, a method of treating a wood product, and a wood product.

  7. Potlining Additives

    SciTech Connect

    Rudolf Keller

    2004-08-10

    In this project, a concept to improve the performance of aluminum production cells by introducing potlining additives was examined and tested. Boron oxide was added to cathode blocks, and titanium was dissolved in the metal pool; this resulted in the formation of titanium diboride and caused the molten aluminum to wet the carbonaceous cathode surface. Such wetting reportedly leads to operational improvements and extended cell life. In addition, boron oxide suppresses cyanide formation. This final report presents and discusses the results of this project. Substantial economic benefits for the practical implementation of the technology are projected, especially for modern cells with graphitized blocks. For example, with an energy savings of about 5% and an increase in pot life from 1500 to 2500 days, a cost savings of $ 0.023 per pound of aluminum produced is projected for a 200 kA pot.

  8. A theoretical framework for psychiatric nursing practice.

    PubMed

    Onega, L L

    1991-01-01

    Traditionally, specific theoretical frameworks which are congruent with psychiatric nursing practice have been poorly articulated. The purpose of this paper is to identify and discuss a philosophical base, a theoretical framework, application to psychiatric nursing, and issues related to psychiatric nursing knowledge development and practice. A philosophical framework that is likely to be congruent with psychiatric nursing, which is based on the nature of human beings, health, psychiatric nursing and reality, is identified. Aaron Antonovsky's Salutogenic Model is discussed and applied to psychiatric nursing. This model provides a helpful way for psychiatric nurses to organize their thinking processes and ultimately improve the health care services that they offer to their clients. Goal setting and nursing interventions using this model are discussed. Additionally, application of the use of Antonovsky's model is made to nursing research areas such as hardiness, uncertainty, suffering, empathy and literary works. Finally, specific issues related to psychiatric nursing are addressed.

  9. Theoretical Developments in SUSY

    NASA Astrophysics Data System (ADS)

    Shifman, M.

    2009-01-01

    I am proud that I was personally acquainted with Julius Wess. We first met in 1999 when I was working on the Yuri Golfand Memorial Volume (The Many Faces of the Superworld, World Scientific, Singapore, 2000). I invited him to contribute, and he accepted this invitation with enthusiasm. After that, we met many times, mostly at various conferences in Germany and elsewhere. I was lucky to discuss with Julius questions of theoretical physics, and hear his recollections on how supersymmetry was born. In physics Julius was a visionary, who paved the way to generations of followers. In everyday life he was a kind and modest person, always ready to extend a helping hand to people who were in need of his help. I remember him telling me how concerned he was about the fate of theoretical physicists in Eastern Europe after the demise of communism. His ties with Israeli physicists bore a special character. I am honored by the opportunity to contribute an article to the Julius Wess Memorial Volume. I will review theoretical developments of the recent years in non-perturbative supersymmetry.

  10. Theoretical Particle Astrophysics

    SciTech Connect

    Kamionkowski, Marc

    2013-08-07

    Abstract: Theoretical Particle Astrophysics The research carried out under this grant encompassed work on the early Universe, dark matter, and dark energy. We developed CMB probes for primordial baryon inhomogeneities, primordial non-Gaussianity, cosmic birefringence, gravitational lensing by density perturbations and gravitational waves, and departures from statistical isotropy. We studied the detectability of wiggles in the inflation potential in string-inspired inflation models. We studied novel dark-matter candidates and their phenomenology. This work helped advance the DoE's Cosmic Frontier (and also Energy and Intensity Frontiers) by finding synergies between a variety of different experimental efforts, by developing new searches, science targets, and analyses for existing/forthcoming experiments, and by generating ideas for new next-generation experiments.

  11. Amateurism and Professionalism in Work and Learning

    ERIC Educational Resources Information Center

    Edwards, Richard

    2014-01-01

    Purpose: This article aims to explore the concept of amateurism as a form of critique and addition to the concepts of professionalism, professional work and education. Design/methodology/approach: This is a theoretically driven article based upon a review of the historical and sociological literature on amateur-professional relations in various…

  12. Selected Theoretical Comparisons for Bosons

    NASA Astrophysics Data System (ADS)

    Proukakis, Nick P.; Davis, Matthew J.; Gardiner, Simon A.

    2013-02-01

    One of the aims of the organisers of the FINESS conferences, and of the editors of this book, has been to encourage dialogue between researchers working in the general area of non-equilibrium superfluids. The researchers come from widely different backgrounds, and come with a broad array of favourite theoretical techniques. In this chapter we present an incomplete survey of figures from previously published papers that make a comparison between selected subsets of different theoretical methods. The goal is that this compilation of figures, when placed in a broader context, will provide some background for the reader to understand the physical conditions that determine when various theories are useful.

  13. Reconceptualising "Identity Slippage": Additional Language Learning and (L2) Identity Development

    ERIC Educational Resources Information Center

    Armour, William

    2009-01-01

    This paper reconsiders the theoretical concept of "identity slippage" by considering a detailed exegesis of three model conversations taught to learners of Japanese as an additional language. To inform my analysis of these conversations and how they contribute to identity slippage, I have used the work of the systemic-functional linguist Jay Lemke…

  14. Introduction to Theoretical Modelling

    NASA Astrophysics Data System (ADS)

    Davis, Matthew J.; Gardiner, Simon A.; Hanna, Thomas M.; Nygaard, Nicolai; Proukakis, Nick P.; Szymańska, Marzena H.

    2013-02-01

    We briefly overview commonly encountered theoretical notions arising in the modelling of quantum gases, intended to provide a unified background to the `language' and diverse theoretical models presented elsewhere in this book, and aimed particularly at researchers from outside the quantum gases community.

  15. Theoretical and experimental study of thermoacoustic engines

    NASA Astrophysics Data System (ADS)

    Raspet, Richard; Bass, Henry E.; Arnott, W. P.

    1992-12-01

    A three year study of thermoacoustic engines operating as prime movers and refrigerators was completed. The major thrust of this effort was the use and theoretical description of ceramic honeycomb structures as the active element in thermoacoustic engines. An air-filled demonstration prime mover was constructed and demonstrated at Acoustical Society of America and IEE meetings. A helium-filled test prime mover was designed and built an is being employed in studies of the threshold of oscillation as a function of temperature difference and pressure. In addition, acoustically based theories of the thermoacoustic engine have been developed and tested for a parallel plate stack at the Naval Postgraduate School and for a honeycomb stack at the University of Mississippi. Most of this work is described in detail in the attached publications. In this report we will give an overview of the research completed to date and its relationship to work performed at the Naval Postgraduate School and to future work at the University of Mississippi.

  16. Theoretical perspectives on strange physics

    NASA Astrophysics Data System (ADS)

    Ellis, J.

    1983-04-01

    Kaons are heavy enough to have an interesting range of decay modes available to them, and light enough to be produced in sufficient numbers to explore rate modes with satisfying statistics. Kaons and their decays have provided at least two major breakthroughs in fundamental physics: CP violation, and their lack of flavor-changing neutral interactions warned us to expect charm. In addition, K0-anti K0 mixing has provided one of the most elegant and sensitive laboratories for testing quantum mechanics. There is every reason to expect that future generations of kaon experiments with intense sources would add further to fundamental physics. This talk attempts to set future kaon experiments in a general theoretical context, and indicate how they bear upon fundamental theoretical issues. A survey of different experiments which would be done with an Intense Medium Energy Source of Strangeness, including rare K decays, probes of the nature of CP isolation, (SIGMA) decays, hyperon decays and neutrino physics is given.

  17. Theoretical Studies in Elementary Particle Physics

    SciTech Connect

    Collins, John C.; Roiban, Radu S

    2013-04-01

    This final report summarizes work at Penn State University from June 1, 1990 to April 30, 2012. The work was in theoretical elementary particle physics. Many new results in perturbative QCD, in string theory, and in related areas were obtained, with a substantial impact on the experimental program.

  18. Theoretical Chemistry At NASA Ames Research Center

    NASA Technical Reports Server (NTRS)

    Langhoff, Stephen

    1996-01-01

    The theoretical work being carried out in the Computational Chemistry Branch at NASA Ames will be overviewed. This overview will be followed by a more in-depth discussion of our theoretical work to determine molecular opacities for the TiO and water molecules and a discussion of our density function theory (DFT) calculations to determine the harmonic frequencies and intensities to the vibrational bands of polycyclic aromatic hydrocarbons (PAHs) to assess their role as carriers to the unidentified infrared (UIR) bands. Finally, a more in-depth discussion of our work in the area of computational molecular nanotechnology will be presented.

  19. The Basic Theoretical Framework

    NASA Astrophysics Data System (ADS)

    Loeb, Abraham

    Cosmology is by now a mature experimental science. We are privileged to live at a time when the story of genesis (how the Universe started and developed) can be critically explored by direct observations. Looking deep into the Universe through powerful telescopes, we can see images of the Universe when it was younger because of the finite time it takes light to travel to us from distant sources. Existing data sets include an image of the Universe when it was 0.4 million years old (in the form of the cosmic microwave background), as well as images of individual galaxies when the Universe was older than a billion years. But there is a serious challenge: in between these two epochs was a period when the Universe was dark, stars had not yet formed, and the cosmic microwave background no longer traced the distribution of matter. And this is precisely the most interesting period, when the primordial soup evolved into the rich zoo of objects we now see. The observers are moving ahead along several fronts. The first involves the construction of large infrared telescopes on the ground and in space, that will provide us with new photos of the first galaxies. Current plans include ground-based telescopes which are 24-42 m in diameter, and NASA's successor to the Hubble Space Telescope, called the James Webb Space Telescope. In addition, several observational groups around the globe are constructing radio arrays that will be capable of mapping the three-dimensional distribution of cosmic hydrogen in the infant Universe. These arrays are aiming to detect the long-wavelength (redshifted 21-cm) radio emission from hydrogen atoms. The images from these antenna arrays will reveal how the non-uniform distribution of neutral hydrogen evolved with cosmic time and eventually was extinguished by the ultra-violet radiation from the first galaxies. Theoretical research has focused in recent years on predicting the expected signals for the above instruments and motivating these ambitious

  20. Working with Simple Machines

    ERIC Educational Resources Information Center

    Norbury, John W.

    2006-01-01

    A set of examples is provided that illustrate the use of work as applied to simple machines. The ramp, pulley, lever and hydraulic press are common experiences in the life of a student, and their theoretical analysis therefore makes the abstract concept of work more real. The mechanical advantage of each of these systems is also discussed so that…

  1. Theoretical aspects of immunity.

    PubMed

    Deem, Michael W; Hejazi, Pooya

    2010-01-01

    The immune system recognizes a myriad of invading pathogens and their toxic products. It does so with a finite repertoire of antibodies and T cell receptors. We here describe theories that quantify the dynamics of the immune system. We describe how the immune system recognizes antigens by searching the large space of receptor molecules. We consider in some detail the theories that quantify the immune response to influenza and dengue fever. We review theoretical descriptions of the complementary evolution of pathogens that occurs in response to immune system pressure. Methods including bioinformatics, molecular simulation, random energy models, and quantum field theory contribute to a theoretical understanding of aspects of immunity.

  2. Theoretical Characterizaiton of Visual Signatures

    NASA Astrophysics Data System (ADS)

    Kashinski, D. O.; Chase, G. M.; di Nallo, O. E.; Scales, A. N.; Vanderley, D. L.; Byrd, E. F. C.

    2015-05-01

    We are investigating the accuracy of theoretical models used to predict the visible, ultraviolet, and infrared spectra, as well as other properties, of product materials ejected from the muzzle of currently fielded systems. Recent advances in solid propellants has made the management of muzzle signature (flash) a principle issue in weapons development across the calibers. A priori prediction of the electromagnetic spectra of formulations will allow researchers to tailor blends that yield desired signatures and determine spectrographic detection ranges. Quantum chemistry methods at various levels of sophistication have been employed to optimize molecular geometries, compute unscaled vibrational frequencies, and determine the optical spectra of specific gas-phase species. Electronic excitations are being computed using Time Dependent Density Functional Theory (TD-DFT). A full statistical analysis and reliability assessment of computational results is currently underway. A comparison of theoretical results to experimental values found in the literature is used to assess any affects of functional choice and basis set on calculation accuracy. The status of this work will be presented at the conference. Work supported by the ARL, DoD HPCMP, and USMA.

  3. A Theoretical Trombone

    ERIC Educational Resources Information Center

    LoPresto, Michael C.

    2014-01-01

    What follows is a description of a theoretical model designed to calculate the playing frequencies of the musical pitches produced by a trombone. The model is based on quantitative treatments that demonstrate the effects of the flaring bell and cup-shaped mouthpiece sections on these frequencies and can be used to calculate frequencies that…

  4. EET theoretical design techniques

    NASA Technical Reports Server (NTRS)

    Dwoyer, D. L.

    1981-01-01

    As a part of the EET aerodynamics program an out-of-house program was developed and monitored to provide theoretical procedures useful in the design of transport aircraft. The focus of the effort was to provide tools valid in the nonlinear transonic speed range. The effort was divided into two basic areas, inviscid configuration analysis and design procedures and viscous correction procedures.

  5. Additive manufacturing of optical components

    NASA Astrophysics Data System (ADS)

    Heinrich, Andreas; Rank, Manuel; Maillard, Philippe; Suckow, Anne; Bauckhage, Yannick; Rößler, Patrick; Lang, Johannes; Shariff, Fatin; Pekrul, Sven

    2016-08-01

    The development of additive manufacturing methods has enlarged rapidly in recent years. Thereby, the work mainly focuses on the realization of mechanical components, but the additive manufacturing technology offers a high potential in the field of optics as well. Owing to new design possibilities, completely new solutions are possible. This article briefly reviews and compares the most important additive manufacturing methods for polymer optics. Additionally, it points out the characteristics of additive manufactured polymer optics. Thereby, surface quality is of crucial importance. In order to improve it, appropriate post-processing steps are necessary (e.g. robot polishing or coating), which will be discussed. An essential part of this paper deals with various additive manufactured optical components and their use, especially in optical systems for shape metrology (e.g. borehole sensor, tilt sensor, freeform surface sensor, fisheye lens). The examples should demonstrate the potentials and limitations of optical components produced by additive manufacturing.

  6. Studies in theoretical particle physics

    SciTech Connect

    Kaplan, D.B.

    1991-07-01

    This proposal focuses on research on three distinct areas of particle physics: (1) Nonperturbative QCD. I tend to continue work on analytic modelling of nonperturbative effects in the strong interactions. I have been investigating the theoretical connection between the nonrelativistic quark model and QCD. The primary motivation has been to understand the experimental observation of nonzero matrix elements involving current strange quarks in ordinary matter -- which in the quark model has no strange quark component. This has led to my present work on understanding constituent (quark model) quarks as collective excitations of QCD degrees of freedom. (2) Weak Scale Baryogenesis. A continuation of work on baryogenesis in the early universe from weak interactions. In particular, an investigation of baryogenesis occurring during the weak phase transition through anomalous baryon violating processes in the standard model of weak interactions. (3) Flavor and Compositeness. Further investigation of a new mechanism that I recently discovered for dynamical mass generation for fermions, which naturally leads to a family hierarchy structure. A discussion of recent past work is found in the next section, followed by an outline of the proposed research. A recent publication from each of these three areas is attached to this proposal.

  7. Theoretical Approaches to Nanoparticles

    NASA Astrophysics Data System (ADS)

    Kempa, Krzysztof

    Nanoparticles can be viewed as wave resonators. Involved waves are, for example, carrier waves, plasmon waves, polariton waves, etc. A few examples of successful theoretical treatments that follow this approach are given. In one, an effective medium theory of a nanoparticle composite is presented. In another, plasmon polaritonic solutions allow to extend concepts of radio technology, such as an antenna and a coaxial transmission line, to the visible frequency range.

  8. Maternal filicide theoretical framework.

    PubMed

    Mugavin, Marie

    2008-01-01

    The maternal filicide theoretical framework (MFTF) was developed to enrich the understanding of how traumatic experiences during formative years can affect a woman's relationship with her own child. Exposure to a known set of vulnerabilities can foster triggers that predispose a woman to respond impulsively and violently toward her child. Comprehensive assessment of vulnerable families is essential for the prevention of fatal and nonfatal abuse. The MFTF may be applied to both crimes. PMID:18522605

  9. A theoretical trombone

    NASA Astrophysics Data System (ADS)

    LoPresto, Michael C.

    2014-09-01

    What follows is a description of a theoretical model designed to calculate the playing frequencies of the musical pitches produced by a trombone. The model is based on quantitative treatments that demonstrate the effects of the flaring bell and cup-shaped mouthpiece sections on these frequencies and can be used to calculate frequencies that compare well to both the desired frequencies of the musical pitches and those actually played on a real trombone.

  10. Panorama of theoretical physics

    NASA Astrophysics Data System (ADS)

    Mimouni, J.

    2012-06-01

    We shall start this panorama of theoretical physics by giving an overview of physics in general, this branch of knowledge that has been taken since the scientific revolution as the archetype of the scientific discipline. We shall then proceed in showing in what way theoretical physics from Newton to Maxwell, Einstein, Feynman and the like, in all modesty, could be considered as the ticking heart of physics. By its special mode of inquiry and its tantalizing successes, it has capturing the very spirit of the scientific method, and indeed it has been taken as a role model by other disciplines all the way from the "hard" ones to the social sciences. We shall then review how much we know today of the world of matter, both in term of its basic content and in the way it is structured. We will then present the dreams of today's theoretical physics as a way of penetrating into its psyche, discovering in this way its aspirations and longing in much the same way that a child's dreams tell us about his yearning and craving. Yet our understanding of matter has been going in the past decades through a crisis of sort. As a necessary antidote, we shall thus discuss the pitfalls of dreams pushed too far….

  11. Job embeddedness: a multifoci theoretical extension.

    PubMed

    Kiazad, Kohyar; Holtom, Brooks C; Hom, Peter W; Newman, Alexander

    2015-05-01

    Integrating the expanding job embeddedness (JE) literature, in this article we advance a multifoci model of JE that is theoretically grounded in conservation of resources (COR) theory. From COR theory, we posit that employees' motivation to acquire and protect resources explains why they become embedded and how they behave once embedded. Our COR-based JE model highlights contextual antecedents that clarify how employees become embedded within different foci. Its multifoci theoretical lens also illustrates how different forms of work-focused embeddedness differentially affect work outcomes and how they interact with nonwork foci to influence those outcomes. Along with directions for further research, we further discuss theoretical and practical implications of our integrative formulation. PMID:25774569

  12. Theoretical perspectives on strange physics

    SciTech Connect

    Ellis, J.

    1983-04-01

    Kaons are heavy enough to have an interesting range of decay modes available to them, and light enough to be produced in sufficient numbers to explore rare modes with satisfying statistics. Kaons and their decays have provided at least two major breakthroughs in our knowledge of fundamental physics. They have revealed to us CP violation, and their lack of flavor-changing neutral interactions warned us to expect charm. In addition, K/sup 0/-anti K/sup 0/ mixing has provided us with one of our most elegant and sensitive laboratories for testing quantum mechanics. There is every reason to expect that future generations of kaon experiments with intense sources would add further to our knowledge of fundamental physics. This talk attempts to set future kaon experiments in a general theoretical context, and indicate how they may bear upon fundamental theoretical issues. A survey of different experiments which would be done with an Intense Medium Energy Source of Strangeness, including rare K decays, probes of the nature of CP isolation, ..mu.. decays, hyperon decays and neutrino physics is given. (WHK)

  13. Why Problem-Based Learning Works: Theoretical Foundations

    ERIC Educational Resources Information Center

    Marra, Rose M.; Jonassen, David H.; Palmer, Betsy; Luft, Steve

    2014-01-01

    Problem-based learning (PBL) is an instructional method where student learning occurs in the context of solving an authentic problem. PBL was initially developed out of an instructional need to help medical school students learn their basic sciences knowledge in a way that would be more lasting while helping to develop clinical skills…

  14. Divisions of Domestic Work: Revising and Expanding the Theoretical Explanations

    ERIC Educational Resources Information Center

    Kroska, Amy

    2004-01-01

    Using a sample of 101 heterosexual, co-residential couples, the author evaluates four housework theories: gender ideology, relative resources, time availability, and doing gender. Unlike some tests of these theories, the author operationalizes gender ideology as an identity, and the author tests the models on the traditionally feminine chores as…

  15. Recent theoretical work on Cepheids and other types of variables

    NASA Technical Reports Server (NTRS)

    Cox, J. P.

    1980-01-01

    Some important problems in the theory of Cepheids and of other types of variables are pointed out. Three of these are: (1) large-amplitude mode behavior; (2) convection; and (3) Cepheid masses, which must essentially always be inferred indirectly. Of the several types of indirect mass which can be defined, the inferred masses of the 'beat (or double-mode) Cepheids,' seem to be smaller than one expects for this period range by factors of 2-3. For the nonbeat Cepheids, the indirect masses also appear to be low as compared with conventional stellar evolution theory, but by a smaller amount, say some 20-40 percent. Some conceivable ways of explaining these mass discrepancies are discussed. The question of whether the apparently predominantly radial pulsations of the beat Cepheids could be contaminated with a small admixture of nonradial pulsations, so that the use of purely radial pulsation theory may not be applicable to the beat Cepheids is addressed. Some other conjectures which may bear on ordinary or beat Cepheids are offered.

  16. Theoretical models of helicopter rotor noise

    NASA Technical Reports Server (NTRS)

    Hawkings, D. L.

    1978-01-01

    For low speed rotors, it is shown that unsteady load models are only partially successful in predicting experimental levels. A theoretical model is presented which leads to the concept of unsteady thickness noise. This gives better agreement with test results. For high speed rotors, it is argued that present models are incomplete and that other mechanisms are at work. Some possibilities are briefly discussed.

  17. Poverty and Delinquency: A Theoretical Review.

    ERIC Educational Resources Information Center

    Rodman, Hyman

    One of 52 theoretical papers on school crime and its relation to poverty, this chapter reviews the major cultural and structural statements on the relationship between poverty and delinquency. The value stretch perspective, stemming from research on family values and on aspirations is introduced in order to challenge and clarify the basic works of…

  18. ``Impulsar'': Experimental and Theoretical Investigations

    NASA Astrophysics Data System (ADS)

    Apollonov, V. V.

    2008-04-01

    The Objective of the "Impulsar" project is to accomplish a circle of experimental, engineering and technological works on creation of a high efficiency laser rocket engine. The project includes many organizations of the rocket industry and Academy of Sciences of Russia. High repetition rate pulse-periodic CO2 laser system project for launching will be presented. Optical system for 15 MW laser energy delivery and optical matrix of laser engine receiver will by discussed as well. Basic characteristics of the laser-based engine will be compared with theoretical predictions and important stages of further technology implementation (low frequency resonance). Relying on a wide cooperation of different branches of science and industry organizations it is very possible to use the accumulated potential for launching of nano-vehicles during the upcoming 4-5 years.

  19. 'Impulsar': Experimental and Theoretical Investigations

    SciTech Connect

    Apollonov, V. V.

    2008-04-28

    The Objective of the 'Impulsar' project is to accomplish a circle of experimental, engineering and technological works on creation of a high efficiency laser rocket engine. The project includes many organizations of the rocket industry and Academy of Sciences of Russia. High repetition rate pulse-periodic CO{sub 2} laser system project for launching will be presented. Optical system for 15 MW laser energy delivery and optical matrix of laser engine receiver will by discussed as well. Basic characteristics of the laser-based engine will be compared with theoretical predictions and important stages of further technology implementation (low frequency resonance). Relying on a wide cooperation of different branches of science and industry organizations it is very possible to use the accumulated potential for launching of nano-vehicles during the upcoming 4-5 years.

  20. Theoretical Optics: An Introduction

    NASA Astrophysics Data System (ADS)

    Römer, Hartmann

    2005-02-01

    Starting from basic electrodynamics, this volume provides a solid, yet concise introduction to theoretical optics, containing topics such as nonlinear optics, light-matter interaction, and modern topics in quantum optics, including entanglement, cryptography, and quantum computation. The author, with many years of experience in teaching and research, goes way beyond the scope of traditional lectures, enabling readers to keep up with the current state of knowledge. Both content and presentation make it essential reading for graduate and phD students as well as a valuable reference for researchers.

  1. Institute for Theoretical Physics

    SciTech Connect

    Giddings, S.B.; Ooguri, H.; Peet, A.W.; Schwarz, J.H.

    1998-06-01

    String theory is the only serious candidate for a unified description of all known fundamental particles and interactions, including gravity, in a single theoretical framework. Over the past two years, activity in this subject has grown rapidly, thanks to dramatic advances in understanding the dynamics of supersymmetric field theories and string theories. The cornerstone of these new developments is the discovery of duality which relates apparently different string theories and transforms difficult strongly coupled problems of one theory into weakly coupled problems of another theory.

  2. New Theoretical Technique for Alloy Design

    NASA Technical Reports Server (NTRS)

    Ferrante, John

    2005-01-01

    During the last 2 years, there has been a breakthrough in alloy design at the NASA Lewis Research Center. A new semi-empirical theoretical technique for alloys, the BFS Theory (Bozzolo, Ferrante, and Smith), has been used to design alloys on a computer. BFS was used, along with Monte Carlo techniques, to predict the phases of ternary alloys of NiAl with Ti or Cr additions. High concentrations of each additive were used to demonstrate the resulting structures.

  3. Public Works Employment Act of 1977; Hearings before the Subcommittee on Regional and Community Development of the Committee on Environment and Public Works, United States Senate, Ninety-Fifth Congress, First Session on S. 427, a Bill to Provide Additional Authorizations for the Public Works Employment Program, to Authorize a Program for Employment of Teenaged Youth in Community Improvement Projects, and for Other Purposes. February 2, 3, and 4, 1977. Serial No. 95-H5.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Senate Committee on Environment and Public Works.

    This report covers the hearings on Senate bill 427, Public Works Employment Act of 1977, which provides $4 billion in new support for the public works employment program, to establish a program to provide employment, work experience, and skill training to youths in areas of aggravated unemployment, and for other purposes. Included are letters of…

  4. Dark matter: Theoretical perspectives

    SciTech Connect

    Turner, M.S. . Enrico Fermi Inst. Fermi National Accelerator Lab., Batavia, IL )

    1993-01-01

    I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no dark matter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for new physics.'' The compelling candidates are: a very light axion ( 10[sup [minus]6] eV--10[sup [minus]4] eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos.

  5. Dark matter: Theoretical perspectives

    SciTech Connect

    Turner, M.S. |

    1993-01-01

    I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no dark matter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for ``new physics.`` The compelling candidates are: a very light axion ( 10{sup {minus}6} eV--10{sup {minus}4} eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos.

  6. Dark matter: theoretical perspectives.

    PubMed Central

    Turner, M S

    1993-01-01

    I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that (i) there are no dark-matter candidates within the "standard model" of particle physics, (ii) there are several compelling candidates within attractive extensions of the standard model of particle physics, and (iii) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for "new physics." The compelling candidates are a very light axion (10(-6)-10(-4) eV), a light neutrino (20-90 eV), and a heavy neutralino (10 GeV-2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos. PMID:11607395

  7. Theoretical ecology without species

    NASA Astrophysics Data System (ADS)

    Tikhonov, Mikhail

    The sequencing-driven revolution in microbial ecology demonstrated that discrete ``species'' are an inadequate description of the vast majority of life on our planet. Developing a novel theoretical language that, unlike classical ecology, would not require postulating the existence of species, is a challenge of tremendous medical and environmental significance, and an exciting direction for theoretical physics. Here, it is proposed that community dynamics can be described in a naturally hierarchical way in terms of population fluctuation eigenmodes. The approach is applied to a simple model of division of labor in a multi-species community. In one regime, effective species with a core and accessory genome are shown to naturally appear as emergent concepts. However, the same model allows a transition into a regime where the species formalism becomes inadequate, but the eigenmode description remains well-defined. Treating a community as a black box that expresses enzymes in response to resources reveals mathematically exact parallels between a community and a single coherent organism with its own fitness function. This coherence is a generic consequence of division of labor, requires no cooperative interactions, and can be expected to be widespread in microbial ecosystems. Harvard Center of Mathematical Sciences and Applications;John A. Paulson School of Engineering and Applied Sciences.

  8. Out of bounds additive manufacturing

    DOE PAGES

    Holshouser, Chris; Newell, Clint; Palas, Sid; Love, Lonnie J.; Kunc, Vlastimil; Lind, Randall F.; Lloyd, Peter D.; Rowe, John C.; Blue, Craig A.; Duty, Chad E.; et al

    2013-03-01

    Lockheed Martin and Oak Ridge National Laboratory are working on an additive manufacturing system capable of manufacturing components measured not in terms of inches or feet, but multiple yards in all dimensions with the potential to manufacture parts that are completely unbounded in size.

  9. Using SEQUEST with Theoretically Complete Sequence Databases

    NASA Astrophysics Data System (ADS)

    Sadygov, Rovshan G.

    2015-11-01

    SEQUEST has long been used to identify peptides/proteins from their tandem mass spectra and protein sequence databases. The algorithm has proven to be hugely successful for its sensitivity and specificity in identifying peptides/proteins, the sequences of which are present in the protein sequence databases. In this work, we report on work that attempts a new use for the algorithm by applying it to search a complete list of theoretically possible peptides, a de novo-like sequencing. We used freely available mass spectral data and determined a number of unique peptides as identified by SEQUEST. Using masses of these peptides and the mass accuracy of 0.001 Da, we have created a database of all theoretically possible peptide sequences corresponding to the precursor masses. We used our recently developed algorithm for determining all amino acid compositions corresponding to a mass interval, and used a lexicographic ordering to generate theoretical sequences from the compositions. The newly generated theoretical database was many-fold more complex than the original protein sequence database. We used SEQUEST to search and identify the best matches to the spectra from all theoretically possible peptide sequences. We found that SEQUEST cross-correlation score ranked the correct peptide match among the top sequence matches. The results testify to the high specificity of SEQUEST when combined with the high mass accuracy for intact peptides.

  10. Computational and theoretical methods for protein folding.

    PubMed

    Compiani, Mario; Capriotti, Emidio

    2013-12-01

    A computational approach is essential whenever the complexity of the process under study is such that direct theoretical or experimental approaches are not viable. This is the case for protein folding, for which a significant amount of data are being collected. This paper reports on the essential role of in silico methods and the unprecedented interplay of computational and theoretical approaches, which is a defining point of the interdisciplinary investigations of the protein folding process. Besides giving an overview of the available computational methods and tools, we argue that computation plays not merely an ancillary role but has a more constructive function in that computational work may precede theory and experiments. More precisely, computation can provide the primary conceptual clues to inspire subsequent theoretical and experimental work even in a case where no preexisting evidence or theoretical frameworks are available. This is cogently manifested in the application of machine learning methods to come to grips with the folding dynamics. These close relationships suggested complementing the review of computational methods within the appropriate theoretical context to provide a self-contained outlook of the basic concepts that have converged into a unified description of folding and have grown in a synergic relationship with their computational counterpart. Finally, the advantages and limitations of current computational methodologies are discussed to show how the smart analysis of large amounts of data and the development of more effective algorithms can improve our understanding of protein folding.

  11. Comparing geophysical measurements to theoretical estimates for soil mixtures at low pressures

    SciTech Connect

    Wildenschild, D; Berge, P A; Berryman, K G; Bonner, B P; Roberts, J J

    1999-01-15

    The authors obtained good estimates of measured velocities of sand-peat samples at low pressures by using a theoretical method, the self-consistent theory of Berryman (1980), using sand and porous peat to represent the microstructure of the mixture. They were unable to obtain useful estimates with several other theoretical approaches, because the properties of the quartz, air and peat components of the samples vary over several orders of magnitude. Methods that are useful for consolidated rock cannot be applied directly to unconsolidated materials. Instead, careful consideration of microstructure is necessary to adapt the methods successfully. Future work includes comparison of the measured velocity values to additional theoretical estimates, investigation of Vp/Vs ratios and wave amplitudes, as well as modeling of dry and saturated sand-clay mixtures (e.g., Bonner et al., 1997, 1998). The results suggest that field data can be interpreted by comparing laboratory measurements of soil velocities to theoretical estimates of velocities in order to establish a systematic method for predicting velocities for a full range of sand-organic material mixtures at various pressures. Once the theoretical relationship is obtained, it can be used to estimate the soil composition at various depths from field measurements of seismic velocities. Additional refining of the method for relating velocities to soil characteristics is useful for development inversion algorithms.

  12. Theoretical particle physics

    SciTech Connect

    Gottlieb, S.A.; Hendry, A.W.; Kostelecky, V.A.; Lichtenberg, D.B.

    1992-04-01

    We have carried out research in lattice gauge theory, superstring theory, supersymmetry, the solar neutrino puzzle, QCD perturbation theory, and phenomenological models of hadrons. In this report, we summarize our work in each of these areas.

  13. Work-school conflict and health outcomes: beneficial resources for working college students.

    PubMed

    Park, Youngah; Sprung, Justin M

    2013-10-01

    This study extends prior college student employment research by examining health as an outcome variable. Using 2-wave data from a sample of 216 student workers, this study examined work-school conflict as a predictor of psychological and physical health among working college students. Additionally, 3 resource-providing variables--work-school facilitation, supervisor work-school support, and personal fulfillment at work--were tested for buffering effects in the relation between work-school conflict and health. Results demonstrated that work-school conflict was a significant predictor of psychological health but not physical health. All 3 resource-providing variables ameliorated the negative relation between work-school conflict and psychological health, whereas only personal fulfillment weakened the positive relation between work-school conflict and physical symptoms. These findings suggest the benefits of work-school facilitation, supervisor work-school support, and personal fulfillment in minimizing the detrimental effects of work-school conflict on health outcomes. Theoretical and practical implications for researchers, educational institutions, and organizations are discussed.

  14. Education and Work

    ERIC Educational Resources Information Center

    Trostel, Philip; Walker, Ian

    2006-01-01

    This paper examines the relationship between the incentives to work and to invest in human capital through education in a lifecycle optimizing model. These incentives are shown to be mutually reinforcing in a simple stylized model. This theoretical prediction is investigated empirically using three large micro datasets covering a broad range of…

  15. Theoretical prediction of crystal structures of rubrene

    NASA Astrophysics Data System (ADS)

    Obata, Shigeaki; Miura, Toshiaki; Shimoi, Yukihiro

    2014-01-01

    We theoretically predict crystal structures and molecular arrangements for rubrene molecule using CONFLEX program and compare them with the experimental ones. The most, second-most, and fourth-most stable predicted crystal structures show good agreement with the triclinic, orthorhombic, and monoclinic polymorphs of rubrene, respectively. The change in molecular conformation is also predicted between crystalline and gas phases: the tetracene backbone takes flat conformation in crystalline phase as in the observed structure. Meanwhile, it is twisted in gas phase. The theoretical prediction method used in this work provides the successful results on the determination of the three kinds of crystal structures and molecular arrangements for rubrene molecule.

  16. Theoretical Studies of Hydrogen Storage Alloys.

    SciTech Connect

    Jonsson, Hannes

    2012-03-22

    Theoretical calculations were carried out to search for lightweight alloys that can be used to reversibly store hydrogen in mobile applications, such as automobiles. Our primary focus was on magnesium based alloys. While MgH{sub 2} is in many respects a promising hydrogen storage material, there are two serious problems which need to be solved in order to make it useful: (i) the binding energy of the hydrogen atoms in the hydride is too large, causing the release temperature to be too high, and (ii) the diffusion of hydrogen through the hydride is so slow that loading of hydrogen into the metal takes much too long. In the first year of the project, we found that the addition of ca. 15% of aluminum decreases the binding energy to the hydrogen to the target value of 0.25 eV which corresponds to release of 1 bar hydrogen gas at 100 degrees C. Also, the addition of ca. 15% of transition metal atoms, such as Ti or V, reduces the formation energy of interstitial H-atoms making the diffusion of H-atoms through the hydride more than ten orders of magnitude faster at room temperature. In the second year of the project, several calculations of alloys of magnesium with various other transition metals were carried out and systematic trends in stability, hydrogen binding energy and diffusivity established. Some calculations of ternary alloys and their hydrides were also carried out, for example of Mg{sub 6}AlTiH{sub 16}. It was found that the binding energy reduction due to the addition of aluminum and increased diffusivity due to the addition of a transition metal are both effective at the same time. This material would in principle work well for hydrogen storage but it is, unfortunately, unstable with respect to phase separation. A search was made for a ternary alloy of this type where both the alloy and the corresponding hydride are stable. Promising results were obtained by including Zn in the alloy.

