The evolution of in-plane magnetic anisotropy in CoFeB/GaAs(001) films annealed at different temperatures

NASA Astrophysics Data System (ADS)

Tu, Hongqing; Wang, Ji; Wei, Lujun; Yuan, Yuan; Zhang, W.; You, Biao; Du, Jun

2018-05-01

A considerable in-plane uniaxial magnetic anisotropy (UMA) field (Hu ˜ 300 Oe) could be achieved when the amorphous CoFeB film was deposited on the GaAs(001) wafer by magnetron-sputtering after proper etch-annealed procedure. In order to get deep insights into the mechanism of the UMA, the film was annealed at different temperatures and the evolution of the in-plane magnetic anisotropy was investigated carefully. With increasing the annealing temperature (TA), the UMA could be maintained well when TA reached 250°C, but became very weak at 300°C. However, when TA was elevated to 400°C, another UMA (Hu ˜ 130 Oe) was built accompanied with a fourfold magnetic anisotropy with its strength of about 50 Oe. In terms of the magnetic anisotropy evolution along with TA, the anelastic strain, which is thought to be resulted from the interfacial interaction between CoFeB and GaAs, may play a dominant role in producing the enhanced UMA based on the `bond-orientational' anisotropy (BOA) model.

"Conical Hut": A Basic Form of House Types in Timor Island

NASA Astrophysics Data System (ADS)

Chen, Y. R.; Lim, Y. L.; Wang, M. H.; Chen, C. Y.

2015-08-01

Timor Island situates in the southeast end of Southeast Asia. The island accommodates many ethnic groups, which produce many diverse house types. As visiting East Timor in 2012 and Timor Island in 2014, we found the "Pair- House Type" widely spread over Timor Island. Uma Lulik (holy house), accommodating the ancestry soul, fireplace and elder's bed, and Uma Tidor (house for sleep), containing living, sleeping and working space, compose the pair-house. The research team visited 14 ethnic groups and their houses, some of which were measured and drawn into 3D models as back to Taiwan. Uma Tidors of each ethnic group are quite similar with rectangular volume and hip roof, however, one of the fourteen ethnic groups can build cylinder houses for Uma Tidor. Uma Luliks of different ethnic groups are diversified and special. One group of the Uma Luliks shows a rectangular or square volume sheltered by a hip roof. The other group of Uma Luliks presents a non-specific volume under a conical roof, that we called the "conical hut". Seven ethnic groups, Atoni, Weimua, Makassae, Mambai, Bunaq, Kemak and Bekais, have built "conical huts" for the use of Uma Lulik. People of the seven ethnic groups can construct a reasonable structural system to support the conical roof, and take good advantage of the space under the conical roof to meet their sacred needs and everyday life. "Conical Hut" may be regarded as the basic form of the house types adopted by the seven ethnic groups. It contains the basic spatial limits and the formal properties that the construction systems have to follow. Based on the concise rules of the basic form, people of each ethnic group use their talents, skills and building materials to generate variations of "conical hut", which are different in house scale, spatial layout, construction system and form. The "conical huts" contain the consistency that all the huts come from the basic form, meanwhile, they also present the diversification that each conical hut has differed. "Consistent but diversified", is one of the most interesting issues in typological study that we can observe in Timorese houses.

Ondas de choque em jatos de quasares e objetos BL Lacertae

NASA Astrophysics Data System (ADS)

Melo, F. E.; Botti, L. C. L.

2003-08-01

Este trabalho é parte de um projeto que vem sendo realizado há dois anos no CRAAM, cujos objetivos principais são analisar e aplicar um modelo generalizado de ondas de choque em jatos relativísticos de plasma, presentes em quasares e objetos BL Lacertae, para explicar a variabilidade observada nestes objetos. O método consiste em uma decomposição de curvas de luz em séries de explosões similares, em várias freqüências, baseando-se em uma evolução espectro-temporal média das explosões. A partir da evolução média, um ajuste de cada explosão é feito com base em equações empíricas, modificando-se apenas parâmetros específicos de cada explosão. Inicialmente o modelo foi aplicado ajustando-se as curvas de luz a explosões delineadas por uma evolução do choque em três estágios, segundo a predominância do processo de emissão: síncrotron, Compton e adiabático. Entretanto, nesta nova fase de projeto, visando uma parametrização mais concisa, uma otimização do algoritmo de ajuste e uma convergência mais rápida, a formulação para cada evento foi assumida com uma evolução em apenas dois estágios: subida e descida. Isto possibilitou uma ótima delineação das curvas de luz das fontes OV236, OJ287, 3C273 e BL Lac, entre 1980 e 2000, nas freqüências 4.8, 8.0, 14.5 e 22 GHz, utilizando-se dados do Observatório da Universidade de Michigan, do Observatório do Itapetinga (Atibaia SP) e do Observatório Metsähovi. Como conclusões importantes, verificou-se que: os parâmetros ajustados descrevem o comportamento do jato; os valores do índice que descreve a expansão do jato sugerem que o mesmo se expande de uma forma não-cônica; o campo magnético é turbulento atrás da frente de choque; e as peculiaridades das explosões são devidas à influência de grandezas tais como o coeficiente da distribuição espectral de energia dos elétrons, a intensidade de campo magnético e o fator de feixe Doppler, no início do choque.

Ultraviolet studies of nova-like variables with the IUE

NASA Technical Reports Server (NTRS)

Guinan, E. F.

1983-01-01

KQ Mon is a new UX UMa-type nova-like variable. Optical spectra taken in 1978 reveal very shallow Balmer absorption lines and He I (wavelength 4471) absorption. There was no evidence of orbital variations but the appearance of the optical spectrum and the presence of low amplitude flickering suggested a strong similarity to CD-42 degrees 14462 (=V3885 Sgr) and other members of the UX UMa class. KQ Mon was observed at low dispersion with the IUE satellite. Six spectra taken with the short wavelength prime (SWP) camera are dominated by strong broad absorption lines due to N V, O I, Si III, Si IV, C IV, He II, N IV, and A1 III. There is little evidence of orbital phase modulation over the time baseline of the observations. Unlike UV observations of other UX UMa-type objects, KQ Mon exhibits no emission lines or P Cygni-type profiles and the velocity displacements appear to be smaller, suggesting the absence of a hot, high velocity wind characterizing other UX UMa stars. The relationship of KQ Mon to other UX UMa disk stars is discussed and a model is suggested to explain their observed properties and the lack of major outbursts.

FUSE Observations of the Bright, Eclipsing Nova-like Cataclysmic Variable, UX UMa (FUSE 2000)

NASA Technical Reports Server (NTRS)

Long, Knox; Froning, Cynthia

2004-01-01

This was a project to study the disk and wind of the eclipsing nova-like variable UX UMa, in order to better define the wind geometry of the system, including the nature of the transition region between the disk photosphere and the supersonic wind. We proposed to use phase resolved spectroscopy of the system, taking advantage of the fact that UX UMa is an eclipsing system, to isolate different regions of the wind and to use a Monte Carlo radiative transfer code to simulate the spectra through the eclipse.

mORCA: sailing bioinformatics world with mobile devices.

PubMed

Díaz-Del-Pino, Sergio; Falgueras, Juan; Perez-Wohlfeil, Esteban; Trelles, Oswaldo

2018-03-01

Nearly 10 years have passed since the first mobile apps appeared. Given the fact that bioinformatics is a web-based world and that mobile devices are endowed with web-browsers, it seemed natural that bioinformatics would transit from personal computers to mobile devices but nothing could be further from the truth. The transition demands new paradigms, designs and novel implementations. Throughout an in-depth analysis of requirements of existing bioinformatics applications we designed and deployed an easy-to-use web-based lightweight mobile client. Such client is able to browse, select, compose automatically interface parameters, invoke services and monitor the execution of Web Services using the service's metadata stored in catalogs or repositories. mORCA is available at http://bitlab-es.com/morca/app as a web-app. It is also available in the App store by Apple and Play Store by Google. The software will be available for at least 2 years. ortrelles@uma.es. Source code, final web-app, training material and documentation is available at http://bitlab-es.com/morca. © The Author(s) 2017. Published by Oxford University Press.

Addressing medical school diversity through an undergraduate partnership at Texas A&M Health Science Center: a blueprint for success.

PubMed

Parrish, Alan R; Daniels, Dennis E; Hester, R Kelly; Colenda, Christopher C

2008-05-01

Imperative to increasing diversity in the physician workforce is increasing the pool of qualified underrepresented minority applicants to medical schools. With this goal in mind, the Texas A&M Health Science Center College of Medicine (A&M College of Medicine) has partnered with Prairie View A&M University (PVAMU), a historically black college and university that is a component of the Texas A&M university system, to develop the undergraduate medical academy (UMA). The UMA was established by legislative mandate in 2003 and is a state-funded program. The authors describe the development of partnership between the A&M College of Medicine and PVAMU, focusing on the key attributes that have been identified for success. The administrative structure of the UMA ensures that the presidents of the two institutions collaborate to address issues of program oversight and facilitates a direct relationship between the dean and associate dean for academic affairs of A&M College of Medicine and the director of the UMA to define the program objectives and structure. The authors delineate the admission process to the UMA, as well as the academic requirements of the program. Students attend lecture series during the academic year and participate in summer programs on the A&M College of Medicine campus in addition to receiving intensive academic counseling and opportunities for tutoring in several subjects. The authors also describe the initial success in medical school admissions for UMA students. This partnership provides a model blueprint that can be adopted and adapted by other medical schools focused on increasing diversity in medicine.

Local probe studies on lattice distortions and electronic correlations in manganites

NASA Astrophysics Data System (ADS)

Lopes, Armandina Maria Lima

Nesta tese apresenta-se um estudo experimental das distorcoes locais e correlacoes electronicas em oxidos magneticos com magnetoresistencia colossal. A tecnica de sonda local - Correlacao Angular Perturbada - e utilizada em amostras caracterizadas quanto as suas propriedades macroscopicas nomeadamente propriedades estruturais, magneticas e electricas, tendo em vista a obtencao de informacao microscopica relevante via gradiente de campo electrico e campo magnetico hiperfino, focando em particular os seguintes aspectos: -Distorcoes de rede e agregados de polaroes no sistema LaMnO3+Delta. E apresentado um estudo dos gradientes de campo electrica e campo magnetico hiperfino em amostras representativas do sistema LaMnO3+Delta, correlacionando estas propriedades locais com a caracterizacao das propriedades macroscopicas, efectuada nas mesmas amostras. Desta forma, foi possivel estudar a natureza microscopica das distorcoes polaronicas. Foi dada especial atencao ao composto com composicao LaMnO3.12 uma vez que este e um sistema padrao de uma manganite ferromagnetica-isoladora que apresenta uma transicao estrutural romboedrica (R)-ortorrombica (O) perto da temperatura ambiente. O estudo revelou que agregados de distorcoes locais sobrevivem ate 776 K, na fase de estrutura media mais simetrica (romboedrica), onde, por simetria, os octaedros MnO6 deveriam ser regulares. Estas distorcoes sao semelhantes as observadas no sistema LaMnO3 onde os octaedros MnO6 apresentam uma distorcao Jahn-Teller colectiva. Com a diminuicao da temperatura observa-se um aumento continuo destes agregados. Abaixo de uma temperatura critica estas distorcoes relaxam acomodando-se numa estrutura com reduzidas distorcoes Jahn-teller. Verificou-se tambem que a transicao estrutural (macroscopica) pode ser entendida como uma transicao de percolacao dos ambientes microscopicos. -Coexistencia das ordens electrica e magnetica no sistema Pr1-xCaxMnO3. E apresentado o primeiro estudo de gradiente de campo electrico no sistema Pr1-xCaxMnO3. Este estudo foi efectuado numa larga gama de temperaturas permitindo estudar localmente as diversas transicoes que este sistema apresenta. Em particular, na regiao do diagrama de fases onde existe ordenamento de carga e orbital (0.32

Magnetic anisotropy engineering: Single-crystalline Fe films on ion eroded ripple surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liedke, M. O.; Koerner, M.; Lenz, K.

We present a method to preselect the direction of an induced in-plane uniaxial magnetic anisotropy (UMA) in thin single-crystalline Fe films on MgO(001). Ion beam irradiation is used to modulate the MgO(001) surface with periodic ripples on the nanoscale. The ripple direction determines the orientation of the UMA, whereas the intrinsic cubic anisotropy of the Fe film is not affected. Thus, it is possible to superimpose an in-plane UMA with a precision of a few degrees - a level of control not reported so far that can be relevant for example in spintronics.

Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. II The Second Year (2009-2010)

NASA Astrophysics Data System (ADS)

Kato, Taichi; Maehara, Hiroyuki; Uemura, Makoto; Henden, Arne; de Miguel, Enrique; Miller, Ian; Dubovsky, Pavol A.; Kudzej, Igor; Kiyota, Seiichiro; Hambsch, Franz-Josef; Tanabe, Kenji; Imamura, Kazuyoshi; Kunitomi, Nanae; Takagi, Ryosuke; Nose, Mikiha; Akazawa, Hidehiko; Masi, Gianluca; Nakagawa, Shinichi; Iino, Eriko; Noguchi, Ryo; Matsumoto, Katsura; Fujii, Daichi; Kobayashi, Hiroshi; Ogura, Kazuyuki; Ohtomo, Sachi; Yamashita, Kousei; Yanagisawa, Hirofumi; Itoh, Hiroshi; Bolt, Greg; Monard, Berto; Ohshima, Tomohito; Shears, Jeremy; Ruiz, Javier; Imada, Akira; Oksanen, Arto; Nelson, Peter; Gomez, Tomas L.; Staels, Bart; Boyd, David; Voloshina, Irina B.; Krajci, Thomas; Crawford, Tim; Stockdale, Chris; Richmond, Michael; Morelle, Etienne; Novák, Rudolf; Nogami, Daisaku; Ishioka, Ryoko; Brady, Steve; Simonsen, Mike; Pavlenko, Elena P.; Ringwald, Frederick A.; Kuramoto, Tetsuya; Miyashita, Atsushi; Pickard, Roger D.; Hynek, Tomáš; Dvorak, Shawn; Stubbings, Rod; Muyllaert, Eddy

2010-12-01

Continued from Kato et al. (2009, PASJ, 61, S395), we collected the times of superhump maxima for 68 SU UMa-type dwarf novae, mainly observed during the 2009-2010 season. The newly obtained data confirmed the basic findings reported in Kato et al. (ibid.): the presence of stages A-C and the predominance of positive period derivatives during stage B in systems with superhump periods shorter than 0.07 d. There was a systematic difference in the period derivatives for the systems with superhump periods longer than 0.075 d between this study and Kato et al. (ibid.). We suggest that this difference was possibly caused by a relative lack of frequently outbursting SU UMa-type dwarf novae in this period regime in the present study. We recorded a strong beat phenomenon during the 2009 superoutburst of IY UMa. A close correlation between the beat period and the superhump period suggests that the changing angular velocity of the apsidal motion of the elliptical disk is responsible for the variation of the superhump periods. We also described three new WZ Sge-type objects with established early superhumps and one with likely early superhumps. We suggest that two systems, VX For and EL UMa, are WZ Sge-type dwarf novae with multiple rebrightenings. The O - C variation in OT J213806.6+261957 suggests that the frequent absence of rebrightenings in very short-Porb objects can be the result of a sustained superoutburst plateau at the epoch when usual SU UMa-type dwarf novae return to quiescence, preceding a rebrightening. We also present a formulation for a variety of Bayesian extensions to traditional period analyses.

The changes in Doppler indices of fetal ductus venosus and umbilical artery after amnioinfusion for women with preterm premature rupture of membranes before 26 weeks' gestation.

PubMed

Hsu, Te-Yao; Hsu, Jenn-Jeih; Fu, Hung-Chun; Ou, Chia-Yu; Tsai, Chih-Chang; Cheng, Bi-Hua; Fang, Fu-Min; Kao, Hui-Fen; Yang, Chun-Yuh; Tsai, Wen Lin; Sung, Chuen Chu; Tsai, Men-Yi

2009-09-01

To investigate the changes in Doppler indices of the fetal ductus venosus (DV) and umbilical artery (UMA) after amnioinfusion in pregnant women with preterm premature rupture of membranes (pPROM). Pregnancies with pPROM and severe oligohydramnios cause sequelae in newborns and mothers. This cross-sectional study included a group of 25 patients with pPROM before 26 weeks' gestation. Color Doppler imaging was used to measure the impedance index and quantitative blood flow in the DV and systolic/diastolic ratio (S/D) of the UMA before and 30 minutes after the end of amnioinfusion. The following velocity parameters were measured: (1) DV peak systolic velocity; (2) DV time-averaged velocity; (3) DV maximum forward velocity during atrial contraction; (4) DV S/D; (5) DV pulsatility index (PI); (6) DV Pourcelots resistance index (RI); (7) fetal heart rate; and (8) UMA S/D. Twenty-one of the 25 patients underwent a total of 27 amnioinfusions. The mean PI and RI of the DV, and S/D of the DV and UMA decreased significantly after amnioinfusion (PI, 0.75 +/- 0.24 vs. 0.60 +/- 0.18, p = 0.009; RI, 0.60 +/- 0.15 vs. 0.50 +/- 0.13; DV S/D, 3.07 +/- 1.81 vs. 2.13 +/- 0.66, p = 0.008; UMA S/D, 3.58 +/- 0.87 vs. 2.88 +/- 0.62, p = 0.001). Amnioinfusion increases the space for the fetuses and reduces the impedance of the fetoplacental circulation. Improvements in DV and UMA flow may benefit fetuses suffering severe oligohydramnios in mid-pregnancy.

THE LEECH EXOPLANET IMAGING SURVEY: ORBIT AND COMPONENT MASSES OF THE INTERMEDIATE-AGE, LATE-TYPE BINARY NO UMa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlieder, Joshua E.; Skemer, Andrew J.; Hinz, Philip

2016-02-10

We present high-resolution Large Binocular Telescope LBTI/LMIRcam images of the spectroscopic and astrometric binary NO UMa obtained as part of the LBT Interferometer Exozodi Exoplanet Common Hunt exoplanet imaging survey. Our H-, K{sub s}-, and L′-band observations resolve the system at angular separations <0.″09. The components exhibit significant orbital motion over a span of ∼7 months. We combine our imaging data with archival images, published speckle interferometry measurements, and existing spectroscopic velocity data to solve the full orbital solution and estimate component masses. The masses of the K2.0 ± 0.5 primary and K6.5 ± 0.5 secondary are 0.83 ± 0.02 M{sub ⊙} and 0.64 ± 0.02 M{sub ⊙},more » respectively. We also derive a system distance of d = 25.87 ± 0.02 pc and revise the Galactic kinematics of NO UMa. Our revised Galactic kinematics confirm NO UMa as a nuclear member of the ∼500 Myr old Ursa Major moving group, and it is thus a mass and age benchmark. We compare the masses of the NO UMa binary components to those predicted by five sets of stellar evolution models at the age of the Ursa Major group. We find excellent agreement between our measured masses and model predictions with little systematic scatter between the models. NO UMa joins the short list of nearby, bright, late-type binaries having known ages and fully characterized orbits.« less

Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group

NASA Astrophysics Data System (ADS)

King, Jeremy R.; Villarreal, Adam R.; Soderblom, David R.; Gulliver, Austin F.; Adelman, Saul J.

2003-04-01

Utilizing Hipparcos parallaxes, original radial velocities and recent literature values, new Ca II H and K emission measurements, literature-based abundance estimates, and updated photometry (including recent resolved measurements of close doubles), we revisit the Ursa Major moving group membership status of some 220 stars to produce a final clean list of nearly 60 assured members, based on kinematic and photometric criteria. Scatter in the velocity dispersions and H-R diagram is correlated with trial activity-based membership assignments, indicating the usefulness of criteria based on photometric and chromospheric emission to examine membership. Closer inspection, however, shows that activity is considerably more robust at excluding membership, failing to do so only for <=15% of objects, perhaps considerably less. Our UMa members demonstrate nonzero vertex deviation in the Bottlinger diagram, behavior seen in older and recent studies of nearby young disk stars and perhaps related to Galactic spiral structure. Comparison of isochrones and our final UMa group members indicates an age of 500+/-100 Myr, some 200 Myr older than the canonically quoted UMa age. Our UMa kinematic/photometric members' mean chromospheric emission levels, rotational velocities, and scatter therein are indistinguishable from values in the Hyades and smaller than those evinced by members of the younger Pleiades and M34 clusters, suggesting these characteristics decline rapidly with age over 200-500 Myr. None of our UMa members demonstrate inordinately low absolute values of chromospheric emission, but several may show residual fluxes a factor of >=2 below a Hyades-defined lower envelope. If one defines a Maunder-like minimum in a relative sense, then the UMa results may suggest that solar-type stars spend 10% of their entire main-sequence lives in periods of precipitously low activity, which is consistent with estimates from older field stars. As related asides, we note six evolved stars (among our UMa nonmembers) with distinctive kinematics that lie along a 2 Gyr isochrone and appear to be late-type counterparts to disk F stars defining intermediate-age star streams in previous studies, identify a small number of potentially very young but isolated field stars, note that active stars (whether UMa members or not) in our sample lie very close to the solar composition zero-age main sequence, unlike Hipparcos-based positions in the H-R diagram of Pleiades dwarfs, and argue that some extant transformations of activity indices are not adequate for cool dwarfs, for which Ca II infrared triplet emission seems to be a better proxy than Hα-based values for Ca II H and K indices.

Crystal Structures of Active Fully Assembled Substrate- and Product-Bound Complexes of UDP-N-Acetylmuramic Acid:l-Alanine Ligase (MurC) from Haemophilus influenzae

PubMed Central

Mol, Clifford D.; Brooun, Alexei; Dougan, Douglas R.; Hilgers, Mark T.; Tari, Leslie W.; Wijnands, Robert A.; Knuth, Mark W.; McRee, Duncan E.; Swanson, Ronald V.

2003-01-01

UDP-N-acetylmuramic acid:l-alanine ligase (MurC) catalyzes the addition of the first amino acid to the cytoplasmic precursor of the bacterial cell wall peptidoglycan. The crystal structures of Haemophilus influenzae MurC in complex with its substrate UDP-N-acetylmuramic acid (UNAM) and Mg2+ and of a fully assembled MurC complex with its product UDP-N-acetylmuramoyl-l-alanine (UMA), the nonhydrolyzable ATP analogue AMPPNP, and Mn2+ have been determined to 1.85- and 1.7-Å resolution, respectively. These structures reveal a conserved, three-domain architecture with the binding sites for UNAM and ATP formed at the domain interfaces: the N-terminal domain binds the UDP portion of UNAM, and the central and C-terminal domains form the ATP-binding site, while the C-terminal domain also positions the alanine. An active enzyme structure is thus assembled at the common domain interfaces when all three substrates are bound. The MurC active site clearly shows that the γ-phosphate of AMPPNP is positioned between two bound metal ions, one of which also binds the reactive UNAM carboxylate, and that the alanine is oriented by interactions with the positively charged side chains of two MurC arginine residues and the negatively charged alanine carboxyl group. These results indicate that significant diversity exists in binding of the UDP moiety of the substrate by MurC and the subsequent ligases in the bacterial cell wall biosynthesis pathway and that alterations in the domain packing and tertiary structure allow the Mur ligases to bind sequentially larger UNAM peptide substrates. PMID:12837790

Crystal structures of active fully assembled substrate- and product-bound complexes of UDP-N-acetylmuramic acid:L-alanine ligase (MurC) from Haemophilus influenzae.

PubMed

Mol, Clifford D; Brooun, Alexei; Dougan, Douglas R; Hilgers, Mark T; Tari, Leslie W; Wijnands, Robert A; Knuth, Mark W; McRee, Duncan E; Swanson, Ronald V

2003-07-01

UDP-N-acetylmuramic acid:L-alanine ligase (MurC) catalyzes the addition of the first amino acid to the cytoplasmic precursor of the bacterial cell wall peptidoglycan. The crystal structures of Haemophilus influenzae MurC in complex with its substrate UDP-N-acetylmuramic acid (UNAM) and Mg(2+) and of a fully assembled MurC complex with its product UDP-N-acetylmuramoyl-L-alanine (UMA), the nonhydrolyzable ATP analogue AMPPNP, and Mn(2+) have been determined to 1.85- and 1.7-A resolution, respectively. These structures reveal a conserved, three-domain architecture with the binding sites for UNAM and ATP formed at the domain interfaces: the N-terminal domain binds the UDP portion of UNAM, and the central and C-terminal domains form the ATP-binding site, while the C-terminal domain also positions the alanine. An active enzyme structure is thus assembled at the common domain interfaces when all three substrates are bound. The MurC active site clearly shows that the gamma-phosphate of AMPPNP is positioned between two bound metal ions, one of which also binds the reactive UNAM carboxylate, and that the alanine is oriented by interactions with the positively charged side chains of two MurC arginine residues and the negatively charged alanine carboxyl group. These results indicate that significant diversity exists in binding of the UDP moiety of the substrate by MurC and the subsequent ligases in the bacterial cell wall biosynthesis pathway and that alterations in the domain packing and tertiary structure allow the Mur ligases to bind sequentially larger UNAM peptide substrates.

The Douro estuarine plume: Detection, processes and dynamics =

NASA Astrophysics Data System (ADS)

Mendes, Renato Paulo dos Santos

O Douro e um dos maiores rios da Peninsula Iberica, constituindo a maior descarga de agua doce para o Oceano Atlântico na costa noroeste portuguesa. A sua pluma estuarina tem particular relevância na dinâmica costeira e na modulacao de fenomenos biogeoquimicos. Sao objetivos desta dissertacao contribuir para a compreensao dos processos fisicos associados a geracao e propagacao da pluma estuarina do Rio Douro no oceano, assim como para o conhecimento dos seus padroes de dispersao e da forma como estes alteram a hidrologia e a circulacao costeira, considerando os agentes forcadores tipicos deste fenomeno (caudal fluvial, vento e mare) e indices climaticos relevantes. Para concretizacao destes objetivos foram desenvolvidas e aplicadas metodologias inovadoras de processamento de dados de detecao remota, assim como novas implementacoes estuarinas e costeiras de modelos numericos. Atraves de imagens MODIS, otimizadas para o estudo de fenomenos costeiros, efetuou-se uma detecao rigorosa da pluma. Identificou-se uma relacao entre o sinal turbido nLw555 e o caudal, demonstrando-se este produto como um bom proxy para a observacao da pluma no oceano. As escalas temporais e espaciais da pluma foram caraterizadas atraves destas imagens, combinadas com dados de caudal fluvial, mare, vento e precipitacao, e tambem com indices climaticos relevantes. Para compreender a propagacao da pluma e caracterizar a sua dinâmica e impacto na circulacao costeira, foi desenvolvida uma aplicacao 3D de modelos estuarinos e costeiros com malhas aninhadas de resolucao variavel. Definiramse e analisaram-se diferentes cenarios de vento e descarga fluvial. A interacao da pluma do Rio Douro e do Minho foi ainda analisada atraves dos resultados de simulacoes baseadas num evento de inverno. Os compositos turbidos mostraram que a pluma e facilmente detetada quando o caudal e maior que 500 m3 s??1. A descarga fluvial e o vento sao os principais forcadores da sua propagacao, enquanto a mare e apenas importante na regiao proxima a embocadura do estuario. Observaram-se relacoes a uma escala interanual entre a turbidez da pluma e os indices climaticos East Atlantic e NAO, com uma correlacao maxima identificada com 1 e 3 meses de desfasamento, respetivamente. Com base nos resultados das simulacoes efetuadas, a pluma e classificada como de larga escala e de advecao superficial, apresentando caracteristicas de uma pluma prototipica. Em condicoes de caudal moderado a elevado, a descarga estuarina e suficiente para gerar uma corrente costeira para norte sem acao do vento. Em eventos de ventos leste, a propagacao da pluma e similar ao caso sem vento, com um aumento da velocidade da corrente. Uma corrente costeira para sul e unicamente identificada sob condicoes de forte vento de oeste. Ventos de norte tendem a estender a pluma para o largo, com uma inclinacao na direcao sudoeste, enquanto ventos de sul intensificam a corrente para norte, sendo a mistura das plumas do Douro e do Minho uma consequencia possivel. A analise desta interacao apontou a contribuicao do Douro como importante na estabilizacao da WIBP e nas trocas de agua entre o oceano e as Rias Baixas. A interacao da pluma do Douro com estuarios localizados a sul da sua foz e a confirmacao in situ da recirculacao observada nos resultados numericos afiguram-se como temas relevantes para investigacoes futuras. None

Católicos, fidelidade conjugal e AIDS: entre a cruz da doutrina moral e as espadas do cotidiano sexual dos adeptos1

PubMed Central

Rios, Luis Felipe; de Aquino, Francisca Luciana; Muñoz-Laboy, Miguel; Oliveira, Cinthia; Parker, Richard

2009-01-01

Neste artigo discutimos a visão da Igreja Católica sobre sexualidade na interface com a epidemia do HIV/AIDS. Nossa reflexão está embasada em pesquisa etnográfica que envolveu dois meses de observação participante do cotidiano de católicos de um bairro popular da Região Metropolitana do Recife, além de contar com entrevistas a onze dos leigos engajados nos serviços religiosos da igreja do bairro e a oito sacerdotes que realizam seus trabalhos religiosos em outras localidades. Nelas abordamos diferentes temáticas relacionadas ao enfrentamento da epidemia da AIDS. Nesse contexto, conjugalidade e fidelidade se afiguram como importantes analisadores de como aqueles lidam com a epidemia, em uma variedade de re-descrições práticas e de re-interpretações conceptuais das assertivas do discurso moral religioso – ainda que, muitos impasses permaneçam em aberto em termos das prerrogativas da Igreja e seus possíveis rebatimentos na saúde sexual dos adeptos. PMID:21765650

LX Leo: A High Mass-Ratio Totally Eclipsing W-type W UMa System

NASA Astrophysics Data System (ADS)

Gürol, B.; Michel, R.; Gonzalez, C.

2017-10-01

We present the results of our investigation of the geometrical and physical parameters of the binary system LX Leo. Based on CCD BVRc light curves, and their analyses with the Wilson-Devinney code, new times of minima and light elements have been determined. According to our solution, the system is a high mass-ratio, totally eclipsing, W-type W UMa system. Combining our photometric solution with the empirical relation for W UMa type systems by Dimitrow & Kjurkchieva (2015), we derived the masses and radii of the components to be M1=0.43 M⊙, M2=0.81 M⊙, R1=0.58 R⊙ and R2=0.77 R⊙. In addition, the evolutionary condition of the system is discussed.

Efeitos do binarismo não resolvido na determinação da função de massa de aglomerados

NASA Astrophysics Data System (ADS)

Kerber, L. O.; Santiago, B. X.

2003-08-01

Através de simulações numéricas buscamos quantificar os efeitos que o binarismo não resolvido causa na determinação da função de massa (MF) de aglomerados estelares. Geramos diagramas cor-magnitude (CMDs) artificiais simulando uma população única, caracterizada por estrelas de mesma idade e composição quí mica, com uma fração de binárias não resolvidas e distribuição em massa das estrelas dada por uma MF do tipo lei de potência. A presença de pares de estrelas não resolvidos faz com que a MF obtida da função de luminosidade (LF) tenha a têndencia de ser mais plana do que a MF que gerou o CMD artificial. Propomos um tratamento de correção para tal efeito. Outro efeito relacionado diz respeito ao alargamento do CMD, que apresenta-se como um indicador do número total de estrelas no domí nio de baixas massas (m < 0.6M¤). Todos os resultados acima possuem uma forte dependência com os erros fotométricos e estão baseados na hipótese de que ambas estrelas do par não resolvido são sorteadas de uma mesma MF de forma independente. O objetivo final é aplicarmos o tratamento aqui desenvolvido para implementarmos a análise da nossa amostra de aglomerados ricos da Grande Nuvem de Magalhães.

Simplificando a luneta com lente de óculos

NASA Astrophysics Data System (ADS)

Canalle, J. B. G.; de Souza, A. C. F.

2003-08-01

A principal ferramenta de trabalho do astrônomo é o telescópio. O manuseio do mesmo é sempre motivo de enorme curiosidade por parte de alunos do ensino fundamental ou médio e até mesmo dos respectivos professores. Visando propiciar o acesso de alunos e professores ou interessados em geral a uma luneta de fácil construção, com materiais alternativos, de fácil localização no comércio, de baixo custo, resistente ao manuseio de alunos, simplificamos a montagem de uma luneta construída com lente de óculos, de 1 ou 2 graus positivos, e monóculo de fotografia, publicado por este autor no CCEF, vol.11(3), 212, 1994. Esta luneta, a qual permite ver as crateras lunares, apresentava como maior dificuldade de construção o tripé e o local de formação da imagem. Substituímos o tripé de madeira por uma simples garrafa PET de 2 litros cheia d'água. No lugar da ocular usamos a lente do monóculo de fotografia (ou visor de fotografia) encaixado dentro de uma bucha de redução curta, de 40 x 32 mm, e esta não mais dentro de uma luva (conexão hidráulica) de 40 mm de diâmetro, mas sim encostada no próprio tubo de PVC móvel (o qual permite o ajuste do foco) de 40 mm de diâmetro e presa a este por outro tubo de 40 mm de diâmetro e 10 cm de comprimento, serrado ao longo do seu comprimento. Com isto podemos ajustar a posição deste tubo de 10 cm também para que uma das suas extremidades coincida com o local de formação da imagem. Desta forma o observador saberá o local exato da formação da imagem, o que não era evidente na montagem anterior e causava uma dificuldade inicial até se descobrir a posição exata em que se deveria colocar o olho. Deste maneira, a montagem inicial que já era simples ficou ainda mais simples, mais barata e mais confortável para o uso. Um exemplar da mesma será exposto durante a XXIX Reunião Anual da Sociedade Astronômica Brasileira para inspeção e uso dos participantes.

Imagens do céu ontem e hoje - um multimídia interativo de astronomia e uma nova exposição no MAST

NASA Astrophysics Data System (ADS)

Caretta, C. A.; Lima, F. P.; Requeijo, F.; Vieira, G. G.; Alves, F.; Valente, M. E. A.; de Almeida, R.; de Garcia, G. C.; Quixadá, A. C.

2003-08-01

"Imagens do Céu Ontem e Hoje" é o título de uma nova exposição que está sendo inaugurada no Museu de Astronomia e Ciências Afins (MCT), que inclui experimentos interativos, maquetes, réplicas e 8 terminais de computador com um multimídia interativo sobre Astronomia para consulta dos visitantes. O multimídia apresenta um conteúdo bastante extenso, que engloba quase todos os temas em Astronomia, consistindo numa fonte de divulgação e pesquisa para um público que vai das crianças até estudantes universitários. O conteúdo está distribuído em mais de 500 páginas de texto divididas em 4 módulos: "O Universo", "Espectroscopia", "Telescópios" e "Observando o Céu". Cada módulo é subdividido em 5 seções, em média, cada uma iniciada por uma animação que ilustra os temas a serem abordados na seção. Ao final da animação, uma lista de temas é apresentada sob o título "Saiba Mais". Para exemplificar, o módulo "O Universo" contém as seguintes seções: "O Universo visto pelo homem", "Conhecendo o Sistema Solar", "Indo além do Sistema Solar", "Nossa Galáxia, a Via-Láctea" e "Indo mais além, a imensidão do Universo". A seção "Conhecendo o Sistema Solar", por sua vez, tem os seguintes temas: "A origem do Sistema Solar", "O Sol", "Os planetas", "Satélites, asteróides, cometas e outros bichos..." e "O Sistema Solar em números". Cada texto é repleto de imagens, quadros, desenhos, esquemas, etc, além de passatempos ao final de cada seção, incluindo jogos interativos, quadrinhos e curiosidades, que auxiliam o aprendizado de forma divertida. Apresentamos neste trabalho as idéias gerais que permearam a produção da exposição, e uma viagem pelo multimídia para exemplificar sua estrutura e conteúdo. O multimídia será posteriormente disponibilizado para o público externo pela página eletrônica do MAst e/ou por intermédio de uma publicação comercial.

Cosmoeducação: uma proposta para o ensino de astronomia

NASA Astrophysics Data System (ADS)

Medeiros, L. A. L.; Jafelice, L. C.

2003-08-01

Entende-se por cosmoeducação o desenvolvimento vivencial da unidade homem-cosmo. Este conceito é norteado pela psicologia transpessoal, que estuda o ser humano em sua totalidade, onde suas relações ecológicas e cósmicas são de grande importância. Constata-se uma necessidade latente no ser humano moderno em resgatar uma relação holística com o Universo. Neste trabalho exploramos meios de cultivar a consciência de que o ser humano constitui parte integrante do cosmo e se relaciona com este com o objetivo de promover em si uma percepção ambiental mais ampla. Nossa hipótese de trabalho inicial foi que o ensino de conteúdos básicos em astronomia realizado através de uma abordagem holística, que incorpore práticas vivenciais correlacionadas àqueles conteúdos, pode despertar no indivíduo sua identidade cósmica. O método que utilizamos é o fenomenológico e o universo desta pesquisa é um grupo de estudantes da disciplina de Astronomia (Curso de Licenciatura em Geografia/UFRN), onde realizamos observação participante, entrevistas, depoimentos e as práticas vivenciais mencionadas. Neste caso estamos desenvolvendo e adaptando exercícios de algumas técnicas terapêuticas de psicologia transpessoal, que um de nós (LALM) tem aplicado no contexto clínico, para trabalhar aspectos cognitivos envolvidos naquele processo de conscientização cósmica. Resultados parciais claramente referendam a hipótese inicial. Um resultado a destacar é fruto de uma dinâmica de representação corporal interiorizada do eclipse lunar, envolvendo um pequeno grupo daqueles estudantes, na qual conteúdos míticos afloraram de maneira espontânea e contundente para todos, sugerindo ressonância, ou pelo menos isomorfismo, entre o macro e o microcosmo. Este e outros resultados são discutidos em detalhe neste trabalho. (PPGECNM/UFRN; PRONEX/FINEP; NUPA/USP; Temáticos/FAPESP).

Kīlauea summit eruption—Lava returns to Halemaʻumaʻu

USGS Publications Warehouse

Babb, Janet L.; Wessells, Stephen M.; Neal, Christina A.

2017-10-06

In March 2008, a new volcanic vent opened within Halemaʻumaʻu, a crater at the summit of Kīlauea Volcano in Hawaiʻi Volcanoes National Park on the Island of Hawaiʻi. This new vent is one of two ongoing eruptions on the volcano. The other is on Kīlauea’s East Rift Zone, where vents have been erupting nearly nonstop since 1983. The duration of these simultaneous summit and rift zone eruptions on Kīlauea is unmatched in at least 200 years.Since 2008, Kīlauea’s summit eruption has consisted of continuous degassing, occasional explosive events, and an active, circulating lava lake. Because of ongoing volcanic hazards associated with the summit vent, including the emission of high levels of sulfur dioxide gas and fragments of hot lava and rock explosively hurled onto the crater rim, the area around Halemaʻumaʻu remains closed to the public as of 2017.Through historical photos of past Halemaʻumaʻu eruptions and stunning 4K imagery of the current eruption, this 24-minute program tells the story of Kīlauea Volcano’s summit lava lake—now one of the two largest lava lakes in the world. It begins with a Hawaiian chant that expresses traditional observations of a bubbling lava lake and reflects the connections between science and culture that continue on Kīlauea today.The video briefly recounts the eruptive history of Halemaʻumaʻu and describes the formation and continued growth of the current summit vent and lava lake. It features USGS Hawaiian Volcano Observatory scientists sharing their insights on the summit eruption—how they monitor the lava lake, how and why the lake level rises and falls, why explosive events occur, the connection between Kīlauea’s ongoing summit and East Rift Zone eruptions, and the impacts of the summit eruption on the Island of Hawaiʻi and beyond. The video is also available at the following U.S. Geological Survey Multimedia Gallery link (video hosted on YouTube): Kīlauea summit eruption—Lava returns to Halemaʻumaʻu

Piezoresponse force microscopy of ferroelectric relaxors =

NASA Astrophysics Data System (ADS)

Kiselev, Dmitry

Nesta tese, ferroelectricos relaxor (I dont know uf the order is correct) de base Pb das familias (Pb,La)(Zr,Ti)O3 (PLZT), Pb(Mg1/3,Nb2/3)O3-PbTiO3 (PMN-PT), Pb(Zn1/3,Nb2/3)O3-PbTiO3 (PZN-PT) foram investigados e analisados. As propriedades ferroelectricas e dielectricas das amostras foram estudadas por metodos convencionais de macro e localmente por microscopia de forca piezoelectrica (PFM). Nos cerâmicos PLZT 9.75/65/35 o contraste da PFM a escala nanometrica foi investigado em funcao do tamanho e orientacao dos graos. Apurou-se que a intensidade do sinal piezoelectrico das nanoestruturas diminui com o aumento da temperatura e desaparece a 490 K (La mol. 8%) e 420 K (9,5%). Os ciclos de histerese locais foram obtidos em funcao da temperatura. A evolucao dos parâmetros macroscopicos e locais com a temperatura de superficie sugere um forte efeito de superficie nas transicoes de fase ferroelectricas do material investigado. A rugosidade da parede de dominio e determinada por PFM para a estrutura de dominio natural existente neste ferroelectrico policristalino. Alem disso, os dominios ferroelectricos artificiais foram criados pela aplicacao de pulsos electricos a ponta do condutor PFM e o tamanho de dominio in-plane foi medido em funcao da duracao do pulso. Todas estas experiencias levaram a conclusao de que a parede de dominio em relaxors do tipo PZT e quase uma interface unidimensional. O mecanismo de contraste na superficie de relaxors do tipo PLZT e medido por PFMAs estruturas de dominio versus evolucao da profundidade foram estudadas em cristais PZN-4,5%PT, com diferentes orientacoes atraves da PFM. Padroes de dominio irregulares com tamanhos tipicos de 20-100 nm foram observados nas superficies com orientacao das amostras unpoled?. Pelo contrario, os cortes de cristal exibem dominios regulares de tamanho micron normal, com os limites do dominio orientados ao longo dos planos cristalograficos permitidos. A existencia de nanodominios em cristais com orientacao esta provisoriamente (wrong Word) atribuida a natureza relaxor de PZN-PT, onde pequenos grupos polares podem formar-se em coindicoes de zero-field-cooling (ZFC). Estes nanodominios sao considerados como os nucleos do estado de polarizacao oposta e podem ser responsaveis pelo menor campo coercitivo para este corte de cristal em particular. No entanto, a histerese local piezoeletrica realizada pelo PFM a escala nanometrica indica uma mudanca de comportamento de PZN-PT semelhante para ambas as orientacoes cristalograficas investigadas. A evolucao das estruturas de dominio com polimento abaixo da superficie do cristal foi investigada. O dominio de ramificacoes e os efeitos de polarizacao de triagem apos o polimento e as medicoes de temperatura tem sido estudados pela PFM e pela analise SEM. Alem disso, verificou-se que a intensidade do sinal piezoelectrico a partir das estruturas de nanodominio diminui com o aumento da temperatura, acabando por desaparecer aos 430 K (orientacao ) e 470 K (orientacao ). Esta diferenca de temperatura nas transicoes de fase local em cristais de diferentes orientacoes e explicada pelo forte efeito de superficie na transicao da fase ferroeletrica em relaxors. A comutacao da polarizacao em relaxor ergodico e nas fases ferroelectricas do sistema PMN-PT foram realizadas pela combinacao de tres metodos, Microscopia de Forca Piezoelectrica, medicao de um unico ponto de relaxamento eletromecânico e por ultimo mapeamento de espectroscopia de tensao. A dependencia do comportamento do relaxamento na amplitude e tempo da tensao de pulso foi encontrada para seguir um comportamento logaritmico universal com uma inclinacao quase constante. Este comportamento e indicativo da progressiva populacao dos estados de relaxamento lento, ao contrario de uma relaxacao linear na presenca de uma ampla distribuicao do tempo de relaxamento. O papel do comportamento de relaxamento, da nao-linearidade ferroelectrica e da heterogeneidade espacial do campo na ponta da sonda de AFM sobre o comportamento do ciclo de histerese e analisada em detalhe. Os ciclos de histerese para ergodica PMN- 10%PT sao mostrados como cineticamente limitados, enquanto que no PMN, com maior teor de PT, sao observados verdadeiros ciclos de histerese ferroelectrica com vies de baixa nucleacao.

Vínculos sobre um modelo de quartessência de Chaplygin usando observações do satélite chandra da fração de massa de gás em aglomerados de galáxias

NASA Astrophysics Data System (ADS)

de Souza, R. S.

2003-08-01

Observações de Supernovas do tipo Ia mostram que a expansão do Universo está acelerando. Segundo as equações de Einstein uma componente com pressão negativa (energia escura) é necessária para explicar a aceleração cósmica. Além da energia escura é usualmente admitido que no Universo há também uma matéria exótica com pressão zero, que é chamada de matéria escura. Essa componente possui um papel fundamental na formação de estruturas no Universo. Recentemente tem se explorado a possibilidade de que matéria e energia escura poderiam ser unificadas através de uma única componente, que tem sido denominada de quartessência. Um exemplo de fluido com essas características é o Gás de Chaplygin Generalizado, que possui uma equação de estado da forma p = -A/ra. Inicialmente consideramos o caso especial a = 1 (gás de Chaplygin) e vinculamos parâmetros do modelo utilizando observações em raios-X do satélite Chandra da fração de massa de gás em aglomerados de galáxias. Uma comparação dos vínculos obtidos com esse teste com outros testes, tais como supernovas e idade do Universo, mostra que esse teste é bastante restritivo. Exibiremos ainda resultados para o caso em que a curvatura é nula e o parâmetro a está compreendido no intervalo -1 < a 1.

Ionic liquid-based ultrasonic/microwave-assisted extraction combined with UPLC-MS-MS for the determination of tannins in Galla chinensis.

PubMed

Lu, Chunxia; Wang, Hongxin; Lv, Wenping; Ma, Chaoyang; Lou, Zaixiang; Xie, Jun; Liu, Bo

2012-01-01

Ionic liquid was used as extraction solvents and applied to the extraction of tannins from Galla chinensis in the simultaneous ultrasonic- and microwave-assisted extraction (UMAE) technique. Several parameters of UMAE were optimised, and the results were compared with of the conventional extraction techniques. Under optimal conditions, the content of tannins was 630.2 ± 12.1 mg g⁻¹. Compared with the conventional heat-reflux extraction, maceration extraction, regular ultrasound- and microwave-assisted extraction, the proposed approach exhibited higher efficiency (11.7-22.0% enhanced) and shorter extraction time (from 6 h to 1 min). The tannins were then identified by ultraperformance liquid chromatography tandem mass spectrometry. This study suggests that ionic liquid-based UMAE is an efficient, rapid, simple and green sample preparation technique.

Treinamento de anastomoses vasculares de baixo custo: o cirurgião vai à feira

PubMed Central

Grahem, Hícaro Donato; Teixeira, Renan Kleber Costa; Feijó, Daniel Haber; Yamaki, Vitor Nagai; Valente, André Lopes; Feitosa, Denilson José Silva; dos Reis, José Maciel Calda; de Barros, Rui Sérgio Monteiro

2017-01-01

Resumo Anastomoses vasculares são procedimentos comuns realizados por grande parte dos cirurgiões e cujo treinamento ocorre principalmente em seres humanos, contrariando os princípios éticos vigentes. Esse fato se deve, sobretudo, à carência e ao alto custo relacionados aos atuais modelos de treinamento. Assim, este estudo visa avaliar a viabilidade de três vegetais para a realização de anastomoses vasculares. Foram utilizadas cinco unidades de cebolinha, vagem e feijão-verde. Em cada uma tentou-se realizar uma anastomose término-terminal. Conseguiu-se a realização da anastomose apenas na vagem e no feijão-verde. Contudo, por apresentar uma menor espessura, o feijão-verde assemelhou-se mais aos vasos humanos. PMID:29930658

An Investigation of Unified Memory Access Performance in CUDA

PubMed Central

Landaverde, Raphael; Zhang, Tiansheng; Coskun, Ayse K.; Herbordt, Martin

2015-01-01

Managing memory between the CPU and GPU is a major challenge in GPU computing. A programming model, Unified Memory Access (UMA), has been recently introduced by Nvidia to simplify the complexities of memory management while claiming good overall performance. In this paper, we investigate this programming model and evaluate its performance and programming model simplifications based on our experimental results. We find that beyond on-demand data transfers to the CPU, the GPU is also able to request subsets of data it requires on demand. This feature allows UMA to outperform full data transfer methods for certain parallel applications and small data sizes. We also find, however, that for the majority of applications and memory access patterns, the performance overheads associated with UMA are significant, while the simplifications to the programming model restrict flexibility for adding future optimizations. PMID:26594668

The Disk Instability Model for SU UMa systems - a Comparison of the Thermal-Tidal Model and Plain Vanilla Model

NASA Astrophysics Data System (ADS)

Cannizzo, John K.

2017-01-01

We utilize the time dependent accretion disk model described by Ichikawa & Osaki (1992) to explore two basic ideas for the outbursts in the SU UMa systems, Osaki's Thermal-Tidal Model, and the basic accretion disk limit cycle model. We explore a range in possible input parameters and model assumptions to delineate under what conditions each model may be preferred.

TIME-VARIABLE ALUMINUM ABSORPTION IN THE POLAR AR URSAE MAJORIS, AND AN UPDATED ESTIMATE FOR THE MASS OF THE WHITE DWARF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bai, Yu; Justham, Stephen; Liu, JiFeng

2016-09-01

We present spectra of the extreme polar AR Ursae Majoris (AR UMa), which display a clear Al i absorption doublet, alongside spectra taken less than a year earlier in which that feature is not present. Re-examination of earlier SDSS spectra indicates that the Al i absorption doublet was also present ≈8 years before our first non-detection. We conclude that this absorbing material is unlikely to be on the surface of either the white dwarf (WD) or the donor star. We suggest that this Al i absorption feature arises in circumstellar material, perhaps produced by the evaporation of asteroids as theymore » approach the hot WD. The presence of any remaining reservoir of rocky material in AR UMa might help to constrain the prior evolution of this unusual binary system. We also apply spectral decomposition to find the stellar parameters of the M dwarf companion, and attempt to dynamically measure the mass of the WD in AR UMa by considering both the radial velocity curves of the H {sub β} emission line and the Na i absorption line. Thereby we infer a mass range for the WD in AR UMa of 0.91 M {sub ⊙} < M {sub WD} < 1.24 M {sub ⊙}.« less

Time-variable Aluminum Absorption in the Polar AR Ursae Majoris, and an Updated Estimate for the Mass of the White Dwarf

NASA Astrophysics Data System (ADS)

Bai, Yu; Justham, Stephen; Liu, JiFeng; Guo, JinCheng; Gao, Qing; Gong, Hang

2016-09-01

We present spectra of the extreme polar AR Ursae Majoris (AR UMa), which display a clear Al I absorption doublet, alongside spectra taken less than a year earlier in which that feature is not present. Re-examination of earlier SDSS spectra indicates that the Al I absorption doublet was also present ≈8 years before our first non-detection. We conclude that this absorbing material is unlikely to be on the surface of either the white dwarf (WD) or the donor star. We suggest that this Al I absorption feature arises in circumstellar material, perhaps produced by the evaporation of asteroids as they approach the hot WD. The presence of any remaining reservoir of rocky material in AR UMa might help to constrain the prior evolution of this unusual binary system. We also apply spectral decomposition to find the stellar parameters of the M dwarf companion, and attempt to dynamically measure the mass of the WD in AR UMa by considering both the radial velocity curves of the H β emission line and the Na I absorption line. Thereby we infer a mass range for the WD in AR UMa of 0.91 M ⊙ < M WD < 1.24 M ⊙.

New precision orbits of bright double-lined spectroscopic binaries. IX. HD 54371, HR 2692, and 16 ursa majoris

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fekel, Francis C.; Williamson, Michael H.; Muterspaugh, Matthew W.

2015-02-01

With extensive sets of new radial velocities we have determined orbital elements for three previously known spectroscopic binaries, HD 54371, HR 2692, and 16 UMa. All three systems have had the lines of their secondaries detected for the first time. The orbital periods range from 16.24 to 113.23 days, and the three binaries have modestly or moderately eccentric orbits. The secondary to primary mass ratios range from 0.50 to 0.64. The orbital dimensions (a{sub 1} sin i and a{sub 2} sin i) and minimum masses (m{sub 1} sin{sup 3} i and m{sub 2} sin{sup 3} i) of the binary componentsmore » all have accuracies of ⩽1%. With our spectroscopic results and the Hipparcos data, we also have determined astrometric orbits for two of the three systems, HR 2692 and 16 UMa. The primaries of HD 54371 and 16 UMa are solar-type stars, and their secondaries are likely K or M dwarfs. The primary of HR 2692 is a late-type subgiant and its secondary is a G or K dwarf. The primaries of both HR 2692 and 16 UMa may be pseudosynchronously rotating, while that of HD 54371 is rotating faster than its pseudosynchronous velocity.« less

Increasing Supercycle Lengths of Active SU UMa-type Dwarf Novae

NASA Astrophysics Data System (ADS)

Otulakowska-Hypka, M.; Olech, A.

2014-12-01

We present observational evidence that supercycle lengths of the most active SU UMa-type stars are increasing during the past decades. We analyzed a large number of photometric measurements from available archives and found that this effect is generic for this class of stars, independently of their evolutionary status. This finding is in agreement with previous predictions and the most recent work of Patterson et al. (2012) on BK Lyn.

Ultraviolet colors of W Ursae Majoris - Gravity darkening, temperature differences, and the cause of W-type light curves

NASA Technical Reports Server (NTRS)

Eaton, J. A.; Wu, C.-C.; Rucinski, S. M.

1980-01-01

The paper presents photometry of the prototype W UMa binary system in three ultraviolet bands with the ANS satellite. It was found that W UMa has low-gravity darkening beta of 0.03; that temperature differences between the components not established by gravity darkening are insignificant; and that the bolometric albedo is not very large. It was also found that W UMa is limb-darkened in the ultraviolet region, and that the inner hemisphere of the less massive component is hotter than that predicted by gravity darkening and the reflection effect. It was concluded that about 20% of the surface area of the component responsible for large gravity darkening is covered by dark spots distributed uniformly in the longitudinal direction. An observational value of the convective darkening exponent of 0.054 plus or minus 0.02 is proposed.

CCD time-resolved photometry of faint cataclysmic variables. I

NASA Technical Reports Server (NTRS)

Howell, Steve; Szkody, Paula

1988-01-01

CCD time-resolved V and B differential light curves are presented for the dwarf novae AR And, FS Aur, TT Boo, UZ Boo, AF Cam, AL Com, AW Gem, X Leo, RZ Leo, CW Mon, SW UMa, and TW Vir. The time-series observations ranged from 2 to 6 hours and have accuracies of 0.025 mag or better for the majority of the runs. Except for AR And, X Leo, CW Mon, and TW Vir, the periods are below the cataclysmic-variable period gap (about 2 hours), and the systems are potential SU UMa stars. Photometric periods for five of the stars are the first such determinations, while those for the other seven generally confirm previous spectroscopic or photometric observations. In several cases, the photometric modulations are large amplitude (up to 0.5 mag). The results on AL Com and SW UMa indicate they may be magnetic variables.

Uma grade de perfis teóricos para estrelas massivas em transição

NASA Astrophysics Data System (ADS)

Nascimento, C. M. P.; Machado, M. A.

2003-08-01

Na XXVIII Reunião Anual da Sociedade Astronômica Brasileira (2002) apresentamos uma grade de perfis calculados de acordo com os pontos da trajetória evolutiva de metalicidade solar, Z = 0.02 e taxa de perda de massa () padrão, para estrelas com massa inicial de 25, 40, 60, 85 e 120 massas solares. Estes perfis foram calculados com o auxílio de um código numérico adequado para descrever os ventos de objetos massivos, supondo simetria esférica, estacionaridade e homogeneidade. No presente trabalho, apresentamos a complementação da grade com os perfis teóricos relativos às trajetórias de Z = 0.02 com taxa de perda de massa dobrada em relação a padrão (2´), e de metalicidade Z = 0.008. Para cada ponto das três trajetórias obtemos os perfis teóricos de Ha, Hb, Hg e Hd, e como esperado eles se apresentam em pura emissão, pura absorção ou em P-Cygni. Para valores de taxa de perda de massa muito baixos (~10-7) não há formação de linhas, o que é visto nos primeiros pontos em todas as trajetórias. Em geral, para um mesmo ponto a componente de emissão diminui e a absorção aumenta de Ha para Hd. É verificado que as trajetórias com Z = 0.02 e padrão possuem menos circuitos (loops) do que as com metalicidade Z = 0.02 e 2´ padrão, e seus perfis são, em geral, menos intensos. Em relação a trajetória de Z = 0.008, verifica-se menos circuitos e maior variação em luminosidade, e seus perfis mostram-se em, algumas trajetórias, mais intensos. Verificamos também que, pontos distintos em uma mesma trajetória, apresentam perfis diferentes para valores similares de luminosidade e temperatura efetiva. Sendo assim, uma grade de perfis teóricos parece ser útil para fornecer uma informação preliminar sobre o estágio evolutivo de uma estrela massiva.

Construção de um catálogo de aglomerados abertos para estudo da dinâmica da estrutura espiral da Galáxia

NASA Astrophysics Data System (ADS)

Carlos, I. M.; Lépine, J. R. D.

2003-08-01

Os aglomerados abertos são objetos de grande valor para o estudo da dinâmica da Galáxia devido esses objetos terem uma faixa de idade relativamente ampla. O trabalho visa estudar a dinâmica da estrutura espiral da Galáxia principalmente através do uso desses aglomerados, uma vez que o estudo da cinemática desses objetos é fundamental para esse objetivo. Nosso grupo trabalha no sentido de construir uma base de dados de aglomerados abertos contendo coordenadas, distância, idade, movimentos próprios e velocidades radiais e já disponibiliza uma nova versão do catálogo de aglomerados abertos o qual é uma compilação de edições anteriores, principalmente Lynga (1987), Mermilliod (1995) e ESO-B (Lauberts 1982). Nossa amostra possui cerca de 1630 aglomerados, mas nem todos os parâmetros acima citados foram determinados em sua totalidade. Para determinarmos esses parâmetros, derivamos as cores intrínsecas das estrelas membro de cada aglomerado a partir de seus tipos espectrais (busca feita no SIMBAD) obtendo assim o excesso de cor individual. A distribuição dos excessos de cor foi então utilizada para derivarmos o avermelhamento médio para cada aglomerado. De maneira similar, os tipos espectrais foram usados para estimar as magnitudes absolutas, e com as magnitudes absolutas e aparentes determinamos a respectiva distribuição do módulo de distância e finalmente a distância. Para determinar as idades foram confeccionados os diagramas cor-magnitude das estrelas de cada aglomerado onde foram superpostas a Seqüência Principal de Idade Zero (ZAMS). Superpomos a ZAMS de Schmidt-Kaler e isócronas de composição solar. Essas isócronas foram usadas para determinação das idades dos aglomerados. Uma vez que não temos ainda resultados finais, apresentamos então alguns diagramas cor-magnitude os quais foram usados para determinação, principalmente, da distância e idade dos aglomerados.

About DR UMa or the CRTS transient CSS110402:135906+554432

NASA Astrophysics Data System (ADS)

Lampens, Patricia,; Van Cauteren, Paul

2017-03-01

We report differential photometric measurements, both unfiltered (filter clear, C) and filtered (filter V), obtained at the Humain station of the Royal Observatory of Belgium (longitude = 5.254, latitude = +50.192, elevation = 280 m) of the CRTS transient CSS110402:135906+554432 (Drake et al. 2009, ApJ 696, 870), which is also identified as DR UMa. The instrumentation is a 16-inch Schmidt-Cassegrain telescope equipped with a Moravian G2-3200 CCD camera.

A Photometric Study of the Eclipsing Binary NSV 1000

NASA Astrophysics Data System (ADS)

Richards, T. J.; Bembrick, C. S.

2018-06-01

Abstract NSV 1000 is an unstudied eclipsing binary in Hydrus. Our photometric research in the period 2014-2016 shows it is a W UMa system with a period of 0.336 579 6(3) d, consistent with the catalogued period. Model fitting to our B, V, and Ic light curves shows the two stars are barely in contact. The parameters derived from the fit satisfy the broadly defined characteristics of a W-type W UMa system.

Eventos de Desconexao na Cauda de Plasma do Cometa P/Halley

NASA Astrophysics Data System (ADS)

Voelzke, M. R.; Fahr, H. J.

2001-08-01

Observacoes cometárias e de vento solar sao comparadas com o propósito de determinar-se as condicoes do vento solar associadas aos eventos de desconexao (DEs) observados em caudas de plasma cometárias. Os dados cometários sao provenientes do The International Halley Watch Atlas of Large-Scale Phenomena. A análise visual sistemática das imagens do atlas revelou, entre outras estruturas morfológicas, 47 DEs ao longo da cauda de plasma do P/Halley. Estes 47 DEs registrados em 47 imagens distintas permitiram a descoberta de 19 origens de DEs, ou seja, o tempo em que as desconexoes iniciaram foi calculado. Os dados do vento solar sao provenientes de medidas feitas in situ pela sonda espacial IMP-8, as quais foram usadas para elaborar a variacao da velocidade do vento solar, densidade e pressao dinâmica durante o intervalo analisado. O presente trabalho compara as atuais teorias conflitantes, baseadas nos mecanismos de formacao, com o intuito de explicar o fenômeno cíclico dos DEs, ou seja, os efeitos de producao iônica, os efeitos de pressao e os efeitos de reconexao magnética sao analisados. Para cada uma das 19 origens de DEs comparou-se a densidade com a respectiva velocidade do vento solar com o intuito de determinar-se uma possível correlacao entre estas origens e os efeitos de pressao dinâmica. Quando da ocorrência de 6 origens de DEs o IMP-8 nao realizou medidas, nos outros 13 casos 10 origens (77%) mostraram uma anticorrelacao entre velocidade e densidade e apenas 3 (23%) revelaram uma tendência similar entre velocidade e densidade. Portanto, a análise inicial demonstra uma fraca correlacao entre as origens dos DEs e os efeitos de pressao.

Determinação da massa de júpiter a partir das órbitas de seus satélites: um experimento didático

NASA Astrophysics Data System (ADS)

Schlickmann, M. S.; Saito, R. K.; Becker, D. A.; Rezende, M. F., Jr.; Cid Fernandes, R.

2003-08-01

Este trabalho apresenta o roteiro piloto de uma prática observacional em astronomia, junto com os primeiros resultados obtidos nesta fase de implementacão. O projeto, que será executado em duas etapas, visa introduzir noções de Astronomia a alunos do Ensino Médio e iniciantes nos cursos de Física. O experimento consiste em medir as órbitas dos satélites Galileanos e, a partir da análise dos dados coletados, verificar a validade da Lei das órbitas de Kepler, determinando a massa do planeta Júpiter. Em uma primeira etapa, as observações serão feitas utilizando um telescópio Meade LX200 10" e câmera CCD para obter uma seqüência de imagens do planeta, que possibilitará medir o movimento de seus satélites. A segunda etapa terá início a partir do funcionamento do telescópio em modo robótico, com a possibilidade de observações via internet por instituições de ensino. Para o desenvolvimento deste experimento foram inicialmente coletadas várias imagens de Júpiter obtidas com os instrumentos citados acima. Estas imagens serviram como base para confecção dos roteiros para a experiência no nível médio e superior. Os roteiros serão inicialmente apresentados em uma home-page. Nela também se buscará uma contextualização histórica da experiência bem como o estabelecimento de relações com professores e alunos, propostas metodológicas e a disponibilização dos programas computacionais necessários para a utilização "on-line" pelos usuários. O projeto conta com apoio da Fundação VITAE.

A Numerical Study of the Plata River Plume Along the Southeastern South American Continental Shelf

DTIC Science & Technology

2005-01-01

Aires Depto. de Oceanografia, Servicio de Hidrografia Naval and Depto. CiEncias de la Atm6sfera y los Ocdanos, Buenos Aires, Argentina ABSTRACT The...descarrega no oceano Aguas de uma bacia de drenagem que cobre uma ampla Area da Amdrica do Sul. Sua pluma extende-se ao longo do norte da Argentina ...Instituto Nacional de Investigaci6n y Orlanski, I. 1976. A simple boundary condition for Desarrollo Pesquero, 109pp. unbounded hyperbolic flows. J

Percepção astronómica de um grupo de alunos do ensino médio de uma escola da rede estadual de São Paulo

NASA Astrophysics Data System (ADS)

de Oliveria, E. F.; Voelzke, M. R.

2009-03-01

Sendo a Astronomia uma das cièncias mais antigas da humanidade, e considerando sua importáncia histórica e cultural, é de extrema releváncia que tópicos relacionados a ela sejam tratados nas escolas. Embora os Parámetros Curriculares Nacionais do Ensino Médio (PCN-EM) e as Orientaçiacute;es Complementares aos Parámetros (PCN+) apontem a importáncia de uma abordagem significativa de conceitos relacionados à Astronomia nas aulas de Física, muitos estudantes terminam o Ensino Médio (EM) sem compreender a razão de certos acontecimentos de origem celeste, ainda que estes façam parte de seu cotidiano e sejam alvos da curiosidade natural dos jovens. Da observação dessa curiosidade em alunos de uma escola pública paulista, na cidade de Suzano, surgiu o interesse em investigar os conhecimentos básicos em Astronomia dos alunos do Ensino Médio desta escola, constituindo-se este como principal objetivo desta pesquisa. Para tanto foi elaborado um questionário de múltipla escolha aplicado inicialmente a 34 alunos do primeiro ano e, posteriormente, a mais 310, distribuídos entre as très séries do Ensino Médio dos períodos matutino e noturno. Dessa forma, observou-se que 73,9% dos estudantes identificaram o Sol como sendo uma estrela, 67,1% mostraram compreender a sucessão entre dia e noite e 52,3% relacionaram o Big Bang à origem do Universo. Em contrapartida, apenas 34,5% relacionaram as estaçíes do ano à inclinação do eixo de rotação da Terra, 21,3% indicaram a influència gravitacional simultánea da Lua e do Sol como responsável pelo fenòmeno das marés, 24,5% indicaram corretamente quais são os objetos celestes mais próximos da Terra, 36,1% identificaram ano-luz como uma medida de distáncia e 34,2% reconheceram as estrelas cadentes como meteoros, evidenciando-se assim o pequeno discernimento dos estudantes quanto aos fenòmenos e termos astronòmicos do cotidiano. Além disso, foram comparadas as respostas de alun! os de diferentes séries e períodos, observando-se, dentre ou tras coi sas, que os estudantes do terceiro ano apresentam um percentual de acertos semelhante ao dos alunos do primeiro, caracterizando que a abordagem de tópicos relacionados à astronomia no Ensino Médio não tem contribuído de forma significativa para uma maior compreensão dos fenòmenos e conceitos.

Compilação de dados atômicos e moleculares do UV ao IV próximo para uso em síntese espectral

NASA Astrophysics Data System (ADS)

Coelho, P.; Barbuy, B.; Melendez, J.; Allen, D. M.; Castilho, B.

2003-08-01

Espectros sintéticos são utéis em uma grande variedade de aplicações, desde análise de abundâncias em espectros estelares de alta resolução ao estudo de populações estelares em espectros integrados. A confiabilidade de um espectro sintético depende do modelo de atmosfera adotado, do código de formação de linhas e da qualidade dos dados atômicos e moleculares que são determinantes no cálculo das opacidades da fotosfera. O nosso grupo no departamento de Astronomia no IAG tem utilizado espectros sintéticos há mais de 15 anos, em aplicações voltadas principalmente para a análise de abundâncias de estrelas G, K e M e populações estelares velhas. Ao longo desse tempo, as listas de linhas vieram sendo construídas e atualizadas continuamente, e alguns acréscimos recentes podem ser citados: Castilho (1999, átomos e moléculas no UV), Schiavon (1998, bandas moleculares de TiO) e Melendez (2001, átomos e moléculas no IV próximo). Com o intuito de calcular uma grade de espectros do UV ao IV próximo para uso no estudo de populações estelares velhas, se fazia necessário compilar e homogeneizar as diversas listas em apenas uma lista atômica e uma molecular. Nesse processo, a nova lista compilada foi correlacionada com outras bases de dados (NIST, Kurucz Database, O' Brian et al. 1991) para atualização dos parâmetros que caracterizam a transição atômica (comprimento de onda, log gf e potencial de excitação). Adicionalmente as constantes de interação C6 foram calculadas segundo a teoria de Anstee & O'Mara (1995) e artigos posteriores. As bandas moleculares de CH e CN foram recalculadas com o programa LIFBASE (Luque & Crosley 1999). Nesse poster estão detalhados os procedimentos citados acima, as comparações entre espectros calculados com as novas listas e espectros observados em alta resolução do Sol e de Arcturus, e uma análise do impacto decorrente da utilização de diferentes modelos de atmosfera no espectro sintético. Ao final, temos uma lista de linhas atômicas com mais de 24.000 linhas e uma lista molecular com as moléculas CN, CH, OH, NH, MgH, C2, TiO Gama, CO, FeH, adequadas ao estudo de estrelas G, K e M e populações estelares velhas.

Adapting a Common Photographic Camera to Take Pictures of the Sky. (Spanish Title: Adaptando Una Camara Fotografica Comun Para Obtener Fotografias del Cielo.) Adaptando Uma Câmera Fotográfica Manual Simples Para Fotografar o Céu

NASA Astrophysics Data System (ADS)

Danhoni Neves, Marcos Cesar; Pereira, Ricardo Francisco

2007-12-01

In this paper will be introduced a method of astrophotography using a non-reflex photographic camera (a low-cost method). It will be revised some photographic processes commonly used nowadays for comparison with the aims of this paper. En este trabajo será introducido un método de astrofotografia que utiliza una cámara fotográfica non-reflex (un método de bajo costo). Serán revisados algunos procesos fotográficos comúnmente utilizados actualmente para comparación con los objetivos de este trabajo. O presente artigo procura introduzir um método de astrofotografia utilizando uma câmera fotográfica não reflex, de baixo custo. É feita uma revisão do processo fotográfico comumente empregado para fins de comparação com os objetivos pretendidos no presente trabalho.

Prevalence of hypothyroidism during pregnancy in a highly specialised referral centre in Mexico.

PubMed

López-Muñoz, Eunice; Ibarra-Avalos, Jorge Antonio; Chan-Verdugo, Rosario Guadalupe; Mateos-Sánchez, Leovigildo; Sánchez-Rodríguez, Olivia

2016-11-01

In order to determine the prevalence of overt and subclinical hypothyroidism, and isolated hypothyroxinemia during pregnancy, thyroid hormone reference values established by UMAE HGO4, IMSS in Mexico City and those suggested by the American Thyroid Association (ATA) were used. All pregnant patients, whose thyroid function was measured and whose pregnancy was monitored and resolved in UMAE HGO4, IMSS from 1 January to 31 December 2013, were included. Significant differences (p = .00419) were observed in the frequency of subclinical hypothyroidism, being higher when using ATA criteria (18.21% vs. 9.66%). The prevalence rate (UMAE HGO4 vs. ATA) for overt hypothyroidism was 1.11 vs. 1.63, for subclinical hypothyroidism 0.84 vs. 1.41 and for isolated hypothyroxinemia 3.17 vs. 2.79 per 1000 consults during the study period. Independently of prevalence rate, it is essential to provide information on the possible risks involved in pregnancy to all women of childbearing age at the time of hypothyroidism diagnosis.

Orbits of 15 visual binaries

NASA Astrophysics Data System (ADS)

Heintz, W. D.

1981-04-01

Micrometer observations in 1979-1980 permitted the computation of substantially revised or new orbital elements for 15 visual pairs. They include the bright stars 52 Ari and 78 UMa (in the UMa cluster), four faint dK pairs, and the probable triple ADS 16185. Ephemerides for equator of data are listed in a table along with the orbital elements of the binaries. The measured positions and their residuals are listed in a second table. The considered binaries include ADS 896, 2336, 6315, 7054, 7629, 8092, 8555, 8739, 13987, 16185, Rst 1658, 3906, 3972, 4529, and Jsp 691.

Order and Progress? The Evolution of Brazilian Defense Strategy

DTIC Science & Technology

2014-03-01

273. 119 Edmundo Sussumo Fujita, “O Brasil E O Conselho de Segurança: Notas Sobre Uma Década de Transição (1985-1995),” Parcerias Estratégicas 1... Brasil No Context Político Regional (2010): 34–42. Desch, Michael C. Civilian Control of the Military: The Changing Security Environment...Press, 1998. Fujita, Edmundo Sussumo. “O Brasil E O Conselho de Segurança: Notas Sobre Uma Década de Transição (1985-1995).” Parcerias Estratégicas 1

A bone tissue engineering strategy based on starch scaffolds and bone marrow cells cultured in a flow perfusion bioreactor

NASA Astrophysics Data System (ADS)

Gomes, Maria Manuela Estima

A Engenharia de Tecidos e uma area cientifica em continua expansao. Os desenvolvimentos conseguidos por esta area tem contribuido significativamente para diversos avancos no campo da Medicina Regenerativa. Esta ciencia interdisciplinar combina os conhecimentos de diversas outras areas, tao distintas como a Engenharia de Materiais e a Biologia, com o objectivo de desenvolver substitutos sinteticos para tecidos humanos. Para se atingir este objectivo utilizam-se, de uma forma generica, combinacoes especificas de celulas e de um material de suporte tridimensional com propriedades adequadas, gerando um material hibrido cujas caracteristicas podem ainda ser moduladas atraves do sistema de cultura usado. A presente tese e centrada no desenvolvimento de estrategias de engenharia de tecido osseo baseadas na cultura in vitro de celulas previamente "semeadas" num suporte tridimensional ("scaffold"). Esta estrategia permite que as celulas adiram ao suporte, proliferem e segreguem matriz extracelular especifica do tecido osseo, ate se obter um substituto artificial funcional com caracteristicas do tecido original, que pode finalmente ser transplantado para tratar o defeito em causa. Para que uma estrategia deste tipo seja bem sucedida, pelo menos tres componentes fundamentais devem ser cuidadosamente estudados: o material de suporte (scaffold), as celulas a usar e o sistema de cultura in vitro. Dai que os principais objectivos desta tese estejam relacionados com estes tres aspectos, nomeadamente: • Desenvolvimento de scaffolds biodegradaveis a partir de polimeros a base de amido de milho que induzam a adesao e proliferacao celular e que apresentem propriedades adequadas, tais como a porosidade e interconectividade entre poros, de forma a proporcionar um ambiente que favoreca o desenvolvimento in vitro de um material hibrido com caracteristicas similares ao osso humano. • Estudo da utilizacao de celulas da medula ossea como uma potencial fonte de celulas para engenharia do tecido osseo, uma vez que estas celulas podem ser facilmente recolhidas do proprio paciente a tratar por metodos nao-invasivos (bioppsia) e em quantidades suficientes. Alem disso, tratando-se de uma fonte de celulas autologas (obtidas do proprio paciente) permitem evitar os riscos de transmissao de doencas contagiosas e/ou de rejeicao pelo sistema imunologico. • Estudo da influencia das condicoes de cultura in vitro geradas por um bioreactor de perfusao (em comparacao com os metodos tradicionais de cultura em condicoes estaticas) no desenvolvimento dos materiais hibridos, compostos pelas celulas e scaffolds, assim como as interaccoes do ambiente proporcionado por este sistema de cultura com as diferentes estruturas/arquitecturas e porosidades dos scaffolds utilizados. Estes objectivos convergem para o objectivo geral desta tese que consistiu no desenvolvimento de uma terapia de engenharia do tecido osseo alternativa as existentes e com potencial para vir a ser posteriormente utilizada na pratica clinica. Este objectivo foi avaliado atraves do estudo da funcionalidade dos materiais hibridos obtidos em diferentes condicoes de cultura in vitro (e utilizando diferentes scaffolds), partindo do principio que o sistema de perfusao poderia eventualmente superar as limitacoes de difusao tipicas dos sistema de cultura estatica e simultaneamente proporcionar estimulos mecânicos as celulas, semelhantes aos encontrados em condicoes fisiologicas. (Abstract shortened by ProQuest.).

Implementação de um algoritmo para a limpeza de mapas da RCFM

NASA Astrophysics Data System (ADS)

Souza, C. L.; Wuensche, C. A.

2003-08-01

A Radiação Cósmica de Fundo em Microondas (RCFM), descoberta por Penzias e Wilson em 1965, é uma das ferramentas mais poderosas para o estudo da cosmologia. Com a descoberta de flutuações de temperatura na RCFM, da ordem de uma parte em 105, pelo COBE (1992), uma nova era teve início. Nos últimos onze anos, diversos instrumentos fizeram novas medidas de alta precisão, refinando os resultados apresentados pelo COBE, culminando com os resultados recentes do satélite WMAP. A análise de dados da RCFM, especialmente no caso de experimentos com pequena cobertura do céu, apresenta uma série de dificuldades devido a emissões de contaminantes externos, tais como a emissão da Galáxia e de fontes pontuais, e de ruídos intrínsecos tanto ao sistema de detecção quanto à estratégia de observação do céu. Uma das soluções típicas para a filtragem de dados brutos de um experimento para medir flutuações de temperatura é aplicar um gabarito (template) e um filtro passa alta ao produzir mapas simplificados (sem considerar matrizes de correlação ou covariância). No caso de experimentos que utilizam detectores HEMT, essa combinação de filtros remove, satisfatoriamente, ruídos do tipo 1/f gerados pela instabilidade no ganho do detector acoplado ao movimento do instrumento, definido pela estratégia de observação. Entretanto, o sinal resultante medido, tanto em simulações quanto em séries temporais reais, sugere que parte do sinal cosmológico pode estar sendo removido junto com o ruído dos detectores. Este trabalho descreve as etapas para a produção de um mapa típico (simulado) e os testes preliminares de um algoritmo para remover ruídos do tipo 1/f introduzidos pela estratégia de observação sem prejudicar a qualidade do sinal cosmológico presente no mapa.

Um estudo espectrofotométrico da variável cataclísmica V3885 Sgr

NASA Astrophysics Data System (ADS)

Ribeiro, F. M. A.; Diaz, M. P.

2003-08-01

Variáveis Cataclísmicas são sistemas binários cerrados compostos de uma anã vermelha que transfere matéria para uma anã branca, em sistemas não magnéticos ocorre a formação de um disco de acresção em torno da anã branca. V3885 Sgr é uma variável cataclísmica classificada como sendo do tipo nova-like. É apresentado um estudo espectrofotométrico de V3885 Sgr de alta resolução temporal feito na região do visível. A região observada é centrada em Ha e abrange também a linha de HeI 6678. O primeiro resultado obtido neste estudo é a determinação do período orbital a partir de medidas da velocidade radial da linha de Ha como sendo 0,20716071(22) dias, resolvendo inconsistências quanto a esse valor na literatura e definindo uma efeméride a longo prazo para o sistema. Com este período e as medidas de velocidade radial do perfil de linha de Ha foi construído um diagrama de massas, através do qual restringimos as massas das componentes estelares do sistema e limitamos a inclinação orbital do sistema. Foram construídos diagramas de Greenstein para as linhas de Ha e HeI, onde os espectros médios em cada intervalo de fase são representados lado a lado em escala de cinza, indicando a existência de uma emissão intensa proveniente da parte posterior do disco. A partir da tomografia Doppler obtivemos perfis de emissividade radial para o disco tanto para a linha de Ha como para HeI. Os resultados obtidos são comparados com os de outros sistemas estudados com a mesma técnica. Serão apresentados também resultados da tomografia de flickering para o sistema.

Transferências orbitais dentro do modelo quase bicircular no sistema Terra-Lua-Sol

NASA Astrophysics Data System (ADS)

Corrêa, A. A.; de Almeida Prado, A. F. B.; Stuchi, T. J.; Beaugé, C.

2003-08-01

O problema quase bicircular planar consiste na determinação da dinâmica de um corpo, de massa desprezível, que se move sob o campo gravitacional de três corpos. No caso estudado, o quarto corpo é considerado um satélite artificial e os demais são a Terra, a Lua e o Sol, formando o sistema de três corpos. Este modelo permite a construção de uma hamiltoniana similar a do problema restrito de três corpos (PRTC), incluindo termos periódicos não autônomos, provenientes da presença do Sol, portanto pode ser entendido como uma perturbação ao PRTC. Suas órbitas periódicas aparecem isoladas e possuem o mesmo período solar. Os pontos de equilíbrio colineares possuem o mesmo caráter de estabilidade linear dos pontos lagrangianos (L1, L2 e L3) do PRTC, sendo do tipo sela x centro x centro, instável na direção x e estáveis nas direções y e z. As órbitas periódicas tridimensionais ao redor do ponto colinear é chamada órbita Halo. O objetivo deste trabalho é determinar órbitas de transferências de baixo consumo de combustível para um veículo espacial partindo de uma órbita de estacionamento ao redor da Terra em direção a uma órbita Halo do ponto L1, situado entre a Terra e Lua. Esta tarefa pode ser transformada no problema de valor de contorno: dado um ponto inicial na órbita de estacionamento, um ponto final na órbita halo e o tempo de transferência, deseja-se obter a trajetória que liga estes dois pontos e que minimize os incrementos de velocidade do veículo. Essas transferências são realizadas baseadas no método de Lambert e analisadas de modo a fornecer um baixo consumo. Posteriormente, é feita uma comparação de consumo com as órbitas de transferência equivalentes do PRTC.

Size-resolved chemistry of aerosols produced by Halema'uma'u eruption 2008-2009, Kilauea Volcano, Hawai'i

NASA Astrophysics Data System (ADS)

Ilyinskaya, E.; Martin, R.; Edmonds, M.; Sutton, A. J.; Elias, T.; Werner, C. A.

2009-12-01

A dense quiescent plume has been emitted continuously from the 2008 eruptive vent in Halema'uma'u crater since March 2008. Aerosol particles were sampled near-source in the young plume (<30 s old) in May 2008 and April 2009, and at 10 km downwind (April 2009 only). We also sampled the plume from Pu'u O'o vent both near-source and 8-10 km downwind (2007 to 2009). Sampling was performed using filter packs and a cascade impactor that collects and segregates PM10 (particle matter <10 μm) into 14 size fractions. The collected PM was analysed for SO42-, F-, Cl-, Na+, K+, Ca2+ and Mg2+. Our results show a distinctive peak of sulphate abundance at ~0.3-0.5 μm in the 2008 and 2009 summit samples. The total SO42- mass concentration collected in each sampling run correlates well with that of metals but poorly with Cl- and F-. Downwind measurements of PM from Halema'uma'u and Pu'u O'o show SO42- in the same narrow size bin (0.3-0.5 μm) with concentrations similar to, or higher than at source. It is noteworthy that the particles appear not to have grown when the plume has drifted 5-10 km downwind. However, a 1 μm size mode of SO42- seen at Pu'u O'o crater rim (not seen at Halema'uma'u) is absent from the downwind plume. This result leads us to believe that the particles grow rapidly after emission but get scavenged efficiently once they reach a certain size (>0.5 μm). The formation of aerosol measured downwind is dominated by oxidation of SO2 to SO42- in the plume. The ratio of Cl-/SO42- is higher downwind than at the source in both Halema'uma'u and Pu'u O'o plumes, and increases further during rainfall; we propose that the Cl--bearing aerosol is formed by dissolution of HCl gas into water droplets in the plume.

STELLAR ARCHAEOLOGY IN THE GALACTIC HALO WITH THE ULTRA-FAINT DWARFS. VI. URSA MAJOR II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dall'Ora, M.; Ripepi, Vincenzo; Marconi, Marcella

2012-06-10

We present a B, V color-magnitude diagram (CMD) of the Milky Way dwarf satellite Ursa Major II (UMa II), spanning the magnitude range from V {approx} 15 to V {approx} 23.5 mag and extending over an 18 Multiplication-Sign 18 arcmin{sup 2} area centered on the Galaxy. Our photometry goes down to about 2 mag below the Galaxy's main-sequence turnoff that we detected at V {approx} 21.5 mag. We have discovered a bona fide RR Lyrae variable star in UMa II, which we use to estimate a conservative dereddened distance modulus for the galaxy of (m - M){sub 0} = 17.70more » {+-} 0.04 {+-} 0.12 mag, where the first error accounts for the uncertainties of the calibrated photometry, and the second reflects our lack of information on the metallicity of the star. The corresponding distance to UMa II is 34.7{sup +0.6}{sub -0.7}({sup +2.0}{sub -1.9}) kpc. Our photometry shows evidence of a spread in the Galaxy's subgiant branch, compatible with a spread in metal abundance in the range between Z = 0.0001 and Z = 0.001. Based on our estimate of the distance, a comparison of the fiducial lines of the Galactic globular clusters M68 and M5 ([Fe/H] = -2.27 {+-} 0.04 dex and -1.33 {+-} 0.02 dex, respectively), with the position on the CMD of spectroscopically confirmed Galaxy members, may suggest the existence of stellar populations of different metal abundance/age in the central region of UMa II.« less

Period Variations in the Close Binary BM UMa

NASA Astrophysics Data System (ADS)

Virnina, Natalia A.; Panko, Elena; Sergienko, O. G.; Murnikov, Boris A.; Gubin, E. G.; Klabukova, A. V.; Movchan, A. I.

2010-12-01

We present the results of analysing of the light curve and O-C variations in the eclipsing system BM UMa, based on V-band observations which cover the period from JD 2454933 to 2454961 using two robotic remotely-controlled telescopes of Tzec Maun Observatory (USA) along with observations made with the RK-600 telescope of Odessa Astronomical Observatory. The full light curve displays a total primary eclipse with a duration 0.06 of the period, or 24 minutes, and a partial secondary eclipse, with both maxima of equal magnitude. For our obesrvations, we determined the statistically optimal values of the initial epoch of T0 = 2454944.2814 ± 0.0001 and orbital period of P = 0.d271226± 0.000002. The depths of primary and secondary minima are nearly equal, 0.m838 ± 0.006 and 0.m748 ± 0.006, respectively. The physical parameters of the system were calculated using the Wilson-Devinney code, appended with the Monte Carlo search algorithm. The result establishes BM UMa as a contact system (fillout factor 10.7%) with parameters: mass ratio 0.538 ± 0.001, inclination 86.°815 ± 0.005, and temperatures of components 4700 ± 20 K and 4510 ± 10 K. The more massive component is larger and cooler. The 72 archival and 11 newly-obtained times of light minimum cover the interval 1961-2010 and allowed us to exclude possible systematic period variations in BM UMa and to determine an initial epoch of HJD 2447927.382 and orbital period of P = 0.d2712209± 0.0000006.

On summary measure analysis of linear trend repeated measures data: performance comparison with two competing methods.

PubMed

Vossoughi, Mehrdad; Ayatollahi, S M T; Towhidi, Mina; Ketabchi, Farzaneh

2012-03-22

The summary measure approach (SMA) is sometimes the only applicable tool for the analysis of repeated measurements in medical research, especially when the number of measurements is relatively large. This study aimed to describe techniques based on summary measures for the analysis of linear trend repeated measures data and then to compare performances of SMA, linear mixed model (LMM), and unstructured multivariate approach (UMA). Practical guidelines based on the least squares regression slope and mean of response over time for each subject were provided to test time, group, and interaction effects. Through Monte Carlo simulation studies, the efficacy of SMA vs. LMM and traditional UMA, under different types of covariance structures, was illustrated. All the methods were also employed to analyze two real data examples. Based on the simulation and example results, it was found that the SMA completely dominated the traditional UMA and performed convincingly close to the best-fitting LMM in testing all the effects. However, the LMM was not often robust and led to non-sensible results when the covariance structure for errors was misspecified. The results emphasized discarding the UMA which often yielded extremely conservative inferences as to such data. It was shown that summary measure is a simple, safe and powerful approach in which the loss of efficiency compared to the best-fitting LMM was generally negligible. The SMA is recommended as the first choice to reliably analyze the linear trend data with a moderate to large number of measurements and/or small to moderate sample sizes.

A New Look at the Eclipse Timing Variation Diagram Analysis of Selected 3-body W UMa Systems

NASA Astrophysics Data System (ADS)

Christopoulou, P.-E.; Papageorgiou, A.

2015-07-01

The light travel effect produced by the presence of tertiary components can reveal much about the origin and evolution of over-contact binaries. Monitoring of W UMa systems over the last decade and/or the use of publicly available photometric surveys (NSVS, ASAS, etc.) has uncovered or suggested the presence of many unseen companions, which calls for an in-depth investigation of the parameters derived from cyclic period variations in order to confirm or reject the assumption of hidden companion(s). Progress in the analysis of eclipse timing variations is summarized here both from the empirical and the theoretical points of view, and a more extensive investigation of the proposed orbital parameters of third bodies is proposed. The code we have developed for this, implemented in Python, is set up to handle heuristic scanning with parameter perturbation in parameter space, and to establish realistic uncertainties from the least squares fitting. A computational example is given for TZ Boo, a W UMa system with a spectroscopically detected third component. Future options to be implemented include MCMC and bootstrapping.

Chromospheric activity on late-type star DM UMa using high-resolution spectroscopic observations

NASA Astrophysics Data System (ADS)

Zhang, LiYun; Pi, QingFeng; Han, Xianming L.; Chang, Liang; Wang, Daimei

2016-06-01

We present new 14 high-resolution echelle spectra to discuss the level of chromospheric activity of DM UMa in {He I} D3, {Na I} D1, D2, Hα, and {Ca II} infrared triplet lines (IRT). It is the first time to discover the emissions above the continuum in the {He I} D3 lines on 2015 February 9 and 10. The emission on February 9 is the strongest one ever detected for DM UMa. We analysed these chromospheric active indicators by employing the spectral subtraction technique. The subtracted spectra reveal weak emissions in the {Na I} D1, D2 lines, strong emission in the Hα line, and clear excess emissions in the {Ca II} IRT lines. Our values for the EW8542/EW8498 ratio are on the low side, in the range of 1.0-1.7. There are also clear phase variations of the level of chromospheric activity in equivalent width (EW) light curves in these chromospheric active lines (especially the Hα line). These phenomena might be explained by flare events or rotational modulations of the level of chromospheric activity.

Metals in the caudal scutes of Morelet's crocodile (Crocodylus moreletii) from the southern Gulf of Mexico.

PubMed

Trillanes, C E; Pérez-Jiménez, J C; Rosíles-Martínez, R; González-Jáuregui, M

2014-10-01

Caudal scutes were collected from 92 Morelet's crocodiles (Crocodylus moreletii) between May and August 2012, in three Wildlife Management and Use Units (UMAs, from its name in Spanish) and three wild sites in Campeche, Mexico. The UMAs are intensive, with an ex situ approach to manage crocodiles in captivity. The concentrations of arsenic, mercury, lead, nickel, cadmium and chromium were analyzed in each sample. As and Pb were detected in all samples, Hg in 86 and Ni in 74. The metal concentrations estimated were higher than most of the concentrations reported for skin, tail tip and caudal scutes in other crocodilians around the world. The concentration of As, Pb and Ni was significantly greater in the free-ranging groups than in the captive groups in UMAs (p < 0.05). Negative linear relationship was estimated between the snout-vent length and the concentration of Pb (in five groups) and Ni (in three groups). In this region C. moreletii is exposed to metals contamination and more studies are necessary to establish if represents a risk to their populations.

Calibração do sistema imageador do telescópio MASCO

NASA Astrophysics Data System (ADS)

Mejía, J.; D'Amico, F.; Villela, T.; Braga, J.

2003-08-01

O MASCO (MÁScara COdificada) é um telescópio imageador de raios-X e gama atualmente configurado para operar na faixa de 50 a 600 keV com uma resolução angular de 14 minutos de arco num campo de visada total circular de 23,5° de diâmetro. O MASCO está totalmente operacional e deverá ser lançado em um balão estratosférico no segundo semestre de 2003 para realizar observações durante ~20 horas a ~40 km de altitude. O telescópio utiliza uma máscara codificada de padrão uniformemente redundante modificado (MURA) de dimensões 19 ´ 19. Esse padrão pertence a uma subclasse de MURAs que apresenta anti-simetria de 90° e conseqüentemente permite a utilização da técnica de subtração de variações sistemáticas de ruído de fundo através de utilização da configuração anti-máscara, obtida com uma simples rotação da máscara. Neste trabalho apresentamos resultados de calibrações em laboratório que tiveram como objetivo testar o sistema imageador. Imagens de fontes radioativas foram obtidas com o telescópio em configuração de vôo, com a máscara girando. Serão discutidos os resultados desses testes e as técnicas desenvolvidas para eliminar ambigüidades de posição de fontes, otimização da relação sinal-ruído e observação de fontes fora do campo totalmente codificado. O sistema de máscara/antimáscara mostrou-se capaz de aumentar a relação sinal-ruído de ~60% para fontes intensas (100 s). Com a máscara girando, a técnica de reconstrução de imagens desenvolvida identificou a posição exata da fonte e não introduziu perda de sensibilidade. Imagens de uma fonte colocada a 8,3° - fora do campo totalmente codificado do telescópio -, mostraram uma diminuição de ~40% na relação sinal/ruído em relação ao centro do campo de visada, o que se deve à codificação incompleta pela máscara e à absorção parcial do fluxo pelos detectores de blindagem.

A estabilidade dos PAHS em função da energia da radiação interestelar nas faixas UV e raios-X

NASA Astrophysics Data System (ADS)

Pinotti, R.; Costa, R. K.; Boechat-Roberty, H. M.; Lago, A.; Souza, G. B.

2003-08-01

A nebulosa CRL 618, uma proto-nebulosa planetária cuja nuvem molecular espessa envolve uma estrela B0, contém uma grande quantidade de C2H2 e CH4. Estas moléculas são consideradas os tijolos da criação de grandes moléculas carbonadas como os Hidrocarbonetos Policíclicos Aromáticos (PAHs). Esta nebulosa, por estar exposta a intensos campos de UV e Raios-X, é uma região de fotodissociação molecular que propicia a formação de novas moléculas, confirmada pela presença de C4H2 e C6H6 (Benzeno), que é a unidade básica dos PAHs. Atribui-se a esta família de moléculas orgânicas duas propriedades fundamentais, a resistência para sobreviver ao campo de radiação UV interestelar e a geração das bandas de emissão não identificadas (UIR) observadas no infravermelho. No entanto, alguns autores questionam a resistência dos PAHs ao campo de radiação UV interestelar. Empregando a técnica de Espectrometria de Massas por Tempo de Vôo, no modo de coincidência fotoelétron-fotoíon, estudamos a ionização e fragmentação das seguintes moléculas: Benzeno, Benzeno deuterado, Naftaleno, Antraceno e Fenantreno. Utilizamos uma fonte de Hélio monocromática em 21,21 eV (584,5 Å) e a radiação Síncroton do Laboratório Nacional de Luz Síncroton (LNLS) em diferentes energias nas proximidades da borda do C 1s ( 290 eV). Comprovamos a estabilidade dos PAHs sob ação de UV (21,21 eV), onde eles apresentam um baixo nível de fotodissociação, produzindo fragmentos ionizados com rendimento total na ordem de 5 por cento em relação ao íon molecular pai. Entretanto, em altas energias, na faixa de Raios-X, a quebra destas moléculas torna-se mais intensa, com a produção de muitos fragmentos. Como uma das rotas de fragmentação do Naftaleno é [(C10H8) = > (C6H6+) + (C4H2) + (e-)], e como temos as evidências observacionais da existência do C4H2 e C6H6 na nebulosa CRL 618, sugerimos que este ambiente também possui o Naftaleno.

Ballistic Blocks Surrounding Kilauea's Caldera

NASA Astrophysics Data System (ADS)

Swanson, D.; Zolkos, S.; Haravitch, B.

2010-12-01

Thousands of lithic blocks dot the surface around Kilauea’s caldera, erupted ballistically at the end of the 1790 eruption or soon thereafter. Most of the blocks occur in the western and southern sectors, probably reflecting the proximity of vents on the caldera floor. We mapped the ejecta field, measuring most of the blocks with nominal diameters ((a+b+c)/3) more than 75 cm and many of the smaller ones, noting distinctive lithologies. The distributions, sizes, and lithologies suggest 7-8 different ballistic bursts from 3-4 generalized vent areas. We measured 15 blocks with nominal diameters (ND) of 150-201 cm, 169 blocks with ND 100-149 cm, 308 blocks with ND 75-99 cm, 684 blocks with ND 50-74 cm, and 545 blocks with ND 25-49 cm. The smaller blocks were measured only in outlying areas, where they were the largest in the neighborhood, but they occur throughout the field. Twelve blocks with ND >150 cm lie within 1.7 km west and south of the center of Halema`uma`u; a vent near this location likely erupted the blocks. Three of the largest blocks, however, are 2.2-2.7 km north of Halema`uma`u and probably came from a more northerly vent. This interpretation is supported by the distributions of all blocks with ND >100 cm, which define at least 4, and possibly 5, different dispersal lobes; three cluster near Halema`uma`u, one is slightly north, and the one with the three large blocks is still farther north. The blocks have typical lithologies for Kilauea’s summit, including coarse basalt or fine gabbro derived from the centers of thick flows, solidified lakes, or small intrusions. Three lithologies are distinctive and help define 3, possibly 4, discrete bursts. Blocks of fine-grained basalt riddled with segregation veins occur only in a lobe 1.3 km wide reaching as far as 1.8 km southwest of Halema`uma`u; this lobe overlaps slightly with one defined by block size but is mostly distinct and probably indicates a separate burst. A cluster of blocks with puffy, somewhat fluidal rinds forms a distinct lobe 800 m wide out to 1.8 km southeast of Halema`uma`u. The cluster also contains many cored bombs and a few juvenile bombs and lapilli without cores. This is the only ballistic lobe that contains much juvenile material, though older fall and surge deposits of 1790 and pre1790 vintage also carry cored bombs and juvenile lapilli. This lobe is coextensive with one defined by block size. The largest ballistic lobe has abundant, commonly oxidized blocks of olivine-rich basalt, some verging on picrite. The main lobe, about 900 m wide, extends 0.9-3.6 km southeast of Halema`uma`u; three olivine-rich blocks between 100 and 150 cm ND occur 2.4 to 3.3 km out. A possible second lobe of olivine-rich blocks occurs out to 1.6 km due south of Halema`uma`u. The lobes indicate a directionality and inclined ejection angle for at least some of the ballistic eruptions, as was true for the observed, but much smaller, ballistic eruptions in 1924. The scarcity of juvenile ejecta argues for phreatic eruptions that were likely initiated at or below the water table, today about 600 m below the caldera rim. If so, some ballistic blocks weighing a few tonnes were thrown at least 600 m above the vent. The dynamics of these explosive eruptions are under study.

Peculiaridades observadas no espectro da estrela magnética HD 190073 - candidata a estrela do tipo Ae de Herbig

NASA Astrophysics Data System (ADS)

Franco, G. A. P.; Pogodin, M. A.; Lopes, D. F.

2003-08-01

Apresentaremos os resultados de uma investigação espectroscópica cooperativa da estrela magnética HD 190073. As observações foram conduzidas no Observatório do Pico dos Dias (LNA/MCT), European Southern Observatory (ESO, Chile), e Crimean Astrophysical Observatory (CrAO, Ucrânia), entre 1998 e 2002. Discutiremos em detalhe um dos padrões mais marcantes do espectro desse objeto - as multicomponentes em absorção das linhas Ca ii K e H. De acordo com nossos resultados, a estrutura complexa desse perfil permaneceu constante durante várias decadas (dos anos 30 até os anos 80) após o que apresentou mudanças marcantes nos anos 90. Essa variabilidade apresenta óbvia contradição com a interpretação tradicional desse fenômeno como o resultado de espalhamento ressonante atuando seletivamente sobre o vento estelar em distâncias diferentes. Propomos uma explicação alternativa com base em uma topologia especí fica do campo magnético estelar. Essa hipótese permite, também, explicar uma série de outras peculiaridades observadas no envoltório de HD 190073, tais como: (a) a baixa velocidade de rotação pode ser o resultado da interação entre a magnetosfera estelar e um disco equatorial hipotético; (b) o gás circumstelar acumulado em loops magnéticos em latitudes intermediárias pode estimular a formação de regiões gasosas densas a distâncias intermediárias da estrela, onde linhas em emissão com perfil simples são formadas.

Assessment of the usability of a digital learning technology prototype for monitoring intracranial pressure.

PubMed

Carvalho, Lilian Regina de; Évora, Yolanda Dora Martinez; Zem-Mascarenhas, Silvia Helena

2016-08-29

to assess the usability of a digital learning technology prototype as a new method for minimally invasive monitoring of intracranial pressure. descriptive study using a quantitative approach on assessing the usability of a prototype based on Nielsen's ten heuristics. Four experts in the area of Human-Computer interaction participated in the study. the evaluation delivered eight violated heuristics and 31 usability problems in the 32 screens of the prototype. the suggestions of the evaluators were critical for developing an intuitive, user-friendly interface and will be included in the final version of the digital learning technology. avaliar a usabilidade de um protótipo educacional digital sobre um novo método para monitoração da pressão intracraniana de forma minimamente invasivo para enfermeiros e médicos. estudo descritivo com abordagem quantitativa sobre a avaliação de usabilidade de um protótipo com base nas dez Heurísticas de Nielsen. Participaram quatro especialistas da área de Interação Humano Computador. a avaliação resultou em oito heurísticas violadas e 31 problemas de usabilidade nas 32 telas do protótipo. as sugestões dos avaliadores foram cruciais para o desenvolvimento de uma interface amigável e intuitiva e serão consideradas na versão final da tecnologia educacional digital. evaluar la usabilidad de un prototipo educacional digital sobre un nuevo método para monitorización de la presión intracraneal, de manera mínimamente invasiva. estudio descriptivo con abordaje cuantitativo sobre la evaluación de usabilidad de un prototipo con base en las diez reglas Heurísticas de Nielsen. Participaron cuatro especialistas del área de Interacción Humana Computador. la evaluación resultó en ocho reglas heurísticas violadas y 31 problemas de usabilidad en las 32 pantallas del prototipo. las sugestiones de los evaluadores fueron cruciales para el desarrollo de una interfaz amigable e intuitiva y éstas serán consideradas en la versión final de la tecnología educacional digital.

VizieR Online Data Catalog: UY UMa and EF Boo compiled time of minima (Yu+, 2017)

NASA Astrophysics Data System (ADS)

Yu, Y.-X.; Zhang, X.-D.; Hu, K.; Xiang, F.-Y.

2017-11-01

In order to construct the (O-C) diagram to analyze the period change of UY UMa, we have performed a careful search for all available times of light minima. A total of 76 times of light minima were collected and listed in Table 2. >From the literatures and two well-known databases (i.e., the O-C gateway (http://var.astro.cz/ocgate) and the Lichtenknecker database of the BAV (http://www.bav-astro.de/LkDB/index.php)), we have collected a total of 75 available times of light minima for EF Boo, which are summarized in Table 3. (3 data files).

Método numérico das diferenças finitas no domínio do tempo aplicado a ondas Alfvén em plasma astrofísico

NASA Astrophysics Data System (ADS)

Dos Santos, L. C.; Kintopp, J. A.; Jatenco-Pereira, V.; Opher, R.

2003-08-01

Ondas Alfvén em plasma astrofísico têm sido objeto de intenso estudo nas últimas décadas pelo fato de apresentarem papel importante em muitas áreas de pesquisa na astrofísica. Particularmente são importantes no mecanismo de aquecimento da coroa solar; em ventos estelares; em jatos galácticos e extragalácticos; em discos protoestelares, etc. A formulação para diferenças finitas no domínio do tempo (FDTD), aplicada a plasma magnetizado é desenvolvida para estudo das propriedades de ondas Alfvén em três dimensões (3D-FDTD). O método é aplicado inicialmente a um plasma homogêneo e isotérmico imerso em uma região com campo magnético externo B0, que sofre uma pequena perturbação. Uma vez gerada a onda, esta perturbação é retirada e, então analisamos a evolução temporal das ondas, bem como a forma de seu amortecimento.

Rapid Light-curve Changes and Probable Flip-flop Activity of the W UMa-type Binary V410 Aur

NASA Astrophysics Data System (ADS)

Luo, Xia; Wang, Kun; Zhang, Xiaobin; Deng, Licai; Luo, Yangping; Luo, Changqing

2017-09-01

New photometric observations of a W UMa system, V410 Aur, were carried out over 10 nights from 2014 December 19 to 2015 February 8, from which four sets of light curves were obtained. The light curves show many unusual behavioral features, including changing occultation depths, transit minima, and asymmetric maxima. The four sets of light curves have been separately analyzed with the Wilson-Devinney method. The results suggest a totally eclipsing contact configuration for the system. Over a surprisingly short time span of only 52 days, the dominant spot distortion phase jumped twice between phases 0.0 and 0.5. The light-curve variations can be interpreted by the presence of two cool spots on the massive component. Based on our analysis, it is further suggested that the peculiar behavioral patterns are probably caused by the presence of two permanent, active large spots separated in longitude by about 180°, whose locations remain almost unchanged throughout. Our study demonstrates that the system has been undergoing typical flip-flop activity. We therefore conclude that V410 Aur is a W UMa-type system exhibiting flip-flop activity.

A teoria da percolação aplicada às galáxias aneladas peculiares

NASA Astrophysics Data System (ADS)

Poppe, P. C. R.; Martin, V. A. F.; de Medeiros, N. G. F.; Faúndez-Abans, M.; Oliveira-Abans, M.

2003-08-01

Formulado no final da década de 50, o modelo de percolação concentra-se em descrever o meio poroso, que será visto neste trabalho como uma rede de canais aleatórios, por onde escoa um fluido determinístico. Se o número de canais for suficientemente grande, então eles estarão ligados e o meio se tornará permeável à passagem do fluido. Neste caso, dizemos que houve a percolação do fluido. Reformulando o modelo acima, podemos escrever um código particularmente adaptado para simulações em Galáxias, onde iremos supor que os canais formam um reticulado, e que cada sítio da rede representa um poro que será interpretado como uma região ativa de formação estelar. Para cada elo teremos um pequeno canal ligando dois sítios vizinhos, que poderá, após um tempo "t", induzir ou não a formação de uma região ativa no poro vizinho. Para simular a passagem desta região ativa através dos poros, diremos que um elo está aberto com probabilidade p e fechado com probabilidade 1-p. Dessa forma, passamos a imaginar configurações de elos abertos e fechados, onde cada configuração ocorre com uma certa probabilidade, dada por p|A|(1-p)|F|, onde |A| é o número de elos abertos e |F| o número de elos fechados da configuração. A expressão anterior só tem importância física se |A| e |F| forem ambos finitos, pois, caso contrário, a probabilidade de ocorrência de uma dada configuração será sempre nula. Neste trabalho, foram considerados dados cinemáticos publicados na literatura bem como aqueles obtidos pelos autores a partir de observações fotométricas realizadas no Observatório de Las Campanãs, em 1994, para a Galáxia Anelada Peculiar HRG 03401. Mostraremos que para certos valores de p, situados entre 0,5 e 0,6, os clusters assim formados irão simular, de maneira coerente, o referido objeto.

Abundâncias de oxigênio e enxofre nas estrelas de tipo solar da vizinhança solar

NASA Astrophysics Data System (ADS)

Requeijo, F.; Porto de Mello, G. F.

2003-08-01

Alguns resultados sugerem que o Sol seja 58% mais abundante em oxigênio que o meio interestelar local. Esta anomalia parece estender-se para o carbono e o criptônio. Entre as possíveis explicações deste fenômeno estão: uma supernova de tipo II que tenha enriquecido a nebulosa protosolar, tornando-a superabundante em oxigênio; um episódio de infall de material pobre em metais sobre o disco Galático, diluindo o meio interestelar local ou uma migração dinâmica do Sol de uma órbita mais interna da Galáxia para sua posição atual. A escolha entre estes cenários exige o conhecimento preciso da abundância solar em relação às anãs G da vizinhança. Neste contexto, o oxigênio e enxofre, são elementos-chave por serem ambos produzidos pelas supernovas de tipo II, devendo portanto possuir o mesmo padrão de abundância. Este projeto visa esclarecer qual a posição do Sol na distribuição local de abundâncias de enxofre e oxigênio para uma amostra de estrelas de tipo solar com idades e metalicidades bem conhecidas. Para tal, analisamos espectros de alta resolução e alta relação sinal-ruído nas regiões espectrais de ll 6300, 7774 (O) e l8695 (S). Para o enxofre encontramos que o Sol parece ser uma estrela típica dentre as da vizinhança, e que este elemento não mostra a sobreabundância para baixas metalicidades, já bem estabelecida para o oxigênio. Discutimos as abundâncias do enxofre no contexto da Evolução Química da Galáxia. Apresentamos resultados preliminares muito precisos para a linha proibida do oxigênio l6300 e comparamos estes com os obtidos para o tripleto em l7774. Quantificamos os efeitos não-ETL presentes no tripleto em função dos parâmetros atmosféricos estelares.

Correlação de longo alcance em sistemas binários de raios-x usando remoção de flutuações

NASA Astrophysics Data System (ADS)

Pereira, M. G.; Moret, M. A.; Zebende, G. F.; Nogueira, E., Jr.

2003-08-01

Neste trabalho é proposta uma metodologia de analise de series temporais de fontes astrofísicas, baseada no método proposto por Peng et al. (1994) e Liu et al. (1999), o qual consiste na idéia de que uma série temporal correlacionada pode ser mapeada por um processo de busca de auto-similaridades em diversas escalas de tempo n. Removendo as eventuais tendências e integrando o sinal observado, é obtida uma medida do desvio médio quadrático das flutuações do sinal integrado F(n)~na, onde a representa o fator de escala associado com a auto-similaridade da correlação de longo alcance do sinal. Baseado nos valores obtidos de a, é possível distinguir entre os casos de sinais não-correlacionados, tipo ruído branco (a = 0,5), sinal anti-persistentes (a < 0,5) e sinal persistente (a > 0,5). Usando esta metodologia, foram analisadas 129 curvas de luz de sistemas binários de raios-X, provenientes do banco de dados públicos de observações feitas pelo instrumento All Sky Monitor, a bordo do satélite Rossi X-Ray Timing Explorer (ASM-RXTE). Foram identificadas a presença de a'0,5 em mais de 90% dos sistemas estudados, implicando em dizer que as flutuações de intensidade observadas apresentam correlação de auto-similaridade, sem entretanto, indícios de apresentarem uma escala de tempo característica das flutuações de intensidade. Sistemas onde são observadas erupções (flares), apresentam sistematicamente a > 0,5, característica esta, possivelmente associada com persistência das flutuações de densidade de disco ou taxa de acréscimo de massa. Os sistemas com curvas de luz onde nao são observadas as erupções apresentam uma distribuição normal centrada em a~0,62+/-0,10. Referências ¾ Peng, C.-K., Buldyrev, S.V., Havlin, S., Simons, M., Stanley, H.E., e Goldberg, A.L., Phys. Rev. E, (49), 1685 (1994). ¾ Liu, Y., Gopikrishnan, P., Cizeau, P., Meyer, M., Peng,C.-K., e Stanley, H.E., Phys. Rev. E, (60), 1390 (1999).

Evolução temporal de discos circunstelares em estrelas Be

NASA Astrophysics Data System (ADS)

Fernandes, M. V. M.; Leister, N. V.; Levenhagen, R. S.

2003-08-01

A pesquisa do mecanismo que leva uma estrela do tipo Be a perder massa e formar um envelope circunstelar, nomeado como fenômeno Be, é uma questão em aberto, intrigante, e que adquire contornos interessantes em face às informações espectroscópicas de alta resolução. Nesta última década, consolida-se a idéia de que a forma destes envelopes é de tipo discóide, obedecendo a uma lei Kepleriana de velocidades, e mais ainda, recentemente há evidências de que a distribuição de matéria nestes discos pode assumir um caráter de anel. Medidas de algumas dimensões de discos circunstelares puderam ser obtidas pela análise de espectros de alta resolução e alta relação sinal-ruído para as estrelas Be: alpha Eri (HD 10144, B3Vpe), omicron And (HD 217675, B6IIIpe), e eta Cen (HD el972, B1.5Vne), no período dos anos de 1991 a 2001. Alguns modelos clássicos de envelope predizem uma distribuição de massa que decresce suavemente a partir da superfície estelar. Entretanto, considerando que a separação de picos de emissão em perfis de linhas do HeI e H-alpha, alargados por efeitos cinemáticos, é função do raio estelar e da velocidade rotacional projetada (vsini); nossos resultados sugerem a presença de um anel de matéria circunstelar, que aparece logo após a ejeção do material fotosférico, imediatamente acima da superfície estelar, e que se expande para raios maiores ao longo do tempo, eventualmente desconectando-se da superfície por uma região de densidade de matéria mínima. Tais interpretações revivem a idéia de que anéis de matéria circunstelar podem ser os responsáveis por algumas variabilidades em perfis de linhas de emissão, como as variações V/R.

Comparação entre cirurgia aberta e endovascular no tratamento do aneurisma da artéria poplítea: uma revisão

PubMed Central

Gonçalves, Ana Fernanda Fagundes; Pelek, Carlos Augusto; Nogueira, Lorena Slusarz; de Carvalho, Renan Francisco; Stumpf, Matheo Augusto Morandi; Gomes, Ricardo Zanetti; Kluthcovsky, Ana Claudia Garabeli Cavalli

2018-01-01

Resumo Os aneurismas de artéria poplítea correspondem a 70% dos aneurismas periféricos e o tratamento é cirúrgico, com controvérsias sobre os resultados da via endovascular. Este estudo objetivou realizar uma revisão da literatura sobre a comparação entre cirurgia aberta e endovascular no tratamento dos aneurismas da artéria poplítea. A pesquisa foi realizada utilizando os termos apropriados nos portais de periódicos LILACS e MEDLINE, com a seleção de 15 artigos. Um total de 5.166 procedimentos cirúrgicos foram comparados, sendo 3.930 cirurgias abertas e 1.236 cirurgias endovasculares. A cirurgia aberta com bypass venoso continua sendo o padrão-ouro. A cirurgia endovascular apresenta menor tempo de internação e é uma opção viável em pacientes eletivos, com baixa expectativa de vida, alto risco cirúrgico, comorbidades e mais idosos, desde que tenham anatomia favorável para o procedimento. Contudo, são necessários estudos de longo prazo para estabelecer os reais benefícios e indicações das duas técnicas, como o ensaio clínico randomizado controlado.

Avaliação do conhecimento de pacientes diabéticos sobre medidas preventivas do pé diabético em Maringá (PR)

PubMed Central

Carlesso, Guilherme Pereira; Gonçalves, Mariana Helena Barboza; Moreschi, Dorival

2017-01-01

Resumo Contexto O atual envelhecimento da população tem gerado maior predominância de doenças crônicas, como o diabetes, a qual está associada a um risco elevado de complicações crônicas e agudas. Entre essas, o pé diabético (PD) destaca-se por possuir alta incidência e grande poder mutilador. Objetivo Avaliar o conhecimento da população diabética das Unidades Básicas de Saúde (UBS) de Maringá (PR) sobre a prevenção do PD. Métodos Estudo descritivo, quantitativo, tipo inquérito por entrevista. A população estudada foi composta por 80 portadores de diabetes, cadastrados em UBS de Maringá (PR). A coleta de dados buscou levantar dados sociodemográficos e epidemiológicos, bem como as atitudes de controle do diabetes e do autocuidado para prevenção do PD. Resultados Do total de entrevistados, nove não realizavam qualquer tipo de exame para controle do diabetes e a renda mensal predominante foi de até um salário mínimo. O grau de escolaridade e a renda mensal não se mostraram relevantes em relação ao conhecimento de cuidados preventivos do PD e nem uma maior adesão a hábitos de vida saudáveis. O cuidado com o PD tende a melhorar à medida que exista uma compreensão mais clara dos fatores que conduzem à perda do membro e um crescente consenso sobre a gestão de vários aspectos clínicos do cuidado com o pé. Conclusão Existe uma falta de aprendizado das medidas preventivas, mesmo nos pacientes com algum nível de instrução, o que induz a uma prática deficiente de cuidados.

Uma Visão do Universo Segundo um Grupo de Alunos do Ensino Médio de São Paulo

NASA Astrophysics Data System (ADS)

Elias, D. S.; Araújo, M.; Amaral, L. H.; Voelzke, M. R.; Araújo, M.

2005-08-01

A astronomia, embora seja uma ciência popular, com inúmeras descobertas de interesse público, ainda é apresentada desconsiderando-se os aspectos históricos e científicos relacionados ao seu desenvolvimento, sendo geralmente veiculada nos meios de comunicação de maneira pouco esclarecedora e não raro com imprecisões. Neste trabalho analisou-se a concepção de um grupo de estudantes de Ensino Médio sobre conceitos de astronomia, visando identificar sua visão de mundo a respeito do Universo, envolvendo idéias sobre espaço e tempo. Para issso, foi aplicado um questionário em três escolas da grande São Paulo em um espaço amostral de 270 alunos. Constatou-se que, embora o ensino de astronomia esteja previsto nos PCNEM, os resultados obtidos na pesquisa mostram que há grande deficiência no conhecimento dos temas investigados. Nesse sentido, verificou-se que apenas 20% dos alunos eram capazes de relacionar a sucessão das semanas com as fases da lua, enquanto 28% associaram as estações do ano à inclinação do eixo de rotação da Terra. Por outro lado, somente 23% dos alunos tinham noções das distâncias entre os objetos celestes próximos da Terra e 56% conseguiram relacionar o Big Bang com a origem do Universo. Finalmente, constatou-se que 37% reconheciam o ano-luz como uma unidade de distância e 60% reconheciam o Sol como sendo uma estrela. Apesar de 60% dos alunos indicarem que a escola é a principal fonte para aquisição dos conhecimentos de astronomia, conclui-se que seus conceitos nessa área ainda são inadequados, havendo necessidade de ampliação e aprimoramento da abordagem desses conteúdos nos ambientes escolares.

Fiber-optic components for optical communicatios and sensing =

NASA Astrophysics Data System (ADS)

Marques, Carlos Alberto Ferreira

Nos ultimos anos, a Optoelectronica tem sido estabelecida como um campo de investigacao capaz de conduzir a novas solucoes tecnologicas. As conquistas abundantes no campo da optica e lasers, bem como em comunicacoes opticas tem sido de grande importancia e desencadearam uma serie de inovacoes. Entre o grande numero de componentes opticos existentes, os componentes baseados em fibra optica sao principalmente relevantes devido a sua simplicidade e a elevada de transporte de dados da fibra optica. Neste trabalho foi focado um destes componentes opticos: as redes de difraccao em fibra optica, as quais tem propriedades opticas de processamento unicas. Esta classe de componentes opticos e extremamente atraente para o desenvolvimento de dispositivos de comunicacoes opticas e sensores. O trabalho comecou com uma analise teorica aplicada a redes em fibra e foram focados os metodos de fabricacao de redes em fibra mais utilizados. A inscricao de redes em fibra tambem foi abordado neste trabalho, onde um sistema de inscricao automatizada foi implementada para a fibra optica de silica, e os resultados experimentais mostraram uma boa aproximacao ao estudo de simulacao. Tambem foi desenvolvido um sistema de inscricao de redes de Bragg em fibra optica de plastico. Foi apresentado um estudo detalhado da modulacao acustico-optica em redes em fibra optica de silica e de plastico. Por meio de uma analise detalhada dos modos de excitacao mecanica aplicadas ao modulador acustico-optico, destacou-se que dois modos predominantes de excitacao acustica pode ser estabelecidos na fibra optica, dependendo da frequencia acustica aplicada. Atraves dessa caracterizacao, foi possivel desenvolver novas aplicacoes para comunicacoes opticas. Estudos e implementacao de diferentes dispositivos baseados em redes em fibra foram realizados, usando o efeito acustico-optico e o processo de regeneracao em fibra optica para varias aplicacoes tais como rapido multiplexador optico add-drop, atraso de grupo sintonizavel de redes de Bragg, redes de Bragg com descolamento de fase sintonizaveis, metodo para a inscricao de redes de Bragg com perfis complexos, filtro sintonizavel para equalizacao de ganho e filtros opticos notch ajustaveis.

Biofunctionality and immunocompatibility of starch-based biomaterials

NASA Astrophysics Data System (ADS)

Marques, Alexandra Margarida Pinto

A procura de novos biomateriais que desempenhem funcoes especificas sem, no entanto, desencadearem respostas negativas nos hospedeiros constitui um desafio permanente e actual nesta area. Biomateriais degradaveis foram uma das solucoes propostas e actualmente em aplicacao mas, embora possuam vantagens inegaveis, tambem apresentam alguns problemas nomeadamente no que diz respeito aos seus produtos de degradacao e respectivos efeitos negativos consequentes. Outros biomateriais, entre os quais polimeros de origem natural, foram propostos considerando que os seus produtos de degradacao poderao ser incorporados nas vias metabolicas normais evitando efeitos secundarios no hospedeiro. Ate ao momento, e apesar de todos os esforcos e do grande numero de dispositivos biomedicos desenvolvidos, o biomaterial ideal para uma aplicacao especifica ainda nao foi encontrado. Estudos com polimeros biodegradaveis a base de amido demonstraram que estes materiais possuem propriedades promissoras abrindo novas perspectivas para a sua possivel aplicacao numa variedade de aplicacoes biomedicas. Assim, de modo a demonstrar que estes materiais tem de facto potencial para serem utilizados em, por exemplo, substituicao ossea, sistemas de libertacao controlada, cimentos osseos e engenharia de tecidos, seria imperativo avaliar com maior profundidade a resposta biologica desencadeada pelos mesmos. Para tal foi delineado um plano de trabalhos com tres objectivos principais: i) avaliar a citocompatibilidade dos polimeros e compositos a base de amido com monitorizacao da citotoxicidade e analise da adesao e proliferacao celulares nas suas superficies. Foi dada particular atencao a osteoblastos considerando uma possivel aplicacao ortopedica para estes materiais; ii) estabelecer modelos in vitro para analisar e prever, tanto quanto possivel, uma situacao real de resposta inflamatoria; iii) validar os resultados in vitro com um modelo in vivo ja estabelecido em outros trabalhos de analise da resposta inflamatoria a biomateriais. Em resumo, os estudos de citocompatibilidade e imunocompatibilidade demonstraram que os polimeros e compositos a base de milho sao biomateriais promissores. Em comparacao com os biomateriais degradaveis actualmente em uso, possuem propriedades capazes de induzir um comportamento semelhante, ou mesmo melhor, em termos de citotoxicidade. Estes dados foram reconfirmados com a adesao e proliferacao de celulas do tipo osteoblastos na superficie de alguns dos materiais a base de amido, que demonstraram ser comparaveis as observadas no PLLA, evidenciando a possibilidade de usar esses materiais em aplicacoes ortopedicas. As conclusoes retiradas dos estudos in vitro e in vivo de imunocompatibilidade reforcam as observacoes das experiencias de citocompatibilidade e em conjunto, evidenciam a possibilidade de utilizacao dos biomateriais a base de amido, com fraca capacidade de desencadear uma reaccao inflamatoria, em aplicacoes biomedicas. (Abstract shortened by ProQuest.).

Detecção inesperada de efeitos de lentes fracas em grupos de galáxias pouco luminosos em raios-X

NASA Astrophysics Data System (ADS)

Carrasco, R.; Mendes de Oliveira, C.; Sodré, L., Jr.; Lima Neto, G. B.; Cypriano, E. S.; Lengruber, L. L.; Cuevas, H.; Ramirez, A.

2003-08-01

Obtivemos, como parte do programa de verificação científica do GMOS Sul, imagens profundas de três grupos de galáxias: G97 e G102 (z~0,4) e G124 (z = 0,17). Esses alvos foram selecionados a partir do catálogo de fontes extensas de Vikhlinin (1998), por terem luminosidades em raios X menores que 3´1043 ergs s-1, valor cerca de uma ou duas ordens de grandeza inferior ao de aglomerados de galáxias. O objetivo primário dessas observações é o estudo da evolução de galáxias em grupos. Grupos são ambientes menos densos que aglomerados, contêm a grande maioria das galáxias do Universo mas que, até o momento, foram estudados detalhadamente apenas no Universo local (z~0). Com esses dados efetuamos uma análise estatística da distorção na forma das galáxias de fundo (lentes gravitacionais fracas) como forma de inferir o conteúdo e a distribuição de massa nesses grupos apesar de que, em princípio, esse efeito não deveria ser detectado uma vez que os critérios de seleção adotados previlegiam sistemas de baixa massa. De fato, para G124 obtivemos apenas um limite superior para sua massa que é compatível com sua luminosidade em raios X. De modo contrário e surpreendente, os objetos G102 e G097, aparentam ter massas que resultariam em dispersões de velocidade maiores que 1000 km s-1, muito maiores do que se espera para grupos de galáxias. Com efeito, para G097 obtivemos, a partir de dados do satélite XMM, uma estimativa para a temperatura do gás intragrupo de kT = 2,6 keV, que é tipica de sistemas com dispersões de velocidade de ~ 600 km s-1, bem característica de grupos. Essas contradições aparentes entre lentes fracas e raios X podem ser explicadas de dois modos: i) a massa obtida por lentes estaria sobreestimada devido à superposição de estruturas massivas ao longo da linha de visada ou ii) a temperatura do gás do meio intra-grupo reflete o potencial gravitacional de estruturas menores que estariam se fundindo para formar uma estrutura maior.

Life-cycle optimization model for distributed generation in buildings

NASA Astrophysics Data System (ADS)

Safaei, Amir

O setor da construcao e responsavel por uma grande parte do consumo de energia e emissoes na Uniao Europeia. A Geracao Distribuida (GD) de energia, nomeadamente atraves de sistemas de cogeracao e tecnologias solares, representa um papel importante no futuro energetico deste setor. A otimizacao do funcionamento dos sistemas de cogeracao e uma tarefa complexa, devido as diversas variaveis em jogo, designadamente: os diferentes tipos de necessidades energeticas (eletricidade, aquecimento e arrefecimento), os precos dinamicos dos combustiveis (gas natural) e da eletricidade, e os custos fixos e variaveis dos diferentes sistemas de GD. Tal torna-se mais complexo considerando a natureza flutuante das tecnologias solares termicas e fotovoltaicas. Ao mesmo tempo, a liberalizacao do mercado da eletricidade permite exportar para a rede, a electricidade gerada localmente. Adicionalmente, a operacao estrategica de um sistema de GD deve atender aos quadros politicos nacionais, se tiver como objetivo beneficiar de tais regimes. Alem disso, considerando os elevados impactes ambientais do setor da construcao, qualquer avaliacao energetica de edificios rigorosa deve tambem integrar aspetos ambientais, utilizando uma abordagem de Ciclo de Vida (CV). Uma avaliacao de Ciclo de Vida (ACV) completa de um sistema de GD deve incluir as fases relativas a operacao e construcao do sistema, bem como os impactes associados a producao dos combustiveis. Foram analisadas as emissoes da producao de GN, as quais variam de acordo com a origem, tipo (convencional ou nao-convencional), e estado (na forma de GN Liquefeito (GNL) ou gas). Do mesmo modo, o impacte dos sistemas solares e afetado pela meteorologia e radiacao solar, de acordo com a sua localizacao geografica. Sendo assim, uma avaliacao adequada dos sistemas de GD exige um modelo de ACV adequado a localizacao geografica (Portugal), integrando tambem a producao de combustivel (GN), tendo em conta as suas diferentes fontes de abastecimento. O principal objetivo desta tese de doutoramento foi desenvolver um modelo para otimizar o desenho e operacao de sistemas de GD para o setor da construcao de edificios comerciais em Portugal, considerando os respetivos Impactes de Ciclo de Vida (IAVC) e Custos de Ciclo de Vida (CCV), de modo a satisfazer as necessidades energeticas do edificio. Tres tipos de tecnologias de cogeracao (Micro-Turbinas, Motores de combustao interna, e Celulas combustiveis de Oxido solido), e dois tipos de tecnologias de energia solar, solar termica e fotovoltaica, constituem os sistemas de GD que sao acoplados aos sistemas convencionais. Foi desenvolvido um modelo de CV, tendo em conta todos os impactes relacionados com a construcao e operacao dos sistemas de energia, bem como os processos a montante relacionados com a producao do GN. Em particular, o mix de GN consumido em Portugal em 2011 foi identificado (60% da Nigeria, 40% da Argelia) e os impactes relativos a cada uma das vias de abastecimento foram avaliados separadamente para quatro categorias de impacte ambiental: Consumo de Energia Primaria (CEP), Gases com Efeito de Estufa (GEE), acidificacao, e eutrofizacao. Devido a importancia das emissoes de GEE na formulacao de politicas, foi tambem realizada uma analise de incerteza as emissoes de GEE do GN fornecido a Portugal. Foi desenvolvido um modelo matematico, em linguagem de Programacao General Algebraic Modeling System (GAMS), que utiliza os resultados da ACV dos sistemas de energia e as suas implicacoes economicas para minimizar o CCV e IACV ao longo de um horizonte de planeamento definido pelo decisor. Foram derivadas fronteiras otimas de Pareto, representando as relacoes entre o tipo de IACV (CEP, GEE, acidificacao, eutrofizacao) e CCV decorrentes da satisfacao das necessidades energeticas do edificio. Para aumentar a robustez do modelo, dada a incerteza dos precos dos combustiveis (GN e eletricidade), foi desenvolvido um modelo de custos robusto para os sistemas de GD, que e menos afetado por perturbacoes relativas aos custos de combustivel. A aplicacao do modelo proposto foi testada num caso de estudo real, um edificio comercial localizado na cidade de Coimbra, em Portugal.

Sonification of Kepler Field SU UMa Cataclysmic Variable Stars V344 Lyr and V1504 Cyg

NASA Technical Reports Server (NTRS)

Tutchton, Roxanne M.; Wood, Matt A.; Still, Martin D.; Howell, Steve B.; Cannizzo, John K.; Smale, Alan P.

2012-01-01

Sonification is the conversion of quantitative data into sound. In this work we explain the methods used in the sonification of light curves provided by the Kepler instrument from Q2 through Q6 for the cataclysmic variable systems V344 Lyr and V1504 Cyg . Both systems are SU UMa stars showing dwarf nova outbursts and superoutbursts as well as positive and negative superhumps. Focused sonifications were done from average pulse shapes of each superhump, and separate sonifications of the full, residual light curves were done for both stars. The audio of these data reflected distinct patterns within the evolutions of supercycles and superhumps that matched pervious observations and proved to be effective aids in data analysis.

A new family of magnetic stars: the Am stars

NASA Astrophysics Data System (ADS)

Blazère, A.; Neiner, C.; Petit, P.; Lignières, F.

2016-12-01

We presented the discovery of an ultra-weak field in three Am stars, β UMa, θ Leo, and Alhena, thanks to ultra-deep spectropolarimetric observations. Two of the three stars of this study shown peculiar magnetic signatures with prominent positive lobes like the one of Sirius A that are not expected in the standard theory of the Zeeman effect. Alhena, contrary to Sirius A, β UMa and θ Leo, show normal signatures. These detections of ultra-weak fields in Am stars suggest the existence of a new family of magnetic intermediate-mass stars: the Am stars. However the various shapes of the signatures required further observation to identify the physical processes at work in these stars. A preliminary explanation is based on microturbulence.

Biomarcadores de função endotelial em doenças cardiovasculares: hipertensão

PubMed Central

Neves, Josynaria Araújo; Neves, Josyanne Araújo; Oliveira, Rita de Cássia Meneses

2016-01-01

Resumo A incidência de hipertensão arterial sistêmica está aumentando mundialmente. Sua prevenção baseia-se na identificação dos hipertensos. Atualmente, biomarcadores são utilizados com fins de diagnosticar, estratificar e prognosticar doenças. Neste estudo, objetivou-se revisar artigos dos últimos cinco anos relacionados a biomarcadores nas doenças cardiovasculares. Pesquisaram-se dados de PubMed, SciELO, Science Direct e MEDLINE, mediante as palavras-chave: hipertensão arterial, biomarcadores cardiovasculares, óxido nítrico, função endotelial e dimetilarginina assimétrica. Os estudos levantados mostram que as doenças cardiovasculares possuem uma etiologia complexa. Neste artigo, evidenciaram-se interações entre o óxido nítrico e a dimetilarginina assimétrica na regulação, no metabolismo e na determinação dos níveis intracelulares, e reviram-se outros biomarcadores relacionados à hipertensão. Alguns estudos indicam os biomarcadores como uma ferramenta útil na predição de eventos cardíacos, e outros reportam que eles contribuem pouco para a avaliação. A seleção e combinação desses pode ser uma alternativa para validar o uso dos biomarcadores devido à pouca especificidade existente para diagnosticar a hipertensão. PMID:29930594

Trombose induzida pelo calor endovenoso: relato de dois casos tratados com rivaroxabana e revisão da literatura

PubMed Central

de Araujo, Walter Junior Boim; Timi, Jorge Rufino Ribas; Erzinger, Fabiano Luiz; Caron, Filipe Carlos

2016-01-01

Resumo Define-se trombose induzida pelo calor endovenoso como a propagação do trombo a partir de uma veia superficial em direção a uma veia mais profunda. Em geral, é considerada clinicamente insignificante quando não há propagação do trombo para o sistema venoso profundo. Essa condição pode ser tratada com terapia anticoagulante, embora a observação pareça ser suficiente, principalmente para graus menores. Neste estudo, relatamos dois casos de trombose induzida pelo calor endovenoso que teriam indicação de heparina de baixo peso molecular até a resolução do quadro. Porém, optou-se pelo uso da rivaroxabana (15 mg de 12 em 12h), com resolução completa do trombo em 4 semanas (caso 1) e em 7 dias (caso 2). A rivaroxabana pode ser uma alternativa promissora no tratamento da trombose induzida pelo calor endovenoso avançada, pela simplicidade da posologia, sem comprometimento da eficácia ou da segurança. São necessários estudos prospectivos, randomizados e controlados que possibilitem melhor entendimento da condição e o desenvolvimento de recomendações mais definitivas sobre opções de prevenção e tratamento.

Tão perto de casa, tão longe de nós: etnografia das novas margens no centro da urbe

PubMed Central

Fernandes, Por Luís

2011-01-01

Philippe Bourgois é, desde 2007, “Richard Perry University professor” no Departamento de Antropologia e de Medicina Familiar e de Práticas Comunitárias na Universidade da Pensilvânia. Esteve durante largos anos ligado ao Departamento de Antropologia, História e Medicina Social da Universidade da Califórnia, São Francisco. A publicação, em 1995, de In Search of Respect: Selling Crack in El Barrio1 projectaria o seu nome muito para além dos Estados Unidos: uma etnografia no coração porto-riquenho do Harlem, em torno dos actores e dos ambientes da venda de crack. Seguir-se-ia um longo trabalho de terreno em acampamentos de dependentes de heroína em São Francisco, orientando o seu trabalho para as formas mais radicais da pobreza e da marginalidade nos EUA. É deste trabalho de terreno que sai o seu último livro, Righteous Dopefiend2. Em Junho de 2007 esteve em Lisboa para participar na 3.a edição do “Ethnografeast”. Foi então que aproveitámos a oportunidade para ouvir um percurso invulgar contado pelo próprio: uma longa conversa no Hotel Zurique, cujo nome só vem ao caso por evocar o país onde passou uma parte da infância. PMID:22013286

VizieR Online Data Catalog: Equivalent width of 21 RR Lyrae stars (Pancino+, 2015)

NASA Astrophysics Data System (ADS)

Pancino, E.; Britavskiy, N.; Romano, D.; Cacciari, C.; Mucciarelli, A.; Clementini, G.