  17. [Food additives and healthiness].

    PubMed

    Heinonen, Marina

    2014-01-01

    Additives are used for improving food structure or preventing its spoilage, for example. Many substances used as additives are also naturally present in food. The safety of additives is evaluated according to commonly agreed principles. If high concentrations of an additive cause adverse health effects for humans, a limit of acceptable daily intake (ADI) is set for it. An additive is a risk only when ADI is exceeded. The healthiness of food is measured on the basis of nutrient density and scientifically proven effects.

  18. Leading Work with Young People

    ERIC Educational Resources Information Center

    Harrison, Roger, Ed.; Benjamin, Cathy, Ed.; Curran, Sheila, Ed.; Hunter, Rob, Ed.

    2007-01-01

    "Leading Work with Young People" provides a selection of writing from a complex and dynamic field of work. The editors bring together key readings and newly commissioned material to present a variety of theoretical and practical perspectives on leading and managing work with young people. The book will equip students with the knowledge, skills,…

  19. Work-family conflicts and work performance.

    PubMed

    Roth, Lawrence; David, Emily M

    2009-08-01

    Prior research indicates that work-family conflict interferes with family far more than it interferes with work. Conservation of resources provides a possible explanation: when shifting resources from family is no longer sufficient to maintain satisfactory work performance, then workers must acquire additional resources or reduce investments in work. One source of such additional resources could be high performance peers in the work group. The performance of workers with resource-rich peers may be less adversely affected by work-family conflict. In this study, 136 employees of a wholesale distribution firm (61% women, 62% minority) working in groups of 7 to 11 in manual labor and low-level administrative jobs rated their own work-to-family conflict. Their supervisors rated workers' performance. Hierarchical regression analysis indicated that work-to-family conflict increasingly adversely affected job performance as work group performance decreased. Hence, work group performance may be an important moderator of the effects of work-family conflict.

  20. PREFACE International Conference on Theoretical Physics Dubna-Nano 2010

    NASA Astrophysics Data System (ADS)

    Osipov, Vladimir; Nesterenko, Valentin; Shukrinov, Yury

    2010-11-01

    The International Conference on Theoretical Physics 'Dubna-Nano2010' was held on 5-10 July 2010, at the Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow region, Russia. The previous conference of this series was at Dubna in 2008. The conference provided the opportunity for the presentation and discussion of theoretical and experimental advances in the rapidly growing area of nanophysics, with the accent on its theoretical aspects. The multidisciplinary character of the conference allowed an effective exchange of ideas between different areas of nanophysics. The following topics were covered: carbon nanosystems (graphene, nanotubes, fullerenes), quantum dots, quantum transport, spectroscopy and dynamics of atomic clusters, Josephson junctions, modelling, applications and perspectives. Approximately 120 scientists from 26 countries participated in the conference. The program included 63 oral talks and 70 posters. The 62 contributions are included in these proceedings. We would like to express our gratitude to all participants for their presentations and discussions, which made the conference indeed successful. We are deeply indebted to the members of the International Advisory Committee (Professors T Ando, J Fabian, F Guinea, P Hawrylak, K Kadowaki, T Koyama, Yu I Latushev, Yu E Lozovik, M Machida, B K Nikolic, N F Pedersen, P-G Reinhard, J M Rost, A Ya Vul') and the Local Organizing Committee for their fruitful work. The financial support of BLTP JINR, Russian Foundation for Basic Research, Heisenberg-Landau Program and Bogoliubov-Infeld Program was of a great importance. Additional information about 'Dubna-Nano2010' is available at the homepage http://theor.jinr.ru/~nano10. Vladimir Osipov, Valentin Nesterenko and Yury Shukrinov Editors

  1. Fluoride Anion Recognition by a Multifunctional Urea Derivative: An Experimental and Theoretical Study.

    PubMed

    Schiller, Jana; Pérez-Ruiz, Raúl; Sampedro, Diego; Marqués-López, Eugenia; Herrera, Raquel P; Díaz Díaz, David

    2016-05-09

    In this work we demonstrate the ability of a multifaceted N,N'-disubstituted urea to selectively recognize fluoride anion (F(-)) among other halides. This additional function is now added to its already reported organocatalytic and organogelator properties. The signaling mechanism relies on the formation of a charge-transfer (CT) complex between the urea-based sensor and F¯ in the ground state with a high association constant as demonstrated by absorption and fluorescence spectroscopy. The nature of the hydrogen bonding interaction between the sensor and F¯ was established by ¹H-NMR studies and theoretical calculations. Moreover, the recovery of the sensor was achieved by addition of methanol.

  2. Fluoride Anion Recognition by a Multifunctional Urea Derivative: An Experimental and Theoretical Study.

    PubMed

    Schiller, Jana; Pérez-Ruiz, Raúl; Sampedro, Diego; Marqués-López, Eugenia; Herrera, Raquel P; Díaz Díaz, David

    2016-01-01

    In this work we demonstrate the ability of a multifaceted N,N'-disubstituted urea to selectively recognize fluoride anion (F(-)) among other halides. This additional function is now added to its already reported organocatalytic and organogelator properties. The signaling mechanism relies on the formation of a charge-transfer (CT) complex between the urea-based sensor and F¯ in the ground state with a high association constant as demonstrated by absorption and fluorescence spectroscopy. The nature of the hydrogen bonding interaction between the sensor and F¯ was established by ¹H-NMR studies and theoretical calculations. Moreover, the recovery of the sensor was achieved by addition of methanol. PMID:27171087

  3. Fluoride Anion Recognition by a Multifunctional Urea Derivative: An Experimental and Theoretical Study

    PubMed Central

    Schiller, Jana; Pérez-Ruiz, Raúl; Sampedro, Diego; Marqués-López, Eugenia; Herrera, Raquel P.; Díaz Díaz, David

    2016-01-01

    In this work we demonstrate the ability of a multifaceted N,N′-disubstituted urea to selectively recognize fluoride anion (F−) among other halides. This additional function is now added to its already reported organocatalytic and organogelator properties. The signaling mechanism relies on the formation of a charge-transfer (CT) complex between the urea-based sensor and F¯ in the ground state with a high association constant as demonstrated by absorption and fluorescence spectroscopy. The nature of the hydrogen bonding interaction between the sensor and F¯ was established by 1H-NMR studies and theoretical calculations. Moreover, the recovery of the sensor was achieved by addition of methanol. PMID:27171087

  4. Theoretical kinetics of O + C2H4

    DOE PAGES

    Li, Xiaohu; Jasper, Ahren W.; Zádor, Judit; Miller, James A.; Klippenstein, Stephen J.

    2016-06-01

    The reaction of atomic oxygen with ethylene is a fundamental oxidation step in combustion and is prototypical of reactions in which oxygen adds to double bonds. For 3O+C2H4 and for this class of reactions generally, decomposition of the initial adduct via spin-allowed reaction channels on the triplet surface competes with intersystem crossing (ISC) and a set of spin-forbidden reaction channels on the ground-state singlet surface. The two surfaces share some bimolecular products but feature different intermediates, pathways, and transition states. In addition, the overall product branching is therefore a sensitive function of the ISC rate. The 3O+C2H4 reaction has beenmore » extensively studied, but previous experimental work has not provided detailed branching information at elevated temperatures, while previous theoretical studies have employed empirical treatments of ISC. Here we predict the kinetics of 3O+C2H4 using an ab initio transition state theory based master equation (AITSTME) approach that includes an a priori description of ISC. Specifically, the ISC rate is calculated using Landau–Zener statistical theory, consideration of the four lowest-energy electronic states, and a direct classical trajectory study of the product branching immediately after ISC. The present theoretical results are largely in good agreement with existing low-temperature experimental kinetics and molecular beam studies. Good agreement is also found with past theoretical work, with the notable exception of the predicted product branching at elevated temperatures. Above ~1000 K, we predict CH2CHO+H and CH2+CH2O as the major products, which differs from the room temperature preference for CH3+HCO (which is assumed to remain at higher temperatures in some models) and from the prediction of a previous detailed master equation study.« less

  5. Recovery after Work: The Role of Work Beliefs in the Unwinding Process

    PubMed Central

    Zoupanou, Zoe; Cropley, Mark; Rydstedt, Leif W.

    2013-01-01

    According to the Effort-Recovery model, mental or physical detachment from work is an important mechanism of work related recovery, as delayed recovery has been associated with range of negative health symptoms. In this paper, we examine whether recovery from work (in the form of mentally disengagement from work) is affected by the concept of ‘work ethic’, which refers to beliefs workers hold about their work and leisure and the effects of experiencing interruptions at work. Two indices of post-work recovery were utilized: problem solving pondering and psychological detachment. The study was conducted with 310 participants employed from diverse occupational sectors. Main effects of positive and negative appraisal of work interruption and beliefs were analysed using mediated and moderated regression analysis on problem-solving pondering and detachment. Weakened belief in wasted time as a partial mediator, reduced problem-solving pondering post work when interruptions were appraised as positive, and a high evaluation of leisure partially mediated problem-solving pondering when interruptions were appraised as positive. The results also showed that a high evaluation of centrality of work and leisure moderated the effect of negative appraisal of work interruption on elevated problem-solving pondering. Positive appraisal of work interruption was related to problem-solving pondering, and the strength of this association was further moderated by a strong belief in delay of gratification. In addition, employees' positive appraisal of work interruption was related to work detachment, and the strength of this association was further moderated by strong beliefs in hard work and self-reliance. These findings are discussed in terms of their theoretical and practical implications for employees who are strongly influenced by such work beliefs. PMID:24349060

  6. Working Group 7 Summary

    SciTech Connect

    Nagaitsev S.; Berg J.

    2012-06-10

    The primary subject of working group 7 at the 2012 Advanced Accelerator Concepts Workshop was muon accelerators for a muon collider or neutrino factory. Additionally, this working group included topics that did not fit well into other working groups. Two subjects were discussed by more than one speaker: lattices to create a perfectly integrable nonlinear lattice, and a Penning trap to create antihydrogen.

  7. The NASTRAN theoretical manual

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Designed to accommodate additions and modifications, this commentary on NASTRAN describes the problem solving capabilities of the program in a narrative fashion and presents developments of the analytical and numerical procedures that underlie the program. Seventeen major sections and numerous subsections cover; the organizational aspects of the program, utility matrix routines, static structural analysis, heat transfer, dynamic structural analysis, computer graphics, special structural modeling techniques, error analysis, interaction between structures and fluids, and aeroelastic analysis.

  8. Masculinities in Higher Education: Theoretical and Practical Considerations

    ERIC Educational Resources Information Center

    Laker, Jason A., Ed.; Davis, Tracy, Ed.

    2011-01-01

    "Masculinities in Higher Education" provides empirical evidence, theoretical support, and developmental interventions for educators working with college men both in and out of the classroom. The critical philosophical perspective of the text challenges the status-quo and offers theoretically sound educational strategies to successfully promote…

  9. Proof-Theoretic Semantics for a Natural Language Fragment

    NASA Astrophysics Data System (ADS)

    Francez, Nissim; Dyckhoff, Roy

    We propose a Proof - Theoretic Semantics (PTS) for a (positive) fragment E+0 of Natural Language (NL) (English in this case). The semantics is intended [7] to be incorporated into actual grammars, within the framework of Type - Logical Grammar (TLG) [12]. Thereby, this semantics constitutes an alternative to the traditional model - theoretic semantics (MTS), originating in Montague's seminal work [11], used in TLG.

  10. TAD- THEORETICAL AERODYNAMICS PROGRAM

    NASA Technical Reports Server (NTRS)

    Barrowman, J.

    1994-01-01

    This theoretical aerodynamics program, TAD, was developed to predict the aerodynamic characteristics of vehicles with sounding rocket configurations. These slender, axisymmetric finned vehicle configurations have a wide range of aeronautical applications from rockets to high speed armament. Over a given range of Mach numbers, TAD will compute the normal force coefficient derivative, the center-of-pressure, the roll forcing moment coefficient derivative, the roll damping moment coefficient derivative, and the pitch damping moment coefficient derivative of a sounding rocket configured vehicle. The vehicle may consist of a sharp pointed nose of cone or tangent ogive shape, up to nine other body divisions of conical shoulder, conical boattail, or circular cylinder shape, and fins of trapezoid planform shape with constant cross section and either three or four fins per fin set. The characteristics computed by TAD have been shown to be accurate to within ten percent of experimental data in the supersonic region. The TAD program calculates the characteristics of separate portions of the vehicle, calculates the interference between separate portions of the vehicle, and then combines the results to form a total vehicle solution. Also, TAD can be used to calculate the characteristics of the body or fins separately as an aid in the design process. Input to the TAD program consists of simple descriptions of the body and fin geometries and the Mach range of interest. Output includes the aerodynamic characteristics of the total vehicle, or user-selected portions, at specified points over the mach range. The TAD program is written in FORTRAN IV for batch execution and has been implemented on an IBM 360 computer with a central memory requirement of approximately 123K of 8 bit bytes. The TAD program was originally developed in 1967 and last updated in 1972.

  11. Theoretical studies of photosynthesis

    SciTech Connect

    Thompson, M.A.

    1990-01-01

    The conversion of light energy to chemical energy by the process of photosynthetic charge separation is one of the most important chemical transformation for life on this planet. With the atomic level structures of photosynthetic reaction centers (RC) for some bacteria now known, one can attempt to attain a more complete understanding of the properties and mechanisms of these systems. In this dissertation theoretical studies on both monomeric bacteriochlorophylls (BChl) and aggregates of these related pigments representing models of the RC are presented. Models for the effects of nearby charged and polar groups on monomeric BChls and how these relate to spectroscopic shifts in the absorption spectrum of the RC are discussed. The calculated properties of the BChl dimer or special pair is best described in terms of a dimer of strongly interacting BChl monomers rather than the more traditional coupled chromophore model. That this BChl dimer is responsible for the lowest absorption band in the UV/vis spectrum of RCs is well described by these results. A description of these interactions in the BChl dimer is presented using a simpler model system composed of Mg-bacteriochlorin dimers. A model of the RC consisting of the four BChlbs and two bacteriopheophytins as well as some of the surrounding amino acids of the RC protein is sufficient to give a reasonable description of the calculated UV/vis spectrum of the RC. These results show that the lowest two excited states of the RC are attributed to the BChl dimer. This strengthens the identification of the second lowest excited state with the shoulder seen at 850 nm in experimental spectra as the upper exciton-like component of the BChl dimer. Charge transfer (CT) states are calculated and demonstrate the preference for flow of charge in the RC along only one of its branches.

  12. QTIPs: Questionable theoretical and interpretive practices in social psychology.

    PubMed

    Brandt, Mark J; Proulx, Travis

    2015-01-01

    One possible consequence of ideological homogeneity is the misinterpretation of data collected with otherwise solid methods. To help identify these issues outside of politically relevant research, we name and give broad descriptions to three questionable interpretive practices described by Duarte et al. and introduce three additional questionable theoretical practices that also reduce the theoretical power and paradigmatic scope of psychology.

  13. STM fingerprints of point defects in graphene: a theoretical prediction

    SciTech Connect

    Amara, Hakim; Latil, Sylvain; Meunier, Vincent; Lambin, Philippe; Charlier, Jean Christophe

    2007-01-01

    Scanning tunneling microscopy (STM) is one of the most appropriate techniques to investigate the atomic structure of carbon nanomaterials. However, the experimental identification of topological and nontopological modifications of the hexagonal network of sp{sup 2} carbon nanostructures remains a great challenge. The goal of the present theoretical work is to predict the typical electronic features of a few defects that are likely to occur in sp{sup 2} carbon nanostructures, such as atomic vacancy, divacancy, adatom, and Stone-Wales defect. The modifications induced by those defects in the electronic properties of the graphene sheet are investigated using first-principles calculations. In addition, computed constant-current STM images of these defects are calculated within a tight-binding approach in order to facilitate the interpretation of STM images of defected carbon nanostructures.

  14. Information theoretic approaches to multidimensional neural computations

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Jeffrey D.

    Many systems in nature process information by transforming inputs from their environments into observable output states. These systems are often difficult to study because they are performing computations on multidimensional inputs with many degrees of freedom using highly nonlinear functions. The work presented in this dissertation deals with some of the issues involved with characterizing real-world input/output systems and understanding the properties of idealized systems using information theoretic methods. Using the principle of maximum entropy, a family of models are created that are consistent with certain measurable correlations from an input/output dataset but are maximally unbiased in all other respects, thereby eliminating all unjustified assumptions about the computation. In certain cases, including spiking neurons, we show that these models also minimize the mutual information. This property gives one the advantage of being able to identify the relevant input/output statistics by calculating their information content. We argue that these maximum entropy models provide a much needed quantitative framework for characterizing and understanding sensory processing neurons that are selective for multiple stimulus features. To demonstrate their usefulness, these ideas are applied to neural recordings from macaque retina and thalamus. These neurons, which primarily respond to two stimulus features, are shown to be well described using only first and second order statistics, indicating that their firing rates encode information about stimulus correlations. In addition to modeling multi-feature computations in the relevant feature space, we also show that maximum entropy models are capable of discovering the relevant feature space themselves. This technique overcomes the disadvantages of two commonly used dimensionality reduction methods and is explored using several simulated neurons, as well as retinal and thalamic recordings. Finally, we ask how neurons in a

  15. The theoretical limits of source and channel coding

    NASA Technical Reports Server (NTRS)

    Dolinar, S. J.; Pollara, F.

    1990-01-01

    The theoretical relationship among signal power, distortion, and bandwidth for several source and channel models is presented. The work is intended as a reference for the evaluation of the performance of specific data compression algorithms.

  16. Cincinnati Big Area Additive Manufacturing (BAAM)

    SciTech Connect

    Duty, Chad E.; Love, Lonnie J.

    2015-03-04

    Oak Ridge National Laboratory (ORNL) worked with Cincinnati Incorporated (CI) to demonstrate Big Area Additive Manufacturing which increases the speed of the additive manufacturing (AM) process by over 1000X, increases the size of parts by over 10X and shows a cost reduction of over 100X. ORNL worked with CI to transition the Big Area Additive Manufacturing (BAAM) technology from a proof-of-principle (TRL 2-3) demonstration to a prototype product stage (TRL 7-8).

  17. Research in Theoretical Particle Physics

    SciTech Connect

    Feldman, Hume A; Marfatia, Danny

    2014-09-24

    This document is the final report on activity supported under DOE Grant Number DE-FG02-13ER42024. The report covers the period July 15, 2013 – March 31, 2014. Faculty supported by the grant during the period were Danny Marfatia (1.0 FTE) and Hume Feldman (1% FTE). The grant partly supported University of Hawaii students, David Yaylali and Keita Fukushima, who are supervised by Jason Kumar. Both students are expected to graduate with Ph.D. degrees in 2014. Yaylali will be joining the University of Arizona theory group in Fall 2014 with a 3-year postdoctoral appointment under Keith Dienes. The group’s research covered topics subsumed under the Energy Frontier, the Intensity Frontier, and the Cosmic Frontier. Many theoretical results related to the Standard Model and models of new physics were published during the reporting period. The report contains brief project descriptions in Section 1. Sections 2 and 3 lists published and submitted work, respectively. Sections 4 and 5 summarize group activity including conferences, workshops and professional presentations.

  18. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Fletcher, James C. (Inventor); Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1992-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  19. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1993-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of the additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  20. Additional Types of Neuropathy

    MedlinePlus

    ... A A Listen En Español Additional Types of Neuropathy Charcot's Joint Charcot's Joint, also called neuropathic arthropathy, ... can stop bone destruction and aid healing. Cranial Neuropathy Cranial neuropathy affects the 12 pairs of nerves ...

  1. Food Additives and Hyperkinesis

    ERIC Educational Resources Information Center

    Wender, Ester H.

    1977-01-01

    The hypothesis that food additives are causally associated with hyperkinesis and learning disabilities in children is reviewed, and available data are summarized. Available from: American Medical Association 535 North Dearborn Street Chicago, Illinois 60610. (JG)

  2. Smog control fuel additives

    SciTech Connect

    Lundby, W.

    1993-06-29

    A method is described of controlling, reducing or eliminating, ozone and related smog resulting from photochemical reactions between ozone and automotive or industrial gases comprising the addition of iodine or compounds of iodine to hydrocarbon-base fuels prior to or during combustion in an amount of about 1 part iodine per 240 to 10,000,000 parts fuel, by weight, to be accomplished by: (a) the addition of these inhibitors during or after the refining or manufacturing process of liquid fuels; (b) the production of these inhibitors for addition into fuel tanks, such as automotive or industrial tanks; or (c) the addition of these inhibitors into combustion chambers of equipment utilizing solid fuels for the purpose of reducing ozone.

  3. Order Theoretical Semantic Recommendation

    SciTech Connect

    Joslyn, Cliff A.; Hogan, Emilie A.; Paulson, Patrick R.; Peterson, Elena S.; Stephan, Eric G.; Thomas, Dennis G.

    2013-07-23

    Mathematical concepts of order and ordering relations play multiple roles in semantic technologies. Discrete totally ordered data characterize both input streams and top-k rank-ordered recommendations and query output, while temporal attributes establish numerical total orders, either over time points or in the more complex case of startend temporal intervals. But also of note are the fully partially ordered data, including both lattices and non-lattices, which actually dominate the semantic strcuture of ontological systems. Scalar semantic similarities over partially-ordered semantic data are traditionally used to return rank-ordered recommendations, but these require complementation with true metrics available over partially ordered sets. In this paper we report on our work in the foundations of partial order measurement in ontologies, with application to top-k semantic recommendation in workflows.

  4. Theoretical and experimental study on electron interactions with chlorobenzene: Shape resonances and differential cross sections

    NASA Astrophysics Data System (ADS)

    Barbosa, Alessandra Souza; Varella, Márcio T. do N.; Sanchez, Sergio d'A.; Ameixa, João; Blanco, Francisco; García, Gustavo; Limão-Vieira, Paulo; Ferreira da Silva, Filipe; Bettega, Márcio H. F.

    2016-08-01

    In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in the high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7∘ to 110∘. From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene.

  5. Theoretical and experimental study on electron interactions with chlorobenzene: Shape resonances and differential cross sections.

    PubMed

    Barbosa, Alessandra Souza; Varella, Márcio T do N; Sanchez, Sergio d'A; Ameixa, João; Blanco, Francisco; García, Gustavo; Limão-Vieira, Paulo; Ferreira da Silva, Filipe; Bettega, Márcio H F

    2016-08-28

    In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in the high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7(∘) to 110(∘). From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene. PMID:27586926

  6. Addition of one and two units of C{sub 2}H to styrene: A theoretical study of the C{sub 10}H{sub 9} and C{sub 12}H{sub 9} systems and implications toward growth of polycyclic aromatic hydrocarbons at low temperatures

    SciTech Connect

    Landera, Alexander; Mebel, Alexander M.; Kaiser, Ralf I.

    2011-01-14

    Various mechanisms of the formation of naphthalene and its substituted derivatives have been investigated by ab initio G3(MP2,CC)/B3LYP/6-311G** calculations of potential energy surfaces for the reactions of one and two C{sub 2}H additions to styrene combined with RRKM calculations of product branching ratios under single-collision conditions. The results show that for the C{sub 2}H + styrene reaction, the dominant routes are H atom eliminations from the initial adducts; C{sub 2}H addition to the vinyl side chain of styrene is predicted to produce trans or cis conformations of phenylvinylacetylene (t- and c-PVA), whereas C{sub 2}H addition to the ortho carbon in the ring is expected to lead to the formation of o-ethynylstyrene. Although various reaction channels may lead to a second ring closure and the formation of naphthalene, they are not competitive with the direct H loss channels producing PVAs and ethynylstyrenes. However, c-PVA and o-ethynylstyrene may undergo a second addition of the ethynyl radical to ultimately produce substituted naphthalene derivatives. {alpha}- and {beta}-additions of C{sub 2}H to the side chain in c-PVA are calculated to form 2-ethynyl-naphthalene with branching ratios of about 30% and 96%, respectively; the major product in the case of {alpha}-addition would be cis-1-hexene-3,5-diynyl-benzene produced by an immediate H elimination from the initial adduct. C{sub 2}H addition to the ethynyl side chain in o-ethynylstyrene is predicted to lead to the formation of 1-ethynyl-naphthalene as the dominant product. The C{sub 2}H + styrene {yields}t-PVA+ H/c-PVA+ H/o-ethynylstyrene, C{sub 2}H +c-PVA{yields} 2-ethynyl-naphthalene + H, and C{sub 2}H +o-ethynylstyrene {yields} 1-ethynyl-naphthalene + H reactions are calculated to occur without a barrier and with high exothermicity, with all intermediates, transition states, and products lying significantly lower in energy than the initial reactants, and hence to be fast even at very low

  7. Rehabilitation Counselor Work Environment: Examining Congruence with Prototypic Work Personality

    ERIC Educational Resources Information Center

    Zanskas, Stephen; Strohmer, Douglas C.

    2010-01-01

    The profession of rehabilitation counseling has undergone extensive empirical study. Absent from this research has been a theoretical basis for describing and understanding the profession and its associated work environment. The focus of this study was to further our understanding of the nature of the rehabilitation counselor's work environment…

  8. Additive Manufacturing Infrared Inspection

    NASA Technical Reports Server (NTRS)

    Gaddy, Darrell

    2014-01-01

    Additive manufacturing is a rapid prototyping technology that allows parts to be built in a series of thin layers from plastic, ceramics, and metallics. Metallic additive manufacturing is an emerging form of rapid prototyping that allows complex structures to be built using various metallic powders. Significant time and cost savings have also been observed using the metallic additive manufacturing compared with traditional techniques. Development of the metallic additive manufacturing technology has advanced significantly over the last decade, although many of the techniques to inspect parts made from these processes have not advanced significantly or have limitations. Several external geometry inspection techniques exist such as Coordinate Measurement Machines (CMM), Laser Scanners, Structured Light Scanning Systems, or even traditional calipers and gages. All of the aforementioned techniques are limited to external geometry and contours or must use a contact probe to inspect limited internal dimensions. This presentation will document the development of a process for real-time dimensional inspection technique and digital quality record of the additive manufacturing process using Infrared camera imaging and processing techniques.

  9. Intimate partner aggression and women's work outcomes.

    PubMed

    LeBlanc, Manon Mireille; Barling, Julian; Turner, Nick

    2014-10-01

    Using conservation of resources theory, we examined the relationship between intimate partner aggression enacted against heterosexual women and 3 types of work-related outcomes for these women: withdrawal while at work (i.e., cognitive distraction, work neglect), withdrawal from work (i.e., partial absenteeism, intentions to quit), and performance. In Study 1, we compared withdrawal both at and from work across 3 clinically categorized groups of women (n = 50), showing that experiencing physical aggression is related to higher work neglect. We replicated and extended these findings in Study 2 using a community sample of employed women (n = 249) by considering the incremental variance explained by both physical aggression and psychological aggression on these same outcomes. Results showed that physical aggression predicted higher levels of withdrawal both at and from work, with psychological aggression predicting additional variance in partial absenteeism over and above the effects of physical aggression. Study 3 extended the model to include academic performance as an outcome in a sample of female college students (n = 122) in dating relationships. Controlling for the women's conscientiousness, psychological aggression predicted lower academic performance after accounting for the effects of physical aggression. We discuss theoretical and practical implications of these results, as well as directions for future research. PMID:25068818

  10. Phenylethynyl Containing Reactive Additives

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2002-01-01

    Phenylethynyl containing reactive additives were prepared from aromatic diamine, containing phenylethvnvl groups and various ratios of phthalic anhydride and 4-phenylethynviphthalic anhydride in glacial acetic acid to form the imide in one step or in N-methyl-2-pvrrolidinone to form the amide acid intermediate. The reactive additives were mixed in various amounts (10% to 90%) with oligomers containing either terminal or pendent phenylethynyl groups (or both) to reduce the melt viscosity and thereby enhance processability. Upon thermal cure, the additives react and become chemically incorporated into the matrix and effect an increase in crosslink density relative to that of the host resin. This resultant increase in crosslink density has advantageous consequences on the cured resin properties such as higher glass transition temperature and higher modulus as compared to that of the host resin.

  11. Theoretical horizontal-branch evolution

    NASA Technical Reports Server (NTRS)

    Sweigart, Allen V.

    1987-01-01

    The general features of the theoretical evolution of canonical horizontal-branch (HB) stars are briefly reviewed with specific emphasis on the track morphology in the HR diagram and the determination of the globular cluster helium abundance. The observational evidence for the occurrence of semiconvection is discussed together with some remaining theoretical uncertainty.

  12. Theoretical Study of a Spherical Plasma Focus

    NASA Astrophysics Data System (ADS)

    Ay, Yasar

    A theoretical model is developed for two concentric electrodes spherical plasma focus device in order to investigate the plasma sheath dynamics, radiative emission, and the ion properties. The work focuses on the model development of the plasma sheath dynamics and its validation, followed by studying of the radiation effects and the beam-ion properties in such unique geometry as a pulsed source for neutrons, soft and hard x-rays, and electron and ion beams. Chapter 1 is an introduction on fusion systems including plasma focus. Chapter 2 is an extensive literature survey on plasma focus modeling and experiments including the various radiations and their mechanism. Chapter 3 details modeling and validation of the plasma sheath dynamics model with comparison between hydrogen, deuterium, tritium and deuterium-tritium mixture for the production of pulsed neutrons. Chapter 4 is a study of the radiative phase, in which neutron yield is investigated, as well as the predicted beam-ion properties. Chapter 5 summarizes and discusses the results. Chapter 6 provides concluding remarks and proposed future works. The phases of the developed model are the rundown phase I, rundown phase II, the reflected phase and a radiative phase. The rundown phase I starts immediately after the completion of the gas breakdown and ends when the current sheath reaches the equator point of the spherical shape. Then immediately followed by rundown phase II to start and it ends when the shock front hits the axis, which is the beginning of the reflected shock phase. Reflected shock front moves towards the incoming current sheath and meets it which is both the end of the reflected shock phase and the beginning of the radiative phase. After the reflected shock front and the current sheath meet, the current sheath continues to move radially inward by compressing the produced plasma column until it reaches the axis. Since the discharge current contains important information about the plasma dynamic

  13. Multifunctional fuel additives

    SciTech Connect

    Baillargeon, D.J.; Cardis, A.B.; Heck, D.B.

    1991-03-26

    This paper discusses a composition comprising a major amount of a liquid hydrocarbyl fuel and a minor low-temperature flow properties improving amount of an additive product of the reaction of a suitable diol and product of a benzophenone tetracarboxylic dianhydride and a long-chain hydrocarbyl aminoalcohol.

  14. Biobased lubricant additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fully biobased lubricants are those formulated using all biobased ingredients, i.e. biobased base oils and biobased additives. Such formulations provide the maximum environmental, safety, and economic benefits expected from a biobased product. Currently, there are a number of biobased base oils that...

  15. Computability-theoretic learning complexity.

    PubMed

    Case, John; Kötzing, Timo

    2012-07-28

    Initially discussed are some of Alan Turing's wonderfully profound and influential ideas about mind and mechanism-including regarding their connection to the main topic of the present study, which is within the field of computability-theoretic learning theory. Herein is investigated the part of this field concerned with the algorithmic, trial-and-error inference of eventually correct programs for functions from their data points. As to the main content of this study: in prior papers, beginning with the seminal work by Freivalds et al. in 1995, the notion of intrinsic complexity is used to analyse the learning complexity of sets of functions in a Gold-style learning setting. Herein are pointed out some weaknesses of this notion. Offered is an alternative based on epitomizing sets of functions-sets that are learnable under a given learning criterion, but not under other criteria that are not at least as powerful. To capture the idea of epitomizing sets, new reducibility notions are given based on robust learning (closure of learning under certain sets of computable operators). Various degrees of epitomizing sets are characterized as the sets complete with respect to corresponding reducibility notions! These characterizations also provide an easy method for showing sets to be epitomizers, and they are then employed to prove several sets to be epitomizing. Furthermore, a scheme is provided to generate easily very strong epitomizers for a multitude of learning criteria. These strong epitomizers are the so-called self-learning sets, previously applied by Case & Kötzing in 2010. These strong epitomizers can be easily generated and employed in a myriad of settings to witness with certainty the strict separation in learning power between the criteria so epitomized and other not as powerful criteria!

  16. Theoretical Study on Standing Wave Thermoacoustic Engine

    NASA Astrophysics Data System (ADS)

    Kalra, S.; Desai, K. P.; Naik, H. B.; Atrey, M. D.

    Applications of thermoacoustic engines are not limited to driving pulse tube cryocoolers. The performance of a thermoacoustic engine is governed by various design parameters like type of resonator, stack geometry, frequency, type of working gas etc. and various operating parameters like heat input, charging pressure etc. It is very important to arrive at an optimum configuration of the engine for which a theoretical model is required. In the present work, a theoretical analysis, based on linear acoustic theory of a standing wave type half wavelength thermoacoustic engine is carried out using DeltaEC software. The system dimensions like length of resonator, stack, hot and cold heat exchangers are fixed with a helium-argon mixture as the working gas and a parallel plate type stack. Later on, two plate spacings, corresponding to helium-argon mixture and nitrogen gas, are used for carrying out analysis with helium, argon, nitrogen, carbon dioxide and helium-argon mixture as working gases of the system. The effect of charging pressure on the performance of the system is studied in terms of resonating frequency, onset temperature, pressure amplitude, acoustic power and efficiency. The conclusions derived from the analysis are reported in the paper.

  17. Working Mothers

    MedlinePlus

    ... for their child when child care arrangements have broken down, or to take their child to necessary appointments. When to Return to Work A woman’s decision to return to work must take into account her own needs as well as those of her family. If you are considering returning to work, try ...

  18. Vinyl capped addition polyimides

    NASA Technical Reports Server (NTRS)

    Vannucci, Raymond D. (Inventor); Malarik, Diane C. (Inventor); Delvigs, Peter (Inventor)

    1991-01-01

    Polyimide resins (PMR) are generally useful where high strength and temperature capabilities are required (at temperatures up to about 700 F). Polyimide resins are particularly useful in applications such as jet engine compressor components, for example, blades, vanes, air seals, air splitters, and engine casing parts. Aromatic vinyl capped addition polyimides are obtained by reacting a diamine, an ester of tetracarboxylic acid, and an aromatic vinyl compound. Low void materials with improved oxidative stability when exposed to 700 F air may be fabricated as fiber reinforced high molecular weight capped polyimide composites. The aromatic vinyl capped polyimides are provided with a more aromatic nature and are more thermally stable than highly aliphatic, norbornenyl-type end-capped polyimides employed in PMR resins. The substitution of aromatic vinyl end-caps for norbornenyl end-caps in addition polyimides results in polymers with improved oxidative stability.

  19. Tackifier for addition polyimides

    NASA Technical Reports Server (NTRS)

    Butler, J. M.; St.clair, T. L.

    1980-01-01

    A modification to the addition polyimide, LaRC-160, was prepared to improve tack and drape and increase prepeg out-time. The essentially solventless, high viscosity laminating resin is synthesized from low cost liquid monomers. The modified version takes advantage of a reactive, liquid plasticizer which is used in place of solvent and helps solve a major problem of maintaining good prepeg tack and drape, or the ability of the prepeg to adhere to adjacent plies and conform to a desired shape during the lay up process. This alternate solventless approach allows both longer life of the polymer prepeg and the processing of low void laminates. This approach appears to be applicable to all addition polyimide systems.

  20. Electrophilic addition of astatine

    SciTech Connect

    Norseev, Yu.V.; Vasaros, L.; Nhan, D.D.; Huan, N.K.

    1988-03-01

    It has been shown for the first time that astatine is capable of undergoing addition reactions to unsaturated hydrocarbons. A new compound of astatine, viz., ethylene astatohydrin, has been obtained, and its retention numbers of squalane, Apiezon, and tricresyl phosphate have been found. The influence of various factors on the formation of ethylene astatohydrin has been studied. It has been concluded on the basis of the results obtained that the univalent cations of astatine in an acidic medium is protonated hypoastatous acid.

  1. Functional Generalized Additive Models.

    PubMed

    McLean, Mathew W; Hooker, Giles; Staicu, Ana-Maria; Scheipl, Fabian; Ruppert, David

    2014-01-01

    We introduce the functional generalized additive model (FGAM), a novel regression model for association studies between a scalar response and a functional predictor. We model the link-transformed mean response as the integral with respect to t of F{X(t), t} where F(·,·) is an unknown regression function and X(t) is a functional covariate. Rather than having an additive model in a finite number of principal components as in Müller and Yao (2008), our model incorporates the functional predictor directly and thus our model can be viewed as the natural functional extension of generalized additive models. We estimate F(·,·) using tensor-product B-splines with roughness penalties. A pointwise quantile transformation of the functional predictor is also considered to ensure each tensor-product B-spline has observed data on its support. The methods are evaluated using simulated data and their predictive performance is compared with other competing scalar-on-function regression alternatives. We illustrate the usefulness of our approach through an application to brain tractography, where X(t) is a signal from diffusion tensor imaging at position, t, along a tract in the brain. In one example, the response is disease-status (case or control) and in a second example, it is the score on a cognitive test. R code for performing the simulations and fitting the FGAM can be found in supplemental materials available online.

  2. Is working memory training effective?

    PubMed

    Shipstead, Zach; Redick, Thomas S; Engle, Randall W

    2012-07-01

    Working memory (WM) is a cognitive system that strongly relates to a person's ability to reason with novel information and direct attention to goal-relevant information. Due to the central role that WM plays in general cognition, it has become the focus of a rapidly growing training literature that seeks to affect broad cognitive change through prolonged training on WM tasks. Recent work has suggested that the effects of WM training extend to general fluid intelligence, attentional control, and reductions in symptoms of ADHD. We present a theoretically motivated perspective of WM and subsequently review the WM training literature in light of several concerns. These include (a) the tendency for researchers to define change to abilities using single tasks, (b) inconsistent use of valid WM tasks, (c) no-contact control groups, and (d) subjective measurement of change. The literature review highlights several findings that warrant further research but ultimately concludes that there is a need to directly demonstrate that WM capacity increases in response to training. Specifically, we argue that transfer of training to WM must be demonstrated using a wider variety of tasks, thus eliminating the possibility that results can be explained by task specific learning. Additionally, we express concern that many of the most promising results (e.g., increased intelligence) cannot be readily attributed to changes in WM capacity. Thus, a critical goal for future research is to uncover the mechanisms that lead to transfer of training.

  3. Theoretical Issues of Cluster Pattern Interfaces

    NASA Astrophysics Data System (ADS)

    Barneva, Reneta P.; Brimkov, Valentin E.; Kanev, Kamen K.

    Since the 80s, when the computer mouse was first invented, point-and-click functionality became widely adopted, in particular, for work with images and GUIs. It would be useful to provide such functionality for printed materials, as well. A direct point-and-click functionality should not require tablet-like devices, but should rather use an embedded marking which defines a coordinate system within the image. An original approach and related technology for direct interface, known as Cluster Pattern Interface (CLUSPI), was proposed [12]. It is based on an unobtrusive layer of the image defining a coordinate system, a camera-based pointing device, and decoding software. CLUSPI technology was invented and patented by one of the authors of this paper. Here we present the theoretical (mathematical) foundations of the methods developed. We also describe some theoretical challenges and propose solutions to them.

  4. Rear projection screens: a theoretical analysis.

    PubMed

    Herrick, R B

    1968-05-01

    The increasing use of rear projection screens has brought about the need for a better understanding of their performance limits based on an analytical model which relates the physical and optical properties of the screen. A theoretical model is developed based on the Mie theory of light scattering, and a general discussion is given of the optical and viewing properties of rear projection screens, using an operational terminology. Basic light scattering data are used to calculate relations between such optical properties as screen brightness, axial gain, uniformity, efficiency, color fidelity, and ambient light sensitivity from such physical parameters as scattering particle size and number density, and relative refractive index of the scattering particles. Data from experimental investigations of volume scattering materials fabricated by Corning Glass Works are found to be in good agreement with the theoretical calculations. PMID:20068680

  5. Work organization and the health of bank employees.

    PubMed

    Silva, Juliana Lemos; Navarro, Vera Lucia

    2012-01-01

    The Brazilian banking sector has undergone an intense restructuring process and taken a leading position in the incorporation of new technologies and organizational innovations. Computerization in the industry, in association with forms of work organization, has resulted in changes that reflect on the workers' health. Based on the theoretical and methodological frameworks of historical and dialectical materialism, this qualitative study investigates the work conditions of bank employees in order to identify the extent to which changes in work organization interfere with these workers' health. Data were collected through interviews held with 11 bank employees. In addition to physical sickening due to occupational diseases directly related to work intensification, the results also show an increased incidence of mental suffering and a feeling of loss of professional identity. Work-related frustration, instability and concerns related to psychological pressure resulting from the need to achieve goals predominated in the reports. PMID:22699722

  6. Work organization and the health of bank employees.

    PubMed

    Silva, Juliana Lemos; Navarro, Vera Lucia

    2012-01-01

    The Brazilian banking sector has undergone an intense restructuring process and taken a leading position in the incorporation of new technologies and organizational innovations. Computerization in the industry, in association with forms of work organization, has resulted in changes that reflect on the workers' health. Based on the theoretical and methodological frameworks of historical and dialectical materialism, this qualitative study investigates the work conditions of bank employees in order to identify the extent to which changes in work organization interfere with these workers' health. Data were collected through interviews held with 11 bank employees. In addition to physical sickening due to occupational diseases directly related to work intensification, the results also show an increased incidence of mental suffering and a feeling of loss of professional identity. Work-related frustration, instability and concerns related to psychological pressure resulting from the need to achieve goals predominated in the reports.

  7. Theoretical Foundations of Learning Communities

    ERIC Educational Resources Information Center

    Jessup-Anger, Jody E.

    2015-01-01

    This chapter describes the historical and contemporary theoretical underpinnings of learning communities and argues that there is a need for more complex models in conceptualizing and assessing their effectiveness.

  8. Theory of atomic additivity in molecular hyperpolizabilities

    NASA Technical Reports Server (NTRS)

    Baird, James K.

    1987-01-01

    Hyperpolarizability is a function of frequency. This is called dispersion. Because of the Kramers-Kronig relations, researchers expect that a material that is dispersing light is also absorbing it. Where there is both dispersion and absorption, the molecular polarizabilities are complex functions of the frequency. This led researchers to consider atomic additivity in both the real and imaginary parts of the ordinary and hyperpolarizabilities. This effort is desirable not only from a theoretical point of view, but also because of the existence of a large body of complex refractive index data, which may be used to test the additivity principle with the complex valued ordinary dipole polarizability.

  9. Effort-reward imbalance at work and cardiovascular diseases.

    PubMed

    Siegrist, Johannes

    2010-01-01

    Working conditions and employment arrangements make a significant contribution to the burden of cardiovascular disease, in particular in modern societies where mental and emotional demands and threats are becoming widespread. Occupational research has identified health-adverse features of modern work with the help of theoretical models. One such model, effort-reward imbalance, has been developed by this author and his group and has been widely tested in epidemiological and experimental studies. The model claims that stressful experience at work is elicited by a lack of reciprocity between efforts spent at work and rewards received in return, where rewards include money, promotion prospects, job security, and esteem. Results demonstrate elevated risks of coronary heart disease among employees exposed to effort-reward imbalance. Moreover, in ambulatory and experimental investigations, elevated heart rate and blood pressure and altered secretion of stress hormones were observed under these conditions. Although additional scientific evidence is needed, available findings call for practical measures towards improving quality of work, most importantly at the level of single companies and organisations. This conclusion is supported by first results from intervention studies that are guided by this theoretical approach. In view of the burden of cardiovascular disease attributable to unfavourable working conditions, such efforts are well justified and need to be extended in order to promote healthy work.

  10. Theoretical investigation on a general class of 2D quasicrystals with the rectangular projection method

    NASA Astrophysics Data System (ADS)

    Yue, Yang-Yang; Lu, Rong-er; Yang, Bo; Huang, Huang; Hong, Xu-Hao; Zhang, Chao; Qin, Yi-Qiang; Zhu, Yong-Yuan

    2016-10-01

    We take a theoretical investigation on the reciprocal property of a class of 2D nonlinear photonic quasicrystal proposed by Lifshitz et al. in PRL 95, 133901 (2005). Using the rectangular projection method, the analytical expression for the Fourier spectrum of the quasicrystal structure is obtained explicitly. It is interesting to find that the result has a similar form to the corresponding expression of the well-known 1D Fibonacci lattice. In addition, we predict a further extension of the result to higher dimensions. This work is of practical importance for the photonic device design in nonlinear optical conversion progresses.

  11. Theoretical and experimental studies of the stability of drug-drug interact

    NASA Astrophysics Data System (ADS)

    Soares, Monica F. R.; Alves, Lariza D. S.; Nadvorny, Daniela; Soares-Sobrinho, José L.; Rolim-Neto, Pedro J.

    2016-11-01

    Several factors can intervene in the molecular properties and consequently in the stability of drugs. The molecular complexes formation often occur due to favor the formation of hydrogen bonds, leading the system to configuration more energy stable. This work we aim to investigate through theoretical and experimental methods the relation between stability and properties of molecular complexes the molecular complex formed between the drugs, efavirenz (EFV), lamivudine (3TC) and zidovudine (AZT). With this study was possible determining the most stable complex formed between the compounds evaluated. In addition the energy and structural properties of the complex formed in relation to its individual components allowed us to evaluate the stability of the same.

  12. Performance Boosting Additive

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Mainstream Engineering Corporation was awarded Phase I and Phase II contracts from Goddard Space Flight Center's Small Business Innovation Research (SBIR) program in early 1990. With support from the SBIR program, Mainstream Engineering Corporation has developed a unique low cost additive, QwikBoost (TM), that increases the performance of air conditioners, heat pumps, refrigerators, and freezers. Because of the energy and environmental benefits of QwikBoost, Mainstream received the Tibbetts Award at a White House Ceremony on October 16, 1997. QwikBoost was introduced at the 1998 International Air Conditioning, Heating, and Refrigeration Exposition. QwikBoost is packaged in a handy 3-ounce can (pressurized with R-134a) and will be available for automotive air conditioning systems in summer 1998.

  13. Sewage sludge additive

    NASA Technical Reports Server (NTRS)

    Kalvinskas, J. J.; Mueller, W. A.; Ingham, J. D. (Inventor)

    1980-01-01

    The additive is for a raw sewage treatment process of the type where settling tanks are used for the purpose of permitting the suspended matter in the raw sewage to be settled as well as to permit adsorption of the dissolved contaminants in the water of the sewage. The sludge, which settles down to the bottom of the settling tank is extracted, pyrolyzed and activated to form activated carbon and ash which is mixed with the sewage prior to its introduction into the settling tank. The sludge does not provide all of the activated carbon and ash required for adequate treatment of the raw sewage. It is necessary to add carbon to the process and instead of expensive commercial carbon, coal is used to provide the carbon supplement.

  14. Perspectives on Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Bourell, David L.

    2016-07-01

    Additive manufacturing (AM) has skyrocketed in visibility commercially and in the public sector. This article describes the development of this field from early layered manufacturing approaches of photosculpture, topography, and material deposition. Certain precursors to modern AM processes are also briefly described. The growth of the field over the last 30 years is presented. Included is the standard delineation of AM technologies into seven broad categories. The economics of AM part generation is considered, and the impacts of the economics on application sectors are described. On the basis of current trends, the future outlook will include a convergence of AM fabricators, mass-produced AM fabricators, enabling of topology optimization designs, and specialization in the AM legal arena. Long-term developments with huge impact are organ printing and volume-based printing.

  15. Sarks as additional fermions

    NASA Astrophysics Data System (ADS)

    Agrawal, Jyoti; Frampton, Paul H.; Jack Ng, Y.; Nishino, Hitoshi; Yasuda, Osamu

    1991-03-01

    An extension of the standard model is proposed. The gauge group is SU(2) X ⊗ SU(3) C ⊗ SU(2) S ⊗ U(1) Q, where all gauge symmetries are unbroken. The colour and electric charge are combined with SU(2) S which becomes strongly coupled at approximately 500 GeV and binds preons to form fermionic and vector bound states. The usual quarks and leptons are singlets under SU(2) X but additional fermions, called sarks. transform under it and the electroweak group. The present model explains why no more than three light quark-lepton families can exist. Neutral sark baryons, called narks, are candidates for the cosmological dark matter having the characteristics designed for WIMPS. Further phenomenological implications of sarks are analyzed i including electron-positron annihilation. Z 0 decay, flavor-changing neutral currents. baryon-number non-conservation, sarkonium and the neutron electric dipole moment.

  16. Theoretical molecular studies of astrophysical interest

    NASA Technical Reports Server (NTRS)

    Flynn, George

    1991-01-01

    When work under this grant began in 1974 there was a great need for state-to-state collisional excitation rates for interstellar molecules observed by radio astronomers. These were required to interpret observed line intensities in terms of local temperatures and densities, but, owing to lack of experimental or theoretical values, estimates then being used for this purpose ranged over several orders of magnitude. A problem of particular interest was collisional excitation of formaldehyde; Townes and Cheung had suggested that the relative size of different state-to-state rates (propensity rules) was responsible for the anomalous absorption observed for this species. We believed that numerical molecular scattering techniques (in particular the close coupling or coupled channel method) could be used to obtain accurate results, and that these would be computationally feasible since only a few molecular rotational levels are populated at the low temperatures thought to prevail in the observed regions. Such calculations also require detailed knowledge of the intermolecular forces, but we thought that those could also be obtained with sufficient accuracy by theoretical (quantum chemical) techniques. Others, notably Roy Gordon at Harvard, had made progress in solving the molecular scattering equations, generally using semi-empirical intermolecular potentials. Work done under this grant generalized Gordon's scattering code, and introduced the use of theoretical interaction potentials obtained by solving the molecular Schroedinger equation. Earlier work had considered only the excitation of a diatomic molecule by collisions with an atom, and we extended the formalism to include excitation of more general molecular rotors (e.g., H2CO, NH2, and H2O) and also collisions of two rotors (e.g., H2-H2).

  17. Theoretical plurality and pluralism in psychoanalytic practice.

    PubMed

    Jiménez, Juan Pablo

    2008-06-01

    The author begins by characterizing the present situation of psychoanalysis as one of increasing theoretical and practical diversity. The aim of this paper is to consider in depth the impact of theoretical plurality on clinical practice. After noting that the analyst has much more than evenly suspended attention in his(2)mind as he works with his patient in a session, the author reviews both older and more recent contributions on what the analyst has in his mind when working with a patient. He suggests that the subject has been addressed mainly from a single-person perspective. In this connection, and on the basis of clinical material, he attempts to show how, against the background of the 'implicit use of explicit theories', an ongoing process of decision-making that is co-determined by the patient's action and reaction takes place in the analyst's mind. In his analysis of a session, the author introduces the concepts of theoretical reason and practical reason, and contends that, whatever theories the analyst may have implicitly or explicitly in his mind, they ultimately yield to practical reasons. Pursuing the same line of thought, he describes validation in the clinical context as a single, wide-ranging, continuous process of social and linguistic co-construction of the intersubjective reality between patient and analyst. This process includes mutual aspects of observation and of communicative and pragmatic validation. In conclusion, he suggests that the figure of the craftsman is an appropriate description of the analyst in this conception of his work.

  18. Experimental and theoretical analysis of a Solar Liquid Piston Pump

    SciTech Connect

    Murphy, C.L.; Brew-Hammoud, A.

    1985-08-01

    The Solar Liquid Piston Pump (SLPP) is driven by oscillations of an enclosed column of liquid Freon 113. Cyclic evaporation and condensation from heating and cooling coils at the top of the liquid column generate the oscillations. The frequency and amplitude of the oscillations are enhanced by momentum forces in the inlet, outlet, and working tubes. Three geometrically different experimental models of a SLPP have been tested. To optimize the performance of the SLPP, a theoretical model was required to account for the large number of interdependent parametres that could be varied. A semiemperical time-incremented computer model was developed. A theoretical cycle was assumed and the heat transfer and fluid friction coefficient adjusted, within reasonable limits, so that the theoretical pressurevolume diagrams agreed closely with experimental ones. Input parameters were then varied for the theoretical model and compared to experimental results available. The theoretical model successfully predicted performance trends of the SLPP.

  19. Work-Sharing: Panacea or Palliative?

    ERIC Educational Resources Information Center

    Dawkins, Peter J.

    1983-01-01

    Recently, high unemployment and a high perceived rate of technological change have created interest in work-sharing. Definitions of different types of work-sharing and theoretical and practical issues related to work-sharing are covered. Work-sharing is not necessarily a panacea, but it does show the potential to help. (Author/IS)

  20. Working Knowledge.

    ERIC Educational Resources Information Center

    Beckett, David

    The resurgence of "lifelong learning" has renewed consideration of the nature of "working knowledge." Lifelong learning has many aspects, including construction and distribution of individuals' very self-hood, educational institutions' role in capturing informal experiences, and the juggling required between family and work-based responsibilities.…

  1. Projects Work!

    ERIC Educational Resources Information Center

    Textor, Martin R.

    2005-01-01

    The great educational value of projects is emphasized by contrasting negative aspects of the life of today's children with the goals of project work. This is illustrated by a project "Shopping." It is shown what children are learning in such projects and what the advantages of project work are. Relevant topic areas, criteria for selecting a…

  2. A quantum theoretical study of polyimides

    NASA Technical Reports Server (NTRS)

    Burke, Luke A.

    1987-01-01

    One of the most important contributions of theoretical chemistry is the correct prediction of properties of materials before any costly experimental work begins. This is especially true in the field of electrically conducting polymers. Development of the Valence Effective Hamiltonian (VEH) technique for the calculation of the band structure of polymers was initiated. The necessary VEH potentials were developed for the sulfur and oxygen atoms within the particular molecular environments and the explanation explored for the success of this approximate method in predicting the optical properties of conducting polymers.

  3. Design Of Theoretically Optimal Thermoacoustic Cooling Device

    NASA Astrophysics Data System (ADS)

    Tisovský, Tomáš; Vít, Tomáš

    2016-03-01

    The aim of this article is to design theoretically optimal thermoacoustic cooling device. The opening chapter gives the reader brief introduction to thermoacoustic, specializing in the thermoacoustic principle in refrigerator regime. Subsequent part of the article aims to explain the principle on which thermoacoustic is simulated in DeltaEC. Numbers of executed numerical simulations are listed and the resulting thermoacoustic cooling device design is presented along with its main operation characteristics. In conclusion, recommendations for future experimental work are given and the results are discussed.

  4. Recent Theoretical Studies On Excitation and Recombination

    NASA Technical Reports Server (NTRS)

    Pradhan, Anil K.

    2000-01-01

    New advances in the theoretical treatment of atomic processes in plasmas are described. These enable not only an integrated, unified, and self-consistent treatment of important radiative and collisional processes, but also large-scale computation of atomic data with high accuracy. An extension of the R-matrix work, from excitation and photoionization to electron-ion recombination, includes a unified method that subsumes both the radiative and the di-electronic recombination processes in an ab initio manner. The extensive collisional calculations for iron and iron-peak elements under the Iron Project are also discussed.

  5. [Experimental and theoretical high energy physics program

    SciTech Connect

    Finley, J.; Gaidos, J.A.; Loeffler, F.J.; McIlwain, R.L.; Miller, D.H.; Palfrey, T.R.; Shibata, E.I.; Shipsey, I.P.

    1993-04-01

    Experimental and theoretical high-energy physics research at Purdue is summarized in a number of reports. Subjects treated include the following: the CLEO experiment for the study of heavy flavor physics; gas microstrip detectors; particle astrophysics; affine Kac{endash}Moody algebra; nonperturbative mass bounds on scalar and fermion systems due to triviality and vacuum stability constraints; resonance neutrino oscillations; e{sup +}e{sup {minus}} collisions at CERN; {bar p}{endash}p collisions at FNAL; accelerator physics at Fermilab; development work for the SDC detector at SSC; TOPAZ; D-zero physics; physics beyond the standard model; and the Collider Detector at Fermilab. (RWR)

  6. Theoretical photoabsorption spectra of Ar n+ clusters

    NASA Astrophysics Data System (ADS)

    Doltsinis, Nikos L.; Knowles, Peter J.

    2000-08-01

    The photoabsorption spectra of selected Ar n+ clusters ( n=7, 8, 17, 19, 23) have been investigated theoretically using an extended Diatomics-in-Molecules approach including induced dipole - induced dipole and spin-orbit coupling interaction effects. Our calculations at 0 K confirm the experimentally observed spectral red-shift of the visible photoabsorption peak in the region 15< n<20 [Levinger et al., J. Chem. Phys. 89 (1988) 5654]. Furthermore, we have been able to reproduce the additional red-shift measured for 7⩽ n⩽9 [Haberland et al., Phys. Rev. Lett. 67 (1991) 3290] by carrying out finite temperature Monte Carlo simulations.

  7. KADATH: A spectral solver for theoretical physics

    SciTech Connect

    Grandclement, Philippe

    2010-05-01

    KADATH is a library that implements spectral methods in a very modular manner. It is designed to solve a wide class of problems that arise in the context of theoretical physics. Several types of coordinates are implemented and additional geometries can be easily encoded. Partial differential equations of various types are discretized by means of spectral methods. The resulting system is solved using a Newton-Raphson iteration. Doing so, KADATH is able to deal with strongly non-linear situations. The algorithms are validated by applying the library to four different problems of contemporary physics, in the fields of gauge field theory and general relativity.

  8. Role Resources and Work-Family Enrichment: The Role of Work Engagement

    ERIC Educational Resources Information Center

    Siu, Oi-ling; Lu, Jia-fang; Brough, Paula; Lu, Chang-qin; Bakker, Arnold B.; Kalliath, Thomas; O'Driscoll, Michael; Phillips, David R.; Chen, Wei-qing; Lo, Danny; Sit, Cindy; Shi, Kan

    2010-01-01

    This article proposes a theoretical model of work-family enrichment and tests the mediating role of work engagement. The inclusion of work engagement extends prior research on work-family interface, and allows for examination of the effects of role resources (job resources, family support) on work-family enrichment. A two-wave survey was conducted…

  9. Exploring Job Satisfaction of Nursing Faculty: Theoretical Approaches.

    PubMed

    Wang, Yingchen; Liesveld, Judy

    2015-01-01

    The Future of Nursing report identified the shortage of nursing faculty as 1 of the barriers to nursing education. In light of this, it is becoming increasingly important to understand the work-life of nursing faculty. The current research focused on job satisfaction of nursing faculty from 4 theoretical perspectives: human capital theory, which emphasizes the expected monetary and nonmonetary returns for any career choices; structural theory, which emphasizes the impact of institutional features on job satisfaction; positive extrinsic environment by self-determination theory, which asserts that a positive extrinsic environment promotes competency and effective outcomes at work; and psychological theory, which emphasizes the proposed relationship between job performance and satisfaction. In addition to the measures for human capital theory, institutional variables (from structural theory and self-determination theory), and productivity measures (from psychological theory), the authors also selected sets of variables for personal characteristics to investigate their effects on job satisfaction. The results indicated that variables related to human capital theory, especially salary, contributed the most to job satisfaction, followed by those related to institutional variables. Personal variables and productivity variables as a whole contributed as well. The only other variable with marginal significance was faculty's perception of institutional support for teaching. PMID:26653042

  10. Theoretical resources for a globalised bioethics.

    PubMed

    Verkerk, Marian A; Lindemann, Hilde

    2011-02-01

    In an age of global capitalism, pandemics, far-flung biobanks, multinational drug trials and telemedicine it is impossible for bioethicists to ignore the global dimensions of their field. However, if they are to do good work on the issues that globalisation requires of them, they need theoretical resources that are up to the task. This paper identifies four distinct understandings of 'globalised' in the bioethics literature: (1) a focus on global issues; (2) an attempt to develop a universal ethical theory that can transcend cultural differences; (3) an awareness of how bioethics itself has expanded, with new centres and journals emerging in nearly every corner of the globe; (4) a concern to avoid cultural imperialism in encounters with other societies. Each of these approaches to globalisation has some merit, as will be shown. The difficulty with them is that the standard theoretical tools on which they rely are not designed for cross-cultural ethical reflection. As a result, they leave important considerations hidden. A set of theoretical resources is proposed to deal with the moral puzzles of globalisation. Abandoning idealised moral theory, a normative framework is developed that is sensitive enough to account for differences without losing the broader context in which ethical issues arise. An empirically nourished, self-reflexive, socially inquisitive, politically critical and inclusive ethics allows bioethicists the flexibility they need to pick up on the morally relevant particulars of this situation here without losing sight of the broader cultural contexts in which it all takes place. PMID:21109698

  11. Theoretical resources for a globalised bioethics.

    PubMed

    Verkerk, Marian A; Lindemann, Hilde

    2011-02-01

    In an age of global capitalism, pandemics, far-flung biobanks, multinational drug trials and telemedicine it is impossible for bioethicists to ignore the global dimensions of their field. However, if they are to do good work on the issues that globalisation requires of them, they need theoretical resources that are up to the task. This paper identifies four distinct understandings of 'globalised' in the bioethics literature: (1) a focus on global issues; (2) an attempt to develop a universal ethical theory that can transcend cultural differences; (3) an awareness of how bioethics itself has expanded, with new centres and journals emerging in nearly every corner of the globe; (4) a concern to avoid cultural imperialism in encounters with other societies. Each of these approaches to globalisation has some merit, as will be shown. The difficulty with them is that the standard theoretical tools on which they rely are not designed for cross-cultural ethical reflection. As a result, they leave important considerations hidden. A set of theoretical resources is proposed to deal with the moral puzzles of globalisation. Abandoning idealised moral theory, a normative framework is developed that is sensitive enough to account for differences without losing the broader context in which ethical issues arise. An empirically nourished, self-reflexive, socially inquisitive, politically critical and inclusive ethics allows bioethicists the flexibility they need to pick up on the morally relevant particulars of this situation here without losing sight of the broader cultural contexts in which it all takes place.

  12. Additive lattice kirigami

    PubMed Central

    Castle, Toen; Sussman, Daniel M.; Tanis, Michael; Kamien, Randall D.

    2016-01-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes. PMID:27679822

  13. Additive lattice kirigami

    PubMed Central

    Castle, Toen; Sussman, Daniel M.; Tanis, Michael; Kamien, Randall D.

    2016-01-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes.

  14. [Wet work].

    PubMed

    Kieć-Swierczyńska, Marta; Chomiczewska, Dorota; Krecisz, Beata

    2010-01-01

    Wet work is one of the most important risk factors of occupational skin diseases. Exposure of hands to the wet environment for more than 2 hours daily, wearing moisture-proof protective gloves for a corresponding period of time or necessity to wash hands frequently lead to the disruption of epidermal stratum corneum, damage to skin barrier function and induction of irritant contact dermatitis. It may also promote penetration of allergens into the skin and increase the risk of sensitization to occupational allergens. Exposure to wet work plays a significant role in occupations, such as hairdressers and barbers, nurses and other health care workers, cleaning staff, food handlers and metalworkers. It is more common among women because many occupations involving wet work are female-dominated. The incidence of wet-work-induced occupational skin diseases can be reduced by taking appropriate preventive measures. These include identification of high-risk groups, education of workers, organization of work enabling to minimize the exposure to wet work, use of personal protective equipment and skin care after work.

  15. A theoretical and experimental study of coplanar waveguide shunt stubs

    NASA Technical Reports Server (NTRS)

    Dib, Nihad I.; Ponchak, George E.; Katehi, Linda P. B.

    1993-01-01

    A comprehensive theoretical and experimental study of straight and bent coplanar waveguide (CPW) shunt stubs is presented. In the theoretical analysis, the CPW is assumed to be inside a cavity while, the experiments are performed on open structures. For the analysis of CPW discontinuities with air-bridges, a hybrid technique was developed which was validated through extensive theoretical and experimental comparisons. The effect of the cavity resonances on the behavior of the stubs with and without air-bridges is investigated. In addition, the encountered radiation loss due to the discontinuities is evaluated experimentally.

  16. A career in theoretical physics

    NASA Astrophysics Data System (ADS)

    Anderson, P. W.

    -- 49. Chemical pseudopotentials -- 50. Spin glass Hamiltonians: a bridge between biology, statistical mechanics and computer science in Emerging Syntheses in Science -- 51. Measurement in quantum theory and the problem of complex systems in The Lessons of Quantum Theory -- 52. It's not over till the fat lady sings -- 53. Spin Glass I: a scaling law rescued. Spin glass II: is there a phase transition? Spin glass III: theory raises its head. Spin Glass IV: glimmerings of trouble. Spin glass V: real power brought to bear. Spin glass VI: spin glass as cornucopia. Spin glass VII: spin glass as paradigm -- 54. Epilogue in Valence Instabilities and Related Narrow-band Phenomena -- 55. Present status of theory: l/N approach n Proc. of 1983 NATO/CAP Inst. "Moment Formation in Solids" -- 56. The problem of fluctuating valence in f-electron metals in Windsurfing in the Fermi sea -- 57. Gutzwiller-Hubbard lattice-gas model with variable density: application to normal liquid [symbol]He (with D. Vollhardt and P. Wöffle) -- 58. Some ideas on the Aesthetics of Science lecture given at the 50th Anniversary seminar of the Faculty of Science and Technology, Keio University, Japan -- 59. Theoretical paradigms for the Sciences of Complexity Nishima Memorial Lecture, Department of Physics, Keio University -- 60. 50 years of the Mott phenomenon: insulators, magnets, solids, and superconductors as aspects of strong-repulsion theory in Frontiers and Borderlines in Many-Particle Physics -- 61. Theories of Fullerene T[symbol]'s which will not work -- 62. The Reverend Thomas Bayes, needles in haystacks, and the fifth force -- 63. The eightfold way to the theory of complexity: a prologue in Complexity -- 64. Magnetic field induced confinement in strongly correlated anisotropic materials (with S. P. Strong and D. G. Clarke) -- 65. Physics: the opening to complexity -- 66. Beyond chaos: singular distributions and power laws -- 67. Essay review - science: a 'dappled world' or a 'seamless web'? -- 68

  17. Does "Social Work Abstracts" Work?

    ERIC Educational Resources Information Center

    Holden, Gary; Barker, Kathleen; Covert-Vail, Lucinda; Rosenberg, Gary; Cohen, Stephanie A.

    2008-01-01

    Objective: The current study seeks to provide estimates of the adequacy of journal coverage in the Social Work Abstracts (SWA) database. Method: A total of 23 journals listed in the Journal Citation Reports social work category during the 1997 to 2005 period were selected for study. Issue-level coverage estimates were obtained for SWA and…

  18. Does Work Experience Actually Work?

    ERIC Educational Resources Information Center

    Field, John

    2012-01-01

    As unemployment levels rise, so education and training move into the policy spotlight. For the government, this is a very uncomfortable place to be right now. A number of large companies have withdrawn from the flagship Work Programme--under which jobseekers are invited to take up unpaid work placements of between two and eight weeks--amid…

  19. Is New Work Good Work?

    ERIC Educational Resources Information Center

    Westwood, Andy

    Some new work is good work. Quality is ultimately defined by the individual. However, these perceptions are inevitably colored by the circumstances in which people find themselves, by the time, place, and wide range of motivations for having to do a particular job in the first place. One person's quality may be another's purgatory and vice versa.…

  20. Team Work.

    ERIC Educational Resources Information Center

    Frank, David

    1999-01-01

    Explains how a team cleaning approach can be cost-effective and efficient means of school maintenance. Assigning staffing responsibilities and work schedules are addressed and the advantages of using a team system are explained. (GR)

  1. Working Parents

    MedlinePlus

    ... as the family's values, fathers may assume more responsibility for child care and housework than has traditionally ... and fatigue as they try to juggle their responsibilities at home and at work. If you are ...

  2. Theoretical analysis of BER performance of nonlinearly amplified FBMC/OQAM and OFDM signals

    NASA Astrophysics Data System (ADS)

    Bouhadda, Hanen; Shaiek, Hmaied; Roviras, Daniel; Zayani, Rafik; Medjahdi, Yahia; Bouallegue, Ridha

    2014-12-01

    In this paper, we introduce an analytical study of the impact of high-power amplifier (HPA) nonlinear distortion (NLD) on the bit error rate (BER) of multicarrier techniques. Two schemes of multicarrier modulations are considered in this work: the classical orthogonal frequency division multiplexing (OFDM) and the filter bank-based multicarrier using offset quadrature amplitude modulation (FBMC/OQAM), including different HPA models. According to Bussgang's theorem, the in-band NLD is modeled as a complex gain in addition to an independent noise term for a Gaussian input signal. The BER performance of OFDM and FBMC/OQAM modulations, transmitting over additive white Gaussian noise (AWGN) and Rayleigh fading channels, is theoretically investigated and compared to simulation results. For simple HPA models, such as the soft envelope limiter, it is easy to compute the BER theoretical expression. However, for other HPA models or for real measured HPA, BER derivation is generally intractable. In this paper, we propose a general method based on a polynomial fitting of the HPA characteristics and we give theoretical expressions for the BER for any HPA model.

  3. Theoretical Consolidation of Acoustic Dissipation

    NASA Technical Reports Server (NTRS)

    Casiano, M. J.; Zoladz, T. F.

    2012-01-01

    In many engineering problems, the effects of dissipation can be extremely important. Dissipation can be represented by several parameters depending on the context and the models that are used. Some examples of dissipation-related parameters are damping ratio, viscosity, resistance, absorption coefficients, pressure drop, or damping rate. This Technical Memorandum (TM) describes the theoretical consolidation of the classic absorption coefficients with several other dissipation parameters including linearized resistance. The primary goal of this TM is to theoretically consolidate the linearized resistance with the absorption coefficient. As a secondary goal, other dissipation relationships are presented.

  4. Printability of alloys for additive manufacturing.

    PubMed

    Mukherjee, T; Zuback, J S; De, A; DebRoy, T

    2016-01-01

    Although additive manufacturing (AM), or three dimensional (3D) printing, provides significant advantages over existing manufacturing techniques, metallic parts produced by AM are susceptible to distortion, lack of fusion defects and compositional changes. Here we show that the printability, or the ability of an alloy to avoid these defects, can be examined by developing and testing appropriate theories. A theoretical scaling analysis is used to test vulnerability of various alloys to thermal distortion. A theoretical kinetic model is used to examine predisposition of different alloys to AM induced compositional changes. A well-tested numerical heat transfer and fluid flow model is used to compare susceptibilities of various alloys to lack of fusion defects. These results are tested and validated with independent experimental data. The findings presented in this paper are aimed at achieving distortion free, compositionally sound and well bonded metallic parts.

  5. Printability of alloys for additive manufacturing

    PubMed Central

    Mukherjee, T.; Zuback, J. S.; De, A.; DebRoy, T.

    2016-01-01

    Although additive manufacturing (AM), or three dimensional (3D) printing, provides significant advantages over existing manufacturing techniques, metallic parts produced by AM are susceptible to distortion, lack of fusion defects and compositional changes. Here we show that the printability, or the ability of an alloy to avoid these defects, can be examined by developing and testing appropriate theories. A theoretical scaling analysis is used to test vulnerability of various alloys to thermal distortion. A theoretical kinetic model is used to examine predisposition of different alloys to AM induced compositional changes. A well-tested numerical heat transfer and fluid flow model is used to compare susceptibilities of various alloys to lack of fusion defects. These results are tested and validated with independent experimental data. The findings presented in this paper are aimed at achieving distortion free, compositionally sound and well bonded metallic parts. PMID:26796864

  6. Printability of alloys for additive manufacturing

    NASA Astrophysics Data System (ADS)

    Mukherjee, T.; Zuback, J. S.; de, A.; Debroy, T.

    2016-01-01

    Although additive manufacturing (AM), or three dimensional (3D) printing, provides significant advantages over existing manufacturing techniques, metallic parts produced by AM are susceptible to distortion, lack of fusion defects and compositional changes. Here we show that the printability, or the ability of an alloy to avoid these defects, can be examined by developing and testing appropriate theories. A theoretical scaling analysis is used to test vulnerability of various alloys to thermal distortion. A theoretical kinetic model is used to examine predisposition of different alloys to AM induced compositional changes. A well-tested numerical heat transfer and fluid flow model is used to compare susceptibilities of various alloys to lack of fusion defects. These results are tested and validated with independent experimental data. The findings presented in this paper are aimed at achieving distortion free, compositionally sound and well bonded metallic parts.