2015-02-01

Equivalent widths and atomic data of the absorption lines used in the abundance analysis, for each separate exposure at different phases. Observations of 15 RR Lyrae stars (DR And, X Ari, TW Boo, RZ Cam, RX Cet, U Com, RV CrB, SW CVn, UZ CVn, AE Dra, SZ Gem, VX Her, DH Hya, TU UMa, and RV UMa) and one BL Her star (UY Eri) were carried out with SARG@TNG, operated on the island of La Palma, Spain, during two separate runs in 2009 March and between September and November. Eight stars (SW Aqr, TW Cap, DH Hya, V Ind, SS Leo, V716 Oph, BK Tuc, and UV Vir) were observed with UVES@VLT, between 2009 April and August in service mode. (3 data files).

The minimum mass ratio of W Ursae Majoris binaries

NASA Technical Reports Server (NTRS)

Rasio, Frederic A.

1995-01-01

The minimum mass ratio for tidal stability of a contact binary containing two unevolved main-sequence stars is calculated to be q(sub min) approximately =0.09 in the case of a mostly radiative primary, and it is higher if an appreciable fraction of the mass lies in a convective envelope. At least one observed system, AW UMa, has a mass ratio just below this value (q = 0.075), implying that, if the system is stable, the primary must be slightly evolved and must have a very shallow convective envelope. Contact binaries with mass ratios significantly below that of AW UMa should not be observed, since they are tidally unstable and quickly merge into a single, rapidly rotating object, on a timescale approximately 10(exp 3)-10(exp 4) yr.

Buckets of ash track tephra flux from Halema'uma'u Crater, Hawai'i

USGS Publications Warehouse

Swanson, Don; Wooten, Kelly M.; Orr, Tim R.

2009-01-01

The 2008–2009 eruption at Kīlauea Volcano's summit made news because of its eight small discrete explosive eruptions and noxious volcanic smog (vog) created from outgassing sulfur dioxide. Less appreciated is the ongoing, weak, but continuous output of tephra, primarily ash, from the new open vent in Halema'uma'u Crater. This tephra holds clues to processes causing the eruption and forming the new crater-in-a-crater, and its flux is important to hazard evaluations.The setting of the vent–easily accessible from the Hawaiian Volcano Observatory (HVO)—is unusually favorable for neardaily tracking of tephra mass flux during this small prolonged basaltic eruption. Recognizing this, scientists from HVO are collecting ash and documenting how ejection masses, components, and chemical compositions vary through time.

Misfit dislocation patterns of Mg-Nb interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Youxing; Shao, Shuai; Liu, Xiang-Yang

The role of heterogeneous interfaces in improving mechanical properties of polycrystalline aggregates and laminated composites has been well recognized with interface structure being of fundamental importance in designing composites containing multiple interfaces. In this paper, taking the Mg (hexagonal close-packed (hcp))/Nb (body-centered cubic (bcc)) interface as an example, we develop Mg-Nb interatomic potentials for predicting atomic configurations of Mg/Nb interfaces. We systematically characterize interface dislocations of Mg/Nb interfaces with Nishiyama-Wassermann (NW) and Kurdjumov-Sachs (KS) orientation relationships and propose a generalized procedure of characterizing interface structure by combining atomistic simulation and interface dislocation theory, which is applicable for not only hcp/bccmore » interfaces, but also other systems with complicated interface dislocation configurations.Here, in Mg/Nb, interface dislocation networks of two types of interfaces are significantly different although they originate from partial dislocations of similar character: the NW interface is composed of three sets of partial dislocations, while the KS interface is composed of four sets of interface dislocations - three sets of partial dislocations and one set of full dislocations that forms from the reaction of two close partial dislocations.« less

Uma análise do fenômeno “alternância de línguas” na fala de bilíngues intermodais (Libras e Português)

PubMed Central

de Sousa, Aline Nunes; de Quadros, Ronice Müller

2013-01-01

Um interessante fenômeno lingüístico presente nas interações das pessoas bilíngues é a alternância de línguas. Neste trabalho, estamos investigando a alternância entre a língua portuguesa oral e a língua de sinais brasileira – Libras, numa mesma cadeia enunciativa, com o objetivo de identificar e analisar o uso dessa alternância na fala de uma criança e de um adulto (ambos ouvintes, filhos de pais surdos), interagindo em uma situação de bilinguismo intermodal, com interlocutores surdos e ouvintes. A alternância de línguas, nesse caso, ocorre quando se para de falar em português e se alterna para sinalizar. O presente trabalho se caracteriza como um estudo inicial, com análise qualitativa de dados. Fazem parte do nosso corpus nove sessões de interações em Libras e em português oral, gravadas em vídeo, que fazem parte do Projeto Desenvolvimento Bilíngue Bimodal da UFSC. Os dados revelam que as características da alternância de línguas pelo adulto e pela criança parecem ter semelhanças e diferenças. O sujeito adulto parece ter feito um uso da alternância mais preocupado com o curso da interação. A criança, por sua vez, não parece tê-la usado com propósitos pragmáticos específicos. Quanto à extensão das alternâncias, pode-se perceber que tanto a criança quanto o adulto utilizaram enunciados maiores do que uma única palavra isolada. O papel dos interlocutores parece ter sido decisivo nas interações aqui investigadas – especialmente nas do adulto, já que a criança ainda está em processo de tomada de consciência do papel do interlocutor na interação. PMID:24379831

Camões e a cosmogonia

NASA Astrophysics Data System (ADS)

Costa, J. M.

2003-08-01

Os Lusíadas, escrito por Luis de Camões em 1572, é um poema épico renascentista e a visão Cosmogônica do autor é apresentada, principalmente, no último canto do poema, quando Tétis mostra ao Gama a Máquina do Mundo. A Cosmogonia de Camões neste poema reflete uma visão de uma época de transição, que ainda não incorporou os elementos da revolução Copernicana. É uma visão Grego- Ptolomaica e também medieval. O poeta guia-se pela tradução e notas feita por Pedro Nunes, inventor do Nonio, do Tratado da Esfera "De Sphaera" do Astrônomo Inglês John Holywood, mais conhecido pelo nome latinizado de Johannes Sacrobosco. Outra provável fonte de Camões, de acordo com Luciano Antonio Pereira da Silva em Astronomia de os Lusíadas, é o "Theoricae novae Planetarum" (1460) do astrólogo Alemão Jorge Purbáquio (1423 - 1461). A Astronomia de Os Lusíadas representa a ciência do tempo de Camões. Camões nunca emprega a palavra constelação e seu catálogo é bastante completo. A Máquina do Mundo tem a Terra no centro. Em redor, em círculos concêntricos, a lua (Diana), Mercúrio, Vênus, o Sol (Febo), Marte, Júpiter e Saturno. Envolvendo estes astros tem o firmamento seguido pelo "Céu Áqueo" ou cristalino, depois o 1o Móbil, esfera que arrasta todas as outras consigo. Este trabalho, multidisciplinar, serve tanto para ensinar aos alunos da Física como das Ciências Humanas, a concepção de mundo do renascimento de uma forma belamente poética em versos decassílabos Este trabalho também ajuda na apreciação do maior clássico da língua portuguesa e mostra como as Ciências e as artes, em geral, estão correlacionadas e refletem a visão de mundo da época em que foi produzida.

Propriedades de estruturas temporais rápidas submilimétricas durante uma grande explosão solar

NASA Astrophysics Data System (ADS)

Raulin, J.-P.; Kaufmann, P.; Gimenez de Castro, C. G.; Pacini, A. A.; Makhmutov, V.; Levato, H.; Rovira, M.

2003-08-01

Apresentamos novas propriedades de variações rápidas da emissão submilimétrica durante uma das maiores explosões solares do ciclo solar 23. Os dados analisados neste estudo foram obtidos com o Telescópio Solar Submilimétrico (SST), que observa o Sol em 212 GHz e 405 GHz, e comparados com emissões em Raios-X duros e Raios-gama (fótons de energia > 10 MeV), que foram obtidas pelo experimento GRS do Yohkoh. Aplicamos diferentes metodologias para detectar e caracterizar, ao longo do evento, os pulsos submilimétricos (duração de 50-300 ms) detectados acima de uma componente mais lenta (alguns minutos). Os resultados mostram que durante a fase impulsiva, num instante próximo ao tempo do máximo do evento, houve um aumento da ocorrência de maiores e de mais rápidas estruturas temporais. Também identificamos uma boa correlação com as emissões em raios-X e raios-gama (até a faixa de energia 10-100 MeV), indicando que os pulsos rápidos submilimétricos refletiram injeções primárias de energia durante o evento.O espectro do fluxo desses pulsos é crescente com a freqüência entre 212 and 405 GHz, na maioria dos casos, ao contrário do observado para a componente gradual. As posições calculadas para as estruturas rápidas são discretas, compactas e localizadas em toda a área da região ativa, o que é previsto nos modelos de explosões solares decorrentes de instabilidades múltiplas em diferentes pequenas regiões. Por outro lado, a posição calculada para a componente lenta é estável durante a fase impulsiva. Assim, a comparação entre as características do espectro de fluxo e da localização da emissão, para os pulsos rápidos e para a componente gradual, sugere que as respectivas emissões são de natureza diferente.

Studies on magnetocaloric and magnetic coupling effects =

NASA Astrophysics Data System (ADS)

Amaral, Joao Cunha de Sequeira

O presente trabalho apresenta novas metodologias desenvolvidas para a analise das propriedades magneticas e magnetocaloricas de materiais, sustentadas em consideracoes teoricas a partir de modelos, nomeadamente a teoria de transicoes de fase de Landau, o modelo de campo medio molecular e a teoria de fenomeno critico. Sao propostos novos metodos de escala, permitindo a interpretacao de dados de magnetizacao de materiais numa perspectiva de campo medio molecular ou teoria de fenomeno critico. E apresentado um metodo de estimar a magnetizacao espontanea de um material ferromagnetico a partir de relacoes entropia/magnetizacao estabelecidas pelo modelo de campo medio molecular. A termodinamica das transicoes de fase magneticas de primeira ordem e estudada usando a teoria de Landau e de campo medio molecular (modelo de Bean-Rodbell), avaliando os efeitos de fenomenos fora de equilibrio e de condicoes de mistura de fase em estimativas do efeito magnetocalorico a partir de medidas magneticas. Efeitos de desordem, interpretados como uma distribuicao na interaccao magnetica entre ioes, estabelecem os efeitos de distribuicoes quimicas/estruturais nas propriedades magneticas e magnetocaloricas de materiais com transicoes de fase de segunda e de primeira ordem. O uso das metodologias apresentadas na interpretacao das propriedades magneticas de variados materiais ferromagneticos permitiu obter: 1) uma analise quantitativa da variacao de spin por iao Gadolinio devido a transicao estrutural do composto Gd5Si2Ge2, 2) a descricao da configuracao de cluster magnetico de ioes Mn na fase ferromagnetica em manganites da familia La-Sr e La-Ca, 3) a determinacao dos expoentes criticos β e δ do Niquel por metodos de escala, 4) a descricao do efeito da pressao nas propriedades magneticas e magnetocaloricas do composto LaFe11.5Si1.5 atraves do modelo de Bean-Rodbell, 5) uma estimativa da desordem em manganites ferromagneticas com transicoes de segunda e primeira ordem, 6) uma descricao de campo medio das propriedades magneticas da liga Fe23Cu77, 7) o estudo de efeitos de separacao de fase na familia de compostos La0.70-xErxSr0.30MnO3 e 8) a determinacao realista da variacao de entropia magnetica na familia de compostos de efeito magnetocalorico colossal Mn1-x-yFexCryAs.

Prevendo a atividade solar através de redes neurais nebulosas

NASA Astrophysics Data System (ADS)

Martin, V. A. F.; Poppe, P. C. R.

2003-08-01

Atualmente, a integração de redes neurais com técnicas da Matemática Nebulosa (Fuzzy Sets), tem sido usada robustamente para fazer previsões em vários sistemas físicos. Este trabalho representa uma continuidade da contribuição apresentada anteriormente durante a XXVIIa Reunião Anual da SAB, onde exploramos a aplicação de redes neurais para previsões futuras de séries temporais. Para este, enfatizamos o uso da técnica ANFIS (Adaptative Neuro-Fuzzy Inference System), que consiste em uma rede do tipo back-propagation, onde os dados são processados em uma camada intermediária, tendo numa camada de saída, os dados numéricos. Para que a previsão seja feita com sucesso utilizando-se técnicas matemáticas adequadas, é fundamental a existência de uma série razoavelmente longa de modo que a dinâmica contida nesta possa ser melhor extraída pela rede neural. Nesse sentido, foram utilizados novamente os dados históricos das manchas do Sol (1818-2002) afim de verificar o comportamento futuro da atividade solar (Ciclos de Schawbe) a partir da técnica descrita acima. Previsões realizadas para o ciclo anterior (n.22, máximo de 158,5 em julho de 1989), bem como para o atual (n.23, máximo de 153 em setembro de 2000), apontam valores bastante coerentes com os publicados na literatura, levando em consideração, respectivamente, as barras de erros associadas: 166+/-18 e 160+/-14. Para o próximo ciclo de Schawbe (2006-2017), nossa previsão aponta o valor de 172+/-23 como máximo para o primeiro semestre de 2011 (Abril +/- 3 meses). A ANFIS acompanha de maneira satisfatória o movimento das séries estudadas durante o treinamento e durante a verificação (menor dispersão das funções de pertinência), com erro absoluto inferior a 20 por cento.

Telemedicine: challenges to dissemination in Brazil.

PubMed

Maldonado, Jose Manuel Santos de Varge; Marques, Alexandre Barbosa; Cruz, Antonio

2016-11-03

Telemedicine has been seen as an important tool for facing the challenges of universal health systems. The goal of this article is to discuss the main challenges to its full dissemination in Brazil. Being a somewhat new area, there are not many scientific papers that systematize it. This article is an exploratory paper, as it aims to provide an overall perspective on the subject. From an economic point of view, telemedicine is a strategic area due to its an intrinsic potential of being a source for generating innovation, for requiring and incorporating technological breakthroughs from other areas, and for its interdisciplinary nature and dynamic inter-relations that drive different industries. From the social perspective, it has the potential to make access to health services democratic, by connecting remote regions with health services located in hospitals and centers of reference for prevention, diagnosis and treatment. Resumo: A telemedicina está sendo vista como uma ferramenta importante para enfrentar os desafios dos sistemas de saúde universais. O objetivo deste artigo foi discutir os principais desafios para a sua plena disseminação no Brasil. Em função do caráter relativamente emergente desta área, existe uma escassez relativa de trabalhos científicos que a sistematizem. Por isso, este artigo se enquadra na categoria de trabalho exploratório, já que tem por objetivo proporcionar uma visão geral sobre o tema. Destaca-se, que do ponto de vista econômico, a telemedicina se constitui em uma área estratégica por seu potencial intrínseco de ser fonte geradora de inovações, por demandar e incorporar avanços tecnológicos oriundos de outras áreas e, em função da sua natureza interdisciplinar e de suas inter-relações dinâmicas, pela possibilidade de impulsionar diferentes indústrias. Do ponto de vista social, tem o potencial de democratizar o acesso aos serviços de saúde, integrando regiões remotas com serviços de saúde localizados em hospitais e centros de referência no que se refere à prevenção, diagnóstico e tratamento.

Análise sobre o Conhecimento de um Grupo de Alunos do Ensino Médio da Rede Estadual de São Paulo sobre Termos e Fenômenos Astronômicos do Cotidiano

NASA Astrophysics Data System (ADS)

de Oliveira, E. F.; Voelzke, M. R.; Amaral, L. H.

2007-08-01

Embora os Parâmetros Curriculares Nacionais do Ensino Médio (PCN-EM) e as orientações complementares a esses Parâmetros (PCN+) apontem a importância de uma abordagem significativa de conceitos relacionados à astronomia nas aulas de Física, muitos estudantes terminam o Ensino Médio (EM) sem compreender a razão de certos acontecimentos de origem celeste, ainda que estes façam parte de seu cotidiano. Este trabalho tem por objetivo analisar os conhecimentos básicos em astronomia dos alunos de EM da escola estadual Batista Renzi, bem como investigar os meios através dos quais estes conhecimentos foram adquiridos. Para tanto foi elaborado um questionário de múltipla escolha aplicado a 310 alunos distribuídos entre as três séries do EM dos períodos matutino e noturno. Dessa forma, observou-se que apenas 34,5% relacionaram as estações do ano à inclinação do eixo de rotação da Terra, 21,3% indicaram a influência gravitacional da Lua e do Sol como responsáveis pelo fenômeno das marés, 24,5% indicaram corretamente quais são os objetos celestes mais próximos da Terra, 36,1% identificaram ano-luz como uma medida de distância e 34,2% reconheceram uma estrela cadente como meteoro. Em contrapartida, 67,1% compreendiam a sucessão entre dia e noite, 73,9% identificaram o Sol como estrela e 52,3% relacionaram o Big Bang à origem do Universo. Além disso, foram comparadas as respostas de alunos de diferentes séries e períodos, observando-se, dentre outras coisas, que os estudantes do terceiro ano apresentam um percentual de acertos semelhante ao dos alunos do primeiro, caracterizando que a abordagem de tópicos relacionados à astronomia no EM não tem contribuído para uma maior compreensão dos fenômenos e conceitos.

Survey infravermelho do braço espiral de scuttum e da barra no centro galáctico

NASA Astrophysics Data System (ADS)

Amôres, E. B.; Lépine, J. R. D.

2003-08-01

O survey infravermelho consiste de observações utilizando a CAMIV no telescópio de 60 cm do LNA. Nosso principal objetivo é melhor caracterizar a população estelar dos braços espirais e de uma estrutura existente no centro galáctico que acreditamos ser devido à existência de uma barra, cujas extremidades estariam localizadas em longitudes galácticas l~23° e l~14°. As observações realizadas em vários filtros (imagens J, H e K) são particularmente importantes nas direções que tangenciam os braços espirais, desta forma, comparamos uma direção que atravessa um braço a uma direção próxima que não passa pelo braço, sendo que ambas possuem a mesma contribuição de contagens foreground. Nas missões realizadas até o presente, observamos a região na direção tangencial ao braço de Scuttum, com observações de l = 30.04° até l = 31.04°, a cada intervalo de longitude de 0.1°, para latitude galáctica de 0.0°, 0.25°, 0.50°. Para as regiões que acreditamos serem as extremidades da barra, observamos as faixas de longitude compreendidas entre -15° £ l £ -13° e 24° £ l £ 22° a cada intervalo de 0.25°, para latitude galáctica de 0.0° e 0.25°. As observações nos filtros J e H foram feitas com tempo de integração de 60s, na banda K, as observações foram feitas utilizando o filtro C1 com tempo de integração de aproximadamente 210 s (12x15s). Elaboramos diagramas cor-cor e cor-magnitude onde podemos verificar a existência de regiões com diferentes contagens e população estelar à medida que um braço espiral é atravessado.

Technique for converting non-conforming hexahedral-to-hexahedral interfaces into conforming interfaces

DOEpatents

Staten, Matthew L.; Shepherd, Jason F.; Ledoux, Frank; Shimada, Kenji; Merkley, Karl G.; Carbonera, Carlos

2013-03-05

A technique for conforming an interface between a first mesh and a second mesh is disclosed. A first interface surface in the first mesh and a second interface surface in the second mesh residing along the interface are identified. The first and second interface surfaces are initially non-conforming along the interface. Chords within the first and second interface surfaces that fall within a threshold separation distance of each other are paired. Sheets having chords that reside within the first or second interface surfaces are recursively inserted into or extracted from one or both of the first and second meshes until all remaining chords within the first interface surface are paired with corresponding chords in the second interface surface and all remaining chords within the second interface surface are paired with corresponding chords in the first interface surface.

Method and apparatus for connecting finite element meshes and performing simulations therewith

DOEpatents

Dohrmann, Clark R.; Key, Samuel W.; Heinstein, Martin W.

2003-05-06

The present invention provides a method of connecting dissimilar finite element meshes. A first mesh, designated the master mesh, and a second mesh, designated the slave mesh, each have interface surfaces proximal the other. Each interface surface has a corresponding interface mesh comprising a plurality of interface nodes. Each slave interface node is assigned new coordinates locating the interface node on the interface surface of the master mesh. The slave interface surface is further redefined to be the projection of the slave interface mesh onto the master interface surface.

Tratamento endovascular de aneurisma de tronco braquiocefálico em paciente com síndrome de Ehlers-Danlos tipo IV

PubMed Central

Belczak, Sergio Quilici; Klajner, Rafael Kogan; Ogawa, Lara Cote; Lucato, Laís Leite; Zeque, Bruna Stecca; de Macedo, Felipe Basso; da Silva, Ingredy Tavares; Atihe, Luís Felipe

2016-01-01

Resumo A síndrome de Ehlers-Danlos é uma doença genética que acarreta alteração na síntese de colágeno, causando extrema fragilidade do tecido conjuntivo. Tal fragilidade predispõe a uma série de doenças vasculares, como dissecções, aneurismas e pseudoaneurismas. Os autores relatam o histórico de um indivíduo de 19 anos com aneurisma de tronco braquiocefálico que foi submetido ao tratamento endovascular com implante de stents revestidos. O caso evoluiu com complicação do sítio de punção, que também foi tratada em caráter de emergência pela técnica endovascular com o implante de stent revestido.

A 60-NIGHT Campaign on Dwarf Novae - Part One - Photometric Variability of Su-Ursae and Yz-Cancri

NASA Astrophysics Data System (ADS)

van Paradijs, J.; Charles, P. A.; Harlaftis, E. T.; Arevalo, M. J.; Baruch, J. E. F.; Callanan, P. J.; Casares, J.; Dhillon, V. S.; Gimenez, A.; Gonzalez, R.; Matinez-Pais, I. G.; Jones, D. H. P.; Hassall, B. J. M.; Hellier, C.; Kidger, M. R.; Lazaro, C.; Marsh, T. R.; Mason, K. O.; Mukai, K.; Naylor, T.; Reglero, V.; Rutten, R. G. M.; Smith, R. C.

1994-04-01

A 60-night campaign on SU UMa, YZ Cnc and some secondary targets was carried out during 1988 December and 1989 January at the Observatorio del Roque de Los Muchachos (the 1988 International Time Project). The aim was to study the behaviour of these dwarf novae through their outburst cycle. Here we present the overall light curves of the main targets, SU UMa and YZ Cnc, which show that the optical fluxes continue to decrease after the end of the outburst. For YZ Cnc we find that, during quiescence, orbital variability is present, which may be interpreted as modulation caused by the bright-spot region. Near the end of an outburst, a weak, sinusoidal variation is observed; we discuss the possibility that this arises either from the secondary star or the accretion disc.

Absolute and geometric parameters of contact binary GW Cnc

NASA Astrophysics Data System (ADS)

Gürol, B.; Gökay, G.; Saral, G.; Gürsoytrak, S. H.; Cerit, S.; Terzioğlu, Z.

2016-07-01

We present the results of our investigation on the geometrical and physical parameters of the W UMa type binary system GW Cnc. We analyzed the photometric data obtained in 2010 and 2011 at Ankara University Observatory (AUO) and the spectroscopic data obtained in 2010 at TUBITAK National Observatory (TUG) by using the Wilson-Devinney (2013 revision) code to obtain the absolute and geometrical parameters. We derived masses and radii of the eclipsing system to be M1 = 0.257M⊙ , M2 = 0.971M⊙ , R1 = 0.526R⊙ and R2 = 0.961R⊙ with an orbital inclination i(∘) = 83.38 ± 0.25 and we determined the GW Cnc system to be a W-type W UMa over-contact binary with a mass ratio of q = 3.773 ± 0.007 .

Surgical correction of ectopic penis and scrotum associated with bilateral orchidopexy.

PubMed

Sobral, Daniel Santos Rocha; Silva, Helder Damásio da; Damázio, Eulálio

2017-01-01

Ectopic penis is usually associated with penoscrotal transposition, and it is rarely observed in isolation. We report a surgical approach for an extremely rare case. A 10-year-old male patient with bilateral cryptorchidism and ectopic penis and scrotum in perineal area, with no penoscrotal transposition, representing an association not yet described in literature. A previous orchiopexy failed due to ectopic scrotum. By means of an inverted Y incision, the penis was mobilized and a perineal skin flap in form of a testicular sac was prepared. Finally orchiopexy was performed. The surgery was essential to treat cryptorchidism and to improve the self-image of the patient. RESUMO O pênis ectópico geralmente ocorre associado à transposição peno-escrotal, sendo raro isoladamente. Relatamos uma abordagem cirúrgica para um caso extremamente raro. Tratava-se de paciente do sexo masculino, 10 anos, com criptorquidia bilateral e pênis e escroto ectópicos, na região perineal, sem transposição peno-escrotal, representando uma associação ainda não descrita na literatura. Orquidopexia prévia sem sucesso, devido à ectopia do escroto. Por meio de uma incisão em Y invertido, mobilizou-se o pênis e preparou-se um retalho da pele perineal em forma de bolsa testicular. Por fim, realizou-se a orquidopexia. A cirurgia foi fundamental para tratar a criptorquidia e promover ganho na autoimagem do paciente.

Shallow outgassing changes disrupt steady lava lake activity, Kilauea Volcano

NASA Astrophysics Data System (ADS)

Patrick, M. R.; Orr, T. R.; Swanson, D. A.; Lev, E.

2015-12-01

Persistent lava lakes are a testament to sustained magma supply and outgassing in basaltic systems, and the surface activity of lava lakes has been used to infer processes in the underlying magmatic system. At Kilauea Volcano, Hawai`i, the lava lake in Halema`uma`u Crater has been closely studied for several years with webcam imagery, geophysical, petrological and gas emission techniques. The lava lake in Halema`uma`u is now the second largest on Earth, and provides an unprecedented opportunity for detailed observations of lava lake outgassing processes. We observe that steady activity is characterized by continuous southward motion of the lake's surface and slow changes in lava level, seismic tremor and gas emissions. This normal, steady activity can be abruptly interrupted by the appearance of spattering - sometimes triggered by rockfalls - on the lake surface, which abruptly shifts the lake surface motion, lava level and gas emissions to a more variable, unstable regime. The lake commonly alternates between this a) normal, steady activity and b) unstable behavior several times per day. The spattering represents outgassing of shallowly accumulated gas in the lake. Therefore, although steady lava lake behavior at Halema`uma`u may be deeply driven by upwelling of magma, we argue that the sporadic interruptions to this behavior are the result of shallow processes occurring near the lake surface. These observations provide a cautionary note that some lava lake behavior is not representative of deep-seated processes. This behavior also highlights the complex and dynamic nature of lava lake activity.

The Spot Variability and Related Brightness variations of the Solar Type PreContact W UMa Binary System V1001 Cas

NASA Astrophysics Data System (ADS)

Samec, Ronald George; Koenke, Sam S.; Faulkner, Danny R.

2015-08-01

A new classification of eclipsing binary has emerged, Pre Contact WUMa Binaries (PCWB’s, Samec et al. 2012). These solar-type systems are usually detached or semidetached with one or both components under filling their critical Roche lobes. They usually have EA or EB-type light curves (unequal eclipse depths, indicating components with substantially different temperatures). The accepted scenario for these W UMa binaries is that they are undergoing steady but slow angular momentum losses due to magnetic braking as stellar winds blow radially away on stiff bipolar field lines. These binaries are believed to come into stable contact and eventually coalesce into blue straggler type, single, fast rotating A-type stars (Guinan and Bradstreet,1988). High precision 2012 and 2009 light curves are compared for the very short period (~0.43d) Precontact W UMa Binary (PCWB), V1001 Cassiopeia. This is the shortest period PCWB found so far. Its short period, similar to the majority of W UMa’s, in contrast to its distinct Algol-type light curve, make it a very rare and interesting system. Our solutions of light curves separated by some three years give approximately the same physical parameters. However the spots radically change, in temperature, area and position causing a distinctive variation in the shape of the light curves. We conclude that spots are very active on this solar type dwarf system and that it may mimic its larger cousins, the RS CVn binaries.

Propriedades físicas de condensações densas no Escorpião

NASA Astrophysics Data System (ADS)

Vilas-Boas, J. W. S.; Barbosa, P. R., Jr.; Hickel, G. R.

2003-08-01

O conhecimento das propriedade físicas das condensações das nuvens escuras e sua relação com a dinâmica das núvens é um dos caminhos para o entendimento dos mecanismos de formação de estrelas de massas pequenas. Nesse trabalho, 8 condensações da nuvem escura do Escorpião foram observadas através de transições das moléculas de 13CO, C18O e NH3, utilizando-se os radiotelescopios de 15 m do SEST e 64 m de PARKES. Embora localizadas na superfície de uma bolha com velocidade de expansão entre 12 km/s e 15 km/s (Vilas-Boas et al), as linhas de monóxido de carbono apresentaram características típicas daquelas observadas em nuvens escuras. Em apenas uma condensação, contendo um objeto Pre-Sequência Principal (PMS), foi detectada emissão da molécula de amônia. A comparação direta entre as propriedades dessas condensações densas (núcleos) e aquelas identificadas na Musca, que se caracteriza por ser uma núvem de baixa atividade de formação estelar, mostra que elas têm propriedades idênticas e que as eficiências de formação estelar nos núcleos de ambas as nuvens são similares.

The Orbital Period of the SU Ursae Majoris Star EK Trianguli Australis and Evidence for Ring-Like Accretion Disks in Long-Supercycle Length SU Ursae Majoris Stars

NASA Astrophysics Data System (ADS)

Mennickent, Ronald E.; Arenas, Jose

1998-06-01

An orbital period of 0.06288(5) d has been found from a radial velocity study of the Hα emission line. In addition, we have detected an extra line emitting source located ~ 80(deg) apart from the vector joining the secondary--primary centers, as measured in the opposite sense to the binary rotational motion. This is not the expected location for the hotspot in dwarf novae. This anomaly could be removed by assuming a line emission lagging behind the white dwarf binary motion. In addition, we have estimated line emissivity (~ r(-alpha ) ) and disk radius (R equiv r_in/r_out) for 8 SU UMa stars. Most stars fit alpha = 1.8 +/- 0.1 but AK Cnc and WZ Sge strongly deviate from the mean; their emission line shapes can be explained assuming a post-outburst accretion disk mostly emitting close to the white dwarf (AK Cnc) and a ring-like disk (WZ Sge). In addition, we have found a tendency of long-supercycle length SU UMa stars to show very compact (large R; probably ring-like) accretion disks. If the supercycle length were basically controlled by the mass transfer rate (dot {M}), the inner disk radius would be a function of dot {M}. A white dwarf magnetic field ~ 5000 G is required to fit the truncation radius with the magnetosphere radius of SU UMa stars.

On acoplamento mecânico entre a antena e o transdutor no detector de ondas gravitacionais Mario Schenberg

NASA Astrophysics Data System (ADS)

Melo, J. L.; Aguiar, O. D.; Velloso, W. F., Jr.; Lucena, A. U.

2003-08-01

O detector de ondas gravitacionais MARIO SCHENBERG consistirá de uma massa esférica de cobre-alumínio de 1150kg resfriada a 4K, sobre a qual serão instalados 6 transdutores de nióbio. Com estes trandutores pretende-se converter um possível sinal de onda gravitacional detectado em sinal elétrico, para tanto é necessário que o acoplamento mecânico entre os transdutores e a massa ressonante seja o maior possível. Isto significa que o transdutor deve ser ressonante na mesma freqüência que a antena (aproximadamente 3200Hz). Neste trabalho foi desenvolvida uma geometria para a estrutura mecânica do trandutor. Isto foi feito criando-se modelos em elementos finitos usando-se o "software" MSC/Nastran. Estes modelos criados foram analisados estaticamente (cálculo de tensões) e dinamicamente (cálculo das freqüências de ressonâncias e seus respectivos modos normais) de maneira a se obter o primeiro modo normal do transdutor em 3200Hz. A partir destes cálculos escolheu-se a melhor geometria para o transdutor. Os próximos passos do trabalho serão: usinar este transdutor em uma barra de nióbio e testá-lo à temperatura ambiente e à baixa temperatura. Após isto, pretende-se testá-lo na própria antena resfriada.

Interface Management for a NASA Flight Project Using Model-Based Systems Engineering (MBSE)

NASA Technical Reports Server (NTRS)

Vipavetz, Kevin; Shull, Thomas A.; Infeld, Samatha; Price, Jim

2016-01-01

The goal of interface management is to identify, define, control, and verify interfaces; ensure compatibility; provide an efficient system development; be on time and within budget; while meeting stakeholder requirements. This paper will present a successful seven-step approach to interface management used in several NASA flight projects. The seven-step approach using Model Based Systems Engineering will be illustrated by interface examples from the Materials International Space Station Experiment-X (MISSE-X) project. The MISSE-X was being developed as an International Space Station (ISS) external platform for space environmental studies, designed to advance the technology readiness of materials and devices critical for future space exploration. Emphasis will be given to best practices covering key areas such as interface definition, writing good interface requirements, utilizing interface working groups, developing and controlling interface documents, handling interface agreements, the use of shadow documents, the importance of interface requirement ownership, interface verification, and product transition.

Are Pretty Interfaces Worth the Time? The Effects of User Interface Types on Web-Based Instruction

ERIC Educational Resources Information Center

Cheon, Jongpil; Grant, Michael M.

2009-01-01

The purpose of this study was to examine the effectiveness of three different interface types on Web-based instruction: a text-based interface, a graphical interface and a metaphorical interface. In order to determine differences among three interface groups, we compared learning performance, cognitive load, usability, and appeal with various data…

AMMO-Prot: amine system project 3D-model finder.

PubMed

Navas-Delgado, Ismael; Montañez, Raúl; Pino-Angeles, Almudena; Moya-García, Aurelio A; Urdiales, José Luis; Sánchez-Jiménez, Francisca; Aldana-Montes, José F

2008-04-25

Amines are biogenic amino acid derivatives, which play pleiotropic and very important yet complex roles in animal physiology. For many other relevant biomolecules, biochemical and molecular data are being accumulated, which need to be integrated in order to be effective in the advance of biological knowledge in the field. For this purpose, a multidisciplinary group has started an ontology-based system named the Amine System Project (ASP) for which amine-related information is the validation bench. In this paper, we describe the Ontology-Based Mediator developed in the Amine System Project (http://asp.uma.es) using the infrastructure of Semantic Directories, and how this system has been used to solve a case related to amine metabolism-related protein structures. This infrastructure is used to publish and manage not only ontologies and their relationships, but also metadata relating to the resources committed with the ontologies. The system developed is available at http://asp.uma.es/WebMediator.

Observations and light curve solutions of a selection of shallow-contact W UMa binaries

NASA Astrophysics Data System (ADS)

Kjurkchieva, Diana P.; Popov, Velimir A.; Vasileva, Doroteya L.; Petrov, Nikola I.

2018-07-01

Photometric observations in Sloan g‧ and i‧ bands of the W UMa binaries V0951 Per, CSS J062803.2+571604, CSS J222157.2+275308, CSS J075135.6+382028, V0338 Dra, NSVS 2256852, NSVS 4666412, V1355 Tau, NSVS 4808227, NSVS 4726498, CSS J075350.1+264830 and HL Lyn are presented. The light curve solutions revealed that these binaries have overcontact configurations with small fillout factors (within 0.1-0.2). Seven of them undergo total eclipses and their photometric mass ratios should be accepted with confidence. The temperature differences of the components of CSS J062803.2+571604 and NSVS 2256852 exceed 1100 K which is unusual for overcontact binaries. We suspect that NSVS 2256852 is a probable candidate for merger due to its small mass ratio of q = 0.16 and to the registered decreasing of the orbital period.

Observations and light curve solutions of three ultrashort-period W UMa binaries

NASA Astrophysics Data System (ADS)

Kjurkchieva, Diana P.; Michel, Raul; Popov, Velimir A.; Deras, Dan

2018-07-01

Photometric observations in V, Rc and Ic bands of the ultrashort-period W UMa binaries 1SWASP J044132.96+440613.7, 1SWASP J052926.88+461147.5 and NSVS 2175434 are presented. The results from the modeling and analysis of our observations reveal that: (i) All targets undergo total eclipses and their photometric mass ratios should be accepted with confidence; (ii) All stellar components are late-type dwarfs; (iii) The temperature difference of target components does not exceed 150 K; (iv) All targets have overcontact configurations with fill-out factor around 0.24; (v) The orbit of NSVS 2175434 is slightly eccentric which is unusual for such an ultrashort-period binary; (vi) The orbital periods of all targets were improved. Masses, radii and luminosities of the stellar components were estimated by the empirical relation "period, orbital axis" for short- and ultrashort-period binaries.

The optical emission from oscillating white dwarf radiative shock waves

NASA Technical Reports Server (NTRS)

Imamura, James N.; Rashed, Hussain; Wolff, Michael T.

1991-01-01

The hypothesis that quasi-periodic oscillations (QPOs) are due to the oscillatory instability of radiative shock waves discovered by Langer et al. (1981, 1092) is examined. The time-dependent optical spectra of oscillating radiative shocks produced by flows onto magnetic white dwarfs are calculated. The results are compared with the observations of the AM Her QPO sources V834 Cen, AN UMa, EF Eri, and VV Pup. It is found that the shock oscillation model has difficulties with aspects of the observations for each of the sources. For VV Pup, AN UMa, and V834 Cen, the cyclotron luminosities for the observed magnetic fields of these systems, based on our calculations, are large. The strong cyclotron emission probably stabilizes the shock oscillations. For EF Eri, the mass of the white dwarf based on hard X-ray observations is greater than 0.6 solar mass.

Physical Parameters of Components in Close Binary Systems. V

NASA Astrophysics Data System (ADS)

Zola, S.; Kreiner, J. M.; Zakrzewski, B.; Kjurkchieva, D. P.; Marchev, D. V.; Baran, A.; Rucinski, S. M.; Ogloza, W.; Siwak, M.; Koziel, D.; Drozdz, M.; Pokrzywka, B.

2005-12-01

The paper presents combined spectroscopic and photometric orbital solutions for ten close binary systems: CN And, V776 Cas, FU Dra, UV Lyn, BB Peg, V592 Per, OU Ser, EQ Tau, HN UMa and HT Vir. The photometric data consist of new multicolor light curves, while the spectroscopy has been recently obtained within the radial velocity program at the David Dunlap Observatory (DDO). Absolute parameters of the components for these binary systems are derived. Our results confirm that CN And is not a contact system. Its configuration is semi-detached with the secondary component filling its Roche lobe. The configuration of nine other systems is contact. Three systems (V776 Cas, V592 Per and OU Ser) have high (44-77%) and six (FU Dra, UV Lyn, BB Peg, EQ Tau, HN UMa and HT Vir) low or intermediate (8-32%) fill-out factors. The absolute physical parameters are derived.

BVR{sub c}I{sub c} observations and analyses on V2421 Cygni, a precontact W UMa binary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samec, R. G.; Shebs, Travis S.; Faulkner, D. R.

2014-01-01

We present the first precision BVRI light curves, synthetic light curve solutions, and a period study for the high amplitude solar type binary, V2421 Cygni. The light curves have the appearance of an Algol (EA) type; however, it is made up of dwarf solar type components in a detached mode with a period of only 0.6331 days with an amplitude of about a full magnitude, i.e., it is a precontact W UMa binary. Flare-like disruptions occur in the light curves following the primary and secondary eclipses possibly due to the line-of-sight track of a gas stream. An associated stream spotmore » and splash spot cause bright equatorial spots on the stellar surface of the primary star. The more massive star is the gainer, making this system a classic, albeit dwarf, Algol.« less

Variability in the Milky Way: Contact Binaries as Diagnostic Tools

NASA Astrophysics Data System (ADS)

de Grijs, R.; Chen, X.; Deng, L.

2017-07-01

We used the 50 cm Binocular Network (50BiN) telescope at Delingha Station (Qinghai Province) of Purple Mountain Observatory (Chinese Academy of Sciences) to obtain simultaneous V- and R-band observations of the old open cluster NGC 188. Our aim was a search for populations of variable stars. We derived light-curve solutions for six W Ursae Majoris (W UMa) eclipsing-binary systems and estimated their orbital parameters. The resulting distance to the W UMas is independent of the physical characteristics of the host cluster. We next determined the current best period-luminosity relations for contact binaries (CBs; scatter σ<0.10 mag). We conclude that CBs can be used as distance tracers with better than 5% uncertainty. We apply our new relations to the 102 CBs in the Large Magellanic Cloud, which yields a distance modulus of (m-M)V,0=18.41±0.20 mag.

Recent developments on SU UMa stars - theory vs. observation

NASA Astrophysics Data System (ADS)

Cannizzo, John K.

2015-01-01

Kepler light curves of short period dwarf novae have resparked interest in the nature of superoutbursts and led to the question: Is the thermal-tidal instability needed, or can the plain vanilla version of the accretion disk limit cycle do the job all by itself? A detailed time-resolved study of an eclipsing SU UMa system during superoutburst onset should settle the question - if there is a dramatic contraction of the disk at superoutburst onset, Osaki's thermal-tidal model would be preferred; if not, the plain disk instability model would be sufficient. I will present recent results that support the contention by Osaki & Kato that the time varying negative superhump frequencies can be taken as a surrogate for the outer disk radius variations. Finally, it may be necessaryto look beyond the short period dwarf novae to gain perspective on the nature of embedded precursors in long outbursts.

Absolute and geometric parameters of contact binary BO Arietis

NASA Astrophysics Data System (ADS)

Gürol, B.; Gürsoytrak, S. H.; Bradstreet, D. H.

2015-08-01

We present the results of our investigation on the geometrical and physical parameters of the W UMa type binary system BO Ari from analyzed CCD (BVRI) light curves and radial velocity data. The photometric data were obtained in 2009 and 2010 at Ankara University Observatory (AUO) and the spectroscopic observations were made in 2007 and 2010 at TUBITAK National Observatory (TUG). These light and radial velocity observations were analyzed simultaneously by using the Wilson-Devinney (2013 revision) code to obtain absolute and geometrical parameters. The system was determined to be an A-type W UMa system. Combining our photometric solution with the spectroscopic data we derived masses and radii of the eclipsing system to be M1 = 0.995M⊙,M2 = 0.189M⊙,R1 = 1.090R⊙ and R2 = 0.515R⊙ . Finally, we discuss the evolutionary status of the system.

Absolute and geometric parameters of contact binary V1918 Cyg

NASA Astrophysics Data System (ADS)

Gürol, B.

2016-08-01

We present the results of our investigation on the geometrical and physical parameters of the W UMa type binary system V1918 Cyg from analyzed CCD (BVR) light curves and radial velocity data. We used the photometric data published by Yang et al. (2013) and spectroscopic data obtained in 2012 at TUBITAK National Observatory (TUG). The light and radial velocity observations were analyzed simultaneously by using the Wilson-Devinney (2015 revision) code to obtain absolute and geometrical parameters of the system. It is confirmed that the system is an A-type W UMa as indicated by Yang et al. (2013). Combining our spectroscopic data with the photometric solution we derived masses and radii of the eclipsing system as M1 = 1.302M⊙ , M2 = 0.362M⊙ , R1 = 1.362R⊙ and R2 = 0.762R⊙ . Finally, we discuss the evolutionary status of the system.

Multimodal Interfaces: Literature Review of Ecological Interface Design, Multimodal Perception and Attention, and Intelligent Adaptive Multimodal Interfaces

DTIC Science & Technology

2010-05-01

Multimodal Interfaces Literature Review of Ecological Interface Design , Multimodal Perception and Attention, and Intelligent... Design , Multimodal Perception and Attention, and Intelligent Adaptive Multimodal Interfaces Wayne Giang, Sathya Santhakumaran, Ehsan Masnavi, Doug...Advanced Interface Design Laboratory, E2-1303N 200 University Avenue West Waterloo, Ontario Canada N2L 3G1 Contract Project Manager: Dr. Catherine

Discrete structural features among interface residue-level classes.

PubMed

Sowmya, Gopichandran; Ranganathan, Shoba

2015-01-01

Protein-protein interaction (PPI) is essential for molecular functions in biological cells. Investigation on protein interfaces of known complexes is an important step towards deciphering the driving forces of PPIs. Each PPI complex is specific, sensitive and selective to binding. Therefore, we have estimated the relative difference in percentage of polar residues between surface and the interface for each complex in a non-redundant heterodimer dataset of 278 complexes to understand the predominant forces driving binding. Our analysis showed ~60% of protein complexes with surface polarity greater than interface polarity (designated as class A). However, a considerable number of complexes (~40%) have interface polarity greater than surface polarity, (designated as class B), with a significantly different p-value of 1.66E-45 from class A. Comprehensive analyses of protein complexes show that interface features such as interface area, interface polarity abundance, solvation free energy gain upon interface formation, binding energy and the percentage of interface charged residue abundance distinguish among class A and class B complexes, while electrostatic visualization maps also help differentiate interface classes among complexes. Class A complexes are classical with abundant non-polar interactions at the interface; however class B complexes have abundant polar interactions at the interface, similar to protein surface characteristics. Five physicochemical interface features analyzed from the protein heterodimer dataset are discriminatory among the interface residue-level classes. These novel observations find application in developing residue-level models for protein-protein binding prediction, protein-protein docking studies and interface inhibitor design as drugs.

Discrete structural features among interface residue-level classes

PubMed Central

2015-01-01

Background Protein-protein interaction (PPI) is essential for molecular functions in biological cells. Investigation on protein interfaces of known complexes is an important step towards deciphering the driving forces of PPIs. Each PPI complex is specific, sensitive and selective to binding. Therefore, we have estimated the relative difference in percentage of polar residues between surface and the interface for each complex in a non-redundant heterodimer dataset of 278 complexes to understand the predominant forces driving binding. Results Our analysis showed ~60% of protein complexes with surface polarity greater than interface polarity (designated as class A). However, a considerable number of complexes (~40%) have interface polarity greater than surface polarity, (designated as class B), with a significantly different p-value of 1.66E-45 from class A. Comprehensive analyses of protein complexes show that interface features such as interface area, interface polarity abundance, solvation free energy gain upon interface formation, binding energy and the percentage of interface charged residue abundance distinguish among class A and class B complexes, while electrostatic visualization maps also help differentiate interface classes among complexes. Conclusions Class A complexes are classical with abundant non-polar interactions at the interface; however class B complexes have abundant polar interactions at the interface, similar to protein surface characteristics. Five physicochemical interface features analyzed from the protein heterodimer dataset are discriminatory among the interface residue-level classes. These novel observations find application in developing residue-level models for protein-protein binding prediction, protein-protein docking studies and interface inhibitor design as drugs. PMID:26679043

A database for TMT interface control documents

NASA Astrophysics Data System (ADS)

Gillies, Kim; Roberts, Scott; Brighton, Allan; Rogers, John

2016-08-01

The TMT Software System consists of software components that interact with one another through a software infrastructure called TMT Common Software (CSW). CSW consists of software services and library code that is used by developers to create the subsystems and components that participate in the software system. CSW also defines the types of components that can be constructed and their roles. The use of common component types and shared middleware services allows standardized software interfaces for the components. A software system called the TMT Interface Database System was constructed to support the documentation of the interfaces for components based on CSW. The programmer describes a subsystem and each of its components using JSON-style text files. A command interface file describes each command a component can receive and any commands a component sends. The event interface files describe status, alarms, and events a component publishes and status and events subscribed to by a component. A web application was created to provide a user interface for the required features. Files are ingested into the software system's database. The user interface allows browsing subsystem interfaces, publishing versions of subsystem interfaces, and constructing and publishing interface control documents that consist of the intersection of two subsystem interfaces. All published subsystem interfaces and interface control documents are versioned for configuration control and follow the standard TMT change control processes. Subsystem interfaces and interface control documents can be visualized in the browser or exported as PDF files.

MIB Galerkin method for elliptic interface problems.

PubMed

Xia, Kelin; Zhan, Meng; Wei, Guo-Wei

2014-12-15

Material interfaces are omnipresent in the real-world structures and devices. Mathematical modeling of material interfaces often leads to elliptic partial differential equations (PDEs) with discontinuous coefficients and singular sources, which are commonly called elliptic interface problems. The development of high-order numerical schemes for elliptic interface problems has become a well defined field in applied and computational mathematics and attracted much attention in the past decades. Despite of significant advances, challenges remain in the construction of high-order schemes for nonsmooth interfaces, i.e., interfaces with geometric singularities, such as tips, cusps and sharp edges. The challenge of geometric singularities is amplified when they are associated with low solution regularities, e.g., tip-geometry effects in many fields. The present work introduces a matched interface and boundary (MIB) Galerkin method for solving two-dimensional (2D) elliptic PDEs with complex interfaces, geometric singularities and low solution regularities. The Cartesian grid based triangular elements are employed to avoid the time consuming mesh generation procedure. Consequently, the interface cuts through elements. To ensure the continuity of classic basis functions across the interface, two sets of overlapping elements, called MIB elements, are defined near the interface. As a result, differentiation can be computed near the interface as if there is no interface. Interpolation functions are constructed on MIB element spaces to smoothly extend function values across the interface. A set of lowest order interface jump conditions is enforced on the interface, which in turn, determines the interpolation functions. The performance of the proposed MIB Galerkin finite element method is validated by numerical experiments with a wide range of interface geometries, geometric singularities, low regularity solutions and grid resolutions. Extensive numerical studies confirm the designed second order convergence of the MIB Galerkin method in the L ∞ and L 2 errors. Some of the best results are obtained in the present work when the interface is C 1 or Lipschitz continuous and the solution is C 2 continuous.

Bromine monoxide emissions from Kilauea volcano - Hawai`i

NASA Astrophysics Data System (ADS)

Salerno, G. G.; Oppenheimer, C.; Tsanev, V. I.; Sutton, A. J.; Elias, T.

2009-12-01

Since the first detection of bromine monoxide (BrO) in volcanic plumes, there has been considerable interest in the atmospheric synthesis and impact of reactive halogens in volcanic plumes. We report here the first observations of BrO in the volcanic plume emitted from the summit of Kilauea volcano. We present data collected in 2007, 2008 and 2009 at Pu`u`O`o and Halema`uma`u crater by ground-based Differential Optical Absorption Spectroscopy (DOAS). In 2007, we did not detect any bromine compounds either from the summit or from the Pu`u`O`o plume. However, in 2008 and 2009, we found a good correlation between BrO and SO2 (SO2/BrO molar ratios of ~2000 and ~400) in the plume emitted by the new vent opened at Halema`uma`u crater in March 2008. We discuss the observed variations in BrO production and SO2/BrO ratios over time and contrasting the volcano summit and the east rift zone emissions (with respect to the two-stage degassing long recognized at Kilauea). Factors accounting for the variability include plume age and eruptive style. The presence of BrO in the plume from the new vent in Halema`uma`u crater might depend either on the high temperature from near-surface magma or vent geometry, combined with strong ultraviolet radiation promoting the ”bromine explosion”. Our BrO results significantly extend the global catalogue of volcanic reactive halogen degassing including, for the first time, data representing a hot-spot setting.

Curva de rotação óptica de ESO-LV 5100550

NASA Astrophysics Data System (ADS)

Carvalho, D. B.; Soares, D. S. L.

2003-08-01

ESO-LV 5100550 é o membro mais fraco do par de galáxias austral SBG 357 (Soares et al. 1995). É classificada no catálogo RC3 como uma espiral ordinária de tipo inicial (early-type); porém, uma análise morfológica sugere que ela tenha uma grande barra. O objetivo do estudo é determinar sua cinemática de tal modo que possamos inferir mais a respeito de sua dinâmica, provavelmente perturbada, já que se espera que esteja sob forte influência da companheira ESO-LV 5100560. Apresentarei resultados parciais determinados a partir de espectros obtidos com o instrumento Double Spectrograph montado no telescópio Hale do Monte Palomar, EUA. As observações foram realizadas por D.S.L. Soares, P.M.V. Veiga e T.E. Nordgren, em 1998. Foram tomados espectros de fenda longa posicionada sobre a linha dos nodos do disco e ao longo da suposta barra. Os dados foram reduzidos com uso do pacote IRAF. Obtivemos o perfil de velocidades radiais na linha de visada ao longo das fendas e calculamos o desvio para o vermelho cosmológico do sistema, com base no espectro central. Determinamos as curvas de rotação deprojetadas, com base em cálculos para os valores teóricos esperados das componentes de velocidades puramente circulares em um disco inclinado. A inclinação do disco, dado fundamental nesta deprojeção, foi estimada através da média das elipticidades das isofotas mais externas.

Determinação da composição química em nebulosas planetárias na direção do anticentro galáctico

NASA Astrophysics Data System (ADS)

Costa, R. D. D.; Uchida, M. M. M.; Maciel, W. J.

2003-08-01

Existe um gradiente radial de abundâncias no disco galáctico, cujo comportamento é razoavelmente bem conhecido para distâncias galactocêntricas entre 3 e 10 kpc. Foi obtido a partir de resultados derivados de nebulosas planetárias, regiões HII e estrelas, como as estrelas quentes de tipo O, B e aglomerados abertos. Com o objetivo de investigar o comportamento deste gradiente radial na região externa do disco, conhecida como anticentro galáctico, reportamos aqui os resultados finais da análise de uma amostra de nebulosas planetárias na direção do anticentro, observadas no LNA e no ESO entre 1995 e 2000. O uso de nebulosas planetárias permite o cálculo das abundâncias de elementos traçadores da evolução química do disco como oxigênio, argônio e neônio com o uso de técnicas de espectroscopia nebular. Os resultados indicam uma distribuição de abundâncias distinta daquela encontrada na vizinhança solar, mostrando que o gradiente radial diminui sensivelmente para distâncias galactocêntricas maiores que 10 kpc. Este resultado está de acordo com os mais recentes modelos de evolução química do disco, que prevêem uma diminuição ou mesmo um desaparecimento do gradiente radial no bordo externo do disco galáctico. (FAPESP/CNPq)

EUVE and IR observations of the Polars HU Aqr and AR UMa

NASA Astrophysics Data System (ADS)

Howell, S.; Ciardi, D.

1999-12-01

Simultaneous EUVE and ground-based near-infrared J and K observations of the magnetic CV HU Aqr were performed. The observations occurred during a super-high state never before observed in HU Aqr. The average EUVE count-rate was 30-60 times higher than had been measured previously, allowing us to present the first ever EUV spectra of HU Aqr. The near-infrared observations show a corresponding flux increase of 2-3 times over previous J and K observations. However, the near-infrared eclipse minimum during this super-high state are the same as seen in previous observations, indicating that the eclipse in the near-infrared is total. We present a detailed comparison of the EUV and near-infrared emission of HU Aqr as a function of orbital phase and discuss the geometry and physical properties of the high energy and infrared emitting regions. AR UMa is the brightest EUV source yet observed with the EUVE satellite and is also the polar with the largest magnetic field, 250 MG. EUVE observations of the polar AR UMa have allowed, for the first time, EUV time-resolved spectral analysis and radial velocity measurements. We present EUV phase-resolved photometry and spectroscopy and show that the He 304 emission line is not produced on the heated face of the secondary star, but emanates from the inner illuminated regions of the coupling region and accretion stream. We comment on the overall structure of the accretion geometry as well. The authors acknowledge partial support of the research by NASA cooperative agreement NCC5-138 via an EUVE guest Observer mini-grant.

Instrument interface description for NOAA 2000 instruments with European morning spacecraft and/or NOAA-OPQ spacecraft

NASA Technical Reports Server (NTRS)

1993-01-01

The purpose is to describe at a high level the common interface provisions and constraints placed on the NOAA-2000 instruments and the interfacing spacecraft elements in the following areas: electrical interface, mechanical interface, thermal interface, magnetic interface, electromagnetic compatibility, structural/mechanical environmental interface, contamination control, and the ionizing radiation environment. The requirements reflect the fact that these instruments must be compatible with a number of different polar orbiting satellite vehicles including the NOAA-OPQ satellites and the EUMETSAT METOP satellites.

International interface design for Space Station Freedom - Challenges and solutions

NASA Technical Reports Server (NTRS)

Mayo, Richard E.; Bolton, Gordon R.; Laurini, Daniele

1988-01-01

The definition of interfaces for the International Space Station is discussed, with a focus on negotiations between NASA and ESA. The program organization and division of responsibilities for the Space Station are outlined; the basic features of physical and functional interfaces are described; and particular attention is given to the interface management and documentation procedures, architectural control elements, interface implementation and verification, and examples of Columbus interface solutions (including mechanical, ECLSS, thermal-control, electrical, data-management, standardized user, and software interfaces). Diagrams, drawings, graphs, and tables listing interface types are provided.

Structural modifications due to interface chemistry at metal-nitride interfaces

DOE PAGES

Yadav, S. K.; Shao, S.; Wang, J.; ...

2015-11-27

Based on accurate first principles density functional theory (DFT) calculations, an unusual phenomenon of interfacial structural modifications, due to the interface chemistry influence is identified at two metal-nitride interfaces with strong metal-nitrogen affinity, Al/TiN {111} and Al/VN {111} interfaces. It is shown that at such interfaces, a faulted stacking structure is energetically preferred on the Al side of the interface. And both intrinsic and extrinsic stacking fault energies in the vicinity Al layers are negligibly small. However, such phenomenon does not occur in Pt/TiN and Pt/VN interfaces because of the weak Pt-N affinity. As a result, corresponding to structural energiesmore » of metal-nitride interfaces, the linear elasticity analysis predicts characteristics of interfacial misfit dislocations at metal-nitride interfaces.« less

Structural modifications due to interface chemistry at metal-nitride interfaces

PubMed Central

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

2015-01-01

Based on accurate first principles density functional theory (DFT) calculations, an unusual phenomenon of interfacial structural modifications, due to the interface chemistry influence is identified at two metal-nitride interfaces with strong metal-nitrogen affinity, Al/TiN {111} and Al/VN {111} interfaces. It is shown that at such interfaces, a faulted stacking structure is energetically preferred on the Al side of the interface. And both intrinsic and extrinsic stacking fault energies in the vicinity Al layers are negligibly small. However, such phenomenon does not occur in Pt/TiN and Pt/VN interfaces because of the weak Pt-N affinity. Corresponding to structural energies of metal-nitride interfaces, the linear elasticity analysis predicts characteristics of interfacial misfit dislocations at metal-nitride interfaces. PMID:26611639

Training Manual for Elements of Interface Definition and Control

NASA Technical Reports Server (NTRS)

Lalli, Vincent R. (Editor); Kastner, Robert E. (Editor); Hartt, Henry N. (Editor)

1997-01-01

The primary thrust of this manual is to ensure that the format and information needed to control interfaces between equipment are clear and understandable. The emphasis is on controlling the engineering design of the interface and not on the functional performance requirements of the system or the internal workings of the interfacing equipment. Interface control should take place, with rare exception, at the interfacing elements and no further. There are two essential sections of the manual. Chapter 2, Principles of Interface Control, discusses how interfaces are defined. It describes different types of interfaces to be considered and recommends a format for the documentation necessary for adequate interface control. Chapter 3, The Process: Through the Design Phases, provides tailored guidance for interface definition and control. This manual can be used to improve planned or existing interface control processes during system design and development. It can also be used to refresh and update the corporate knowledge base. The information presented herein will reduce the amount of paper and data required in interface definition and control processes by as much as 50 percent and will shorten the time required to prepare an interface control document. It also highlights the essential technical parameters that ensure that flight subsystems will indeed fit together and function as intended after assembly and checkout.

Properties of interfaces and transport across them.

PubMed

Cabezas, H

2000-01-01

Much of the biological activity in cell cytoplasm occurs in compartments some of which may be formed, as suggested in this book, by phase separation, and many of the functions of such compartments depend on the transport or exchange of molecules across interfaces. Thus a fundamentally based discussion of the properties of phases, interfaces, and diffusive transport across interfaces has been given to further elucidate these phenomena. An operational criterion for the width of interfaces is given in terms of molecular and physical arguments, and the properties of molecules inside phases and interfaces are discussed in terms of molecular arguments. In general, the properties of the interface become important when the molecules diffusing across are smaller than the width of the interface. Equilibrium partitioning, Donnan phenomena, and electrochemical potentials at interfaces are also discussed in detail. The mathematical expressions for modeling transport across interfaces are discussed in detail. These describe a practical and detailed model for transport across interfaces. For molecules smaller than the width of the interface, this includes a detailed model for diffusion inside the interface. Last, the question of the time scale for phase formation and equilibration in biological systems is discussed.

AW UMa observed with MOST satellite

NASA Astrophysics Data System (ADS)

Rucinski, S. M.; Matthews, J. M.; Cameron, C.; Guenther, D. B.; Kuschnig, R.; Moffat, A. F. J.; Rowe, J. F.; Sasselov, D.; Weiss, W. W.

2013-11-01

MOST observations were obtained to search for photometric non-radial oscillations; none was detected with an upper limit of 0.0001 in relative amplitude. A single, precise moment of the primary eclipse confirms the progressive shortening of the orbital period.

Molecular architecture of protein-RNA recognition sites.

PubMed

Barik, Amita; C, Nithin; Pilla, Smita P; Bahadur, Ranjit Prasad

2015-01-01

The molecular architecture of protein-RNA interfaces are analyzed using a non-redundant dataset of 152 protein-RNA complexes. We find that an average protein-RNA interface is smaller than an average protein-DNA interface but larger than an average protein-protein interface. Among the different classes of protein-RNA complexes, interfaces with tRNA are the largest, while the interfaces with the single-stranded RNA are the smallest. Significantly, RNA contributes more to the interface area than its partner protein. Moreover, unlike protein-protein interfaces where the side chain contributes less to the interface area compared to the main chain, the main chain and side chain contributions flipped in protein-RNA interfaces. We find that the protein surface in contact with the RNA in protein-RNA complexes is better packed than that in contact with the DNA in protein-DNA complexes, but loosely packed than that in contact with the protein in protein-protein complexes. Shape complementarity and electrostatic potential are the two major factors that determine the specificity of the protein-RNA interaction. We find that the H-bond density at the protein-RNA interfaces is similar with that of protein-DNA interfaces but higher than the protein-protein interfaces. Unlike protein-DNA interfaces where the deoxyribose has little role in intermolecular H-bonds, due to the presence of an oxygen atom at the 2' position, the ribose in RNA plays significant role in protein-RNA H-bonds. We find that besides H-bonds, salt bridges and stacking interactions also play significant role in stabilizing protein-nucleic acids interfaces; however, their contribution at the protein-protein interfaces is insignificant.

Autoimmune hepatitis in children: progression of 20 cases in northern Mexico.

PubMed

Nares-Cisneros, J; Jaramillo-Rodríguez, Y

2014-01-01

Autoimmune hepatitis (AIH) is a chronic inflammatory disease of the liver with nonspecific clinical manifestations that causes greater liver damage in children than in adults. To analyze the clinical progression, biochemical profiles, histopathologic changes, and treatment response in 20 children with AIH. A retrospective study was carried out on the variables associated with clinical progression, diagnosis, and treatment response in children seen at the the Unidad Médica de Alta Especialidad (UMAE) No. 71 IMSS in Torreón, Coahuila, Mexico, from 1992 to 2012. Twenty patients were analyzed, 75% with type 1 AIH (AIH-1) and 25% with type 2 AIH (AIH-2). Girls predominated with a 3:1 ratio of girls to boys. The mean age was 10.07 ± 6.53 years for the AIH-1 cases and 6.75 ± 3.77 years for the AIH-2 cases. There was an association with immunologic diseases in 40% of the patients. The patients in the AIH-2 group had greater biochemical profile alterations and IgA deficiency. Anti-nuclear antibody and anti-smooth muscle antibody were positive in 100% of the patients with AIH-1, and anti-liver kidney microsomal type 1 antibody was positive in 100% of the AIH-2 patients. Liver biopsy revealed interface hepatitis in both groups. The AIH-2 group responded more quickly to treatment, but had a higher recurrence rate. Autoimmune hepatitis in the pediatric patient should be suspected in order to make an early diagnosis and thereby establish opportune treatment. Determining the type of AIH is necessary for making adequate diagnosis and for achieving a better outcome in relation to recurrence and complication rates. Copyright © 2014 Asociación Mexicana de Gastroenterología. Published by Masson Doyma México S.A. All rights reserved.

Interface bonding of SA508-3 steel under deformation and high temperature diffusion

NASA Astrophysics Data System (ADS)

Xu, Bin; Shao, Chunjuan; Sun, Mingyue

2018-05-01

There are mainly two parameters affecting high temperature interface bonding: deformation and diffusion. To study these two parameters, interface bonding of SA508-3 bainitic steel at 1100°C are simulated by gleeble3500 thermal simulator. The results show that interface of SA508-3 steel can be bonded under deformation and high temperature. For a specimen pressed at 1100°C without further high temperature diffusion, a reduction ratio of 30% can make the interface begun to bond, but the interface is still part of the grain boundary and small grains exist near the interface. When reduction ratio reaches 50%, the interface can be completely bonded and the microstructure near the interface is the same as that of the base material. When deformation is small, long time diffusion can also help the interface bonding. The results show that when the diffusion time is long enough, the interface under small deformation can also be bonded. For a specimen holding for 24h at 1100°C, only 13% reduction ratio is enough for interface bonding.

Multiple network interface core apparatus and method

DOEpatents

Underwood, Keith D [Albuquerque, NM; Hemmert, Karl Scott [Albuquerque, NM

2011-04-26

A network interface controller and network interface control method comprising providing a single integrated circuit as a network interface controller and employing a plurality of network interface cores on the single integrated circuit.

Thermal transport across metal silicide-silicon interfaces: An experimental comparison between epitaxial and nonepitaxial interfaces

NASA Astrophysics Data System (ADS)

Ye, Ning; Feser, Joseph P.; Sadasivam, Sridhar; Fisher, Timothy S.; Wang, Tianshi; Ni, Chaoying; Janotti, Anderson

2017-02-01

Silicides are used extensively in nano- and microdevices due to their low electrical resistivity, low contact resistance to silicon, and their process compatibility. In this work, the thermal interface conductance of TiSi2, CoSi2, NiSi, and PtSi are studied using time-domain thermoreflectance. Exploiting the fact that most silicides formed on Si(111) substrates grow epitaxially, while most silicides on Si(100) do not, we study the effect of epitaxy, and show that for a wide variety of interfaces there is no dependence of interface conductance on the detailed structure of the interface. In particular, there is no difference in the thermal interface conductance between epitaxial and nonepitaxial silicide/silicon interfaces, nor between epitaxial interfaces with different interface orientations. While these silicide-based interfaces yield the highest reported interface conductances of any known interface with silicon, none of the interfaces studied are found to operate close to the phonon radiation limit, indicating that phonon transmission coefficients are nonunity in all cases and yet remain insensitive to interfacial structure. In the case of CoSi2, a comparison is made with detailed computational models using (1) full-dispersion diffuse mismatch modeling (DMM) including the effect of near-interfacial strain, and (2) an atomistic Green' function (AGF) approach that integrates near-interface changes in the interatomic force constants obtained through density functional perturbation theory. Above 100 K, the AGF approach significantly underpredicts interface conductance suggesting that energy transport does not occur purely by coherent transmission of phonons, even for epitaxial interfaces. The full-dispersion DMM closely predicts the experimentally observed interface conductances for CoSi2, NiSi, and TiSi2 interfaces, while it remains an open question whether inelastic scattering, cross-interfacial electron-phonon coupling, or other mechanisms could also account for the high-temperature behavior. The effect of degenerate semiconductor dopant concentration on metal-semiconductor thermal interface conductance was also investigated with the result that we have found no dependencies of the thermal interface conductances up to (n or p type) ≈1 ×1019 cm-3, indicating that there is no significant direct electronic transport and no transport effects that depend on long-range metal-semiconductor band alignment.

Adhesion of voids to bimetal interfaces with non-uniform energies

DOE PAGES

Zheng, Shijian; Shao, Shuai; Zhang, Jian; ...

2015-10-21

Interface engineering has become an important strategy for designing radiation-resistant materials. Critical to its success is fundamental understanding of the interactions between interfaces and radiation-induced defects, such as voids. Using transmission electron microscopy, here we report an interesting phenomenon in their interaction, wherein voids adhere to only one side of the bimetal interfaces rather than overlapping them. We show that this asymmetrical void-interface interaction is a consequence of differing surface energies of the two metals and non-uniformity in their interface formation energy. Specifically, voids grow within the phase of lower surface energy and wet only the high-interface energy regions. Furthermore,more » because this outcome cannot be accounted for by wetting of interfaces with uniform internal energy, our report provides experimental evidence that bimetal interfaces contain non-uniform internal energy distributions. Ultimately, this work also indicates that to design irradiation-resistant materials, we can avoid void-interface overlap via tuning the configurations of interfaces.« less

An adaptive simplex cut-cell method for high-order discontinuous Galerkin discretizations of elliptic interface problems and conjugate heat transfer problems

NASA Astrophysics Data System (ADS)

Sun, Huafei; Darmofal, David L.