  7. Printability of alloys for additive manufacturing.

    PubMed

    Mukherjee, T; Zuback, J S; De, A; DebRoy, T

    2016-01-01

    Although additive manufacturing (AM), or three dimensional (3D) printing, provides significant advantages over existing manufacturing techniques, metallic parts produced by AM are susceptible to distortion, lack of fusion defects and compositional changes. Here we show that the printability, or the ability of an alloy to avoid these defects, can be examined by developing and testing appropriate theories. A theoretical scaling analysis is used to test vulnerability of various alloys to thermal distortion. A theoretical kinetic model is used to examine predisposition of different alloys to AM induced compositional changes. A well-tested numerical heat transfer and fluid flow model is used to compare susceptibilities of various alloys to lack of fusion defects. These results are tested and validated with independent experimental data. The findings presented in this paper are aimed at achieving distortion free, compositionally sound and well bonded metallic parts. PMID:26796864

  8. Printability of alloys for additive manufacturing

    DOE PAGES

    Mukherjee, T.; Zuback, J. S.; De, A.; DebRoy, T.

    2016-01-22

    Although additive manufacturing (AM), or three dimensional (3D) printing, provides significant advantages over existing manufacturing techniques, metallic parts produced by AM are susceptible to distortion, lack of fusion defects and compositional changes. Here we show that the printability, or the ability of an alloy to avoid these defects, can be examined by developing and testing appropriate theories. A theoretical scaling analysis is used to test vulnerability of various alloys to thermal distortion. A theoretical kinetic model is used to examine predisposition of different alloys to AM induced compositional changes. A well-tested numerical heat transfer and fluid flow model is usedmore » to compare susceptibilities of various alloys to lack of fusion defects. These results are tested and validated with independent experimental data. Here, the findings presented in this paper are aimed at achieving distortion free, compositionally sound and well bonded metallic parts.« less

  9. Information-theoretic limits of control

    PubMed

    Touchette; Lloyd

    2000-02-01

    Fundamental limits on the controllability of physical systems are discussed in the light of information theory. It is shown that the second law of thermodynamics, when generalized to include information, sets absolute limits to the minimum amount of dissipation required by open-loop control. In addition, an information-theoretic analysis of control systems shows feedback control to be a zero sum game: each bit of information gathered from a dynamical system by a control device can serve to decrease the entropy of that system by at most one bit additional to the reduction of entropy attainable without such information. Consequences for the control of discrete state systems and chaotic maps are discussed. PMID:11017467

  10. Compulsive Working, "Hyperprofessionality" and the Unseen Pleasures of Academic Work

    ERIC Educational Resources Information Center

    Gornall, Lynne; Salisbury, Jane

    2012-01-01

    The paper applies Hoyle's notion of "extended" professionality to modern higher education working. It begins with some of the policy contexts and theoretical perspectives around the structural and professional change experienced by academic staff: changes that have been documented in systematic studies of university life from the 1970s onwards.…

  11. Theoretical Foundations of Learning Environments

    ERIC Educational Resources Information Center

    Jonassen, David H., Ed.; Land, Susan M., Ed.

    1999-01-01

    "Theoretical Foundations of Learning Environments" describes the most contemporary psychological and pedagogical theories that are foundations for the conception and design of open-ended learning environments and new applications of educational technologies. In the past decade, the cognitive revolution of the 60s and 70s has been replaced or…

  12. Asking Research Questions: Theoretical Presuppositions

    ERIC Educational Resources Information Center

    Tenenberg, Josh

    2014-01-01

    Asking significant research questions is a crucial aspect of building a research foundation in computer science (CS) education. In this article, I argue that the questions that we ask are shaped by internalized theoretical presuppositions about how the social and behavioral worlds operate. And although such presuppositions are essential in making…

  13. Theoretical Considerations for Project Costs.

    ERIC Educational Resources Information Center

    Johnson, Charles E.; Johnson, Cecil G.

    This bulletin is a reprint of Part 3 of the College of Education, University of Georgia's proposal to the U.S. Department of Health, Education and Welfare, Office of Education (USOE) to undertake a feasibility study of the Georgia educational model (Johnson, 1969). It is a discussion of the theoretical considerations underlying procedures which…

  14. Data, Methods, and Theoretical Implications

    ERIC Educational Resources Information Center

    Hannagan, Rebecca J.; Schneider, Monica C.; Greenlee, Jill S.

    2012-01-01

    Within the subfields of political psychology and the study of gender, the introduction of new data collection efforts, methodologies, and theoretical approaches are transforming our understandings of these two fields and the places at which they intersect. In this article we present an overview of the research that was presented at a National…

  15. Theoretical understanding of chromospheric inhomogeneities

    NASA Technical Reports Server (NTRS)

    Delache, P.

    1973-01-01

    Detailed theoretical studies of chromospheric inhomogeneities consider dynamics as well as radiative transfer of mass flow as a consequence of energy deposition. It is shown that pressure is exerted by the heating waves, especially in inhomogeneous structures, where they can be defracted. A dynamical model is formulated that depicts the inhomogeneous structure of the chromosphere-corona transition region through mass flow regimes.

  16. Theoretical predictions for exotic hadrons

    SciTech Connect

    Barnes, T. |

    1996-12-31

    In this contribution the authors discuss current theoretical expectations for the properties of light meson exotica, which are meson resonances outside the q{anti q} quark model. Specifically they discuss expectations for gluonic hadrons (glueballs and hybrids) and multiquark systems (molecules). Experimental candidates for these states are summarized, and the relevance of a TCF to these studies is stressed.

  17. Theoretical problems of spiral galaxies

    NASA Technical Reports Server (NTRS)

    Yuan, C.

    1982-01-01

    Three theoretical problems concerning the large scale structure of disk galaxies in general, and the Milky Way System, in particular, were proposed to study. They are, namely, modes of spiral density waves, evolutionary change of the abundance distribution of the gas in the Milky Way System and the motions of the cloud medium behind the large scale galactic shock.

  18. Space Service Market (Theoretical Aspect)

    NASA Astrophysics Data System (ADS)

    Prisniakov, V. F.; Prisniakova, L. M.

    The authors propose a mathematical model of the demand and supply in the market economics and in the market of space services, in particular. A theoretical demand formula and a real curve demand are compared. The market equilibrium price is defined. The space market dynamics is studied. The calculations are carried out for the parameters which are close to the market of space services.

  19. Lightning Talks 2015: Theoretical Division

    SciTech Connect

    Shlachter, Jack S.

    2015-11-25

    This document is a compilation of slides from a number of student presentations given to LANL Theoretical Division members. The subjects cover the range of activities of the Division, including plasma physics, environmental issues, materials research, bacterial resistance to antibiotics, and computational methods.

  20. Neutron Characterization for Additive Manufacturing

    NASA Technical Reports Server (NTRS)

    Watkins, Thomas; Bilheux, Hassina; An, Ke; Payzant, Andrew; DeHoff, Ryan; Duty, Chad; Peter, William; Blue, Craig; Brice, Craig A.

    2013-01-01

    Oak Ridge National Laboratory (ORNL) is leveraging decades of experience in neutron characterization of advanced materials together with resources such as the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) shown in Fig. 1 to solve challenging problems in additive manufacturing (AM). Additive manufacturing, or three-dimensional (3-D) printing, is a rapidly maturing technology wherein components are built by selectively adding feedstock material at locations specified by a computer model. The majority of these technologies use thermally driven phase change mechanisms to convert the feedstock into functioning material. As the molten material cools and solidifies, the component is subjected to significant thermal gradients, generating significant internal stresses throughout the part (Fig. 2). As layers are added, inherent residual stresses cause warping and distortions that lead to geometrical differences between the final part and the original computer generated design. This effect also limits geometries that can be fabricated using AM, such as thin-walled, high-aspect- ratio, and overhanging structures. Distortion may be minimized by intelligent toolpath planning or strategic placement of support structures, but these approaches are not well understood and often "Edisonian" in nature. Residual stresses can also impact component performance during operation. For example, in a thermally cycled environment such as a high-pressure turbine engine, residual stresses can cause components to distort unpredictably. Different thermal treatments on as-fabricated AM components have been used to minimize residual stress, but components still retain a nonhomogeneous stress state and/or demonstrate a relaxation-derived geometric distortion. Industry, federal laboratory, and university collaboration is needed to address these challenges and enable the U.S. to compete in the global market. Work is currently being conducted on AM technologies at the ORNL

  1. Communication, Work Systems and HRD

    ERIC Educational Resources Information Center

    Pace, R. Wayne

    2013-01-01

    Purpose: The purpose of this article is to show the foundational place that communication theory and its practice occupies in functioning work systems. Design/methodology/approach: This paper defines the word communication in terms of the creation and interpretation of displays, describes what it means to have a theoretical foundation for a…

  2. Subjectivity, Lifeworld, and Work Organization

    ERIC Educational Resources Information Center

    Leithaeuser, Thomas

    2010-01-01

    The bases of the article are the results of an empirical study about traditional work places in industry. There were made group discussions and special qualitative interviews with workers and employees of a German factory. The article tries to interpret and to integrate these subjective concepts in the actual discussion of theoretical perspectives…

  3. Children's Working Theories: Invoking Disequilibrium

    ERIC Educational Resources Information Center

    Lovatt, Daniel; Hedges, Helen

    2015-01-01

    One of the outcomes of the New Zealand early childhood curriculum, "Te Whariki", is "working theories". Prior research on this concept has primarily utilised sociocultural theoretical underpinnings and neglected Piagetian constructivist theories. This paper explores ways the Piagetian concepts of equilibrium and disequilibrium…

  4. Working Together

    ERIC Educational Resources Information Center

    Sullivan, Margaret

    2010-01-01

    Students need space to gather, share ideas, talk, develop common understanding and work to create greater knowledge. This focus on collaboration has put a strain on group study spaces. Students need to collaborate spontaneously, and scheduling time in a study room is not conducive to spur-of-the-moment collaboration. At many education…

  5. Working Information

    ERIC Educational Resources Information Center

    Lloyd, Annemaree; Somerville, Margaret

    2006-01-01

    Purpose: The purpose of this article is to explore the contribution that an information literacy approach to the empirical study of workplace learning can make to how people understand and conceptualise workplace learning. Design/methodology/approach: Three cohorts of fire-fighters working in two regional locations in NSW, Australia were…

  6. Wetlands Work

    ERIC Educational Resources Information Center

    Messina, Linda; Blanchard, Pamela Borne

    2004-01-01

    This article describes how a biology teacher's search for a cross-curricular project in science, math, history, and environmental science, that would help her students connect what they were learning in the classroom to their everyday life, resulted in an ongoing stewardship project. Working together with the Louisiana Sea Grant College Program…

  7. Biotechnology Works!

    ERIC Educational Resources Information Center

    Cohen, Libby G.; Spenciner, Loraine

    There have been few initiatives addressing the improvement of science education for students with disabilities. Funded by the National Science Foundation, Biotechnology Works is a summer institute in immunology and genetics for students with disabilities, high school science teachers, and high school counselors. During the 1998 summer session,…

  8. Polyelectrolyte decomplexation via addition of salt: charge correlation driven zipper.

    PubMed

    Antila, Hanne S; Sammalkorpi, Maria

    2014-03-20

    We report the first atomic scale studies of polyelectrolyte decomplexation. The complex between DNA and polylysine is shown to destabilize and spontaneously open in a gradual, reversible zipper-like mechanism driven by an increase in solution salt concentration. Divalent CaCl2 is significantly more effective than monovalent NaCl in destabilizing the complex due to charge correlations and water binding capability. The dissociation occurs accompanied by charge reversal in which charge correlations and ion binding chemistry play a key role. Our results are in agreement with experimental work on complex dissociation but in addition show the underlying microstructural correlations driving the behavior. Comparison of our full atomic level detail and dynamics results with theoretical works describing the PEs as charged, rigid rods reveals that although charge correlation involved theories provide qualitatively similar responses, considering also specific molecular chemistry and molecular level water contributions provides a more complete understanding of PE complex stability and dynamics. The findings may facilitate controlled release in gene delivery and more in general tuning of PE membrane permeability and mechanical characteristics through ionic strength.

  9. Laboratory Practical Work as a Technological Process.

    ERIC Educational Resources Information Center

    Pich-Otero, Augusto; Molina-Ortiz, Sara; Delaplace, Laura; Castellani, Oscar; Hozbor, Daniela; Sorgentini, Delia; Lodeiro, Anibal

    1998-01-01

    Evaluates the traditional method of intercalating theoretical and seminar classes with laboratory practical work. Proposes a new schedule where students get problem-based learning of theoretical concepts during the first half of the course, and plan and execute a laboratory project during the second half. (Author/CCM)

  10. Changing work systems.

    PubMed

    Clegg, C; Axtell, C; Older, M; Waterson, P

    1997-12-01

    This paper is concerned with finding practical ways of incorporating human and organizational concerns during the development and use of new information technologies (IT). It is structured in four parts. First, we outline the work of the Institute of Work Psychology at the University of Sheffield. One major interest is with the human and organizational aspects of the new information technologies. We are especially interested in work organization and job design, the allocation of tasks between and among humans and computers, the roles of users, the roles of senior managers, the management of change, and the performance of new investments in information technology (IT). Second, we review the evidence from survey work and from detailed case studies concerning the performance of IT. This reveals that most IT investments do not meet their performance objectives, and that the reasons for this are rarely purely technical in origin. Change is too often technology-led, and too little attention is paid to human and organizational factors. Most companies fail to consider how work should be organized and how jobs should be designed to make the new technologies more effective. Usually, users have no substantial influence on system development. Senior managers are criticized for their lack of understanding and action in these areas. Third, we consider the potential in the United Kingdom for changing work systems incorporating new technology. One way forward is through the development and use of sets of theoretically derived tools that can be used by managers and others. To this end we are working with several collaborators on a portfolio of tools in the following areas: organizational design job design allocation of tasks between and among humans and computers. We then review our approach and offer views of the areas and ways in which this work could develop, including opportunities for international collaboration.

  11. A Field-Theoretic Approach to the Wiener Sausage

    NASA Astrophysics Data System (ADS)

    Nekovar, S.; Pruessner, G.

    2016-05-01

    The Wiener Sausage, the volume traced out by a sphere attached to a Brownian particle, is a classical problem in statistics and mathematical physics. Initially motivated by a range of field-theoretic, technical questions, we present a single loop renormalised perturbation theory of a stochastic process closely related to the Wiener Sausage, which, however, proves to be exact for the exponents and some amplitudes. The field-theoretic approach is particularly elegant and very enjoyable to see at work on such a classic problem. While we recover a number of known, classical results, the field-theoretic techniques deployed provide a particularly versatile framework, which allows easy calculation with different boundary conditions even of higher momenta and more complicated correlation functions. At the same time, we provide a highly instructive, non-trivial example for some of the technical particularities of the field-theoretic description of stochastic processes, such as excluded volume, lack of translational invariance and immobile particles. The aim of the present work is not to improve upon the well-established results for the Wiener Sausage, but to provide a field-theoretic approach to it, in order to gain a better understanding of the field-theoretic obstacles to overcome.

  12. Additional modes in a waveguide system of zero-index-metamaterials with defects.

    PubMed

    Fu, Yangyang; Xu, Yadong; Chen, Huanyang

    2014-09-19

    Zero-index-metamaterials (ZIM) have drawn much attention due to their intriguing properties and novel applications. Particularly, in a parallel plated ZIM waveguide system with defects, total reflection or transmission of wave can be achieved by adjusting the properties of defects. This effect has been explored extensively in different types of ZIM (e.g., epsilon-near-zero metamaterials, matched impedance ZIM, or anisotropic ZIM). Almost all previous literatures showed that only monopole modes are excited inside the defects if they are in circular cylinder shapes. However, the underlying physics for excited modes inside defects is wrongly ignored. In this work, we uncover that additional modes could be excited by theoretical analysis, which is important as it will correct the current common perception. For the case of matched impedance zero-index metamaterials (MIZIM), the additional dipole modes can be excited inside the defects when total transmission occurs. Moreover, we also observe the same results in Dirac-cone-like photonic crystals which have been demonstrated theoretically and experimentally to function as MIZIM. For another case of epsilon-near-zero metamaterials (ENZ), we find that additional higher order modes (e.g., tri-pole) can be excited inside the defects when total transmission happens. Numerical simulations are performed to verify our finding regarding the additional modes.

  13. Uncertainty in the multielemental quantification by total-reflection X-ray fluorescence: theoretical and empirical approximation.

    PubMed

    Fernández-Ruiz, R

    2008-11-15

    Nowadays, the subject of the quality assurance of the analytical results is acquiring more and more importance. This work presents a basic theoretical and empirical approximation to the expanded uncertainty associated to the TXRF measurements. Two theoretical models has been proposed and compared systematically with the empirical expanded uncertainty obtained. The main consequences derived of this work are the following; theoretical model B explains with a high degree of agreement the empirical expanded uncertainties associated to the TXRF measurements, while theoretical model A explains partially the instrumental repeatability of the TXRF system. On the other hand, an unexpected U-behavior has been found for the empirical uncertainty in TXRF measurements whose explanation can be due to the sum of several sources of uncertainty not considered like variations of the Compton background or the nonlinearity of the Si(Li) detector quantum efficiency. Additionally, it has been shown that the roughness and small geometrical variations of the sample depositions are the more important uncertainty sources in the experimental TXRF measurements.

  14. Theoretical issues in Spheromak research

    SciTech Connect

    Cohen, R. H.; Hooper, E. B.; LoDestro, L. L.; Mattor, N.; Pearlstein, L. D.; Ryutov, D. D.

    1997-04-01

    This report summarizes the state of theoretical knowledge of several physics issues important to the spheromak. It was prepared as part of the preparation for the Sustained Spheromak Physics Experiment (SSPX), which addresses these goals: energy confinement and the physics which determines it; the physics of transition from a short-pulsed experiment, in which the equilibrium and stability are determined by a conducting wall (``flux conserver``) to one in which the equilibrium is supported by external coils. Physics is examined in this report in four important areas. The status of present theoretical understanding is reviewed, physics which needs to be addressed more fully is identified, and tools which are available or require more development are described. Specifically, the topics include: MHD equilibrium and design, review of MHD stability, spheromak dynamo, and edge plasma in spheromaks.

  15. Theoretical Problems in Materials Science

    NASA Technical Reports Server (NTRS)

    Langer, J. S.; Glicksman, M. E.

    1985-01-01

    Interactions between theoretical physics and material sciences to identify problems of common interest in which some of the powerful theoretical approaches developed for other branches of physics may be applied to problems in materials science are presented. A unique structure was identified in rapidly quenched Al-14% Mn. The material has long-range directed bonds with icosahedral symmetry which does not form a regular structure but instead forms an amorphous-like quasiperiodic structure. Finite volume fractions of second phase material is advanced and is coupled with nucleation theory to describe the formation and structure of precipitating phases in alloys. Application of the theory of pattern formation to the problem of dendrite formation is studied.

  16. Mathematical Working Spaces through Networking Lens

    ERIC Educational Resources Information Center

    Artigue, Michèle

    2016-01-01

    This issue of "ZDM" collects research works sharing a common reference to the theoretical framework of Mathematical Working Spaces (MWS), a construction which emerged about one decade ago, and has progressively found its way in the mathematics education community, thanks to the collaborative work of an international group of researchers.…

  17. Theoretical value of psychological testing.

    PubMed

    Shapiro, David

    2012-01-01

    Apart from their diagnostic value, psychological tests, especially the Rorschach test, have an important theoretical value for understanding psychopathology. They present a picture of a living person, in contrast to a picture of forces and agencies within the person. This rests on 2 advantages of tests over the usual psychiatric and psychoanalytic interviews: Tests are ahistorical and they present information primarily of a formal kind.

  18. Theoretical Models of Spintronic Materials

    NASA Astrophysics Data System (ADS)

    Damewood, Liam James

    In the past three decades, spintronic devices have played an important technological role. Half-metallic alloys have drawn much attention due to their special properties and promised spintronic applications. This dissertation describes some theoretical techniques used in first-principal calculations of alloys that may be useful for spintronic device applications with an emphasis on half-metallic ferromagnets. I consider three types of simple spintronic materials using a wide range of theoretical techniques. They are (a) transition metal based half-Heusler alloys, like CrMnSb, where the ordering of the two transition metal elements within the unit cell can cause the material to be ferromagnetic semiconductors or semiconductors with zero net magnetic moment, (b) half-Heusler alloys involving Li, like LiMnSi, where the Li stabilizes the structure and increases the magnetic moment of zinc blende half-metals by one Bohr magneton per formula unit, and (c) zinc blende alloys, like CrAs, where many-body techniques improve the fundamental gap by considering the physical effects of the local field. Also, I provide a survey of the theoretical models and numerical methods used to treat the above systems.

  19. Tough, High-Performance, Thermoplastic Addition Polymers

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H.; Proctor, K. Mason; Gleason, John; Morgan, Cassandra; Partos, Richard

    1991-01-01

    Series of addition-type thermoplastics (ATT's) exhibit useful properties. Because of their addition curing and linear structure, ATT polymers have toughness, like thermoplastics, and easily processed, like thermosets. Work undertaken to develop chemical reaction forming stable aromatic rings in backbone of ATT polymer, combining high-temperature performance and thermo-oxidative stability with toughness and easy processibility, and minimizing or eliminating necessity for tradeoffs among properties often observed in conventional polymer syntheses.

  20. Exploring occupational and behavioral risk factors for obesity in firefighters: a theoretical framework and study design.

    PubMed

    Choi, Bongkyoo; Schnall, Peter; Dobson, Marnie; Israel, Leslie; Landsbergis, Paul; Galassetti, Pietro; Pontello, Andria; Kojaku, Stacey; Baker, Dean

    2011-12-01

    Firefighters and police officers have the third highest prevalence of obesity among 41 male occupational groups in the United States (US). However, few studies have examined the relationship of firefighter working conditions and health behaviors with obesity. This paper presents a theoretical framework describing the relationship between working conditions, health behaviors, and obesity in firefighters. In addition, the paper describes a detailed study plan for exploring the role of occupational and behavioral risk factors in the development of obesity in firefighters enrolled in the Orange County Fire Authority Wellness Fitness Program. The study plan will be described with emphasis on its methodological merits: adopting a participatory action research approach, developing a firefighter-specific work and health questionnaire, conducting both a cross-sectional epidemiological study using the questionnaire and a sub-study to assess the validity of the questionnaire with dietary intake and physical activity measures, and evaluating the strengths and weaknesses of the body mass index as an obesity measure in comparison to skinfold-based percent body fat. The study plan based on a theoretical framework can be an essential first step for establishing effective intervention programs for obesity among professional and voluntary firefighters.

  1. Working Electrodes

    NASA Astrophysics Data System (ADS)

    Komorsky-Lovrić, Šebojka

    In electrochemistry an electrode is an electronic conductor in contact with an ionic conductor. The electronic conductor can be a metal, or a semiconductor, or a mixed electronic and ionic conductor. The ionic conductor is usually an electrolyte solution; however, solid electrolytes and ionic melts can be used as well. The term "electrode" is also used in a technical sense, meaning the electronic conductor only. If not specified otherwise, this meaning of the term "electrode" is the subject of the present chapter. In the simplest case the electrode is a metallic conductor immersed in an electrolyte solution. At the surface of the electrode, dissolved electroactive ions change their charges by exchanging one or more electrons with the conductor. In this electrochemical reaction both the reduced and oxidized ions remain in solution, while the conductor is chemically inert and serves only as a source and sink of electrons. The technical term "electrode" usually also includes all mechanical parts supporting the conductor (e.g., a rotating disk electrode or a static mercury drop electrode). Furthermore, it includes all chemical and physical modifications of the conductor, or its surface (e.g., a mercury film electrode, an enzyme electrode, and a carbon paste electrode). However, this term does not cover the electrolyte solution and the ionic part of a double layer at the electrode/solution interface. Ion-selective electrodes, which are used in potentiometry, will not be considered in this chapter. Theoretical and practical aspects of electrodes are covered in various books and reviews [1-9].

  2. Theoretical studies of condensed-phase chemistry

    NASA Astrophysics Data System (ADS)

    Johnson, Michael Andrew

    1999-12-01

    The material presented here can be divided into two categories, (i)chemistry of energetic materials, or (ii)interfacial quantum chemistry. The work in Chapters 2 and 3 was performed as part of a program to simulate accidental fires and explosions. Combustion simulations rely on a great deal of chemical information such as enthalpy changes and reaction barriers for hundreds of chemical reactions, and Chapter 2 proposes a strategy for efficient calculation of these parameters. Also important in the simulation of combustion is the ability to track physical properties through phase changes. Chapter 3 emphasizes the importance of polarization in the crystal phase of DMNA; this knowledge is vital to the development of accurate molecular dynamics force fields for simulating thermophysical properties of explosive materials. Chapters 4, 5, and 6, are devoted to forefront theoretical research in the field of interfacial chemistry. As an example of chemistry at the solid-vacuum interface, the catalytic production of methyl radicals over lithium-doped magnesium oxide is considered. A new mechanism is proposed for the catalytic coupling of methane that is more consistent with available experimental data than the previously proposed Ito- Lunsford mechanism. The final two chapters describe in great detail the interactions of water with the magnesium oxide (100) surface. Applied is a novel theoretical approach that combines an embedded quantum cluster for modeling the crystal surface with a dielectric continuum representation of the solution phase. Validation of this approach is achieved by demonstrating that it can reasonably model complicated many-body interactions at solid-liquid interfaces. Attention is then focused on the challenging problem regarding the chemical reactivity of the MgO-water interface. Presented are both experimental and theoretical studies that provide new evidence for dissociative chemisorption of water molecules at the MgO(100) interface with bulk water

  3. A theoretical framework for negotiating the path of emergency management multi-agency coordination.

    PubMed

    Curnin, Steven; Owen, Christine; Paton, Douglas; Brooks, Benjamin

    2015-03-01

    Multi-agency coordination represents a significant challenge in emergency management. The need for liaison officers working in strategic level emergency operations centres to play organizational boundary spanning roles within multi-agency coordination arrangements that are enacted in complex and dynamic emergency response scenarios creates significant research and practical challenges. The aim of the paper is to address a gap in the literature regarding the concept of multi-agency coordination from a human-environment interaction perspective. We present a theoretical framework for facilitating multi-agency coordination in emergency management that is grounded in human factors and ergonomics using the methodology of core-task analysis. As a result we believe the framework will enable liaison officers to cope more efficiently within the work domain. In addition, we provide suggestions for extending the theory of core-task analysis to an alternate high reliability environment.

  4. THEORETICAL STUDIES OF NUCLEATION KINETICS AND NANODROPLET MICROSTRUCTURE

    SciTech Connect

    Wilemski, Gerald

    2009-01-31

    The goals of this project were to (1) explore ways of bridging the gap between fundamental molecular nucleation theories and phenomenological approaches based on thermodynamic reasoning, (2) test and improve binary nucleation theory, and (3) provide the theoretical underpinning for a powerful new experimental technique, small angle neutron scattering (SANS) from nanodroplet aerosols, that can probe the compositional structure of nanodroplets. This report summarizes the accomplishments of this project in realizing these goals. Publications supported by this project fall into three general categories: (1) theoretical work on nucleation theory (2) experiments and modeling of nucleation and condensation in supersonic nozzles, and (3) experimental and theoretical work on nanodroplet structure and neutron scattering. These publications are listed and briefly summarized in this report.

  5. Priming addition facts with semantic relations.

    PubMed

    Bassok, Miriam; Pedigo, Samuel F; Oskarsson, An T

    2008-03-01

    Results from 2 relational-priming experiments suggest the existence of an automatic analogical coordination between semantic and arithmetic relations. Word pairs denoting object sets served as primes in a task that elicits "obligatory" activation of addition facts (5 + 3 activates 8; J. LeFevre, J. Bisanz, & L. Mrkonjic, 1988). Semantic relations between the priming words were either aligned or misaligned with the structure of addition (M. Bassok, V. M. Chase, & S. A. Martin, 1998). Obligatory activation of addition facts occurred when the digits were primed by categorically related words (tulips-daisies), which are aligned with addition, but did not occur when the digits were primed by unrelated words (hens-radios, Experiment 1) or by functionally related words (records-songs, Experiment 2), which are misaligned with addition. These findings lend support to the viability of automatic analogical priming (B. A. Spellman, K. J. Holyoak, & R. G. Morrison, 2001) and highlight the relevance of arithmetic applications to theoretical accounts of mental arithmetic. PMID:18315410

  6. Theoretical Sum Frequency Generation Spectroscopy of Peptides

    PubMed Central

    2015-01-01

    Vibrational sum frequency generation (SFG) has become a very promising technique for the study of proteins at interfaces, and it has been applied to important systems such as anti-microbial peptides, ion channel proteins, and human islet amyloid polypeptide. Moreover, so-called “chiral” SFG techniques, which rely on polarization combinations that generate strong signals primarily for chiral molecules, have proven to be particularly discriminatory of protein secondary structure. In this work, we present a theoretical strategy for calculating protein amide I SFG spectra by combining line-shape theory with molecular dynamics simulations. We then apply this method to three model peptides, demonstrating the existence of a significant chiral SFG signal for peptides with chiral centers, and providing a framework for interpreting the results on the basis of the dependence of the SFG signal on the peptide orientation. We also examine the importance of dynamical and coupling effects. Finally, we suggest a simple method for determining a chromophore’s orientation relative to the surface using ratios of experimental heterodyne-detected signals with different polarizations, and test this method using theoretical spectra. PMID:25203677

  7. A theoretical model of water and trade

    NASA Astrophysics Data System (ADS)

    Dang, Qian; Konar, Megan; Reimer, Jeffrey J.; Di Baldassarre, Giuliano; Lin, Xiaowen; Zeng, Ruijie

    2016-03-01

    Water is an essential input for agricultural production. Agriculture, in turn, is globalized through the trade of agricultural commodities. In this paper, we develop a theoretical model that emphasizes four tradeoffs involving water-use decision-making that are important yet not always considered in a consistent framework. One tradeoff focuses on competition for water among different economic sectors. A second tradeoff examines the possibility that certain types of agricultural investments can offset water use. A third tradeoff explores the possibility that the rest of the world can be a source of supply or demand for a country's water-using commodities. The fourth tradeoff concerns how variability in water supplies influences farmer decision-making. We show conditions under which trade liberalization affect water use. Two policy scenarios to reduce water use are evaluated. First, we derive a target tax that reduces water use without offsetting the gains from trade liberalization, although important tradeoffs exist between economic performance and resource use. Second, we show how subsidization of water-saving technologies can allow producers to use less water without reducing agricultural production, making such subsidization an indirect means of influencing water use decision-making. Finally, we outline conditions under which riskiness of water availability affects water use. These theoretical model results generate hypotheses that can be tested empirically in future work.

  8. Investigation of a theoretical magnetic refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Snead, Joshua D.

    This research paper studies the concept of developing a different type of freezer rather than vapor-compression for Dippin' Dots, a company who sells frozen goods. The freezer in question is a magnetic freezer that works by removing the compressor and bringing in magnetocaloric materials, which provide cooling by being subjected to a magnetic field. Many possibilities for improvements are available from this technology including a safer more environmentally benign fluid, a higher efficiency, and a possible cost savings. A theoretical model was designed and efficiency calculations and a cost analysis were both performed to determine if there were any improvements and if constructing a prototype freezer was feasible. The coefficient of performance of the designed freezer had the theoretical capability of being up to 5 times that of the vapor-compression freezer, but with the pumps found to complete the design this high number fell significantly short. The price to build a prototype was calculated to be around $7,050. After considering the data building a magnetic freezer prototype does not seem feasible. Although this freezer does not seem reasonable, the magnetic refrigerator technology seems applicable for other uses and is capable of developing in the future.

  9. A Theoretical Model of Water and Trade

    NASA Astrophysics Data System (ADS)

    Dang, Q.; Konar, M.; Reimer, J.; Di Baldassarre, G.; Lin, X.; Zeng, R.

    2015-12-01

    Water is an essential factor of agricultural production. Agriculture, in turn, is globalized through the trade of food commodities. In this paper, we develop a theoretical model of a small open economy that explicitly incorporates water resources. The model emphasizes three tradeoffs involving water decision-making that are important yet not always considered within the existing literature. One tradeoff focuses on competition for water among different sectors when there is a shock to one of the sectors only, such as trade liberalization and consequent higher demand for the product. A second tradeoff concerns the possibility that there may or may not be substitutes for water, such as increased use of sophisticated irrigation technology as a means to increase crop output in the absence of higher water availability. A third tradeoff explores the possibility that the rest of the world can be a source of supply or demand for a country's water-using products. A number of propositions are proven. For example, while trade liberalization tends to increase water use, increased pressure on water supplies can be moderated by way of a tax that is derivable with observable economic phenomena. Another example is that increased riskiness of water availability tends to cause water users to use less water than would be the case under profit maximization. These theoretical model results generate hypotheses that can be tested empirically in future work.

  10. Improper ferroelectricity: A theoretical and experimental investigation

    NASA Astrophysics Data System (ADS)

    Hardy, J. R.; Ullman, F. G.

    1984-02-01

    A combined theoretical and experimental study has been made of the origins and properties of the improper ferroelectricity associated with structural modulations of non-zero wavelengths. Two classes of materials have been studied: rare earth molybdates (specifically, gadolinium molybdate: GMO), and potassium selenate and its isomorphs. In the former, the modulation is produced by a zone boundary phonon instability, and in the latter by the instability of a phonon of wave vector approximately two-thirds of the way to the zone-boundary. In the second case the initial result is a modulated structure whose repeat distance is not a rational multiple of the basic lattice repeat distance. This result is a modulated polarization which, when the basic modulation locks in to a rational multiple of the lattice spacing, becomes uniform, and improper ferroelectricity results. The origins of these effects have been elucidated by theoretical studies, initially semi-empirical, but subsequently from first-principles. These complemented the experimental work, which primarily used inelastic light scattering, uniaxial stress, and hydrostatic pressure, to probe the balance between the interionic forces through the effects on the phonons and dielectric properties.

  11. Theoretical studies of hadrons and nuclei

    SciTech Connect

    COTANCH, STEPHEN R

    2007-03-20

    This report details final research results obtained during the 9 year period from June 1, 1997 through July 15, 2006. The research project, entitled Theoretical Studies of Hadrons and Nuclei , was supported by grant DE-FG02-97ER41048 between North Carolina State University [NCSU] and the U. S. Department of Energy [DOE]. In compliance with grant requirements the Principal Investigator [PI], Professor Stephen R. Cotanch, conducted a theoretical research program investigating hadrons and nuclei and devoted to this program 50% of his time during the academic year and 100% of his time in the summer. Highlights of new, significant research results are briefly summarized in the following three sections corresponding to the respective sub-programs of this project (hadron structure, probing hadrons and hadron systems electromagnetically, and many-body studies). Recent progress is also discussed in a recent renewal/supplemental grant proposal submitted to DOE. Finally, full detailed descriptions of completed work can be found in the publications listed at the end of this report.

  12. Additive Transforms Paint into Insulation

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Tech Traders Inc. sought assistance developing low-cost, highly effective coatings and paints that created useful thermal reflectance and were safe and non-toxic. In cooperation with a group of engineers at Kennedy Space Center., Tech Traders created Insuladd, a powder additive made up of microscopic, inert gas-filled, ceramic microspheres that can be mixed into ordinary interior or exterior paint, allowing the paint to act like a layer of insulation. When the paint dries, this forms a radiant heat barrier, turning the ordinary house paint into heat-reflecting thermal paint. According to Tech Traders, the product works with all types of paints and coatings and will not change the coverage rate, application, or adhesion of the paint. Other useful applications include feed storage silos to help prevent feed spoilage, poultry hatcheries to reduce the summer heat and winter cold effects, and on military vehicles and ships. Tech Traders has continued its connection to the aerospace community by recently providing Lockheed Martin Corporation with one of its thermal products for use on the F-22 Raptor.

  13. The "working" of working memory.

    PubMed

    Miller, Earl K

    2013-12-01

    This review examines the evidence for a neurobiological explanation of executive functions of working memory. We suggest that executive control stems from information about task rules acquired by mixed selective, adaptive coding, multifunctional neurons in the prefrontal cortex. The output of these neurons dynamically links the cortex-wide networks needed to complete the task. The linking may occur via synchronizing of neural rhythms, which may explain why we have a limited capacity for simultaneous thought.