2014-12-01

In this paper we propose a new high-order solution framework for interface problems on non-interface-conforming meshes. The framework consists of a discontinuous Galerkin (DG) discretization, a simplex cut-cell technique, and an output-based adaptive scheme. We first present a DG discretization with a dual-consistent output evaluation for elliptic interface problems on interface-conforming meshes, and then extend the method to handle multi-physics interface problems, in particular conjugate heat transfer (CHT) problems. The method is then applied to non-interface-conforming meshes using a cut-cell technique, where the interface definition is completely separate from the mesh generation process. No assumption is made on the interface shape (other than Lipschitz continuity). We then equip our strategy with an output-based adaptive scheme for an accurate output prediction. Through numerical examples, we demonstrate high-order convergence for elliptic interface problems and CHT problems with both smooth and non-smooth interface shapes.

Atomistic modeling of Mg/Nb interfaces: shear strength and interaction with lattice glide dislocations

DOE PAGES

Yadav, Satyesh Kumar; Shao, S.; Chen, Youxing; ...

2017-10-17

Here, using a newly developed embedded-atom-method potential for Mg–Nb, the semi-coherent Mg/Nb interface with the Kurdjumov–Sachs orientation relationship is studied. Atomistic simulations have been carried out to understand the shear strength of the interface, as well as the interaction between lattice glide dislocations and the interface. The interface shear mechanisms are dependent on the shear loading directions, through either interface sliding between Mg and Nb atomic layers or nucleation and gliding of Shockley partial dislocations in between the first two atomic planes in Mg at the interface. The shear strength for the Mg/Nb interface is found to be generally high,more » in the range of 0.9–1.3 GPa depending on the shear direction. As a consequence, the extents of dislocation core spread into the interface are considerably small, especially when compared to the case of other “weak” interfaces such as the Cu/Nb interface.« less

Variational Implicit Solvation with Solute Molecular Mechanics: From Diffuse-Interface to Sharp-Interface Models.

PubMed

Li, Bo; Zhao, Yanxiang

2013-01-01

Central in a variational implicit-solvent description of biomolecular solvation is an effective free-energy functional of the solute atomic positions and the solute-solvent interface (i.e., the dielectric boundary). The free-energy functional couples together the solute molecular mechanical interaction energy, the solute-solvent interfacial energy, the solute-solvent van der Waals interaction energy, and the electrostatic energy. In recent years, the sharp-interface version of the variational implicit-solvent model has been developed and used for numerical computations of molecular solvation. In this work, we propose a diffuse-interface version of the variational implicit-solvent model with solute molecular mechanics. We also analyze both the sharp-interface and diffuse-interface models. We prove the existence of free-energy minimizers and obtain their bounds. We also prove the convergence of the diffuse-interface model to the sharp-interface model in the sense of Γ-convergence. We further discuss properties of sharp-interface free-energy minimizers, the boundary conditions and the coupling of the Poisson-Boltzmann equation in the diffuse-interface model, and the convergence of forces from diffuse-interface to sharp-interface descriptions. Our analysis relies on the previous works on the problem of minimizing surface areas and on our observations on the coupling between solute molecular mechanical interactions with the continuum solvent. Our studies justify rigorously the self consistency of the proposed diffuse-interface variational models of implicit solvation.

Ion-Specific Induced Fluctuations and Free Energetics of Aqueous Protein Hydrophobic Interfaces: Toward Connecting to Specific-Ion Behaviors at Aqueous Liquid–Vapor Interfaces

PubMed Central

2015-01-01

We explore anion-induced interface fluctuations near protein–water interfaces using coarse-grained representations of interfaces as proposed by Willard and Chandler (J. Phys. Chem. B2010, 114, 1954−195820055377). We use umbrella sampling molecular dynamics to compute potentials of mean force along a reaction coordinate bridging the state where the anion is fully solvated and one where it is biased via harmonic restraints to remain at the protein–water interface. Specifically, we focus on fluctuations of an interface between water and a hydrophobic region of hydrophobin-II (HFBII), a 71 amino acid residue protein expressed by filamentous fungi and known for its ability to form hydrophobically mediated self-assemblies at interfaces such as a water/air interface. We consider the anions chloride and iodide that have been shown previously by simulations as displaying specific-ion behaviors at aqueous liquid–vapor interfaces. We find that as in the case of a pure liquid–vapor interface, at the hydrophobic protein–water interface, the larger, less charge-dense iodide anion displays a marginal interfacial stability compared with that of the smaller, more charge-dense chloride anion. Furthermore, consistent with the results at aqueous liquid–vapor interfaces, we find that iodide induces larger fluctuations of the protein–water interface than chloride. PMID:24701961

National Airspace System interface management plan

DOT National Transportation Integrated Search

1986-01-01

This document is intended to implement Interface Management for interfacing subsystems of the National Airspace System (NAS) and for external NAS interfaces by establishing a process which assures that: Interface requirements are agreed to by interfa...

System and methods for reducing harmonic distortion in electrical converters

DOEpatents

Kajouke, Lateef A; Perisic, Milun; Ransom, Ray M

2013-12-03

Systems and methods are provided for delivering energy using an energy conversion module. An exemplary method for delivering energy from an input interface to an output interface using an energy converison module coupled between the input interface and the output interface comprises the steps of determining an input voltage reference for the input interface based on a desired output voltage and a measured voltage and the output interface, determining a duty cycle control value based on a ratio of the input voltage reference and the measured voltage, operating one or more switching elements of the energy conversion module to deliver energy from the input interface to the output interface to the output interface with a duty cycle influenced by the dute cycle control value.

Interface wave propagation and edge conversion at a low stiffness interphase layer between two solids: A numerical study.

PubMed

Cho, Hideo; Rokhlin, Stanislav I

2015-09-01

The Rayleigh-to-interface wave conversion and the propagation of the resulting symmetric and antisymmetric modes on a bonded interface between solids is analyzed by the two dimensional finite difference time domain method. The propagated patterns were visualized to improve understanding of the phenomena. It is found that the partition of the energy of the interface waves above and below the interface changes repeatedly with propagation distance due to interference between the two modes which have slightly different phase velocities. The destructive interference of those two modes results in dips in the amplitude spectrum of the interface waves, which shift in frequency with propagation distance. The Rayleigh wave received that is created by the interface wave at the exit corner of the joint also shows interference dips in its spectrum. Those dips depend on the interface properties and can potentially be used for interface characterization. Conversion factors related to the interface wave at the upward and downward corners are determined and discussed. As a result, the total transition factor through the upward and downward corners for the interface wave was estimated as 0.37 and would be sufficiently large to probe the interface by coupling from the Rayleigh to the interface wave. Copyright © 2015 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yadav, Satyesh Kumar; Shao, S.; Chen, Youxing

Here, using a newly developed embedded-atom-method potential for Mg–Nb, the semi-coherent Mg/Nb interface with the Kurdjumov–Sachs orientation relationship is studied. Atomistic simulations have been carried out to understand the shear strength of the interface, as well as the interaction between lattice glide dislocations and the interface. The interface shear mechanisms are dependent on the shear loading directions, through either interface sliding between Mg and Nb atomic layers or nucleation and gliding of Shockley partial dislocations in between the first two atomic planes in Mg at the interface. The shear strength for the Mg/Nb interface is found to be generally high,more » in the range of 0.9–1.3 GPa depending on the shear direction. As a consequence, the extents of dislocation core spread into the interface are considerably small, especially when compared to the case of other “weak” interfaces such as the Cu/Nb interface.« less

Understanding the liquid-liquid (water-hexane) interface

NASA Astrophysics Data System (ADS)

Murad, Sohail; Puri, Ishwar K.

2017-10-01

Nonequilibrium molecular dynamics simulations are employed to investigate the interfacial thermal resistance of nanoscale hexane-water interfaces subject to an applied heat flux. Our studies show that these liquid-liquid interfaces exhibit behavior significantly dissimilar to that of solid-liquid and solid-vapor interfaces. Notably, the thermal resistance of a hexane-water interface is contingent on the interfacial temperature gradient alone with negligible dependence on the mean interfacial temperature, while the solid-liquid dependent strongly on the interfacial temperature. Application of a heat flux also increases the interface thickness significantly as compared to an equilibrium isothermal interface. Since liquid-liquid interfaces have been proposed for diverse applications, e.g., sensors for wastewater treatment and for extraction of toxic ions from water, they can be designed to be wider by applying a heat flux. This may allow the interface to be used for other applications not possible currently because of the very limited thickness of the interface in isothermal systems.

Design of efficient and simple interface testing equipment for opto-electric tracking system

NASA Astrophysics Data System (ADS)

Liu, Qiong; Deng, Chao; Tian, Jing; Mao, Yao

2016-10-01

Interface testing for opto-electric tracking system is one important work to assure system running performance, aiming to verify the design result of every electronic interface matching the communication protocols or not, by different levels. Opto-electric tracking system nowadays is more complicated, composed of many functional units. Usually, interface testing is executed between units manufactured completely, highly depending on unit design and manufacture progress as well as relative people. As a result, it always takes days or weeks, inefficiently. To solve the problem, this paper promotes an efficient and simple interface testing equipment for opto-electric tracking system, consisting of optional interface circuit card, processor and test program. The hardware cards provide matched hardware interface(s), easily offered from hardware engineer. Automatic code generation technique is imported, providing adaption to new communication protocols. Automatic acquiring items, automatic constructing code architecture and automatic encoding are used to form a new program quickly with adaption. After simple steps, a standard customized new interface testing equipment with matching test program and interface(s) is ready for a waiting-test system in minutes. The efficient and simple interface testing equipment for opto-electric tracking system has worked for many opto-electric tracking system to test entire or part interfaces, reducing test time from days to hours, greatly improving test efficiency, with high software quality and stability, without manual coding. Used as a common tool, the efficient and simple interface testing equipment for opto-electric tracking system promoted by this paper has changed traditional interface testing method and created much higher efficiency.

Characterization of Defects in Scaled Mis Dielectrics with Variable Frequency Charge Pumping

NASA Astrophysics Data System (ADS)

Paulsen, Ronald Eugene

1995-01-01

Historically, the interface trap has been extensively investigated to determine the effects on device performance. Recently, much attention has been paid to trapping in near-interface oxide traps. Performance of high precision analog circuitry is affected by charge trapping in near-interface oxide traps which produces hysteresis, charge redistribution errors, and dielectric relaxation effects. In addition, the performance of low power digital circuitry, with reduced noise margins, may be drastically affected by the threshold voltage shifts associated with charge trapping in near -interface oxide traps. Since near-interface oxide traps may substantially alter the performance of devices, complete characterization of these defects is necessary. In this dissertation a new characterization technique, variable frequency charge pumping, is introduced which allows charge trapped at the interface to be distinguished from the charge trapped within the oxide. The new experimental technique is an extension of the charge pumping technique to low frequencies such that tunneling may occur from interface traps to near-interface oxide traps. A generalized charge pumping model, based on Shockley-Read-Hall statistics and trap-to-trap tunneling theory, has been developed which allows a more complete characterization of near-interface oxide traps. A pair of coupled differential equations governing the rate of change of occupied interface and near-interface oxide traps have been developed. Due to the experimental conditions in the charge pumping technique the equations may be decoupled, leading to an equation governing the rate of change of occupied interface traps and an equation governing the rate of change of occcupied near-interface oxide traps. Solving the interface trap equation and applying non-steady state charge dynamics leads to an interface trap component of the charge pumping current. In addition, solution to the near-interface oxide trap equation leads to an additional oxide trap component to the charge pumping current. Numerical simulations have been performed to support the analytical development of the generalized charge pumping model. By varying the frequency of the applied charge pumping waveform and monitoring the charge recombined per cycle, the contributions from interface traps may be separated from the contributions of the near-interface oxide traps. The generalized charge pumping model allows characterization of the density and spatial distribution of near-interface oxide traps from this variable frequency charge pumping technique. Characterization of interface and near-interface oxide trap generation has been performed on devices exposed to ionizing radiation, hot electron injection, and high -field/Fowler-Nordheim stressing. Finally, using SONOS nonvolatile memory devices, a framework has been established for experimentally determining not only the spatial distribution of near-interface oxide traps, but also the energetic distribution. An experimental approach, based on tri-level charge pumping, is discussed which allows the energetic distribution of near-interface oxide traps to be determined.

Human/Computer Interfacing in Educational Environments.

ERIC Educational Resources Information Center

Sarti, Luigi

1992-01-01

This discussion of educational applications of user interfaces covers the benefits of adopting database techniques in organizing multimedia materials; the evolution of user interface technology, including teletype interfaces, analogic overlay graphics, window interfaces, and adaptive systems; application design problems, including the…

Interface Provides Standard-Bus Communication

NASA Technical Reports Server (NTRS)

Culliton, William G.

1995-01-01

Microprocessor-controlled interface (IEEE-488/LVABI) incorporates service-request and direct-memory-access features. Is circuit card enabling digital communication between system called "laser auto-covariance buffer interface" (LVABI) and compatible personal computer via general-purpose interface bus (GPIB) conforming to Institute for Electrical and Electronics Engineers (IEEE) Standard 488. Interface serves as second interface enabling first interface to exploit advantages of GPIB, via utility software written specifically for GPIB. Advantages include compatibility with multitasking and support of communication among multiple computers. Basic concept also applied in designing interfaces for circuits other than LVABI for unidirectional or bidirectional handling of parallel data up to 16 bits wide.

Project Interface Requirements Process Including Shuttle Lessons Learned

NASA Technical Reports Server (NTRS)

Bauch, Garland T.

2010-01-01

Most failures occur at interfaces between organizations and hardware. Processing interface requirements at the start of a project life cycle will reduce the likelihood of costly interface changes/failures later. This can be done by adding Interface Control Documents (ICDs) to the Project top level drawing tree, providing technical direction to the Projects for interface requirements, and by funding the interface requirements function directly from the Project Manager's office. The interface requirements function within the Project Systems Engineering and Integration (SE&I) Office would work in-line with the project element design engineers early in the life cycle to enhance communications and negotiate technical issues between the elements. This function would work as the technical arm of the Project Manager to help ensure that the Project cost, schedule, and risk objectives can be met during the Life Cycle. Some ICD Lessons Learned during the Space Shuttle Program (SSP) Life Cycle will include the use of hardware interface photos in the ICD, progressive life cycle design certification by analysis, test, & operations experience, assigning interface design engineers to Element Interface (EI) and Project technical panels, and linking interface design drawings with project build drawings

Charge interaction between particle-laden fluid interfaces.

PubMed

Xu, Hui; Kirkwood, John; Lask, Mauricio; Fuller, Gerald

2010-03-02

Experiments are described where two oil/water interfaces laden with charged particles move at close proximity relative to one another. The particles on one of the interfaces were observed to be attracted toward the point of closest approach, forming a denser particle monolayer, while the particles on the opposite interface were repelled away from this point, forming a particle depletion zone. Such particle attraction/repulsion was observed even if one of the interfaces was free of particles. This phenomenon can be explained by the electrostatic interaction between the two interfaces, which causes surface charges (charged particles and ions) to redistribute in order to satisfy surface electric equipotential at each interface. In a forced particle oscillation experiment, we demonstrated the control of charged particle positions on the interface by manipulating charge interaction between interfaces.

Compensation for electrical converter nonlinearities

DOEpatents

Perisic, Milun; Ransom, Ray M; Kajouke, Lateef A

2013-11-19

Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module between the input interface and the output interface, an inductive element between the input interface and the energy conversion module, and a control module. The control module determines a compensated duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface and operates the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value. The compensated duty cycle control value is influenced by the current through the inductive element and accounts for voltage across the switching elements of the energy conversion module.

The structural, electronic and optical properties of Au-ZnO interface structure from the first-principles calculation

NASA Astrophysics Data System (ADS)

Huo, Jin-Rong; Li, Lu; Cheng, Hai-Xia; Wang, Xiao-Xu; Zhang, Guo-Hua; Qian, Ping

2018-03-01

The interface structure, electronic and optical properties of Au-ZnO are studied using the first-principles calculation based on density functional theory (DFT). Given the interfacial distance, bonding configurations and terminated surface, we built the optimal interface structure and calculated the electronic and optical properties of the interface. The total density of states, partial electronic density of states, electric charge density and atomic populations (Mulliken) are also displayed. The results show that the electrons converge at O atoms at the interface, leading to a stronger binding of interfaces and thereby affecting the optical properties of interface structures. In addition, we present the binding energies of different interface structures. When the interface structure of Au-ZnO gets changed, furthermore, varying optical properties are exhibited.

Evaluation of Different Speech and Touch Interfaces to In-Vehicle Music Retrieval Systems

PubMed Central

Garay-Vega, L.; Pradhan, A. K.; Weinberg, G.; Schmidt-Nielsen, B.; Harsham, B.; Shen, Y.; Divekar, G.; Romoser, M.; Knodler, M.; Fisher, D. L.

2010-01-01

In-vehicle music retrieval systems are becoming more and more popular. Previous studies have shown that they pose a real hazard to drivers when the interface is a tactile one which requires multiple entries and a combination of manual control and visual feedback. Voice interfaces exist as an alternative. Such interfaces can require either multiple or single conversational turns. In this study, each of 17 participants between the ages of 18 and 30 years old was asked to use three different music-retrieval systems (one with a multiple entry touch interface, the iPod™, one with a multiple turn voice interface, interface B, and one with a single turn voice interface, interface C) while driving through a virtual world. Measures of secondary task performance, eye behavior, vehicle control, and workload were recorded. When compared with the touch interface, the voice interfaces reduced the total time drivers spent with their eyes off the forward roadway, especially in prolonged glances, as well as both the total number of glances away from the forward roadway and the perceived workload. Furthermore, when compared with driving without a secondary task, both voice interfaces did not significantly impact hazard anticipation, the frequency of long glances away from the forward roadway, or vehicle control. The multiple turn voice interface (B) significantly increased both the time it took drivers to complete the task and the workload. The implications for interface design and safety are discussed. PMID:20380920

Role of large-scale slip in mode II fracture of bimaterial interface produced by diffusion bonding

NASA Astrophysics Data System (ADS)

Fox, M. R.; Ghosh, A. K.

2001-08-01

Bimaterial interfaces present in diffusion-bonded (and in-situ) composites are often not flat interfaces. The unevenness of the interface can result not only from interface reaction products but also from long-range waviness associated with the surfaces of the component phases bonded together. Experimental studies aimed at determining interface mechanical properties generally ignore the departure in the local stress due to waviness and assume a theoretically flat interface. Furthermore, the commonly used testing methods involving superimposed tension often renders the interface so extremely brittle that if microplastic effects were present it becomes impossible to perceive them. This article examines the role of waviness of the interface and microplastic effects on crack initiation. To do this, a test was selected that provides significant stability against crack growth by superimposing compressive stresses. Mode II interface fracture was studied for NiAl/Mo model laminates using a recently developed asymmetrically loaded shear (ALS) interface shear test. The ALS test may be viewed as opposite of the laminate bend test. In the bend test, shear at the interface is created via tension on one surface of the bend, while in the ALS test, shear is created by compression on one side of the interface relative to the other. Normal to the interface, near the crack tip, an initially compressive state is replaced by slight tension due to Poisson’s expansion of the unbonded part of the compressed beam.

On the origin of the electrostatic potential difference at a liquid-vacuum interface.

PubMed

Harder, Edward; Roux, Benoît

2008-12-21

The microscopic origin of the interface potential calculated from computer simulations is elucidated by considering a simple model of molecules near an interface. The model posits that molecules are isotropically oriented and their charge density is Gaussian distributed. Molecules that have a charge density that is more negative toward their interior tend to give rise to a negative interface potential relative to the gaseous phase, while charge densities more positive toward their interior give rise to a positive interface potential. The interface potential for the model is compared to the interface potential computed from molecular dynamics simulations of the nonpolar vacuum-methane system and the polar vacuum-water interface system. The computed vacuum-methane interface potential from a molecular dynamics simulation (-220 mV) is captured with quantitative precision by the model. For the vacuum-water interface system, the model predicts a potential of -400 mV compared to -510 mV, calculated from a molecular dynamics simulation. The physical implications of this isotropic contribution to the interface potential is examined using the example of ion solvation in liquid methane.

Scale separation for multi-scale modeling of free-surface and two-phase flows with the conservative sharp interface method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, L.H., E-mail: Luhui.Han@tum.de; Hu, X.Y., E-mail: Xiangyu.Hu@tum.de; Adams, N.A., E-mail: Nikolaus.Adams@tum.de

In this paper we present a scale separation approach for multi-scale modeling of free-surface and two-phase flows with complex interface evolution. By performing a stimulus-response operation on the level-set function representing the interface, separation of resolvable and non-resolvable interface scales is achieved efficiently. Uniform positive and negative shifts of the level-set function are used to determine non-resolvable interface structures. Non-resolved interface structures are separated from the resolved ones and can be treated by a mixing model or a Lagrangian-particle model in order to preserve mass. Resolved interface structures are treated by the conservative sharp-interface model. Since the proposed scale separationmore » approach does not rely on topological information, unlike in previous work, it can be implemented in a straightforward fashion into a given level set based interface model. A number of two- and three-dimensional numerical tests demonstrate that the proposed method is able to cope with complex interface variations accurately and significantly increases robustness against underresolved interface structures.« less

Hydration of protein–RNA recognition sites

PubMed Central

Barik, Amita; Bahadur, Ranjit Prasad

2014-01-01

We investigate the role of water molecules in 89 protein–RNA complexes taken from the Protein Data Bank. Those with tRNA and single-stranded RNA are less hydrated than with duplex or ribosomal proteins. Protein–RNA interfaces are hydrated less than protein–DNA interfaces, but more than protein–protein interfaces. Majority of the waters at protein–RNA interfaces makes multiple H-bonds; however, a fraction do not make any. Those making H-bonds have preferences for the polar groups of RNA than its partner protein. The spatial distribution of waters makes interfaces with ribosomal proteins and single-stranded RNA relatively ‘dry’ than interfaces with tRNA and duplex RNA. In contrast to protein–DNA interfaces, mainly due to the presence of the 2′OH, the ribose in protein–RNA interfaces is hydrated more than the phosphate or the bases. The minor groove in protein–RNA interfaces is hydrated more than the major groove, while in protein–DNA interfaces it is reverse. The strands make the highest number of water-mediated H-bonds per unit interface area followed by the helices and the non-regular structures. The preserved waters at protein–RNA interfaces make higher number of H-bonds than the other waters. Preserved waters contribute toward the affinity in protein–RNA recognition and should be carefully treated while engineering protein–RNA interfaces. PMID:25114050

Nano- and microparticles at fluid and biological interfaces.

PubMed

Dasgupta, S; Auth, T; Gompper, G

2017-09-20

Systems with interfaces are abundant in both technological applications and biology. While a fluid interface separates two fluids, membranes separate the inside of vesicles from the outside, the interior of biological cells from the environment, and compartmentalize cells into organelles. The physical properties of interfaces are characterized by interface tension, those of membranes are characterized by bending and stretching elasticity. Amphiphilic molecules like surfactants that are added to a system with two immiscible fluids decrease the interface tension and induce a bending rigidity. Lipid bilayer membranes of vesicles can be stretched or compressed by osmotic pressure; in biological cells, also the presence of a cytoskeleton can induce membrane tension. If the thickness of the interface or the membrane is small compared with its lateral extension, both can be described using two-dimensional mathematical surfaces embedded in three-dimensional space. We review recent work on the interaction of particles with interfaces and membranes. This can be micrometer-sized particles at interfaces that stabilise emulsions or form colloidosomes, as well as typically nanometer-sized particles at membranes, such as viruses, parasites, and engineered drug delivery systems. In both cases, we first discuss the interaction of single particles with interfaces and membranes, e.g. particles in external fields, non-spherical particles, and particles at curved interfaces, followed by interface-mediated interaction between two particles, many-particle interactions, interface and membrane curvature-induced phenomena, and applications.

Circling motion and screen edges as an alternative input method for on-screen target manipulation.

PubMed

Ka, Hyun W; Simpson, Richard C

2017-04-01

To investigate a new alternative interaction method, called circling interface, for manipulating on-screen objects. To specify a target, the user makes a circling motion around the target. To specify a desired pointing command with the circling interface, each edge of the screen is used. The user selects a command before circling the target. To evaluate the circling interface, we conducted an experiment with 16 participants, comparing the performance on pointing tasks with different combinations of selection method (circling interface, physical mouse and dwelling interface) and input device (normal computer mouse, head pointer and joystick mouse emulator). A circling interface is compatible with many types of pointing devices, not requiring physical activation of mouse buttons, and is more efficient than dwell-clicking. Across all common pointing operations, the circling interface had a tendency to produce faster performance with a head-mounted mouse emulator than with a joystick mouse. The performance accuracy of the circling interface outperformed the dwelling interface. It was demonstrated that the circling interface has the potential as another alternative pointing method for selecting and manipulating objects in a graphical user interface. Implications for Rehabilitation A circling interface will improve clinical practice by providing an alternative pointing method that does not require physically activating mouse buttons and is more efficient than dwell-clicking. The Circling interface can also work with AAC devices.

Nano- and microparticles at fluid and biological interfaces

NASA Astrophysics Data System (ADS)

Dasgupta, S.; Auth, T.; Gompper, G.

2017-09-01

Systems with interfaces are abundant in both technological applications and biology. While a fluid interface separates two fluids, membranes separate the inside of vesicles from the outside, the interior of biological cells from the environment, and compartmentalize cells into organelles. The physical properties of interfaces are characterized by interface tension, those of membranes are characterized by bending and stretching elasticity. Amphiphilic molecules like surfactants that are added to a system with two immiscible fluids decrease the interface tension and induce a bending rigidity. Lipid bilayer membranes of vesicles can be stretched or compressed by osmotic pressure; in biological cells, also the presence of a cytoskeleton can induce membrane tension. If the thickness of the interface or the membrane is small compared with its lateral extension, both can be described using two-dimensional mathematical surfaces embedded in three-dimensional space. We review recent work on the interaction of particles with interfaces and membranes. This can be micrometer-sized particles at interfaces that stabilise emulsions or form colloidosomes, as well as typically nanometer-sized particles at membranes, such as viruses, parasites, and engineered drug delivery systems. In both cases, we first discuss the interaction of single particles with interfaces and membranes, e.g. particles in external fields, non-spherical particles, and particles at curved interfaces, followed by interface-mediated interaction between two particles, many-particle interactions, interface and membrane curvature-induced phenomena, and applications.

Second order Method for Solving 3D Elasticity Equations with Complex Interfaces

PubMed Central

Wang, Bao; Xia, Kelin; Wei, Guo-Wei

2015-01-01

Elastic materials are ubiquitous in nature and indispensable components in man-made devices and equipments. When a device or equipment involves composite or multiple elastic materials, elasticity interface problems come into play. The solution of three dimensional (3D) elasticity interface problems is significantly more difficult than that of elliptic counterparts due to the coupled vector components and cross derivatives in the governing elasticity equation. This work introduces the matched interface and boundary (MIB) method for solving 3D elasticity interface problems. The proposed MIB elasticity interface scheme utilizes fictitious values on irregular grid points near the material interface to replace function values in the discretization so that the elasticity equation can be discretized using the standard finite difference schemes as if there were no material interface. The interface jump conditions are rigorously enforced on the intersecting points between the interface and the mesh lines. Such an enforcement determines the fictitious values. A number of new techniques has been developed to construct efficient MIB elasticity interface schemes for dealing with cross derivative in coupled governing equations. The proposed method is extensively validated over both weak and strong discontinuity of the solution, both piecewise constant and position-dependent material parameters, both smooth and nonsmooth interface geometries, and both small and large contrasts in the Poisson’s ratio and shear modulus across the interface. Numerical experiments indicate that the present MIB method is of second order convergence in both L∞ and L2 error norms for handling arbitrarily complex interfaces, including biomolecular surfaces. To our best knowledge, this is the first elasticity interface method that is able to deliver the second convergence for the molecular surfaces of proteins.. PMID:25914422

Affinity of the interface between hydroxyapatite (0001) and titanium (0001) surfaces: a first-principles investigation.

PubMed

Sun, Jin P; Dai, Jianhong; Song, Yan; Wang, You; Yang, Rui

2014-12-10

A basic understanding of the affinity between the hydroxyapatite (HA) and α-Ti surfaces is obtained through electronic structure calculations by first-principles method. The surface energies of HA(0001), HA (011̅0), HA (101̅1), and Ti(0001) surfaces have been calculated. The HA(0001) presents the most thermodynamically stable of HA. The HA/Ti interfaces were constructed by two kinds of interface models, the single interface (denoted as SI) and the double-interface (denoted as DI). Two methods, the full relaxation and the UBER, were applied to determine the interfacial separation and the atomic arrangement in the interfacial zone. The works of adhesion of interfaces with various stoichiometric HA surfaces were evaluated. For the HA(0001)/Ti(0001) interfaces, the work of adhesion is strongly dependent on the chemical environment of the HA surface. The values are -2.33, -1.52, and -0.80 J/m(2) for the none-, single-, and double-Ca terminated HA/Ti interfaces, respectively. The influence of atomic relaxation on the work of adhesion and interface separation is discussed. Full relaxation results include -1.99 J/m(2) work of adhesion and 0.220 nm separation between HA and Ti for the DI of 1-Ca-HA/Ti interface, while they are -1.14 J/m(2) and 0.235 nm by partial relaxation. Analysis of electronic structure reveals that charge transfer between HA and Ti slabs occurs during the formation of the HA/Ti interface. The transfer generates the Ti-O or Ti-Ca bonds across the interface and drives the HA/Ti interface system to metallic characteristic. The energetically favorable interfaces are formed when the outmost layer of HA comprises more O atoms at the interface.

Study of hydrogen in phthalocyanine semiconductors using muSR technique =

NASA Astrophysics Data System (ADS)

Duarte, Joao Pedro Piroto Pereira

Este trabalho apresenta um estudo experimental dos semicondutores organicos Ftalocianina (H2Pc), Ftalocianina de Zinco (ZnPc) e Ftalocianina de Cobre (CuPc) por tecnicas de µSR, tendo-se obtido informacao detalhada sobre a estrutura electronica dos estados de carga formados pelo muao positivo nos tres compostos, e sobre as interaccoes dinamicas a que esses estados se encontram sujeitos. Os resultados do estudo indicam que nas ftalocianias com caracter nao magneticas H2Pc e ZnPc se da a formacao de tres radicais muonicos paramagneticos distintos. A estrutura hiperfina destes radicais, referidos como estados I, II e III, foi caracterizada atraves da medida dos parametros de acoplamento hipefino em conjunto com a parameterizacao da sua dependencia com a temperatura. Uma quarta componente paramagnetica do sinal µSR foi tambem identificada, mas sobre a qual nao foi possivel retirar conclusoes definitivas quanto a sua origem. Verificou-se que os parametros de acoplamento hiperfino isotropicos dos tres estados identificados se encontram numa regiao de valores entre os 100 e os 150MHz para os estados I e II, enquanto que para o estado III esta quantidade toma valores em torno de 10 MHz. A estrutura electronica de todos os estados possui simetria axial, caracterizada por parametros dipolares de cerca de 15MHz para os estados I e II, e 20MHz para o estado III. A origem dos estados I e II foi determinada como sendo devida a adicao de muonio a uma das ligacoes duplas existentes nos aneis benzenicos da periferia das moleculas de ftalocianina recorrendo a calculos de estrutura electronica, tendo-se verificado a existencia de um acoplamento entre a interaccao hiperfina desses estados e modos vibracionais desses aneis. A problematica da localizacao do estado III tambem foi abordada, tomando-se como hipotese mais provavel uma posicao intersticial entre duas moleculas de ftalocianina. O estudo das interaccoes dinamicas de spin destes tres estados revelou que o estado III esta sujeito a um fenomeno de spin exchange, originado pela colisao com portadores de carga presentes no material. A taxa de spin-flip relativa a esta interaccao foi deduzida a partir de medidas µSR em geometria de campo longitudinal, tendo sida determinada a barreira energetica existente para a difusao de portadores de carga entre moleculas de ftalocianina localizadas dentro da mesma estrutura colunar tanto na H2Pc, como na ZnPc. Por fim, o sinal µSR da ftalocianina com caracter magnetico CuPc foi tambem caracterizado. Foram identificadas duas componentes de caracter aparentemente diamagnetico com taxas de relaxacao separadas por cerca de duas ordens de grandeza, atribuidas a duas configuracoes distintas para o emparelhamento entre o electrao do radical muonico, e o electrao com spin desemparelhado localizado no atomo de cobre. Os dois emparelhamentos diferentes geram um ambiente puramente diamagnetico para o muao, o que origina a componente de relaxacao lenta, e uma configuracao na qual existe uma densidade de spin flutuante na posicao do muao, responsavel pela componente de relaxacao elevada.

Is the Dark Side of the Moon Ever Illuminated by the Sun? (Breton Title: O Lado Escuro da Lua Nunca Apanha Sol?) El Lado Oscuro de la Luna Nunca Toma Sol?

NASA Astrophysics Data System (ADS)

Giovannini, Odilon; Pellenz, Daiana; Catelli, Francisco

2014-07-01

This work presents the elaboration of an answer to the question "Is the dark side of the moon ever illuminated by the sun?", in which issues related to the students' conceptions, how they arise, and the core elements that constitute a "good answer" are considered. These issues are initially elaborated from a literature review of the research in the field; then, and also based on this review, a didactic model that involves the relative motions of the Earth - Moon - Sun system is proposed. A description of the application of this model in a learning environment within middle school students is described. This work confirms the students' initial concepts described in the literature; on the other hand, the questions asked by students during the activity provide evidence that meaningful learning, at least to some degree, has occurred. Este trabalho apresenta a elaboração de uma resposta à pergunta "O lado escuro da Lua nunca apanha sol?" na qual são consideradas questões relacionadas às concepções iniciais dos alunos, de onde elas surgem e os elementos centrais que constituem uma "boa resposta". Essas questões são tratadas, inicialmente, a partir de uma revisão da literatura sobre pesquisas na área e, em seguida, também com base nessa revisão, um objeto modelo didático que envolve os movimentos relativos do sistema Terra - Lua - Sol é proposto. Uma descrição detalhada da aplicação deste modelo em um ambiente de aprendizagem com alunos do ensino fundamental é relatada. As concepções iniciais apresentadas na literatura se confirmam e os questionamentos feitos pelos estudantes por ocasião da aplicação do modelo fornecem indícios de que uma aprendizagem significativa, pelo menos em algum grau, ocorreu. El artículo se presenta el desarrollo de una respuesta a la pregunta "¿El lado oscuro de la luna nunca toma sol?", en la que se consideran algunas cuestiones vinculadas que se refieren a las concepciones iniciales de los estudiantes, dónde surgen y los elementos básicos que componen una "respuesta correcta". Estas cuestiones se tratan inicialmente a partir de una revisión bibliográfica de la investigación en el área; seguidamente, y también sobre la base de ésta revisión, se propone un modelo didáctico que ejemplifica los movimientos relativos del sistema Tierra - Luna - Sol. Se describe a continuación una aplicación de este modelo en un entorno de aprendizaje con alumnos del ciclo primario. Los conceptos iniciales presentados en la literatura se confirman y las cuestiones planteadas por los estudiantes durante la implementación del modelo proporcionan evidencia de que se ha producido un aprendizaje significativo, al menos en cierta medida.

Systems and methods for compensating for electrical converter nonlinearities

DOEpatents

Perisic, Milun; Ransom, Ray M.; Kajouke, Lateef A.

2013-06-18

Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module coupled between the input interface and the output interface, and a control module. The control module determines a duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface. The control module determines an input power error at the input interface and adjusts the duty cycle control value in a manner that is influenced by the input power error, resulting in a compensated duty cycle control value. The control module operates switching elements of the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value.

Recrystallization characteristics and interfacial oxides on the compression bonding interface

NASA Astrophysics Data System (ADS)

Xie, Bijun; Sun, Mingyue; Xu, Bin; Li, Dianzhong

2018-05-01

Up to now, the mechanism of interface bonding is still not fully understood. This work presents interfacial characteristics of 316LN stainless steel bonding joint after cold compression bonding with subsequent annealing. EBSD analysis shows that fine recrystallization grains preferentially appear near the bonding interface and grow towards both sides of the interface. Transmission electron microscopy reveals that initial cold compression bonding disintegrates the native oxide scales and brings pristine metal from both sides of the interface come into intimate contact, while the broken oxide particles are remained at the original interface. The results indicate that partial bonding can be achieved by cold compression bonding with post-annealing treatment and recrystallization firstly occurs along the bonding interface. However, the interfacial oxides impede the recrystallization grains step over the interface and hinder the complete healing of the bonding interface.

Bio-inspired Edible Superhydrophobic Interface for Reducing Residual Liquid Food.

PubMed

Li, Yao; Bi, Jingran; Wang, Siqi; Zhang, Tan; Xu, Xiaomeng; Wang, Haitao; Cheng, Shasha; Zhu, Bei-Wei; Tan, Mingqian

2018-03-07

Significant wastage of residual liquid food, such as milk, yogurt, and honey, in food containers has attracted great attention. In this work, a bio-inspired edible superhydrophobic interface was fabricated using U.S. Food and Drug Administration-approved and edible honeycomb wax, arabic gum, and gelatin by a simple and low-cost method. The bio-inspired edible superhydrophobic interface showed multiscale structures, which were similar to that of a lotus leaf surface. This bio-inspired edible superhydrophobic interface displayed high contact angles for a variety of liquid foods, and the residue of liquid foods could be effectively reduced using the bio-inspired interface. To improve the adhesive force of the superhydrophobic interface, a flexible edible elastic film was fabricated between the interface and substrate material. After repeated folding and flushing for a long time, the interface still maintained excellent superhydrophobic property. The bio-inspired edible superhydrophobic interface showed good biocompatibility, which may have potential applications as a functional packaging interface material.

First-principles based calculation of the macroscopic α/β interface in titanium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dongdong; Key Lab of Nonferrous Materials of Ministry of Education, Central South University, Changsha 410083; Zhu, Lvqi

2016-06-14

The macroscopic α/β interface in titanium and titanium alloys consists of a ledge interface (112){sub β}/(01-10){sub α} and a side interface (11-1){sub β}/(2-1-10){sub α} in a zig-zag arrangement. Here, we report a first-principles study for predicting the atomic structure and the formation energy of the α/β-Ti interface. Both component interfaces were calculated using supercell models within a restrictive relaxation approach, with various staking sequences and high-symmetry parallel translations being considered. The ledge interface energy was predicted as 0.098 J/m{sup 2} and the side interface energy as 0.811 J/m{sup 2}. By projecting the zig-zag interface area onto the macroscopic broad face, the macroscopicmore » α/β interface energy was estimated to be as low as ∼0.12 J/m{sup 2}, which, however, is almost double the ad hoc value used in previous phase-field simulations.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimura, Tomoharu; Yamada, Hirofumi, E-mail: h-yamada@kuee.kyoto-u.ac.jp; Kobayashi, Kei

The device performances of organic thin film transistors are often limited by the metal–organic interface because of the disordered molecular layers at the interface and the energy barriers against the carrier injection. It is important to study the local impedance at the interface without being affected by the interface morphology. We combined frequency modulation atomic force microscopy with scanning impedance microscopy (SIM) to sensitively measure the ac responses of the interface to an ac voltage applied across the interface and the dc potential drop at the interface. By using the frequency-modulation SIM (FM-SIM) technique, we characterized the interface impedance ofmore » a Pt electrode and a single pentacene grain as a parallel circuit of a contact resistance and a capacitance. We found that the reduction of the contact resistance was caused by the reduction of the energy level mismatch at the interface by the FM-SIM measurements, demonstrating the usefulness of the FM-SIM technique for investigation of the local interface impedance without being affected by its morphology.« less

Parameters Identification of Interface Friction Model for Ceramic Matrix Composites Based on Stress-Strain Response

NASA Astrophysics Data System (ADS)

Han, Xiao; Gao, Xiguang; Song, Yingdong

2017-10-01

An approach to identify parameters of interface friction model for Ceramic Matrix composites based on stress-strain response was developed. The stress distribution of fibers in the interface slip region and intact region of the damaged composite was determined by adopting the interface friction model. The relation between maximum strain, secant moduli of hysteresis loop and interface shear stress, interface de-bonding stress was established respectively with the method of symbolic-graphic combination. By comparing the experimental strain, secant moduli of hysteresis loop with computation values, the interface shear stress and interface de-bonding stress corresponding to first cycle were identified. Substituting the identification of parameters into interface friction model, the stress-strain curves were predicted and the predicted results fit experiments well. Besides, the influence of number of data points on identifying the value of interface parameters was discussed. And the approach was compared with the method based on the area of hysteresis loop.

Lattice structures and electronic properties of CIGS/CdS interface: First-principles calculations

NASA Astrophysics Data System (ADS)

Tang, Fu-Ling; Liu, Ran; Xue, Hong-Tao; Lu, Wen-Jiang; Feng, Yu-Dong; Rui, Zhi-Yuan; Huang, Min

2014-07-01

Using first-principles calculations within density functional theory, we study the atomic structures and electronic properties of the perfect and defective (2VCu+InCu) CuInGaSe2/CdS interfaces theoretically, especially the interface states. We find that the local lattice structure of (2VCu+InCu) interface is somewhat disorganized. By analyzing the local density of states projected on several atomic layers of the two interfaces models, we find that for the (2VCu+InCu) interface the interface states near the Fermi level in CuInGaSe2 and CdS band gap regions are mainly composed of interfacial Se-4p, Cu-3d and S-3p orbitals, while for the perfect interface there are no clear interface states in the CuInGaSe2 region but only some interface states which are mainly composed of S-3p orbitals in the valance band of CdS region.

Systems engineering interfaces: A model based approach

NASA Astrophysics Data System (ADS)

Fosse, E.; Delp, C. L.

The engineering of interfaces is a critical function of the discipline of Systems Engineering. Included in interface engineering are instances of interaction. Interfaces provide the specifications of the relevant properties of a system or component that can be connected to other systems or components while instances of interaction are identified in order to specify the actual integration to other systems or components. Current Systems Engineering practices rely on a variety of documents and diagrams to describe interface specifications and instances of interaction. The SysML[1] specification provides a precise model based representation for interfaces and interface instance integration. This paper will describe interface engineering as implemented by the Operations Revitalization Task using SysML, starting with a generic case and culminating with a focus on a Flight System to Ground Interaction. The reusability of the interface engineering approach presented as well as its extensibility to more complex interfaces and interactions will be shown. Model-derived tables will support the case studies shown and are examples of model-based documentation products.

Connecting Interface Structure to Energy Level Alignment at Aqueous Semiconductor Interfaces

NASA Astrophysics Data System (ADS)

Hybertsen, Mark

Understanding structure-function relationships at aqueous semiconductor interfaces presents fundamental challenges, including the discovery of the key interface structure motifs themselves. Important examples include the alignment of electrochemical redox levels with the semiconductor band edges and the identification of catalytic active sites. We have developed a multistep approach, initially demonstrated for GaN, ZnO and their alloys, motivated by measured high efficiency for photocatalytic water oxidation. The interface structure is simulated using ab initio molecular dynamics (AIMD). The calculated, average interface dipole is combined with the GW approach from many-body perturbation theory to calculate the energy level alignment between the semiconductor band edges and the centroid of the occupied 1b1 energy level of water and thus, the electrochemical levels. Cluster models are used to study reaction pathways. The emergent interface motif is the full (GaN) or partial (ZnO) dissociated interface water layer. Here I will focus on the aqueous interfaces to the stable TiO2 anatase (101) and rutile (110) facets. The AIMD calculations reveal interface water dissociation and reassociation processes through distinct pathways: one direct at the interface and the other via a spectator water molecule from the hydration layer. Comparisons between the two interfaces shows that the energy landscape for these pathways depends on the local hydrogen bonding patterns and the interplay with the interface template. Combined results from different initial conditions and AIMD temperatures demonstrate a partially dissociated interface water layer in both cases. Specifically for rutile, structure and the GW-based analysis of the interface energy level alignment agree with experiment. Finally, hole localization at different interface structure motifs will be discussed. Work performed in collaboration with J. Lyons, N. Kharche, M. Ertem and J. Muckerman, done in part at the CFN, which is a U.S. DOE Office of Science Facility, at BNL under Contract No. DE-SC0012704 and with resources from NERSC under Contract No. DE-AC02-05CH11231.

Steered Molecular Dynamics Simulations Predict Conformational Stability of Glutamate Receptors.

PubMed

Musgaard, Maria; Biggin, Philip C

2016-09-26

The stability of protein-protein interfaces can be essential for protein function. For ionotropic glutamate receptors, a family of ligand-gated ion channels vital for normal function of the central nervous system, such an interface exists between the extracellular ligand binding domains (LBDs). In the full-length protein, the LBDs are arranged as a dimer of dimers. Agonist binding to the LBDs opens the ion channel, and briefly after activation the receptor desensitizes. Several residues at the LBD dimer interface are known to modulate desensitization, and conformational changes around these residues are believed to be involved in the state transition. The general hypothesis is that the interface is disrupted upon desensitization, and structural evidence suggests that the disruption might be substantial. However, when cross-linking the central part of this interface, functional data suggest that the receptor can still undergo desensitization, contradicting the hypothesis of major interface disruption. Here, we illustrate how opening the dimer interface using steered molecular dynamics (SMD) simulations, and analyzing the work values required, provides a quantitative measure for interface stability. For one subtype of glutamate receptors, which is regulated by ion binding to the dimer interface, we show that opening the interface without ions bound requires less work than with ions present, suggesting that ion binding indeed stabilizes the interface. Likewise, for interface mutants with longer-lived active states, the interface is more stable, while the work required to open the interface is reduced for less active mutants. Moreover, a cross-linked mutant can still undergo initial interface opening motions similar to the native receptor and at similar energetic cost. Thus, our results support that interface opening is involved in desensitization. Furthermore, they provide reconciliation of apparently opposing data and demonstrate that SMD simulations can give relevant biological insight into longer time scale processes without the need for expensive calculations.

Lineage diversification of fringe-toed lizards (Phrynosomatidae: Uma notata complex) in the Colorado Desert: Delimiting species in the presence of gene flow

USGS Publications Warehouse

Gottscho, Andrew D.; Wood, Dustin A.; Vandergast, Amy; Lemos Espinal, Julio A.; Gatesy, John; Reeder, Tod

2017-01-01

Multi-locus nuclear DNA data were used to delimit species of fringe-toed lizards of theUma notata complex, which are specialized for living in wind-blown sand habitats in the deserts of southwestern North America, and to infer whether Quaternary glacial cycles or Tertiary geological events were important in shaping the historical biogeography of this group. We analyzed ten nuclear loci collected using Sanger sequencing and genome-wide sequence and single-nucleotide polymorphism (SNP) data collected using restriction-associated DNA (RAD) sequencing. A combination of species discovery methods (concatenated phylogenies, parametric and non-parametric clustering algorithms) and species validation approaches (coalescent-based species tree/isolation-with-migration models) were used to delimit species, infer phylogenetic relationships, and to estimate effective population sizes, migration rates, and speciation times. Uma notata, U. inornata, U. cowlesi, and an undescribed species from Mohawk Dunes, Arizona (U. sp.) were supported as distinct in the concatenated analyses and by clustering algorithms, and all operational taxonomic units were decisively supported as distinct species by ranking hierarchical nested speciation models with Bayes factors based on coalescent-based species tree methods. However, significant unidirectional gene flow (2NM >1) from U. cowlesi and U. notata into U. rufopunctata was detected under the isolation-with-migration model. Therefore, we conservatively delimit four species-level lineages within this complex (U. inornata, U. notata, U. cowlesi, and U. sp.), treating U. rufopunctata as a hybrid population (U. notata x cowlesi). Both concatenated and coalescent-based estimates of speciation times support the hypotheses that speciation within the complex occurred during the late Pleistocene, and that the geological evolution of the Colorado River delta during this period was an important process shaping the observed phylogeographic patterns.

Self-referencing thermometry in the nanoscale =

NASA Astrophysics Data System (ADS)

Brites, Carlos Antonio Delgado Sousa

Na ultima decada emergiu uma linha de investigacao muito activa em termometros nao invasivos e precisos que possam determinar temperatura a escala nanometrica. Esta investigacao foi fortemente estimulada pelas numerosas solicitacoes da nanotecnologia e da biomedicina, por exemplo. Uma das abordagens mais promissoras propoe o uso de ioes trivalentes de lantanideos que apresenta propriedades fotoluminescentes que dependem da temperatura. Neste trabalho demonstra-se que esta tecnica combina as vantagens de te um limite de deteccao de 0.5 graus com sensibilidade ate 4.5 % K-1. Este termometro molecular pode ser processado em filmes finos ou nanoparticulas, abrindo os campos de aplicacao a diferentes utilizacoes. As nanoparticulas de silica produzidas sao caracterizadas na presenca e na ausencia de ioes lantanideos. Sem o metal, as nanoparticulas de APTES/TEOS demonstram ser luminescentes sob excitacao UV sem necessidade de utilizar qualquer tratamento termico. O rendimento quantico de emissao depende apenas da proporcao dos silanos e pode atingir o valor de 0.15 +/- 0.02. A co-dopagem destas nanoparticulas com Eu3+ e Tb3+ permite obter sondas com resposta raciometrica, com a possibilidade de ajustar a gama de temperaturas de operacao e a sensibilidade, via desenho inteligente da matriz de suporte e dos ligandos de beta-dicetona que estao coordenados ao iao metalico. Quando processados como filmes, este termometro permite o mapeamento de temperaturas com resolucao espacial 1.8 mum. A racionalizacao da dependencia de temperatura e uma ferramenta util para desenvolver termometros que operam em gamas de temperatura especificos (e.g. gama de temperatura fisiologica, 290-340 K) com sensibilidade acima de 0.5 % K-1. A combinacao de esforcos de um grande numero de diversas disciplinas ira previsivelmente permitir o surgimento de termometros moleculares novos e sofisticados, preenchendo os principais requisitos das nanociencias.

Espectroscopia multi-objeto e imageamento de Abell 586 com GMOS - o estado dinâmico de um aglomerado de galáxias com arcos gravitacionais

NASA Astrophysics Data System (ADS)

Cypriano, E. S.; Sodré, L., Jr.; Kneib, J.-P.; Campusano, L.

2003-08-01

Nesse trabalho é apresentado um estudo do conteúdo de massa do aglomerado de galáxias A586 (z = 0.171) bem como sua distribuição espacial. Isso foi feito a partir de dados de espectroscopia multi-objeto e imageamento obtidos com o instrumento GMOS acoplado ao telescópio Gemini-Norte. A massa desse aglomerado foi estudada a partir da posição dos seus arcos gravitacionais (lentes fortes), da medida estatística da distorção na forma das galáxias de fundo (lentes fracas) e através da dispersão de velocidades de uma amostra de cerca de 30 galáxias pertencentes ao aglomerado (teorema do virial). Os dois primeiros métodos não dependem do estado dinâmico do aglomerado, enquanto que o terceiro sim. Desse modo, comparando seus resultados pode-se estimar o grau de relaxamento desse sistema. Dados de raios X presentes na literatura também serão incluídos nessa análise. Nossos resultados preliminares a partir das técnicas de lentes fracas, mostram que, supondo que a distribuição de massa desse aglomerado seja a de uma esfera isotérmica, espera-se que ele apresente uma dispersão de velocidades de 1330+/-78 km s-1, em contradicao com medidas similares feitas por Dahle et al. 2002 que encontram valores tão altos quanto 1680 km s-1. Já o estudo dinâmico resultou numa dispersão de velocidades de ~950 km s-1.

Sobre o uso das séries de Puiseux em mecanica celeste

NASA Astrophysics Data System (ADS)

Miloni, O. I.

2003-08-01

Neste trabalho é apresentada uma demonstração do uso dos diferentes desenvolvimentos em séries para as equações de perturbação em Mecânica Celeste no marco Hamiltoniano. Em trabalhos clássicos como os de Poincaré (Poincaré, 1893) por exemplo, já esta planteado o uso de potências não inteiras no pequeno parâmetro, o que evidencia a não analiticidade das funções quando uma ressonância ocorre. Nestes trabalhos os desenvolvimentos são na raíz quadrada da massa de Júpiter (o pequeno parâmetro). Mais recentemente (Ferraz-Mello, 1985) outros tipos de desenvolvimentos foram aplicados modificando substancialmente as ordens de grandeza e a velocidade de convergência das séries. Com esta abordagem, os desenvolvimentos foram expressados em termos da raíz cúbica do pequeno parâmetro. Neste trabalho apresentamos um enfoque geral, onde os diferentes tipos de desenvolvimentos em séries de Puiseux (Valiron, 1950) são obtidos a partir da aplicação de Teorema de Preparação de Weierstrass (Goursat, 1916) considerando a equação de Hamilton-Jacobi como uma equação algébrica. Os resultados são aplicados ao problema restrito dos três corpos em ressonância de primeira ordem e, dependendo da grandeza da excentricidade do asteróide em relação à de Júpiter, obtemos os diferentes desenvolvimentos, em raíz quadrada ou raíz cúbica da massa de Júpiter.

The Adequacy of the Q Methodology for Clinical Validation of Nursing Diagnoses Related to Subjective Foci.

PubMed

Miguel, Susana; Caldeira, Sílvia; Vieira, Margarida

2018-04-01

This article describes the adequacy of the Q methodology as a new option for the validation of nursing diagnoses related to subjective foci. Discussion paper about the characteristics of the Q methodology. This method has been used in nursing research particularly related to subjective concepts and includes both a quantitative and qualitative dimension. The Q methodology seems to be an adequate and innovative method for the clinical validation of nursing diagnoses. The validation of nursing diagnoses related to subjective foci using the Q methodology could improve the level of evidence and provide nurses with clinical indicators for clinical reasoning and for the planning of effective interventions. Descrever a adequação da metodologia Q como uma nova opção para a validação clínica de diagnósticos de enfermagem relacionados com focos subjetivos. MÉTODOS: Artigo de discussão sobre as características da metodologia Q. Este método tem sido utilizado na pesquisa em enfermagem relacionada com conceitos subjetivos e inclui em simultâneo uma vertente qualitativa e quantitativa. CONCLUSÕES: A metodologia Q parece ser uma opção metodológica adequada para a validação clínica de diagnósticos de enfermagem. IMPLICAÇÕES PARA A PRÁTICA: A utilização da metodologia Q na validação clínica de diagnósticos de enfermagem relacionados com focos subjetivos pode melhorar o nível e evidência e facilitar o raciocínio clínico dos enfermeiros, ao providenciar indicadores clínicos também necessários ao desenvolvimento de intervenções efetivas. © 2016 NANDA International, Inc.

Survey of period variations of superhumps in SU UMa-type dwarf novae. VIII. The eighth year (2015-2016)

NASA Astrophysics Data System (ADS)

Kato, Taichi; Hambsch, Franz-Josef; Monard, Berto; Vanmunster, Tonny; Maeda, Yutaka; Miller, Ian; Itoh, Hiroshi; Kiyota, Seiichiro; Isogai, Keisuke; Kimura, Mariko; Imada, Akira; Tordai, Tamás; Akazawa, Hidehiko; Tanabe, Kenji; Otani, Noritoshi; Ogi, Minako; Ando, Kazuko; Takigawa, Naoki; Dubovsky, Pavol A.; Kudzej, Igor; Shugarov, Sergey Yu.; Katysheva, Natalia; Golysheva, Polina; Gladilina, Natalia; Chochol, Drahomir; Starr, Peter; Kasai, Kiyoshi; Pickard, Roger D.; de Miguel, Enrique; Kojiguchi, Naoto; Sugiura, Yuki; Fukushima, Daiki; Yamada, Eiji; Uto, Yusuke; Kamibetsunawa, Taku; Tatsumi, Taiki; Takeda, Nao; Matsumoto, Katsura; Cook, Lewis M.; Pavlenko, Elena P.; Babina, Julia V.; Pit, Nikolaj V.; Antonyuk, Oksana I.; Antonyuk, Kirill A.; Sosnovskij, Aleksei A.; Baklanov, Aleksei V.; Kafka, Stella; Stein, William; Voloshina, Irina B.; Ruiz, Javier; Sabo, Richard; Dvorak, Shawn; Stone, Geoff; Andreev, Maksim V.; Antipin, Sergey V.; Zubareva, Alexandra M.; Zaostrojnykh, Anna M.; Richmond, Michael; Shears, Jeremy; Dubois, Franky; Logie, Ludwig; Rau, Steve; Vanaverbeke, Siegfried; Simon, Andrei; Oksanen, Arto; Goff, William N.; Bolt, Greg; Dębski, Bartłomiej; Kochanek, Christopher S.; Shappee, Benjamin; Stanek, Krzysztof Z.; Prieto, José L.; Stubbings, Rod; Muyllaert, Eddy; Hiraga, Mitsutaka; Horie, Tsuneo; Schmeer, Patrick; Hirosawa, Kenji

2016-08-01

Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 128 SU UMa-type dwarf novae observed mainly during the 2015-2016 season and characterized these objects. The data have improved the distribution of orbital periods, the relation between the orbital period and the variation of superhumps, and the relation between period variations and the rebrightening type in WZ Sge-type objects. Coupled with new measurements of mass ratios using growing stages of superhumps, we now have a clearer and statistically greatly improved evolutionary path near the terminal stage of evolution of cataclysmic variables. Three objects (V452 Cas, KK Tel, and ASASSN-15cl) appear to have slowly growing superhumps, which is proposed to reflect the slow growth of the 3 : 1 resonance near the stability border. ASASSN-15sl, ASASSN-15ux, SDSS J074859.55+312512.6, and CRTS J200331.3-284941 are newly identified eclipsing SU UMa-type (or WZ Sge-type) dwarf novae. ASASSN-15cy has a short (˜0.050 d) superhump period and appears to belong to EI Psc-type objects with compact secondaries having an evolved core. ASASSN-15gn, ASASSN-15hn, ASASSN-15kh, and ASASSN-16bu are candidate period bouncers with superhump periods longer than 0.06 d. We have newly obtained superhump periods for 79 objects and 13 orbital periods, including periods from early superhumps. In order that future observations will be more astrophysically beneficial and rewarding to observers, we propose guidelines on how to organize observations of various superoutbursts.

Determination of tissue hypoxia by physicochemical approach in premature anemia.

PubMed

Özdemir, Zeliha; Törer, Birgin; Hanta, Deniz; Cetinkaya, Bilin; Gulcan, Hande; Tarcan, Aylin

2017-10-01

Anemia is a common problem in premature infants and its most rapid and effective therapy is erythrocyte transfusion. However, owing to inherent risks of transfusion in this population, transfusions should be administered only when adequate oxygen delivery to tissues is impaired. The aim of this study was to determine tissue acid levels using Stewart method in an attempt to evaluate the tissue oxygenation level and thereby the accuracy of transfusion timing. This study included 47 infants delivered at gestational age below 34 weeks who required erythrocyte transfusion for premature anemia. Strong ion gap (SIG), unmeasurable anions (UMA), tissue acid levels (TA), and Cl/Na ratios were calculated before and after transfusion. The mean birth weight and gestational age of the study population were 1210 ± 365 g and 29.2 ± 2.7 weeks, respectively. Tissue acid levels were increased (TA ≥ 4) and tissue hypoxia developed in 10 (16.6%) of 60 erythrocyte transfusions administered according to the restrictive transfusion approach. The patients were divided into two groups according to tissue acid levels as low (<4) and high (≥4) tissue acid groups. The group with tissue hypoxia (TA ≥ 4) had significantly higher UMA levels but a significantly lower Cl/Na ratio; and UMA levels decreased and Cl/Na ratio increased after transfusion in this group. Tissue hypoxia secondary to anemia was shown to be improved by erythrocyte transfusion. The results of the present study suggest that the determination of the level of tissue hypoxia by the Stewart approach may be an alternative to restrictive transfusion guidelines for timing of transfusion in premature anemia. It also showed that a low Cl/Na ratio can be used as a simple marker of tissue hypoxia. Copyright © 2017. Published by Elsevier B.V.

Optical Flares and a Long-lived Dark Spot on a Cool Shallow Contact Binary

NASA Astrophysics Data System (ADS)

Qian, S.-B.; Wang, J.-J.; Zhu, L.-Y.; Snoonthornthum, B.; Wang, L.-Z.; Zhao, E. G.; Zhou, X.; Liao, W.-P.; Liu, N.-P.

2014-05-01

W UMa-type stars are contact systems where both cool components fill the critical Roche lobes and share a common convective envelope. Long and unbroken time-series photometry is expected to play an important role in their origin and activity. The newly discovered short-period W UMa-type star, CSTAR 038663, was monitored continuously by Chinese Small Telescope ARray (CSTAR) in Antarctica during the winters of 2008 and 2010. There were 15 optical flares recorded in the i band during the winter of 2010. This was the first time such flares were detected from a W UMa-type star. By analyzing the nearly unbroken photometric data from 2008, it is discovered that CSTAR 038663 is a W-type shallow contact binary system (f = 10.6(± 2.9)%) with a high mass ratio of q = 1.12(± 0.01), where the less massive component is slightly hotter than the more massive one. The asymmetric light curves are explained by the presence of a dark spot on the more massive component. Its temperature is about 800 K lower than the stellar photosphere and it covers 2.1% of the total photospheric surface. The lifetime of the dark spot is longer than 116 days. Using 725 eclipse times, we found that the observed-calculated (O-C) curve may show a cyclic variation that is explained by the presence of a close-in third body. Both the shallow contact configuration and the extremely high mass ratio suggest that CSTAR 038663 is presently evolving into a contact system with little mass transfer. The formation and evolution is driven by the loss of angular momentum via magnetic braking, and the close-in companion star is expected to play an important role, removing angular momentum from the central eclipsing binary.

A Utilização da Astronomia como Tema Interdisciplinar e Aplicações de Objetos de Aprendizagem

NASA Astrophysics Data System (ADS)

da Silva, L. A.; Voelzke, M. R.

2008-09-01

Este trabalho visa analisar a possibilidade de relacionar conteúdos aplicados no ensino fundamental e médio de forma interdisciplinar por intermédio da astronomia, com a intervenção de objetos de aprendizagem que possam integrar as disciplinas e a utilização de recursos tecnológicos. Em uma pesquisa prévia com 20 professores de uma escola estadual situada na cidade de Guarulhos foi observado que apenas 25% dos professores utilizam algum recurso tecnológico para o desenvolvimento de conteúdos pertinentes à sua disciplina, tais como sites e softwares educativos, sendo que a maioria absoluta continua ensinando apenas com livros didáticos. A maior parte dos professores apresenta dificuldades em trabalhar sua disciplina de forma interdisciplinar, ou seja, 75% dos professores preferem aplicar os conteúdos seguindo uma hierarquia linear de tópicos, evitando a discussão de temas que de alguma forma estão relacionados. A astronomia pode vir à fascinar o ser humano e despertar sua curiosidade promovendo um maior interesse no aprendizado, podendo favorecer análises interdisciplinares de forma lógica e objetiva, desta forma colocar a astronomia como tema motivador interdisciplinar, pode ser relevante no que se refere ao distanciamento da fragmentação dos conteúdos. No Estado de São Paulo, a implantação da proposta curricular no ensino fundamental e médio mostra claramente a inserção da astronomia na maior parte das séries, principalmente na 6ª série em que todo o bimestre se fala de astronomia.

Fundamental parameters of BE UMa revised

NASA Astrophysics Data System (ADS)

Shimanskii, V. V.; Borisov, N. V.; Pozdnyakova, S. A.; Bikmaev, I. F.; Vlasyuk, V. V.; Sakhibullin, N. A.; Spiridonova, O. I.

2008-07-01

We have determined a complete set of parameters for the young pre-cataclysmic variable BE UMa from a comprehensive photometric and spectroscopic analysis using model atmospheres. Our precise photometry and spectroscopy were acquired with the 6-m telescope and Zeiss-1000 telescope of the Special Astrophysical Observatory and the 1.5-m Russian-Turkish telescope at a wide range of orbital phases, including times of primary eclipses.We performed a detailed identification of emission lines of ten elements. At phases of minimum brightness, the spectra reveal absorption lines and molecular bands formed in the secondary’s atmosphere, whose effective temperature was determined to be T {/eff (2)} = 4750 ± 150 K. We have studied the radial-velocity curves of the cool star using lines of various elements. All the curves exhibit the previously predicted distortions due to reflection effects in the close binary. The derived component-mass ratio is q = 0.43 ± 0.09, and the component masses are M 1 = 0.59 ± 0.07 M ⊙ and M 2 = 0.25 ± 0.08 M ⊙. We analyzed the light curves using model atmospheres for irradiated stars; all the parameters of BE UMa were refined. We demonstrate the validity of our modeling of the binary’s spectra at phases of brightness maximum, which provides a good description of the observed intensities of most lines of heavy elements. The abundances of helium and several light elements (C, N, O, Ne, Mg) in the atmosphere of the cool star are probably higher than the solar values. We conclude that the physical characteristics of the primary are in good agreement with evolutionary tracks for planetary-nebula nuclei, and that the secondary is overluminous by a factor of 30 compared to main-sequence stars of the same mass.

Mass intrusion beneath Kilauea Volcano, Hawaii, constraints from gravity and geodetic measurements (1975-2008)

NASA Astrophysics Data System (ADS)

Bagnardi, M.; Eggers, A.; Battaglia, M.; Poland, M.; Johnson, D.

2008-12-01

Since January 3 1983, Kilauea Volcano, Hawaii, has erupted almost continuously from vents on the volcano's east rift zone. On March 19, 2008, an explosion at Halema'uma'u Crater, within the summit caldera of Kilauea, marked the opening of a second eruptive vent on the volcano. The east rift vent at Pu'u'O'o and the summit vent at Halema'uma'u continue to be active as of August 2008, marking the longest interval in Kilauea's recorded history of eruptive activity on the volcano. Four gravity surveys with a network covering Kilauea's summit area have been performed during 1975-2003. We reoccupied this 45-station network in January and July 2008 with three portable LaCoste-Romberg gravimeters (G209, G615 and EG026) using a double-looping procedure. These two most recent gravity surveys span the onset of summit eruptive activity. The micro-gravity data set, combined with existing geodetic data from leveling, GPS, EDM, and InSAR, allow us to investigate and model the shallow magma system under the summit caldera to roughly constrain its shape, position, volume change and density, and better understand its long and short term evolution. We corrected for the effect of vertical deformation on gravity data (the so-called free-air effect) using uplift measurements from annual surveys performed by the USGS Hawaiian Volcano Observatory. Preliminary analysis of this record, which covers more than 30 years, indicates a persistent positive residual gravity anomaly located at the southeast margin of Halema'uma'u Crater, very close to the location of the new summit eruptive vent. This anomaly suggests a long term mass accumulation beneath the summit caldera.

Hypertriglyceridemia: Is there a role for prophylactic apheresis? A case report.

PubMed

Francisco, Ana Rita; Gonçalves, Inês; Veiga, Fátima; Pedro, Mónica Mendes; Pinto, Fausto J; Brito, Dulce

2016-01-01

Severe hypertriglyceridemia has been consistently associated with an increased risk of cardiovascular disease and other complications, namely acute pancreatitis. We report a case of a 64 year-old woman with hypertrophic cardiomyopathy and metabolic syndrome with triglyceride level of 3260 mg/dL. Plasma exchange was performed with simultaneous medical treatment to achieve a rapid and effective lowering of triglycerides in order to prevent clinical complications. After three plasmapheresis sessions a marked reduction in triglyceride and total cholesterol levels was observed. Several cases have shown the importance of plasmapheresis in the treatment of acute pancreatitis. We intend to demonstrate the applicability of this technique as primary prophylaxis in the presence of extremely high serum triglyceridemia levels. Resumo A hipertrigliceridemia grave tem sido associada de forma consistente ao aumento do risco cardiovascular e a outras complicações, nomeadamente, pancreatite aguda. Descrevemos um caso de uma mulher de 64 anos, com miocardiopatia hipertrófica e síndrome metabólica com valor sérico de triglicerídeos de 3260 mg/dL. Foi efectuada plasmaferese e optimizado o tratamento médico para alcançar uma redução rápida e efectiva dos níveis dos triglicerídeos, prevenindo complicações clínicas. Após três sessões de plasmaferese, verificou-se uma redução marcada dos triglicerídeos e do colesterol total. Existem alguns casos descritos na literatura demonstrado a importância da plasmaferese no tratamento da pancreatite aguda em contexto de hipertrigliceridemia grave. Os autores pretendem com este caso demonstrar a aplicabilidade desta técnica em contexto de prevenção primária em doentes com níveis de triglicerídeos extremamente aumentados.

A importância da poeira e ondas de Alfvén na estabilidade de nuvens moleculares anãs

NASA Astrophysics Data System (ADS)

Falceta-Gonçalves, D.; de Juli, M. C.; Jatenco-Pereira, V.

2003-08-01

Nuvens moleculares anãs se apresentam dinamicamente estáveis, embora possuam massas muito maiores que a massa de Jeans. Por este motivo, a estabilidade destes objetos não pode ser explicada considerando-se apenas a pressão térmica. Campos magnéticos, aproximadamente uniformes e de ~mG, exercem um termo extra de pressão que sustenta a nuvem, mas somente na direção perpendicular às linhas de campo. Para a direção paralela, ondas de Alfvén geradas por turbulências no meio, por exemplo, têm sido utilizadas. Estas, sendo supostamente fracamente amortecidas, poderiam sustentar a nuvem nesta direção. Entretanto, estes meios contêm grandes quantidades de poeira carregada eletricamente. Estes grãos de poeira possuem frequências cíclotron, que podem entrar em ressonância com as ondas. Neste trabalho calculamos os efeitos que o amortecimento cíclotron da poeira teriam na propagação da onda, e consequentemente na estabilidade da nuvem. Considerando um fluxo de ondas, com um dado espectro de frequências, e uma população de grãos de poeira, com distribuição de tamanho observada, foi possível mostrar que o amortecimento é eficiente em uma larga banda de frequências. Neste caso as ondas seriam rapidamente amortecidas gerando pequenas condensações de alta densidade, e não poderiam ser utilizadas para explicar a estabilidade de uma nuvem inteira. Desta forma, rotação e turbulência seriam candidatos alternativos para garantir a estabilidade destes objetos.

Is There a Chance for a Standardised User Interface?

ERIC Educational Resources Information Center

Fletcher, Liz

1993-01-01

Issues concerning the implementation of standard user interfaces for CD-ROMs are discussed, including differing perceptions of the ideal interface, graphical user interfaces, user needs, and the standard protocols. It is suggested users should be able to select from a variety of user interfaces on each CD-ROM. (EA)

When the Interface Is a Face.

ERIC Educational Resources Information Center

Sproull, Lee; And Others

1996-01-01

Demonstrates that college students' responses to a talking-face computer interface differ from their responses to a text-display interface. In reaction to a humanlike interface, subjects attributed some personality traits to it, were more aroused by it, and tended to present themselves more positively. Gender differences in interface reactions…

Controllable Grid Interface Test System | Energy Systems Integration

Science.gov Websites

Facility | NREL Controllable Grid Interface Test System Controllable Grid Interface Test System NREL's controllable grid interface (CGI) test system can reduce certification testing time and costs grid interface is the first test facility in the United States that has fault simulation capabilities

Hierarchy of on-orbit servicing interfaces

NASA Technical Reports Server (NTRS)

Moe, Rud V.

1989-01-01

A series of equipment interfaces is involved in on-orbit servicing operations. The end-to-end hierarchy of servicing interfaces is presented. The interface concepts presented include structure and handling, and formats for transfer of resources (power, data, fluids, etc.). Consequences on cost, performance, and service ability of the use of standard designs or unique designs with interface adapters are discussed. Implications of the interface designs compatibility with remote servicing using telerobotic servicers are discussed.

HyFinBall: A Two-Handed, Hybrid 2D/3D Desktop VR Interface for Visualization

DTIC Science & Technology

2013-01-01

user study . This is done in the context of a rich, visual analytics interface containing coordinated views with 2D and 3D visualizations and...the user interface (hardware and software), the design space, as well as preliminary results of a formal user study . This is done in the context of a ... virtual reality , user interface , two-handed interface , hybrid user interface , multi-touch, gesture,

Method for determining optimal supercell representation of interfaces

NASA Astrophysics Data System (ADS)

Stradi, Daniele; Jelver, Line; Smidstrup, Søren; Stokbro, Kurt

2017-05-01

The geometry and structure of an interface ultimately determines the behavior of devices at the nanoscale. We present a generic method to determine the possible lattice matches between two arbitrary surfaces and to calculate the strain of the corresponding matched interface. We apply this method to explore two relevant classes of interfaces for which accurate structural measurements of the interface are available: (i) the interface between pentacene crystals and the (1 1 1) surface of gold, and (ii) the interface between the semiconductor indium-arsenide and aluminum. For both systems, we demonstrate that the presented method predicts interface geometries in good agreement with those measured experimentally, which present nontrivial matching characteristics and would be difficult to guess without relying on automated structure-searching methods.

Atomistic calculations of interface elastic properties in noncoherent metallic bilayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mi Changwen; Jun, Sukky; Kouris, Demitris A.

2008-02-15

The paper describes theoretical and computational studies associated with the interface elastic properties of noncoherent metallic bicrystals. Analytical forms of interface energy, interface stresses, and interface elastic constants are derived in terms of interatomic potential functions. Embedded-atom method potentials are then incorporated into the model to compute these excess thermodynamics variables, using energy minimization in a parallel computing environment. The proposed model is validated by calculating surface thermodynamic variables and comparing them with preexisting data. Next, the interface elastic properties of several fcc-fcc bicrystals are computed. The excess energies and stresses of interfaces are smaller than those on free surfacesmore » of the same crystal orientations. In addition, no negative values of interface stresses are observed. Current results can be applied to various heterogeneous materials where interfaces assume a prominent role in the systems' mechanical behavior.« less

Lattice structures and electronic properties of MO/MoSe2 interface from first-principles calculations

NASA Astrophysics Data System (ADS)

Zhang, Yu; Tang, Fu-Ling; Xue, Hong-Tao; Lu, Wen-Jiang; Liu, Jiang-Fei; Huang, Min

2015-02-01

Using first-principles plane-wave calculations within density functional theory, we theoretically studied the atomic structure, bonding energy and electronic properties of the perfect Mo (110)/MoSe2 (100) interface with a lattice mismatch less than 4.2%. Compared with the perfect structure, the interface is somewhat relaxed, and its atomic positions and bond lengths change slightly. The calculated interface bonding energy is about -1.2 J/m2, indicating that this interface is very stable. The MoSe2 layer on the interface has some interface states near the Fermi level, the interface states are mainly caused by Mo 4d orbitals, while the Se atom almost have no contribution. On the interface, Mo-5s and Se-4p orbitals hybridize at about -6.5 to -5.0 eV, and Mo-4d and Se-4p orbitals hybridize at about -5.0 to -1.0 eV. These hybridizations greatly improve the bonding ability of Mo and Se atom in the interface. By Bader charge analysis, we find electron redistribution near the interface which promotes the bonding of the Mo and MoSe2 layer.

Toward High-Performance Communications Interfaces for Science Problem Solving

NASA Astrophysics Data System (ADS)

Oviatt, Sharon L.; Cohen, Adrienne O.

2010-12-01

From a theoretical viewpoint, educational interfaces that facilitate communicative actions involving representations central to a domain can maximize students' effort associated with constructing new schemas. In addition, interfaces that minimize working memory demands due to the interface per se, for example by mimicking existing non-digital work practice, can preserve students' attentional focus on their learning task. In this research, we asked the question: What type of interface input capabilities provide best support for science problem solving in both low- and high- performing students? High school students' ability to solve a diverse range of biology problems was compared over longitudinal sessions while they used: (1) hardcopy paper and pencil (2) a digital paper and pen interface (3) pen tablet interface, and (4) graphical tablet interface. Post-test evaluations revealed that time to solve problems, meta-cognitive control, solution correctness, and memory all were significantly enhanced when using the digital pen and paper interface, compared with tablet interfaces. The tangible pen and paper interface also was the only alternative that significantly facilitated skill acquisition in low-performing students. Paradoxically, all students nonetheless believed that the tablet interfaces provided best support for their performance, revealing a lack of self-awareness about how to use computational tools to best advantage. Implications are discussed for how pen interfaces can be optimized for future educational purposes, and for establishing technology fluency curricula to improve students' awareness of the impact of digital tools on their performance.

Development of a User Interface for a Regression Analysis Software Tool

NASA Technical Reports Server (NTRS)

Ulbrich, Norbert Manfred; Volden, Thomas R.

2010-01-01

An easy-to -use user interface was implemented in a highly automated regression analysis tool. The user interface was developed from the start to run on computers that use the Windows, Macintosh, Linux, or UNIX operating system. Many user interface features were specifically designed such that a novice or inexperienced user can apply the regression analysis tool with confidence. Therefore, the user interface s design minimizes interactive input from the user. In addition, reasonable default combinations are assigned to those analysis settings that influence the outcome of the regression analysis. These default combinations will lead to a successful regression analysis result for most experimental data sets. The user interface comes in two versions. The text user interface version is used for the ongoing development of the regression analysis tool. The official release of the regression analysis tool, on the other hand, has a graphical user interface that is more efficient to use. This graphical user interface displays all input file names, output file names, and analysis settings for a specific software application mode on a single screen which makes it easier to generate reliable analysis results and to perform input parameter studies. An object-oriented approach was used for the development of the graphical user interface. This choice keeps future software maintenance costs to a reasonable limit. Examples of both the text user interface and graphical user interface are discussed in order to illustrate the user interface s overall design approach.

A Strategy Based on Protein-Protein Interface Motifs May Help in Identifying Drug Off-Targets

PubMed Central

Engin, H. Billur; Keskin, Ozlem; Nussinov, Ruth; Gursoy, Attila

2014-01-01

Networks are increasingly used to study the impact of drugs at the systems level. From the algorithmic standpoint, a drug can ‘attack’ nodes or edges of a protein-protein interaction network. In this work, we propose a new network strategy, “The Interface Attack”, based on protein-protein interfaces. Similar interface architectures can occur between unrelated proteins. Consequently, in principle, a drug that binds to one has a certain probability of binding others. The interface attack strategy simultaneously removes from the network all interactions that consist of similar interface motifs. This strategy is inspired by network pharmacology and allows inferring potential off-targets. We introduce a network model which we call “Protein Interface and Interaction Network (P2IN)”, which is the integration of protein-protein interface structures and protein interaction networks. This interface-based network organization clarifies which protein pairs have structurally similar interfaces, and which proteins may compete to bind the same surface region. We built the P2IN of p53 signaling network and performed network robustness analysis. We show that (1) ‘hitting’ frequent interfaces (a set of edges distributed around the network) might be as destructive as eleminating high degree proteins (hub nodes); (2) frequent interfaces are not always topologically critical elements in the network; and (3) interface attack may reveal functional changes in the system better than attack of single proteins. In the off-target detection case study, we found that drugs blocking the interface between CDK6 and CDKN2D may also affect the interaction between CDK4 and CDKN2D. PMID:22817115

Blind predictions of protein interfaces by docking calculations in CAPRI.

PubMed

Lensink, Marc F; Wodak, Shoshana J

2010-11-15

Reliable prediction of the amino acid residues involved in protein-protein interfaces can provide valuable insight into protein function, and inform mutagenesis studies, and drug design applications. A fast-growing number of methods are being proposed for predicting protein interfaces, using structural information, energetic criteria, or sequence conservation or by integrating multiple criteria and approaches. Overall however, their performance remains limited, especially when applied to nonobligate protein complexes, where the individual components are also stable on their own. Here, we evaluate interface predictions derived from protein-protein docking calculations. To this end we measure the overlap between the interfaces in models of protein complexes submitted by 76 participants in CAPRI (Critical Assessment of Predicted Interactions) and those of 46 observed interfaces in 20 CAPRI targets corresponding to nonobligate complexes. Our evaluation considers multiple models for each target interface, submitted by different participants, using a variety of docking methods. Although this results in a substantial variability in the prediction performance across participants and targets, clear trends emerge. Docking methods that perform best in our evaluation predict interfaces with average recall and precision levels of about 60%, for a small majority (60%) of the analyzed interfaces. These levels are significantly higher than those obtained for nonobligate complexes by most extant interface prediction methods. We find furthermore that a sizable fraction (24%) of the interfaces in models ranked as incorrect in the CAPRI assessment are actually correctly predicted (recall and precision ≥50%), and that these models contribute to 70% of the correct docking-based interface predictions overall. Our analysis proves that docking methods are much more successful in identifying interfaces than in predicting complexes, and suggests that these methods have an excellent potential of addressing the interface prediction challenge. © 2010 Wiley-Liss, Inc.

Selectivity and Longevity of Peripheral-Nerve and Machine Interfaces: A Review

PubMed Central

Ghafoor, Usman; Kim, Sohee; Hong, Keum-Shik

2017-01-01

For those individuals with upper-extremity amputation, a daily normal living activity is no longer possible or it requires additional effort and time. With the aim of restoring their sensory and motor functions, theoretical and technological investigations have been carried out in the field of neuroprosthetic systems. For transmission of sensory feedback, several interfacing modalities including indirect (non-invasive), direct-to-peripheral-nerve (invasive), and cortical stimulation have been applied. Peripheral nerve interfaces demonstrate an edge over the cortical interfaces due to the sensitivity in attaining cortical brain signals. The peripheral nerve interfaces are highly dependent on interface designs and are required to be biocompatible with the nerves to achieve prolonged stability and longevity. Another criterion is the selection of nerves that allows minimal invasiveness and damages as well as high selectivity for a large number of nerve fascicles. In this paper, we review the nerve-machine interface modalities noted above with more focus on peripheral nerve interfaces, which are responsible for provision of sensory feedback. The invasive interfaces for recording and stimulation of electro-neurographic signals include intra-fascicular, regenerative-type interfaces that provide multiple contact channels to a group of axons inside the nerve and the extra-neural-cuff-type interfaces that enable interaction with many axons around the periphery of the nerve. Section Current Prosthetic Technology summarizes the advancements made to date in the field of neuroprosthetics toward the achievement of a bidirectional nerve-machine interface with more focus on sensory feedback. In the Discussion section, the authors propose a hybrid interface technique for achieving better selectivity and long-term stability using the available nerve interfacing techniques. PMID:29163122

Role of air-water interfaces in colloid transport in porous media: A review

NASA Astrophysics Data System (ADS)

Flury, Markus; Aramrak, Surachet

2017-07-01

Air-water interfaces play an important role in unsaturated porous media, giving rise to phenomena like capillarity. Less recognized and understood are interactions of colloids with the air-water interface in porous media and the implications of these interactions for fate and transport of colloids. In this review, we discuss how colloids, both suspended in the aqueous phase and attached at pore walls, interact with air-water interfaces in porous media. We discuss the theory of colloid/air-water interface interactions, based on the different forces acting between colloids and the air-water interface (DLVO, hydrophobic, capillary forces) and based on thermodynamic considerations (Gibbs free energy). Subsurface colloids are usually electrostatically repelled from the air-water interface because most subsurface colloids and the air-water are negatively charged. However, hydrophobic interactions can lead to attraction to the air-water interface. When colloids are at the air-water interface, capillary forces are usually dominant over other forces. Moving air-water interfaces are effective in mobilizing and transporting colloids from surfaces. Thermodynamic considerations show that, for a colloid, the air-water interface is the favored state as compared with the suspension phase, except for hydrophilic colloids in the nanometer size range. Experimental evidence indicates that colloid mobilization in soils often occurs through macropores, although matrix transport is also prevalent in absence of macropores. Moving air-water interfaces, e.g., occurring during infiltration, imbibition, or drainage, have been shown to scour colloids from surfaces and translocate colloids. Colloids can also be pinned to surfaces by thin water films and capillary menisci at the air-water-solid interface line, causing colloid retention and immobilization. Air-water interfaces thus can both mobilize or immobilize colloids in porous media, depending on hydrodynamics and colloid and surface chemistry.

Effect of a surface tension gradient on the slip flow along a superhydrophobic air-water interface

NASA Astrophysics Data System (ADS)

Song, Dong; Song, Baowei; Hu, Haibao; Du, Xiaosong; Du, Peng; Choi, Chang-Hwan; Rothstein, Jonathan P.

2018-03-01

Superhydrophobic surfaces have been shown to produce significant drag reduction in both laminar and turbulent flows by introducing an apparent slip velocity along an air-water interface trapped within the surface roughness. In the experiments presented within this study, we demonstrate the existence of a surface tension gradient associated with the resultant Marangoni flow along an air-water interface that causes the slip velocity and slip length to be significantly reduced. In this study, the slip velocity along a millimeter-sized air-water interface was investigated experimentally. This large-scale air-water interface facilitated a detailed investigation of the interfacial velocity profiles as the flow rate, interfacial curvature, and interface geometry were varied. For the air-water interfaces supported above continuous grooves (concentric rings within a torsional shear flow) where no surface tension gradient exists, a slip velocity as high as 30% of the bulk velocity was observed. However, for the air-water interfaces supported above discontinuous grooves (rectangular channels in a Poiseuille flow), the presence of a surface tension gradient reduced the slip velocity and in some cases resulted in an interfacial velocity that was opposite to the main flow direction. The curvature of the air-water interface in the spanwise direction was found to dictate the details of the interfacial flow profile with reverse flow in the center of the interface for concave surfaces and along the outside of the interface for convex surfaces. The deflection of the air-water interface was also found to greatly affect the magnitude of the slip. Numerical simulations imposed with a relatively small surface tension gradient along the air-water interface were able to predict both the reduced slip velocity and back flow along the air-water interface.

Adsorption of naphthalene and ozone on atmospheric air/ice interfaces coated with surfactants: a molecular simulation study.

PubMed

Liyana-Arachchi, Thilanga P; Valsaraj, Kalliat T; Hung, Francisco R

2012-03-15

The adsorption of gas-phase naphthalene and ozone molecules onto air/ice interfaces coated with different surfactant species (1-octanol, 1-hexadecanol, or 1-octanal) was investigated using classical molecular dynamics (MD) simulations. Naphthalene and ozone exhibit a strong preference to be adsorbed at the surfactant-coated air/ice interfaces, as opposed to either being dissolved into the bulk of the quasi-liquid layer (QLL) or being incorporated into the ice crystals. The QLL becomes thinner when the air/ice interface is coated with surfactant molecules. The adsorption of both naphthalene and ozone onto surfactant-coated air/ice interfaces is enhanced when compared to bare air/ice interface. Both naphthalene and ozone tend to stay dissolved in the surfactant layer and close to the QLL, rather than adsorbing on top of the surfactant molecules and close to the air region of our systems. Surfactants prefer to orient at a tilted angle with respect to the air/ice interface; the angular distribution and the most preferred angle vary depending on the hydrophilic end group, the length of the hydrophobic tail, and the surfactant concentration at the air/ice interface. Naphthalene prefers to have a flat orientation on the surfactant coated air/ice interface, except at high concentrations of 1-hexadecanol at the air/ice interface; the angular distribution of naphthalene depends on the specific surfactant and its concentration at the air/ice interface. The dynamics of naphthalene molecules at the surfactant-coated air/ice interface slow down as compared to those observed at bare air/ice interfaces. The presence of surfactants does not seem to affect the self-association of naphthalene molecules at the air/ice interface, at least for the specific surfactants and the range of concentrations considered in this study.

Effect of two layouts on high technology AAC navigation and content location by people with aphasia.

PubMed

Wallace, Sarah E; Hux, Karen

2014-03-01

Navigating high-technology augmentative and alternative communication (AAC) devices with dynamic displays can be challenging for people with aphasia. The purpose of this study was to determine which of two AAC interfaces two people with aphasia could use most efficiently and accurately. The researchers used a BCB'C' alternating treatment design to provide device-use instruction to two people with severe aphasia regarding two personalised AAC interfaces that had different navigation layouts but identical content. One interface had static buttons for homepage and go-back features, and the other interface had static buttons in a navigation ring layout. Throughout treatment, the researchers monitored participants' mastery patterns regarding navigation efficiency and accuracy when locating target messages. Participants' accuracy and efficiency improved with both interfaces given intervention; however, the navigation ring layout appeared more transparent and better facilitated navigation than the homepage layout. People with aphasia can learn to navigate computerised devices; however, interface layout can substantially affect the efficiency and accuracy with which they locate messages. Given intervention incorporating errorless learning principles, people with chronic aphasia can learn to navigate across multiple device levels to locate target sentences. Both navigation ring and homepage interfaces may be used by people with aphasia. Some people with aphasia may be more consistent and efficient in finding target sentences using the navigation ring interface than the homepage interface. Additionally, the navigation ring interface may be more transparent and easier for people with aphasia to master--that is, they may require fewer intervention sessions to learn to navigate the navigation ring interface. Generalisation of learning may result from use of the navigation ring interface. Specifically, people with aphasia may improve navigation with the homepage interface as a result of instruction on the navigation interface, but not vice versa.

Graphical user interface simplifies infusion pump programming and enhances the ability to detect pump-related faults.

PubMed

Syroid, Noah; Liu, David; Albert, Robert; Agutter, James; Egan, Talmage D; Pace, Nathan L; Johnson, Ken B; Dowdle, Michael R; Pulsipher, Daniel; Westenskow, Dwayne R

2012-11-01

Drug administration errors are frequent and are often associated with the misuse of IV infusion pumps. One source of these errors may be the infusion pump's user interface. We used failure modes-and-effects analyses to identify programming errors and to guide the design of a new syringe pump user interface. We designed the new user interface to clearly show the pump's operating state simultaneously in more than 1 monitoring location. We evaluated anesthesia residents in laboratory and simulated environments on programming accuracy and error detection between the new user interface and the user interface of a commercially available infusion pump. With the new user interface, we observed the number of programming errors reduced by 81%, the number of keystrokes per task reduced from 9.2 ± 5.0 to 7.5 ± 5.5 (mean ± SD), the time required per task reduced from 18.1 ± 14.1 seconds to 10.9 ± 9.5 seconds and significantly less perceived workload. Residents detected 38 of 70 (54%) of the events with the new user interface and 37 of 70 (53%) with the existing user interface, despite no experience with the new user interface and extensive experience with the existing interface. The number of programming errors and workload were reduced partly because it took less time and fewer keystrokes to program the pump when using the new user interface. Despite minimal training, residents quickly identified preexisting infusion pump problems with the new user interface. Intuitive and easy-to-program infusion pump interfaces may reduce drug administration errors and infusion pump-related adverse events.

Building intuitive 3D interfaces for virtual reality systems

NASA Astrophysics Data System (ADS)

Vaidya, Vivek; Suryanarayanan, Srikanth; Seitel, Mathias; Mullick, Rakesh

2007-03-01

An exploration of techniques for developing intuitive, and efficient user interfaces for virtual reality systems. Work seeks to understand which paradigms from the better-understood world of 2D user interfaces remain viable within 3D environments. In order to establish this a new user interface was created that applied various understood principles of interface design. A user study was then performed where it was compared with an earlier interface for a series of medical visualization tasks.

Surface tension and long range corrections of cylindrical interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bourasseau, E.; Malfreyt, P.; Ghoufi, A., E-mail: aziz.ghoufi@univ-rennes1.fr

2015-12-21

The calculation of the surface tension of curved interfaces has been deeply investigated from molecular simulation during this last past decade. Recently, the thermodynamic Test-Area (TA) approach has been extended to the calculation of surface tension of curved interfaces. In the case of the cylindrical vapour-liquid interfaces of water and Lennard-Jones fluids, it was shown that the surface tension was independent of the curvature of the interface. In addition, the surface tension of the cylindrical interface is higher than that of the planar interface. Molecular simulations of cylindrical interfaces have been so far performed (i) by using a shifted potential,more » (ii) by means of large cutoff without periodic boundary conditions, or (iii) by ignoring the long range corrections to the surface tension due to the difficulty to estimate them. Indeed, unlike the planar interfaces there are no available operational expressions to consider the tail corrections to the surface tension of cylindrical interfaces. We propose here to develop the long range corrections of the surface tension for cylindrical interfaces by using the non-exponential TA (TA2) method. We also extend the formulation of the Mecke-Winkelmann corrections initially developed for planar surfaces to cylindrical interfaces. We complete this study by the calculation of the surface tension of cylindrical surfaces of liquid tin and copper using the embedded atom model potentials.« less

A continuously growing web-based interface structure databank

NASA Astrophysics Data System (ADS)

Erwin, N. A.; Wang, E. I.; Osysko, A.; Warner, D. H.

2012-07-01

The macroscopic properties of materials can be significantly influenced by the presence of microscopic interfaces. The complexity of these interfaces coupled with the vast configurational space in which they reside has been a long-standing obstacle to the advancement of true bottom-up material behavior predictions. In this vein, atomistic simulations have proven to be a valuable tool for investigating interface behavior. However, before atomistic simulations can be utilized to model interface behavior, meaningful interface atomic structures must be generated. The generation of structures has historically been carried out disjointly by individual research groups, and thus, has constituted an overlap in effort across the broad research community. To address this overlap and to lower the barrier for new researchers to explore interface modeling, we introduce a web-based interface structure databank (www.isdb.cee.cornell.edu) where users can search, download and share interface structures. The databank is intended to grow via two mechanisms: (1) interface structure donations from individual research groups and (2) an automated structure generation algorithm which continuously creates equilibrium interface structures. In this paper, we describe the databank, the automated interface generation algorithm, and compare a subset of the autonomously generated structures to structures currently available in the literature. To date, the automated generation algorithm has been directed toward aluminum grain boundary structures, which can be compared with experimentally measured population densities of aluminum polycrystals.

What we learn from eclipsing binaries in the ultraviolet

NASA Technical Reports Server (NTRS)

Guinan, Edward F.

1990-01-01

Recent results on stars and stellar physics from IUE (International Ultraviolet Explorer) observations of eclipsing binaries are discussed. Several case studies are presented, including V 444 Cyg, Aur stars, V 471 Tau and AR Lac. Topics include stellar winds and mass loss, stellar atmospheres, stellar dynamos, and surface activity. Studies of binary star dynamics and evolution are discussed. The progress made with IUE in understanding the complex dynamical and evolutionary processes taking place in W UMa-type binaries and Algol systems is highlighted. The initial results of intensive studies of the W UMa star VW Cep and three representative Algol-type binaries (in different stages of evolution) focused on gas flows and accretion, are included. The future prospects of eclipsing binary research are explored. Remaining problems are surveyed and the next challenges are presented. The roles that eclipsing binaries could play in studies of stellar evolution, cluster dynamics, galactic structure, mass luminosity relations for extra galactic systems, cosmology, and even possible detection of extra solar system planets using eclipsing binaries are discussed.

The first photometric investigation and orbital period variation analysis of the W UMa type binary IK Bootis

NASA Astrophysics Data System (ADS)

Kriwattanawong, Wichean; Sanguansak, Nuanwan; Maungkorn, Sakdawoot

2017-08-01

With new CCD observations of the W UMa type binary IK Boo, we present the first investigation of photometric parameters and orbital period change. The BVRc light curve fit shows that IK Boo is a W-type contact system with a mass ratio of q = 1.146 and a shallow contact with a fill-out factor of f = 2.22%. The orbital period decrease was found to be a rate of -3.28 × 10-7 d yr-1, corresponding to a mass transfer from the more massive to the less massive component with a rate of -2.83 × 10-6 M⊙ yr-1. The inner and outer critical Roche lobes will contract and cause the contact degree to increase. Therefore, IK Boo may evolve into a deeper contact system. Furthermore, a possible cyclic variation was found with a period of 9.74 yr, which could be explained by the light-travel time effect due to the existence of a third companion in the system.

ASCA X-ray spectra of the active single stars Beta Ceti and pi(1) Ursae Majoris

NASA Technical Reports Server (NTRS)

Drake, S. A.; Singh, K. P.; White, N. E.; Simon, Theodore

1994-01-01

We present X-ray spectra obtaiined by ASCA of two single, active stars, the G dwarf pi(1) UMa, and the G9/K0 giant Beta Cet. The spectra of both stars require the presence of at least two plasma components with different temperatures, 0.3-0.4 keV and approximately 0.7 keV, in order for acceptable fits to be obtained. The spectral resolving power and signal-to-noise ratio of the solid state imaging spectrometer (SIS) spectra allow us to formally constrain the coronal abundances of a number of elements. In Beta Cet, we find Mg to be overabundant, while other elements such as O, Ne, and N are underabundant, relative to the solar photospheric values. From the lower signal-to-noise ratio SIS spectrum of pi(1) UMa, we find evidence for underabundances of O, Ne, and Fe. These results are discussed in the context of the present understanding of elemental abundances in solar and stellar coronae.

Reconstruction of the accretion disk in six cataclysmic variable stars

NASA Astrophysics Data System (ADS)

Rutten, R. G. M.; van Paradijs, J.; Tinbergen, J.

1992-07-01

The maximum-entropy eclipse-mapping algorithm is used to reconstruct images of the accretion disks of the novalike variable stars RW Tri, UX UMa, SW Sex, LX Ser, V 1315 Aql, and V363 Aur. The 2D disk intensity maps deduced from the light curves reveal the size of the disk and its radial intensity dependence. Black-body temperature maps deduced from the intensity maps at different wavelengths show that the disks in RW Tri, UX UMa, and V363 Aur have a radial temperature dependence which closely matches the fundamental theoretical run of the effective temperature with radial distance from disk center: T(eff) varies as R exp -3/4. The system V1315 Aql and SW Sex exhibit a much flatter run of T(R) in the inner region of the disk, while LX Ser appears to hold a position in between these two extremes. The consequences of these results for accretion disk models are also discussed.

Trombose venosa profunda e vírus chicungunha

PubMed Central

Marques, Marcos Arêas; Adami de Sá, Fernanda Penza; Lupi, Otília; Brasil, Patricia; von Ristow, Arno

2017-01-01

Resumo Algumas infecções virais sistêmicas podem estar relacionadas ao desenvolvimento de trombose venosa profunda e/ou embolia pulmonar. Essa associação já está bem descrita em pacientes com infeções pelo vírus da imunodeficiência humana (HIV), hepatite C ou influenza. Recentemente introduzido no continente americano, o vírus chicungunha, agente etiológico da febre de chicungunha, ainda não tem essa relação bem sedimentada, mas com o aumento progressivo de sua incidência e pelo fato dessa infecção causar, muitas vezes, uma restrição severa da locomoção por poliartralgia e uma possível lesão endotelial direta, casos de tromboembolismo venoso podem começar a ser descritos. Neste relato de caso, descrevemos um paciente que desenvolveu trombose de veia poplítea direita durante internação para tratamento de febre por infecção por vírus chicungunha e poliartralgia severa. PMID:29930626

Populações estelares em galáxias HII

NASA Astrophysics Data System (ADS)

Westera, P.; Cuisinier, F.; Telles, E.; Kehrig, C.

2003-08-01

Analisamos o conteúdo estelar de 74 galáxias HII a partir do contínuo observado nos espectros ópticos dessas galáxias, utilizando métodos de síntese de população estelar. Descobrimos que todas as galáxias para as quais encontramos soluções contêm uma população estelar velha que domina a massa estelar, e numa maioria dessas também encontramos evidência de uma população de idade intermediaria além da geração jovem que está se formando agora. Concluímos que a formação estelar dessas galáxias se realiza em surtos individuais, Esses surtos são interrompidos por longos períodos de inatividade, com os primeiros consumindo a maior parte do gás. Sugerimos, portanto, que as galáxias HII sejam galáxias anãs normais flagradas em um período de surto.

Atomistic study on the FCC/BCC interface structure with {112}KS orientation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Keonwook; Beyerlein, Irene; Han, Weizhong

2011-09-23

In this study, atomistic simulation is used to explore the atomic interface structure, the intrinsic defect network, and mechanism of twin formation from the {112}KS Cu-Nb interface. The interface structure of different material systems AI-Fe and AI-Nb are also compared with Cu-Nb interface.

Radiation Tolerant Interfaces: Influence of Local Stoichiometry at the Misfit Dislocation on Radiation Damage Resistance of Metal/Oxide Interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shutthanandan, Vaithiyalingam; Choudhury, Samrat; Manandhar, Sandeep

To understand how variations in interface properties such as misfit-dislocation density and local chemistry affect radiation-induced defect absorption and recombination, we have explored a model system of CrxV1-x alloy epitaxial films deposited on MgO single crystals. By controlling film composition, the lattice mismatch with MgO was adjusted so that the misfit-dislocation density varies at the interface. These interfaces were exposed to irradiation and in situ results show that the film with a semi-coherent interface (Cr) withstands irradiation while V film, which has similar semi-coherent interface like Cr, showed the largest damage. Theoretical calculations indicate that, unlike at metal/metal interfaces, themore » misfit dislocation density does not dominate radiation damage tolerance at metal/oxide interfaces. Rather, the stoichiometry, and the precise location of the misfit-dislocation density relative to the interface, drives defect behavior. Together, these results demonstrate the sensitivity of defect recombination to interfacial chemistry and provide new avenues for engineering radiation-tolerant nanomaterials.« less

Interface Stability Influences Torso Muscle Recruitment and Spinal Load During Pushing Tasks

PubMed Central

LEE, P. J.; GRANATA, K. P.

2006-01-01

Handle or interface design can influence torso muscle recruitment and spinal load during pushing tasks. The objective of the study was to provide insight into the role of interface stability with regard to torso muscle recruitment and biomechanical loads on the spine. Fourteen subjects generated voluntary isometric trunk flexion force against a rigid interface and similar flexion exertions against an unstable interface, which simulated handle design in a cart pushing task. Normalized electromyographic (EMG) activity in the rectus abdominus, external oblique and internal oblique muscles increased with exertion effort. When using the unstable interface, EMG activity in the internal and external oblique muscle groups was greater than when using the rigid interface. Results agreed with trends from a biomechanical model implemented to predict the muscle activation necessary to generate isometric pushing forces and maintain spinal stability when using the two different interface designs. The co-contraction contributed to increased spinal load when using the unstable interface. It was concluded that handle or interface design and stability may influence spinal load and associated risk of musculoskeletal injury during manual materials tasks that involve pushing exertions. PMID:16540437

UIVerify: A Web-Based Tool for Verification and Automatic Generation of User Interfaces

NASA Technical Reports Server (NTRS)

Shiffman, Smadar; Degani, Asaf; Heymann, Michael

2004-01-01

In this poster, we describe a web-based tool for verification and automatic generation of user interfaces. The verification component of the tool accepts as input a model of a machine and a model of its interface, and checks that the interface is adequate (correct). The generation component of the tool accepts a model of a given machine and the user's task, and then generates a correct and succinct interface. This write-up will demonstrate the usefulness of the tool by verifying the correctness of a user interface to a flight-control system. The poster will include two more examples of using the tool: verification of the interface to an espresso machine, and automatic generation of a succinct interface to a large hypothetical machine.

An Overview of Recent Patents on Musculoskeletal Interface Tissue Engineering

PubMed Central

Rao, Rohit T.; Browe, Daniel P.; Lowe, Christopher J.; Freeman, Joseph W.

2018-01-01

Interface tissue engineering involves the development of engineered grafts that promote integration between multiple tissue types. Musculoskeletal tissue interfaces are critical to the safe and efficient transmission of mechanical forces between multiple musculoskeletal tissues e.g. between ligament and bone tissue. However, these interfaces often do not physiologically regenerate upon injury, resulting in impaired tissue function. Therefore, interface tissue engineering approaches are considered to be particularly relevant for the structural restoration of musculoskeletal tissues interfaces. In this article we provide an overview of the various strategies used for engineering musculoskeletal tissue interfaces with a specific focus on the recent important patents that have been issued for inventions that were specifically designed for engineering musculoskeletal interfaces as well as those that show promise to be adapted for this purpose. PMID:26577344

A Galerkin formulation of the MIB method for three dimensional elliptic interface problems

PubMed Central

Xia, Kelin; Wei, Guo-Wei

2014-01-01

We develop a three dimensional (3D) Galerkin formulation of the matched interface and boundary (MIB) method for solving elliptic partial differential equations (PDEs) with discontinuous coefficients, i.e., the elliptic interface problem. The present approach builds up two sets of elements respectively on two extended subdomains which both include the interface. As a result, two sets of elements overlap each other near the interface. Fictitious solutions are defined on the overlapping part of the elements, so that the differentiation operations of the original PDEs can be discretized as if there was no interface. The extra coefficients of polynomial basis functions, which furnish the overlapping elements and solve the fictitious solutions, are determined by interface jump conditions. Consequently, the interface jump conditions are rigorously enforced on the interface. The present method utilizes Cartesian meshes to avoid the mesh generation in conventional finite element methods (FEMs). We implement the proposed MIB Galerkin method with three different elements, namely, rectangular prism element, five-tetrahedron element and six-tetrahedron element, which tile the Cartesian mesh without introducing any new node. The accuracy, stability and robustness of the proposed 3D MIB Galerkin are extensively validated over three types of elliptic interface problems. In the first type, interfaces are analytically defined by level set functions. These interfaces are relatively simple but admit geometric singularities. In the second type, interfaces are defined by protein surfaces, which are truly arbitrarily complex. The last type of interfaces originates from multiprotein complexes, such as molecular motors. Near second order accuracy has been confirmed for all of these problems. To our knowledge, it is the first time for an FEM to show a near second order convergence in solving the Poisson equation with realistic protein surfaces. Additionally, the present work offers the first known near second order accurate method for C1 continuous or H2 continuous solutions associated with a Lipschitz continuous interface in a 3D setting. PMID:25309038

Biophysical Characterization of the Dimer and Tetramer Interface Interactions of the Human Cytosolic Malic Enzyme

PubMed Central

Murugan, Sujithkumar; Hung, Hui-Chih

2012-01-01

The cytosolic NADP+-dependent malic enzyme (c-NADP-ME) has a dimer-dimer quaternary structure in which the dimer interface associates more tightly than the tetramer interface. In this study, the urea-induced unfolding process of the c-NADP-ME interface mutants was monitored using fluorescence and circular dichroism spectroscopy, analytical ultracentrifugation and enzyme activities. Here, we demonstrate the differential protein stability between dimer and tetramer interface interactions of human c-NADP-ME. Our data clearly demonstrate that the protein stability of c-NADP-ME is affected predominantly by disruptions at the dimer interface rather than at the tetramer interface. First, during thermal stability experiments, the melting temperatures of the wild-type and tetramer interface mutants are 8–10°C higher than those of the dimer interface mutants. Second, during urea denaturation experiments, the thermodynamic parameters of the wild-type and tetramer interface mutants are almost identical. However, for the dimer interface mutants, the first transition of the urea unfolding curves shift towards a lower urea concentration, and the unfolding intermediate exist at a lower urea concentration. Third, for tetrameric WT c-NADP-ME, the enzyme is first dissociated from a tetramer to dimers before the 2 M urea treatment, and the dimers then dissociated into monomers before the 2.5 M urea treatment. With a dimeric tetramer interface mutant (H142A/D568A), the dimer completely dissociated into monomers after a 2.5 M urea treatment, while for a dimeric dimer interface mutant (H51A/D90A), the dimer completely dissociated into monomers after a 1.5 M urea treatment, indicating that the interactions of c-NADP-ME at the dimer interface are truly stronger than at the tetramer interface. Thus, this study provides a reasonable explanation for why malic enzymes need to assemble as a dimer of dimers. PMID:23284632

Kinetics of protein unfolding at interfaces

NASA Astrophysics Data System (ADS)

Yano, Yohko F.

2012-12-01

The conformation of protein molecules is determined by a balance of various forces, including van der Waals attraction, electrostatic interaction, hydrogen bonding, and conformational entropy. When protein molecules encounter an interface, they are often adsorbed on the interface. The conformation of an adsorbed protein molecule strongly depends on the interaction between the protein and the interface. Recent time-resolved investigations have revealed that protein conformation changes during the adsorption process due to the protein-protein interaction increasing with increasing interface coverage. External conditions also affect the protein conformation. This review considers recent dynamic observations of protein adsorption at various interfaces and their implications for the kinetics of protein unfolding at interfaces.

Scalable polylithic on-package integratable apparatus and method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khare, Surhud; Somasekhar, Dinesh; Borkar, Shekhar Y.

Described is an apparatus which comprises: a first die including: a processing core; a crossbar switch coupled to the processing core; and a first edge interface coupled to the crossbar switch; and a second die including: a first edge interface positioned at a periphery of the second die and coupled to the first edge interface of the first die, wherein the first edge interface of the first die and the first edge interface of the second die are positioned across each other; a clock synchronization circuit coupled to the second edge interface; and a memory interface coupled to the clockmore » synchronization circuit.« less

Reversible brazing process

DOEpatents

Pierce, Jim D.; Stephens, John J.; Walker, Charles A.

1999-01-01

A method of reversibly brazing surfaces together. An interface is affixed to each surface. The interfaces can be affixed by processes such as mechanical joining, welding, or brazing. The two interfaces are then brazed together using a brazing process that does not defeat the surface to interface joint. Interfaces of materials such as Ni-200 can be affixed to metallic surfaces by welding or by brazing with a first braze alloy. The Ni-200 interfaces can then be brazed together using a second braze alloy. The second braze alloy can be chosen so that it minimally alters the properties of the interfaces to allow multiple braze, heat and disassemble, rebraze cycles.

Insulator-semiconductor interface fixed charges in AlGaN/GaN metal-insulator-semiconductor devices with Al2O3 or AlTiO gate dielectrics

NASA Astrophysics Data System (ADS)

Le, Son Phuong; Nguyen, Duong Dai; Suzuki, Toshi-kazu

2018-01-01

We have investigated insulator-semiconductor interface fixed charges in AlGaN/GaN metal-insulator-semiconductor (MIS) devices with Al2O3 or AlTiO (an alloy of Al2O3 and TiO2) gate dielectrics obtained by atomic layer deposition on AlGaN. Analyzing insulator-thickness dependences of threshold voltages for the MIS devices, we evaluated positive interface fixed charges, whose density at the AlTiO/AlGaN interface is significantly lower than that at the Al2O3/AlGaN interface. This and a higher dielectric constant of AlTiO lead to rather shallower threshold voltages for the AlTiO gate dielectric than for Al2O3. The lower interface fixed charge density also leads to the fact that the two-dimensional electron concentration is a decreasing function of the insulator thickness for AlTiO, whereas being an increasing function for Al2O3. Moreover, we discuss the relationship between the interface fixed charges and interface states. From the conductance method, it is shown that the interface state densities are very similar at the Al2O3/AlGaN and AlTiO/AlGaN interfaces. Therefore, we consider that the lower AlTiO/AlGaN interface fixed charge density is not owing to electrons trapped at deep interface states compensating the positive fixed charges and can be attributed to a lower density of oxygen-related interface donors.

First-Principles Study on the Tensile Properties and Failure Mechanism of the CoSb3/Ti Interface

NASA Astrophysics Data System (ADS)

She, Wuchang; Liu, Qiwen; Mei, Hai; Zhai, Pengcheng; Li, Jun; Liu, Lisheng

2018-06-01

The mechanical properties of the CoSb3/Ti interface play a critical role in the application of thermoelectric devices. To understand the failure mechanism of the CoSb3(001)/Ti(01 \\bar{1} 0) interface, we investigated its response during tensile deformations by first-principles calculations. By comparison with the result between the perfect interface and the interface after atomic migration, we find that the atomic migration at the interface has an obvious influence on the mechanical properties. The tensile tests indicate the ideal tensile stress of the CoSb3/Ti interface after atomic migration decreases by about 8.1% as compared to that of the perfect one. The failure mechanism of the perfect CoSb3/Ti interface is different from that of the migrated CoSb3/Ti interface. For the perfect CoSb3/Ti interface, the breakage of the Co-Sb bond leads to the failure of the system. For the CoSb3/Ti interface after atomic migration, the breakage of the Sb-Sb bond leads to the failure of the system. This is mainly because the new ionic Ti-Sb bonds make the electrons redistributed and weaken the stiffness of the Co-Sb bonds.

Versatility and Invariance in the Evolution of Homologous Heteromeric Interfaces

PubMed Central

Andreani, Jessica; Faure, Guilhem; Guerois, Raphaël

2012-01-01

Evolutionary pressures act on protein complex interfaces so that they preserve their complementarity. Nonetheless, the elementary interactions which compose the interface are highly versatile throughout evolution. Understanding and characterizing interface plasticity across evolution is a fundamental issue which could provide new insights into protein-protein interaction prediction. Using a database of 1,024 couples of close and remote heteromeric structural interologs, we studied protein-protein interactions from a structural and evolutionary point of view. We systematically and quantitatively analyzed the conservation of different types of interface contacts. Our study highlights astonishing plasticity regarding polar contacts at complex interfaces. It also reveals that up to a quarter of the residues switch out of the interface when comparing two homologous complexes. Despite such versatility, we identify two important interface descriptors which correlate with an increased conservation in the evolution of interfaces: apolar patches and contacts surrounding anchor residues. These observations hold true even when restricting the dataset to transiently formed complexes. We show that a combination of six features related either to sequence or to geometric properties of interfaces can be used to rank positions likely to share similar contacts between two interologs. Altogether, our analysis provides important tracks for extracting meaningful information from multiple sequence alignments of conserved binding partners and for discriminating near-native interfaces using evolutionary information. PMID:22952442

Formal analysis and automatic generation of user interfaces: approach, methodology, and an algorithm.

PubMed

Heymann, Michael; Degani, Asaf

2007-04-01

We present a formal approach and methodology for the analysis and generation of user interfaces, with special emphasis on human-automation interaction. A conceptual approach for modeling, analyzing, and verifying the information content of user interfaces is discussed. The proposed methodology is based on two criteria: First, the interface must be correct--that is, given the interface indications and all related information (user manuals, training material, etc.), the user must be able to successfully perform the specified tasks. Second, the interface and related information must be succinct--that is, the amount of information (mode indications, mode buttons, parameter settings, etc.) presented to the user must be reduced (abstracted) to the minimum necessary. A step-by-step procedure for generating the information content of the interface that is both correct and succinct is presented and then explained and illustrated via two examples. Every user interface is an abstract description of the underlying system. The correspondence between the abstracted information presented to the user and the underlying behavior of a given machine can be analyzed and addressed formally. The procedure for generating the information content of user interfaces can be automated, and a software tool for its implementation has been developed. Potential application areas include adaptive interface systems and customized/personalized interfaces.

First-principles study of the structure properties of Al(111)/6H-SiC(0001) interfaces

NASA Astrophysics Data System (ADS)

Wu, Qingjie; Xie, Jingpei; Wang, Changqing; Li, Liben; Wang, Aiqin; Mao, Aixia

2018-04-01

This paper presents a systematic study on the energetic and electronic structure of the Al(111)/6H-SiC(0001) interfaces by using first-principles calculation with density functional theory (DFT). There are all three situations for no-vacuum layer of Al/SiC superlattics, and two cases of C-terminated and Si-terminated interfaces are compared and analyzed. Through the density of states analysis, the initial information of interface combination is obtained. Then the supercells are stretched vertically along the z-axis, and the fracture of the interface is obtained, and it is pointed out that C-terminated SiC and Al interfaces have a better binding property. And, the fracture positions of C-terminated and Si-terminated interfaces are different in the process of stretching. Then, the distance variation in the process of stretching, the charge density differences, and the distribution of the electrons near the interface are analyzed. Al these work makes the specific reasons for the interface fracture are obtained at last.

Understanding the Interface Dipole of Copper Phthalocyanine (CuPc)/C60: Theory and Experiment.

PubMed

Sai, Na; Gearba, Raluca; Dolocan, Andrei; Tritsch, John R; Chan, Wai-Lun; Chelikowsky, James R; Leung, Kevin; Zhu, Xiaoyang

2012-08-16

Interface dipole determines the electronic energy alignment in donor/acceptor interfaces and plays an important role in organic photovoltaics. Here we present a study combining first principles density functional theory (DFT) with ultraviolet photoemission spectroscopy (UPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to investigate the interface dipole, energy level alignment, and structural properties at the interface between CuPc and C60. DFT finds a sizable interface dipole for the face-on orientation, in quantitative agreement with the UPS measurement, and rules out charge transfer as the origin of the interface dipole. Using TOF-SIMS, we show that the interfacial morphology for the bilayer CuPc/C60 film is characterized by molecular intermixing, containing both the face-on and the edge-on orientation. The complementary experimental and theoretical results provide both insight into the origin of the interface dipole and direct evidence for the effect of interfacial morphology on the interface dipole.

The effect of visualizing the flow of multimedia content among and inside devices.

PubMed

Lee, Dong-Seok

2009-05-01

This study introduces a user interface, referred to as the flow interface, which provides a graphical representation of the movement of content among and inside audio/video devices. The proposed interface provides a different frame of reference with content-oriented visualization of the generation, manipulation, storage, and display of content as well as input and output. The flow interface was applied to a VCR/DVD recorder combo, one of the most complicated consumer products. A between-group experiment was performed to determine whether the flow interface helps users to perform various tasks and to examine the learning effect of the flow interface, particularly in regard to hooking up and recording tasks. The results showed that participants with access to the flow interface performed better in terms of success rate and elapsed time. In addition, the participants indicated that they could easily understand the flow interface. The potential of the flow interface for application to other audio video devices, and design issues requiring further consideration, are discussed.

Microgels at the Water/Oil Interface: In Situ Observation of Structural Aging and Two-Dimensional Magnetic Bead Microrheology.

PubMed

Huang, Shilin; Gawlitza, Kornelia; von Klitzing, Regine; Gilson, Laurent; Nowak, Johannes; Odenbach, Stefan; Steffen, Werner; Auernhammer, Günter K

2016-01-26

Stimuli-responsive microgels can be used as stabilizers for emulsions. However, the details of structure and the viscoelastic property of the microgel-laden interface are still not well-known. We synthesized fluorescently labeled microgels and used confocal microscopy to observe their arrangement at the water/oil interface. The microgels aggregated spontaneously at the interface, and the aggregated structure reorganized due to thermal motion. The structure of the interfacial layer formed by microgels depended on the microgel concentration at the interface. We suggest that the structure was controlled by the aggregation and adsorption of microgels at the interface. The interparticle separation between microgels at the interface decreased over time, implying a slow aging process of the microgels at the interface. Magnetic beads were introduced at the interface and used to trigger deformation of the microgel layer. Under compression and shear the microgels in the aggregated structure rearranged, leading to plastic deformation, and some elastic responses were also observed.

Parallel Fin ORU Thermal Interface for space applications. [Orbital Replaceable Unit

NASA Technical Reports Server (NTRS)

Stobb, C. A.; Limardo, Jose G.

1992-01-01

The Parallel Fin Thermal Interface has been developed as an Orbital Replaceable Unit (ORU) interface. The interface transfers heat from an ORU baseplate to a Heat Acquisition Plate (HAP) through pairs of fins sandwiched between insert plates that press against the fins with uniform pressure. The insert plates are spread apart for ORU baseplate separation and replacement. Two prototype interfaces with different fin dimensions were built (Model 140 and 380). Interfacing surface samples were found to have roughnesses of 56 to 89 nm. Conductance values of 267 to 420 W/sq m C were obtained for the 140 model in vacuum with interface pressures of 131 to 262 kPa (19 to 38 psi). Vacuum conductances ranging from 176 to 267 W/sq m F were obtained for the 380 model at interface pressures of 97 to 152 kPa (14 and 22 psi). Correlations from several sources were found to agree with test data within 20 percent using thermal math models of the interfaces.

Interface Shape Control Using Localized Heating during Bridgman Growth

NASA Technical Reports Server (NTRS)

Volz, M. P.; Mazuruk, K.; Aggarwal, M. D.; Croll, A.

2008-01-01

Numerical calculations were performed to assess the effect of localized radial heating on the melt-crystal interface shape during vertical Bridgman growth. System parameters examined include the ampoule, melt and crystal thermal conductivities, the magnitude and width of localized heating, and the latent heat of crystallization. Concave interface shapes, typical of semiconductor systems, could be flattened or made convex with localized heating. Although localized heating caused shallower thermal gradients ahead of the interface, the magnitude of the localized heating required for convexity was less than that which resulted in a thermal inversion ahead of the interface. A convex interface shape was most readily achieved with ampoules of lower thermal conductivity. Increasing melt convection tended to flatten the interface, but the amount of radial heating required to achieve a convex interface was essentially independent of the convection intensity.

Anomalous interface adhesion of graphene membranes

PubMed Central

He, Y.; Chen, W. F.; Yu, W. B.; Ouyang, G.; Yang, G. W.

2013-01-01

In order to understand the anomalous interface adhesion properties between graphene membranes and their substrates, we have developed a theoretical method to calibrate the interface adhesion energy of monolayer and multilayer graphene on substrates based on the bond relaxation consideration. Four kinds of interfaces, including graphene/SiO2, graphene/Cu, graphene/Cu/Ni and Cu/graphene/Ni, were taken into account. It was found that the membrane thickness and the interface confinement condition determine the adhesion energy. The relationship between the critical interface separation and the graphene thickness showed that the interface separation in the self-equilibrium state drops with decreasing membrane thickness. The size-dependent Young's modulus of graphene membrane and the interfacial condition were responsible for the novel interface adhesion energy. The proposed theory was expected to be applied to the design of graphene-based devices. PMID:24036502

Brain-computer interface training combined with transcranial direct current stimulation in patients with chronic severe hemiparesis: Proof of concept study.

PubMed

Kasashima-Shindo, Yuko; Fujiwara, Toshiyuki; Ushiba, Junichi; Matsushika, Yayoi; Kamatani, Daiki; Oto, Misa; Ono, Takashi; Nishimoto, Atsuko; Shindo, Keiichiro; Kawakami, Michiyuki; Tsuji, Tetsuya; Liu, Meigen

2015-04-01

Brain-computer interface technology has been applied to stroke patients to improve their motor function. Event-related desynchronization during motor imagery, which is used as a brain-computer interface trigger, is sometimes difficult to detect in stroke patients. Anodal transcranial direct current stimulation (tDCS) is known to increase event-related desynchronization. This study investigated the adjunctive effect of anodal tDCS for brain-computer interface training in patients with severe hemiparesis. Eighteen patients with chronic stroke. A non-randomized controlled study. Subjects were divided between a brain-computer interface group and a tDCS- brain-computer interface group and participated in a 10-day brain-computer interface training. Event-related desynchronization was detected in the affected hemisphere during motor imagery of the affected fingers. The tDCS-brain-computer interface group received anodal tDCS before brain-computer interface training. Event-related desynchronization was evaluated before and after the intervention. The Fugl-Meyer Assessment upper extremity motor score (FM-U) was assessed before, immediately after, and 3 months after, the intervention. Event-related desynchronization was significantly increased in the tDCS- brain-computer interface group. The FM-U was significantly increased in both groups. The FM-U improvement was maintained at 3 months in the tDCS-brain-computer interface group. Anodal tDCS can be a conditioning tool for brain-computer interface training in patients with severe hemiparetic stroke.

Studies on dispersive stabilization of porous media flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daripa, Prabir, E-mail: prabir.daripa@math.tamu.edu; Gin, Craig

Motivated by a need to improve the performance of chemical enhanced oil recovery (EOR) processes, we investigate dispersive effects on the linear stability of three-layer porous media flow models of EOR for two different types of interfaces: permeable and impermeable interfaces. Results presented are relevant for the design of smarter interfaces in the available parameter space of capillary number, Peclet number, longitudinal and transverse dispersion, and the viscous profile of the middle layer. The stabilization capacity of each of these two interfaces is explored numerically and conditions for complete dispersive stabilization are identified for each of these two types ofmore » interfaces. Key results obtained are (i) three-layer porous media flows with permeable interfaces can be almost completely stabilized by diffusion if the optimal viscous profile is chosen, (ii) flows with impermeable interfaces can also be almost completely stabilized for short time, but become more unstable at later times because diffusion flattens out the basic viscous profile, (iii) diffusion stabilizes short waves more than long waves which leads to a “turning point” Peclet number at which short and long waves have the same growth rate, and (iv) mechanical dispersion further stabilizes flows with permeable interfaces but in some cases has a destabilizing effect for flows with impermeable interfaces, which is a surprising result. These results are then used to give a comparison of the two types of interfaces. It is found that for most values of the flow parameters, permeable interfaces suppress flow instability more than impermeable interfaces.« less

Matched Interface and Boundary Method for Elasticity Interface Problems

PubMed Central

Wang, Bao; Xia, Kelin; Wei, Guo-Wei

2015-01-01

Elasticity theory is an important component of continuum mechanics and has had widely spread applications in science and engineering. Material interfaces are ubiquity in nature and man-made devices, and often give rise to discontinuous coefficients in the governing elasticity equations. In this work, the matched interface and boundary (MIB) method is developed to address elasticity interface problems. Linear elasticity theory for both isotropic homogeneous and inhomogeneous media is employed. In our approach, Lamé’s parameters can have jumps across the interface and are allowed to be position dependent in modeling isotropic inhomogeneous material. Both strong discontinuity, i.e., discontinuous solution, and weak discontinuity, namely, discontinuous derivatives of the solution, are considered in the present study. In the proposed method, fictitious values are utilized so that the standard central finite different schemes can be employed regardless of the interface. Interface jump conditions are enforced on the interface, which in turn, accurately determines fictitious values. We design new MIB schemes to account for complex interface geometries. In particular, the cross derivatives in the elasticity equations are difficult to handle for complex interface geometries. We propose secondary fictitious values and construct geometry based interpolation schemes to overcome this difficulty. Numerous analytical examples are used to validate the accuracy, convergence and robustness of the present MIB method for elasticity interface problems with both small and large curvatures, strong and weak discontinuities, and constant and variable coefficients. Numerical tests indicate second order accuracy in both L∞ and L2 norms. PMID:25914439

How interfaces affect hydrophobically driven polymer folding.

PubMed

Jamadagni, Sumanth N; Godawat, Rahul; Dordick, Jonathan S; Garde, Shekhar

2009-04-02

Studies of folding-unfolding of hydrophobic polymers in water provide an excellent starting point to probe manybody hydrophobic interactions in the context of realistic self-assembly processes. Such studies in bulk water have highlighted the similarities between thermodynamics of polymer collapse and of protein folding, and emphasized the role of hydration-water structure, density, and fluctuations-in the folding kinetics. Hydrophobic polymers are interfacially active-that is, they prefer locations at aqueous interfaces relative to bulk water-consistent with their low solubility. How does the presence of a hydrophobic solid surface or an essentially hydrophobic vapor-water interface affect the structural, thermodynamic, and kinetic aspects of polymer folding? Using extensive molecular dynamics simulations, we show that the large hydrophobic driving force for polymer collapse in bulk water is reduced at a solid alkane-water interface and further reduced at a vapor-water interface. As a result, at the solid-water interface, folded structures are marginally stable, whereas the vapor-liquid interface unfolds polymers completely. Structural sampling is also significantly affected by the interface. For example, at the solid-water interface, polymer conformations are quasi-2- dimensional, with folded states being pancake-like structures. At the vapor-water interface, the hydrophobic polymer is significantly excluded from the water phase and freely samples a broad range of compact to extended structures. Interestingly, although the driving force for folding is considerably lower, kinetics of folding are faster at both interfaces, highlighting the role of enhanced water fluctuations and dynamics at a hydrophobic interface.

An evaluation of unisensory and multisensory adaptive flight-path navigation displays

NASA Astrophysics Data System (ADS)

Moroney, Brian W.

1999-11-01

The present study assessed the use of unimodal (auditory or visual) and multimodal (audio-visual) adaptive interfaces to aid military pilots in the performance of a precision-navigation flight task when they were confronted with additional information-processing loads. A standard navigation interface was supplemented by adaptive interfaces consisting of either a head-up display based flight director, a 3D virtual audio interface, or a combination of the two. The adaptive interfaces provided information about how to return to the pathway when off course. Using an advanced flight simulator, pilots attempted two navigation scenarios: (A) maintain proper course under normal flight conditions and (B) return to course after their aircraft's position has been perturbed. Pilots flew in the presence or absence of an additional information-processing task presented in either the visual or auditory modality. The additional information-processing tasks were equated in terms of perceived mental workload as indexed by the NASA-TLX. Twelve experienced military pilots (11 men and 1 woman), naive to the purpose of the experiment, participated in the study. They were recruited from Wright-Patterson Air Force Base and had a mean of 2812 hrs. of flight experience. Four navigational interface configurations, the standard visual navigation interface alone (SV), SV plus adaptive visual, SV plus adaptive auditory, and SV plus adaptive visual-auditory composite were combined factorially with three concurrent tasks (CT), the no CT, the visual CT, and the auditory CT, a completely repeated measures design. The adaptive navigation displays were activated whenever the aircraft was more than 450 ft off course. In the normal flight scenario, the adaptive interfaces did not bolster navigation performance in comparison to the standard interface. It is conceivable that the pilots performed quite adequately using the familiar generic interface under normal flight conditions and hence showed no added benefit of the adaptive interfaces. In the return-to-course scenario, the relative advantages of the three adaptive interfaces were dependent upon the nature of the CT in a complex way. In the absence of a CT, recovery heading performance was superior with the adaptive visual and adaptive composite interfaces compared to the adaptive auditory interface. In the context of a visual CT, recovery when using the adaptive composite interface was superior to that when using the adaptive visual interface. Post-experimental inquiry indicated that when faced with a visual CT, the pilots used the auditory component of the multimodal guidance display to detect gross heading errors and the visual component to make more fine-grained heading adjustments. In the context of the auditory CT, navigation performance using the adaptive visual interface tended to be superior to that when using the adaptive auditory interface. Neither CT performance nor NASA-TLX workload level was influenced differentially by the interface configurations. Thus, the potential benefits associated with the proposed interfaces appear to be unaccompanied by negative side effects involving CT interference and workload. The adaptive interface configurations were altered without any direct input from the pilot. Thus, it was feared that pilots might reject the activation of interfaces independent of their control. However, pilots' debriefing comments about the efficacy of the adaptive interface approach were very positive. (Abstract shortened by UMI.)

Perfil dos Professores de Ciências Naturais do Recôncavo da Bahia - Alunos da Disciplina Terra e Universo no Curso de Ciências Naturais do Parfor

NASA Astrophysics Data System (ADS)

Lima, S. R.; Cerqueira Júnior, W.; Dutra, G.

2011-12-01

Este trabalho foi desenvolvido pelo projeto Astronomia no Recôncavo da Bahia, no Centro de Formação de Professores da Universidade Federal do Recôncavo da Bahia. Traçamos o perfil de um grupo de professores que lecionam conteúdos de Ciências Naturais no recôncavo, alunos do curso de Licenciatura em Ciências Naturais, oferecido dentro do Plano Nacional de Formação de Professores da Educação Básica. Nosso objetivo era avaliar se eles estão preparados para trabalhar conteúdos de Astronomia e identificar suas dificuldades. Os resultados serviram para orientar o professor da disciplina “Terra e Universo”, oferecida no segundo semestre de 2010. Durante a primeira aula da disciplina Terra e Universo, os alunos responderam a um questionário contendo questões abertas e fechadas, divididas em duas partes. A primeira procurando caracterizar profissionalmente os alunos enquanto professores da rede pública da região do Recôncavo Sul da Bahia e uma segunda parte procurando identificar conhecimentos básicos em Astronomia. Os resultados indicam uma predominância de professores do sexo feminino, com idade superior aos 40 anos, pardos e sem formação específica para o ensino de ciências. A maioria leciona há mais de 15 anos para turmas do 1º ao 5º ano, alguns lecionam para turmas de 6º ao 9º ano. Quase todos nunca participaram de um curso de formação continuada em Astronomia. Além disso, não estão habituados a ler revistas especializadas e nem livros com esta temática. Os que procuram ensinar temas voltados para a Astronomia têm, no livro didático, a maior fonte de informação sobre o assunto. As respostas também indicam uma deficiência em conteúdos básicos como a compreensão da esfericidade da Terra, noções de verticalidade e gravidade, incapacidade de identificar a Terra como um planeta, no Sistema Solar, em uma galáxia, no Universo. Estes resultados ressaltam a importância de disciplinas de Astronomia básica na formação dos professores da região.

CLINICAL SIGNS AND SYMPTOMS OF SEXUALLY TRANSMITTED INFECTIONS COMMUNICATED IN LIBRAS.

PubMed

França, Inacia Sátiro Xavier de; Magalhães, Isabella Medeiros de Oliveira; Sousa, Francisco Stélio de; Coura, Alexsandro Silva; Silva, Arthur Felipe Rodrigues; Baptista, Rosilene Santos

2016-01-01

To validate a video containing image representations of clinical signs and symptoms of sexually transmitted infections expressed in Libras. Methodology development study conducted in an audio communication school. Thirty-six deaf people were selected. A video containing image representations of clinical signs and symptoms of sexually transmitted infections expressed in Libras was produced. Semantic validation was performed by deaf students and content validation by three judges who are Libras experts. The validation results were subjected to the Content Validity Index, where an index score > 0.80/80% was considered as agreement among judges. Seven signs and symptoms related to sexually transmitted infections were validated and obtained satisfactory Content Validity Indexes, most of them with 100% representativeness and agreement. The validation process made the expressions of signs and symptoms related to sexually transmitted infections represented in Libras valid for establishing effective communication in the area of the study, turning it into a care tool that facilitates and standardizes communication with deaf people through Libras. Validar um vídeo contendo as representações imagéticas de sinais e sintomas clínicos de infecções sexualmente transmissíveis expressas em Libras. Estudo de desenvolvimento metodológico, realizado em uma escola de audiocomunicação. Selecionou-se uma amostra de 36 surdos. Elaborou-se um vídeo contendo a representação imagética de sinais e sintomas de infecções sexualmente transmissíveis expressos em Libras. A validação semântica foi realizada pelos surdos e a validação de conteúdo por três juízes experts em Libras. Os resultados da validação foram submetidos ao Índice de Validade de Conteúdo, considerando-se o escore do índice > 0,80/80% de concordância entre os juízes. Foram validados sete sinais e sintomas relacionados às infecções sexualmente transmissíveis que obtiveram Índices de Validade de Conteúdos satisfatórios e em sua maioria com 100% de representatividade e concordância. O processo de validação tornou válidas as expressões de sinais e sintomas relacionados às infecções sexualmente transmissíveis representadas em Libras para estabelecer, na região do estudo, uma comunicação eficiente, tornando-se uma ferramenta assistiva que permite facilidade e uniformidade na comunicação com os surdos por meio da Libras.

Easy-to-use interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blattner, M M; Blattner, D O; Tong, Y

1999-04-01

Easy-to-use interfaces are a class of interfaces that fall between public access interfaces and graphical user interfaces in usability and cognitive difficulty. We describe characteristics of easy-to-use interfaces by the properties of four dimensions: selection, navigation, direct manipulation, and contextual metaphors. Another constraint we introduced was to include as little text as possible, and what text we have will be in at least four languages. Formative evaluations were conducted to identify and isolate these characteristics. Our application is a visual interface for a home automation system intended for a diverse set of users. The design will be expanded to accommodatemore » the visually disabled in the near future.« less

Protein interactions in 3D: from interface evolution to drug discovery.

PubMed

Winter, Christof; Henschel, Andreas; Tuukkanen, Anne; Schroeder, Michael

2012-09-01

Over the past 10years, much research has been dedicated to the understanding of protein interactions. Large-scale experiments to elucidate the global structure of protein interaction networks have been complemented by detailed studies of protein interaction interfaces. Understanding the evolution of interfaces allows one to identify convergently evolved interfaces which are evolutionary unrelated but share a few key residues and hence have common binding partners. Understanding interaction interfaces and their evolution is an important basis for pharmaceutical applications in drug discovery. Here, we review the algorithms and databases on 3D protein interactions and discuss in detail applications in interface evolution, drug discovery, and interface prediction. Copyright © 2012 Elsevier Inc. All rights reserved.