  14. A theoretical framework for jamming in confluent biological tissues

    NASA Astrophysics Data System (ADS)

    Manning, M. Lisa

    2015-03-01

    For important biological functions such as wound healing, embryonic development, and cancer tumorogenesis, cells must initially rearrange and move over relatively large distances, like a liquid. Subsequently, these same tissues must undergo buckling and support shear stresses, like a solid. Our work suggests that biological tissues can accommodate these disparate requirements because the tissues are close to glass or jamming transition. While recent self propelled particle models generically predict a glass/jamming transition that is driven by packing density φ and happens at some critical φc less than unity, many biological tissues that are confluent with no gaps between cells appear to undergo a jamming transition at a constant density (φ = 1). I will discuss a new theoretical framework for predicting energy barriers and rates of cell migration in 2D tissue monolayers, and show that this model predicts a novel type of rigidity transition, which takes place at constant φ = 1 and depends only on single cell properties such as cell-cell adhesion, cortical tension and cell elasticity. This model additionally predicts that an experimentally observable parameter, the ratio between a cell's perimeter and the square root of its cross-sectional area, attains a specific, critical value at the jamming transition. We show that this prediction is precisely realized in primary epithelial cultures from human patients, with implications for asthma pathology.

  15. Theoretical Formalism To Estimate the Positron Scattering Cross Section.

    PubMed

    Singh, Suvam; Dutta, Sangita; Naghma, Rahla; Antony, Bobby

    2016-07-21

    A theoretical formalism is introduced in this article to calculate the total cross sections for positron scattering. This method incorporates positron-target interaction in the spherical complex optical potential formalism. The study of positron collision has been quite subtle until now. However, recently, it has emerged as an interesting area due to its role in atomic and molecular structure physics, astrophysics, and medicine. With the present method, the total cross sections for simple atoms C, N, and O and their diatomic molecules C2, N2, and O2 are obtained and compared with existing data. The total cross section obtained in the present work gives a more consistent shape and magnitude than existing theories. The characteristic dip below 10 eV is identified due to the positronium formation. The deviation of the present cross section with measurements at energies below 10 eV is attributed to the neglect of forward angle-discrimination effects in experiments, the inefficiency of additivity rule for molecules, empirical treatment of positronium formation, and the neglect of annihilation reactions. In spite of these deficiencies, the present results show consistent behavior and reasonable agreement with previous data, wherever available. Besides, this is the first computational model to report positron scattering cross sections over the energy range from 1 to 5000 eV. PMID:27333337

  16. Investigations in Experimental and Theoretical High Energy Physics

    SciTech Connect

    Krennrich, Frank

    2013-07-29

    We report on the work done under DOE grant DE-FG02-01ER41155. The experimental tasks have ongoing efforts at CERN (ATLAS), the Whipple observatory (VERITAS) and R&D work on dual readout calorimetry and neutrino-less double beta decay. The theoretical task emphasizes the weak interaction and in particular CP violation and neutrino physics. The detailed descriptions of the final report on each project are given under the appropriate task section of this report.

  17. Theoretical and material studies on thin-film electroluminescent devices

    NASA Technical Reports Server (NTRS)

    Summers, C. J.; Goldman, J. A.; Brennan, K.

    1988-01-01

    During this report period work was performed on the modeling of High Field Electronic Transport in Bulk ZnS and ZnSe, and also on the surface cleaning of Si for MBE growth. Some MBE growth runs have also been performed in the Varian GEN II System. A brief outline of the experimental work is given. A complete summary will be done at the end of the next reporting period at the completion of the investigation. The theoretical studies are included.

  18. Theoretical Evaluation Self-Test (Test): A Preliminary Validation Study

    ERIC Educational Resources Information Center

    Coleman, Daniel

    2004-01-01

    Over nearly 40 years, several scales have been developed to measure therapist theoretical orientation (Poznanski & McLennan, 1995). This study, unlike previous efforts, focuses on "community clinicians"--social workers and other mental health professionals (such as psychologists, counselors, psychiatrists, and psychiatric nurses) who work in…

  19. Comparing Theoretical Perspectives in Describing Mathematics Departments: Complexity and Activity

    ERIC Educational Resources Information Center

    Beswick, Kim; Watson, Anne; De Geest, Els

    2010-01-01

    We draw on two studies of mathematics departments in 11-18 comprehensive maintained schools in England to compare and contrast the insights provided by differing theoretical perspectives. In one study, activity theory was used to describe common features of the work of three departments. In the other, a mathematics department was viewed and…

  20. Corporate Library Impact, Part I: A Theoretical Approach

    ERIC Educational Resources Information Center

    Edgar, William

    2004-01-01

    Drawing on library and information science, strategy, and organizational theory, this article presents a theoretical approach to the determination of corporate library contribution to its parent firm. This approach departs from previous work on this topic, which focused on corporate library contribution to corporate operations and standing,…

  1. A Theoretical Framework towards Understanding of Emotional and Behavioural Difficulties

    ERIC Educational Resources Information Center

    Poulou, Maria S.

    2014-01-01

    Children's emotional and behavioural difficulties are the result of multiple individual, social and contextual factors working in concert. The current paper proposes a theoretical framework to interpret students' emotional and behavioural difficulties in schools, by taking into consideration teacher-student relationships, students'…

  2. A Sociocultural Perspective of Learning: Developing a New Theoretical Tenet

    ERIC Educational Resources Information Center

    Phan, Huy P.

    2012-01-01

    Explanation pertaining to individuals' cognitive development and learning approaches is a recurring theme in the areas of education and psychology. The work of Okagaki (e.g., Okagaki, 2001; Okagaki & Frensch, 1998), for example, has provided both theoretical and empirical insights into the structuring and situational positioning of individuals…

  3. Theoretical Notes on the Sociological Analysis of School Reform Networks

    ERIC Educational Resources Information Center

    Ladwig, James G.

    2014-01-01

    Nearly two decades ago, Ladwig outlined the theoretical and methodological implications of Bourdieu's concept of the social field for sociological analyses of educational policy and school reform. The current analysis extends this work to consider the sociological import of one of the most ubiquitous forms of educational reform found around…

  4. Theoretical modeling for the stereo mission

    NASA Astrophysics Data System (ADS)

    Aschwanden, Markus J.; Burlaga, L. F.; Kaiser, M. L.; Ng, C. K.; Reames, D. V.; Reiner, M. J.; Gombosi, T. I.; Lugaz, N.; Manchester, W.; Roussev, I. I.; Zurbuchen, T. H.; Farrugia, C. J.; Galvin, A. B.; Lee, M. A.; Linker, J. A.; Mikić, Z.; Riley, P.; Alexander, D.; Sandman, A. W.; Cook, J. W.; Howard, R. A.; Odstrčil, D.; Pizzo, V. J.; Kóta, J.; Liewer, P. C.; Luhmann, J. G.; Inhester, B.; Schwenn, R. W.; Solanki, S. K.; Vasyliunas, V. M.; Wiegelmann, T.; Blush, L.; Bochsler, P.; Cairns, I. H.; Robinson, P. A.; Bothmer, V.; Kecskemety, K.; Llebaria, A.; Maksimovic, M.; Scholer, M.; Wimmer-Schweingruber, R. F.

    2008-04-01

    We summarize the theory and modeling efforts for the STEREO mission, which will be used to interpret the data of both the remote-sensing (SECCHI, SWAVES) and in-situ instruments (IMPACT, PLASTIC). The modeling includes the coronal plasma, in both open and closed magnetic structures, and the solar wind and its expansion outwards from the Sun, which defines the heliosphere. Particular emphasis is given to modeling of dynamic phenomena associated with the initiation and propagation of coronal mass ejections (CMEs). The modeling of the CME initiation includes magnetic shearing, kink instability, filament eruption, and magnetic reconnection in the flaring lower corona. The modeling of CME propagation entails interplanetary shocks, interplanetary particle beams, solar energetic particles (SEPs), geoeffective connections, and space weather. This review describes mostly existing models of groups that have committed their work to the STEREO mission, but is by no means exhaustive or comprehensive regarding alternative theoretical approaches.

  5. Magnetic Reconnection: Theoretical and Observational Perspectives: Preface

    NASA Technical Reports Server (NTRS)

    Lewis, W. S.; Antiochos, S. K,; Drake, J. F.

    2011-01-01

    Magnetic reconnection is a fundamental plasma-physical process by which energy stored in a magnetic field is converted, often explosively, into heat and the kinetic energy of the charged particles that constitute the plasma. It occurs in a variety of astrophysical settings, ranging from the solar corona to pulsar magnetospheres and winds, as well as in laboratory fusion experiments, where it is responsible for sawtooth crashes. First proposed by R.G. Giovanelli in the late I 940s as the mechanism responsible for solar flares, magnetic reconnection was invoked at the beginning of the space age to explain not just solar flares but also the transfer of energy, mass, and momentum from the solar wind to Earth's magnetosphere and the subsequent storage and release of the transferred energy in the magnetotai\\. During the half century or so that has followed the seminal theoretical works by J.W. Dungey, P.A. Sweet, E.N. Parker, and H.E. Petschek, in-situ measurements by Earth-orbiting satellites and remote-sensing observations of the solar corona have provided a growing body of evidence for the occurrence of reconnection at the Sun, in the solar wind, and in the near-Earth space environment. The last thirty years have also seen the development of laboratory reconnection experiments at a number of institutions. In parallel with the efforts of experimentalists in both space and laboratory plasma physics, theorists have investigated, analytically and with the help of increasingly powerful MHD, hybrid, and kinetic numerical simulations, the structure of the diffusion region, the factors controlling the rate, onset, and cessation of reconnection, and the detailed physics that enables the demagnetization of the ions and electrons and the topological reconfiguration of the magnetic field. Moreover, the scope of theoretical reconnection studies has been extended well beyond solar system and laboratory plasmas to include more exotic astrophysical plasma systems whose strong (10

  6. Work function of binary alloys

    NASA Astrophysics Data System (ADS)

    Ishii, Ryusuke; Matsumura, Katsunori; Sakai, Akira; Sakata, Toyo

    2001-01-01

    By utilizing the field emission method, we have studied the composition dependence of work function in NiCu and PtRh alloys. In PtRh alloys, we find that the work function falls below the linear interpolation, in agreement with the experimental results on AgAu alloys [Fain and McDavid, Phys. Rev. B 9 (1974) 5099]. On the other hand, the work function of NiCu alloys is found to show little systematic deviation from the linear interpolation. The observed negative deviation in PtRh alloys is not compatible with a simple theoretical prediction based on the electronic density of states.

  7. Theoretical studies of combustion dynamics

    SciTech Connect

    Bowman, J.M.

    1993-12-01

    The basic objectives of this research program are to develop and apply theoretical techniques to fundamental dynamical processes of importance in gas-phase combustion. There are two major areas currently supported by this grant. One is reactive scattering of diatom-diatom systems, and the other is the dynamics of complex formation and decay based on L{sup 2} methods. In all of these studies, the authors focus on systems that are of interest experimentally, and for which potential energy surfaces based, at least in part, on ab initio calculations are available.

  8. CLIENT NARRATIVES: A THEORETICAL PERSPECTIVE

    PubMed Central

    Gale, Deborah Dysart; Mitchell, Ann M.; Garand, Linda; Wesner, Susan

    2010-01-01

    The role of subjective client narratives in health care represents a clinical and therapeutic tool, useful in complementing objective, scientific data. Of particular interest to mental health practitioners is the role narratives play as a therapeutic tool to guide clinical practice. This paper lays a foundation for understanding the importance of narrative in the psychotherapeutic process. It provides a brief overview of narrative theory and methods of structural analysis in order to provide a theoretical approach that can be utilized by nurses to address clients’ needs. PMID:12735076

  9. Some thoughts on theoretical physics

    NASA Astrophysics Data System (ADS)

    Tsallis, Constantino

    2004-12-01

    Some thoughts are presented on the inter-relation between beauty and truth in science in general and theoretical physics in particular. Some conjectural procedures that can be used to create new ideas, concepts and results are illustrated in both Boltzmann-Gibbs and nonextensive statistical mechanics. The sociological components of scientific progress and its unavoidable and benefic controversies are, mainly through existing literary texts, briefly addressed as well. Short essay based on the plenary talk given at the International Workshop on Trends and Perspectives in Extensive and Non-Extensive Statistical Mechanics, held in November 19-21, 2003, in Angra dos Reis, Brazil.

  10. Theoretical efficiency limits for thermoradiative energy conversion

    SciTech Connect

    Strandberg, Rune

    2015-02-07

    A new method to produce electricity from heat called thermoradiative energy conversion is analyzed. The method is based on sustaining a difference in the chemical potential for electron populations above and below an energy gap and let this difference drive a current through an electric circuit. The difference in chemical potential originates from an imbalance in the excitation and de-excitation of electrons across the energy gap. The method has similarities to thermophotovoltaics and conventional photovoltaics. While photovoltaic cells absorb thermal radiation from a body with higher temperature than the cell itself, thermoradiative cells are hot during operation and emit a net outflow of photons to colder surroundings. A thermoradiative cell with an energy gap of 0.25 eV at a temperature of 500 K in surroundings at 300 K is found to have a theoretical efficiency limit of 33.2%. For a high-temperature thermoradiative cell with an energy gap of 0.4 eV, a theoretical efficiency close to 50% is found while the cell produces 1000 W/m{sup 2} has a temperature of 1000 K and is placed in surroundings with a temperature of 300 K. Some aspects related to the practical implementation of the concept are discussed and some challenges are addressed. It is, for example, obvious that there is an upper boundary for the temperature under which solid state devices can work properly over time. No conclusions are drawn with regard to such practical boundaries, because the work is aimed at establishing upper limits for ideal thermoradiative devices.

  11. Additive Manufacturing: From Rapid Prototyping to Flight

    NASA Technical Reports Server (NTRS)

    Prater, Tracie

    2015-01-01

    Additive manufacturing (AM) offers tremendous promise for the rocket propulsion community. Foundational work must be performed to ensure the safe performance of AM parts. Government, industry, and academia must collaborate in the characterization, design, modeling, and process control to accelerate the certification of AM parts for human-rated flight.

  12. English as an Additional Language: Changing Perspectives.

    ERIC Educational Resources Information Center

    Leung, Constant, Ed.; Cable, Carrie, Ed.

    This volume highlights the language and learning needs of pupils with English as an additional language in the United Kingdom. It includes chapters by British teachers and researchers working in this field. The book addresses a number of issues of interest to practitioners, scholars, teacher educators, and policy makers. Each chapter is prefaced…

  13. Theoretical and experimental study of spectral characteristics of the photoacoustic signal from stochastically distributed particles.

    PubMed

    Wang, Shaohua; Tao, Chao; Yang, Yiqun; Wang, Xueding; Liu, Xiaojun

    2015-07-01

    Photoacoustic imaging is an emerging technique which inherits the merits of optical imaging and ultrasonic imaging. However, classical photoacoustic imaging mainly makes use of the time-domain parameters of signals. In contrast to previous studies, we theoretically investigate the spectral characteristics of the photoacoustic signal from stochastic distributed particles. The spectral slope is extracted and used for describing the spectral characteristics of the photoacoustic signal. Both Gaussian and spherical distributions of optical absorption in particles are considered. For both situations, the spectral slope is monotonically decreased with the increase of particle size. In addition, the quantitative relationship between the spectral slope and the imaging system factors, including the laser pulse envelope, directivity of ultrasound transducer, and signal bandwidth, are theoretically analyzed. Finally, an idealized phantom experiment is performed to validate the analyses and examine the instrument independent of the spectral slope. This work provides a theoretical framework and new experimental evidence for spectrum analysis of the photoacoustic signal. This could be helpful for quantitative tissue evaluation and imaging based on the spectral parameters of the photoacoustic signal.

  14. Quantitative Evaluation of Performance in Interventional Neuroradiology: An Integrated Curriculum Featuring Theoretical and Practical Challenges

    PubMed Central

    Ernst, Marielle; Kriston, Levente; Romero, Javier M.; Frölich, Andreas M.; Jansen, Olav; Fiehler, Jens; Buhk, Jan-Hendrik

    2016-01-01

    Purpose We sought to develop a standardized curriculum capable of assessing key competencies in Interventional Neuroradiology by the use of models and simulators in an objective, quantitative, and efficient way. In this evaluation we analyzed the associations between the practical experience, theoretical knowledge, and the skills lab performance of interventionalists. Materials and Methods We evaluated the endovascular skills of 26 participants of the Advanced Course in Endovascular Interventional Neuroradiology of the European Society of Neuroradiology with a set of three tasks (aneurysm coiling and thrombectomy in a virtual simulator and placement of an intra-aneurysmal flow disruptor in a flow model). Practical experience was assessed by a survey. Participants completed a written and oral examination to evaluate theoretical knowledge. Bivariate and multivariate analyses were performed. Results In multivariate analysis knowledge of materials and techniques in Interventional Neuroradiology was moderately associated with skills in aneurysm coiling and thrombectomy. Experience in mechanical thrombectomy was moderately associated with thrombectomy skills, while age was negatively associated with thrombectomy skills. We found no significant association between age, sex, or work experience and skills in aneurysm coiling. Conclusion Our study gives an example of how an integrated curriculum for reasonable and cost-effective assessment of key competences of an interventional neuroradiologist could look. In addition to traditional assessment of theoretical knowledge practical skills are measured by the use of endovascular simulators yielding objective, quantitative, and constructive data for the evaluation of the current performance status of participants as well as the evolution of their technical competency over time. PMID:26848840

  15. PREFACE: 12th Conference on ''Theoretical Nuclear Physics in Italy''

    NASA Astrophysics Data System (ADS)

    Bombaci, I.; Covello, A.; Marcucci, L. E.; Rosati, S.

    2009-07-01

    These Proceedings contain the invited and contributed papers presented at the 12th Conference on Theoretical Nuclear Physics in Italy held in Cortona, Italy, from 8-10 October 2008. As usual, the meeting was held at il Palazzone, a 16th century castle owned by the Scuola Normale Superiore di Pisa. The aim of this biennal conference is to bring together Italian theorists working in various fields of Nuclear Physics to discuss their latest results and confront their points of view in a lively and informal way. This offers the opportunity to promote collaborations between different groups. There were about 50 participants at the conference, coming from 14 Italian Universities (Cagliari, Catania, Ferrara, Firenze, Genova, Lecce, Milano, Napoli, Padova, Pavia, Pisa, Roma, Trento, Trieste). The program of the conference, prepared by the Organizing Committee (Ignazio Bombaci, Aldo Covello, Laura Elisa Marcucci and Sergio Rosati) focused on six main topics: Few-Nucleon Systems, Nuclear Matter and Nuclear Dynamics, Nuclear Astrophysics, Structure of Hadrons and Hadronic Matter, Nuclear Structure, Nuclear Physics with Electroweak Probes. Winfried Leidemann, Maria Colonna, Marcello Lissia, Elena Santopinto, Silvia Lenzi and Omar Benhar took the burden of giving general talks on these topics and reviewing the research activities of the various Italian groups. In addition, 19 contributed papers were presented, most of them by young participants. In the last session of the Conference there were two invited talks related to experimental activities of great current interest. Gianfranco Prete from the Laboratori Nazionali di Legnaro spoke about the Italian radioactive ion beam facility SPES and the status of the European project EURISOL, while Nicola Colonna from the INFN, Bari, gave an overview of the perspectives of development of fourth-generation nuclear reactors. We would like to thank the authors of the general reports for their hard work in reviewing the main achievements in

  16. Multiobjective information theoretic ensemble selection

    NASA Astrophysics Data System (ADS)

    Card, Stuart W.; Mohan, Chilukuri K.

    2009-05-01

    In evolutionary learning, the sine qua non is evolvability, which requires heritability of fitness and a balance between exploitation and exploration. Unfortunately, commonly used fitness measures, such as root mean squared error (RMSE), often fail to reward individuals whose presence in the population is needed to explain important data variance; and indicators of diversity generally are not only incommensurate with those of fitness but also essentially arbitrary. Thus, due to poor scaling, deception, etc., apparently relatively high fitness individuals in early generations may not contain the building blocks needed to evolve optimal solutions in later generations. To reward individuals for their potential incremental contributions to the solution of the overall problem, heritable information theoretic functionals are developed that incorporate diversity considerations into fitness, explicitly identifying building blocks suitable for recombination (e.g. for non-random mating). Algorithms for estimating these functionals from either discrete or continuous data are illustrated by application to input selection in a high dimensional industrial process control data set. Multiobjective information theoretic ensemble selection is shown to avoid some known feature selection pitfalls.

  17. Intergenerational work as an adjunct to psychoanalysis and psychotherapy.

    PubMed

    Braverman, S

    1995-01-01

    Psychotherapy and psychoanalysis are opportunities for individuals to repair faulty aspects of their development that have resulted in symptoms or other difficulties in living. Although transference is the major therapeutic tool in this work, it is not the only one. The potential resources for healing that exist in family relationships is great, especially as these relationships go on long after therapy has ended. We are all living longer; families of three and four generations are no longer uncommon. There are many adult patients who have one or both parents alive and well. Intergenerational work can be a useful adjunct where there is no severe narcissistic pathology or psychosis in either patient or parent. It is especially helpful in cases where there is severe resistance and insight is not effective in promoting change. "By focusing constantly on the patient's transference distortions and ignoring reality elements we undermine self-esteem and make him feel he is always wrong, sick or crazy" (Greenson, 1978b,p. 434). The addition of intergenerational work in the course of psychoanalysis/psychotherapy can shorten the time of therapy and be another tool for dealing with resistance. This work has theoretical implications for the modification of the place that transference has in psychoanalytic therapy. By placing greater emphasis on the patient's real relationships in influencing intrapsychic change we pave the way to exciting clinical and theoretical possibilities. PMID:8778077

  18. Regulatory focus and work-related outcomes: a review and meta-analysis.

    PubMed

    Lanaj, Klodiana; Chang, Chu-Hsiang Daisy; Johnson, Russell E

    2012-09-01

    Regulatory focus theory (Higgins, 1997) has received growing attention in organizational psychology, necessitating a quantitative review that synthesizes its effects on important criteria. In addition, there is need for theoretical integration of regulatory focus theory with personality research. Theoretical integration is particularly relevant, since personality traits and dispositions are distal factors that are unlikely to have direct effects on work behaviors, yet they may have indirect effects via regulatory focus. The current meta-analysis introduces an integrative framework in which the effects of personality on work behaviors are best understood when considered in conjunction with more proximal motivational processes such as regulatory focus. Using a distal-proximal approach, we identify personality antecedents and work-related consequences of regulatory foci in a framework that considers both general and work-specific regulatory foci as proximal motivational processes. We present meta-analytic results for relations of regulatory focus with its antecedents (approach and avoid temperaments, conscientiousness, openness to experience, agreeableness, self-esteem, and self-efficacy) and its consequences (work behaviors and attitudes). In addition to estimates of bivariate relationships, we support a meta-analytic path model in which distal personality traits relate to work behaviors via the mediating effects of general and work-specific regulatory focus. Results from tests of incremental and relative validity indicated that regulatory foci predict unique variance in work behaviors after controlling for established personality, motivation, and attitudinal predictors. Consistent with regulatory focus theory and our integrative theoretical framework, regulatory focus has meaningful relations with work outcomes and is not redundant with other individual difference variables.

  19. The influence of strategies on relationships between working memory and cognitive skills.

    PubMed

    Clair-Thompson, Helen L St

    2007-05-01

    The aim of this study was to test the effect of administration method on relationships between working memory span tasks and cognitive skills. Participants completed both participant-administered and experimenter-administered working memory measures in both verbal and visuospatial domains. Although the tasks were equally reliable, the additional time taken to implement strategies in the participant-administered tasks in the verbal domain reduced the correlations between working memory and reading comprehension and arithmetic. These findings did not extend to a visuospatial working memory measure, for which there was no significant difference between the participant-administered and experimenter-administered tasks in terms of their relationships with comprehension and arithmetic. However, performance on experimenter-administered working memory tasks in both verbal and visuospatial domains predicted unique variance in comprehension and arithmetic while controlling for scores on the participant-administered tasks. The results are discussed in terms of theoretical and practical implications for working memory research.

  20. Theoretical Determination of Lifetime of Compressed Plates at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Herrmann, George; Chu, Hu-Nan

    1959-01-01

    A method for the theoretical determination of the lifetime of com- pressed plates at elevated temperatures is presented. In this approach, linearized equations are used throughout with the assumption that the plate material is a standard linear solid. The critical time (lifetime) is determined by reducing the time-dependent behavior to the time- independent response of purely elastic buckling. Theoretically predicted lifetimes of 2024-T3 (formerly 24S-T3) aluminum-alloy plates at 450 F are compared with experimental values obtained in previous work.

  1. Critical Arterial Stenosis: A Theoretical and Experimental Solution

    PubMed Central

    Berguer, R.; Hwang, N. H. C.

    1974-01-01

    The mechanics of critical stenosis of a blood vessel are studied by means of a comprehensive theoretical model in terms of energy changes and dissipation. These theoretical assumptions correlate well with experimental data obtained in vivo. Previous work in this field is analyzed. This new treatment of the phenomenon of blood vessel stenosis allows explanation of apparent contradictions in previous studies. When the velocity of flow in the unstenosed portion and the geometry of the stenosis are known, the drop in pressure at flow can be predicted. ImagesFig. 4.Fig. 5. PMID:4835958

  2. The learning evaluation: a theoretical and empirical exploration.

    PubMed

    Edelenbos, Jurian; van Buuren, Arwin

    2005-12-01

    In this article, the authors theoretically and empirically explore the concept of learning evaluation. They shed light on the positioning of the learning evaluation amid scholarly work on evaluations. Moreover, they describe the learning evaluation in practice in the Netherlands by going into a specific project called the Stimulation Program on Citizen and Environment. The theoretical and empirical quest gives insights into the problems with and possibilities of the learning evaluation. They think that their experiences can help the further development of theory about learning evaluation as well as aid in the practice of such evaluations.

  3. Theoretical Perspectives on Sibling Relationships

    PubMed Central

    Whiteman, Shawn D.; McHale, Susan M.; Soli, Anna

    2011-01-01

    Although siblings are a fixture of family life, research on sibling relationships lags behind that on other family relationships. To stimulate interest in sibling research and to serve as a guide for future investigations by family scholars, we review four theoretical psychologically oriented perspectives—(a) psychoanalytic-evolutionary, (b) social psychological, (c) social learning, and (d) family-ecological systems—that can inform research on sibling relationships, including perspectives on the nature and influences on developmental, individual, and group differences in sibling relationships. Given that most research on siblings has focused on childhood and adolescence, our review highlights these developmental periods, but we also incorporate the limited research on adult sibling relationships, including in formulating suggestions for future research on this fundamental family relationship. PMID:21731581

  4. Theoretical Models of Astrochemical Processes

    NASA Technical Reports Server (NTRS)

    Charnley, Steven

    2009-01-01

    Interstellar chemistry provides a natural laboratory for studying exotic species and processes at densities, temperatures, and reaction rates. that are difficult or impractical to address in the laboratory. Thus, many chemical reactions considered too sloe by the standards of terrestrial chemistry, can be 'observed and modeled. Curious proposals concerning the nature and chemistry of complex interstellar organic molecules will be described. Catalytic reactions on "rain surfaces can, in principle, lead to a lame variety of species and this has motivated many laboratory and theoretical studies. Gas phase processes may also build lame species in molecular clouds. Future laboratory data and computational tools needed to construct accurate chemical models of various astronomical sources to be observed by Herschel and ALMA will be outlined.

  5. Research in Theoretical Particle Physics

    SciTech Connect

    Ralston, John P.

    2013-07-28

    This document is the final report on activity of the University of Kansas theory group supported under DOE Grant Number DE-FG02-04ER14308, ending April 30, 3013. The report covers the most recent three year period period May 1, 2010-April 30, 2013. Faculty supported by the grant during the period were Danny Marfatia (co-I), Douglas McKay (emeritus) and John Ralston (PI). The group's research topics and accomplishments covered numerous different topics subsumed under the {\\it the Energy Frontier, the Intensity Frontier}, and {\\it the Cosmic Frontier}. Many theoretical and experimental results related to the Standard Model and models of new physics were published during the reporting period. The group's research emphasis has been on challenging and confronting {\\it Anything that is Observable} about the physical Universe.

  6. Theoretical studies of molecular collisions

    NASA Technical Reports Server (NTRS)

    Kouri, Donald J.

    1991-01-01

    The following subject areas are covered: (1) total integral reactive cross sections and vibrationally resolved reaction probabilities for F + H2 = HF + H; (2) a theoretical study of inelastic O + N2 collisions; (3) body frame close coupling wave packet approach to gas phase atom-rigit rotor inelastic collisions; (4) wave packet study of gas phase atom-rigit motor scattering; (5) the application of optical potentials for reactive scattering; (6) time dependent, three dimensional body frame quantal wave packet treatment of the H + H2 exchange reaction; (7) a time dependent wave packet approach to atom-diatom reactive collision probabilities; (8) time dependent wave packet for the complete determination of s-matrix elements for reactive molecular collisions in three dimensions; (9) a comparison of three time dependent wave packet methods for calculating electron-atom elastic scattering cross sections; and (10) a numerically exact full wave packet approach to molecule-surface scattering.

  7. Incorporation of additives into polymers

    DOEpatents

    McCleskey, T. Mark; Yates, Matthew Z.

    2003-07-29

    There has been invented a method for incorporating additives into polymers comprising: (a) forming an aqueous or alcohol-based colloidal system of the polymer; (b) emulsifying the colloidal system with a compressed fluid; and (c) contacting the colloidal polymer with the additive in the presence of the compressed fluid. The colloidal polymer can be contacted with the additive by having the additive in the compressed fluid used for emulsification or by adding the additive to the colloidal system before or after emulsification with the compressed fluid. The invention process can be carried out either as a batch process or as a continuous on-line process.

  8. [Work ability: a literature review].

    PubMed

    Martinez, Maria Carmen; Latorre, Maria do Rosário Dias de Oliveira; Fischer, Frida Marina

    2010-06-01

    The aim of this article is to present a literature review on work ability and functional ageing. An extensive search of publications from 1966 to 2006 was conducted using the databases MEDLINE, LILACS and SciELO. Several aspects of work ability are presented in this manuscript: the historical context when the theme emerged, the theoretical framework, the determinant factors and an explanatory model, the current methodology to evaluate and monitor the work ability, the importance of its promotion. Highlights of the current situation about the research, practice and future perspectives regarding the theme are also discussed. In the context of the workforce aging, the work ability became an important indicator because their consequences to the worker's health, well-being and employability, with impacts to the individuals, organizations and society. In spite of their relevance, there is a lack of attention to the issues about work ability and functional ageing.

  9. [Patch-testing methods: additional specialised or additional series].

    PubMed

    Cleenewerck, M-B

    2009-01-01

    The tests in the European standard battery must occasionally be supplemented by specialised or additional batteries, particularly where the contact allergy is thought to be of occupational origin. These additional batteries cover all allergens associated with various professional activities (hairdressing, baking, dentistry, printing, etc.) and with different classes of materials and chemical products (glue, plastic, rubber...). These additional tests may also include personal items used by patients on a daily basis such as cosmetics, shoes, plants, textiles and so on.

  10. A theoretical investigation of thermodynamic effects on developed cavitation

    NASA Technical Reports Server (NTRS)

    Weir, D. S.

    1976-01-01

    The results of a theoretical investigation of thermodynamic effects on developed cavitation are presented. An approximate solution to the conservation equations for a two-phase laminar boundary layer is obtained. This analysis produces an expression for the temperature difference between the liquid and vapor phases which can be applied to developed cavity flows. Experimental data of cavity temperature depressions are correlated using this result. In addition, a theoretical estimate of the Nusselt number for the cavity is made using a turbulent boundary layer cavity model proposed by Brennen. The result agrees in part with empirically determined expressions for the cavity Nusselt number.

  11. Theoretical elementary particle research at the University of Florida

    SciTech Connect

    Field, R.D.; Ramond, P.M.; Sikivie, P.; Thorn, C.B.

    1996-12-01

    This is the annual progress report of the theoretical particle theory group at the University of Florida under DoE Grant DE-FG05-86ER40272. At present the group consists of four Full Professors (Field, Ramond, Thorn, Sikivie), two Associate Professors (Qiu, Woodard), and one Assistant Professor (Kennedy). In addition, the group has four postdoctoral research associates and three graduate students. The research of the group covers a broad range of topics in theoretical high energy physics including both theory and phenomenology. Included in this report is a summary of the last several years and an outline of the current research program.

  12. Theoretical pluralism in psychoanalytic case studies

    PubMed Central

    Willemsen, Jochem; Cornelis, Shana; Geerardyn, Filip M.; Desmet, Mattias; Meganck, Reitske; Inslegers, Ruth; Cauwe, Joachim M. B. D.

    2015-01-01

    The aim of this study is to provide an overview of the scientific activity of different psychoanalytic schools of thought in terms of the content and production of case studies published on ISI Web of Knowledge. Between March 2013 and November 2013, we contacted all case study authors included in the online archive of psychoanalytic and psychodynamic case studies (www.singlecasearchive.com) to inquire about their psychoanalytic orientation during their work with the patient. The response rate for this study was 45%. It appears that the two oldest psychoanalytic schools, Object-relations psychoanalysis and Ego psychology or “Classical psychoanalysis” dominate the literature of published case studies. However, most authors stated that they feel attached to two or more psychoanalytic schools of thought. This confirms that the theoretical pluralism in psychoanalysis stretches to the field of single case studies. The single case studies of each psychoanalytic school are described separately in terms of methodology, patient, therapist, or treatment features. We conclude that published case studies features are fairly similar across different psychoanalytic schools. The results of this study are not representative of all psychoanalytic schools, as some do not publish their work in ISI ranked journals. PMID:26483725

  13. Theoretical Characterizaiton of Visual Signatures (Muzzle Flash)

    NASA Astrophysics Data System (ADS)

    Kashinski, D. O.; Scales, A. N.; Vanderley, D. L.; Chase, G. M.; di Nallo, O. E.; Byrd, E. F. C.

    2014-05-01

    We are investigating the accuracy of theoretical models used to predict the visible, ultraviolet and infrared spectra of product materials ejected from the muzzle of currently fielded systems. Recent advances in solid propellants has made the management of muzzle signature (flash) a principle issue in weapons development across the calibers. A priori prediction of the electromagnetic spectra of formulations will allow researchers to tailor blends that yield desired signatures and determine spectrographic detection ranges. We are currently employing quantum chemistry methods at various levels of sophistication to optimize molecular geometries, compute vibrational frequencies, and determine the optical spectra of specific gas-phase molecules and radicals of interest. Electronic excitations are being computed using Time Dependent Density Functional Theory (TD-DFT). A comparison of computational results to experimental values found in the literature is used to assess the affect of basis set and functional choice on calculation accuracy. The current status of this work will be presented at the conference. Work supported by the ARL, and USMA.

  14. Neural complexity: a graph theoretic interpretation.

    PubMed

    Barnett, L; Buckley, C L; Bullock, S

    2011-04-01

    One of the central challenges facing modern neuroscience is to explain the ability of the nervous system to coherently integrate information across distinct functional modules in the absence of a central executive. To this end, Tononi et al. [Proc. Natl. Acad. Sci. USA. 91, 5033 (1994)] proposed a measure of neural complexity that purports to capture this property based on mutual information between complementary subsets of a system. Neural complexity, so defined, is one of a family of information theoretic metrics developed to measure the balance between the segregation and integration of a system's dynamics. One key question arising for such measures involves understanding how they are influenced by network topology. Sporns et al. [Cereb. Cortex 10, 127 (2000)] employed numerical models in order to determine the dependence of neural complexity on the topological features of a network. However, a complete picture has yet to be established. While De Lucia et al. [Phys. Rev. E 71, 016114 (2005)] made the first attempts at an analytical account of this relationship, their work utilized a formulation of neural complexity that, we argue, did not reflect the intuitions of the original work. In this paper we start by describing weighted connection matrices formed by applying a random continuous weight distribution to binary adjacency matrices. This allows us to derive an approximation for neural complexity in terms of the moments of the weight distribution and elementary graph motifs. In particular, we explicitly establish a dependency of neural complexity on cyclic graph motifs.

  15. Revisiting Additivity Violation of Quantum Channels

    NASA Astrophysics Data System (ADS)

    Fukuda, Motohisa

    2014-12-01

    We prove additivity violation of minimum output entropy of quantum channels by straightforward application of -net argument and Lévy's lemma. The additivity conjecture was disproved initially by Hastings. Later, a proof via asymptotic geometric analysis was presented by Aubrun, Szarek and Werner, which uses Dudley's bound on Gaussian process (or Dvoretzky's theorem with Schechtman's improvement). In this paper, we develop another proof along Dvoretzky's theorem in Milman's view, showing additivity violation in broader regimes than the existing proofs. Importantly,Dvoretzky's theorem works well with norms to give strong statements, but these techniques can be extended to functions which have norm-like structures-positive homogeneity and triangle inequality. Then, a connection between Hastings' method and ours is also discussed. In addition, we make some comments on relations between regularized minimum output entropy and classical capacity of quantum channels.