Urine collection apparatus. [feminine hygiene

NASA Technical Reports Server (NTRS)

Michaud, R. B. (Inventor)

1981-01-01

A urine collection device for females comprises an interface body with an interface surface for engagement with the user's body. The interface body comprises a forward portion defining a urine-receiving bore which has an inlet in the interface surface adapted to be disposed in surrounding relation to the urethral opening of the user. The interface body also has a rear portion integrally adjoining the forward portion and a non-invasive vaginal seal on the interface surface for sealing the vagina of the user from communication with the urine-receiving bore. An absorbent pad is removably supported on the interface body and extends laterally therefrom. A garment for supporting the urine collection is also disclosed.

Combinatorial Nano-Bio Interfaces.

PubMed

Cai, Pingqiang; Zhang, Xiaoqian; Wang, Ming; Wu, Yun-Long; Chen, Xiaodong

2018-06-08

Nano-bio interfaces are emerging from the convergence of engineered nanomaterials and biological entities. Despite rapid growth, clinical translation of biomedical nanomaterials is heavily compromised by the lack of comprehensive understanding of biophysicochemical interactions at nano-bio interfaces. In the past decade, a few investigations have adopted a combinatorial approach toward decoding nano-bio interfaces. Combinatorial nano-bio interfaces comprise the design of nanocombinatorial libraries and high-throughput bioevaluation. In this Perspective, we address challenges in combinatorial nano-bio interfaces and call for multiparametric nanocombinatorics (composition, morphology, mechanics, surface chemistry), multiscale bioevaluation (biomolecules, organelles, cells, tissues/organs), and the recruitment of computational modeling and artificial intelligence. Leveraging combinatorial nano-bio interfaces will shed light on precision nanomedicine and its potential applications.

User's Manual for the Object User Interface (OUI): An Environmental Resource Modeling Framework

USGS Publications Warehouse

Markstrom, Steven L.; Koczot, Kathryn M.

2008-01-01

The Object User Interface is a computer application that provides a framework for coupling environmental-resource models and for managing associated temporal and spatial data. The Object User Interface is designed to be easily extensible to incorporate models and data interfaces defined by the user. Additionally, the Object User Interface is highly configurable through the use of a user-modifiable, text-based control file that is written in the eXtensible Markup Language. The Object User Interface user's manual provides (1) installation instructions, (2) an overview of the graphical user interface, (3) a description of the software tools, (4) a project example, and (5) specifications for user configuration and extension.

XPI: The Xanadu Parameter Interface

NASA Technical Reports Server (NTRS)

White, N.; Barrett, P.; Oneel, B.; Jacobs, P.

1992-01-01

XPI is a table driven parameter interface which greatly simplifies both command driven programs such as BROWSE and XIMAGE as well as stand alone single-task programs. It moves all of the syntax and semantic parsing of commands and parameters out of the users code into common code and externally defined tables. This allows the programmer to concentrate on writing the code unique to the application rather than reinventing the user interface and for external graphical interfaces to interface with no changes to the command driven program. XPI also includes a compatibility library which allows programs written using the IRAF host interface (Mandel and Roll) to use XPI in place of the IRAF host interface.

Optical mass memory system (AMM-13). AMM/DBMS interface control document

NASA Technical Reports Server (NTRS)

Bailey, G. A.

1980-01-01

The baseline for external interfaces of a 10 to the 13th power bit, optical archival mass memory system (AMM-13) is established. The types of interfaces addressed include data transfer; AMM-13, Data Base Management System, NASA End-to-End Data System computer interconnect; data/control input and output interfaces; test input data source; file management; and facilities interface.

Confined methane-water interfacial layers and thickness measurements using in situ Raman spectroscopy.

PubMed

Pinho, Bruno; Liu, Yukun; Rizkin, Benjamin; Hartman, Ryan L

2017-11-07

Gas-liquid interfaces broadly impact our planet, yet confined interfaces behave differently than unconfined ones. We report the role of tangential fluid motion in confined methane-water interfaces. The interfaces are created using microfluidics and investigated by in situ 1D, 2D and 3D Raman spectroscopy. The apparent CH 4 and H 2 O concentrations are reported for Reynolds numbers (Re), ranging from 0.17 to 8.55. Remarkably, the interfaces are comprised of distinct layers of thicknesses varying from 23 to 57 μm. We found that rarefaction, mixture, thin film, and shockwave layers together form the interfaces. The results indicate that the mixture layer thickness (δ) increases with Re (δ ∝ Re), and traditional transport theory for unconfined interfaces does not explain the confined interfaces. A comparison of our results with thin film theory of air-water interfaces (from mass transfer experiments in capillary microfluidics) supports that the hydrophobicity of CH 4 could decrease the strength of water-water interactions, resulting in larger interfacial thicknesses. Our findings help explain molecular transport in confined gas-liquid interfaces, which are common in a broad range of societal applications.

Improved usability of a multi-infusion setup using a centralized control interface: A task-based usability test

PubMed Central

Cnossen, Fokie; Dieperink, Willem; Bult, Wouter; de Smet, Anne Marie; Touw, Daan J.; Nijsten, Maarten W.

2017-01-01

The objective of this study was to assess the usability benefits of adding a bedside central control interface that controls all intravenous (IV) infusion pumps compared to the conventional individual control of multiple infusion pumps. Eighteen dedicated ICU nurses volunteered in a between-subjects task-based usability test. A newly developed central control interface was compared to conventional control of multiple infusion pumps in a simulated ICU setting. Task execution time, clicks, errors and questionnaire responses were evaluated. Overall the central control interface outperformed the conventional control in terms of fewer user actions (40±3 vs. 73±20 clicks, p<0.001) and fewer user errors (1±1 vs. 3±2 errors, p<0.05), with no difference in task execution times (421±108 vs. 406±119 seconds, not significant). Questionnaires indicated a significant preference for the central control interface. Despite being novice users of the central control interface, ICU nurses displayed improved performance with the central control interface compared to the conventional interface they were familiar with. We conclude that the new user interface has an overall better usability than the conventional interface. PMID:28800617

Orientation Control of Interfacial Magnetism at La 0.67Sr 0.33MnO 3/SrTiO 3 Interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Er-Jia; Charlton, Timothy; Ambaye, Haile

Understanding the magnetism at the interface between a ferromagnet and an insulator is essential because the commonly posited magnetic “dead” layer close to an interface can be problematic in magnetic tunnel junctions. Previously, degradation of the magnetic interface was attributed to charge discontinuity across the interface. In this paper, the interfacial magnetism was investigated using three identically prepared La 0.67Sr 0.33MnO 3 (LSMO) thin films grown on different oriented SrTiO 3 (STO) substrates by polarized neutron reflectometry. In all cases the magnetization at the LSMO/STO interface is larger than the film bulk. We show that the interfacial magnetization is largestmore » across the LSMO/STO interfaces with (001) and (111) orientations, which have the largest net charge discontinuities across the interfaces. In contrast, the magnetization of LSMO/STO across the (110) interface, the orientation with no net charge discontinuity, is the smallest of the three orientations. We show that a magnetically degraded interface is not intrinsic to LSMO/STO heterostructures. Finally, the approach to use different crystallographic orientations provides a means to investigate the influence of charge discontinuity on the interfacial magnetization.« less

Interface Mediated Nucleation and Growth of Dislocations in fcc-bcc nanocomposite

NASA Astrophysics Data System (ADS)

Zhang, Ruifeng; Wang, Jian; Beyerlein, Irene J.; Germann, Timothy C.

2011-03-01

Heterophase interfaces play a crucial role in determining material strength for nanostructured materials because they can block, store, nucleate, and remove dislocations, the essential defects that enable plastic deformation. Much recent theoretical and experimental effort has been conducted on nanostructured Cu-Nb multilayer composites that exhibited extraordinarily high strength, ductility, and resistance to radiation and mechanical loading. In decreasing layer thicknesses to the order of a few tens of nanometers or less, the deformation behavior of such composites is mainly controlled by the Cu/Nb interface. In this work, we focus on the cooperative mechanisms of dislocation nucleation and growth from Cu/Nb interfaces, and their interaction with interface. Two types of experimentally observed Cu/Nb incoherent interfaces are comparatively studied. We found that the preferred dislocation nucleation sites are closely related to atomic interface structure, which in turn, depend on the orientation relationship. The activation stress and energies for an isolated Shockley dislocation loop of different sizes from specific interface sites depend strongly on dislocation size, atomic interface pattern, and loading conditions. Such findings provide important insight into the mechanical response of a wide range of fcc/bcc metallic nanocomposites via atomic interface design.

Orientation Control of Interfacial Magnetism at La 0.67Sr 0.33MnO 3/SrTiO 3 Interfaces

DOE PAGES

Guo, Er-Jia; Charlton, Timothy; Ambaye, Haile; ...

2017-05-16

Understanding the magnetism at the interface between a ferromagnet and an insulator is essential because the commonly posited magnetic “dead” layer close to an interface can be problematic in magnetic tunnel junctions. Previously, degradation of the magnetic interface was attributed to charge discontinuity across the interface. In this paper, the interfacial magnetism was investigated using three identically prepared La 0.67Sr 0.33MnO 3 (LSMO) thin films grown on different oriented SrTiO 3 (STO) substrates by polarized neutron reflectometry. In all cases the magnetization at the LSMO/STO interface is larger than the film bulk. We show that the interfacial magnetization is largestmore » across the LSMO/STO interfaces with (001) and (111) orientations, which have the largest net charge discontinuities across the interfaces. In contrast, the magnetization of LSMO/STO across the (110) interface, the orientation with no net charge discontinuity, is the smallest of the three orientations. We show that a magnetically degraded interface is not intrinsic to LSMO/STO heterostructures. Finally, the approach to use different crystallographic orientations provides a means to investigate the influence of charge discontinuity on the interfacial magnetization.« less

Dynamics of solid nanoparticles near a liquid-liquid interface

NASA Astrophysics Data System (ADS)

Daher, Ali; Ammar, Amine; Hijazi, Abbas

2018-05-01

The liquid - liquid interface can be used as a suitable medium for generating some nanostructured films of metals, or inorganic materials such as semi conducting metals. This process can be controlled well if we study the dynamics of nanoparticles (NPs) at the liquid-liquid interface which is a new field of study, and is not understood well yet. The dynamics of NPs at liquid-liquid interfaces is investigated by solving the fluid-particle and particle-particle interactions. Our work is based on the Molecular Dynamics (MD) simulation in addition to Phase Field (PF) method. We modeled the liquid-liquid interface using the diffuse interface model, where the interface is considered to have a characteristic thickness. We have shown that the concentration gradient of one fluid in the other gives rise to a hydrodynamic force that drives the NPs to agglomerate at the interface. These obtained results may introduce new applications where certain interfaces can be considered to be suitable mediums for the synthesis of nanostructured materials. In addition, some liquid interfaces can play the role of effective filters for different species of biological NPs and solid state waste NPs, which will be very important in many industrial and biomedical domains.

Microstructure stability during creep deformation of hard-oriented polysynthetically twinned crystal of TiAl alloy

NASA Astrophysics Data System (ADS)

Kim, Hee Y.; Maruyama, K.

2003-10-01

The hard-orientated polysynthetically twinned (PST) crystal with the lamellar plates oriented parallel to the compression axis was deformed at 1150 K under the applied stress of 158 to 316 MPa. Microstructural changes were examined quantitatively for the PST crystal during creep deformation. In the as-grown PST crystal of the present study, proportions of α 2/ γ, true twin, pseudotwin, and 120 deg rotational fault interfaces were 12, 59, 12, and 17 pct, respectively. After creep deformation, lamellar coarsening by dissolution of α 2 lamellae and migration of γ/γ interfaces were observed. The acceleration of creep rate after the minimum strain rate in the creep curve was attributed to the lamellar coarsening and destruction of lamellar structure during the creep deformation. Thirty-two percent of α 2/ γ interfaces, 51 pct of true twin interfaces, 74 pct of pseudotwin interfaces, and 80 pct of 120 deg rotational faults disappeared after 4 pct creep strain at 1150 K. The α 2/ γ interface was more stable than γ/γ interfaces during the creep deformation. The pseudotwin interface and 120 deg rotational fault were less thermally stable than the true twin interface for γ/γ interfaces.

Investigating buried polymer interfaces using sum frequency generation vibrational spectroscopy

PubMed Central

Chen, Zhan

2010-01-01

This paper reviews recent progress in the studies of buried polymer interfaces using sum frequency generation (SFG) vibrational spectroscopy. Both buried solid/liquid and solid/solid interfaces involving polymeric materials are discussed. SFG studies of polymer/water interfaces show that different polymers exhibit varied surface restructuring behavior in water, indicating the importance of probing polymer/water interfaces in situ. SFG has also been applied to the investigation of interfaces between polymers and other liquids. It has been found that molecular interactions at such polymer/liquid interfaces dictate interfacial polymer structures. The molecular structures of silane molecules, which are widely used as adhesion promoters, have been investigated using SFG at buried polymer/silane and polymer/polymer interfaces, providing molecular-level understanding of polymer adhesion promotion. The molecular structures of polymer/solid interfaces have been examined using SFG with several different experimental geometries. These results have provided molecular-level information about polymer friction, adhesion, interfacial chemical reactions, interfacial electronic properties, and the structure of layer-by-layer deposited polymers. Such research has demonstrated that SFG is a powerful tool to probe buried interfaces involving polymeric materials, which are difficult to study by conventional surface sensitive analytical techniques. PMID:21113334

Improved usability of a multi-infusion setup using a centralized control interface: A task-based usability test.

PubMed

Doesburg, Frank; Cnossen, Fokie; Dieperink, Willem; Bult, Wouter; de Smet, Anne Marie; Touw, Daan J; Nijsten, Maarten W

2017-01-01

The objective of this study was to assess the usability benefits of adding a bedside central control interface that controls all intravenous (IV) infusion pumps compared to the conventional individual control of multiple infusion pumps. Eighteen dedicated ICU nurses volunteered in a between-subjects task-based usability test. A newly developed central control interface was compared to conventional control of multiple infusion pumps in a simulated ICU setting. Task execution time, clicks, errors and questionnaire responses were evaluated. Overall the central control interface outperformed the conventional control in terms of fewer user actions (40±3 vs. 73±20 clicks, p<0.001) and fewer user errors (1±1 vs. 3±2 errors, p<0.05), with no difference in task execution times (421±108 vs. 406±119 seconds, not significant). Questionnaires indicated a significant preference for the central control interface. Despite being novice users of the central control interface, ICU nurses displayed improved performance with the central control interface compared to the conventional interface they were familiar with. We conclude that the new user interface has an overall better usability than the conventional interface.

Interface segregation behavior in thermal aged austenitic precipitation strengthened stainless steel.

PubMed

Li, Hui; Song, Hui; Liu, Wenqing; Xia, Shuang; Zhou, Bangxin; Su, Cheng; Ding, Wenyan

2015-12-01

The segregation of various elements at grain boundaries, precipitate/matrix interfaces were analyzed using atom probe tomography in an austenitic precipitation strengthened stainless steel aged at 750 °C for different time. Segregation of P, B and C at all types of interfaces in all the specimens were observed. However, Si segregated at all types of interfaces only in the specimen aged for 16 h. Enrichment of Ti at grain boundaries was evident in the specimen aged for 16 h, while Ti did not segregate at other interfaces. Mo varied considerably among interface types, e.g. from segregated at grain boundaries in the specimens after all the aging time to never segregate at γ'/γ phase interfaces. Cr co-segregated with C at grain boundaries, although carbides still did not nucleate at grain boundaries yet. Despite segregation tendency variations in different interface types, the segregation tendency evolution variation of different elements depending aging time were analyzed among all types of interfaces. Based on the experimental results, the enrichment factors, Gibbs interface excess and segregation free energies of segregated elements were calculated and discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Shock Interaction with a Finite Thickness Two-Gas Interface

NASA Astrophysics Data System (ADS)

Labenski, John; Kim, Yong

2006-03-01

A dual-driver shock tube was used to investigate the growth rate of a finite thickness two-gas interface after shock forcing. One driver was used to create an argon-refrigerant interface as the contact surface behind a weak shock wave. The other driver, at the opposite end of the driven section, generates a stronger shock of Mach 1.1 to 1.3 to force the interface back in front of the detector station. Two schlieren systems record the density fluctuations while light scattering detectors record the density of the refrigerant as a function of position over the interface during both it's initial passage and return. A pair of digital cameras take stereo images of the interface, as mapped out by the tracer particles under illumination by a Q-switched ruby laser. The amount of time that the interface is allowed to travel up the driven section determines the interaction time as a control. Comparisons made between the schlieren signals, light scattering detector outputs, and the images quantify the fingered characteristics of the interface and its growth due to shock forcing. The results show that the interface has a distribution of thicknesses and that the interaction with a shock further broadens the interface.

Effect of planar dielectric interfaces on fluorescence emission and detection. Evanescent excitation with high-aperture collection.

PubMed Central

Burghardt, T P; Thompson, N L

1984-01-01

We consider the effect of planar dielectric interfaces (e.g., solid/liquid) on the fluorescence emission of nearby probes. First, we derive an integral expression for the electric field radiated by an oscillating electric dipole when it is close to a dielectric interface. The electric field depends on the refractive indices of the interface, the orientation of the dipole, the distance from the dipole to the interface, and the position of observation. We numerically calculate the electric field intensity for a dipole on an interface, as a function of observation position. These results are applicable to fluorescent molecules excited by the evanescent field of a totally internally reflected laser beam and thus very close to a solid/liquid interface. Next, we derive an integral expression for the electric field radiated when a second dielectric interface is also close to the fluorescent molecule. We numerically calculate this intensity as observed through the second interface. These results are useful when the fluorescence is collected by a high-aperture microscope objective. Finally, we define and calculate a "dichroic factor," which describes the efficiency of collection, in the two-interface system, of polarized fluorescence. The limit when the first interface is removed is applicable for any high-aperture collection of polarized or unpolarized fluorescence. The limit when the second interface is removed has application in the collection of fluorescence with any aperture from molecules close to a dielectric interface. The results of this paper are required for the interpretation of order parameter measurements on fluorescent probes in supported phospholipid monolayers (Thompson, N.L., H. M. McConnell, and T. P. Burghardt, 1984, Biophys. J., 46:739-747). PMID:6518253

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chao, B.P.

This report presents a historical perspective of the difficulties associated with user interface design and a review of interface design techniques. Included in the report is an application using rapid-interface-prototyping to the development of CAMP's user interface. 24 refs., 2 tabs.

Water at Interfaces.

PubMed

Björneholm, Olle; Hansen, Martin H; Hodgson, Andrew; Liu, Li-Min; Limmer, David T; Michaelides, Angelos; Pedevilla, Philipp; Rossmeisl, Jan; Shen, Huaze; Tocci, Gabriele; Tyrode, Eric; Walz, Marie-Madeleine; Werner, Josephina; Bluhm, Hendrik

2016-07-13

The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives many electrochemical reactions, and the liquid/vapor interface, which governs the uptake and release of trace gases by the oceans and cloud droplets. In this article we review some of the recent experimental and theoretical advances in our knowledge of the properties of aqueous interfaces and discuss open questions and gaps in our understanding.

Thermal transport across metal silicide-silicon interfaces: First-principles calculations and Green's function transport simulations

NASA Astrophysics Data System (ADS)

Sadasivam, Sridhar; Ye, Ning; Feser, Joseph P.; Charles, James; Miao, Kai; Kubis, Tillmann; Fisher, Timothy S.

2017-02-01

Heat transfer across metal-semiconductor interfaces involves multiple fundamental transport mechanisms such as elastic and inelastic phonon scattering, and electron-phonon coupling within the metal and across the interface. The relative contributions of these different transport mechanisms to the interface conductance remains unclear in the current literature. In this work, we use a combination of first-principles calculations under the density functional theory framework and heat transport simulations using the atomistic Green's function (AGF) method to quantitatively predict the contribution of the different scattering mechanisms to the thermal interface conductance of epitaxial CoSi2-Si interfaces. An important development in the present work is the direct computation of interfacial bonding from density functional perturbation theory (DFPT) and hence the avoidance of commonly used "mixing rules" to obtain the cross-interface force constants from bulk material force constants. Another important algorithmic development is the integration of the recursive Green's function (RGF) method with Büttiker probe scattering that enables computationally efficient simulations of inelastic phonon scattering and its contribution to the thermal interface conductance. First-principles calculations of electron-phonon coupling reveal that cross-interface energy transfer between metal electrons and atomic vibrations in the semiconductor is mediated by delocalized acoustic phonon modes that extend on both sides of the interface, and phonon modes that are localized inside the semiconductor region of the interface exhibit negligible coupling with electrons in the metal. We also provide a direct comparison between simulation predictions and experimental measurements of thermal interface conductance of epitaxial CoSi2-Si interfaces using the time-domain thermoreflectance technique. Importantly, the experimental results, performed across a wide temperature range, only agree well with predictions that include all transport processes: elastic and inelastic phonon scattering, electron-phonon coupling in the metal, and electron-phonon coupling across the interface.

Understanding Protein-Interface Interactions of a Fusion Protein at Silicone Oil-Water Interface Probed by Sum Frequency Generation Vibrational Spectroscopy.

PubMed

Li, Yaoxin; Pan, Duohai; Nashine, Vishal; Deshmukh, Smeet; Vig, Balvinder; Chen, Zhan

2018-02-01

Protein adsorbed at the silicone oil-water interface can undergo a conformational change that has the potential to induce protein aggregation on storage. Characterization of the protein structures at interface is therefore critical for understanding the protein-interface interactions. In this article, we have applied sum frequency generation (SFG) spectroscopy for studying the secondary structures of a fusion protein at interface and the surfactant effect on protein adsorption to silicone oil-water interface. SFG and chiral SFG spectra from adsorbed protein in the amide I region were analyzed. The presence of beta-sheet vibrational band at 1635 cm -1 implies the protein secondary structure was likely perturbed when protein adsorbed at silicone oil interface. The time-dependent SFG study showed a significant reduction in the SFG signal of preadsorbed protein when polysorbate 20 was introduced, suggesting surfactant has stronger interaction with the interface leading to desorption of protein from the interface. In the preadsorbed surfactant and a mixture of protein/polysorbate 20, SFG analysis confirmed that surfactant can dramatically prevent the protein adsorption to silicone oil surface. This study has demonstrated the potential of SFG for providing the detailed molecular level understanding of protein conformation at interface and assessing the influence of surfactant on protein adsorption behavior. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

A generalized strategy for building resident database interfaces

NASA Technical Reports Server (NTRS)

Moroh, Marsha; Wanderman, Ken

1990-01-01

A strategy for building resident interfaces to host heterogeneous distributed data base management systems is developed. The strategy is used to construct several interfaces. A set of guidelines is developed for users to construct their own interfaces.

Speech-generating devices: effectiveness of interface design-a comparative study of autism spectrum disorders.

PubMed

Chen, Chien-Hsu; Wang, Chuan-Po; Lee, I-Jui; Su, Chris Chun-Chin

2016-01-01

We analyzed the efficacy of the interface design of speech generating devices on three non-verbal adolescents with autism spectrum disorder (ASD), in hopes of improving their on-campus communication and cognitive disability. The intervention program was created based on their social and communication needs in school. Two operating interfaces were designed and compared: the Hierarchical Relating Menu and the Pie Abbreviation-Expansion Menu. The experiment used the ABCACB multiple-treatment reversal design. The test items included: (1) accuracy of operating identification; (2) interface operation in response to questions; (3) degree of independent completion. Each of these three items improved with both intervention interfaces. The children were able to operate the interfaces skillfully and respond to questions accurately, which evidenced the effectiveness of the interfaces. We conclude that both interfaces are efficacious enough to help nonverbal children with ASD at different levels.

Ultra-thin silicon oxide layers on crystalline silicon wafers: Comparison of advanced oxidation techniques with respect to chemically abrupt SiO2/Si interfaces with low defect densities

NASA Astrophysics Data System (ADS)

Stegemann, Bert; Gad, Karim M.; Balamou, Patrice; Sixtensson, Daniel; Vössing, Daniel; Kasemann, Martin; Angermann, Heike

2017-02-01

Six advanced oxidation techniques were analyzed, evaluated and compared with respect to the preparation of high-quality ultra-thin oxide layers on crystalline silicon. The resulting electronic and chemical SiO2/Si interface properties were determined by a combined x-ray photoemission (XPS) and surface photovoltage (SPV) investigation. Depending on the oxidation technique, chemically abrupt SiO2/Si interfaces with low densities of interface states were fabricated on c-Si either at low temperatures, at short times, or in wet-chemical environment, resulting in each case in excellent interface passivation. Moreover, the beneficial effect of a subsequent forming gas annealing (FGA) step for the passivation of the SiO2/Si interface of ultra-thin oxide layers has been proven. Chemically abrupt SiO2/Si interfaces have been shown to generate less interface defect states.

On Abstractions and Simplifications in the Design of Human-Automation Interfaces

NASA Technical Reports Server (NTRS)

Heymann, Michael; Degani, Asaf; Shafto, Michael; Meyer, George; Clancy, Daniel (Technical Monitor)

2001-01-01

This report addresses the design of human-automation interaction from a formal perspective that focuses on the information content of the interface, rather than the design of the graphical user interface. It also addresses the, issue of the information provided to the user (e.g., user-manuals, training material, and all other resources). In this report, we propose a formal procedure for generating interfaces and user-manuals. The procedure is guided by two criteria: First, the interface must be correct, i.e., that with the given interface the user will be able to perform the specified tasks correctly. Second, the interface should be as succinct as possible. The report discusses the underlying concepts and the formal methods for this approach. Several examples are used to illustrate the procedure. The algorithm for constructing interfaces can be automated, and a preliminary software system for its implementation has been developed.

Comparing Text-based and Graphic User Interfaces for Novice and Expert Users

PubMed Central

Chen, Jung-Wei; Zhang, Jiajie

2007-01-01

Graphic User Interface (GUI) is commonly considered to be superior to Text-based User Interface (TUI). This study compares GUI and TUI in an electronic dental record system. Several usability analysis techniques compared the relative effectiveness of a GUI and a TUI. Expert users and novice users were evaluated in time required and steps needed to complete the task. A within-subject design was used to evaluate if the experience with either interface will affect task performance. The results show that the GUI interface was not better than the TUI for expert users. GUI interface was better for novice users. For novice users there was a learning transfer effect from TUI to GUI. This means a user interface is user-friendly or not depending on the mapping between the user interface and tasks. GUI by itself may or may not be better than TUI. PMID:18693811

Control of interface shape during high melting sesquioxide crystal growth by HEM technique

NASA Astrophysics Data System (ADS)

Hu, Kaiwei; Zheng, Lili; Zhang, Hui

2018-02-01

During crystal growth in heat exchanger method (HEM) system, the shape of the growth interface changes with the proceeding of the growth process, which limits the crystal size and reduces the quality of the crystal. In this paper, a modified HEM system is proposed to control the interface shape for growth of sesquioxide crystals. Numerical simulation is performed to predict heat transfer, melt flow and interface shape during growth of high melting sesquioxide crystals by the heat exchanger method. The results show that a flat or slightly convex interface shape is beneficial to reduce the solute pileup in front of the melt/crystal interface and decrease the radial temperature gradient inside the crystal during growth of sesquioxide crystals. The interface shape can be controlled by adjusting the gap size d and lower resistance heater power during growth. The growth rate and the melt/crystal interface position can be obtained by two measured temperatures.

Deformation of a free interface pierced by a tilted cylinder

NASA Astrophysics Data System (ADS)

Raufaste, C.; Kirstetter, G.; Celestini, F.; Cox, S. J.

2012-07-01

We investigate the interaction between an infinite cylinder and a free fluid-fluid interface governed only by its surface tension. We study the deformation of an initially flat interface when it is deformed by the presence of a cylindrical object, tilted at an arbitrary angle, that the interface “totally wets”. Our simulations predict all significant quantities such as the interface shape, the position of the contact line, and the force exerted by the interface on the cylinder. These results are compared with an experimental study of the penetration of a soap film by a cylindrical liquid jet. This dynamic situation exhibits all the characteristics of a totally wetting interface. We show that whatever the inclination, the force is always perpendicular to the plane of the interface, and its amplitude diverges as the inclination angle increases. Such results should bring new insights in both fluid and solid mechanics, from animal locomotion to surface micro-processing.

Biomimetic approaches with smart interfaces for bone regeneration.

PubMed

Sailaja, G S; Ramesh, P; Vellappally, Sajith; Anil, Sukumaran; Varma, H K

2016-11-05

A 'smart tissue interface' is a host tissue-biomaterial interface capable of triggering favourable biochemical events inspired by stimuli responsive mechanisms. In other words, biomaterial surface is instrumental in dictating the interface functionality. This review aims to investigate the fundamental and favourable requirements of a 'smart tissue interface' that can positively influence the degree of healing and promote bone tissue regeneration. A biomaterial surface when interacts synergistically with the dynamic extracellular matrix, the healing process become accelerated through development of a smart interface. The interface functionality relies equally on bound functional groups and conjugated molecules belonging to the biomaterial and the biological milieu it interacts with. The essential conditions for such a special biomimetic environment are discussed. We highlight the impending prospects of smart interfaces and trying to relate the design approaches as well as critical factors that determine species-specific functionality with special reference to bone tissue regeneration.

Cauchy integral method for two-dimensional solidification interface shapes

NASA Astrophysics Data System (ADS)

Siegel, R.; Sosoka, D. J.

1982-07-01

A method is developed to determine the shape of steady state solidification interfaces formed when liquid above its freezing point circulates over a cold surface. The solidification interface, which is at uniform temperature, will form in a shape such that the non-uniform energy convected to it is locally balanced by conduction into the solid. The interface shape is of interest relative to the crystal structure formed during solidification; regulating the crystal structure has application in casting naturally strengthened metallic composites. The results also pertain to phase-change energy storage devices, where the solidified configuration and overall heat transfer are needed. The analysis uses a conformal mapping technique to relate the desired interface coordinates to the components of the temperature gradient at the interface. These components are unknown because the interface shape is unknown. A Cauchy integral formulation provides a second relation involving the components, and a simultaneous solution yields the interface shape.

Ultrafast modification of the polarity at LaAlO3/SrTiO3 interfaces

NASA Astrophysics Data System (ADS)

Rubano, A.; Günter, T.; Fiebig, M.; Granozio, F. Miletto; Marrucci, L.; Paparo, D.

2018-01-01

Oxide growth with semiconductorlike accuracy has led to atomically precise thin films and interfaces that exhibit a plethora of phases and functionalities not found in the oxide bulk material. This has yielded spectacular discoveries such as the conducting, magnetic, and even superconducting LaAlO3/SrTiO3 interfaces separating two prototypical insulating perovskite materials. All these investigations, however, consider the static state at the interface, although studies on fast oxide interface dynamics would introduce a powerful degree of freedom to understanding the nature of the LaAlO3/SrTiO3 interface state. Here, we show that the polarization state at the LaAlO3/SrTiO3 interface can be optically enhanced or attenuated within picoseconds. Our observations are explained by a model based on charge propagation effects in the interfacial vicinity and transient polarization buildup at the interface.

On Abstractions and Simplifications in the Design of Human-Automation Interfaces

NASA Technical Reports Server (NTRS)

Heymann, Michael; Degani, Asaf; Clancy, Daniel (Technical Monitor)

2002-01-01

This report addresses the design of human-automation interaction from a formal perspective that focuses on the information content of the interface, rather than the design of the graphical user interface. It also addresses the issue of the information provided to the user (e.g., user-manuals, training material, and all other resources). In this report, we propose a formal procedure for generating interfaces and user-manuals. The procedure is guided by two criteria: First, the interface must be correct, that is, with the given interface the user will be able to perform the specified tasks correctly. Second, the interface should be succinct. The report discusses the underlying concepts and the formal methods for this approach. Two examples are used to illustrate the procedure. The algorithm for constructing interfaces can be automated, and a preliminary software system for its implementation has been developed.

Comparing Text-based and Graphic User Interfaces for novice and expert users.

PubMed

Chen, Jung-Wei; Zhang, Jiajie

2007-10-11

Graphic User Interface (GUI) is commonly considered to be superior to Text-based User Interface (TUI). This study compares GUI and TUI in an electronic dental record system. Several usability analysis techniques compared the relative effectiveness of a GUI and a TUI. Expert users and novice users were evaluated in time required and steps needed to complete the task. A within-subject design was used to evaluate if the experience with either interface will affect task performance. The results show that the GUI interface was not better than the TUI for expert users. GUI interface was better for novice users. For novice users there was a learning transfer effect from TUI to GUI. This means a user interface is user-friendly or not depending on the mapping between the user interface and tasks. GUI by itself may or may not be better than TUI.

Spacelab payload accommodation handbook. Appendix B: Structure interface definition module

NASA Technical Reports Server (NTRS)

1978-01-01

The mechanical interfaces between Spacelab and its payload are defined. The envelopes available for mounting payload hardware are specified together with the standard structural attachment interfaces. Overall load capabilities and the local load capabilities for individual attachment interfaces are defined for the standard mounting locations. The mechanical environment is defined and the mechanical interfaces between the payload and the EPDS, CDMS and ECS are included.

Are Bibliographic Management Software Search Interfaces Reliable?: A Comparison between Search Results Obtained Using Database Interfaces and the EndNote Online Search Function

ERIC Educational Resources Information Center

Fitzgibbons, Megan; Meert, Deborah

2010-01-01

The use of bibliographic management software and its internal search interfaces is now pervasive among researchers. This study compares the results between searches conducted in academic databases' search interfaces versus the EndNote search interface. The results show mixed search reliability, depending on the database and type of search…

TRU waste lead organization -- WIPP Project Office Interface Management semi-annual report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerrero, J.V.; Gorton, J.M.

1985-05-01

The Charter establishing the Interface Control Board and the administrative organization to manage the interface of the TRU Waste Lead Organization and the WIPP Project Office also requires preparation of a summary report describing significant interface activities.'' This report includes a discussion of Interface Working Group (IWG) recommendations and resolutions considered and implemented'' over the reporting period October 1984 to March 1985.

Interface structure in Cu/Ta2O5/Pt resistance switch: a first-principles study.

PubMed

Xiao, Bo; Watanabe, Satoshi

2015-01-14

The interface structures of a Cu/Ta2O5/Pt resistance switch under various oxidation conditions have been examined from first-principles. The O-rich Cu/Ta2O5 interface is found to be stable within a wide range of O chemical potentials. In this interface structure, a considerable number of interface Cu atoms tend to migrate to the amorphous Ta2O5 (a-Ta2O5) layer, which causes the formation of the Cu2O layer. The interface Cu atoms become more ionized with an increase in the interface O concentration and/or temperature. These ionized Cu(+) ions could function as one of the main sources for the formation of conduction filaments in the Cu/a-Ta2O5/Pt resistance switch. In contrast, the ionization of the interface Cu atoms is not observed in the Cu/crystal-Ta2O5 interface primarily due to the much lower Cu ionic conductivity in crystal-Ta2O5 than that in amorphous state. In addition, the Pt electrode could not be ionized, irrespective of the interface O concentration and temperature. The formation of interface O vacancies in Pt/Ta2O5 is always energetically more stable than that in Cu/Ta2O5, which may be partly responsible for the cone shape of conduction filament formed in the Cu/a-Ta2O5/Pt resistance switch, where the base of the cone lies on the Pt/Ta2O5 interface.

Change of the isoelectric point of hemoglobin at the air/water interface probed by the orientational flip-flop of water molecules.

PubMed

Devineau, Stéphanie; Inoue, Ken-Ichi; Kusaka, Ryoji; Urashima, Shu-Hei; Nihonyanagi, Satoshi; Baigl, Damien; Tsuneshige, Antonio; Tahara, Tahei

2017-04-19

Elucidation of the molecular mechanisms of protein adsorption is of essential importance for further development of biotechnology. Here, we use interface-selective nonlinear vibrational spectroscopy to investigate protein charge at the air/water interface by probing the orientation of interfacial water molecules. We measured the Im χ (2) spectra of hemoglobin, myoglobin, serum albumin and lysozyme at the air/water interface in the CH and OH stretching regions using heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy, and we deduced the isoelectric point of the protein by monitoring the orientational flip-flop of water molecules at the interface. Strikingly, our measurements indicate that the isoelectric point of hemoglobin is significantly lowered (by about one pH unit) at the air/water interface compared to that in the bulk. This can be predominantly attributed to the modifications of the protein structure at the air/water interface. Our results also suggest that a similar mechanism accounts for the modification of myoglobin charge at the air/water interface. This effect has not been reported for other model proteins at interfaces probed by conventional VSFG techniques, and it emphasizes the importance of the structural modifications of proteins at the interface, which can drastically affect their charge profiles in a protein-specific manner. The direct experimental approach using HD-VSFG can unveil the changes of the isoelectric point of adsorbed proteins at various interfaces, which is of major relevance to many biological applications and sheds new light on the effect of interfaces on protein charge.

Recent work on material interface reconstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mosso, S.J.; Swartz, B.K.

1997-12-31

For the last 15 years, many Eulerian codes have relied on a series of piecewise linear interface reconstruction algorithms developed by David Youngs. In a typical Youngs` method, the material interfaces were reconstructed based upon nearly cell values of volume fractions of each material. The interfaces were locally represented by linear segments in two dimensions and by pieces of planes in three dimensions. The first step in such reconstruction was to locally approximate an interface normal. In Youngs` 3D method, a local gradient of a cell-volume-fraction function was estimated and taken to be the local interface normal. A linear interfacemore » was moved perpendicular to the now known normal until the mass behind it matched the material volume fraction for the cell in question. But for distorted or nonorthogonal meshes, the gradient normal estimate didn`t accurately match that of linear material interfaces. Moreover, curved material interfaces were also poorly represented. The authors will present some recent work in the computation of more accurate interface normals, without necessarily increasing stencil size. Their estimate of the normal is made using an iterative process that, given mass fractions for nearby cells of known but arbitrary variable density, converges in 3 or 4 passes in practice (and quadratically--like Newton`s method--in principle). The method reproduces a linear interface in both orthogonal and nonorthogonal meshes. The local linear approximation is generally 2nd-order accurate, with a 1st-order accurate normal for curved interfaces in both two and three dimensional polyhedral meshes. Recent work demonstrating the interface reconstruction for curved surfaces will /be discussed.« less

Reduced interface spin polarization by antiferromagnetically coupled Mn segregated to the C o2MnSi /GaAs (001) interface

NASA Astrophysics Data System (ADS)

Rath, Ashutosh; Sivakumar, Chockalingam; Sun, C.; Patel, Sahil J.; Jeong, Jong Seok; Feng, J.; Stecklein, G.; Crowell, Paul A.; Palmstrøm, Chris J.; Butler, William H.; Voyles, Paul M.

2018-01-01

We have investigated the interfacial structure and its correlation with the calculated spin polarization in C o2MnSi /GaAs(001) lateral spin valves. C o2MnSi (CMS) films were grown on As-terminated c(4 ×4 ) GaAs(100) by molecular beam epitaxy using different first atomic layers: MnSi, Co, and Mn. Atomically resolved Z -contrast scanning transmission electron microscopy (STEM) imaging and electron energy loss spectroscopy (EELS) were used to develop atomic structural models of the CMS/GaAs interfaces that were used as inputs for first-principles calculations to understand the magnetic and electronic properties of the interface. First-principles structures were relaxed and then validated by comparing experimental and simulated high-resolution STEM images. STEM-EELS results show that all three films have similar six atomic layer thick, Mn- and As-rich multilayer interfaces. However, the Co-initiated interface contains a M n2As -like layer, which is antiferromagnetic, and which is not present in the other two interfaces. Density functional theory calculations show a higher degree of interface spin polarization in the Mn- and MnSi-initiated cases, compared to the Co-initiated case, although none of the interfaces are half-metallic. The loss of half-metallicity is attributed, at least in part, to the segregation of Mn at the interface, which leads to the formation of interface states. The implications for the performance of lateral spin valves based on these interfaces are discussed briefly.

Slippage on a particle-laden liquid-gas interface in textured microchannels

NASA Astrophysics Data System (ADS)

Gaddam, Anvesh; Agrawal, Amit; Joshi, Suhas S.; Thompson, Mark C.

2018-03-01

Despite numerous investigations in the literature on slip flows in textured microchannels, experimental results were seldom in agreement with the theory. It is conjectured that contamination of the liquid-gas interface by impurities might be one of the sources of this discrepancy. However, the effect of impurities on slippage at the liquid-gas interface is neither understood nor previously reported. To this end, this work presents numerical investigation on the flow past a liquid-gas interface embedded with solid particles in textured microchannels. Initially, we present numerical simulations past transverse ribs with cylindrical particles on the liquid-gas interface. A reduction in effective slip length (or slip loss) with respect to the particle-free interface as a function of gas fraction, constriction ratio, and particle position was quantified. A significant slip loss (˜20-80%) was induced, owing to acceleration-deceleration cycles experienced by the liquid advecting across the particle-laden liquid-gas interface. Even a small number of solid particles adsorbed on a liquid-gas interface were shown to reduce the effective slip length considerably. This renders a textured microchannel with the particle-laden interface to be ineffective as compared to a completely wetted textured microchannel under certain conditions. Furthermore, a flow past two bi-dimensional textures, viz. posts and holes, with their interfaces embedded with spherical particles was also simulated. Our results show that texture configurations with an unbounded liquid-gas interface can mitigate the detrimental effects of particles adsorbed at the interface. The results presented here will help guide in designing efficient textured surfaces in future.

A theoretical model and phase field simulation on the evolution of interface roughness in the oxidation process

NASA Astrophysics Data System (ADS)

Yang, Fan; Fang, Dai-Ning; Liu, Bin

2012-01-01

An oxidation kinetics model is developed to account for the effects of the oxidation interface curvature and the oxidation-induced volume change or Pilling-Bedworth ratio. For the oxidation of Fe-Cr-Al-Y alloy fiber, the predictions agree well with experimental results. By considering the influence of the oxidation interface curvature on oxidation rates, the evolution of fluctuant oxidation interface is predicted. We also developed the phase field method (PFM) to simulate the evolution of the interface roughness. Both the theoretical model and the PFM results show that the interface will become smooth during high temperature oxidation. Stress distribution and evolution are calculated by PFM, which indicates that the stress level decreases as the interface morphology evolves.

A new apparatus for testing the delayed mechanical behaviour of interfaces: The Shearing Interfaces Creep box (SInC box)

NASA Astrophysics Data System (ADS)

Stavropoulou, Eleni; Briffaut, Matthieu; Dufour, Frédéric; Camps, Guillaume; Boulon, Marc

2017-06-01

A new experimental apparatus is presented for testing the time-dependent behaviour of interfaces, including in particular interfaces of geomaterials, under constant loading. This apparatus allows the application of two orthogonal loads normal and tangential to the mean plane of the interface, as well as the measurement of the axial and tangential relative displacements. The sample is moulded inside two half shear boxes and the system is designed in such a way that the shear force is applied along the mean plane of the interface. Some preliminary testing was carried out on a clay rock/concrete interface, under a controlled temperature environment. Preliminary results are presented, showing the evolution of the delayed displacements.

Object library for a new generation of experiment-controlling applications under the UNIX operating system.

PubMed

Gaponov, Y A; Ito, K; Amemiya, Y

1998-05-01

The Interface Object Library based on the Motif extension of the X Windows system and on the ESONE SVIC-VCC Library is presented. Some features of the applications for controlling a synchrotron radiation experiment are discussed. The Interface Object Library is written in the object-oriented C++ language. The library class-hierarchy structure is presented and discussed. Several interfaces were realized in the Interface Object Library: the Windows interface, the CAMAC interface and the interface for supporting the experiment. The behaviour of the objects describing the CAMAC crate and CAMAC block is discussed. The application of these protocols for controlling the fast one-coordinate position-sensitive X-ray detector OD3 is presented.

Model for interface formation and the resulting electrical properties for barium-strontium-titanate films on silicon

NASA Astrophysics Data System (ADS)

Mueller, A. H.; Suvorova, N. A.; Irene, E. A.; Auciello, O.; Schultz, J. A.

2003-04-01

The interface formation between sputtered barium strontium titanate (BST) films and both Si and SiO2 substrate surfaces has been followed using real-time spectroscopic ellipsometry and the mass spectrometry of recoiled ions. In both substrates an intermixed interface layer was observed and subcutaneous Si oxidation occurred. A model for the interface formation is proposed in which the interface includes an SiO2 film on Si, and an intermixed film on which is pure BST. During the deposition of BST the interfaces films were observed to change in time. Electrical characterization of the resulting metal-BST interface capacitors indicates that those samples with SiO2 on the Si surface had the best electrical characteristics.

Development of a simulated smart pump interface.

PubMed

Elias, Beth L; Moss, Jacqueline A; Shih, Alan; Dillavou, Marcus

2014-01-01

Medical device user interfaces are increasingly complex, resulting in a need for evaluation in clinicallyaccurate settings. Simulation of these interfaces can allow for evaluation, training, and use for research without the risk of harming patients and with a significant cost reduction over using the actual medical devices. This pilot project was phase 1 of a study to define and evaluate a methodology for development of simulated medical device interface technology to be used for education, device development, and research. Digital video and audio recordings of interface interactions were analyzed to develop a model of a smart intravenous medication infusion pump user interface. This model was used to program a high-fidelity simulated smart intravenous medication infusion pump user interface on an inexpensive netbook platform.

On the role of weak interface in crack blunting process in nanoscale layered composites

NASA Astrophysics Data System (ADS)

Li, Yi; Zhou, Qing; Zhang, Shuang; Huang, Ping; Xu, Kewei; Wang, Fei; Lu, Tianjian

2018-03-01

Heterointerface in a nanoscale metallic layered composite could improve its crack resistance. However, the influence of metallic interface structures on crack propagation has not been well understood at atomic scale. By using the method of molecular dynamics (MD) simulation, the crack propagation behavior in Cu-Nb bilayer is compared with that in Cu-Ni bilayer. We find that the weak Cu-Nb interface plays an important role in hindering crack propagation in two ways: (i) dislocation nucleation at the interface releases stress concentration for the crack to propagate; (ii) the easily sheared weak incoherent interface blunts the crack tip. The results are helpful for understanding the interface structure dependent crack resistance of nanoscale bicrystal interfaces.

Exchange bias mechanism in FM/FM/AF spin valve systems in the presence of random unidirectional anisotropy field at the AF interface: The role played by the interface roughness due to randomness

NASA Astrophysics Data System (ADS)

Yüksel, Yusuf

2018-05-01

We propose an atomistic model and present Monte Carlo simulation results regarding the influence of FM/AF interface structure on the hysteresis mechanism and exchange bias behavior for a spin valve type FM/FM/AF magnetic junction. We simulate perfectly flat and roughened interface structures both with uncompensated interfacial AF moments. In order to simulate rough interface effect, we introduce the concept of random exchange anisotropy field induced at the interface, and acting on the interface AF spins. Our results yield that different types of the random field distributions of anisotropy field may lead to different behavior of exchange bias.

Spacelab interface development test, volume 1, sections 1-6

NASA Technical Reports Server (NTRS)

Harris, L. H.

1979-01-01

Data recorded during the following tests is presented: pulse coded modulator master unit to Spacelab (S/L) interface, master timing unit to S/L interface, multiplexer-demultiplexer/serial input-output to S/L interface, and special tests.

Thesaurus-Enhanced Search Interfaces.

ERIC Educational Resources Information Center

Shiri, Ali Asghar; Revie, Crawford; Chowdhury, Gobinda

2002-01-01

Discussion of user interfaces to information retrieval systems focuses on interfaces that incorporate thesauri as part of their searching and browsing facilities. Discusses research literature related to information searching behavior, information retrieval interface evaluation, search term selection, and query expansion; and compares thesaurus…

Connections that Count: Brain-Computer Interface Enables the Profoundly Paralyzed to Communicate

MedlinePlus

... Home Current Issue Past Issues Connections that Count: Brain-Computer Interface Enables the Profoundly Paralyzed to Communicate ... of this page please turn Javascript on. A brain-computer interface (BCI) system This brain-computer interface ( ...

Revisiting the Al/Al₂O₃ interface: coherent interfaces and misfit accommodation.

PubMed

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

2014-03-27

We study the coherent and semi-coherent Al/α-Al2O3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1D) misfit dislocation model and a 2-dimensional (2D) dislocation network model have been studied. For the latter case, our analysis reveals an interface dislocation structure with a network of three sets of parallel dislocations, each with pure-edge character, giving rise to a pattern of coherent and stacking-fault-like regions at the interface. Structural relaxation at elevated temperatures leads to a further change of the dislocation pattern, which can be understood in terms of a competition between the stacking fault energy and the dislocation interaction energy at the interface. Our results are expected to serve as an input for the subsequent dislocation dynamics models to understand and predict the macroscopic mechanical behavior of Al/α-Al2O3 composite heterostructures.

'Fly Like This': Natural Language Interface for UAV Mission Planning

NASA Technical Reports Server (NTRS)

Chandarana, Meghan; Meszaros, Erica L.; Trujillo, Anna; Allen, B. Danette

2017-01-01

With the increasing presence of unmanned aerial vehicles (UAVs) in everyday environments, the user base of these powerful and potentially intelligent machines is expanding beyond exclusively highly trained vehicle operators to include non-expert system users. Scientists seeking to augment costly and often inflexible methods of data collection historically used are turning towards lower cost and reconfigurable UAVs. These new users require more intuitive and natural methods for UAV mission planning. This paper explores two natural language interfaces - gesture and speech - for UAV flight path generation through individual user studies. Subjects who participated in the user studies also used a mouse-based interface for a baseline comparison. Each interface allowed the user to build flight paths from a library of twelve individual trajectory segments. Individual user studies evaluated performance, efficacy, and ease-of-use of each interface using background surveys, subjective questionnaires, and observations on time and correctness. Analysis indicates that natural language interfaces are promising alternatives to traditional interfaces. The user study data collected on the efficacy and potential of each interface will be used to inform future intuitive UAV interface design for non-expert users.

Interface inequivalence of the InP/InAlAs/InP staggered double heterostructure grown by metalorganic chemical vapor deposition

NASA Astrophysics Data System (ADS)

Böhrer, J.; Krost, A.; Heitz, R.; Heinrichsdorff, F.; Eckey, L.; Bimberg, D.; Cerva, H.

1996-02-01

The optical and structural properties of the normal InAlAs on InP and the inverted InP on the InAlAs staggered band lineup interface grown by metalorganic chemical vapor deposition (MOCVD) are compared by use of transmission electron microscopy (TEM), time integrated, and time resolved photoluminescence. TEM images show that both interfaces are dissimilar. The normal interface is very abrupt. The inverted interface shows an additional graded layer of about 2.5 nm in width of In1-xAlxAsyP1-y with x (0.48-0) and y (1.0-0.0). A large optical anisotropy exists because of the inequivalence of the two interfaces. The larger spatial separation of the carriers at the inverted interface is responsible for a smaller overlap of the electron and hole wave functions and for that reason a one order of magnitude longer e-h luminescence decay time of 45 ns is observed. The normal interface transition shifts approximately to the third root of excitation while the inverted interface transition shifts logarithmically.

Interface Psychology: Touchscreens Change Attribute Importance, Decision Criteria, and Behavior in Online Choice

PubMed Central

Gips, James

2015-01-01

Abstract As the rise of tablets and smartphones move the dominant interface for digital content from mouse or trackpad to direct touchscreen interaction, work is needed to explore the role of interfaces in shaping psychological reactions to online content. This research explores the role of direct-touch interfaces in product search and choice, and isolates the touch element from other form factor changes such as screen size. Results from an experimental study using a travel recommendation Web site show that a direct-touch interface (vs. a more traditional mouse interface) increases the number of alternatives searched, and biases evaluations toward tangible attributes such as décor and furniture over intangible attributes such as WiFi and employee demeanor. Direct-touch interfaces also elevate the importance of internal and subjective satisfaction metrics such as instinct over external and objective metrics such as reviews, which in turn increases anticipated satisfaction metrics. Findings suggest that interfaces can strongly affect how online content is explored, perceived, remembered, and acted on, and further work in interface psychology could be as fruitful as research exploring the content itself. PMID:26348814

Thermal conductance at atomically clean and disordered silicon/aluminum interfaces: A molecular dynamics simulation study

NASA Astrophysics Data System (ADS)

Ih Choi, Woon; Kim, Kwiseon; Narumanchi, Sreekant

2012-09-01

Thermal resistance between layers impedes effective heat dissipation in electronics packaging applications. Thermal conductance for clean and disordered interfaces between silicon (Si) and aluminum (Al) was computed using realistic Si/Al interfaces and classical molecular dynamics with the modified embedded atom method potential. These realistic interfaces, which include atomically clean as well as disordered interfaces, were obtained using density functional theory. At 300 K, the magnitude of interfacial conductance due to phonon-phonon scattering obtained from the classical molecular dynamics simulations was approximately five times higher than the conductance obtained using analytical elastic diffuse mismatch models. Interfacial disorder reduced the thermal conductance due to increased phonon scattering with respect to the atomically clean interface. Also, the interfacial conductance, due to electron-phonon scattering at the interface, was greater than the conductance due to phonon-phonon scattering. This indicates that phonon-phonon scattering is the bottleneck for interfacial transport at the semiconductor/metal interfaces. The molecular dynamics modeling predictions for interfacial thermal conductance for a 5-nm disordered interface between Si/Al were in-line with recent experimental data in the literature.

Interface Psychology: Touchscreens Change Attribute Importance, Decision Criteria, and Behavior in Online Choice.

PubMed

Brasel, S Adam; Gips, James

2015-09-01

As the rise of tablets and smartphones move the dominant interface for digital content from mouse or trackpad to direct touchscreen interaction, work is needed to explore the role of interfaces in shaping psychological reactions to online content. This research explores the role of direct-touch interfaces in product search and choice, and isolates the touch element from other form factor changes such as screen size. Results from an experimental study using a travel recommendation Web site show that a direct-touch interface (vs. a more traditional mouse interface) increases the number of alternatives searched, and biases evaluations toward tangible attributes such as décor and furniture over intangible attributes such as WiFi and employee demeanor. Direct-touch interfaces also elevate the importance of internal and subjective satisfaction metrics such as instinct over external and objective metrics such as reviews, which in turn increases anticipated satisfaction metrics. Findings suggest that interfaces can strongly affect how online content is explored, perceived, remembered, and acted on, and further work in interface psychology could be as fruitful as research exploring the content itself.

Practical Life: The Keystone of Life, Culture, and Community

ERIC Educational Resources Information Center

Ramani, Uma

2013-01-01

Uma Ramani's characterization of practical life is philosophical and anthropological, suggesting that "human history is the story of the evolution of our practical life activities." Practical life is a collaborative activity that creates community and culture. One's adaptation to life through the daily work of ordering our environment…

Styles of Instructional Development.

ERIC Educational Resources Information Center

Cashell, Jane G.; And Others

The aspects of the team development style that were employed at the University of Mid-America (UMA) in developing multi-media instruction for a new and open university setting for adults are discussed in this paper. The experience of three team projects are drawn upon in defining some particular characteristics of internal team functioning and…

75 FR 36147 - Self-Regulatory Organizations; Chicago Board Options Exchange, Incorporated; Order Approving...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-24

..., as Modified by Amendment No. 1 Thereto, Related to the Hybrid Matching Algorithms June 17, 2010. On... Hybrid System. Each rule currently provides allocation algorithms the Exchange can utilize when executing incoming electronic orders, including the Ultimate Matching Algorithm (``UMA''), and price-time and pro...

Attitude and knowledge about foot health: a spanish view.

PubMed

López-López, Daniel; García-Mira, Ricardo; Palomo-López, Patricia; Sánchez-Gómez, Rubén; Ramos-Galván, José; Tovaruela-Carrión, Natalia; García-Sánchez, Matilde

2017-04-06

to explore attitudes towards patients' self-reported data about foot health-related beliefs from a behavioural and attitudinal perspective. a sample of 282 participants of a mean age of 39.46 ± 16.026 came to a health centre where self-reported demographic, clinical characteristics and beliefs relating to foot health data were registered, informants' completed all the stages of the research process. the results of the analysis revealed an 8-factor factorial structure based on (1) podiatric behaviours, (2) the intention to carry out protective behaviour, (3) attitudinal beliefs, (4) normative beliefs, (5) needs, (6) apathy, (7) self-care, and (8) the general perception of foot health. They all explained 62.78% of the variance, and were considered as independent variables in a regression analysis to determine which provided the best explanations for the importance attributed to foot health. the participants in the study revealed a positive attitude in relation to foot health care and responsible behaviour. explorar as atitudes em relação aos dados auto-relatados dos pacientes sobre crenças relacionadas à saúde do pé, desde uma perspectiva comportamental e atitudinal. uma amostra de 282 participantes com idade média de 39,46 ± 16,026 chegaram a um centro de saúde onde foram registradas características demográficas, clínicas e crenças auto-relatadas referentes a dados de saúde do pé, os quais completaram todas as fases do processo de pesquisa. os resultados da análise revelaram uma estrutura fatorial de 8 fatores baseada em (1) comportamentos podiátricos, (2) a intenção de realizar comportamentos protetores, (3) crenças atitudinais, (4) crenças normativas, (6) apatia, (7) autocuidado, e (8) a percepção geral da saúde do pé. Todos eles explicaram 62,78% da variância e foram considerados como variáveis ​​independentes em uma análise de regressão para determinar quais forneceram as melhores explicações para a importância atribuída à saúde do pé. os participantes do estudo revelaram uma atitude positiva em relação à saúde do pé e comportamento responsável. explorar las actitudes relacionadas con datos autoinformados sobre las creencias de la salud del pie desde una perspectiva actitudinal. una muestra de 282 participantes edad media 39.46 ± 16.026 acudieron a un centro de salud donde se registraron datos autoinformados de las características demográficas, características clínicas y creencias relacionadas con la salud del pie, completándose todas las etapas del proceso de investigación. los resultados del análisis revelaron una estructura factorial de 8 factores basado en (1) conductas podológicas, (2) la intención de llevar a cabo una conducta de protección, (3) las creencias actitudinales, (4) las creencias normativas, (5) las necesidades, (6) la apatía, (7) el autocuidado, y (8) la percepción general de salud podal. Todos ellos explicaron un 62,78% de la varianza, y fueron considerados como variables independientes en una ecuación de regresión para determinar cuáles de ellos explicaban mejor la importancia atribuida a la salud del pie. los participantes en el estudio revelaron una actitud positiva en relación al cuidado de la salud del pie y al comportamiento responsable.

Myosin-binding Protein C Compound Heterozygous Variant Effect on the Phenotypic Expression of Hypertrophic Cardiomyopathy.

PubMed

Rafael, Julianny Freitas; Cruz, Fernando Eugênio Dos Santos; Carvalho, Antônio Carlos Campos de; Gottlieb, Ilan; Cazelli, José Guilherme; Siciliano, Ana Paula; Dias, Glauber Monteiro

2017-04-01

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant genetic disease caused by mutations in genes encoding sarcomere proteins. It is the major cause of sudden cardiac death in young high-level athletes. Studies have demonstrated a poorer prognosis when associated with specific mutations. The association between HCM genotype and phenotype has been the subject of several studies since the discovery of the genetic nature of the disease. This study shows the effect of a MYBPC3 compound variant on the phenotypic HCM expression. A family in which a young man had a clinical diagnosis of HCM underwent clinical and genetic investigations. The coding regions of the MYH7, MYBPC3 and TNNT2 genes were sequenced and analyzed. The proband present a malignant manifestation of the disease, and is the only one to express HCM in his family. The genetic analysis through direct sequencing of the three main genes related to this disease identified a compound heterozygous variant (p.E542Q and p.D610H) in MYBPC3. A family analysis indicated that the p.E542Q and p.D610H alleles have paternal and maternal origin, respectively. No family member carrier of one of the variant alleles manifested clinical signs of HCM. We suggest that the MYBPC3-biallelic heterozygous expression of p.E542Q and p.D610H may cause the severe disease phenotype seen in the proband. Resumo A cardiomiopatia hipertrófica (CMH) é uma doença autossômica dominante causada por mutações em genes que codificam as proteínas dos sarcômeros. É a principal causa de morte súbita cardíaca em atletas jovens de alto nível. Estudos têm demonstrado um pior prognóstico associado a mutações específicas. A associação entre genótipo e fenótipo em CMH tem sido objeto de diversos estudos desde a descoberta da origem genética dessa doença. Este trabalho apresenta o efeito de uma mutação composta em MYBPC3 na expressão fenotípica da CMH. Uma família na qual um jovem tem o diagnóstico clínico de CMH foi submetida à investigação clínica e genética. As regiões codificadoras dos genes MYH7, MYBPC3 e TNNT2 foram sequenciadas e analisadas. O probando apresenta uma manifestação maligna da doença e é o único em sua família a desenvolver CMH. A análise genética pelo sequenciamento direto dos três principais genes relacionados à essa doença identificou uma variante em heterozigose composta (p.E542Q e p.D610H) em MYBPC3. A análise da família mostrou que os alelos p.E542Q e p.D610H tem origem paterna e materna, respectivamente. Nenhum familiar portador de um dos alelos variantes manifestou sinais clínicos de CMH. Sugerimos que a expressão heterozigótica bialélica de p.E542Q e p.D610H pode ser responsável pelo fenótipo severo da doença encontrada no probando.

Development and validation of the Hospitality Axiological Scale for Humanization of Nursing Care.

PubMed

Galán González-Serna, José María; Ferreras-Mencia, Soledad; Arribas-Marín, Juan Manuel

2017-08-03

to develop and validate a scale to evaluate nursing attitudes in relation to hospitality for the humanization of nursing care. Participants: the sample consisted of 499 nursing professionals and undergraduate students of the final two years of the Bachelor of Science in Nursing program. the instrument has been developed and validated to evaluate the ethical values related to hospitality using a methodological approach. Subsequently, a model was developed to measure the dimensions forming the construct hospitality. the Axiological Hospitality Scale showed a high internal consistency, with Cronbach's Alpha=0.901. The validation of the measuring instrument was performed using factorial, exploratory and confirmatory analysis techniques with high goodness of fit measures. the developed instrument showed an adequate validity and a high internal consistency. Based on the consistency of its psychometric properties, it is possible to affirm that the scale provides a reliable measurement of the hospitality. It was also possible to determine the dimensions or sources that embrace it: respect, responsibility, quality and transpersonal care. desenvolver e validar uma escala que permita avaliar a atitude dos enfermeiros em termos de hospitalidade, visando a humanização da enfermagem.Participantes: a amostra foi constituída por 499 profissionais e estudantes de enfermagem dos dois últimos anos do curso de graduação em Enfermagem. utilizando-seuma abordagem metodológica, foi desenvolvido e validado um instrumento para avaliar os valores éticos relacionados com a hospitalidade. Subsequentemente, foi formulado um modelo para mediras dimensões que constituem o construto hospitalidade. a Escala Axiológica de Hospitalidade mostrou uma consistência interna elevada, com Alfa de Cronbach=0,901. A validação do instrumento de medição foi realizada usando-se métodos de análise fatorial, exploratória e confirmatória, que apresentaram bons índices de qualidade de ajuste. o instrumento desenvolvido apresentou uma validade adequada e uma consistência interna elevada. Com base na consistência de suas propriedades psicométricas, é possível afirmar que a escala proporciona uma medida confiável da hospitalidade. Também foi possível determinar as dimensões ou fontes que a compõem: o respeito, a responsabilidade, a qualidade e o cuidado transpessoal. desarrollar y validar una escala que permita evaluar la actitud enfermera ante la hospitalidad para la humanización de enfermería. Participantes: la muestra la componen 499 profesionales de enfermería y estudiantes de los dos últimos niveles académicos de la titulación de Grado en Enfermería. mediante abordaje metodológico, se ha desarrollado y validado un instrumento para evaluar valores éticos relacionados con la hospitalidad. Posteriormente, se ha formulado un modelo de medida de las dimensiones que conforman el constructo hospitalidad. la Escala Axiológica de la Hospitalidad ha mostrado una alta consistencia interna, con un Alfa de Cronbach=0.901. La validación del instrumento de medida se realizó mediante las técnicas de análisis factorial, exploratorio y confirmatorio, que presentaron unos buenos índices de bondad de ajuste. el instrumento desarrollado ha presentado una adecuada validez y una alta consistencia interna. Sus adecuadas propiedades psicométricas permiten afirmar que la escala aporta una medición fiable de la hospitalidad. También ha permitido determinar las dimensiones o fuentes que la conforman: el respeto, la responsabilidad, la calidad y el cuidado transpersonal.

Providing Meaningful Learning for Students of the Sixth Grade of Middle School: a Study on the Moon Phases. (Breton Title: Propiciando Aprendizagem Significativa Para Alunos do Sexto Ano do Ensino Fundamental: um Estudo sobre as Fases da Lua.) Propiciando el Aprendizaje Significativo Para Alumnos del Sexto Nivel de la Educación General Básica: un Estudio sobre Las Fases de la Luna

NASA Astrophysics Data System (ADS)

Darroz, Luiz Marcelo; Samudio Pérez, Carlos Ariel; da Rosa, Cleci Werner; Heineck, Renato

2012-07-01

We relate in this article a didactic experience studying the moon phases with a group of middle school students of a private school of the municipality of Passo Fundo, RS. Based on David Ausubel's Meaningful Learning Theory, we have sought to develop a proposal following a didactic model which simulates the phases of the Moon, as based on the previous conceptions of the students. The signs of learning were evidenced by means of memory registries of the activity. From the obtained results we believe that the proposal achieved its goals, since the students were able to identify, differentiate and transfer the phenomenon of the moon phases to new contexts. Thus, it is concluded that a methodology focused on a meaningful content for the students is fundamental to the construction and genuine grasping of what is being learned. Neste artigo, relata-se uma experiência didática de estudo das fases da Lua com uma turma do 6° ano do Ensino Fundamental, de uma escola privada do município de Passo Fundo, RS. Tendo como fundamentação teórica a Teoria da Aprendizagem Significativa de David Ausubel, buscou-se desenvolver a proposta a partir de um modelo didático que simula as fases da Lua e com base nas concepções prévias dos estudantes. Os indícios da aprendizagem foram constatados através de registros de memórias da atividade. Pelos resultados apresentados, acredita-se que a proposta alcançou seus objetivos, uma vez que os estudantes conseguiram identificar, diferenciar e transferir o fenômeno das fases da Lua para novos contextos. Assim, conclui-se que uma metodologia com enfoque em um conteúdo significativo ao estudante é fundamental para a construção e compreensão genuína do que está sendo aprendido. En este artículo se relata una experiencia didáctica de estudio de las fases de la Luna con una clase de 6º año de la educación general básica de una escuela privada del municipio de Passo Fundo, RS. Teniendo como fundamentación teórica la Teoría del Aprendizaje Significativo de David Ausubel, se buscó desenvolver la propuesta a partir de un modelo didáctico que simula las Fases de la Luna, usando como base las concepciones previas de los estudiantes. Los indicios del aprendizaje fueron verificados a través de registros de memorias de la actividad. Por los resultados obtenidos creemos que la propuesta alcanzó sus objetivos, una vez que los estudiantes consiguieron identificar y transferir el fenómeno de las fases de la Luna para nuevos contextos. Así, se concluye que una metodología con enfoque en un contenido significativo para el estudiante es fundamental para la construcción y comprensión genuina de lo que está siendo aprendido.

Assessing the Usability of Six Data Entry Mobile Interfaces for Caregivers: A Randomized Trial.

PubMed

Ehrler, Frederic; Haller, Guy; Sarrey, Evelyne; Walesa, Magali; Wipfli, Rolf; Lovis, Christian

2015-12-15

There is an increased demand in hospitals for tools, such as dedicated mobile device apps, that enable the recording of clinical information in an electronic format at the patient's bedside. Although the human-machine interface design on mobile devices strongly influences the accuracy and effectiveness of data recording, there is still a lack of evidence as to which interface design offers the best guarantee for ease of use and quality of recording. Therefore, interfaces need to be assessed both for usability and reliability because recording errors can seriously impact the overall level of quality of the data and affect the care provided. In this randomized crossover trial, we formally compared 6 handheld device interfaces for both speed of data entry and accuracy of recorded information. Three types of numerical data commonly recorded at the patient's bedside were used to evaluate the interfaces. In total, 150 health care professionals from the University Hospitals of Geneva volunteered to record a series of randomly generated data on each of the 6 interfaces provided on a smartphone. The interfaces were presented in a randomized order as part of fully automated data entry scenarios. During the data entry process, accuracy and effectiveness were automatically recorded by the software. Various types of errors occurred, which ranged from 0.7% for the most reliable design to 18.5% for the least reliable one. The length of time needed for data recording ranged from 2.81 sec to 14.68 sec, depending on the interface. The numeric keyboard interface delivered the best performance for pulse data entry with a mean time of 3.08 sec (SD 0.06) and an accuracy of 99.3%. Our study highlights the critical impact the choice of an interface can have on the quality of recorded data. Selecting an interface should be driven less by the needs of specific end-user groups or the necessity to facilitate the developer's task (eg, by opting for default solutions provided by commercial platforms) than by the level of speed and accuracy an interface can provide for recording information. An important effort must be made to properly validate mobile device interfaces intended for use in the clinical setting. In this regard, our study identified the numeric keyboard, among the proposed designs, as the most accurate interface for entering specific numerical values. This is an important step toward providing clearer guidelines on which interface to choose for the appropriate use of handheld device interfaces in the health care setting.

Assessing the Usability of Six Data Entry Mobile Interfaces for Caregivers: A Randomized Trial

PubMed Central

Haller, Guy; Sarrey, Evelyne; Walesa, Magali; Wipfli, Rolf; Lovis, Christian

2015-01-01

Background There is an increased demand in hospitals for tools, such as dedicated mobile device apps, that enable the recording of clinical information in an electronic format at the patient’s bedside. Although the human-machine interface design on mobile devices strongly influences the accuracy and effectiveness of data recording, there is still a lack of evidence as to which interface design offers the best guarantee for ease of use and quality of recording. Therefore, interfaces need to be assessed both for usability and reliability because recording errors can seriously impact the overall level of quality of the data and affect the care provided. Objective In this randomized crossover trial, we formally compared 6 handheld device interfaces for both speed of data entry and accuracy of recorded information. Three types of numerical data commonly recorded at the patient’s bedside were used to evaluate the interfaces. Methods In total, 150 health care professionals from the University Hospitals of Geneva volunteered to record a series of randomly generated data on each of the 6 interfaces provided on a smartphone. The interfaces were presented in a randomized order as part of fully automated data entry scenarios. During the data entry process, accuracy and effectiveness were automatically recorded by the software. Results Various types of errors occurred, which ranged from 0.7% for the most reliable design to 18.5% for the least reliable one. The length of time needed for data recording ranged from 2.81 sec to 14.68 sec, depending on the interface. The numeric keyboard interface delivered the best performance for pulse data entry with a mean time of 3.08 sec (SD 0.06) and an accuracy of 99.3%. Conclusions Our study highlights the critical impact the choice of an interface can have on the quality of recorded data. Selecting an interface should be driven less by the needs of specific end-user groups or the necessity to facilitate the developer’s task (eg, by opting for default solutions provided by commercial platforms) than by the level of speed and accuracy an interface can provide for recording information. An important effort must be made to properly validate mobile device interfaces intended for use in the clinical setting. In this regard, our study identified the numeric keyboard, among the proposed designs, as the most accurate interface for entering specific numerical values. This is an important step toward providing clearer guidelines on which interface to choose for the appropriate use of handheld device interfaces in the health care setting. PMID:27025648

Sociable Interfaces

DTIC Science & Technology

2005-01-01

Interface Compatibility); the tool is written in Ocaml [10], and the symbolic algorithms for interface compatibility and refinement are built on top...automata for a fire detection and reporting system. be encoded in the input language of the tool TIC. The refinement of sociable interfaces is discussed...are closely related to the I/O Automata Language (IOA) of [11]. Interface models are games between Input and Output, and in the models, it is es

Effect of Microstructure on the Strength and Fracture Energy of Bimaterial Interfaces.

DTIC Science & Technology

1992-12-31

Bimaterials Interfaces includes three sections: Mechanics of Interfaces, Coating Design for Composite Systems, and Mechanics of Brittle Matrix... Composites . For more details see Executive Summary. 14. SUBJECT TERM 15. NUMBER OF PAGES Effect, Microstructure, Strength, Fracture Energy, Bimatenal...The Role of Interfaces in Fiber-Reinforced Brittle A.G. Evans Matrix Composites F.W. Zok J.B. Davis Article 2. Effects of Fiber Roughness on Interface

Implementing a Quantitative Analysis Design Tool for Future Generation Interfaces

DTIC Science & Technology

2012-03-01

with Remotely Piloted Aircraft (RPA) has resulted in the need of a platform to evaluate interface design. The Vigilant Spirit Control Station ( VSCS ...Spirit interface. A modified version of the HCI Index was successfully applied to perform a quantitative analysis of the baseline VSCS interface and...time of the original VSCS interface. These results revealed the effectiveness of the tool and demonstrated in the design of future generation

Media independent interface. Interface control document

NASA Technical Reports Server (NTRS)

1987-01-01

A Media Independent Interface (MII) is specified, using current standards in the industry. The MII is described in hierarchical fashion. At the base are IEEE/International Standards Organization (ISO) documents (standards) which describe the functionality of the software modules or layers and their interconnection. These documents describe primitives which are to transcent the MII. The intent of the MII is to provide a universal interface to one or more Media Access Contols (MACs) for the Logical Link Controller and Station Manager. This interface includes both a standardized electrical and mechanical interface and a standardized functional specification which defines the services expected from the MAC.

Intelligent subsystem interface for modular hardware system

NASA Technical Reports Server (NTRS)

Caffrey, Robert T. (Inventor); Krening, Douglas N. (Inventor); Lannan, Gregory B. (Inventor); Schneiderwind, Michael J. (Inventor); Schneiderwind, Robert A. (Inventor)

2000-01-01

A single chip application specific integrated circuit (ASIC) which provides a flexible, modular interface between a subsystem and a standard system bus. The ASIC includes a microcontroller/microprocessor, a serial interface for connection to the bus, and a variety of communications interface devices available for coupling to the subsystem. A three-bus architecture, utilizing arbitration, provides connectivity within the ASIC and between the ASIC and the subsystem. The communication interface devices include UART (serial), parallel, analog, and external device interface utilizing bus connections paired with device select signals. A low power (sleep) mode is provided as is a processor disable option.

Analysis of interface crack branching

NASA Technical Reports Server (NTRS)

Ballarini, R.; Mukai, D. J.; Miller, G. R.

1989-01-01

A solution is presented for the problem of a finite length crack branching off the interface between two bonded dissimilar isotropic materials. Results are presented in terms of the ratio of the energy release rate of a branched interface crack to the energy release rate of a straight interface crack with the same total length. It is found that this ratio reaches a maximum when the interface crack branches into the softer material. Longer branches tend to have smaller maximum energy release rate ratio angles indicating that all else being equal, a branch crack will tend to turn back parallel to the interface as it grows.

Observation of interface carrier states in no-common-atom heterostructures ZnSe/BeTe.

PubMed

Gurevich, A S; Kochereshko, V P; Bleuse, J; Mariette, H; Waag, A; Akimoto, R

2011-09-07

The existence of intrinsic carrier interface states in heterostructures with no common atom at the interface (such as ZnSe/BeTe) is shown experimentally by ellipsometry and photoluminescence spectroscopy. These states are located on interfaces and lie inside the effective bandgap of the structure; they are characterized by a high density and a long lifetime. A tight binding model confirms theoretically the existence of these states in ZnSe/BeTe heterostructures for a ZnTe-type interface, in contrast to the case of the BeSe-type interface for which they do not exist.

Observation of interface carrier states in no-common-atom heterostructures ZnSe/BeTe

NASA Astrophysics Data System (ADS)

Gurevich, A. S.; Kochereshko, V. P.; Bleuse, J.; Mariette, H.; Waag, A.; Akimoto, R.

2011-09-01

The existence of intrinsic carrier interface states in heterostructures with no common atom at the interface (such as ZnSe/BeTe) is shown experimentally by ellipsometry and photoluminescence spectroscopy. These states are located on interfaces and lie inside the effective bandgap of the structure; they are characterized by a high density and a long lifetime. A tight binding model confirms theoretically the existence of these states in ZnSe/BeTe heterostructures for a ZnTe-type interface, in contrast to the case of the BeSe-type interface for which they do not exist.

A web based Radiation Oncology Dose Manager with a rich User Interface developed using AJAX, ruby, dynamic XHTML and the new Yahoo/EXT User Interface Library.

PubMed

Vali, Faisal; Hong, Robert

2007-10-11

With the evolution of AJAX, ruby on rails, advanced dynamic XHTML technologies and the advent of powerful user interface libraries for javascript (EXT, Yahoo User Interface Library), developers now have the ability to provide truly rich interfaces within web browsers, with reasonable effort and without third-party plugins. We designed and developed an example of such a solution. The User Interface allows radiation oncology practices to intuitively manage different dose fractionation schemes by helping estimate total dose to irradiated organs.

Experimental study of an isochorically heated heterogeneous interface. A progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez, Juan Carlos

2015-08-20

Outline of the presentation: Studying possible mix / interface motion between heterogeneous low/high Z interfaces driven by 2-fluid or kinetic plasma effects (Heated to few eV, Sharp (sub µm) interface); Isochoric heating to initialize interface done with Al quasimonoenergetic ion beams on Trident; Have measured isochoric heating in individual materials intended for compound targets; Fielded experiments on Trident to measure interface motion (Gold-diamond, tin-aluminium); Measured heated-sample temperature with streaked optical pyrometry (SOP) (UT Austin led (research contract), SOP tests → heating uniformity Vs thickness on Al foils. Results are being analyzed.

An operator interface design for a telerobotic inspection system

NASA Technical Reports Server (NTRS)

Kim, Won S.; Tso, Kam S.; Hayati, Samad

1993-01-01

The operator interface has recently emerged as an important element for efficient and safe interactions between human operators and telerobotics. Advances in graphical user interface and graphics technologies enable us to produce very efficient operator interface designs. This paper describes an efficient graphical operator interface design newly developed for remote surface inspection at NASA-JPL. The interface, designed so that remote surface inspection can be performed by a single operator with an integrated robot control and image inspection capability, supports three inspection strategies of teleoperated human visual inspection, human visual inspection with automated scanning, and machine-vision-based automated inspection.

A density functional study of the effect of hydrogen on electronic properties and band discontinuity at anatase TiO2/diamond interface

NASA Astrophysics Data System (ADS)

Wu, Kongping; Liao, Meiyong; Sang, Liwen; Liu, Jiangwei; Imura, Masataka; Ye, Haitao; Koide, Yasuo

2018-04-01

Tailoring the electronic states of the dielectric oxide/diamond interface is critical to the development of next generation semiconductor devices like high-power high-frequency field-effect transistors. In this work, we investigate the electronic states of the TiO2/diamond 2 × 1-(100) interface by using first principles total energy calculations. Based on the calculation of the chemical potentials for the TiO2/diamond interface, it is observed that the hetero-interfaces with the C-OTi configuration or with two O vacancies are the most energetically favorable structures under the O-rich condition and under Ti-rich condition, respectively. The band structure and density of states of both TiO2/diamond and TiO2/H-diamond hetero-structures are calculated. It is revealed that there are considerable interface states at the interface of the anatase TiO2/diamond hetero-structure. By introducing H on the diamond surface, the interface states are significantly suppressed. A type-II alignment band structure is disclosed at the interface of the TiO2/diamond hetero-structure. The valence band offset increases from 0.6 to 1.7 eV when H is introduced at the TiO2/diamond interface.

Deformation response of cube-on-cube and non-coherent twin interfaces in AgCu eutectic after dynamic plastic compression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eftink, Benjamin P.; Mara, Nathan Allan; Kingstedt, Owen T.

For this research, Split-Hopkinson pressure bar dynamic compression experiments were conducted to determine the defect/interface interaction dependence on interface type, bilayer thickness and interface orientation with respect to the loading direction in the Ag-Cu eutectic system. Specifically, the deformation microstructure in alloys with either a cube-on-cube orientation relationship with {111} Ag||{111} Cu interface habit planes or a twin orientation relationship with {more » $$\\overline{3}13$$} Ag||{$$\\overline{1}12$$} Cu interface habit planes and with bilayer thicknesses of 500 nm, 1.1 µm and 2.2 µm were probed using TEM. The deformation was carried by dislocation slip and in certain conditions, deformation twinning. The twinning response was dependent on loading orientation with respect to the interface plane, bilayer thickness, and interface type. Twinning was only observed when loading at orientations away from the growth direction and decreased in prevalence with decreasing bilayer thickness. Twinning in Cu was dependent on twinning partial dislocations being transmitted from Ag, which only occurred for cube-on-cube interfaces. Lastly, dislocation slip and deformation twin transfer across the interfaces is discussed in terms of the slip transfer conditions developed for grain boundaries in FCC alloys.« less

Deformation response of cube-on-cube and non-coherent twin interfaces in AgCu eutectic after dynamic plastic compression

DOE PAGES

Eftink, Benjamin P.; Mara, Nathan Allan; Kingstedt, Owen T.; ...

2017-12-02

For this research, Split-Hopkinson pressure bar dynamic compression experiments were conducted to determine the defect/interface interaction dependence on interface type, bilayer thickness and interface orientation with respect to the loading direction in the Ag-Cu eutectic system. Specifically, the deformation microstructure in alloys with either a cube-on-cube orientation relationship with {111} Ag||{111} Cu interface habit planes or a twin orientation relationship with {more » $$\\overline{3}13$$} Ag||{$$\\overline{1}12$$} Cu interface habit planes and with bilayer thicknesses of 500 nm, 1.1 µm and 2.2 µm were probed using TEM. The deformation was carried by dislocation slip and in certain conditions, deformation twinning. The twinning response was dependent on loading orientation with respect to the interface plane, bilayer thickness, and interface type. Twinning was only observed when loading at orientations away from the growth direction and decreased in prevalence with decreasing bilayer thickness. Twinning in Cu was dependent on twinning partial dislocations being transmitted from Ag, which only occurred for cube-on-cube interfaces. Lastly, dislocation slip and deformation twin transfer across the interfaces is discussed in terms of the slip transfer conditions developed for grain boundaries in FCC alloys.« less

Conceptualization and application of an approach for designing healthcare software interfaces.

PubMed

Kumar, Ajit; Maskara, Reena; Maskara, Sanjeev; Chiang, I-Jen

2014-06-01

The aim of this study is to conceptualize a novel approach, which facilitates us to design prototype interfaces for healthcare software. Concepts and techniques from various disciplines were used to conceptualize an interface design approach named MORTARS (Map Original Rhetorical To Adapted Rhetorical Situation). The concepts and techniques included in this approach are (1) rhetorical situation - a concept of philosophy provided by Bitzer (1968); (2) move analysis - an applied linguistic technique provided by Swales (1990) and Bhatia (1993); (3) interface design guidelines - a cognitive and computer science concept provided by Johnson (2010); (4) usability evaluation instrument - an interface evaluation questionnaire provided by Lund (2001); (5) user modeling via stereotyping - a cognitive and computer science concept provided by Rich (1979). A prototype interface for outpatient clinic software was designed to introduce the underlying concepts of MORTARS. The prototype interface was evaluated by thirty-two medical informaticians. The medical informaticians found the designed prototype interface to be useful (73.3%), easy to use (71.9%), easy to learn (93.1%), and satisfactory (53.2%). MORTARS approach was found to be effective in designing the prototype user interface for the outpatient clinic software. This approach might be further used to design interfaces for various software pertaining to healthcare and other domains. Copyright © 2014 Elsevier Inc. All rights reserved.

JAIL: a structure-based interface library for macromolecules.

PubMed

Günther, Stefan; von Eichborn, Joachim; May, Patrick; Preissner, Robert

2009-01-01

The increasing number of solved macromolecules provides a solid number of 3D interfaces, if all types of molecular contacts are being considered. JAIL annotates three different kinds of macromolecular interfaces, those between interacting protein domains, interfaces of different protein chains and interfaces between proteins and nucleic acids. This results in a total number of about 184,000 database entries. All the interfaces can easily be identified by a detailed search form or by a hierarchical tree that describes the protein domain architectures classified by the SCOP database. Visual inspection of the interfaces is possible via an interactive protein viewer. Furthermore, large scale analyses are supported by an implemented sequential and by a structural clustering. Similar interfaces as well as non-redundant interfaces can be easily picked out. Additionally, the sequential conservation of binding sites was also included in the database and is retrievable via Jmol. A comprehensive download section allows the composition of representative data sets with user defined parameters. The huge data set in combination with various search options allow a comprehensive view on all interfaces between macromolecules included in the Protein Data Bank (PDB). The download of the data sets supports numerous further investigations in macromolecular recognition. JAIL is publicly available at http://bioinformatics.charite.de/jail.

Role of Interfaces in Elasticity and Failure of Clay-Organic Nanocomposites: Toughening upon Interface Weakening?

PubMed

Hantal, György; Brochard, Laurent; Pellenq, Roland J-M; Ulm, Franz-Joseph; Coasne, Benoit

2017-10-24

Synthetic organic-inorganic composites constitute a new class of engineering materials finding applications in an increasing range of fields. The interface between the constituting phases plays a pivotal role in the enhancement of mechanical properties. In exfoliated clay-organic nanocomposites, individual, high aspect ratio clay sheets are dispersed in the organic matrix providing large interfaces and hence efficient stress transfer. In this study, we aim at elucidating molecular-scale reinforcing mechanisms in a series of model clay-organic composite systems by means of reactive molecular simulations. In our models, two possible locations of failure initiation are present: one is the interlayer space of the clay platelet, and the other one is the clay-organic interface. We systematically modify the cohesiveness of the interface and assess how the failure mechanism changes when the different model composites are subjected to a tensile test. Besides a change in the failure mechanism, an increase in the released energy at the interface (meaning an increased overall toughness) are observed upon weakening the interface by bond removal. We propose a theoretical analysis of these results by considering a cohesive law that captures the effect of the interface on the composite mechanics. We suggest an atomistic interpretation of this cohesive law, in particular, how it relates to the degree of bonding at the interface. In a broader perspective, this work sheds light on the importance of the orthogonal behavior of interfaces to nanocomposites.

[Virus adsorption from batch experiments as influenced by air-water interface].

PubMed

Zhang, Hui; Zhao, Bing-zi; Zhang, Jia-bao; Zhang, Cong-zhi; Wang, Qiu-ying; Chen, Ji

2007-12-01

The presence of air-water interface in batch sorption experiments may result in inaccurate estimation of virus adsorption onto various soils. A batch sorption experiment was conducted to compare the adsorption results of MS2 in different soils under presence/absence of air-water interface. Soils with sterilization/nonterilization treatment were used. Virus recovery efficiency in a blank experiment (no soil) was also evaluated as affected by different amount of air-water interface. The presence of air-water interface altered the results of virus adsorption in different soils with different extent, with Sandy fluvo-aquic soil being the most considerably affected, followed by Red loam soil, and the least being Red clay soil, probably because of different soil properties associated with virus adsorption/inactivation. Soil sterilization resulted in more significant difference of virus adsorption onto the Sandy fluvo-aquic soil between the presence and absence of air-water interface, while a reduced difference was observed in the Red loam soil. The presence of air-water interface significantly decreased virus recovery efficiency, with the values being decreased with increase in the amount of air-water interface. Soil particles likely prohibit viruses from reaching the air-water interface or alter the forces at the solid-water-air interface so that the results from the blank experiment did not truly represent results from control blank, which probably resulted in adsorption difference between presence and absence of the air-water interface.

Comparison of two kinds of interface, based on guided navigation or usability principles, for improving the adoption of computerized decision support systems: application to the prescription of antibiotics.

PubMed

Tsopra, Rosy; Jais, Jean-Philippe; Venot, Alain; Duclos, Catherine

2014-02-01

It is important to consider the way in which information is presented by the interfaces of clinical decision support systems, to favor the adoption of these systems by physicians. Interface design can focus on decision processes (guided navigation) or usability principles. The aim of this study was to compare these two approaches in terms of perceived usability, accuracy rate, and confidence in the system. We displayed clinical practice guidelines for antibiotic treatment via two types of interface, which we compared in a crossover design. General practitioners were asked to provide responses for 10 clinical cases and the System Usability Scale (SUS) for each interface. We assessed SUS scores, the number of correct responses, and the confidence level for each interface. SUS score and percentage confidence were significantly higher for the interface designed according to usability principles (81 vs 51, p=0.00004, and 88.8% vs 80.7%, p=0.004). The percentage of correct responses was similar for the two interfaces. The interface designed according to usability principles was perceived to be more usable and inspired greater confidence among physicians than the guided navigation interface. Consideration of usability principles in the construction of an interface--in particular 'effective information presentation', 'consistency', 'efficient interactions', 'effective use of language', and 'minimizing cognitive load'--seemed to improve perceived usability and confidence in the system.

A 2-D Interface Element for Coupled Analysis of Independently Modeled 3-D Finite Element Subdomains

NASA Technical Reports Server (NTRS)

Kandil, Osama A.

1998-01-01

Over the past few years, the development of the interface technology has provided an analysis framework for embedding detailed finite element models within finite element models which are less refined. This development has enabled the use of cascading substructure domains without the constraint of coincident nodes along substructure boundaries. The approach used for the interface element is based on an alternate variational principle often used in deriving hybrid finite elements. The resulting system of equations exhibits a high degree of sparsity but gives rise to a non-positive definite system which causes difficulties with many of the equation solvers in general-purpose finite element codes. Hence the global system of equations is generally solved using, a decomposition procedure with pivoting. The research reported to-date for the interface element includes the one-dimensional line interface element and two-dimensional surface interface element. Several large-scale simulations, including geometrically nonlinear problems, have been reported using the one-dimensional interface element technology; however, only limited applications are available for the surface interface element. In the applications reported to-date, the geometry of the interfaced domains exactly match each other even though the spatial discretization within each domain may be different. As such, the spatial modeling of each domain, the interface elements and the assembled system is still laborious. The present research is focused on developing a rapid modeling procedure based on a parametric interface representation of independently defined subdomains which are also independently discretized.

A sharp interface method for compressible liquid–vapor flow with phase transition and surface tension

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fechter, Stefan, E-mail: stefan.fechter@iag.uni-stuttgart.de; Munz, Claus-Dieter, E-mail: munz@iag.uni-stuttgart.de; Rohde, Christian, E-mail: Christian.Rohde@mathematik.uni-stuttgart.de

The numerical approximation of non-isothermal liquid–vapor flow within the compressible regime is a difficult task because complex physical effects at the phase interfaces can govern the global flow behavior. We present a sharp interface approach which treats the interface as a shock-wave like discontinuity. Any mixing of fluid phases is avoided by using the flow solver in the bulk regions only, and a ghost-fluid approach close to the interface. The coupling states for the numerical solution in the bulk regions are determined by the solution of local two-phase Riemann problems across the interface. The Riemann solution accounts for the relevantmore » physics by enforcing appropriate jump conditions at the phase boundary. A wide variety of interface effects can be handled in a thermodynamically consistent way. This includes surface tension or mass/energy transfer by phase transition. Moreover, the local normal speed of the interface, which is needed to calculate the time evolution of the interface, is given by the Riemann solution. The interface tracking itself is based on a level-set method. The focus in this paper is the description of the two-phase Riemann solver and its usage within the sharp interface approach. One-dimensional problems are selected to validate the approach. Finally, the three-dimensional simulation of a wobbling droplet and a shock droplet interaction in two dimensions are shown. In both problems phase transition and surface tension determine the global bulk behavior.« less

Protein-Protein Interface Predictions by Data-Driven Methods: A Review

PubMed Central

Xue, Li C; Dobbs, Drena; Bonvin, Alexandre M.J.J.; Honavar, Vasant

2015-01-01

Reliably pinpointing which specific amino acid residues form the interface(s) between a protein and its binding partner(s) is critical for understanding the structural and physicochemical determinants of protein recognition and binding affinity, and has wide applications in modeling and validating protein interactions predicted by high-throughput methods, in engineering proteins, and in prioritizing drug targets. Here, we review the basic concepts, principles and recent advances in computational approaches to the analysis and prediction of protein-protein interfaces. We point out caveats for objectively evaluating interface predictors, and discuss various applications of data-driven interface predictors for improving energy model-driven protein-protein docking. Finally, we stress the importance of exploiting binding partner information in reliably predicting interfaces and highlight recent advances in this emerging direction. PMID:26460190

Key-value store with internal key-value storage interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bent, John M.; Faibish, Sorin; Ting, Dennis P. J.

A key-value store is provided having one or more key-value storage interfaces. A key-value store on at least one compute node comprises a memory for storing a plurality of key-value pairs; and an abstract storage interface comprising a software interface module that communicates with at least one persistent storage device providing a key-value interface for persistent storage of one or more of the plurality of key-value pairs, wherein the software interface module provides the one or more key-value pairs to the at least one persistent storage device in a key-value format. The abstract storage interface optionally processes one or moremore » batch operations on the plurality of key-value pairs. A distributed embodiment for a partitioned key-value store is also provided.« less

First-principles approach to calculating energy level alignment at aqueous semiconductor interfaces.

PubMed

Kharche, Neerav; Muckerman, James T; Hybertsen, Mark S

2014-10-24

A first-principles approach is demonstrated for calculating the relationship between an aqueous semiconductor interface structure and energy level alignment. The physical interface structure is sampled using density functional theory based molecular dynamics, yielding the interface electrostatic dipole. The  GW approach from many-body perturbation theory is used to place the electronic band edge energies of the semiconductor relative to the occupied 1b1 energy level in water. The application to the specific cases of nonpolar (101¯0) facets of GaN and ZnO reveals a significant role for the structural motifs at the interface, including the degree of interface water dissociation and the dynamical fluctuations in the interface Zn-O and O-H bond orientations. These effects contribute up to 0.5 eV.

User interface support

NASA Technical Reports Server (NTRS)

Lewis, Clayton; Wilde, Nick

1989-01-01

Space construction will require heavy investment in the development of a wide variety of user interfaces for the computer-based tools that will be involved at every stage of construction operations. Using today's technology, user interface development is very expensive for two reasons: (1) specialized and scarce programming skills are required to implement the necessary graphical representations and complex control regimes for high-quality interfaces; (2) iteration on prototypes is required to meet user and task requirements, since these are difficult to anticipate with current (and foreseeable) design knowledge. We are attacking this problem by building a user interface development tool based on extensions to the spreadsheet model of computation. The tool provides high-level support for graphical user interfaces and permits dynamic modification of interfaces, without requiring conventional programming concepts and skills.

Command and control interfaces for advanced neuroprosthetic applications.

PubMed

Scott, T R; Haugland, M

2001-10-01

Command and control interfaces permit the intention and situation of the user to influence the operation of the neural prosthesis. The wishes of the user are communicated via command interfaces to the neural prosthesis and the situation of the user by feedback control interfaces. Both these interfaces have been reviewed separately and are discussed in light of the current state of the art and projections for the future. It is apparent that as system functional complexity increases, the need for simpler command interfaces will increase. Such systems will demand more information to function effectively in order not to unreasonably increase user attention overhead. This will increase the need for bioelectric and biomechanical signals in a comprehensible form via elegant feedback control interfaces. Implementing such systems will also increase the computational demand on such neural prostheses.

Interface-facilitated energy transport in coupled Frenkel-Kontorova chains

NASA Astrophysics Data System (ADS)

Su, Rui-Xia; Yuan, Zong-Qiang; Wang, Jun; Zheng, Zhi-Gang

2016-04-01

The role of interface couplings on the energy transport of two coupled Frenkel-Kontorova (FK) chains is explored through numerical simulations. In general, it is expected that the interface couplings result in the suppression of heat conduction through the coupled system due to the additional interface phonon-phonon scattering. In the present paper, it is found that the thermal conductivity increases with increasing intensity of interface interactions for weak inter-chain couplings, whereas the heat conduction is suppressed by the interface interaction in the case of strong inter-chain couplings. Based on the phonon spectral energy density method, we demonstrate that the enhancement of energy transport results from the excited phonon modes (in addition to the intrinsic phonon modes), while the strong interface phonon-phonon scattering results in the suppressed energy transport.

Microfluidic PMMA interfaces for rectangular glass capillaries

NASA Astrophysics Data System (ADS)

Evander, Mikael; Tenje, Maria

2014-02-01

We present the design and fabrication of a polymeric capillary fluidic interface fabricated by micro-milling. The design enables the use of glass capillaries with any kind of cross-section in complex microfluidic setups. We demonstrate two different designs of the interface; a double-inlet interface for hydrodynamic focusing and a capillary interface with integrated pneumatic valves. Both capillary interfaces are presented together with examples of practical applications. This communication shows the design optimization and presents details of the fabrication process. The capillary interface opens up for the use of complex microfluidic systems in single-use glass capillaries. They also enable simple fabrication of glass/polymer hybrid devices that can be beneficial in many research fields where a pure polymer chip negatively affects the device's performance, e.g. acoustofluidics.

Horizontal shear wave scattering from a nonwelded interface observed by magnetic resonance elastography

NASA Astrophysics Data System (ADS)

Papazoglou, S.; Hamhaber, U.; Braun, J.; Sack, I.

2007-02-01

A method based on magnetic resonance elastography is presented that allows measuring the weldedness of interfaces between soft tissue layers. The technique exploits the dependence of shear wave scattering at elastic interfaces on the frequency of vibration. Experiments were performed on gel phantoms including differently welded interfaces. Plane wave excitation parallel to the planar interface with corresponding motion sensitization enabled the observation of only shear-horizontal (SH) wave scattering. Spatio-temporal filtering was applied to calculate scattering coefficients from the amplitudes of the incident, transmitted and reflected SH-waves in the vicinity of the interface. The results illustrate that acoustic wave scattering in soft tissues is largely dependent on the connectivity of interfaces, which is potentially interesting for imaging tissue mechanics in medicine and biology.

HotRegion: a database of predicted hot spot clusters.

PubMed

Cukuroglu, Engin; Gursoy, Attila; Keskin, Ozlem

2012-01-01

Hot spots are energetically important residues at protein interfaces and they are not randomly distributed across the interface but rather clustered. These clustered hot spots form hot regions. Hot regions are important for the stability of protein complexes, as well as providing specificity to binding sites. We propose a database called HotRegion, which provides the hot region information of the interfaces by using predicted hot spot residues, and structural properties of these interface residues such as pair potentials of interface residues, accessible surface area (ASA) and relative ASA values of interface residues of both monomer and complex forms of proteins. Also, the 3D visualization of the interface and interactions among hot spot residues are provided. HotRegion is accessible at http://prism.ccbb.ku.edu.tr/hotregion.

Observation of interface defects in thermally oxidized SiC using positron annihilation

NASA Astrophysics Data System (ADS)

Dekker, James; Saarinen, Kimmo; Ólafsson, Halldór; Sveinbjörnsson, Einar Ö.

2003-03-01

Positron annihilation has been applied to study thermally oxidized 4H- and 6H-SiC. The SiC/SiO2 interface is found to contain a high density of open-volume defects. The positron trapping at the interface defects correlates with the charge of the interface determined by capacitance-voltage experiments. For oxides grown on n-SiC substrates, the positron annihilation characteristics at these defects are nearly indistinguishable from those of a silicon/oxide interface, with no discernable contribution from C-related bonds or carbon clusters. These results indicate that those defects at the SiC/oxide interface, which are visible to positrons, are similar to those at the Si/oxide interface. The positron annihilation characteristics suggest that these defects are vacancies surrounded by oxygen atoms.

SIMPLIFIED LAPAROSCOPIC GASTRIC BYPASS WITH GASTROJEJUNAL LINEAR MECHANICAL ANASTOMOSIS: TECHNICAL ASPECTS.

PubMed

Palermo, Mariano; Serra, Edgardo

Gastric bypass is a restrictive and malabsorptive surgery. The restrictive part consists in the creation of a small gastric pouch. The gastrointestinal bypass serves as the malabsorptive element. To describe a simplified gastric bypass approach for morbid obese patients, showing our results, and also remarking the importance of this technique for reducing the learning curve. The patient is positioned in a split legs position and carefully strapped to the operating room table, with the surgeon between the patient's legs. Five trocars are inserted after pneumoperitoneum at the umbilicus. Dissection of the esophagogastric angle and lesser curvature is mandatory before the gastric pouch manufacturing. This pouch is done with two blue load staplers. Using a blue load linear stapler inserted only half way into the hole in the pouch is used to perform the gastrojejunal anastomosis and in order to create an anastomosis that is about 2 cm in length. A side-to-side jejunojejunostomy is done with a white load linear stapler. The last step of the gastric bypass consists in the cut of the jejunum between the two anastomosis with a white load linear stapler. Blue test is performed in order to detect leaks. From January 2012 to December 2015, 415 simplified RYGB were performed. Gender: 67% female and 33 % males. Average of BMI 44.7. Mean age was 42 years old. Mean operative time 79 min. 39 % of this sample had T2 diabetes. Regarding complications were observed, one fistula, one gastrojejunal stenosis and one obstruction due to a bezoar. The described technique is a simplified approach in which all the anastomosis are performed in the upper part of the abdomen, allowing the surgeons to be more systematized and avoiding them to make mistakes in the confection of the Roux-en-Y anastomosis. This simplified gastric bypass is a safe and reproducible technique. Bypass gástrico é cirurgia restritiva e malabsortiva. A parte restritiva consiste na criação de uma pequena bolsa gástrica. O bypass gastrointestinal serve como o elemento malabsortivo. Descrever uma abordagem de bypass gástrico simplificado para pacientes obesos mórbidos, mostrando os resultados, e também destacando a importância desta técnica para reduzir a curva de aprendizagem. O paciente é posicionado em posição de pernas abertas e cuidadosamente amarrado à mesa da sala de operação com o cirurgião entre as pernas. Cinco trocárteres são inseridos após pneumoperitônio no umbigo. Dissecção do ângulo esofagogástrico e curvatura menor é obrigatória antes da realização da bolsa gástrica. Esta bolsa é feita com dois grampeadores de carga azuis. Usando um grampeador carga linear azul inserido apenas a meio caminho para dentro do orifício na bolsa é executada a anastomose gastrojejunal a fim de criar anastomose de cerca de 2 cm de comprimento. Jejunojejunostomia laretolateral é feita com um grampeador carga linear branca. A última etapa do bypass gástrico consiste no corte do jejuno entre as duas anastomoses com um grampeador carga linear branco. Teste de azul é realizado de modo a detectar vazamentos. De janeiro de 2012 a dezembro de 2015, foram realizadas 415 RYGB simplificadas. Gênero: 67% homens e 33% mulheres. A média do IMC foi de 44,7 e a de idade 42 anos. A média de tempo operatório foi de 79 min. 39% desta amostra tinha diabete melito tipo 2. Quanto às complicações foram observadas uma fístula, uma estenose gastrojejunal e uma obstrução devido à bezoar. A técnica descrita é uma abordagem simplificada, na qual todas as anastomoses são realizadas na parte superior do abdome, permitindo aos cirurgiões serem mais sistematizados e evitando cometerem erros na confecção da anastomose em Y-de-Roux. Este bypass gástrico simplificado é técnica segura e reprodutível.

Factors associated with interest in novel interfaces for upper limb prosthesis control

PubMed Central

Engdahl, Susannah M.; Chestek, Cynthia A.; Kelly, Brian; Davis, Alicia

2017-01-01

Background Surgically invasive interfaces for upper limb prosthesis control may allow users to operate advanced, multi-articulated devices. Given the potential medical risks of these invasive interfaces, it is important to understand what factors influence an individual’s decision to try one. Methods We conducted an anonymous online survey of individuals with upper limb loss. A total of 232 participants provided personal information (such as age, amputation level, etc.) and rated how likely they would be to try noninvasive (myoelectric) and invasive (targeted muscle reinnervation, peripheral nerve interfaces, cortical interfaces) interfaces for prosthesis control. Bivariate relationships between interest in each interface and 16 personal descriptors were examined. Significant variables from the bivariate analyses were then entered into multiple logistic regression models to predict interest in each interface. Results While many of the bivariate relationships were significant, only a few variables remained significant in the regression models. The regression models showed that participants were more likely to be interested in all interfaces if they had unilateral limb loss (p ≤ 0.001, odds ratio ≥ 2.799). Participants were more likely to be interested in the three invasive interfaces if they were younger (p < 0.001, odds ratio ≤ 0.959) and had acquired limb loss (p ≤ 0.012, odds ratio ≥ 3.287). Participants who used a myoelectric device were more likely to be interested in myoelectric control than those who did not (p = 0.003, odds ratio = 24.958). Conclusions Novel prosthesis control interfaces may be accepted most readily by individuals who are young, have unilateral limb loss, and/or have acquired limb loss However, this analysis did not include all possible factors that may have influenced participant’s opinions on the interfaces, so additional exploration is warranted. PMID:28767716

Self-assembly of a surfactin nanolayer at solid-liquid and air-liquid interfaces.

PubMed

Onaizi, Sagheer A; Nasser, M S; Al-Lagtah, Nasir M A

2016-05-01

Surfactin, a sustainable and environmentally friendly surface active agent, is used as a model to study the adsorption of biosurfactants at hydrophobic and hydrophilic solid-liquid interfaces as well as the air-liquid interface. Surfactin adsorption was monitored as a function of time and concentration using surface plasmon resonance (SPR) technique in the case of the solid-liquid interfaces or the drop shape analysis (DSA) technique in the case of the air-liquid interface. The results obtained in this study showed that surfactin adsorption at the "hard" hydrophobic (functionalized with octadecanethiol) solid-liquid and the "soft" air-liquid interface were 1.12 ± 0.01 mg m(-2) (area per molecule of 157 ± 2 Å(2)) and 1.11 ± 0.05 mg m(-2) (area per molecule of 159 ± 7 Å(2)), respectively, demonstrating the negligible effect of the interface "hardness" on surfactin adsorption. The adsorption of surfactin at the hydrophilic (functionalized with β-mercaptoethanol) solid-liquid interface was about threefold lower than its adsorption at the hydrophobic-liquid interfaces, revealing the importance of hydrophobic interaction in surfactin adsorption process. The affinity constant of surfactin for the investigated interfaces follows the following order: air > octadecanethiol > β-mercaptoethanol. Biosurfactants, such as surfactin, are expected to replace the conventional fossil-based surfactants in several applications, and therefore the current study is a contribution towards the fundamental understanding of biosurfactant behavior, on a molecular level, at hydrophobic and hydrophilic solid-liquid interfaces in addition to the air-liquid interface. Such understanding might aid further optimization of the utilization of surfactin in a number of industrial applications such as enhanced oil recovery, bioremediation, and detergency.

Protein denaturants at aqueous-hydrophobic interfaces: self-consistent correlation between induced interfacial fluctuations and denaturant stability at the interface.

PubMed

Cui, Di; Ou, Shu-Ching; Patel, Sandeep

2015-01-08

The notion of direct interaction between denaturing cosolvent and protein residues has been proposed in dialogue relevant to molecular mechanisms of protein denaturation. Here we consider the correlation between free energetic stability and induced fluctuations of an aqueous-hydrophobic interface between a model hydrophobically associating protein, HFBII, and two common protein denaturants, guanidinium cation (Gdm(+)) and urea. We compute potentials of mean force along an order parameter that brings the solute molecule close to the known hydrophobic region of the protein. We assess potentials of mean force for different relative orientations between the protein and denaturant molecule. We find that in both cases of guanidinium cation and urea relative orientations of the denaturant molecule that are parallel to the local protein-water interface exhibit greater stability compared to edge-on or perpendicular orientations. This behavior has been observed for guanidinium/methylguanidinium cations at the liquid-vapor interface of water, and thus the present results further corroborate earlier findings. Further analysis of the induced fluctuations of the aqueous-hydrophobic interface upon approach of the denaturant molecule indicates that the parallel orientation, displaying a greater stability at the interface, also induces larger fluctuations of the interface compared to the perpendicular orientations. The correlation of interfacial stability and induced interface fluctuation is a recurring theme for interface-stable solutes at hydrophobic interfaces. Moreover, observed correlations between interface stability and induced fluctuations recapitulate connections to local hydration structure and patterns around solutes as evidenced by experiment (Cooper et al., J. Phys. Chem. A 2014, 118, 5657.) and high-level ab initio/DFT calculations (Baer et al., Faraday Discuss 2013, 160, 89).

Protein Denaturants at Aqueous–Hydrophobic Interfaces: Self-Consistent Correlation between Induced Interfacial Fluctuations and Denaturant Stability at the Interface

PubMed Central

2015-01-01

The notion of direct interaction between denaturing cosolvent and protein residues has been proposed in dialogue relevant to molecular mechanisms of protein denaturation. Here we consider the correlation between free energetic stability and induced fluctuations of an aqueous–hydrophobic interface between a model hydrophobically associating protein, HFBII, and two common protein denaturants, guanidinium cation (Gdm+) and urea. We compute potentials of mean force along an order parameter that brings the solute molecule close to the known hydrophobic region of the protein. We assess potentials of mean force for different relative orientations between the protein and denaturant molecule. We find that in both cases of guanidinium cation and urea relative orientations of the denaturant molecule that are parallel to the local protein–water interface exhibit greater stability compared to edge-on or perpendicular orientations. This behavior has been observed for guanidinium/methylguanidinium cations at the liquid–vapor interface of water, and thus the present results further corroborate earlier findings. Further analysis of the induced fluctuations of the aqueous–hydrophobic interface upon approach of the denaturant molecule indicates that the parallel orientation, displaying a greater stability at the interface, also induces larger fluctuations of the interface compared to the perpendicular orientations. The correlation of interfacial stability and induced interface fluctuation is a recurring theme for interface-stable solutes at hydrophobic interfaces. Moreover, observed correlations between interface stability and induced fluctuations recapitulate connections to local hydration structure and patterns around solutes as evidenced by experiment (Cooper et al., J. Phys. Chem. A2014, 118, 5657.) and high-level ab initio/DFT calculations (Baer et al., Faraday Discuss2013, 160, 89). PMID:25536388

Controlling the electronic and geometric structures of 2D insertions to realize high performance metal/insertion-MoS2 sandwich interfaces.

PubMed

Su, Jie; Feng, Liping; Zeng, Wei; Liu, Zhengtang

2017-06-08

Metal/insertion-MoS 2 sandwich interfaces are designed to reduce the Schottky barriers at metal-MoS 2 interfaces. The effects of geometric and electronic structures of two-dimensional (2D) insertion materials on the contact properties of metal/insertion-MoS 2 interfaces are comparatively studied by first-principles calculations. Regardless of the geometric and electronic structures of 2D insertion materials, Fermi level pinning effects and charge scattering at the metal/insertion-MoS 2 interface are weakened due to weak interactions between the insertion and MoS 2 layers, no gap states and negligible structural deformations for MoS 2 layers. The Schottky barriers at metal/insertion-MoS 2 interfaces are induced by three interface dipoles and four potential steps that are determined by the charge transfers and structural deformations of 2D insertion materials. The lower the electron affinities of 2D insertion materials, the more are the electrons lost from the Sc surface, resulting in lower n-type Schottky barriers at Sc/insertion-MoS 2 interfaces. The larger the ionization potentials and the thinner the thicknesses of 2D insertion materials, the fewer are the electrons that accumulate at the Pt surface, leading to lower p-type Schottky barriers at Pt/insertion-MoS 2 interfaces. All Sc/insertion-MoS 2 interfaces exhibited ohmic characters. The Pt/BN-MoS 2 interface exhibits the lowest p-type Schottky barrier of 0.52 eV due to the largest ionization potential (∼6.88 eV) and the thinnest thickness (single atomic layer thickness) of BN. These results in this work are beneficial to understand and design high performance metal/insertion-MoS 2 interfaces through 2D insertion materials.

Conversion of spin current into charge current in a topological insulator: Role of the interface

NASA Astrophysics Data System (ADS)

Dey, Rik; Prasad, Nitin; Register, Leonard F.; Banerjee, Sanjay K.

2018-05-01

Three-dimensional spin current density injected onto the surface of a topological insulator (TI) produces a two-dimensional charge current density on the surface of the TI, which is the so-called inverse Edelstein effect (IEE). The ratio of the surface charge current density on the TI to the spin current density injected across the interface defined as the IEE length was shown to be exactly equal to the mean free path in the TI determined to be independent of the electron transmission rate across the interface [Phys. Rev. B 94, 184423 (2016), 10.1103/PhysRevB.94.184423]. However, we find that the transmission rate across the interface gives a nonzero contribution to the transport relaxation rate in the TI as well as to the effective IEE relaxation rate (over and above any surface hybridization effects), and the IEE length is always less than the original mean free path in the TI without the interface. We show that both the IEE relaxation time and the transport relaxation time in the TI are modified by the interface transmission time. The correction becomes significant when the transmission time across the interface becomes comparable to or less than the original momentum scattering time in the TI. This correction is similar to experimental results in Rashba electron systems in which the IEE relaxation time was found shorter in the case of direct interface with metal in which the interface transmission rate will be much higher, compared to interfaces incorporating insulating oxides. Our results indicate the continued importance of the interface to obtain a better spin-to-charge current conversion and a limitation to the conversion efficiency due to the quality of the interface.

Factors associated with interest in novel interfaces for upper limb prosthesis control.

PubMed

Engdahl, Susannah M; Chestek, Cynthia A; Kelly, Brian; Davis, Alicia; Gates, Deanna H

2017-01-01

Surgically invasive interfaces for upper limb prosthesis control may allow users to operate advanced, multi-articulated devices. Given the potential medical risks of these invasive interfaces, it is important to understand what factors influence an individual's decision to try one. We conducted an anonymous online survey of individuals with upper limb loss. A total of 232 participants provided personal information (such as age, amputation level, etc.) and rated how likely they would be to try noninvasive (myoelectric) and invasive (targeted muscle reinnervation, peripheral nerve interfaces, cortical interfaces) interfaces for prosthesis control. Bivariate relationships between interest in each interface and 16 personal descriptors were examined. Significant variables from the bivariate analyses were then entered into multiple logistic regression models to predict interest in each interface. While many of the bivariate relationships were significant, only a few variables remained significant in the regression models. The regression models showed that participants were more likely to be interested in all interfaces if they had unilateral limb loss (p ≤ 0.001, odds ratio ≥ 2.799). Participants were more likely to be interested in the three invasive interfaces if they were younger (p < 0.001, odds ratio ≤ 0.959) and had acquired limb loss (p ≤ 0.012, odds ratio ≥ 3.287). Participants who used a myoelectric device were more likely to be interested in myoelectric control than those who did not (p = 0.003, odds ratio = 24.958). Novel prosthesis control interfaces may be accepted most readily by individuals who are young, have unilateral limb loss, and/or have acquired limb loss However, this analysis did not include all possible factors that may have influenced participant's opinions on the interfaces, so additional exploration is warranted.

Micro-mechanical modeling of the cement-bone interface: the effect of friction, morphology and material properties on the micromechanical response.

PubMed

Janssen, Dennis; Mann, Kenneth A; Verdonschot, Nico

2008-11-14

In order to gain insight into the micro-mechanical behavior of the cement-bone interface, the effect of parametric variations of frictional, morphological and material properties on the mechanical response of the cement-bone interface were analyzed using a finite element approach. Finite element models of a cement-bone interface specimen were created from micro-computed tomography data of a physical specimen that was sectioned from an in vitro cemented total hip arthroplasty. In five models the friction coefficient was varied (mu=0.0; 0.3; 0.7; 1.0 and 3.0), while in one model an ideally bonded interface was assumed. In two models cement interface gaps and an optimal cement penetration were simulated. Finally, the effect of bone cement stiffness variations was simulated (2.0 and 2.5 GPa, relative to the default 3.0 GPa). All models were loaded for a cycle of fully reversible tension-compression. From the simulated stress-displacement curves the interface deformation, stiffness and hysteresis were calculated. The results indicate that in the current model the mechanical properties of the cement-bone interface were caused by frictional phenomena at the shape-closed interlock rather than by adhesive properties of the cement. Our findings furthermore show that in our model maximizing cement penetration improved the micromechanical response of the cement-bone interface stiffness, while interface gaps had a detrimental effect. Relative to the frictional and morphological variations, variations in the cement stiffness had only a modest effect on the micro-mechanical behavior of the cement-bone interface. The current study provides information that may help to better understand the load-transfer mechanisms taking place at the cement-bone interface.

Relaxation, Structure and Properties of Semi-coherent Interfaces

DOE PAGES

Shao, Shuai; Wang, Jian

2015-11-05

Materials containing high density of interfaces are promising candidates for future energy technologies, because interfaces acting as sources, sinks, and barriers for defects can improve mechanical and irradiation properties of materials. Semi-coherent interface widely occurring in various materials is composed of a network of misfit dislocations and coherent regions separated by misfit dislocations. Lastly, in this article, we review relaxation mechanisms, structure and properties of (111) semi-coherent interfaces in face centered cubic structures.

INL Multi-Robot Control Interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

2005-03-30

The INL Multi-Robot Control Interface controls many robots through a single user interface. The interface includes a robot display window for each robot showing the robot’s condition. More than one window can be used depending on the number of robots. The user interface also includes a robot control window configured to receive commands for sending to the respective robot and a multi-robot common window showing information received from each robot.

Design and Implementation of an Interface Editor for the Amadeus Multi- Relational Database Front-end System

DTIC Science & Technology

1993-03-25

application of Object-Oriented Programming (OOP) and Human-Computer Interface (HCI) design principles. Knowledge gained from each topic has been incorporated...through the ap- plication of Object-Oriented Programming (OOP) and Human-Computer Interface (HCI) design principles. Knowledge gained from each topic has...programming and Human-Computer Interface (HCI) design. Knowledge gained from each is applied to the design of a Form-based interface for database data

Interface Technology for Geometrically Nonlinear Analysis of Multiple Connected Subdomains

NASA Technical Reports Server (NTRS)

Ransom, Jonathan B.

1997-01-01

Interface technology for geometrically nonlinear analysis is presented and demonstrated. This technology is based on an interface element which makes use of a hybrid variational formulation to provide for compatibility between independently modeled connected subdomains. The interface element developed herein extends previous work to include geometric nonlinearity and to use standard linear and nonlinear solution procedures. Several benchmark nonlinear applications of the interface technology are presented and aspects of the implementation are discussed.

SWMM5 Application Programming Interface and PySWMM: A Python Interfacing Wrapper

EPA Science Inventory

In support of the OpenWaterAnalytics open source initiative, the PySWMM project encompasses the development of a Python interfacing wrapper to SWMM5 with parallel ongoing development of the USEPA Stormwater Management Model (SWMM5) application programming interface (API). ...

Active oil-water interfaces: buckling and deformation of oil drops by bacteria

NASA Astrophysics Data System (ADS)

Juarez, Gabriel; Stocker, Roman

2014-11-01

Bacteria are unicellular organisms that seek nutrients and energy for growth, division, and self-propulsion. Bacteria are also natural colloidal particles that attach and self-assemble at liquid-liquid interfaces. Here, we present experimental results on active oil-water interfaces that spontaneously form when bacteria accumulate or grow on the interface. Using phase-contrast and fluorescence microscopy, we simultaneously observed the dynamics of adsorbed Alcanivorax bacteria and the oil-water interface within microfluidic devices. We find that, by growing and dividing, adsorbed bacteria form a jammed monolayer of cells that encapsulates the entire oil drop. As bacteria continue to grow at the interface, the drop buckles and the interface undergoes strong deformations. The bacteria act to stabilize non-equilibrium shapes of the oil-phase such wrinkling and tubulation. In addition to presenting a natural example of a living interface, these findings shape our understanding of microbial degradation of oil and may have important repercussions on engineering interventions for oil bioremediation.

Electron confinement at diffuse ZnMgO/ZnO interfaces

NASA Astrophysics Data System (ADS)

Coke, Maddison L.; Kennedy, Oscar W.; Sagar, James T.; Warburton, Paul A.

2017-01-01

Abrupt interfaces between ZnMgO and ZnO are strained due to lattice mismatch. This strain is relaxed if there is a gradual incorporation of Mg during growth, resulting in a diffuse interface. This strain relaxation is however accompanied by reduced confinement and enhanced Mg-ion scattering of the confined electrons at the interface. Here we experimentally study the electronic transport properties of the diffuse heteroepitaxial interface between single-crystal ZnO and ZnMgO films grown by molecular-beam epitaxy. The spatial extent of the interface region is controlled during growth by varying the zinc flux. We show that, as the spatial extent of the graded interface is reduced, the enhancement of electron mobility due to electron confinement more than compensates for any suppression of mobility due to increased strain. Furthermore, we determine the extent to which scattering of impurities in the ZnO substrate limits the electron mobility in diffuse ZnMgO-ZnO interfaces.

Effect of Various Interface Thicknesses on the Behaviour of Infilled frame Subjected to Lateral Load

NASA Astrophysics Data System (ADS)

Senthil, K.; Muthukumar, S.; Rupali, S.; Satyanarayanan, K. S.

2018-03-01

Two dimensional numerical investigations were carried out to study the influence of interface thickness on the behaviour of reinforced concrete frames subjected to in-plane lateral loads using commercial finite element tool SAP 2000. The cement mortar, cork and foam was used as interface material and their effect was studied by varying thicknesses as 6, 8, 10, 14 and 20 mm. The effect of lateral loads on infill masonry wall was also studied by varying arbitrary loads as 10, 20, 40 and 60 kN. The resistance of the frame with cement mortar was found maximum with the interface thickness 10 mm therefore, it is concluded that the maximum influence of interface thickness of 10 mm was found effective. The resistance of integral infill frame with cork and foam interface was found maximum with the interface thickness 6 mm and it is concluded that 6 mm thick interface among the chosen thickness was found effective.

Distributed user interfaces for clinical ubiquitous computing applications.

PubMed

Bång, Magnus; Larsson, Anders; Berglund, Erik; Eriksson, Henrik

2005-08-01

Ubiquitous computing with multiple interaction devices requires new interface models that support user-specific modifications to applications and facilitate the fast development of active workspaces. We have developed NOSTOS, a computer-augmented work environment for clinical personnel to explore new user interface paradigms for ubiquitous computing. NOSTOS uses several devices such as digital pens, an active desk, and walk-up displays that allow the system to track documents and activities in the workplace. We present the distributed user interface (DUI) model that allows standalone applications to distribute their user interface components to several devices dynamically at run-time. This mechanism permit clinicians to develop their own user interfaces and forms to clinical information systems to match their specific needs. We discuss the underlying technical concepts of DUIs and show how service discovery, component distribution, events and layout management are dealt with in the NOSTOS system. Our results suggest that DUIs--and similar network-based user interfaces--will be a prerequisite of future mobile user interfaces and essential to develop clinical multi-device environments.

Gas-liquid interface of room-temperature ionic liquids.

PubMed

Santos, Cherry S; Baldelli, Steven

2010-06-01

The organization of ions at the interface of ionic liquids and the vacuum is an ideal system to test new ideas and concepts on the interfacial chemistry of electrolyte systems in the limit of no solvent medium. Whilst electrolyte systems have numerous theoretical and experimental methods used to investigate their properties, the ionic liquids are relatively new and our understanding of the interfacial properties is just beginning to be explored. In this critical review, the gas-liquid interface is reviewed, as this interface does not depend on the preparation of another medium and thus produces a natural interface. The interface has been investigated by sum frequency generation vibrational spectroscopy and ultra-high vacuum techniques. The results provide a detailed molecular-level view of the surface composition and structure. These have been complemented by theoretical studies. The combinations of treatments on this interface are starting to provide a somewhat convergent description of how the ions are organized at this neat interface (108 references).

Diffuse-interface model for rapid phase transformations in nonequilibrium systems.

PubMed

Galenko, Peter; Jou, David

2005-04-01

A thermodynamic approach to rapid phase transformations within a diffuse interface in a binary system is developed. Assuming an extended set of independent thermodynamic variables formed by the union of the classic set of slow variables and the space of fast variables, we introduce finiteness of the heat and solute diffusive propagation at the finite speed of the interface advancing. To describe transformations within the diffuse interface, we use the phase-field model which allows us to follow steep but smooth changes of phase within the width of the diffuse interface. Governing equations of the phase-field model are derived for the hyperbolic model, a model with memory, and a model of nonlinear evolution of transformation within the diffuse interface. The consistency of the model is proved by the verification of the validity of the condition of positive entropy production and by outcomes of the fluctuation-dissipation theorem. A comparison with existing sharp-interface and diffuse-interface versions of the model is given.

[A study on the bond interface between low-fusing dental porcelain and pure titanium].

PubMed

Mo, A; Cen, Y; Liao, Y; Wang, J; Shi, X

2001-09-01

To evaluate the bond interface between low fusing dental porcelain and pure titanium by observing the topography and detecting the ionic diffusion in the interface area. The low fusing-porcelain La-porcelain produced by the authors or Vita Titankeramik porcelain was fused to the surfaces of pure titanium. The topography of the interface between pure titanium and porcelain, and the structure of experimental materials were observed with SEM. The state of ionic diffusion in the interface area was investigated with EPMA. Excellent permeation and diffusion of La-porcelain were observed on the surfaces of pure titanium. The diffusion of ions of stannum and silicon was discovered in the interface area. The microstructure of La-porcelain to pure titanium bond interface was finer than that of Vita Titankeramik porcelain. Excellent bond can be produced in the interface between La-porcelain and pure titanium. The bonding mechanism may involve mechanical bond and chemical bond. The ionic diffusion of stannum plays an important role in the bonding of porcelain to pure titanium.

Non-random walk diffusion enhances the sink strength of semicoherent interfaces

DOE PAGES

Vattré, A.; Jourdan, T.; Ding, H.; ...

2016-01-29

Clean, safe and economical nuclear energy requires new materials capable of withstanding severe radiation damage. One strategy of imparting radiation resistance to solids is to incorporate into them a high density of solid-phase interfaces capable of absorbing and annihilating radiation-induced defects. Here we show that elastic interactions between point defects and semicoherent interfaces lead to a marked enhancement in interface sink strength. Our conclusions stem from simulations that integrate first principles, object kinetic Monte Carlo and anisotropic elasticity calculations. Surprisingly, the enhancement in sink strength is not due primarily to increased thermodynamic driving forces, but rather to reduced defect migrationmore » barriers, which induce a preferential drift of defects towards interfaces. The sink strength enhancement is highly sensitive to the detailed character of interfacial stresses, suggesting that ‘super-sink’ interfaces may be designed by optimizing interface stress fields. Lastly, such interfaces may be used to create materials with unprecedented resistance to radiation-induced damage.« less

Comfort evaluation of a subject-specific seating interface formed by vibrating grains.

PubMed

Liu, Shenghui; Qu, Yunxia; Hou, Shujun; Li, Kai; Li, Xinye; Zhai, Yang; Ji, Yunxiao

2018-09-01

Sitting is the most common posture for work in offices, and spinal cord injury (SCI) patients who are wheelchair dependent spend 10.6 h per day seated in wheelchairs. Thus, the comfort of subject-specific interfaces is increasingly important for the well-being of patients and office workers. This paper introduces a new method of forming a subject-specific interface, based on vibrating grains. Twenty subjects (10 females and 10 males) participated in the sitting test. Interface comfort was evaluated using the pressure distribution and subjective rating methods. Five seating interface types were compared. The results showed that compared with a flat interface, the interfaces formed by vibrating grains had a significantly reduced peak contact pressure (PeakCP) (by more than 58.03%), and that PeakCP was highly correlated with the comfort rating (R = -0.533) and discomfort rating(R = -0.603). This new method shows promise for guiding the future development of customized seating interfaces. Copyright © 2018 Elsevier Ltd. All rights reserved.

On the Ionization and Ion Transmission Efficiencies of Different ESI-MS Interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, Jonathan T.; Marginean, Ioan; Smith, Richard D.

2014-09-30

It is well known that the achievable sensitivity of electrospray ionization mass spectrometry (ESI-MS) is largely determined by the ionization efficiency in the ESI source and ion transmission efficiency through the ESI-MS interface. In this report we systematically study the ion transmission and ionization efficiencies in different ESI-MS interface configurations. The configurations under investigation include a single emitter/single inlet capillary, single emitter/multi-inlet capillary, and a subambient pressure ionization with nanoelectrospray (SPIN) MS interfaces with a single emitter and an emitter array, respectively. We present an effective method to evaluate the overall ion utilization efficiency of an ESI-MS interface by measuringmore » the total gas phase ion current transmitted through the interface and correlating it to the observed ion abundance measured in the corresponding mass spectrum. Our experimental results suggest that the overall ion utilization efficiency in the SPIN-MS interface configurations is better than that in the inlet capillary based ESI-MS interface configurations.« less

Transient Dupuit Interface Flow with partially penetrating features

NASA Astrophysics Data System (ADS)

Bakker, Mark

1998-11-01

A comprehensive potential is presented for Dupuit interface flow in coastal aquifers where both the fresh water and salt water are moving. The resulting potential flow problem may be solved, for incompressible confined aquifers, using analytic functions. The vertical velocity of the interface may then be computed analytically and the change of the position of the interface may be simulated by numerical integration through time, starting with a known (or estimated) initial position. The upconing of the interface below a partially penetrating ditch or well may be studied if Dupuit solutions for such features are available. A new Dupuit solution is derived for a ditch that penetrates the aquifer partially from above; a Dupuit solution for a partially penetrating well may be obtained following a similar derivation. The new Dupuit solution is combined with the interface solution to simulate the upconing of an initially horizontal interface below a series of partially penetrating ditches; the interface converges to the known steady state position.

Nanoparticle Assemblies at Fluid Interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, Thomas P.

2015-03-10

A systematic study of the structure and dynamics of nanoparticles (NP) and NP-surfactants was performed. The ligands attached to both the NPs and NP-surfactants dictate the manner in which the nanoscopic materials assemble at fluid interfaces. Studies have shown that a single layer of the nanoscpic materials form at the interface to reduce the interactions between the two immiscible fluids. The shape of the NP is, also, important, where for spherical particles, a disordered, liquid-like monolayer forms, and, for nanorods, ordered domains at the interface is found and, if the monolayers are compressed, the orientation of the nanorods with respectmore » to the interface can change. By associating end-functionalized polymers to the NPs assembled at the interface, NP-surfactants are formed that increase the energetic gain in segregating each NP at the interface which allows the NP-surfactants to jam at the interface when compressed. This has opened the possibility of structuring the two liquids by freezing in shape changes of the liquids.« less

Self-diffusion Coefficient and Structure of Binary n-Alkane Mixtures at the Liquid-Vapor Interfaces.

PubMed

Chilukoti, Hari Krishna; Kikugawa, Gota; Ohara, Taku

2015-10-15

The self-diffusion coefficient and molecular-scale structure of several binary n-alkane liquid mixtures in the liquid-vapor interface regions have been examined using molecular dynamics simulations. It was observed that in hexane-tetracosane mixture hexane molecules are accumulated in the liquid-vapor interface region and the accumulation intensity decreases with increase in a molar fraction of hexane in the examined range. Molecular alignment and configuration in the interface region of the liquid mixture change with a molar fraction of hexane. The self-diffusion coefficient in the direction parallel to the interface of both tetracosane and hexane in their binary mixture increases in the interface region. It was found that the self-diffusion coefficient of both tetracosane and hexane in their binary mixture is considerably higher in the vapor side of the interface region as the molar fraction of hexane goes lower, which is mostly due to the increase in local free volume caused by the local structure of the liquid in the interface region.

Rapid Prototyping of Hydrologic Model Interfaces with IPython

NASA Astrophysics Data System (ADS)

Farthing, M. W.; Winters, K. D.; Ahmadia, A. J.; Hesser, T.; Howington, S. E.; Johnson, B. D.; Tate, J.; Kees, C. E.

2014-12-01

A significant gulf still exists between the state of practice and state of the art in hydrologic modeling. Part of this gulf is due to the lack of adequate pre- and post-processing tools for newly developed computational models. The development of user interfaces has traditionally lagged several years behind the development of a particular computational model or suite of models. As a result, models with mature interfaces often lack key advancements in model formulation, solution methods, and/or software design and technology. Part of the problem has been a focus on developing monolithic tools to provide comprehensive interfaces for the entire suite of model capabilities. Such efforts require expertise in software libraries and frameworks for creating user interfaces (e.g., Tcl/Tk, Qt, and MFC). These tools are complex and require significant investment in project resources (time and/or money) to use. Moreover, providing the required features for the entire range of possible applications and analyses creates a cumbersome interface. For a particular site or application, the modeling requirements may be simplified or at least narrowed, which can greatly reduce the number and complexity of options that need to be accessible to the user. However, monolithic tools usually are not adept at dynamically exposing specific workflows. Our approach is to deliver highly tailored interfaces to users. These interfaces may be site and/or process specific. As a result, we end up with many, customized interfaces rather than a single, general-use tool. For this approach to be successful, it must be efficient to create these tailored interfaces. We need technology for creating quality user interfaces that is accessible and has a low barrier for integration into model development efforts. Here, we present efforts to leverage IPython notebooks as tools for rapid prototyping of site and application-specific user interfaces. We provide specific examples from applications in near-shore environments as well as levee analysis. We discuss our design decisions and methodology for developing customized interfaces, strategies for delivery of the interfaces to users in various computing environments, as well as implications for the design/implementation of simulation models.

A PDB-wide, evolution-based assessment of protein-protein interfaces.

PubMed

Baskaran, Kumaran; Duarte, Jose M; Biyani, Nikhil; Bliven, Spencer; Capitani, Guido

2014-10-18

Thanks to the growth in sequence and structure databases, more than 50 million sequences are now available in UniProt and 100,000 structures in the PDB. Rich information about protein-protein interfaces can be obtained by a comprehensive study of protein contacts in the PDB, their sequence conservation and geometric features. An automated computational pipeline was developed to run our Evolutionary Protein-Protein Interface Classifier (EPPIC) software on the entire PDB and store the results in a relational database, currently containing > 800,000 interfaces. This allows the analysis of interface data on a PDB-wide scale. Two large benchmark datasets of biological interfaces and crystal contacts, each containing about 3000 entries, were automatically generated based on criteria thought to be strong indicators of interface type. The BioMany set of biological interfaces includes NMR dimers solved as crystal structures and interfaces that are preserved across diverse crystal forms, as catalogued by the Protein Common Interface Database (ProtCID) from Xu and Dunbrack. The second dataset, XtalMany, is derived from interfaces that would lead to infinite assemblies and are therefore crystal contacts. BioMany and XtalMany were used to benchmark the EPPIC approach. The performance of EPPIC was also compared to classifications from the Protein Interfaces, Surfaces, and Assemblies (PISA) program on a PDB-wide scale, finding that the two approaches give the same call in about 88% of PDB interfaces. By comparing our safest predictions to the PDB author annotations, we provide a lower-bound estimate of the error rate of biological unit annotations in the PDB. Additionally, we developed a PyMOL plugin for direct download and easy visualization of EPPIC interfaces for any PDB entry. Both the datasets and the PyMOL plugin are available at http://www.eppic-web.org/ewui/\\#downloads. Our computational pipeline allows us to analyze protein-protein contacts and their sequence conservation across the entire PDB. Two new benchmark datasets are provided, which are over an order of magnitude larger than existing manually curated ones. These tools enable the comprehensive study of several aspects of protein-protein contacts in the PDB and represent a basis for future, even larger scale studies of protein-protein interactions.

Shock interaction with a two-gas interface in a novel dual-driver shock tube

NASA Astrophysics Data System (ADS)

Labenski, John R.