  16. Hash Functions and Information Theoretic Security

    NASA Astrophysics Data System (ADS)

    Bagheri, Nasour; Knudsen, Lars R.; Naderi, Majid; Thomsen, Søren S.

    Information theoretic security is an important security notion in cryptography as it provides a true lower bound for attack complexities. However, in practice attacks often have a higher cost than the information theoretic bound. In this paper we study the relationship between information theoretic attack costs and real costs. We show that in the information theoretic model, many well-known and commonly used hash functions such as MD5 and SHA-256 fail to be preimage resistant.

  17. Theoretical Foundations for Evidence-Based Health Informatics: Why? How?

    PubMed

    Scott, Philip J; Georgiou, Andrew; Hyppönen, Hannele; Craven, Catherine K; Rigby, Michael; Brender McNair, Jytte

    2016-01-01

    A scientific approach to health informatics requires sound theoretical foundations. Health informatics implementation would be more effective if evidence-based and guided by theories about what is likely to work in what circumstances. We report on a Medinfo 2015 workshop on this topic jointly organized by the EFMI Working Group on Assessment of Health Information Systems and the IMIA Working Group on Technology Assessment and Quality Development. We discuss the findings of the workshop and propose an approach to consolidate empirical knowledge into testable middle-range theories. PMID:27577457

  18. From "Work-Family" to "Work-Life": Broadening Our Conceptualization and Measurement

    ERIC Educational Resources Information Center

    Keeney, Jessica; Boyd, Elizabeth M.; Sinha, Ruchi; Westring, Alyssa F.; Ryan, Ann Marie

    2013-01-01

    Despite frequent reference to "work-life" issues in the organizational literature, little theoretical or empirical attention has been paid to nonwork areas beyond family. The purpose of the research described here is to move beyond work-family conflict to a broader conceptualization and measurement of work interference with life. A measure of work…

  19. Measure-theoretic sensitivity via finite partitions

    NASA Astrophysics Data System (ADS)

    Li, Jian

    2016-07-01

    For every positive integer n≥slant 2 , we introduce the concept of measure-theoretic n-sensitivity for measure-theoretic dynamical systems via finite measurable partitions, and show that an ergodic system is measure-theoretically n-sensitive but not (n  +  1)-sensitive if and only if its maximal pattern entropy is log n .

  20. Mass Media and Socialization: Theoretic Approaches.

    ERIC Educational Resources Information Center

    Gordon, Thomas F.

    This paper examines the major theoretical approaches to the study of socialization, with an emphasis on media effects. The three major bodies of literature studied are the major theoretic approaches utilized in the general area of developmental psychology, the theoretical paradigms evident in studies dealing more specifically with child…

  1. Theoretical Perspectives Guiding QOL Indicator Projects

    ERIC Educational Resources Information Center

    Sirgy, M. Joseph

    2011-01-01

    Most of the theoretically based QOL indicators projects can be classified in terms of six major theoretical concepts: (a) socio-economic development (b) personal utility, (c) just society, (d) human development, (e) sustainability, and (f) functioning. I explain the core aspects of these six theoretical paradigms and show how they help guide QOL…

  2. PREFACE: The International Conference on Theoretical Physics `Dubna-Nano2008'

    NASA Astrophysics Data System (ADS)

    Osipov, V. A.; Nesterenko, V. O.; Shukrinov, Y. M.

    2008-07-01

    The International Conference on Theoretical Physics `Dubna-Nano2008' was held on 7-11 July 2008 at the Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow region, Russia. The conference provided the opportunity for the presentation and discussion of theoretical and experimental advances in the rapidly growing area of the nanophysics, with the accent on its theoretical aspects. The multidisciplinary character of the conference allowed an effective exchange of ideas between different areas of nanophysics. The following topics were covered: carbon nanosystems (fullerenes, nanotubes, graphene), quantum dots, electron and spin transport, spectroscopy and dynamics of atomic clusters, Josephson junctions, bio-complexes, and applications of nanosystems. Approximately 90 scientists from 16 countries participated in the conference. The program included 48 oral talks and 40 posters. The 51 contributions are included in this proceedings. We would like to express our gratitude to all participants for their presentations and discussions, which made the conference so successful. We are deeply indebted to the members of the International Advisory Committee (Professors T Ando, S Datta, A V Eletskii, J Fabian, F Guinea, P Hawrylak, K Kadowaki, T Koyama, Yu I Latushev, N F Pedersen, P-G Reinhard, J M Rost, A Ya Vul') and the Local Organizing Committee for their fruitful work. The financial support of BLTP JINR, Russian Foundation for Basic Research, Heisenberg-Landau Program and Bogoliubov-Infeld Program was of a great importance. Additional information about `Dubna-Nano2008' is available at the homepage http://theor.jinr.ru/~nano08. Vladimir Osipov, Valentin Nesterenko and Yury Shukrinov Editors

  3. Mathematical challenges from theoretical/computational chemistry

    SciTech Connect

    1995-12-31

    The committee believes that this report has relevance and potentially valuable suggestions for a wide range of readers. Target audiences include: graduate departments in the mathematical and chemical sciences; federal and private agencies that fund research in the mathematical and chemical sciences; selected industrial and government research and development laboratories; developers of software and hardware for computational chemistry; and selected individual researchers. Chapter 2 of this report covers some history of computational chemistry for the nonspecialist, while Chapter 3 illustrates the fruits of some past successful cross-fertilization between mathematical scientists and computational/theoretical chemists. In Chapter 4 the committee has assembled a representative, but not exhaustive, survey of research opportunities. Most of these are descriptions of important open problems in computational/theoretical chemistry that could gain much from the efforts of innovative mathematical scientists, written so as to be accessible introductions to the nonspecialist. Chapter 5 is an assessment, necessarily subjective, of cultural differences that must be overcome if collaborative work is to be encouraged between the mathematical and the chemical communities. Finally, the report ends with a brief list of conclusions and recommendations that, if followed, could promote accelerated progress at this interface. Recognizing that bothersome language issues can inhibit prospects for collaborative research at the interface between distinctive disciplines, the committee has attempted throughout to maintain an accessible style, in part by using illustrative boxes, and has included at the end of the report a glossary of technical terms that may be familiar to only a subset of the target audiences listed above.

  4. Anaerobic sludge digestion with a biocatalytic additive

    SciTech Connect

    Ghosh, S.; Henry, M.P.; Fedde, P.A.

    1982-01-01

    The objective of this research was to evaluate the effects of a lactobacillus additive an anaerobic sludge digestion under normal, variable, and overload operating conditions. The additive was a whey fermentation product of an acid-tolerant strain of Lactobacillus acidophilus fortified with CaCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid. The lactobacillus additive is multifunctional in nature and provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. The experimental work consisted of several pairs of parallel mesophilic (35/sup 0/C) digestion runs (control and test) conducted in five experimental phases. Baseline runs without the additive showed that the two experimental digesters had the same methane content, gas production rate (GPR), and ethane yield. The effect of the additive was to increase methane yield and GPR by about 5% (which was statistically significant) during digester operation at a loading rate (LR) of 3.2 kg VS/m/sup 3/-day and a hydraulic retention time (HRT) of 14 days. Data collected from the various experimental phases showed that the biochemical additive increased methane yield, gas production rate, and VS reduction, and decreased volatile acids accumulation. In addition, it enhanced digester buffer capacity and improved the fertilizer value and dewatering characteristics of the digested residue.

  5. [Decision-making process and health management councils: theoretical approaches].

    PubMed

    Wendhausen, Agueda; Cardoso, Sandra de Mello

    2007-01-01

    With the institutionalization of participation in health, through conferences and management councils at national, state, municipal and local levels, a process of democratization is initiated in the health area. However, in relation to the health councils in particular, there is still much to be done, including improving the quality of the decision-making process. This work aims to place the decision-making process in its theoretical context in terms of participatory democracy, elements which make up, factors which influence its development, and finally, to explore some possibilities of this theoretical basis to analyze the practices of the health councils in the area of health. It is hoped that it will make a theoretical contribution to the analyses carried out in this area, in order to provide a decision-making process that is more inclusive in terms of participation.

  6. Some theoretical and algorithmic ideas in spectral line fitting problems

    NASA Astrophysics Data System (ADS)

    Ireland, J.; McIntosh, S. W.

    2003-05-01

    We take another look at the issue of fitting spectral lines from two different viewpoints. Firstly, we present a theoretical framework that enables the exploration of spectrometer precisions. The theory enables the discussion of theoretical precision limits to model spectrometers. Some applications of the theory are presented and discussed with reference to the Coronal Diagnostic Spectrometer (CDS) and Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instruments on board the Solar and Heliospheric Observatory (SOHO). Secondly, we discuss the application of genetic and simulated annealing algorithms to line fitting problems in the context of the theoretical framework described above. Such algorithms are of utility in providing unbiased fits in a wide variety of spectra where more traditional fitting routines have difficulty converging. This work is funded via a NASA NRA 01-OSS-01 award.

  7. New theoretical results in synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Bagrov, V. G.; Gitman, D. M.; Tlyachev, V. B.; Jarovoi, A. T.

    2005-11-01

    One of the remarkable features of the relativistic electron synchrotron radiation is its concentration in small angle Δ ≈ 1/γ (here γ-relativistic factor: γ = E/mc2, E energy, m electron rest mass, c light velocity) near rotation orbit plane [V.G. Bagrov, V.A. Bordovitsyn, V.G. Bulenok, V. Ya. Epp, Kinematical projection of pulsar synchrotron radiation profiles, in: Proceedings of IV ISTC Scientific Advisory Commitee Seminar on Basic Science in ISTC Aktivities, Akademgorodok, Novosibirsk, April 23 27, 2001, p. 293 300]. This theoretically predicted and experimentally confirmed feature is peculiar to total (spectrum summarized) radiating intensity. This angular distribution property has been supposed to be (at least qualitatively) conserved and for separate spectrum synchrotron radiation components. In the work of V.G. Bagrov, V.A. Bordovitsyn, V. Ch. Zhukovskii, Development of the theory of synchrotron radiation and related processes. Synchrotron source of JINR: the perspective of research, in: The Materials of the Second International Work Conference, Dubna, April 2 6, 2001, pp. 15 30 and in Angular dependence of synchrotron radiation intensity. http://lanl.arXiv.org/abs/physics/0209097, it is shown that the angular distribution of separate synchrotron radiation spectrum components demonstrates directly inverse tendency the angular distribution deconcentration relatively the orbit plane takes place with electron energy growth. The present work is devoted to detailed investigation of this situation. For exact quantitative estimation of angular concentration degree of synchrotron radiation the definition of radiation effective angle and deviation angle is proposed. For different polarization components of radiation the dependence of introduced characteristics was investigated as a functions of electron energy and number of spectrum component.

  8. Enantioselective Michael Addition of Water

    PubMed Central

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-01-01

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry. PMID:25529526

  9. Enantioselective Michael addition of water.

    PubMed

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-02-01

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry.

  10. Learning Information Systems: Theoretical Foundations.

    ERIC Educational Resources Information Center

    Paul, Terrance D.

    This paper uses the conceptual framework of cybernetics to understand why learning information systems such as the "Accelerated Reader" work so successfully, and to examine how this simple yet incisive concept can be used to accelerate learning at every level and in all disciplines. The first section, "Basic Concepts," discusses the cybernetic…

  11. Gasoline additives, emissions, and performance

    SciTech Connect

    1995-12-31

    The papers included in this publication deal with the influence of fuel, additive, and hardware changes on a variety of vehicle performance characteristics. Advanced techniques for measuring these performance parameters are also described. Contents include: Fleet test evaluation of gasoline additives for intake valve and combustion chamber deposit clean up; A technique for evaluating octane requirement additives in modern engines on dynamometer test stands; A fleet test of two additive technologies comparing their effects on tailpipe emissions; Investigation into the vehicle exhaust emissions of high percentage ethanol blends; Variability in hydrocarbon speciation measurements at low emission (ULEV) levels; and more.

  12. An integrated theoretical and practical approach for teaching hydrogeology

    NASA Astrophysics Data System (ADS)

    Bonomi, Tullia; Fumagalli, Letizia; Cavallin, Angelo

    2013-04-01

    their limitations; C) by an evaluation process whose results contribute to the final examination, so that the students are evaluated on the basis of their ability to discuss theoretical subjects and/or projects and to resolving exercises and case studies either by hand calculations or by modelling. The applied hydrogeology examination is an example of the evaluation process. It involves development of a plan to resolve a real hydrogeological issue, such as the design of a hydraulic barrier for a landfill, the design of a well field to meet the supply requirements of a muncipality, or the control of possible seepage from a contaminated site close to to sensitive discharge features such as wells, springs, rivers. The students are allowed to work on computers for three consecutive mornings for a total 15 hours, and in the end are required to produce a technical report and a hydrogeological model. Obviously their solutions are neither unique nor completely optimized (just as in the real world), but the comparisons and debates among the students are important portals to learning and improvement. A second example: the groundwater pollution and remediation examination is based on the discussion of a remediation project elaborated in stages during the course, with the addition of increasing complex types of data and information. The students have one hour a week, during the course, to submit to the teacher their analysis of the problem and possible solutions. In ten years of experience all students have considered this method of examination a challenge, and found it engaging and helpful, even if unusual, at least in Italy. The University of Milano Bicocca has recently drilled a piezometric well both to monitor the flow of groundwater and to allow students to perform aquifer tests and to conduct standard groundwater sampling procedure, without any longer needing to rely on outside private donors for access to a field site. The overall approach, which includes, lectures

  13. High-throughput theoretical design of lithium battery materials

    NASA Astrophysics Data System (ADS)

    Shi-Gang, Ling; Jian, Gao; Rui-Juan, Xiao; Li-Quan, Chen

    2016-01-01

    The rapid evolution of high-throughput theoretical design schemes to discover new lithium battery materials is reviewed, including high-capacity cathodes, low-strain cathodes, anodes, solid state electrolytes, and electrolyte additives. With the development of efficient theoretical methods and inexpensive computers, high-throughput theoretical calculations have played an increasingly important role in the discovery of new materials. With the help of automatic simulation flow, many types of materials can be screened, optimized and designed from a structural database according to specific search criteria. In advanced cell technology, new materials for next generation lithium batteries are of great significance to achieve performance, and some representative criteria are: higher energy density, better safety, and faster charge/discharge speed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11234013 and 51172274) and the National High Technology Research and Development Program of China (Grant No. 2015AA034201).

  14. Theoretical aspects of cephalosporin isomerism

    SciTech Connect

    Pop, E.; Brewster, M.E.; Bodor, N. Univ. of Florida, Gainesville ); Kaminski, J.J. )

    1989-01-01

    The {triangle}{sup 3} double bond of cephalosporins isomerizes to the {triangle}{sup 2} position, resulting in biological inactivation of these antibiotics. This phenomenon occurs slowly in the case of cephalosporanic acids, but is rapid when the 4-carboxylate moiety is esterified or otherwise derivatized, leading to an equilibrium between the {triangle}{sup 2} and {triangle}{sup 3} forms. A theoretical study of this isomerization is described in the framework of two semiempirical all-valence electron molecular orbital (MO) approximations, namely MNDO and AMI. Specifically, the methyl ester and free carboxylate derivatives of both the {triangle}{sup 3} and {triangle}{sup 2} isomers of 7-phenylacetamidocephalosporin were studied. The results obtained indicated that the {triangle}{sup 3} derivatives were thermodynamically more stable than were the {triangle}{sup 2} isomers both in the case of the free acids and methyl esters. These data are consistent with experimental findings and suggest that the more rapid isomerization demonstrated in the case of the esters is due primarily to kinetic rather than to thermodynamic factors. Examination of the calculated molecular structures lend support to various theories that correlate the inactivity of the {triangle}{sup 2} isomers with spatial considerations and the degree of {beta}-lactam amide resonance.

  15. Theoretical investigations of plasma processes

    NASA Technical Reports Server (NTRS)

    Wilhelm, H. E.; Hong, S. H.

    1976-01-01

    System analyses are presented for electrically sustained, collision dominated plasma centrifuges, in which the plasma rotates under the influence of the Lorentz forces resulting from the interaction of the current density fields with an external magnetic field. It is shown that gas discharge centrifuges are technically feasible in which the plasma rotates at speeds up to 1 million cm/sec. The associated centrifugal forces produce a significant spatial isotope separation, which is somewhat perturbed in the viscous boundary layers at the centrifuge walls. The isotope separation effect is the more pronounced. The induced magnetic fields have negligible influence on the plasma rotation if the Hall coefficient is small. In the technical realization of collision dominated plasma centrifuges, a trade-off has to be made between power density and speeds of rotation. The diffusion of sputtered atoms to system surfaces of ion propulsion systems and the deposition of the atoms are treated theoretically by means of a simple model which permits an analytical solution. The problem leads to an inhomogeneous integral equation.

  16. M-theoretic matrix models

    NASA Astrophysics Data System (ADS)

    Grassi, Alba; Mariño, Marcos

    2015-02-01

    Some matrix models admit, on top of the usual 't Hooft expansion, an M-theory-like expansion, i.e. an expansion at large N but where the rest of the parameters are fixed, instead of scaling with N . These models, which we call M-theoretic matrix models, appear in the localization of Chern-Simons-matter theories, and also in two-dimensional statistical physics. Generically, their partition function receives non-perturbative corrections which are not captured by the 't Hooft expansion. In this paper, we discuss general aspects of these type of matrix integrals and we analyze in detail two different examples. The first one is the matrix model computing the partition function of supersymmetric Yang-Mills theory in three dimensions with one adjoint hypermultiplet and N f fundamentals, which has a conjectured M-theory dual, and which we call the N f matrix model. The second one, which we call the polymer matrix model, computes form factors of the 2d Ising model and is related to the physics of 2d polymers. In both cases we determine their exact planar limit. In the N f matrix model, the planar free energy reproduces the expected behavior of the M-theory dual. We also study their M-theory expansion by using Fermi gas techniques, and we find non-perturbative corrections to the 't Hooft expansion.

  17. Rethinking Theoretical Approaches to Stigma

    PubMed Central

    Martin, Jack K; Lang, Annie; Olafsdottir, Sigrun

    2008-01-01

    A resurgence of research and policy efforts on stigma both facilitates and forces a reconsideration of the levels and types of factors that shape reactions to persons with conditions that engender prejudice and discrimination. Focusing on the case of mental illness but drawing from theories and studies of stigma across the social sciences, we propose a framework that brings together theoretical insights from micro, meso and macro level research: Framework Integrating Normative Influences on Stigma (FINIS) starts with Goffman’s notion that understanding stigma requires a language of social relationships, but acknowledges that individuals do not come to social interaction devoid of affect and motivation. Further, all social interactions take place in a context in which organizations, media and larger cultures structure normative expectations which create the possibility of marking “difference”. Labelling theory, social network theory, the limited capacity model of media influence, the social psychology of prejudice and discrimination, and theories of the welfare state all contribute to an understanding of the complex web of expectations shaping stigma. FINIS offers the potential to build a broad-based scientific foundation based on understanding the effects of stigma on the lives of persons with mental illness, the resources devoted to the organizations and families who care for them, and policies and programs designed to combat stigma. We end by discussing the clear implications this framework holds for stigma reduction, even in the face of conflicting results. PMID:18436358

  18. Theoretical analysis of single molecule spectroscopy lineshapes of conjugated polymers

    NASA Astrophysics Data System (ADS)

    Devi, Murali

    satisfactory fitting, it is shown that the inclusion of an additional energetic disorder is essential, representing the effect of quasi-static disorder accumulated during the SMES of each polymer. Various technical details, ambiguous issues, and implication of the present work are discussed.

  19. Color Addition and Subtraction Apps

    ERIC Educational Resources Information Center

    Ruiz, Frances; Ruiz, Michael J.

    2015-01-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…

  20. Globalization, Work, and Cardiovascular Disease.

    PubMed

    Schnall, Peter L; Dobson, Marnie; Landsbergis, Paul

    2016-10-01

    Cardiovascular disease (CVD), a global epidemic, is responsible for about 30% of all deaths worldwide. While mortality rates from CVD have been mostly declining in the advanced industrialized nations, CVD risk factors, including hypertension, obesity, and diabetes, have been on the increase everywhere. Researchers investigating the social causes of CVD have produced a robust body of evidence documenting the relationships between the work environment and CVD, including through the mechanisms of psychosocial work stressors. We review the empirical evidence linking work, psychosocial stressors, and CVD. These work stressors can produce chronic biologic arousal and promote unhealthy behaviors and thus, increased CVD risk. We offer a theoretical model that illustrates how economic globalization influences the labor market and work organization in high-income countries, which, in turn, exacerbates job characteristics, such as demands, low job control, effort-reward imbalance, job insecurity, and long work hours. There is also a growing interest in "upstream" factors among work stress researchers, including precarious employment, downsizing/restructuring, privatization, and lean production. We conclude with suggestions for future epidemiologic research on the role of work in the development of CVD, as well as policy recommendations for prevention of work-related CVD. PMID:27604540

  1. Globalization, Work, and Cardiovascular Disease.

    PubMed

    Schnall, Peter L; Dobson, Marnie; Landsbergis, Paul

    2016-10-01

    Cardiovascular disease (CVD), a global epidemic, is responsible for about 30% of all deaths worldwide. While mortality rates from CVD have been mostly declining in the advanced industrialized nations, CVD risk factors, including hypertension, obesity, and diabetes, have been on the increase everywhere. Researchers investigating the social causes of CVD have produced a robust body of evidence documenting the relationships between the work environment and CVD, including through the mechanisms of psychosocial work stressors. We review the empirical evidence linking work, psychosocial stressors, and CVD. These work stressors can produce chronic biologic arousal and promote unhealthy behaviors and thus, increased CVD risk. We offer a theoretical model that illustrates how economic globalization influences the labor market and work organization in high-income countries, which, in turn, exacerbates job characteristics, such as demands, low job control, effort-reward imbalance, job insecurity, and long work hours. There is also a growing interest in "upstream" factors among work stress researchers, including precarious employment, downsizing/restructuring, privatization, and lean production. We conclude with suggestions for future epidemiologic research on the role of work in the development of CVD, as well as policy recommendations for prevention of work-related CVD.

  2. Theoretical Issues in Strangeness Production

    SciTech Connect

    Laget, Jean-Marc

    2000-12-31

    After pioneering works on hypernuclei, strangeness production mechanisms have been studied in hadron collisions and photoreactions in the sixties. Recent experiments at SATURNE and COSY, in the hadronic sector, as well as ELSA and JLab, in the electromagnetic sector, have confirmed our basic ideas on the reaction mechanisms. In the near future, strangeness production at JLab, HERMES and COMPASS may prove to be a powerful tool to study hadronic matter.

  3. The milieu of managerial work: an integrative framework linking work context to role requirements.

    PubMed

    Dierdorff, Erich C; Rubin, Robert S; Morgeson, Frederick P

    2009-07-01

    Theoretical and empirical efforts focusing on the interplay between work context and managerial role requirements have been conspicuously absent in the scholarly literature. This paucity exists despite over 60 years of research concerning the requirements of managerial work and with the rather universal recognition that work context meaningfully shapes organizational behavior. The authors developed a theoretical model linking different types of role requirements to different forms of work context. They empirically tested this framework with a nationally representative sample of 8,633 incumbent spanning 52 managerial occupations. Findings from hierarchical linear modeling analyses demonstrated that discrete forms of context (task, social, and physical) exert significant and predictable effects on managerial role requirements.

  4. Electromechanical properties of smart aggregate: theoretical modeling and experimental validation

    NASA Astrophysics Data System (ADS)

    Wang, Jianjun; Kong, Qingzhao; Shi, Zhifei; Song, Gangbing

    2016-09-01

    Smart aggregate (SA), as a piezoceramic-based multi-functional device, is formed by sandwiching two lead zirconate titanate (PZT) patches with copper shielding between a pair of solid-machined cylindrical marble blocks with epoxy. Previous researches have successfully demonstrated the capability and reliability of versatile SAs to monitor the structural health of concrete structures. However, the previous works concentrated mainly on the applications of SAs in structural health monitoring; no reasonable theoretical model of SAs was proposed. In this paper, electromechanical properties of SAs were investigated using a proposed theoretical model. Based on one dimensional linear theory of piezo-elasticity, the dynamic solutions of a SA subjected to an external harmonic voltage were solved. Further, the electric impedance of the SA was computed, and the resonance and anti-resonance frequencies were calculated based on derived equations. Numerical analysis was conducted to discuss the effects of the thickness of epoxy layer and the dimension of PZT patch on the fundamental resonance and anti-resonance frequencies as well as the corresponding electromechanical coupling factor. The dynamic solutions based on the proposed theoretical model were further experimentally verified with two SA samples. The fundamental resonance and anti-resonance frequencies of SAs show good agreements in both theoretical and experimental results. The presented analysis and results contribute to the overall understanding of SA properties and help to optimize the working frequencies of SAs in structural health monitoring of civil structures.

  5. Pargament's Theory of Religious Coping: Implications for Spiritually Sensitive Social Work Practice

    PubMed Central

    Xu, Jianbin

    2016-01-01

    This article proposes that Pargament's theory of religious coping can be a theoretical beacon to spiritually sensitive social work practice. It begins with a discussion of the raison d'être of spiritually sensitive social work, which is examined as being able to cast a holistic and positive glow on social work. Then it provides an overview and a critique of Pargament's theory, emphasising that the theory offers a fuller and more impartial picture of religious coping. In addition, it explores the implications of Pargament's theory for spiritually sensitive social work practice with religious clients in terms of engagement, assessment and intervention. This article concludes by discussing how social work practitioners can avoid the pitfalls and limitations of Pargament's theory. PMID:27559234

  6. Color Addition and Subtraction Apps

    NASA Astrophysics Data System (ADS)

    Ruiz, Frances; Ruiz, Michael J.

    2015-10-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step in understanding mathematical representations of RGB color. Finally, color addition and subtraction are presented for the X11 colors from web design to illustrate yet another real-life application of color mixing.

  7. Theoretical and experimental studies of the stability of drug-drug interact.

    PubMed

    Soares, Monica F R; Alves, Lariza D S; Nadvorny, Daniela; Soares-Sobrinho, José L; Rolim-Neto, Pedro J

    2016-11-01

    Several factors can intervene in the molecular properties and consequently in the stability of drugs. The molecular complexes formation often occur due to favor the formation of hydrogen bonds, leading the system to configuration more energy stable. This work we aim to investigate through theoretical and experimental methods the relation between stability and properties of molecular complexes the molecular complex formed between the drugs, efavirenz (EFV), lamivudine (3TC) and zidovudine (AZT). With this study was possible determining the most stable complex formed between the compounds evaluated. In addition the energy and structural properties of the complex formed in relation to its individual components allowed us to evaluate the stability of the same. PMID:27267283

  8. Theoretical and Experimental Study of Optical Coherence Tomography (OCT) Signals Using an Analytical Transport Model

    SciTech Connect

    Vazquez Villa, A.; Delgado Atencio, J. A.; Vazquez y Montiel, S.; Cunill Rodriguez, M.; Martinez Rodriguez, A. E.; Ramos, J. Castro; Villanueva, A.

    2010-12-07

    Optical coherence tomography (OCT) is a non-invasive low coherent interferometric technique that provides cross-sectional images of turbid media. OCT is based on the classical Michelson interferometer where the mirror of the reference arm is oscillating and the signal arm contains a biological sample. In this work, we analyzed theoretically the heterodyne optical signal adopting the so called extended Huygens-Fresnel principle (EHFP). We use simulated OCT images with known optical properties to test an algorithm developed by ourselves to recover the scattering coefficient and we recovered the scattering coefficient with a relative error less than 5% for noisy signals. In addition, we applied this algorithm to OCT images from phantoms of known optical properties; in this case curves were indistinguishable. A revision of the validity of the analytical model applied to our system should be done.

  9. Theoretical & Experimental Studies of Elementary Particles

    SciTech Connect

    McFarland, Kevin

    2012-10-04

    Abstract High energy physics has been one of the signature research programs at the University of Rochester for over 60 years. The group has made leading contributions to experimental discoveries at accelerators and in cosmic rays and has played major roles in developing the theoretical framework that gives us our ``standard model'' of fundamental interactions today. This award from the Department of Energy funded a major portion of that research for more than 20 years. During this time, highlights of the supported work included the discovery of the top quark at the Fermilab Tevatron, the completion of a broad program of physics measurements that verified the electroweak unified theory, the measurement of three generations of neutrino flavor oscillations, and the first observation of a ``Higgs like'' boson at the Large Hadron Collider. The work has resulted in more than 2000 publications over the period of the grant. The principal investigators supported on this grant have been recognized as leaders in the field of elementary particle physics by their peers through numerous awards and leadership positions. Most notable among them is the APS W.K.H. Panofsky Prize awarded to Arie Bodek in 2004, the J.J. Sakurai Prizes awarded to Susumu Okubo and C. Richard Hagen in 2005 and 2010, respectively, the Wigner medal awarded to Susumu Okubo in 2006, and five principal investigators (Das, Demina, McFarland, Orr, Tipton) who received Department of Energy Outstanding Junior Investigator awards during the period of this grant. The University of Rochester Department of Physics and Astronomy, which houses the research group, provides primary salary support for the faculty and has waived most tuition costs for graduate students during the period of this grant. The group also benefits significantly from technical support and infrastructure available at the University which supports the work. The research work of the group has provided educational opportunities for graduate students

  10. Teebi hypertelorism syndrome: additional cases.

    PubMed

    Machado-Paula, Ligiane Alves; Guion-Almeida, Maria Leine

    2003-03-01

    We report on two unrelated Brazilian boys who have craniofacial and digital anomalies resembling those reported with Teebi hypertelorism syndrome. Additional features such as cleft lip and palate, large uvula, atypical chin and abnormal scapulae were observed.

  11. Decent Work: A Psychological Perspective.

    PubMed

    Blustein, David L; Olle, Chad; Connors-Kellgren, Alice; Diamonti, A J

    2016-01-01

    This contribution, which serves as the lead article for the Research Topic entitled "From Meaning of Working to Meaningful Lives: The Challenges of Expanding Decent Work," explores current challenges in the development and operationalization of decent work. Based on an initiative from the International Labor Organization [ILO] (1999) decent work represents an aspirational statement about the quality of work that should be available to all people who seek to work around the globe. Within recent years, several critiques have been raised about decent work from various disciplines, highlighting concerns about a retreat from the social justice ethos that had initially defined the concept. In addition, other scholars have observed that decent work has not included a focus on the role of meaning and purpose at work. To address these concerns, we propose that a psychological perspective can help to revitalize the decent work agenda by infusing a more specific focus on individual experiences and by reconnecting decent work to its social justice origins. As an illustration of the advantages of a psychological perspective, we explore the rise of precarious work and also connect the decent work agenda to the Psychology-of-Working Framework and Theory (Blustein, 2006; Duffy et al., 2016). PMID:27047430

  12. Decent Work: A Psychological Perspective

    PubMed Central

    Blustein, David L.; Olle, Chad; Connors-Kellgren, Alice; Diamonti, A. J.

    2016-01-01

    This contribution, which serves as the lead article for the Research Topic entitled “From Meaning of Working to Meaningful Lives: The Challenges of Expanding Decent Work,” explores current challenges in the development and operationalization of decent work. Based on an initiative from the International Labor Organization [ILO] (1999) decent work represents an aspirational statement about the quality of work that should be available to all people who seek to work around the globe. Within recent years, several critiques have been raised about decent work from various disciplines, highlighting concerns about a retreat from the social justice ethos that had initially defined the concept. In addition, other scholars have observed that decent work has not included a focus on the role of meaning and purpose at work. To address these concerns, we propose that a psychological perspective can help to revitalize the decent work agenda by infusing a more specific focus on individual experiences and by reconnecting decent work to its social justice origins. As an illustration of the advantages of a psychological perspective, we explore the rise of precarious work and also connect the decent work agenda to the Psychology-of-Working Framework and Theory (Blustein, 2006; Duffy et al., 2016). PMID:27047430

  13. Theoretical Investigations of Plasma-Based Accelerators and Other Advanced Accelerator Concepts

    SciTech Connect

    Shuets, G.

    2004-05-21

    Theoretical investigations of plasma-based accelerators and other advanced accelerator concepts. The focus of the work was on the development of plasma based and structure based accelerating concepts, including laser-plasma, plasma channel, and microwave driven plasma accelerators.

  14. Work and Sleep—A Prospective Study of Psychosocial Work Factors, Physical Work Factors, and Work Scheduling

    PubMed Central

    Åkerstedt, Torbjörn; Garefelt, Johanna; Richter, Anne; Westerlund, Hugo; Magnusson Hanson, Linda L.; Sverke, Magnus; Kecklund, Göran

    2015-01-01

    Study Objectives: There is limited knowledge about the prospective relationship between major work characteristics (psychosocial, physical, scheduling) and disturbed sleep. The current study sought to provide such knowledge. Design: Prospective cohort, with measurements on two occasions (T1 and T2) separated by two years. Setting: Naturalistic study, Sweden. Participants: There were 4,827 participants forming a representative sample of the working population. Measurements and Results: Questionnaire data on work factors obtained on two occasions were analyzed with structural equation modeling. Competing models were compared in order to investigate temporal relationships. A reciprocal model was found to fit the data best. Sleep disturbances at T2 were predicted by higher work demands at T1 and by lower perceived stress at T1. In addition, sleep disturbances at T1 predicted subsequent higher perception of stress, higher work demands, lower degree of control, and less social support at work at T2. A cross-sectional mediation analysis showed that (higher) perceived stress mediated the relationship between (higher) work demands and sleep disturbances; however, no such association was found longitudinally. Conclusions: Higher work demands predicted disturbed sleep, whereas physical work characteristics, shift work, and overtime did not. In addition, disturbed sleep predicted subsequent higher work demands, perceived stress, less social support, and lower degree of control. The results suggest that remedial interventions against sleep disturbances should focus on psychosocial factors, and that such remedial interventions may improve the psychosocial work situation in the long run. Citation: Åkerstedt T, Garefelt J, Richter A, Westerlund H, Magnusson LL, Sverke M, Kecklund G. Work and sleep—a prospective study of psychosocial work factors, physical work factors, and work scheduling. SLEEP 2015;38(7):1129–1136. PMID:26118559

  15. Polyolefins as additives in plastics

    SciTech Connect

    Deanin, R.D.

    1993-12-31

    Polyolefins are not only major commodity plastics - they are also very useful as additives, both in other polyolefins and also in other types of plastics. This review covers ethylene, propylene, butylene and isobutylene polymers, in blends with each other, and as additives to natural rubber, styrene/butadiene rubber, polystyrene, polyvinyl chloride, polymethyl methacrylate, polyphenylene oxide, polycarbonate, thermoplastic polyesters, polyurethanes, polyamides, and mixed automotive plastics recycling.

  16. Theoretical limits on barreling of cylinders under axisymmetric compression

    NASA Astrophysics Data System (ADS)

    Fournier, Jorge L. Velez; Banerjee, Jayanta K.

    2012-06-01

    A theoretical analysis on three different geometrical limits during axial compression of a cylindrical workpiece under monotonically increasing external load is presented. Barreling is the main factor in metalworking industries, and it depends highly on several dimensional ratios such as initial aspect ratio (height/diameter), work/platen contact diameter ratios, etc. For a known material, barreling can be predicted from the mathematical formulations on the geometrical limits presented herein.

  17. Theoretical considerations and measurements for phoropters

    NASA Astrophysics Data System (ADS)

    Zhang, Jiyan; Liu, Wenli; Sun, Jie

    2008-10-01

    A phoropter is one of the most popular ophthalmic instruments used in current optometry practice. The quality and verification of the instrument are of the utmost importance. In 1997, International Organization for Standardization published the first ISO standard for requirements of phoropters. However, in China, few standard and test method are suggested for phoropters. Research work on test method for phoropters was carried out early in 2004 by China National Institute of Metrology. In this paper, first, structure of phoropters is described. Then, theoretical considerations for its optical design are analyzed. Next, a newly developed instrument is introduced and measurements are taken. By calibration, the indication error of the instrument is not over 0.05m-1. Finally, measurement results show that the quality situation of phoropters is not as good as expected because of production and assembly error. Optical design shall be improved especially for combinations of both spherical and cylindrical lenses with higher power. Besides, optical requirements specified in ISO standard are found to be a little strict and hard to meet. A proposal for revision of this international standard is drafted and discussed on ISO meeting of 2007 held in Tokyo.

  18. A theoretical analysis of vertical flow equilibrium

    SciTech Connect

    Yortsos, Y.C.

    1992-01-01

    The assumption of Vertical Flow Equilibrium (VFE) and of parallel flow conditions, in general, is often applied to the modeling of flow and displacement in natural porous media. However, the methodology for the development of the various models is rather intuitive, and no rigorous method is currently available. In this paper, we develop an asymptotic theory using as parameter the variable R{sub L} = (L/H){radical}(k{sub V})/(k{sub H}). It is rigorously shown that present models represent the leading order term of an asymptotic expansion with respect to 1/R{sub L}{sup 2}. Although this was numerically suspected, it is the first time that is is theoretically proved. Based on the general formulation, a series of models are subsequently obtained. In the absence of strong gravity effects, they generalize previous works by Zapata and Lake (1981), Yokoyama and Lake (1981) and Lake and Hirasaki (1981), on immiscible and miscible displacements. In the limit of gravity-segregated flow, we prove conditions for the fluids to be segregated and derive the Dupuit and Dietz (1953) approximations. Finally, we also discuss effects of capillarity and transverse dispersion.

  19. Theoretical design of an energy recovering divertor

    NASA Astrophysics Data System (ADS)

    Baver, D. A.

    2010-11-01

    An energy recovering divertor (ERD) is a device for converting thermal to electrical energy in the divertor channel of a tokamak. Because ERD's are a type of heat engine operating at plasma temperatures, they have the thermodynamic potential for extremely high efficiencies. An ERD offers several important benefits to a tokamak fusion reactor. First, any energy recovered by the ERD is subtracted from divertor heat load, thus circumventing materials limitations. Second, energy recovered by the ERD is available for auxiliary heating, thus allowing the reactor to break even at a lower Lawson parameter. Third, an ERD can be used to power auxiliary current drive, thus reducing dependence on bootstrap current. We will present a design for an ERD based on amplification of Alfven waves in a manner analogous to a free-electron laser. While its projected efficiency falls short of the thermodynamic potential for this class of device, it nonetheless demonstrates the theoretical viability of direct power conversion in a tokamak divertor. We will also present potential approaches towards higher efficiency devices of this type. Work supported by the U.S. DOE under grant DE-FG02-97ER54392.

  20. Food additives and preschool children.

    PubMed

    Martyn, Danika M; McNulty, Breige A; Nugent, Anne P; Gibney, Michael J

    2013-02-01

    Food additives have been used throughout history to perform specific functions in foods. A comprehensive framework of legislation is in place within Europe to control the use of additives in the food supply and ensure they pose no risk to human health. Further to this, exposure assessments are regularly carried out to monitor population intakes and verify that intakes are not above acceptable levels (acceptable daily intakes). Young children may have a higher dietary exposure to chemicals than adults due to a combination of rapid growth rates and distinct food intake patterns. For this reason, exposure assessments are particularly important in this age group. The paper will review the use of additives and exposure assessment methods and examine factors that affect dietary exposure by young children. One of the most widely investigated unfavourable health effects associated with food additive intake in preschool-aged children are suggested adverse behavioural effects. Research that has examined this relationship has reported a variety of responses, with many noting an increase in hyperactivity as reported by parents but not when assessed using objective examiners. This review has examined the experimental approaches used in such studies and suggests that efforts are needed to standardise objective methods of measuring behaviour in preschool children. Further to this, a more holistic approach to examining food additive intakes by preschool children is advisable, where overall exposure is considered rather than focusing solely on behavioural effects and possibly examining intakes of food additives other than food colours.

  1. Theoretical Study of OH Reaction with Toluene

    NASA Astrophysics Data System (ADS)

    Suh, I.; Zhang, D.; Zhang, R.; Molina, L. T.; Molina, M. J.

    2001-12-01

    Aromatic hydrocarbons constitute a major faction of total volatile organic compounds (VOCs) in the urban and regional atmosphere, and are emitted primarily from anthropogenic sources, i.e. emission from automobiles, fuel-based vehicles, and industry. In addition to their important role in gas-phase chemistry of urban air pollution, oxidation of aromatic hydrocarbons leads to formation of various non-volatile and semi-volatile organic compounds, which are responsible for the formation of secondary organic aerosols. Toluene is the most abundant aromatic hydrocarbon. Reactions of toluene in the atmosphere are mainly initiated by attack from hydroxyl radical OH. In this study, we report a theoretical study of the reaction of toluene with OH. Density functional theory (DFT) and ab initio calculations have been employed to investigate the OH-toluene adduct isomers. The geometries and energetics of the four isomers of the OH-toluene adduct radicals as well as their corresponding transition states are presented. The DFT and ab initio theories applicable to the OH-toluene reaction system are evaluated. We also present calculations of the rate constants and isomeric branching ratios of the formation of the OH-toluene adduct isomers.

  2. Parameters and error of a theoretical model

    SciTech Connect

    Moeller, P.; Nix, J.R.; Swiatecki, W.

    1986-09-01

    We propose a definition for the error of a theoretical model of the type whose parameters are determined from adjustment to experimental data. By applying a standard statistical method, the maximum-likelihoodlmethod, we derive expressions for both the parameters of the theoretical model and its error. We investigate the derived equations by solving them for simulated experimental and theoretical quantities generated by use of random number generators. 2 refs., 4 tabs.

  3. Experimental and Theoretical Analysis of Central H{sub {beta}} Asymmetry

    SciTech Connect

    Demura, A. V.; Demchenko, G. V.; Djurovic, S.; Cirisan, M.; Nikolic, D.; Gigosos, M. A.; Gonzalez, M. A.

    2008-10-22

    The hydrogen Balmer beta line is used as a plasma diagnostics tool for a long time. It is well known that the experimental profiles of H{sub {beta}} line exhibit an asymmetry while some of most commonly used theoretical models, due to the employed approximations, give unshifted and symmetrical profiles. In the present work the central part of H{sub {beta}} profile is reanalyzed experimentally and in terms of two theoretical approaches based correspondingly on the Standard Theory (ST) assumptions and on the electric field computer simulation method. The present experimental and theoretical results are compared with the obtained earlier experimental and theoretical data.

  4. A theoretical and experimental investigation of graph theoretical measures for land development in satellite imagery.

    PubMed

    Unsalan, Cem; Boyer, Kim L

    2005-04-01

    Today's commercial satellite images enable experts to classify region types in great detail. In previous work, we considered discriminating rural and urban regions [23]. However, a more detailed classification is required for many purposes. These fine classifications assist government agencies in many ways including urban planning, transportation management, and rescue operations. In a step toward the automation of the fine classification process, this paper explores graph theoretical measures over grayscale images. The graphs are constructed by assigning photometric straight line segments to vertices, while graph edges encode their spatial relationships. We then introduce a set of measures based on various properties of the graph. These measures are nearly monotonic (positively correlated) with increasing structure (organization) in the image. Thus, increased cultural activity and land development are indicated by increases in these measures-without explicit extraction of road networks, buildings, residences, etc. These latter, time consuming (and still only partially automated) tasks can be restricted only to "promising" image regions, according to our measures. In some applications our measures may suffice. We present a theoretical basis for the measures followed by extensive experimental results in which the measures are first compared to manual evaluations of land development. We then present and test a method to focus on, and (pre)extract, suburban-style residential areas. These are of particular importance in many applications, and are especially difficult to extract. In this work, we consider commercial IKONOS data. These images are orthorectified to provide a fixed resolution of 1 meter per pixel on the ground. They are, therefore, metric in the sense that ground distance is fixed in scale to pixel distance. Our data set is large and diverse, including sea and coastline, rural, forest, residential, industrial, and urban areas.

  5. Identifiability of Additive, Time-Varying Actuator and Sensor Faults by State Augmentation

    NASA Technical Reports Server (NTRS)

    Upchurch, Jason M.; Gonzalez, Oscar R.; Joshi, Suresh M.

    2014-01-01

    Recent work has provided a set of necessary and sucient conditions for identifiability of additive step faults (e.g., lock-in-place actuator faults, constant bias in the sensors) using state augmentation. This paper extends these results to an important class of faults which may affect linear, time-invariant systems. In particular, the faults under consideration are those which vary with time and affect the system dynamics additively. Such faults may manifest themselves in aircraft as, for example, control surface oscillations, control surface runaway, and sensor drift. The set of necessary and sucient conditions presented in this paper are general, and apply when a class of time-varying faults affects arbitrary combinations of actuators and sensors. The results in the main theorems are illustrated by two case studies, which provide some insight into how the conditions may be used to check the theoretical identifiability of fault configurations of interest for a given system. It is shown that while state augmentation can be used to identify certain fault configurations, other fault configurations are theoretically impossible to identify using state augmentation, giving practitioners valuable insight into such situations. That is, the limitations of state augmentation for a given system and configuration of faults are made explicit. Another limitation of model-based methods is that there can be large numbers of fault configurations, thus making identification of all possible configurations impractical. However, the theoretical identifiability of known, credible fault configurations can be tested using the theorems presented in this paper, which can then assist the efforts of fault identification practitioners.

  6. Extension of the standard addition method by blank addition.

    PubMed

    Steliopoulos, Panagiotis

    2015-01-01

    Standard addition involves adding varying amounts of the analyte to sample portions of fixed mass or fixed volume and submitting those portions to the sample preparation procedure. After measuring the final extract solutions, the observed signals are linearly regressed on the spiked amounts. The original unknown amount is estimated by the opposite of the abscissa intercept of the fitted straight line [1]. A limitation of this method is that only data points with abscissa values equal to and greater than zero are available so that there is no information on whether linearity holds below the spiking level zero. An approach to overcome this limitation is introduced.•Standard addition is combined with blank addition.•Blank addition means that defined mixtures of blank matrix and sample material are subjected to sample preparation to give final extract solutions.•Equations are presented to estimate the original unknown amount and to calculate the 1-2α confidence interval about this estimate using the combined data set.

  7. ADDITIVITY ASSESSMENT OF TRIHALOMETHANE MIXTURES BY PROPORTIONAL RESPONSE ADDITION

    EPA Science Inventory

    If additivity is known or assumed, the toxicity of a chemical mixture may be predicted from the dose response curves of the individual chemicals comprising the mixture. As single chemical data are abundant and mixture data sparse, mixture risk methods that utilize single chemical...

  8. Extension of the standard addition method by blank addition

    PubMed Central

    Steliopoulos, Panagiotis

    2015-01-01

    Standard addition involves adding varying amounts of the analyte to sample portions of fixed mass or fixed volume and submitting those portions to the sample preparation procedure. After measuring the final extract solutions, the observed signals are linearly regressed on the spiked amounts. The original unknown amount is estimated by the opposite of the abscissa intercept of the fitted straight line [1]. A limitation of this method is that only data points with abscissa values equal to and greater than zero are available so that there is no information on whether linearity holds below the spiking level zero. An approach to overcome this limitation is introduced.•Standard addition is combined with blank addition.•Blank addition means that defined mixtures of blank matrix and sample material are subjected to sample preparation to give final extract solutions.•Equations are presented to estimate the original unknown amount and to calculate the 1-2α confidence interval about this estimate using the combined data set. PMID:26844210

  9. Theoretical studies in elementary particle physics. Annual technical progress report

    SciTech Connect

    Collins, J.

    1994-07-01

    This is a report on research conducted at Penn State University under grant number DE-FG02-90ER-40577, from November 1992 to present. The author is a member of the CTEQ collaboration (Coordinated Theoretical and Experimental Project on Quantitative QCD). Some of the work in CTEQ is described in this report. Topics which the authors work has touched include: polarized hard scattering; hard diffraction; small x and perturbative pomeron physics; gauge-invariant operators; fundamental QCD; heavy quarks; instantons and deep inelastic scattering; non-perturbative corrections to {tau} decay.

  10. Theoretical Modeling of Mechanical-Electrical Coupling of Carbon Nanotubes

    SciTech Connect

    Lu, Jun-Qiang; Jiang, Hanqiang

    2008-01-01

    Carbon nanotubes have been studied extensively due to their unique properties, ranging from electrical, mechanical, optical, to thermal properties. The coupling between the electrical and mechanical properties of carbon nanotubes has emerged as a new field, which raises both interesting fundamental problems and huge application potentials. In this article, we will review our recently work on the theoretical modeling on mechanical-electrical coupling of carbon nanotubes subject to various loading conditions, including tension/compression, torsion, and squashing. Some related work by other groups will be also mentioned.

  11. Theoretical Modeling of Interstellar Chemistry

    NASA Technical Reports Server (NTRS)

    Charnley, Steven

    2009-01-01

    The chemistry of complex interstellar organic molecules will be described. Gas phase processes that may build large carbon-chain species in cold molecular clouds will be summarized. Catalytic reactions on grain surfaces can lead to a large variety of organic species, and models of molecule formation by atom additions to multiply-bonded molecules will be presented. The subsequent desorption of these mixed molecular ices can initiate a distinctive organic chemistry in hot molecular cores. The general ion-molecule pathways leading to even larger organics will be outlined. The predictions of this theory will be compared with observations to show how possible organic formation pathways in the interstellar medium may be constrained. In particular, the success of the theory in explaining trends in the known interstellar organics, in predicting recently-detected interstellar molecules, and, just as importantly, non-detections, will be discussed.

  12. [INVITED] Lasers in additive manufacturing

    NASA Astrophysics Data System (ADS)

    Pinkerton, Andrew J.

    2016-04-01

    Additive manufacturing is a topic of considerable ongoing interest, with forecasts predicting it to have major impact on industry in the future. This paper focusses on the current status and potential future development of the technology, with particular reference to the role of lasers within it. It begins by making clear the types and roles of lasers in the different categories of additive manufacturing. This is followed by concise reviews of the economic benefits and disadvantages of the technology, current state of the market and use of additive manufacturing in different industries. Details of these fields are referenced rather than expanded in detail. The paper continues, focusing on current indicators to the future of additive manufacturing. Barriers to its development, trends and opportunities in major industrial sectors, and wider opportunities for its development are covered. Evidence indicates that additive manufacturing may not become the dominant manufacturing technology in all industries, but represents an excellent opportunity for lasers to increase their influence in manufacturing as a whole.

  13. Evaluation of certain food additives.

    PubMed

    2015-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, and to prepare specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for eight food additives (Benzoe tonkinensis; carrageenan; citric and fatty acid esters of glycerol; gardenia yellow; lutein esters from Tagetes erecta; octenyl succinic acid-modified gum arabic; octenyl succinic acid-modified starch; paprika extract; and pectin) and eight groups of flavouring agents (aliphatic and alicyclic hydrocarbons; aliphatic and aromatic ethers; ionones and structurally related substances; miscellaneous nitrogen-containing substances; monocyclic and bicyclic secondary alcohols, ketones and related esters; phenol and phenol derivatives; phenyl-substituted aliphatic alcohols and related aldehydes and esters; and sulfur-containing heterocyclic compounds). Specifications for the following food additives were revised: citric acid; gellan gum; polyoxyethylene (20) sorbitan monostearate; potassium aluminium silicate; and Quillaia extract (Type 2). Annexed to the report are tables summarizing the Committee's recommendations for dietary exposures to and toxicological evaluations of all of the food additives and flavouring agents considered at this meeting.

  14. Clinical effects of sulphite additives.

    PubMed

    Vally, H; Misso, N L A; Madan, V

    2009-11-01

    Sulphites are widely used as preservative and antioxidant additives in the food and pharmaceutical industries. Topical, oral or parenteral exposure to sulphites has been reported to induce a range of adverse clinical effects in sensitive individuals, ranging from dermatitis, urticaria, flushing, hypotension, abdominal pain and diarrhoea to life-threatening anaphylactic and asthmatic reactions. Exposure to the sulphites arises mainly from the consumption of foods and drinks that contain these additives; however, exposure may also occur through the use of pharmaceutical products, as well as in occupational settings. While contact sensitivity to sulphite additives in topical medications is increasingly being recognized, skin reactions also occur after ingestion of or parenteral exposure to sulphites. Most studies report a 3-10% prevalence of sulphite sensitivity among asthmatic subjects following ingestion of these additives. However, the severity of these reactions varies, and steroid-dependent asthmatics, those with marked airway hyperresponsiveness, and children with chronic asthma, appear to be at greater risk. In addition to episodic and acute symptoms, sulphites may also contribute to chronic skin and respiratory symptoms. To date, the mechanisms underlying sulphite sensitivity remain unclear, although a number of potential mechanisms have been proposed. Physicians should be aware of the range of clinical manifestations of sulphite sensitivity, as well as the potential sources of exposure. Minor modifications to diet or behaviour lead to excellent clinical outcomes for sulphite-sensitive individuals.

  15. Comparison of experimental with theoretical total-pressure loss in parallel-walled turbojet combustors

    NASA Technical Reports Server (NTRS)

    Dittrich, Ralph T

    1957-01-01

    An experimental investigation of combustor total-pressure loss was undertaken to confirm previous theoretical analyses of effects of geometric and flow variables and of heat addition. The results indicate that a reasonable estimate of cold-flow total-pressure-loss coefficient may be obtained from the theoretical analyses. Calculated total-pressure loss due to heat addition agreed with experimental data only when there was no flame ejection from the liner at the upstream air-entry holes.

  16. Defining Disability for Women and the Problem of Unpaid Work.

    ERIC Educational Resources Information Center

    Reisine, Susan T.; Fifield, Judith

    1988-01-01

    Discusses political, theoretical, and methodological issues in defining and measuring paid and unpaid work disability. Presents results of study analyzing disability in paid work and unpaid family work among 206 women with rheumatoid arthritis, demonstrating feasibility of measuring disability in family work and showing that women experience…

  17. Understanding bimolecular machines: Theoretical and experimental approaches

    NASA Astrophysics Data System (ADS)

    Goler, Adam Scott

    This dissertation concerns the study of two classes of molecular machines from a physical perspective: enzymes and membrane proteins. Though the functions of these classes of proteins are different, they each represent important test-beds from which new understanding can be developed by the application of different techniques. HIV1 Reverse Transcriptase is an enzyme that performs multiple functions, including reverse transcription of RNA into an RNA/DNA duplex, RNA degradation by the RNaseH domain, and synthesis of dsDNA. These functions allow for the incorporation of the retroviral genes into the host genome. Its catalytic cycle requires repeated large-scale conformational changes fundamental to its mechanism. Motivated by experimental work, these motions were studied theoretically by the application of normal mode analysis. It was observed that the lowest order modes correlate with largest amplitude (low-frequency) motion, which are most likely to be catalytically relevant. Comparisons between normal modes obtained via an elastic network model to those calculated from the essential dynamics of a series of all-atom molecular dynamics simulations show the self-consistency between these calculations. That similar conformational motions are seen between independent theoretical methods reinforces the importance of large-scale subdomain motion for the biochemical action of DNA polymerases in general. Moreover, it was observed that the major subunits of HIV1 Reverse Transcriptase interact quasi-harmonically. The 5HT3A Serotonin receptor and P2X1 receptor, by contrast, are trans-membrane proteins that function as ligand gated ion channels. Such proteins feature a central pore, which allows for the transit of ions necessary for cellular function across a membrane. The pore is opened by the ligation of binding sites on the extracellular portion of different protein subunits. In an attempt to resolve the individual subunits of these membrane proteins beyond the diffraction

  18. Relativistic Navigation: A Theoretical Foundation

    NASA Technical Reports Server (NTRS)

    Turyshev, Slava G.

    1996-01-01

    We present a theoretical foundation for relativistic astronomical measurements in curved space-time. In particular, we discuss a new iterative approach for describing the dynamics of an isolated astronomical N-body system in metric theories of gravity. To do this, we generalize the Fock-Chandrasekhar method of the weak-field and slow-motion approximation (WFSMA) and develop a theory of relativistic reference frames (RF's) for a gravitationally bounded many-extended-body problem. In any proper RF constructed in the immediate vicinity of an arbitrary body, the N-body solutions of the gravitational field equations are formally presented as a sum of the Riemann-flat inertial space-time, the gravitational field generated by the body itself, the unperturbed solutions for each body in the system transformed to the coordinates of this proper RF, and the gravitational interaction term. We develop the basic concept of a general WFSMA theory of the celestial RF's applicable to a wide class of metric theories of gravity and an arbitrary model of matter distribution. We apply the proposed method to general relativity. Celestial bodies are described using a perfect fluid model; as such, they possess any number of internal mass and current multipole moments that explicitly characterize their internal structures. The obtained relativistic corrections to the geodetic equations of motion arise because of a coupling of the bodies' multiple moments to the surrounding gravitational field. The resulting relativistic transformations between the different RF's extend the Poincare group to the motion of deformable self-gravitating bodies. Within the present accuracy of astronomical measurements we discuss the properties of the Fermi-normal-like proper RF that is defined in the immediate vicinity of the extended compact bodies. We further generalize the proposed approximation method and include two Eddington parameters (gamma, Beta). This generalized approach was used to derive the

  19. Additive manufacturing in production: challenges and opportunities

    NASA Astrophysics Data System (ADS)

    Ahuja, Bhrigu; Karg, Michael; Schmidt, Michael

    2015-03-01

    Additive manufacturing, characterized by its inherent layer by layer fabrication methodology has been coined by many as the latest revolution in the manufacturing industry. Due to its diversification of Materials, processes, system technology and applications, Additive Manufacturing has been synonymized with terminology such as Rapid prototyping, 3D printing, free-form fabrication, Additive Layer Manufacturing, etc. A huge media and public interest in the technology has led to an innovative attempt of exploring the technology for applications beyond the scope of the traditional engineering industry. Nevertheless, it is believed that a critical factor for the long-term success of Additive Manufacturing would be its ability to fulfill the requirements defined by the traditional manufacturing industry. A parallel development in market trends and product requirements has also lead to a wider scope of opportunities for Additive Manufacturing. The presented paper discusses some of the key challenges which are critical to ensure that Additive Manufacturing is truly accepted as a mainstream production technology in the industry. These challenges would highlight on various aspects of production such as product requirements, process management, data management, intellectual property, work flow management, quality assurance, resource planning, etc. In Addition, changing market trends such as product life cycle, mass customization, sustainability, environmental impact and localized production will form the foundation for the follow up discussion on the current limitations and the corresponding research opportunities. A discussion on ongoing research to address these challenges would include topics like process monitoring, design complexity, process standardization, multi-material and hybrid fabrication, new material development, etc.

  20. Additive Manufacturing of Hybrid Circuits

    NASA Astrophysics Data System (ADS)

    Sarobol, Pylin; Cook, Adam; Clem, Paul G.; Keicher, David; Hirschfeld, Deidre; Hall, Aaron C.; Bell, Nelson S.

    2016-07-01

    There is a rising interest in developing functional electronics using additively manufactured components. Considerations in materials selection and pathways to forming hybrid circuits and devices must demonstrate useful electronic function; must enable integration; and must complement the complex shape, low cost, high volume, and high functionality of structural but generally electronically passive additively manufactured components. This article reviews several emerging technologies being used in industry and research/development to provide integration advantages of fabricating multilayer hybrid circuits or devices. First, we review a maskless, noncontact, direct write (DW) technology that excels in the deposition of metallic colloid inks for electrical interconnects. Second, we review a complementary technology, aerosol deposition (AD), which excels in the deposition of metallic and ceramic powder as consolidated, thick conformal coatings and is additionally patternable through masking. Finally, we show examples of hybrid circuits/devices integrated beyond 2-D planes, using combinations of DW or AD processes and conventional, established processes.

  1. Postmarketing surveillance of food additives.

    PubMed

    Butchko, H H; Tschanz, C; Kotsonis, F N

    1994-08-01

    Postmarketing surveillance of consumption and of anecdotal reports of adverse health effects has been recognized by a number of regulatory authorities as a potentially useful method to provide further assurance of the safety of new food additives. Surveillance of consumption is used to estimate more reliably actual consumption levels relative to the acceptable daily intake of a food additive. Surveillance of anecdotal reports of adverse health effects is used to determine the presence of infrequent idiosyncratic responses that may not be predictable from premarket evaluations. The high-intensity sweetner, aspartame, is a food additive that has been the subject of extensive evaluation during the postmarketing period and is thus used as an example to discuss postmarketing surveillance.

  2. Random sequential addition of hard spheres in high Euclidean dimensions

    NASA Astrophysics Data System (ADS)

    Torquato, S.; Uche, O. U.; Stillinger, F. H.

    2006-12-01

    Sphere packings in high dimensions have been the subject of recent theoretical interest. Employing numerical and theoretical methods, we investigate the structural characteristics of random sequential addition (RSA) of congruent spheres in d -dimensional Euclidean space Rd in the infinite-time or saturation limit for the first six space dimensions (1≤d≤6) . Specifically, we determine the saturation density, pair correlation function, cumulative coordination number and the structure factor in each of these dimensions. We find that for 2≤d≤6 , the saturation density ϕs scales with dimension as ϕs=c1/2d+c2d/2d , where c1=0.202048 and c2=0.973872 . We also show analytically that the same density scaling is expected to persist in the high-dimensional limit, albeit with different coefficients. A byproduct of this high-dimensional analysis is a relatively sharp lower bound on the saturation density for any d given by ϕs≥(d+2)(1-S0)/2d+1 , where S0ɛ[0,1] is the structure factor at k=0 (i.e., infinite-wavelength number variance) in the high-dimensional limit. We demonstrate that a Palàsti-type conjecture (the saturation density in Rd is equal to that of the one-dimensional problem raised to the d th power) cannot be true for RSA hyperspheres. We show that the structure factor S(k) must be analytic at k=0 and that RSA packings for 1≤d≤6 are nearly “hyperuniform.” Consistent with the recent “decorrelation principle,” we find that pair correlations markedly diminish as the space dimension increases up to six. We also obtain kissing (contact) number statistics for saturated RSA configurations on the surface of a d -dimensional sphere for dimensions 2≤d≤5 and compare to the maximal kissing numbers in these dimensions. We determine the structure factor exactly for the related “ghost” RSA packing in Rd and demonstrate that its distance from “hyperuniformity” increases as the space dimension increases, approaching a constant asymptotic value

  3. Tougher Addition Polyimides Containing Siloxane

    NASA Technical Reports Server (NTRS)

    St. Clair, T. L.; Maudgal, S.

    1986-01-01

    Laminates show increased impact resistances and other desirable mechanical properties. Bismaleamic acid extended by reaction of diaminosiloxane with maleic anhydride in 1:1 molar ratio, followed by reaction with half this molar ratio of aromatic dianhydride. Bismaleamic acid also extended by reaction of diaminosiloxane with maleic anhydride in 1:2 molar ratio, followed by reaction with half this molar ratio of aromatic diamine (Michael-addition reaction). Impact resistances improved over those of unmodified bismaleimide, showing significant increase in toughness. Aromatic addition polyimides developed as both matrix and adhesive resins for applications on future aircraft and spacecraft.

  4. Additive manufacturing of glass for optical applications

    NASA Astrophysics Data System (ADS)

    Luo, Junjie; Gilbert, Luke J.; Bristow, Douglas A.; Landers, Robert G.; Goldstein, Jonathan T.; Urbas, Augustine M.; Kinzel, Edward C.

    2016-04-01

    Glasses including fused quartz have significant scientific and engineering applications including optics, communications, electronics, and hermetic seals. This paper investigates a filament fed process for Additive Manufacturing (AM) of fused quartz. Additive manufacturing has several potential benefits including increased design freedom, faster prototyping, and lower processing costs for small production volumes. However, current research in AM of glasses is limited and has focused on non-optical applications. Fused quartz is studied here because of its desirability for high-quality optics due to its high transmissivity and thermal stability. Fused quartz also has a higher working temperature than soda lime glass which poses a challenge for AM. In this work, fused quartz filaments are fed into a CO2 laser generated melt pool, smoothly depositing material onto the work piece. Single tracks are printed to explore the effects that different process parameters have on the morphology of printed fused quartz. A spectrometer is used to measure the thermal radiation incandescently emitted from the melt pool. Thin-walls are printed to study the effects of layer-to-layer height. Finally, a 3D fused quartz cube is printed using the newly acquired layer height and polished on each surface. The transmittance and index homogeneity of the polished cube are both measured. These results show that the filament fed process has the potential to print fused quartz with optical transparency and of index of refraction uniformity approaching bulk processed glass.

  5. Social Stressors at Work, Sleep, and Recovery.

    PubMed

    Pereira, Diana; Gross, Sven; Elfering, Achim

    2016-03-01

    Many employees in service work are required to work on Saturdays, recovering during work-free Sundays and working again Mondays. We examined the effects of social stressors at work on recovery status at Sunday noon and Monday noon, and investigated if sleep quality mediates the negative effects of social stressors at work on recovery. From Saturday until Monday morning, 41 participants wore actigraphs to measure sleep duration and sleep fragmentation. Social stressors at work were assessed by self-reported questionnaires administered on Saturday. Recovery status was reported Sunday noon and Monday noon. Hierarchical regression analysis revealed that social stressors at work were negatively related to recovery status on Sunday and on Monday. Supporting our assumptions, more social stressors at work predicted higher sleep fragmentation in the night to Monday. A mediation effect of sleep quality, however, was not found. Theoretical and practical implications of these results are discussed.

  6. On the Worthwhileness of Theoretical Activities

    ERIC Educational Resources Information Center

    Hand, Michael

    2009-01-01

    R.S. Peters' arguments for the worthwhileness of theoretical activities are intended to justify education per se, on the assumption that education is necessarily a matter of initiating people into theoretical activities. If we give up this assumption, we can ask whether Peters' arguments might serve instead to justify the academic curriculum over…

  7. Beauty baryon decays: a theoretical overview

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Ming

    2014-11-01

    I overview the theoretical status and recent progress on the calculations of beauty baryon decays focusing on the QCD aspects of the exclusive semi-leptonic Λb → plμ decay at large recoil and theoretical challenges of radiative and electro-weak penguin decays Λb → Λγ,Λl+l-.

  8. Lubricating additive for drilling muds

    SciTech Connect

    Gutierrez, A.; Brois, S. J.; Brownawell, D. W.; Walker, T. O.

    1985-01-01

    Aqueous drilling fluids containing a minor amount of an additive composition featuring oxazolines of C/sub 1/-C/sub 30/ alkylthioglycolic acid. Such fluids are especially useful where reduced torque drilling fluids are needed. Another embodiment of this invention relates to a method of drilling utilizing the above-described fluids.

  9. Tetrasulfide extreme pressure lubricant additives

    SciTech Connect

    Gast, L.E.; Kenney, H.E.; Schwab, A.W.

    1980-08-19

    A novel class of compounds has been prepared comprising the tetrasulfides of /sup 18/C hydrocarbons, /sup 18/C fatty acids, and /sup 18/C fatty and alkyl and triglyceride esters. These tetrasulfides are useful as extreme pressure lubricant additives and show potential as replacements for sulfurized sperm whale oil.

  10. Promoting Additive Acculturation in Schools.

    ERIC Educational Resources Information Center

    Gibson, Margaret A.

    1995-01-01

    A study focusing on 113 ninth graders of Mexican descent indicates that most students and their parents adhere to a strategy of additive acculturation (incorporating skills of the new culture and language), but that the school curriculum and general school climate devalue Mexican culture. (SLD)

  11. Individualized Additional Instruction for Calculus

    ERIC Educational Resources Information Center

    Takata, Ken

    2010-01-01

    College students enrolling in the calculus sequence have a wide variance in their preparation and abilities, yet they are usually taught from the same lecture. We describe another pedagogical model of Individualized Additional Instruction (IAI) that assesses each student frequently and prescribes further instruction and homework based on the…

  12. Tinkertoy Color-Addition Device.

    ERIC Educational Resources Information Center

    Ferguson, Joe L.

    1995-01-01

    Describes construction and use of a simple home-built device, using an overhead projector, for use in demonstrations of the addition of various combinations of red, green, and blue light. Useful in connection with discussions of color, color vision, or color television. (JRH)

  13. Additional Financial Resources for Education.

    ERIC Educational Resources Information Center

    Hubbard, Ben C.

    This paper discusses the continuing need for additional educational funds and suggests that the only way to gain these funds is through concerted and persistent political efforts by supporters of education at both the federal and state levels. The author first points out that for many reasons declining enrollment may not decrease operating costs…

  14. Theoretical studies of non-Newtonian and Newtonian fluid flow through porous media

    SciTech Connect

    Wu, Yu-Shu.

    1990-02-01

    A comprehensive theoretical study has been carried out on the flow behavior of both single and multiple phase non-Newtonian fluids in porous media. This work is divided into three parts: development of numerical and analytical solutions; theoretical studies of transient flow of non-Newtonian fluids in porous media; and applications of well test analysis and displacement efficiency evaluation to field problems. A fully implicit, integral finite difference model has been developed for simulation of non-Newtonian and Newtonian fluid flow through porous media. Several commonly-used rheological models of power-law and Bingham plastic non-Newtonian fluids have been incorporated in the simulator. A Buckley-Leverett type analytical solution for one-dimensional, immiscible displacement involving non-Newtonian fluids in porous media has been developed. An integral method is also presented for the study of transient flow of Bingham fluids in porous media. In addition, two well test analysis methods have been developed for analyzing pressure transient tests of power-law and Bingham fluids, respectively. Applications are included to demonstrate this new technology. The physical mechanisms involved in immiscible displacement with non-Newtonian fluids in porous media have been studied using the Buckley-Leverett type analytical solution. In another study, an idealized fracture model has been used to obtain some insights into the flow of a power-law fluid in a double-porosity medium. Transient flow of a general pseudoplastic fluid has been studied numerically. 125 refs., 91 figs., 12 tabs.

  15. A Comprehensive Theoretical Investigation of the Molecular Properties of Methyl Bromide (CH3Br)

    NASA Astrophysics Data System (ADS)

    Yu, Ang-Yang; Efil, Kürşat; Yang, Rui; Hu, Qing-Miao

    2015-12-01

    The properties of the ground and the lowest excited state of methyl bromide (CH3Br) have been studied with and without inclusion of the solvent effects in this work. The geometric parameters, energies, and frequencies of the ground state and the triplet state are calculated by using the MP2(full)/6-311++G** level of theory. The vertical excitation for the singlet state is also investigated. It is found that the theoretical results performed by the TDDFT/B3P86/6-311++G** method are in the best agreement with the experimental results. In addition, the dissociation energy of CH3Br molecule is computed at MP2(full)/6-311++G** level of theory for the gas phase and in water. The ionisation potential (IP), electron affinity (EA), electronegativity (χ), electrophilicity index (ω), hardness (η), softness (S), and chemical potential (μ) values are calculated from HOMO-LUMO energies both in the gas phase and in solvent (water). These theoretical results could serve as a guide for future experimental investigations.

  16. Theoretical calculation (DFT), Raman and surface-enhanced Raman scattering (SERS) study of ponceau 4R

    NASA Astrophysics Data System (ADS)

    Xie, Yunfei; Li, Yan; Sun, Yingying; Wang, Heya; Qian, He; Yao, Weirong

    2012-10-01

    Ponceau 4R is used as a coloring agent in many different products, such as food, drinks, medicines, cosmetics and tobacco. However, ponceau 4R also shows carcinogenic, teratogenic and mutagenic behavior in high doses. In this work, standard Raman, theoretical Raman and surface-enhanced Raman scattering (SERS) spectra have been used to investigate ponceau 4R. More specifically, density functional theory (DFT) calculations have been used to calculate the optimized Raman spectrum of ponceau 4R at the B3LYP/6-31G(d) level. This has provided a better understanding of the optimized geometry and vibrational frequencies of this dye. In addition, the experimental spectrum of ponceau 4R has been compared with the theoretical spectrum; good agreement was obtained. Finally, it has shown that using SERS the detection limit of the ponceau 4R solution can be as low as 5 μg/mL. This has been achieved by SERS measurements of ponceau 4R on a substrate of gold nanoparticles. The SERS peaks at 1030, 1236, 1356 and 1502 cm-1 were chosen as index for semi-quantitative analysis, showing that the SERS technique provided a useful ultrasensitive method for the detection of ponceau 4R.

  17. The Alkaline Hydrolysis of Sulfonate Esters: Challenges in Interpreting Experimental and Theoretical Data

    PubMed Central

    2013-01-01

    Sulfonate ester hydrolysis has been the subject of recent debate, with experimental evidence interpreted in terms of both stepwise and concerted mechanisms. In particular, a recent study of the alkaline hydrolysis of a series of benzene arylsulfonates (Babtie et al., Org. Biomol. Chem.10, 2012, 8095) presented a nonlinear Brønsted plot, which was explained in terms of a change from a stepwise mechanism involving a pentavalent intermediate for poorer leaving groups to a fully concerted mechanism for good leaving groups and supported by a theoretical study. In the present work, we have performed a detailed computational study of the hydrolysis of these compounds and find no computational evidence for a thermodynamically stable intermediate for any of these compounds. Additionally, we have extended the experimental data to include pyridine-3-yl benzene sulfonate and its N-oxide and N-methylpyridinium derivatives. Inclusion of these compounds converts the Brønsted plot to a moderately scattered but linear correlation and gives a very good Hammett correlation. These data suggest a concerted pathway for this reaction that proceeds via an early transition state with little bond cleavage to the leaving group, highlighting the care that needs to be taken with the interpretation of experimental and especially theoretical data. PMID:24279349

  18. Theoretical prediction of vibrational spectra

    NASA Astrophysics Data System (ADS)

    Niu, Zefu; Dunn, Kevin M.; Boggs, James E.

    The complete harmonic force field and the diagonal and first off-diagonal cubic constants of aniline have been calculated ab initio using a 4-21 basis set augmented by addition of d functions to the nitrogen atom. The force constants were then scaled using scale factors optimized previously to give the best fit to the similarly computed vibrational spectra of benzene and its deuterated isotopomers. The vibrational spectra of aniline, aniline-NHD, and aniline-ND2 were then calculated from this scaled quantum mechanical (SQM) force field and compared with experimentally observed spectra. Several corrections were made to previously proposed empirical spectral assignments. Because of computational difficulties, no definitive statement can be made about the torsion or inversion modes of the amino group. Aside from these and the C-H stretching frequencies for which the detailed assignment is still quite uncertain, the average deviation between the observed frequencies and those obtained entirely from the scaled computed force field is 9·1 cm-1. Dipole moment derivatives and infrared absorption intensities were also calculated, but these are of lower accuracy.

  19. Theoretical nuclear physics. Final report

    SciTech Connect

    1997-05-01

    As the three-year period FY93-FY96 ended, there were six senior investigators on the grant full-time: Bulgac, Henley, Miller, Savage, van Kolck and Wilets. This represents an increase of two members from the previous three-year period, achieved with only a two percent increase over the budget for FY90-FY93. In addition, the permanent staff of the Institute for Nuclear Theory (George Bertsch, Wick Haxton, and David Kaplan) continued to be intimately associated with our physics research efforts. Aurel Bulgac joined the Group in September, 1993 as an assistant professor, with promotion requested by the Department and College of Arts and Sciences by September, 1997. Martin Savage, who was at Carnegie-Mellon University, jointed the Physics Department in September, 1996. U. van Kolck continued as research assistant professor, and we were supporting one postdoctoral research associate, Vesteinn Thorssen, who joined us in September, 1995. Seven graduate students were being supported by the Grant (Chuan-Tsung Chan, Michael Fosmire, William Hazelton, Jon Karakowski, Jeffrey Thompson, James Walden and Mitchell Watrous).

  20. Evaluation of certain food additives.

    PubMed

    2012-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to concluding as to safety concerns and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for five food additives (magnesium dihydrogen diphosphate; mineral oil (medium and low viscosity) classes II and III; 3-phytase from Aspergillus niger expressed in Aspergillus niger; serine protease (chymotrypsin) from Nocardiopsis prasina expressed in Bacillus licheniformis; and serine protease (trypsin) from Fusarium oxysporum expressed in Fusarium venenatum) and 16 groups of flavouring agents (aliphatic and aromatic amines and amides; aliphatic and aromatic ethers; aliphatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids and related esters, sulfides, disulfides and ethers containing furan substitution; aliphatic linear alpha,beta-unsaturated aldehydes, acids and related alcohols, acetals and esters; amino acids and related substances; epoxides; furfuryl alcohol and related substances; linear and branched-chain aliphatic, unsaturated, unconjugated alcohols, aldehydes, acids and related esters; miscellaneous nitrogen-containing substances; phenol and phenol derivatives; pyrazine derivatives; pyridine, pyrrole and quinoline derivatives; saturated aliphatic acyclic branched-chain primary alcohols, aldehydes and acids; simple aliphatic and aromatic sulfides and thiols; sulfur-containing heterocyclic compounds; and sulfur-substituted furan derivatives). Specifications for the following food additives were revised: ethyl cellulose, mineral oil (medium viscosity), modified starches and titanium

  1. Evaluation of certain food additives.

    PubMed

    2012-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to concluding as to safety concerns and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for five food additives (magnesium dihydrogen diphosphate; mineral oil (medium and low viscosity) classes II and III; 3-phytase from Aspergillus niger expressed in Aspergillus niger; serine protease (chymotrypsin) from Nocardiopsis prasina expressed in Bacillus licheniformis; and serine protease (trypsin) from Fusarium oxysporum expressed in Fusarium venenatum) and 16 groups of flavouring agents (aliphatic and aromatic amines and amides; aliphatic and aromatic ethers; aliphatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids and related esters, sulfides, disulfides and ethers containing furan substitution; aliphatic linear alpha,beta-unsaturated aldehydes, acids and related alcohols, acetals and esters; amino acids and related substances; epoxides; furfuryl alcohol and related substances; linear and branched-chain aliphatic, unsaturated, unconjugated alcohols, aldehydes, acids and related esters; miscellaneous nitrogen-containing substances; phenol and phenol derivatives; pyrazine derivatives; pyridine, pyrrole and quinoline derivatives; saturated aliphatic acyclic branched-chain primary alcohols, aldehydes and acids; simple aliphatic and aromatic sulfides and thiols; sulfur-containing heterocyclic compounds; and sulfur-substituted furan derivatives). Specifications for the following food additives were revised: ethyl cellulose, mineral oil (medium viscosity), modified starches and titanium

  2. Theoretical study on the structural and antioxidant properties of some recently synthesised 2,4,5-trimethoxy chalcones.

    PubMed

    Wang, Guirong; Xue, Yunsheng; An, Lin; Zheng, Youguang; Dou, Yunyan; Zhang, Ling; Liu, Yi

    2015-03-15

    The free radical scavenging activity of a series of 2,4,5-trimethoxy chalcones has been computationally explored using the density functional theory (DFT) method. Three potential working mechanisms, hydrogen atom transfer (HAT), stepwise electron transfer proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET) have been investigated. The physiochemical parameters including O-H bond dissociation enthalpy (BDE), ionisation potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA) and electron transfer enthalpy (ETE) have been calculated in gas phase and solvents. The order of antioxidant efficiencies predicted theoretically in this work is in good agreement with that reported by experimental results. The results obtained demonstrate that HAT would be the most favourable mechanism in the gas and benzene phases, whereas the SPLET mechanism is the thermodynamically preferred pathway in polar media. In addition, the importance of the A-ring on the radical scavenging capabilities of chalcones was also confirmed.

  3. A practical and theoretical definition of very small field size for radiotherapy output factor measurements

    SciTech Connect

    Charles, P. H. Crowe, S. B.; Langton, C. M.; Trapp, J. V.; Cranmer-Sargison, G.; Thwaites, D. I.; Kairn, T.; Knight, R. T.; Kenny, J.

    2014-04-15

    Purpose: This work introduces the concept of very small field size. Output factor (OPF) measurements at these field sizes require extremely careful experimental methodology including the measurement of dosimetric field size at the same time as each OPF measurement. Two quantifiable scientific definitions of the threshold of very small field size are presented. Methods: A practical definition was established by quantifying the effect that a 1 mm error in field size or detector position had on OPFs and setting acceptable uncertainties on OPF at 1%. Alternatively, for a theoretical definition of very small field size, the OPFs were separated into additional factors to investigate the specific effects of lateral electronic disequilibrium, photon scatter in the phantom, and source occlusion. The dominant effect was established and formed the basis of a theoretical definition of very small fields. Each factor was obtained using Monte Carlo simulations of a Varian iX linear accelerator for various square field sizes of side length from 4 to 100 mm, using a nominal photon energy of 6 MV. Results: According to the practical definition established in this project, field sizes ≤15 mm were considered to be very small for 6 MV beams for maximal field size uncertainties of 1 mm. If the acceptable uncertainty in the OPF was increased from 1.0% to 2.0%, or field size uncertainties are 0.5 mm, field sizes ≤12 mm were considered to be very small. Lateral electronic disequilibrium in the phantom was the dominant cause of change in OPF at very small field sizes. Thus the theoretical definition of very small field size coincided to the field size at which lateral electronic disequilibrium clearly caused a greater change in OPF than any other effects. This was found to occur at field sizes ≤12 mm. Source occlusion also caused a large change in OPF for field sizes ≤8 mm. Based on the results of this study, field sizes ≤12 mm were considered to be theoretically very small for 6

  4. Polymer-additive extraction via pressurized fluids and organic solvents of variously cross-linked poly(methylmethacrylates).

    PubMed

    Nazem, N; Taylor, L T

    2002-04-01

    Variously cross-linked poly(methylmethacrylates) (PMMAs) are synthesized with three additives incorporated at theoretically 1000 microg of the additive per gram of prepared polymer. The additives are Irganox 1010, Irganox 1076, and Irgafos 168. The in-house" synthesized polyacrylates are then subjected to supercritical fluid extraction (SFE) to determine if additive recovery is a function of percent cross-linking. Although considerable work in this regard has been performed with non-cross-linked polyolefins, the literature is lacking regarding polyacrylates. Some additive degradation apparently occurs during the synthesis, as judged by the increased complexity of the extract high-performance liquid chromatographic trace and the low percent recoveries observed especially for the Irganoxes. For low polymer cross-linking (1%), it appears that both PMMA synthetic reproducibility and readily observed polymer swelling during SFE are serious issues that adversely affect additive percent recovery and precision of results. Higher percent cross-linking yields more consistent analytical data than low percent cross-linking, even though the amount of additive extracted in all PMMA samples (regardless of cross-linking percentage) is essentially the same whether the extraction is via SFE or liquid-solid extraction with methylene chloride. Results for comparably cross-linked poly(ethylmethacrylate) and poly(butylmethacrylate) are similar to PMMA.

  5. The addition of disilanes to cumulenes

    SciTech Connect

    Chen, Y.

    1997-10-08

    The syntheses of silicon-containing compounds and the studies of their rearrangements have been active research areas in the Barton research group. Previously, the addition of disilanes to acetylenes was studied in the group and an intramolecular 2S + 2A mechanism has been proposed. In this thesis, the work is focused on the addition of disilanes to cumulenes. The syntheses of the precursors are discussed and the possible mechanisms for their thermal, photochemical and catalytic rearrangements are proposed. Conjugated organic polymers have been studied in the group since 1985 because of their potential for exhibiting high electroconductivity, photoconductivity, strong non-linear optical response and intense fluorescence. In the second section of this dissertation, the synthesis and property studies of poly(phenylene vinylene) analogues are discussed.

  6. Facilities removal working group

    SciTech Connect

    1997-03-01

    This working group`s first objective is to identify major economic, technical, and regulatory constraints on operator practices and decisions relevant to offshore facilities removal. Then, the group will try to make recommendations as to regulatory and policy adjustments, additional research, or process improvements and/or technological advances, that may be needed to improve the efficiency and effectiveness of the removal process. The working group will focus primarily on issues dealing with Gulf of Mexico platform abandonments. In order to make the working group sessions as productive as possible, the Facilities Removal Working Group will focus on three topics that address a majority of the concerns and/or constraints relevant to facilities removal. The three areas are: (1) Explosive Severing and its Impact on Marine Life, (2) Pile and Conductor Severing, and (3) Deep Water Abandonments This paper will outline the current state of practice in the offshore industry, identifying current regulations and specific issues encountered when addressing each of the three main topics above. The intent of the paper is to highlight potential issues for panel discussion, not to provide a detailed review of all data relevant to the topic. Before each panel discussion, key speakers will review data and information to facilitate development and discussion of the main issues of each topic. Please refer to the attached agenda for the workshop format, key speakers, presentation topics, and panel participants. The goal of the panel discussions is to identify key issues for each of the three topics above. The working group will also make recommendations on how to proceed on these key issues.

  7. Density functional reactivity theory study of SN2 reactions from the information-theoretic perspective.

    PubMed

    Wu, Zemin; Rong, Chunying; Lu, Tian; Ayers, Paul W; Liu, Shubin

    2015-10-28

    As a continuation of our recent efforts to quantify chemical reactivity with quantities from the information-theoretic approach within the framework of density functional reactivity theory, the effectiveness of applying these quantities to quantify electrophilicity for the bimolecular nucleophilic substitution (SN2) reactions in both gas phase and aqueous solvent is presented in this work. We examined a total of 21 self-exchange SN2 reactions for the compound with the general chemical formula of R1R2R3C-F, where R1, R2, and R3 represent substituting alkyl groups such as -H, -CH3, -C2H5, -C3H7, and -C4H9 in both gas and solvent phases. Our findings confirm that scaling properties for information-theoretic quantities found elsewhere are still valid. It has also been verified that the barrier height has the strongest correlation with the electrostatic interaction, but the contributions from the exchange-correlation and steric effects, though less significant, are indispensable. We additionally unveiled that the barrier height of these SN2 reactions can reliably be predicted not only by the Hirshfeld charge and information gain at the regioselective carbon atom, as previously reported by us for other systems, but also by other information-theoretic descriptors such as Shannon entropy, Fisher information, and Ghosh-Berkowitz-Parr entropy on the same atom. These new findings provide further insights for the better understanding of the factors impacting the chemical reactivity of this vastly important category of chemical transformations.

  8. The Work Values of Japanese Women.

    ERIC Educational Resources Information Center

    Engel, John W.

    Empirical studies of Japanese work ethics have tended to focus on male workers while neglecting women. In addition, work values in both Japan and the United States appear to be changing. More information is needed on the work values of American and Japanese female workers. A study was conducted to explore the work ethics of Japanese women and to…

  9. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  10. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  11. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  12. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  13. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  14. Decontamination formulation with sorbent additive

    DOEpatents

    Tucker; Mark D. , Comstock; Robert H.

    2007-10-16

    A decontamination formulation and method of making that neutralizes the adverse health effects of both chemical and biological compounds, especially chemical warfare (CW) and biological warfare (BW) agents, and toxic industrial chemicals. The formulation provides solubilizing compounds that serve to effectively render the chemical and biological compounds, particularly CW and BW compounds, susceptible to attack, and at least one reactive compound that serves to attack (and detoxify or kill) the compound. The formulation includes at least one solubilizing agent, a reactive compound, a bleaching activator, a sorbent additive, and water. The highly adsorbent, water-soluble sorbent additive (e.g., sorbitol or mannitol) is used to "dry out" one or more liquid ingredients, such as the liquid bleaching activator (e.g., propylene glycol diacetate or glycerol diacetate) and convert the activator into a dry, free-flowing powder that has an extended shelf life, and is more convenient to handle and mix in the field.

  15. Additive-free digital microfluidics.

    PubMed

    Freire, Sergio L S; Tanner, Brendan

    2013-07-16

    Digital microfluidics, a technique for manipulation of droplets, is becoming increasingly important for the development of miniaturized platforms for laboratory processes. Despite the enthusiasm, droplet motion is frequently hindered by the desorption of proteins or other analytes to surfaces. Current approaches to minimize this unwanted surface fouling involve the addition of extra species to the droplet or its surroundings, which might be problematic depending on the droplet content. Here, a new strategy is introduced to move droplets containing cells and other analytes on solid substrates, without extra moieties; in particular, droplets with bovine serum albumin could be moved at a concentration 2000 times higher than previously reported (without additives). This capability is achieved by using a soot-based superamphiphobic surface combined with a new device geometry, which favors droplet rolling. Contrasting with electrowetting, wetting forces are not required for droplet motion.

  16. A mechanistic study of the addition of alcohol to a five-membered ring silene via a photochemical reaction.

    PubMed

    Su, Ming-Der

    2016-03-21

    The mechanism for the photochemical rearrangement of a cyclic divinyldisilane (1-Si) in its first excited state ((1)π → (1)π*) is determined using the CAS/6-311G(d) and MP2-CAS/6-311++G(3df,3pd) levels of theory. The photoproduct, a cyclic silene, reacts with various alcohols to yield a mixture of cis- and trans- adducts. The two reaction pathways are denoted as the cis- addition path (path A) and the trans-addition path (path B). These model studies demonstrate that conical intersections play a crucial role in the photo-rearrangements of cyclic divinyldisilanes. The theoretical evidence also demonstrates that the addition of alcohol to a cyclic divinyldisilane follows the reaction path: cyclic divinyldisilane → Franck-Condon region → conical intersection → photoproduct (cyclic silene) → local intermediate (with alcohol) → transition state → cis- or trans-adduct. The theoretical studies demonstrate that the steric effects as well as the concentrations of CH3OH must have a dominant role in determining the yields of the final adducts by stereochemistry. The same mechanism for the carbon derivative (1-C) is also considered in this work. However, the theoretical results indicate that 1-C does not undergo a methanol addition reaction via the photochemical reaction pathway, since its energy of conical intersection (S1/S0-CI-C) is more than that of its FC (FC-C). The reason for these phenomena could be that the atomic radius of carbon is much smaller than that of silicon (77 and 117 pm, respectively). As a result, the conformation for 1-C is more sterically congested than that for 1-Si, along the 1,3-silyl-migration pathway. PMID:26928893

  17. Additive concentrates for distillate fuels

    SciTech Connect

    Rossi, A.; Lewtas, K.

    1985-08-27

    An additive concentrate for incorporation into wax containing petroleum fuel oil compositions to improve low temperature flow properties comprising an oil solution containing: 3% to 90 wt. % of a C30-C300 oil-soluble nitrogen compound wax crystal growth inhibitor having at least one straight C8-C40 alkyl chain and partial esters, and at least one mole per mole of an organic acid capable of hydrogen bonding to improve the solubility in the oil.

  18. [Creative works of the mentally ill as a problem for art (author's transl)].

    PubMed

    Loddenkemper, H

    1979-02-01

    The article "Creative Works of the Mentally Ill as a Problem for Art" attempts to analyse this complex field from a more art-theoretical viewpoint. In addition to the difficulties involved in identifying the causing factors of schizophrenia there is the problem of not having a uniform definition of art. Wölfli's example substantiates the evidence that the artistic works of the mentally ill display the same characteristics as far as creativity is concerned as those of mentally healthy artists and hence there is no reason for disqualifying their works. Some artists who had already achieved general recognition did not lose it after becoming afflicted with mental illness later in their lives. Does this mean that recognition depends on social status and not on the work itself?

  19. Theoretical study of inhomogenous fluids

    NASA Astrophysics Data System (ADS)

    Noworyta, Jerzy Piotr

    1998-07-01

    Binary, additive mixtures of hard spheres near the structureless 'hard' walls are studied with the grand canonical Monte Carlo (MC) simulation method. Binary mixtures of hard spheres and hard sphere systems in the neighborhood of hard walls had been studied separately before. This research for the first time incorporates both elements. A brief survey of the alternative methods that can be applied to study inhomogenous fluid systems is presented, with special attention paid to the integral equation theory. Well-known formulas utilizing the idea of a radial distribution function and a direct correlation function to describe the thermodynamics of the uniform hard sphere fluid through the solution of the Ornstein- Zernike (OZ) integral equation within the Percus-Yevick (PY) closure are given, as well as their generalization to the mixtures. Also presented are the empirical expressions (BMCSL), based on the PY and the scaled particle theory (SPT). The main features of the model assumed for the purpose of this study are hard spheres of two sizes, the conditions of the grand canonical ensemble and the existence of two parallel flat and structureless walls. In contrast to some recently published results, chemical potential is held constant for both species. Some details of the application of the classical Monte Carlo method to the investigated model are presented, including the procedure to ensure an unbiased Markov chain of states. The results of the simulation are analyzed with special attention to the choice of the equilibration point and the extrapolation of the density to the contact separation from the wall. The standard deviation is estimated through the block average method. Results are presented for the mixtures of hard spheres with a 3:5 and 1:3 diameter ratio. The applied range of chemical potentials allowed the simulation of moderately high densities, below the packing fraction of 0.4. Generally, the plots of the obtained reduced density profiles show good

  20. Additive manufacturing of hybrid circuits

    DOE PAGES

    Bell, Nelson S.; Sarobol, Pylin; Cook, Adam; Clem, Paul G.; Keicher, David M.; Hirschfeld, Deidre; Hall, Aaron Christopher

    2016-03-26

    There is a rising interest in developing functional electronics using additively manufactured components. Considerations in materials selection and pathways to forming hybrid circuits and devices must demonstrate useful electronic function; must enable integration; and must complement the complex shape, low cost, high volume, and high functionality of structural but generally electronically passive additively manufactured components. This article reviews several emerging technologies being used in industry and research/development to provide integration advantages of fabricating multilayer hybrid circuits or devices. First, we review a maskless, noncontact, direct write (DW) technology that excels in the deposition of metallic colloid inks for electrical interconnects.more » Second, we review a complementary technology, aerosol deposition (AD), which excels in the deposition of metallic and ceramic powder as consolidated, thick conformal coatings and is additionally patternable through masking. As a result, we show examples of hybrid circuits/devices integrated beyond 2-D planes, using combinations of DW or AD processes and conventional, established processes.« less

  1. Theoretical span loading and moments of tapered wings produced by aileron deflection

    NASA Technical Reports Server (NTRS)

    Pearson, H A

    1937-01-01

    The effect of tapered ailerons on linearly tapered wings is theoretically determined. Four different aileron spans are considered for each of three wing aspect ratios and each of four wing taper ratios. The change in lift on one half of the wing, the rolling moment, the additional induced drag, and the yawing moment, due to aileron deflection, are represented by non dimensional coefficients. Similar coefficients are given for the damping and yawing moments, the additional drag, and the change in lift, due to rolling. It was found possible to effect a fairly close agreement between the theoretical and experimental rolling moments by introducing into the theoretical expression for the rolling moment an effective change in angle of attack obtained from an analysis of flap data. The theoretical curves show that the highly tapered wing with long ailerons has a lower ratio of yawing to rolling moment and a lower additional induced drag than wings with less taper.

  2. Evaluation of certain food additives.

    PubMed

    2009-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to recommending acceptable daily intakes (ADIs) and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation and assessment of intake of food additives (in particular, flavouring agents). A summary follows of the Committee's evaluations of technical, toxicological and intake data for certain food additives (asparaginase from Aspergillus niger expressed in A. niger, calcium lignosulfonate (40-65), ethyl lauroyl arginate, paprika extract, phospholipase C expressed in Pichia pastoris, phytosterols, phytostanols and their esters, polydimethylsiloxane, steviol glycosides and sulfites [assessment of dietary exposure]) and 10 groups of related flavouring agents (aliphatic branched-chain saturated and unsaturated alcohols, aldehydes, acids and related esters; aliphatic linear alpha,beta-unsaturated aldehydes, acids and related alcohols, acetals and esters; aliphatic secondary alcohols, ketones and related esters; alkoxy-substituted allylbenzenes present in foods and essential oils and used as flavouring agents; esters of aliphatic acyclic primary alcohols with aliphatic linear saturated carboxylic acids; furan-substituted aliphatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids and related esters, sulfides, disulfides and ethers; miscellaneous nitrogen-containing substances; monocyclic and bicyclic secondary alcohols, ketones and related esters; hydroxy- and alkoxy-substituted benzyl derivatives; and substances structurally related to menthol). Specifications for the following food additives were revised: canthaxanthin; carob bean gum and carob bean gum (clarified); chlorophyllin copper complexes, sodium and potassium salts; Fast Green FCF; guar gum and guar gum (clarified

  3. Fire-Retardant Polymeric Additives

    NASA Technical Reports Server (NTRS)

    Williams, Martha K.; Smith, Trent M.

    2011-01-01

    Polyhydroxyamide (PHA) and polymethoxyamide (PMeOA) are fire-retardant (FR) thermoplastic polymers and have been found to be useful as an additive for imparting fire retardant properties to other compatible, thermoplastic polymers (including some elastomers). Examples of compatible flammable polymers include nylons, polyesters, and acrylics. Unlike most prior additives, PHA and PMeOA do not appreciably degrade the mechanical properties of the matrix polymer; indeed, in some cases, mechanical properties are enhanced. Also, unlike some prior additives, PHA and PMeOA do not decompose into large amounts of corrosive or toxic compounds during combustion and can be processed at elevated temperatures. PMeOA derivative formulations were synthesized and used as an FR additive in the fabrication of polyamide (PA) and polystyrene (PS) composites with notable reduction (>30 percent for PS) in peak heat release rates compared to the neat polymer as measured by a Cone Calorimeter (ASTM E1354). Synergistic effects were noted with nanosilica composites. These nanosilica composites had more than 50-percent reduction in peak heat release rates. In a typical application, a flammable thermoplastic, thermoplastic blend, or elastomer that one seeks to render flame-retardant is first dry-mixed with PHA or PMeOA or derivative thereof. The proportion of PHA or PMeOA or derivative in the mixture is typically chosen to lie between 1 and 20 weight percent. The dry blend can then be melt-extruded. The extruded polymer blend can further be extruded and/or molded into fibers, pipes, or any other of a variety of objects that may be required to be fire-retardant. The physical and chemical mechanisms which impart flame retardancy of the additive include inhibiting free-radical oxidation in the vapor phase, preventing vaporization of fuel (the polymer), and cooling through the formation of chemical bonds in either the vapor or the condensed phase. Under thermal stress, the cyclic hydroxyl/ methoxy

  4. Sexual systems and life history of barnacles: a theoretical perspective.

    PubMed

    Yamaguchi, Sachi; Charnov, Eric L; Sawada, Kota; Yusa, Yoichi

    2012-09-01

    Thoracican barnacles show one of the most diverse sexual systems in animals: hermaphroditism, dioecy (males and females), and androdioecy (males and hermaphrodites). In addition, when present, male barnacles are very small and are called "dwarf males". The diverse sexual systems and male dwarfism in this taxon have attracted both theoretical and empirical biologists. In this article, we review the theoretical studies on barnacles' sexual systems in the context of sex allocation and life history theories. We first introduce the sex allocation models by Charnov, especially in relation to the mating group size, and a new expansion of his models is also proposed. We then explain three studies by Yamaguchi et al., who have studied the interaction between sex allocation and life history in barnacles. These studies consistently showed that limited mating opportunity favors androdioecy and dioecy over hermaphroditism. In addition, other factors, such as rates of survival and availability of food, are also important. We discuss the importance of empirical studies testing these predictions and how empirical studies interact with theoretical constructs.

  5. Surety theoretics: The forest or the trees?

    SciTech Connect

    Senglaub, M.

    1997-10-30

    Periodically one needs to re-examine the objectives and the efforts associated with a field of study. In the case of surety which comprises, safety, security and reliability one needs to be sure that theoretical efforts support the needs of systems and design engineers in satisfying stakeholder requirements. The current focus in the surety areas does not appear to address the theoretical foundations needed by the systems engineer. Examination of papers and abstracts demonstrate significant effort along the lines of thermal hydraulics, chemistry, structural response, control theory, etc. which are analytical disciplines which provide support for a surety theoretic but do not constitute a theoretic. The representations currently employed, fault trees etc., define static representations of a system, not the dynamic representation characteristic of response in abnormal, hostile or under degrading conditions. Current methodologies would require a semi-infinite set of scenarios to be examined before a system could be certified as satisfying a surety requirement. The elements that are required of a surety theoretic must include: (1) a dynamic representation of the system; (2) the ability to automatically identify terminal states of the system; and (3) determine the probabilities of specified terminal states under dynamic conditions. This paper examines the requirements of a surety theoretic that will support the efforts of the design and development engineer. Speculations then follow on technologies that might provide the theoretical and support foundations needed by the systems engineering community to form a robust surety analysis and design environment.

  6. Working group 1: Coronal streamers

    SciTech Connect

    Kopp, R.A.

    1994-04-01

    The working group on colonel streamers convened on the first day of the 2nd SOHO Workshop, which took place in Marciana Marina, Isola d`Elba, 27 September--1 October 1993. Recent progress in streamer observational techniques and theoretical modeling was reported. The contribution of streamers to the mass and energy supply for the solar wind was discussed. Moreover, the importance of thin electric current sheets for determining both the gross dynamical properties of streamers and the fine-scale filamentary structure within streamers, was strongly emphasized. Potential advances to our understanding of these areas of colonel physics that could be made by the contingent of instruments aboard SOHO were pointed out.

  7. Surface tension increment due to solute addition

    NASA Astrophysics Data System (ADS)

    Hsin, Wei Lun; Sheng, Yu-Jane; Lin, Shi-Yow; Tsao, Heng-Kwong

    2004-03-01

    Addition of solute into solvent may lead to an increase in surface tension, such as salt in water and water in alcohol, due to solute depletion at the interface. The repulsion of the solute from the interface may originate from electrostatic forces or solute-solvent attraction. On the basis of the square-well model for the interface-solute interaction, we derive the surface tension increment Δγ by both canonical and grand-canonical routes (Gibbs adsorption isotherm) for a spherical droplet. The surface tension is increased linearly with the bulk concentration of the solute cb and the interaction range λ. The theoretical results are consistent with those obtained by experiments and Monte Carlo simulations up to a few molarity. For weak repulsion, the increment is internal energy driven. When the repulsion is large enough, the surface tension increment is entropy driven and approaches the asymptotic limit, Δγ≃cbkBTλ, due to the nearly complete depletion of the solute at the interface. Our result may shed some light on the surface tension increment for electrolyte solutions with concentration above 0.2M.

  8. The Role of Working Memory in Multimedia Instruction: Is Working Memory Working during Learning from Text and Pictures?

    ERIC Educational Resources Information Center

    Schuler, Anne; Scheiter, Katharina; van Genuchten, Erlijn

    2011-01-01

    A lot of research has focused on the beneficial effects of using multimedia, that is, text and pictures, for learning. Theories of multimedia learning are based on Baddeley's working memory model (Baddeley 1999). Despite this theoretical foundation, there is only little research that aims at empirically testing whether and more importantly how…

  9. Theoretical model of infrared radiation of dressed human body indoors

    NASA Astrophysics Data System (ADS)

    Xiong, Zonglong; Yang, Kuntao

    2008-02-01

    The human body detecting by infrared thermography plays an important role in the field of medical treatment, scout and rescuing work after disaster occuring. The infrared image theoretical model is a foundation for a human body detecting because it can improve the ability and efficiency. The essence and significance of the information on the temperature field of the human body in indoor environment is systematically discussed on the basis of physical structure and thermoregulation system. The various factors that influence the body temperature are analyzed, then the method for the calculation of temperature distribution of the surface temperature is introduced. On the basis of the infrared radiation theory, a theoretical model is proposed to calculate the radiant flux intensity of the human body. This model can be applied to many fields.

  10. Silicene: a review of recent experimental and theoretical investigations.

    PubMed

    Houssa, M; Dimoulas, A; Molle, A

    2015-07-01

    Silicene is the silicon counterpart of graphene, i.e. it consists in a single layer of Si atoms with a hexagonal arrangement. We present a review of recent theoretical and experimental works on this novel two dimensional material. We discuss first the structural, electronic and vibrational properties of free-standing silicene, as predicted from first-principles calculations. We next review theoretical studies on the interaction of silicene with different substrates. The growth and experimental characterization of silicene on Ag(1 1 1) is next discussed, providing insights into the different phases or atomic arrangements of silicene observed on this metallic surface, as well as on its electronic structure. Recent experimental findings about the likely formation of hexagonal Si nanosheets on MoS2 are also highlighted.

  11. Metal Additive Manufacturing: A Review

    NASA Astrophysics Data System (ADS)

    Frazier, William E.

    2014-06-01

    This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.

  12. Individualized additional instruction for calculus

    NASA Astrophysics Data System (ADS)

    Takata, Ken

    2010-10-01

    College students enrolling in the calculus sequence have a wide variance in their preparation and abilities, yet they are usually taught from the same lecture. We describe another pedagogical model of Individualized Additional Instruction (IAI) that assesses each student frequently and prescribes further instruction and homework based on the student's performance. Our study compares two calculus classes, one taught with mandatory remedial IAI and the other without. The class with mandatory remedial IAI did significantly better on comprehensive multiple-choice exams, participated more frequently in classroom discussion and showed greater interest in theorem-proving and other advanced topics.

  13. The Mozart Effect: Additional Data.

    PubMed

    Hughes, John R.

    2002-04-01

    After the review of the Mozart effect was published in this journal (Hughes JR. Epilepsy Behav 2001;2:369-417), additional data from the music of Haydn and Liszt have been analyzed that may account for the decrease in seizure activity originally reported during Mozart music. Even with these added data Mozart music continued to score significantly higher than the selections from the other six composers in one of the important characteristics of this music, namely, the repetition of the melody. However Haydn's values were second highest among Mozart, J. S. Bach, Wagner, Beethoven, Chopin, and Liszt.

  14. A Generalized Information Theoretical Model for Quantum Secret Sharing

    NASA Astrophysics Data System (ADS)

    Bai, Chen-Ming; Li, Zhi-Hui; Xu, Ting-Ting; Li, Yong-Ming

    2016-07-01

    An information theoretical model for quantum secret sharing was introduced by H. Imai et al. (Quantum Inf. Comput. 5(1), 69-80 2005), which was analyzed by quantum information theory. In this paper, we analyze this information theoretical model using the properties of the quantum access structure. By the analysis we propose a generalized model definition for the quantum secret sharing schemes. In our model, there are more quantum access structures which can be realized by our generalized quantum secret sharing schemes than those of the previous one. In addition, we also analyse two kinds of important quantum access structures to illustrate the existence and rationality for the generalized quantum secret sharing schemes and consider the security of the scheme by simple examples.

  15. Additive manufacturing of RF absorbers

    NASA Astrophysics Data System (ADS)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  16. Fuel Additives: Canada bans MMT

    SciTech Connect

    Sissell, K.

    1997-04-16

    The Canadian Senate voted late last week to ban use of the manganese-based fuel additive MMT, produced only in the US by Ethyl. MMT, which has been sold in Canada for the past 20 years and accounts for about half of Ethyl`s Canadian sales, has been criticized by environmentalists, who have raised public health concerns, and automakers, who say it harms emission control systems. {open_quotes}Canada`s vote is a great victory for public health and the environment,{close_quotes} says Environmental Defense Fund executive director Fred Krupp. {open_quotes}The US should move swiftly to follow suit and suspend sales of MMT until adequate toxicity testing on the additive is completed.{close_quotes} EPA had refused to approve MMT for sale because of health concerns but was compelled to do so by a December 1995 court ruling. Ethyl asserts the ban violates Canada`s obligations under Nafta and says it will file a damage claim with the Nafta arbitration panel.

  17. Eighteenth annual West Coast theoretical chemistry conference

    SciTech Connect

    1997-05-01

    Abstracts are presented from the eighteenth annual west coast theoretical chemistry conference. Topics include molecular simulations; quasiclassical simulations of reactions; photodissociation reactions; molecular dynamics;interface studies; electronic structure; and semiclassical methods of reactive systems.

  18. A theoretical approach to measuring pilot workload

    NASA Technical Reports Server (NTRS)

    Kantowitz, B. H.

    1984-01-01

    Theoretical assumptions used by researchers in the area of attention, with emphasis upon errors and inconsistent assumptions used by some researchers were studied. Two GAT experiments, two laboratory studies and one field experiment were conducted.

  19. Reconceptualizing Working Memory in Educational Research

    ERIC Educational Resources Information Center

    Fenesi, Barbara; Sana, Faria; Kim, Joseph A.; Shore, David I.

    2015-01-01

    In recent years, research from cognitive science has provided a solid theoretical framework to develop evidence-based interventions in education. In particular, research into reading, writing, language, mathematics and multimedia learning has been guided by the application of Baddeley's multicomponent model of working memory. However, an…

  20. Work Values System Development during Adolescence

    ERIC Educational Resources Information Center

    Porfeli, Erik J.

    2007-01-01

    Work values stability, change, and development can be appreciably reduced to a living system model [Ford, D. H. (1994). "Humans as self-constructing living systems: A developmental perspective on behavior and personality" (2nd ed.). Hillsdale, NJ: Lawrence Erlbaum Associates]. This theoretical model includes discrepancy-reducing and…