Fluid instabilities exist at the interface between two fluids having different densities if the flow velocity and density gradient are anti-parallel or if a shock wave crosses the boundary. The former case is called the Rayleigh-Taylor (R-T) instability and the latter, the Richtmyer-Meshkov (R-M) instability. Small initial perturbations on the interface destabilize and grow into larger amplitude structures leading to turbulent mixing. Instabilities of this type are seen in inertial confinement fusion (ICF) experiments, laser produced plasmas, supernova explosions, and detonations. A novel dual-driver shock tube was used to investigate the growth rate of the R-M instability. One driver is used to create an argon-refrigerant interface, and the other at the opposite end of the driven section generates a shock to force the interface with compressible flows behind the shock. The refrigerant gas in the first driver is seeded with sub-micron oil droplets for visualization of the interface. The interface travels down the driven section past the test section for a fixed amount of time. A stronger shock of Mach 1.1 to 1.3 drives the interface back past the test section where flow diagnostics are positioned. Two schlieren systems record the density fluctuations while light scattering detectors record the density of the refrigerant as a function of position over the interface. A pair of digital cameras take stereo images of the interface, as mapped out by the tracer particles under illumination by a Q-switched ruby laser. The amount of time that the interface is allowed to travel up the driven section determines the interaction time as a control. Comparisons made between the schlieren signals, light scattering detector outputs, and the images quantify the fingered characteristics of the interface and its growth due to shock forcing. The results show that the interface has a distribution of thickness and that the interaction with a shock further broadens the interface. The growth rate was found to exhibit a dependence on the shock strength.

Learning of Unknown Environments in Goal-Directed Guidance and Navigation Tasks: Autonomous Systems and Humans

NASA Astrophysics Data System (ADS)

Vidal, Joao Vasco Silvestres

Este trabalho expoe um estudo teorico e experimental das propriedades anisotropicas magnetoeletricas (ME) em diferentes compositos contendo monocristais piezoeletricos (PE), maioritariamente sem chumbo na sua composicao, com vista a diversas aplicacoes multifuncionais. Uma descricao linear do efeito ME em termos de campos eletricos, magneticos e elasticos e constantes materiais e apresentada. Um modelo fenomenologico quasi-estatico e usado para ilustrar a relacao entre as constantes materiais, sua anisotropia e os coeficientes MEs transversais de tensao e carga. Subsequentemente, este modelo e empregue para estimar o maximo coeficiente ME direto de tensao expectavel numa serie de compositos tri-camadas de Metglas/Piezocristal/Metglas em funcao da orientacao do cristal PE. Demonstra-se assim como os efeitos MEs sao fortemente dependentes da orientacao cristalina, o que suporta a possibilidade de se gerarem coeficientes MEs de tensao elevados em compositos contendo monocristais PEs sem chumbo como o niobato de litio (LiNbO3; LNO), tantalato de litio (LiTaO3), ortofosfato de galio (GaPO4; GPO), quartzo (SiO2), langatato (La3Ga5.5Ta0.5O14) e langasite (La3Ga5SiO14) atraves da otimizacao da orientacao cristalina. Uma tecnica experimental dinâmica de lock-in para a medicao da impedância e efeito ME direto e exposta. O formalismo descritivo desta tecnica, assim como um arranjo experimental desenvolvido para o efeito sao apresentados. O esquema e caracteristicas deste, assim como diferentes formas de reduzir o ruido e a indesejavel inducao mutua sao exploradas. Um estudo comparativo do efeito ME direto em compositos tri-camadas de Metglas e monocristais de LNO e PMN-PT conectados de forma simples e exposto. Embora o PMN-PT possua piezocoeficientes de carga muito superiores aos do LNO, o coeficiente ME direto de tensao demonstrou-se comparavel entre ambos os compositos devido a uma muito menor permitividade dieletrica do LNO. Calculos teoricos indicam ainda que as propriedades MEs poderao ser significativamente melhoradas (ate 500 V/(cm.Oe)) atraves da otimizacao do ângulo de corte do LNO, espessura relativa entre camadas ferroeletrica/ferromagnetica e uma melhor colagem entre o Metglas e o LNO. Vantagens da utilizacao do material ferroeletrico LNO em compositos MEs sao discutidas. Num estudo subsequente, as propriedades dinâmicas anisotropicas de impedância e MEs em compositos tri-camadas de Metglas e monocristais PEs sem chumbo de LNO e GPO sao exploradas. Medicoes foram realizadas em funcao do corte de cristal, magnitude e orientacao do campo magnetico de polarizacao e frequencia do campo de modulacao. Coeficientes MEs altamente intensos em certos modos de ressonância sao explorados, e a sua relacao com as propriedades materiais dos cristais e geometria dos compositos e investigada. Um coeficiente ME de ate 249 V/(cm.Oe) foi aqui observado num composito com um cristal de LNO com corte 41ºY a 323.1 kHz. Mostramos assim que compositos multicamadas contendo cristais sem chumbo de LNO e GPO podem exibir efeitos MEs anisotropicos relativamente elevados. Demonstramos tambem que o controlo da orientacao dos cristais PEs pode em principio ser usado na obtencao de propriedades MEs anisotropicas desejaveis para qualquer aplicacao. Caracteristicas unicas como elevada estabilidade quimica, piezoeletricidade linear e robusteza termica abrem verdadeiras perspetivas para a utilizacao de compositos baseados no LNO e GPO em diversas aplicacoes. Eventualmente, compositos bi-camadas contendo lâminas PEs com bidominios de LNO com corte 127ºY foram estudados tanto teoricamente como experimentalmente. Estas lâminas de LNO possuem uma estrutura de bidominios com vetores de polarizacao espontânea opostos ao longo da direcao da sua espessura (i.e. uma estrutura de macrodominios ferroeletricos "head-to-head" ou "tail-to-tail") Medicoes de impedância, efeito ME e densidade de ruido magnetico equivalente foram realizadas nos compositos operando sob condicoes quasi-estaticas e de ressonância. Coeficientes MEs de ate 578 V/(cm.Oe) foram obtidos a ca. 30 kHz sob ressonâncias de dobramento usando cristais PEs com 0.5 mm de espessura. Medicoes de densidade de ruido magnetico equivalente demosntraram valores de ate 153 pT/Hz1/2 a 1 kHz (modo quasi-estatico) e 524 fT/Hz1/2 sob condicoes de ressonância. E de esperar que uma otimizacao adicional das tecnicas de fabrico, geometria dos compositos e circuitos de detencao possa permitir reduzir estes valores ate pelo menos 10 pT/Hz1/2 e 250 fT/Hz1/2, respetivamente, e a frequencia de ressonância em pelo menos duas ordens de grandeza. Estes sistemas poderao assim no futuro ser usados em sensores vetoriais de campo magnetico simples e sensiveis, passivos e estaveis e operaveis a elevadas temperaturas. None

Adaptation of the Camera Link Interface for Flight-Instrument Applications

NASA Technical Reports Server (NTRS)

Randall, David P.; Mahoney, John C.

2010-01-01

COTS (commercial-off-the-shelf) hard ware using an industry-standard Camera Link interface is proposed to accomplish the task of designing, building, assembling, and testing electronics for an airborne spectrometer that would be low-cost, but sustain the required data speed and volume. The focal plane electronics were designed to support that hardware standard. Analysis was done to determine how these COTS electronics could be interfaced with space-qualified camera electronics. Interfaces available for spaceflight application do not support the industry standard Camera Link interface, but with careful design, COTS EGSE (electronics ground support equipment), including camera interfaces and camera simulators, can still be used.

Apparatus and method to reduce wear and friction between CMC-to-metal attachment and interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cairo, Ronald Ralph; Parolini, Jason Robert; Delvaux, John McConnell

An apparatus to reduce wear and friction between CMC-to-metal attachment and interface, including a metal layer configured for insertion between a surface interface between a CMC component and a metal component. The surface interface of the metal layer is compliant relative to asperities of the surface interface of the CMC component. A coefficient of friction between the surface interface of the CMC component and the metal component is about 1.0 or less at an operating temperature between about 300.degree. C. to about 325.degree. C. and a limiting temperature of the metal component.

Interfacial Micromechanics in Fibrous Composites: Design, Evaluation, and Models

PubMed Central

Lei, Zhenkun; Li, Xuan; Qin, Fuyong; Qiu, Wei

2014-01-01

Recent advances of interfacial micromechanics in fiber reinforced composites using micro-Raman spectroscopy are given. The faced mechanical problems for interface design in fibrous composites are elaborated from three optimization ways: material, interface, and computation. Some reasons are depicted that the interfacial evaluation methods are difficult to guarantee the integrity, repeatability, and consistency. Micro-Raman study on the fiber interface failure behavior and the main interface mechanical problems in fibrous composites are summarized, including interfacial stress transfer, strength criterion of interface debonding and failure, fiber bridging, frictional slip, slip transition, and friction reloading. The theoretical models of above interface mechanical problems are given. PMID:24977189

Non destructive examination of interface of molecular assembly

NASA Astrophysics Data System (ADS)

Perez, Guy; Richard, Isaline; Lecomte, Jean-Claude

2017-11-01

Molecular assembly interfaces can be characterised by mechanical testing and/or the interaction between waves and the interface. The disadvantage of the mechanical approach is that new defects may be produced at the interface, or existing defects may be destroyed. Using the interaction between waves and the interface is a non-destructive approach. But what kind of waves should be used? Electromagnetic waves in the visible range depend on wave attenuation in the material, infrared waves also depend on the thickness and X-ray waves have a too short a wave length to detect interface defects. In this article, the use of acoustic waves is proposed for non-destructive examination of molecular assembly interfaces. Acoustic wave propagation is very sensitive to variations in interface characteristics depending on whether the waves are reflected or transmitted. To improve the sensitivity and resolution of this technique, small wave lengths have been used with a scanning acoustic microscope (S.A.M.) with a band width from 1MHz to 400 MHz. After a short description of the principle of the method, results are given for different types of components. Different applications of acoustic microscopy are proposed for non-destructive examination of interfaces and defect detection in materials.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

Adaptive multimodal interaction in mobile augmented reality: A conceptual framework

NASA Astrophysics Data System (ADS)

Abidin, Rimaniza Zainal; Arshad, Haslina; Shukri, Saidatul A'isyah Ahmad

2017-10-01

Recently, Augmented Reality (AR) is an emerging technology in many mobile applications. Mobile AR was defined as a medium for displaying information merged with the real world environment mapped with augmented reality surrounding in a single view. There are four main types of mobile augmented reality interfaces and one of them are multimodal interfaces. Multimodal interface processes two or more combined user input modes (such as speech, pen, touch, manual gesture, gaze, and head and body movements) in a coordinated manner with multimedia system output. In multimodal interface, many frameworks have been proposed to guide the designer to develop a multimodal applications including in augmented reality environment but there has been little work reviewing the framework of adaptive multimodal interface in mobile augmented reality. The main goal of this study is to propose a conceptual framework to illustrate the adaptive multimodal interface in mobile augmented reality. We reviewed several frameworks that have been proposed in the field of multimodal interfaces, adaptive interface and augmented reality. We analyzed the components in the previous frameworks and measure which can be applied in mobile devices. Our framework can be used as a guide for designers and developer to develop a mobile AR application with an adaptive multimodal interfaces.

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

DOE PAGES

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

2014-03-27

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

Weak conservation of structural features in the interfaces of homologous transient protein–protein complexes

PubMed Central

Sudha, Govindarajan; Singh, Prashant; Swapna, Lakshmipuram S; Srinivasan, Narayanaswamy

2015-01-01

Residue types at the interface of protein–protein complexes (PPCs) are known to be reasonably well conserved. However, we show, using a dataset of known 3-D structures of homologous transient PPCs, that the 3-D location of interfacial residues and their interaction patterns are only moderately and poorly conserved, respectively. Another surprising observation is that a residue at the interface that is conserved is not necessarily in the interface in the homolog. Such differences in homologous complexes are manifested by substitution of the residues that are spatially proximal to the conserved residue and structural differences at the interfaces as well as differences in spatial orientations of the interacting proteins. Conservation of interface location and the interaction pattern at the core of the interfaces is higher than at the periphery of the interface patch. Extents of variability of various structural features reported here for homologous transient PPCs are higher than the variation in homologous permanent homomers. Our findings suggest that straightforward extrapolation of interfacial nature and inter-residue interaction patterns from template to target could lead to serious errors in the modeled complex structure. Understanding the evolution of interfaces provides insights to improve comparative modeling of PPC structures. PMID:26311309

Spatial Competition: Roughening of an Experimental Interface.

PubMed

Allstadt, Andrew J; Newman, Jonathan A; Walter, Jonathan A; Korniss, G; Caraco, Thomas

2016-07-28

Limited dispersal distance generates spatial aggregation. Intraspecific interactions are then concentrated within clusters, and between-species interactions occur near cluster boundaries. Spread of a locally dispersing invader can become motion of an interface between the invading and resident species, and spatial competition will produce variation in the extent of invasive advance along the interface. Kinetic roughening theory offers a framework for quantifying the development of these fluctuations, which may structure the interface as a self-affine fractal, and so induce a series of temporal and spatial scaling relationships. For most clonal plants, advance should become spatially correlated along the interface, and width of the interface (where invader and resident compete directly) should increase as a power function of time. Once roughening equilibrates, interface width and the relative location of the most advanced invader should each scale with interface length. We tested these predictions by letting white clover (Trifolium repens) invade ryegrass (Lolium perenne). The spatial correlation of clover growth developed as anticipated by kinetic roughening theory, and both interface width and the most advanced invader's lead scaled with front length. However, the scaling exponents differed from those predicted by recent simulation studies, likely due to clover's growth morphology.

Spatial Competition: Roughening of an Experimental Interface

PubMed Central

Allstadt, Andrew J.; Newman, Jonathan A.; Walter, Jonathan A.; Korniss, G.; Caraco, Thomas

2016-01-01

Limited dispersal distance generates spatial aggregation. Intraspecific interactions are then concentrated within clusters, and between-species interactions occur near cluster boundaries. Spread of a locally dispersing invader can become motion of an interface between the invading and resident species, and spatial competition will produce variation in the extent of invasive advance along the interface. Kinetic roughening theory offers a framework for quantifying the development of these fluctuations, which may structure the interface as a self-affine fractal, and so induce a series of temporal and spatial scaling relationships. For most clonal plants, advance should become spatially correlated along the interface, and width of the interface (where invader and resident compete directly) should increase as a power function of time. Once roughening equilibrates, interface width and the relative location of the most advanced invader should each scale with interface length. We tested these predictions by letting white clover (Trifolium repens) invade ryegrass (Lolium perenne). The spatial correlation of clover growth developed as anticipated by kinetic roughening theory, and both interface width and the most advanced invader’s lead scaled with front length. However, the scaling exponents differed from those predicted by recent simulation studies, likely due to clover’s growth morphology. PMID:27465518

Surface and interface sciences of Li-ion batteries. -Research progress in electrode-electrolyte interface-

NASA Astrophysics Data System (ADS)

Minato, Taketoshi; Abe, Takeshi

2017-12-01

The application potential of Li-ion batteries is growing as demand increases in different fields at various stages in energy systems, in addition to their conventional role as power sources for portable devices. In particular, applications in electric vehicles and renewable energy storage are increasing for Li-ion batteries. For these applications, improvements in battery performance are necessary. The Li-ion battery produces and stores electric power from the electrochemical redox reactions between the electrode materials. The interface between the electrodes and electrolyte strongly affects the battery performance because the charge transfer causing the electrode redox reaction begins at this interface. Understanding of the surface structure, electronic structure, and chemical reactions at the electrode-electrolyte interface is necessary to improve battery performance. However, the interface is located between the electrode and electrolyte materials, hindering the experimental analysis of the interface; thus, the physical properties and chemical processes have remained poorly understood until recently. Investigations of the physical properties and chemical processes at the interface have been performed using advanced surface science techniques. In this review, current knowledge and future research prospects regarding the electrode-electrolyte interface are described for the further development of Li-ion batteries.

Design considerations to improve cognitive ergonomic issues of unmanned vehicle interfaces utilizing video game controllers.

PubMed

Oppold, P; Rupp, M; Mouloua, M; Hancock, P A; Martin, J

2012-01-01

Unmanned (UAVs, UCAVs, and UGVs) systems still have major human factors and ergonomic challenges related to the effective design of their control interface systems, crucial to their efficient operation, maintenance, and safety. Unmanned system interfaces with a human centered approach promote intuitive interfaces that are easier to learn, and reduce human errors and other cognitive ergonomic issues with interface design. Automation has shifted workload from physical to cognitive, thus control interfaces for unmanned systems need to reduce mental workload on the operators and facilitate the interaction between vehicle and operator. Two-handed video game controllers provide wide usability within the overall population, prior exposure for new operators, and a variety of interface complexity levels to match the complexity level of the task and reduce cognitive load. This paper categorizes and provides taxonomy for 121 haptic interfaces from the entertainment industry that can be utilized as control interfaces for unmanned systems. Five categories of controllers were based on the complexity of the buttons, control pads, joysticks, and switches on the controller. This allows the selection of the level of complexity needed for a specific task without creating an entirely new design or utilizing an overly complex design.

Electrochemical impedance spectroscopy for quantitative interface state characterization of planar and nanostructured semiconductor-dielectric interfaces

NASA Astrophysics Data System (ADS)

Meng, Andrew C.; Tang, Kechao; Braun, Michael R.; Zhang, Liangliang; McIntyre, Paul C.

2017-10-01

The performance of nanostructured semiconductors is frequently limited by interface defects that trap electronic carriers. In particular, high aspect ratio geometries dramatically increase the difficulty of using typical solid-state electrical measurements (multifrequency capacitance- and conductance-voltage testing) to quantify interface trap densities (D it). We report on electrochemical impedance spectroscopy (EIS) to characterize the energy distribution of interface traps at metal oxide/semiconductor interfaces. This method takes advantage of liquid electrolytes, which provide conformal electrical contacts. Planar Al2O3/p-Si and Al2O3/p-Si0.55Ge0.45 interfaces are used to benchmark the EIS data against results obtained from standard electrical testing methods. We find that the solid state and EIS data agree very well, leading to the extraction of consistent D it energy distributions. Measurements carried out on pyramid-nanostructured p-Si obtained by KOH etching followed by deposition of a 10 nm ALD-Al2O3 demonstrate the application of EIS to trap characterization of a nanostructured dielectric/semiconductor interface. These results show the promise of this methodology to measure interface state densities for a broad range of semiconductor nanostructures such as nanowires, nanofins, and porous structures.

Improvement of design of a surgical interface using an eye tracking device

PubMed Central

2014-01-01

Background Surgical interfaces are used for helping surgeons in interpretation and quantification of the patient information, and for the presentation of an integrated workflow where all available data are combined to enable optimal treatments. Human factors research provides a systematic approach to design user interfaces with safety, accuracy, satisfaction and comfort. One of the human factors research called user-centered design approach is used to develop a surgical interface for kidney tumor cryoablation. An eye tracking device is used to obtain the best configuration of the developed surgical interface. Methods Surgical interface for kidney tumor cryoablation has been developed considering the four phases of user-centered design approach, which are analysis, design, implementation and deployment. Possible configurations of the surgical interface, which comprise various combinations of menu-based command controls, visual display of multi-modal medical images, 2D and 3D models of the surgical environment, graphical or tabulated information, visual alerts, etc., has been developed. Experiments of a simulated cryoablation of a tumor task have been performed with surgeons to evaluate the proposed surgical interface. Fixation durations and number of fixations at informative regions of the surgical interface have been analyzed, and these data are used to modify the surgical interface. Results Eye movement data has shown that participants concentrated their attention on informative regions more when the number of displayed Computer Tomography (CT) images has been reduced. Additionally, the time required to complete the kidney tumor cryoablation task by the participants had been decreased with the reduced number of CT images. Furthermore, the fixation durations obtained after the revision of the surgical interface are very close to what is observed in visual search and natural scene perception studies suggesting more efficient and comfortable interaction with the surgical interface. The National Aeronautics and Space Administration Task Load Index (NASA-TLX) and Short Post-Assessment Situational Awareness (SPASA) questionnaire results have shown that overall mental workload of surgeons related with surgical interface has been low as it has been aimed, and overall situational awareness scores of surgeons have been considerably high. Conclusions This preliminary study highlights the improvement of a developed surgical interface using eye tracking technology to obtain the best SI configuration. The results presented here reveal that visual surgical interface design prepared according to eye movement characteristics may lead to improved usability. PMID:25080176

Improvement of design of a surgical interface using an eye tracking device.

PubMed

Erol Barkana, Duygun; Açık, Alper; Duru, Dilek Goksel; Duru, Adil Deniz

2014-05-07

Surgical interfaces are used for helping surgeons in interpretation and quantification of the patient information, and for the presentation of an integrated workflow where all available data are combined to enable optimal treatments. Human factors research provides a systematic approach to design user interfaces with safety, accuracy, satisfaction and comfort. One of the human factors research called user-centered design approach is used to develop a surgical interface for kidney tumor cryoablation. An eye tracking device is used to obtain the best configuration of the developed surgical interface. Surgical interface for kidney tumor cryoablation has been developed considering the four phases of user-centered design approach, which are analysis, design, implementation and deployment. Possible configurations of the surgical interface, which comprise various combinations of menu-based command controls, visual display of multi-modal medical images, 2D and 3D models of the surgical environment, graphical or tabulated information, visual alerts, etc., has been developed. Experiments of a simulated cryoablation of a tumor task have been performed with surgeons to evaluate the proposed surgical interface. Fixation durations and number of fixations at informative regions of the surgical interface have been analyzed, and these data are used to modify the surgical interface. Eye movement data has shown that participants concentrated their attention on informative regions more when the number of displayed Computer Tomography (CT) images has been reduced. Additionally, the time required to complete the kidney tumor cryoablation task by the participants had been decreased with the reduced number of CT images. Furthermore, the fixation durations obtained after the revision of the surgical interface are very close to what is observed in visual search and natural scene perception studies suggesting more efficient and comfortable interaction with the surgical interface. The National Aeronautics and Space Administration Task Load Index (NASA-TLX) and Short Post-Assessment Situational Awareness (SPASA) questionnaire results have shown that overall mental workload of surgeons related with surgical interface has been low as it has been aimed, and overall situational awareness scores of surgeons have been considerably high. This preliminary study highlights the improvement of a developed surgical interface using eye tracking technology to obtain the best SI configuration. The results presented here reveal that visual surgical interface design prepared according to eye movement characteristics may lead to improved usability.

Graphic Interfaces and Online Information.

ERIC Educational Resources Information Center

Percival, J. Mark

1990-01-01

Discusses the growing importance of the use of Graphic User Interfaces (GUIs) with microcomputers and online services. Highlights include the development of graphics interfacing with microcomputers; CD-ROM databases; an evaluation of HyperCard as a potential interface to electronic mail and online commercial databases; and future possibilities.…

The User Interface: How Does Your Product Look and Feel?

ERIC Educational Resources Information Center

Strukhoff, Roger

1987-01-01

Discusses the importance of user cordial interfaces to the successful marketing of optical data disk products, and describes features of several online systems. The topics discussed include full text searching, indexed searching, menu driven interfaces, natural language interfaces, computer graphics, and possible future developments. (CLB)

Factors affecting physicians' use of a dedicated overview interface in an electronic health record: The importance of standard information and standard documentation.

PubMed

Jensen, Lotte Groth; Bossen, Claus

2016-03-01

It remains a continual challenge to present information in user interfaces in large IT systems to support overview in the best possible way. We here examine how an electronic health record (EHR) supports the creation of overview among hospital physicians with a particular focus on the use of an interface designed to provide clinicians with a patient information overview. The overview interface integrates information flexibly from diverse places in the EHR and presents this information in one screen display. Our study revealed widespread non-use of the overview interface. We explore the reasons for its use and non-use. We conducted exploratory ethnographic fieldwork among physicians in two hospitals and gathered statistical data on their use of the overview interface. From the quantitative data, we identified where the interface was used most and conducted 18 semi-structured, open-ended interviews framed by the theoretical framework and the findings of the initial ethnographic fieldwork. We interviewed both physicians and employees from the IT units in different hospitals. We then analysed notes from the ethnographic fieldwork and the interviews and ordered these into themes forming the basis for the presentation of findings. The overview interface was most used in departments or situations where the problem at hand and the need for information could be standardized-in particular, in anesthesiological departments and outpatient clinics. However, departments with complex and long patient histories did not make much use of the overview interface. Design and layout were not mentioned as decisive factors affecting its use or non-use. Many physicians questioned the completeness of data in the overview interface-either because they were skeptical about the hospital's or the department's documentation practices, or because they could not recognize the structure of the interface. This uncertainty discouraged physicians from using the overview interface. Dedicating a specific function or interface to supporting overview works best where information needs can be standardized. The narrative and contextual nature of creating clinical overview is unlikely to be optimally supported by using the overview interface alone. The use of these kinds of interfaces requires trust in data completeness and other clinicians' and administrative staff's documentation practices, as well as an understanding of the underlying structure of the EHR and how information is filtered when data are aggregated for the interface. Copyright © 2015. Published by Elsevier Ireland Ltd.

The Effect of Prosthetic Socket Interface Design on Socket Comfort, Residual Limb Health, and Function for the Transfemoral Amputee

DTIC Science & Technology

2017-10-01

significantly lower trim lines, without ischial containment compared with a traditional interface. However, these alternative designs could compromise...overall function compared to the standard of care interface design . Therefore the focus of this clinical trial is to determine if the DS and Sub-I...alternative interface designs will improve socket comfort, residual limb health and function compared to the standard of care IRC interface design . 15

'Designing Ambient Interactions - Pervasive Ergonomic Interfaces for Ageing Well' (DAI'10)

NASA Astrophysics Data System (ADS)

Geven, Arjan; Prost, Sebastian; Tscheligi, Manfred; Soldatos, John; Gonzalez, Mari Feli

The workshop will focus on novel computer based interaction mechanisms and interfaces, which boost natural interactivity and obviate the need for conventional tedious interfaces. Such interfaces are increasingly used in ambient intelligence environments and related applications, including application boosting elderly cognitive support, cognitive rehabilitation and Ambient Assisted Living (AAL). The aim of the workshop is to provide insights on the technological underpinnings of such interfaces, along with tools and techniques for their design and evaluation.

mREST Interface Specification

NASA Technical Reports Server (NTRS)

McCartney, Patrick; MacLean, John

2012-01-01

mREST is an implementation of the REST architecture specific to the management and sharing of data in a system of logical elements. The purpose of this document is to clearly define the mREST interface protocol. The interface protocol covers all of the interaction between mREST clients and mREST servers. System-level requirements are not specifically addressed. In an mREST system, there are typically some backend interfaces between a Logical System Element (LSE) and the associated hardware/software system. For example, a network camera LSE would have a backend interface to the camera itself. These interfaces are specific to each type of LSE and are not covered in this document. There are also frontend interfaces that may exist in certain mREST manager applications. For example, an electronic procedure execution application may have a specialized interface for configuring the procedures. This interface would be application specific and outside of this document scope. mREST is intended to be a generic protocol which can be used in a wide variety of applications. A few scenarios are discussed to provide additional clarity but, in general, application-specific implementations of mREST are not specifically addressed. In short, this document is intended to provide all of the information necessary for an application developer to create mREST interface agents. This includes both mREST clients (mREST manager applications) and mREST servers (logical system elements, or LSEs).

Growth rates and interface shapes in germanium and lead tin telluride observed in-situ, real-time in vertical Bridgman furnaces

NASA Technical Reports Server (NTRS)

Barber, P. G.; Berry, R. F.; Debnam, W. J.; Fripp, A. L.; Woodell, G.; Simchick, R. T.

1995-01-01

Using the advanced technology developed to visualize the melt-solid interface in low Prandtl number materials, crystal growth rates and interface shapes have been measured in germanium and lead tin telluride semiconductors grown in vertical Bridgman furnaces. The experimental importance of using in-situ, real time observations to determine interface shapes, to measure crystal growth rates, and to improve furnace and ampoule designs is demonstrated. The interface shapes observed in-situ, in real-time were verified by quenching and mechanically induced interface demarcation, and they were also confirmed using machined models to ascertain the absence of geometric distortions. Interface shapes depended upon the interface position in the furnace insulation zone, varied with the nature of the crystal being grown, and were dependent on the extent of transition zones at the ends of the ampoule. Actual growth rates varied significantly from the constant translation rate in response to the thermophysical properties of the crystal and its melt and the thermal conditions existing in the furnace at the interface. In the elemental semiconductor germanium the observed rates of crystal growth exceeded the imposed translation rate, but in the compound semiconductor lead tin telluride the observed rates of growth were less than the translation rate. Finally, the extent of ampoule thermal loading influenced the interface positions, the shapes, and the growth rates.

Ordering Transitions in Liquid Crystals Permit Imaging of Spatial and Temporal Patterns Formed by Proteins Penetrating into Lipid-Laden Interfaces

PubMed Central

Daschner De Tercero, Maren; Abbott, Nicholas L.

2013-01-01

Recent studies have reported that full monolayers of L-α-dilaurylphosphatidylcholine (L-DLPC) and D-α-dipalmitoylphosphatidylcholine (D-DPPC) formed at interfaces between thermotropic liquid crystals (LCs) and aqueous phases lead to homeotropic (perpendicular) orientations of nematic LCs and that specific binding of proteins to these interfaces (such as phospholipase A2 binding to D-DPPC) can trigger orientational ordering transitions in the liquid crystals. We report on the nonspecific interactions of proteins with aqueous-LC interfaces decorated with partial monolayer coverage of L-DLPC. Whereas nonspecific interactions of four proteins (cytochrome c, bovine serum albumin,immunoglobulins, and neutravidin) do not perturb the ordering of the LC when a full monolayer of L-DLPC is assembled at the aqueous-LC interface, we observe patterned orientational transitions in the LC that reflect penetration of proteins into the interface of the LC with partial monolayer coverage of L-DLPC. The spatial patterns formed by the proteins and lipids at the interface are surprisingly complex, and in some cases the protein domains are found to compartmentalize lipid within the interfaces. These results suggest that phospholipid-decorated interfaces between thermotropic liquid crystals and aqueous phases offer the basis of a simple and versatile tool to study the spatial organization and dynamics ofprotein networks formed at mobile, lipid-decorated interfaces. PMID:23671353

GaN as an interfacial passivation layer: tuning band offset and removing fermi level pinning for III-V MOS devices.

PubMed

Zhang, Zhaofu; Cao, Ruyue; Wang, Changhong; Li, Hao-Bo; Dong, Hong; Wang, Wei-Hua; Lu, Feng; Cheng, Yahui; Xie, Xinjian; Liu, Hui; Cho, Kyeongjae; Wallace, Robert; Wang, Weichao

2015-03-11

The use of an interfacial passivation layer is one important strategy for achieving a high quality interface between high-k and III-V materials integrated into high-mobility metal-oxide-semiconductor field-effect transistor (MOSFET) devices. Here, we propose gallium nitride (GaN) as the interfacial layer between III-V materials and hafnium oxide (HfO2). Utilizing first-principles calculations, we explore the structural and electronic properties of the GaN/HfO2 interface with respect to the interfacial oxygen contents. In the O-rich condition, an O8 interface (eight oxygen atoms at the interface, corresponding to 100% oxygen concentration) displays the most stability. By reducing the interfacial O concentration from 100 to 25%, we find that the interface formation energy increases; when sublayer oxygen vacancies exist, the interface becomes even less stable compared with O8. The band offset is also observed to be highly dependent on the interfacial oxygen concentration. Further analysis of the electronic structure shows that no interface states are present at the O8 interface. These findings indicate that the O8 interface serves as a promising candidate for high quality III-V MOS devices. Moreover, interfacial states are present when such interfacial oxygen is partially removed. The interface states, leading to Fermi level pinning, originate from unsaturated interfacial Ga atoms.

The role of the interface in germanium quantum dots: when not only size matters for quantum confinement effects.

PubMed

Cosentino, S; Mio, A M; Barbagiovanni, E G; Raciti, R; Bahariqushchi, R; Miritello, M; Nicotra, G; Aydinli, A; Spinella, C; Terrasi, A; Mirabella, S

2015-07-14

Quantum confinement (QC) typically assumes a sharp interface between a nanostructure and its environment, leading to an abrupt change in the potential for confined electrons and holes. When the interface is not ideally sharp and clean, significant deviations from the QC rule appear and other parameters beyond the nanostructure size play a considerable role. In this work we elucidate the role of the interface on QC in Ge quantum dots (QDs) synthesized by rf-magnetron sputtering or plasma enhanced chemical vapor deposition (PECVD). Through a detailed electron energy loss spectroscopy (EELS) analysis we investigated the structural and chemical properties of QD interfaces. PECVD QDs exhibit a sharper interface compared to sputter ones, which also evidences a larger contribution of mixed Ge-oxide states. Such a difference strongly modifies the QC strength, as experimentally verified by light absorption spectroscopy. A large size-tuning of the optical bandgap and an increase in the oscillator strength occur when the interface is sharp. A spatially dependent effective mass (SPDEM) model is employed to account for the interface difference between Ge QDs, pointing out a larger reduction in the exciton effective mass in the sharper interface case. These results add new insights into the role of interfaces on confined systems, and open the route for reliable exploitation of QC effects.

Power and temperature dependent photoluminescence investigation of the linear polarization at normal and inverted interface transitions in InP/InAlAs and InGaAsP/InAlAs QW structures

NASA Astrophysics Data System (ADS)

Esmaielpour, Hamidreza; Whiteside, Vincent R.; Hirst, Louise C.; Forbes, David V.; Walters, Robert J.; Sellers, Ian R.

We present an investigation of the interface effects for InGaAsP/InAlAs QW and InP/InAlAs QW structures capped with an InP layer. Continuous wave photoluminescence (PL) spectroscopy of these samples at 4 K shows features associated with the interfaces of an InAlAs layer grown on an InP layer (normal interface) and an InP layer grown on an InAlAs material (inverted interface). Power dependent PL of the InGaAsP QW indicates that there are two features related to the inverted interface, whereby the linear polarization of one increases and for the other decreases. In addition, a temperature dependent study of this sample shows that as the temperature increases: the linear polarization for both features decreases; at room temperature, there is negligible polarization effect. A power dependent PL study of the InP QW structure shows both normal and inverted interface transitions have opposing trends in linear polarization. Notably, the temperature dependent PL investigation displays a reduction of polarization degree for the inverted interface: as expected; while an increase of polarization for the normal interface was observed. In addition, power and temperature dependence of peak energy of the interface transitions for both samples will be presented.

Blocking and Blending: Different Assembly Models of Cyclodextrin and Sodium Caseinate at the Oil/Water Interface.

PubMed

Xu, Hua-Neng; Liu, Huan-Huan; Zhang, Lianfu

2015-08-25

The stability of cyclodextrin (CD)-based emulsions is attributed to the formation of a solid film of oil-CD complexes at the oil/water interface. However, competitive interactions between CDs and other components at the interface still need to be understood. Here we develop two different routes that allow the incorporation of a model protein (sodium caseinate, SC) into emulsions based on β-CD. One route is the components adsorbed simultaneously from a mixed solution to the oil/water interface (route I), and the other is SC was added to a previously established CD-stabilized interface (route II). The adsorption mechanism of β-CD modified by SC at the oil/water interface is investigated by rheological and optical methods. Strong sensitivity of the rheological behavior to the routes is indicated by both steady-state and small-deformation oscillatory experiments. Possible β-CD/SC interaction models at the interface are proposed. In route I, the protein, due to its higher affinity for the interface, adsorbs strongly at the interface with blocking of the adsorption of β-CD and formation of oil-CD complexes. In route II, the protein penetrates and blends into the preadsorbed layer of oil-CD complexes already formed at the interface. The revelation of interfacial assembly is expected to help better understand CD-based emulsions in natural systems and improve their designs in engineering applications.

Multilayer multiferroic composites with imperfect interfaces

NASA Astrophysics Data System (ADS)

Kuo, Hsin-Yi; Wu, Tien-Jung; Pan, Ernian

2018-07-01

We study the macroscopic behaviors of multilayered multiferroic composites with interface imperfections by a direct micromechanical approach. Both generalized interface stress type and generalized linear spring type imperfect interfaces are considered. Concise matrix expressions of the overall behaviors of the layered piezoelectric–piezomagnetic composite with contact imperfection are presented. The key step is to observe that the two types of imperfect interface conditions are equivalent to the perfect ones due to the laminated geometry. Numerical calculations are demonstrated for BaTiO3–CoFe2O4 multilayer media, and are shown in good agreement with the more involved interphase model. Furthermore, it is observed that the interface imperfection would reduce the magnitude of the magnetoelectric voltage coefficients as compared to the corresponding perfect interface case. This feature is opposite to that predicted and observed in the corresponding cylindrical composites.

First-principles approach to calculating energy level alignment at aqueous semiconductor interfaces

DOE PAGES

Kharche, Neerav; Muckerman, James T.; Hybertsen, Mark S.

2014-10-21

A first-principles approach is demonstrated for calculating the relationship between an aqueous semiconductor interface structure and energy level alignment. The physical interface structure is sampled using density functional theory based molecular dynamics, yielding the interface electrostatic dipole. The GW approach from many-body perturbation theory is used to place the electronic band edge energies of the semiconductor relative to the occupied 1 b₁ energy level in water. The application to the specific cases of nonpolar (101¯0 ) facets of GaN and ZnO reveals a significant role for the structural motifs at the interface, including the degree of interface water dissociation andmore » the dynamical fluctuations in the interface Zn-O and O-H bond orientations. As a result, these effects contribute up to 0.5 eV.« less

Modeling Auditory-Haptic Interface Cues from an Analog Multi-line Telephone

NASA Technical Reports Server (NTRS)

Begault, Durand R.; Anderson, Mark R.; Bittner, Rachael M.

2012-01-01

The Western Electric Company produced a multi-line telephone during the 1940s-1970s using a six-button interface design that provided robust tactile, haptic and auditory cues regarding the "state" of the communication system. This multi-line telephone was used as a model for a trade study comparison of two interfaces: a touchscreen interface (iPad)) versus a pressure-sensitive strain gauge button interface (Phidget USB interface controllers). The experiment and its results are detailed in the authors' AES 133rd convention paper " Multimodal Information Management: Evaluation of Auditory and Haptic Cues for NextGen Communication Dispays". This Engineering Brief describes how the interface logic, visual indications, and auditory cues of the original telephone were synthesized using MAX/MSP, including the logic for line selection, line hold, and priority line activation.

Adhesion at WC/diamond interfaces - A theoretical study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Padmanabhan, Haricharan; Rao, M. S. Ramachandra; Nanda, B. R. K., E-mail: nandab@iitm.ac.in

2015-06-24

We investigate the adhesion at the interface of face-centered tungsten-carbide (001) and diamond (001) from density-functional calculations. Four high-symmetry model interfaces, representing different lattice orientations for either side of the interface, are constructed to incorporate different degrees of strain arising due to lattice mismatch. The adhesion, estimated from the ideal work of separation, is found to be in the range of 4 - 7 J m{sup −2} and is comparable to that of metal-carbide interfaces. Maximum adhesion occurs when WC and diamond slabs have the same orientation, even though such a growth induces large epitaxial strain at the interface. Frommore » electronic structure calculations, we attribute the adhesion to covalent interaction between carbon p-orbitals as well as partial ionic interaction between the tungsten d- and carbon p-orbitals across the interface.« less

Elastic and piezoelectric fields around a quantum wire of zincblende heterostructures with interface elasticity effect

NASA Astrophysics Data System (ADS)

Ye, Wei; Liu, Yifei

2018-04-01

This work formulates the solutions to the elastic and piezoelectric fields around a quantum wire (QWR) with interface elasticity effect. Closed-form solutions to the piezoelectric potential field of zincblende QWR/matrix heterostructures grown along [111] crystallographic orientation are found and numerical results of InAs/InP heterostructures are provided as an example. The piezoelectric potential in the matrix depends on the interface elasticity, the radius and stiffness of the QWR. Our results indicate that interface elasticity can significantly alter the elastic and piezoelectric fields near the interface. Additionally, when the elastic property of the QWR is considered to be anisotropic in contrary to the common isotropic assumption, piezoelectric potentials are found to be distinct near the interface, but the deviations are negligible at positions far away from the interface.

Quantitative first-principles theory of interface absorption in multilayer heterostructures

DOE PAGES

Hachtel, Jordan A.; Sachan, Ritesh; Mishra, Rohan; ...

2015-09-03

The unique chemical bonds and electronic states of interfaces result in optical properties that are different from those of the constituting bulk materials. In the nanoscale regime, the interface effects can be dominant and impact the optical response of devices. Using density functional theory (DFT), the interface effects can be calculated, but DFT is computationally limited to small systems. In this paper, we describe a method to combine DFT with macroscopic methodologies to extract the interface effect on absorption in a consistent and quantifiable manner. The extracted interface effects are an independent parameter and can be applied to more complicatedmore » systems. Finally, we demonstrate, using NiSi 2/Si heterostructures, that by varying the relative volume fractions of interface and bulk, we can tune the spectral range of the heterostructure absorption.« less

Interface investigation of solution processed high- κ ZrO2/Si MOS structure by DLTS

NASA Astrophysics Data System (ADS)

Kumar, Arvind; Mondal, Sandip; Rao, Ksr Koteswara

The interfacial region is dominating due to the continuous downscaling and integration of high- k oxides in CMOS applications. The accurate characterization of high- k oxides/semiconductor interface has the significant importance towards its usage in memory and thin film devices. The interface traps at the high - k /semiconductor interface can be quantified by deep level transient spectroscopy (DLTS) with better accuracy in contrast to capacitance-voltage (CV) and conductance technique. We report the fabrication of high- k ZrO2 films on p-Si substrate by a simple and inexpensive sol-gel spin-coating technique. Further, the ZrO2/Si interface is characterized through DLTS. The flat-band voltage (VFB) and the density of slow interface states (oxide trapped charges) extracted from CV characteristics are 0.37 V and 2x10- 11 C/cm2, respectively. The activation energy, interface state density and capture cross-section quantified by DLTS are EV + 0.42 eV, 3.4x1011 eV- 1 cm- 2 and 5.8x10- 18 cm2, respectively. The high quality ZrO2 films own high dielectric constant 15 with low leakage current density might be an appropriate insulating layer in future electronic application. The low value of interface state density and capture cross-section are the indication of high quality interface and the defect present at the interface may not affect the device performance to a great extent. The DLTS study provides a broad understanding about the traps present at the interface of spin-coated ZrO2/Si.

Using hub technology to facilitate information system integration in a health-care enterprise.

PubMed

Gendler, S M; Friedman, B A; Henricks, W H

1996-04-01

The deployment and maintenance of multiple point-to-point interfaces between a clinical information system, such as a laboratory information system, and other systems within a healthcare enterprise is expensive and time consuming. Moreover, the demand for such interfaces is increasing as hospitals consolidate and clinical laboratories participate in the development of regional laboratory networks and create host-to-host links with laboratory outreach clients. An interface engine, also called a hub, is an evolving technology that could replace multiple point-to-point interfaces from a laboratory information system with a single interface to the hub, preferably HL7 based. The hub then routes and translates laboratory information to other systems within the enterprise. Changes in application systems in an enterprise where a centralized interface engine has been implemented then amount to thorough analysis, an update of the enterprise's data dictionary, purchase of a single new vendor-supported interface, and table-based parameter changes on the hub. Two other features of an interface engine, support for structured query language and information store-and-forward, will facilitate the development of clinical data repositories and provide flexibility when interacting with other host systems. This article describes the advantages and disadvantages of an interface engine and lists some problems not solved by the technology. Finally, early developmental experience with an interface engine at the University of Michigan Medical Center and the benefits of the project on system integration efforts are described, not the least of which has been the enthusiastic adoption of the HL7 standard for all future interface projects.

Interface waves in multilayered plates.

PubMed

Li, Bing; Li, Ming-Hang; Lu, Tong

2018-04-01

In this paper, the characteristic equation of interface waves in multilayered plates is derived. With a reasonable assumption undertaken for the potential functions of longitudinal and shear waves in the nth layer medium, the characteristic equation of interface waves in the N-layered plate is derived and presented in a determinant form. The particle displacement and stress components are further presented in explicit forms. The dispersion curves and wave structures of interface waves in both a three-layered Al-Steel-Ti and a four-layered Steel-Al-Steel-Ti plate are displayed subsequently. It is observed in dispersion curves that obvious dispersion occurs on the low frequency band, whereas the phase velocities converge to the corresponding true Stoneley wave mode velocities at high frequency, and the number of interface wave modes equals the number of interfaces in multilayered plates (if all individual interfaces satisfy the existence condition of Stoneley waves). The wave structures reveal that the displacement components of interface waves are relatively high at interfaces, and the amplitude distribution varies from frequency to frequency. In the end, a similarly structured three-layered Al-Steel-Ti plate is tested. In this experiment, theoretical group velocity and experimental group velocity are compared. According to the discussion and comparison, the predicted group velocities are in good agreement with the experimental results. Thus, the theory of interface wave in multilayered plates is proved. As a result, the proposed theoretical approach represents a leap forward in the understanding of how to promote the characteristic study and practical applications of interface waves in multilayered structures.

Graphical Interfaces for Simulation.

ERIC Educational Resources Information Center

Hollan, J. D.; And Others

This document presents a discussion of the development of a set of software tools to assist in the construction of interfaces to simulations and real-time systems. Presuppositions to the approach to interface design that was used are surveyed, the tools are described, and the conclusions drawn from these experiences in graphical interface design…

Graphical User Interface Programming in Introductory Computer Science.

ERIC Educational Resources Information Center

Skolnick, Michael M.; Spooner, David L.

Modern computing systems exploit graphical user interfaces for interaction with users; as a result, introductory computer science courses must begin to teach the principles underlying such interfaces. This paper presents an approach to graphical user interface (GUI) implementation that is simple enough for beginning students to understand, yet…

78 FR 36541 - Public Interface Control Working Group (ICWG) Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-18

... DEPARTMENT OF DEFENSE Department of the Air Force Public Interface Control Working Group (ICWG... Systems (GPS) Directorate will be hosting a Public Interface Control Working Group (ICWG) meeting for the....mil by August 7, 2013. Public Interface Control Working Group Meeting (ICWG) Date(s) and Times: 24-25...

40 CFR 80.84 - Treatment of interface and transmix.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Treatment of interface and transmix... interface and transmix. (a) Definitions. For purposes of this section, the following definitions apply: (1) Interface means a volume of petroleum product generated in a pipeline between two adjacent volumes of non...

Toward High-Performance Communications Interfaces for Science Problem Solving

ERIC Educational Resources Information Center

Oviatt, Sharon L.; Cohen, Adrienne O.

2010-01-01

From a theoretical viewpoint, educational interfaces that facilitate communicative actions involving representations central to a domain can maximize students' effort associated with constructing new schemas. In addition, interfaces that minimize working memory demands due to the interface per se, for example by mimicking existing non-digital work…

Protein-protein interfaces are vdW dominant with selective H-bonds and (or) electrostatics towards broad functional specificity.

PubMed

Nilofer, Christina; Sukhwal, Anshul; Mohanapriya, Arumugam; Kangueane, Pandjassarame

2017-01-01

Several catalysis, cellular regulation, immune function, cell wall assembly, transport, signaling and inhibition occur through Protein- Protein Interactions (PPI). This is possible with the formation of specific yet stable protein-protein interfaces. Therefore, it is of interest to understand its molecular principles using structural data in relation to known function. Several interface features have been documented using known X-ray structures of protein complexes since 1975. This has improved our understanding of the interface using structural features such as interface area, binding energy, hydrophobicity, relative hydrophobicity, salt bridges and hydrogen bonds. The strength of binding between two proteins is dependent on interface size (number of residues at the interface) and thus its corresponding interface area. It is known that large interfaces have high binding energy (sum of (van der Waals) vdW, H-bonds, electrostatics). However, the selective role played by each of these energy components and more especially that of vdW is not explicitly known. Therefore, it is important to document their individual role in known protein-protein structural complexes. It is of interest to relate interface size with vdW, H-bonds and electrostatic interactions at the interfaces of protein structural complexes with known function using statistical and multiple linear regression analysis methods to identify the prominent force. We used the manually curated non-redundant dataset of 278 hetero-dimeric protein structural complexes grouped using known functions by Sowmya et al. (2015) to gain additional insight to this phenomenon using a robust inter-atomic non-covalent interaction analyzing tool PPCheck (Anshul and Sowdhamini, 2015). This dataset consists of obligatory (enzymes, regulator, biological assembly), immune and nonobligatory (enzyme and regulator inhibitors) complexes. Results show that the total binding energy is more for large interfaces. However, this is not true for its individual energy factors. Analysis shows that vdW energies contribute to about 75% ± 11% on average among all complexes and it also increases with interface size (r2 ranging from 0.67 to 0.89 with p<0.01) at 95% confidence limit irrespective of molecular function. Thus, vdW is both dominant and proportional at the interface independent of molecular function. Nevertheless, H bond energy contributes to 15% ± 6.5% on average in these complexes. It also moderately increases with interface size (r2 ranging from 0.43 to 0.61 with p<0.01) only among obligatory and immune complexes. Moreover, there is about 11.3% ± 8.7% contribution by electrostatic energy. It increases with interface size specifically among non-obligatory regulator-inhibitors (r2 = 0.44). It is implied that both H-bonds and electrostatics are neither dominant nor proportional at the interface. Nonetheless, their presence cannot be ignored in binding. Therefore, H-bonds and (or) electrostatic energy having specific role for improved stability in complexes is implied. Thus, vdW is common at the interface stabilized further with selective H-bonds and (or) electrostatic interactions at an atomic level in almost all complexes. Comparison of this observation with residue level analysis of the interface is compelling. The role by H-bonds (14.83% ± 6.5% and r2 = 0.61 with p<0.01) among obligatory and electrostatic energy (8.8% ± 4.77% and r2 = 0.63 with p <0.01) among non-obligatory complexes within interfaces (class A) having more non-polar residues than surface is influencing our inference. However, interfaces (class B) having less non-polar residues than surface show 1.5 fold more electrostatic energy on average. The interpretation of the interface using inter-atomic (vdW, H-bonds, electrostatic) interactions combined with inter-residue predominance (class A and class B) in relation to known function is the key to reveal its molecular principles with new challenges.

Optical second harmonic generation phase measurement at interfaces of some organic layers with indium tin oxide

NASA Astrophysics Data System (ADS)

Ngah Demon, Siti Zulaikha; Miyauchi, Yoshihiro; Mizutani, Goro; Matsushima, Toshinori; Murata, Hideyuki

2014-08-01

We observed phase shift in optical second harmonic generation (SHG) from interfaces of indium tin oxide (ITO)/copper phthalocyanine (CuPc) and ITO/pentacene. Phase correction due to Fresnel factors of the sample was taken into account. The phase of SHG electric field at the ITO/pentacene interface, ϕinterface with respect to the phase of SHG of bare substrate ITO was 160°, while the interface of ITO/CuPc had a phase of 140°.

Convection-induced distortion of a solid-liquid interface

NASA Technical Reports Server (NTRS)

Schaefer, R. J.; Coriell, S. R.

1984-01-01

Measurements of convective flow fields and solid-liquid interface shapes during the solidification of a pure and a slightly alloyed transparent material reveal that the convective transport of solute can cause a macroscopic depression to develop in the solid-liquid interface. This effect occurs under conditions close to those which are predicted to produce morphological instability of a planar interface. A cellular or dendritic microstructure later develops within the interface depression. The convection is attributed to the effect of radial temperature gradients in the crystal growth apparatus.

Bi-directional communication interface for microprocessor-to-system/370

NASA Technical Reports Server (NTRS)

Fischer, J. P.

1981-01-01

The design and operation of a bi-directional communication interface between a microcomputer and the IBM System/370 is documented. The hardware unit interconnects a modem to interface to the S/370, the microcomputer with an EIA I/O port, and a terminal for sending and receiving data from either the microcomputer or the S/370. Also described is the software necessary for the two-way interface. This interface is designed so that no modifications need to be made to the terminal, modem, or microcomputer.

Interface-induced localization in AlSb/InAs heterostructures

NASA Astrophysics Data System (ADS)

Shaw, M. J.; Briddon, P. R.; Jaros, M.

1995-12-01

The existence of localized states at perfect InSb-like interfaces in AlSb/InAs superlattices is predicted from ab initio pseudopotential calculations. Localized states are predicted in both the valence and conduction bands, the former being identifiable with the interface states proposed by Kroemer, Nguyen, and Brar [J. Vac. Sci. Technol. 10, 1769 (1990)]. The existence of these interface localized states is invoked to explain the reported experimental dependence of the band gap upon interface types in such superlattices.

Thermal Stir Welder

NASA Technical Reports Server (NTRS)

Ding, R. Jeffrey (Inventor)

2012-01-01

A welding apparatus is provided for forming a weld joint between first and second elements of a workpiece. The apparatus heats the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding mixer, to remove any dendritic-type weld microstructures introduced into the interface material during heating.

Positron annihilation at the Si/SiO2 interface

NASA Astrophysics Data System (ADS)

Leung, T. C.; Weinberg, Z. A.; Asoka-Kumar, P.; Nielsen, B.; Rubloff, G. W.; Lynn, K. G.

1992-01-01

Variable-energy positron annihilation depth-profiling has been applied to the study of the Si/SiO2 interface in Al-gate metal-oxide-semiconductor (MOS) structures. For both n- and p-type silicon under conditions of negative gate bias, the positron annihilation S-factor characteristic of the interface (Sint) is substantially modified. Temperature and annealing behavior, combined with known MOS physics, suggest strongly that Sint depends directly on holes at interface states or traps at the Si/SiO2 interface.

Development of a task analysis tool to facilitate user interface design

NASA Technical Reports Server (NTRS)

Scholtz, Jean C.

1992-01-01

A good user interface is one that facilitates the user in carrying out his task. Such interfaces are difficult and costly to produce. The most important aspect in producing a good interface is the ability to communicate to the software designers what the user's task is. The Task Analysis Tool is a system for cooperative task analysis and specification of the user interface requirements. This tool is intended to serve as a guide to development of initial prototypes for user feedback.

A generic interface element for COMET-AR

NASA Technical Reports Server (NTRS)

Mccleary, Susan L.; Aminpour, Mohammad A.

1995-01-01

The implementation of an interface element capability within the COMET-AR software system is described. The report is intended for use by both users of currently implemented interface elements and developers of new interface element formulations. Guidance on the use of COMET-AR is given. A glossary is provided as an Appendix to this report for readers unfamiliar with the jargon of COMET-AR. A summary of the currently implemented interface element formulation is presented in Section 7.3 of this report.

Production and Perception of Distortion in Word-Initial Friction Duration

ERIC Educational Resources Information Center

Jovicic, Slobodan T.; Kasic, Zorca; Punisic, Silvana

2010-01-01

The purpose of the present study was to investigate (a) the distortion in production of word-initial friction duration in fricative /[esh]/, and (b) the perceptual discrimination between typical (normal) and atypical (prolonged or lengthened) friction duration. In the first experiment 80 school aged children pronounced word /[esh]uma/, 40 of them…

77 FR 59444 - Self-Regulatory Organizations; Chicago Board Options Exchange, Incorporated; Notice of Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-27

... provides a ``menu'' of matching algorithms to choose from when executing incoming electronic orders. The menu format allows the Exchange to utilize different matching algorithms on a class-by-class basis. The menu includes, among other choices, the ultimate matching algorithm (``UMA''), as well as price-time...

The Shaping of Postcollege Colorblind Orientation among Whites: Residential Segregation and Campus Diversity Experiences

ERIC Educational Resources Information Center

Jayakumar, Uma M.

2015-01-01

In this article, Uma M. Jayakumar investigates the cumulative impact of experiences with segregation or racial diversity prior to and during college on colorblind ideological orientation among white adults. An analysis of longitudinal data spanning ten years reveals that, for whites from segregated and diverse childhood neighborhoods, some…

X-ray and optical observations of the ultrashort period dwarf nova SW Ursae Majoris - A likely new DQ Herculis star

NASA Technical Reports Server (NTRS)

Shafter, A. W.; Szkody, P.; Thorstensen, J. R.

1986-01-01

Time-resolved X-ray and optical photometric and optical spectroscopic observations of the ultrashort period cataclysmic variable SW UMa are reported. The spectroscopic observations reveal the presence of an s-wave component which is almost in phase with the extreme line wings and presumably the white dwarf. This very unusual phasing in conjunction with the available optical and X-ray data seems to indicate that a region of enhanced emission exists on the opposite side of the disk from the expected location of the hot spot. The photometric observations reveal the presence of a hump in the light curve occurring at an orbital phase which is consistent with the phase at which the region of enhanced line emission is most favorably seen. Changes in the hump amplitude are seen from night to night, and a 15.9 min periodicity is evident in the light curve. The optical and X-ray periodicities suggest that SW UMa is a member of the DQ Her class of cataclysmic variables.

Secure transport and adaptation of MC-EZBC video utilizing H.264-based transport protocols☆

PubMed Central

Hellwagner, Hermann; Hofbauer, Heinz; Kuschnig, Robert; Stütz, Thomas; Uhl, Andreas

2012-01-01

Universal Multimedia Access (UMA) calls for solutions where content is created once and subsequently adapted to given requirements. With regard to UMA and scalability, which is required often due to a wide variety of end clients, the best suited codecs are wavelet based (like the MC-EZBC) due to their inherent high number of scaling options. However, most transport technologies for delivering videos to end clients are targeted toward the H.264/AVC standard or, if scalability is required, the H.264/SVC. In this paper we will introduce a mapping of the MC-EZBC bitstream to existing H.264/SVC based streaming and scaling protocols. This enables the use of highly scalable wavelet based codecs on the one hand and the utilization of already existing network technologies without accruing high implementation costs on the other hand. Furthermore, we will evaluate different scaling options in order to choose the best option for given requirements. Additionally, we will evaluate different encryption options based on transport and bitstream encryption for use cases where digital rights management is required. PMID:26869746

Rare case of nephrotic syndrome: Schimke syndrome.

PubMed

Pedrosa, Anna Kelly Krislane de Vasconcelos; Torres, Luiz Fernando Oliveira; Silva, Ana Corina Brainer Amorim da; Dantas, Adrianna Barros Leal; Zuntini, Káthia Liliane da Cunha Ribeiro; Aguiar, Lia Cordeiro Bastos

2016-01-01

Schimke syndrome corresponds to dysplasia of bone and immunity, associated with progressive renal disease secondary to nephrotic syndrome cortico-resistant, with possible other abnormalities such as hypothyroidism and blond marrow aplasia. It is a rare genetic disorder, with few reports in the literature. The most frequent renal involvement is nephrotic syndrome with focal segmental glomerulosclerosis and progressive renal failure. The objective of this study was to report a case of Schimke syndrome, diagnostic investigation and management of the case. Resumo A síndrome Schimke corresponde à displasia imuno-óssea, associada à doença renal progressiva secundária à síndrome nefrótica córtico-resistente, podendo haver outras anormalidades como hipotireoidismo e aplasia de medula óssea. Trata-se de uma patologia genética rara, com poucos relatos na literatura. O acometimento renal mais frequente é uma síndrome nefrótica por glomeruloesclerose segmentar e focal e falência renal progressiva. O objetivo deste estudo foi relatar um caso de síndrome de Schimke, investigação diagnóstica e condução do caso.

Photometric study and absolute parameters of the short-period eclipsing binary HH Bootis

NASA Astrophysics Data System (ADS)

Gürol, B.; Bradstreet, D. H.; Demircan, Y.; Gürsoytrak, S. H.

2015-11-01

We present the results of our investigation on the geometrical and physical parameters of the W UMa type binary system HH Bootis from new CCD (BVRI) light curves and published radial velocity data. The photometric data were obtained in 2011 and 2012 at Ankara University Observatory (AUO). Light and radial velocity observations were analyzed simultaneously using the Wilson-Devinney (2013 revision) code to obtain absolute and geometrical parameters. The system was determined to be a W-type W UMa system of a type different from that suggested by Dal and Sipahi (2013). An interesting cyclic period variation in the time intervals between primary and secondary eclipses ("half-period variation") was discovered and analyzed and its possible cause is discussed. Combining our photometric solution with the spectroscopic data we derived masses and radii of the eclipsing system to be M1 = 0.627M⊙ , M2 = 1.068M⊙ , R1 = 0.782R⊙ and R2 = 0.997R⊙ . New light elements were derived and finally the evolutionary status of the system is discussed.

Indirect dark matter searches in the dwarf satellite galaxy Ursa Major II with the MAGIC telescopes

NASA Astrophysics Data System (ADS)

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Baack, D.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berse, R. Ch.; Berti, A.; Bhattacharyya, W.; Biland, A.; Blanch, O.; Bonnoli, G.; Carosi, R.; Carosi, A.; Ceribella, G.; Chatterjee, A.; Colak, S. M.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; Delfino, M.; Delgado, J.; Di Pierro, F.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Elsaesser, D.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Ishio, K.; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Masuda, S.; Mazin, D.; Mielke, K.; Minev, M.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Nagayoshi, T.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nigro, C.; Nilsson, K.; Ninci, D.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pedaletti, G.; Peresano, M.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Righi, C.; Rugliancich, A.; Saito, T.; Satalecka, K.; Schweizer, T.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takahashi, M.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Teshima, M.; Torres-Albà, N.; Treves, A.; Tsujimoto, S.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Zarić, D.

2018-03-01

The dwarf spheroidal galaxy Ursa Major II (UMaII) is believed to be one of the most dark-matter dominated systems among the Milky Way satellites and represents a suitable target for indirect dark matter (DM) searches. The MAGIC telescopes carried out a deep observation campaign on UMaII between 2014 and 2016, collecting almost one hundred hours of good-quality data. This campaign enlarges the pool of DM targets observed at very high energy (E gtrsim 50 GeV) in search for signatures of DM annihilation in the wide mass range between ~100 GeV and ~100 TeV. To this end, the data are analyzed with the full likelihood analysis, a method based on the exploitation of the spectral information of the recorded events for an optimal sensitivity to the explored DM models. We obtain constraints on the annihilation cross-section for different channels that are among the most robust and stringent achieved so far at the TeV mass scale from observations of dwarf satellite galaxies.

Multi-modal virtual environment research at Armstrong Laboratory

NASA Technical Reports Server (NTRS)

Eggleston, Robert G.

1995-01-01

One mission of the Paul M. Fitts Human Engineering Division of Armstrong Laboratory is to improve the user interface for complex systems through user-centered exploratory development and research activities. In support of this goal, many current projects attempt to advance and exploit user-interface concepts made possible by virtual reality (VR) technologies. Virtual environments may be used as a general purpose interface medium, an alternative display/control method, a data visualization and analysis tool, or a graphically based performance assessment tool. An overview is given of research projects within the division on prototype interface hardware/software development, integrated interface concept development, interface design and evaluation tool development, and user and mission performance evaluation tool development.

Interface Generation and Compositional Verification in JavaPathfinder

NASA Technical Reports Server (NTRS)

Giannakopoulou, Dimitra; Pasareanu, Corina

2009-01-01

We present a novel algorithm for interface generation of software components. Given a component, our algorithm uses learning techniques to compute a permissive interface representing legal usage of the component. Unlike our previous work, this algorithm does not require knowledge about the component s environment. Furthermore, in contrast to other related approaches, our algorithm computes permissive interfaces even in the presence of non-determinism in the component. Our algorithm is implemented in the JavaPathfinder model checking framework for UML statechart components. We have also added support for automated assume-guarantee style compositional verification in JavaPathfinder, using component interfaces. We report on the application of the presented approach to the generation of interfaces for flight software components.

Finite element modeling of frictionally restrained composite interfaces

NASA Technical Reports Server (NTRS)

Ballarini, Roberto; Ahmed, Shamim

1989-01-01

The use of special interface finite elements to model frictional restraint in composite interfaces is described. These elements simulate Coulomb friction at the interface, and are incorporated into a standard finite element analysis of a two-dimensional isolated fiber pullout test. Various interfacial characteristics, such as the distribution of stresses at the interface, the extent of slip and delamination, load diffusion from fiber to matrix, and the amount of fiber extraction or depression are studied for different friction coefficients. The results are compared to those obtained analytically using a singular integral equation approach, and those obtained by assuming a constant interface shear strength. The usefulness of these elements in micromechanical modeling of fiber-reinforced composite materials is highlighted.

The Body-Machine Interface: A new perspective on an old theme

PubMed Central

Casadio, Maura; Ranganathan, Rajiv; Mussa-Ivaldi, Ferdinando A.

2012-01-01

Body-machine interfaces establish a way to interact with a variety of devices, allowing their users to extend the limits of their performance. Recent advances in this field, ranging from computer-interfaces to bionic limbs, have had important consequences for people with movement disorders. In this article, we provide an overview of the basic concepts underlying the body-machine interface with special emphasis on their use for rehabilitation and for operating assistive devices. We outline the steps involved in building such an interface and we highlight the critical role of body-machine interfaces in addressing theoretical issues in motor control as well as their utility in movement rehabilitation. PMID:23237465

fgui: A Method for Automatically Creating Graphical User Interfaces for Command-Line R Packages

PubMed Central

Hoffmann, Thomas J.; Laird, Nan M.

2009-01-01

The fgui R package is designed for developers of R packages, to help rapidly, and sometimes fully automatically, create a graphical user interface for a command line R package. The interface is built upon the Tcl/Tk graphical interface included in R. The package further facilitates the developer by loading in the help files from the command line functions to provide context sensitive help to the user with no additional effort from the developer. Passing a function as the argument to the routines in the fgui package creates a graphical interface for the function, and further options are available to tweak this interface for those who want more flexibility. PMID:21625291

Electronic structure and relative stability of the coherent and semi-coherent HfO2/III-V interfaces

NASA Astrophysics Data System (ADS)

Lahti, A.; Levämäki, H.; Mäkelä, J.; Tuominen, M.; Yasir, M.; Dahl, J.; Kuzmin, M.; Laukkanen, P.; Kokko, K.; Punkkinen, M. P. J.

2018-01-01

III-V semiconductors are prominent alternatives to silicon in metal oxide semiconductor devices. Hafnium dioxide (HfO2) is a promising oxide with a high dielectric constant to replace silicon dioxide (SiO2). The potentiality of the oxide/III-V semiconductor interfaces is diminished due to high density of defects leading to the Fermi level pinning. The character of the harmful defects has been intensively debated. It is very important to understand thermodynamics and atomic structures of the interfaces to interpret experiments and design methods to reduce the defect density. Various realistic gap defect state free models for the HfO2/III-V(100) interfaces are presented. Relative energies of several coherent and semi-coherent oxide/III-V semiconductor interfaces are determined for the first time. The coherent and semi-coherent interfaces represent the main interface types, based on the Ga-O bridges and As (P) dimers, respectively.

Interface Reactions and Synthetic Reaction of Composite Systems

PubMed Central

Park, Joon Sik; Kim, Jeong Min

2010-01-01

Interface reactions in composite systems often determine their overall properties, since product phases usually formed at interfaces during composite fabrication processing make up a large portion of the composites. Since most composite materials represent a ternary or higher order materials system, many studies have focused on analyses of diffusion phenomena and kinetics in multicomponent systems. However, the understanding of the kinetic behavior increases the complexity, since the kinetics of each component during interdiffusion reactions need to be defined for interpreting composite behaviors. From this standpoint, it is important to clarify the interface reactions for producing compatible interfaces with desired product phases. A thermodynamic evaluation such as a chemical potential of involving components can provide an understanding of the diffusion reactions, which govern diffusion pathways and product phase formation. A strategic approach for designing compatible interfaces is discussed in terms of chemical potential diagrams and interface morphology, with some material examples.

Experimental metrology to obtain thermal phonon transmission coefficients at solid interfaces

NASA Astrophysics Data System (ADS)

Hua, Chengyun; Chen, Xiangwen; Ravichandran, Navaneetha K.; Minnich, Austin J.

2017-05-01

Interfaces play an essential role in phonon-mediated heat conduction in solids, impacting applications ranging from thermoelectric waste heat recovery to heat dissipation in electronics. From the microscopic perspective, interfacial phonon transport is described by transmission coefficients that link vibrational modes in the materials composing the interface. However, direct experimental determination of these coefficients is challenging because most experiments provide a mode-averaged interface conductance that obscures the microscopic detail. Here, we report a metrology to extract thermal phonon transmission coefficients at solid interfaces using ab initio phonon transport modeling and a thermal characterization technique, time-domain thermoreflectance. In combination with transmission electron microscopy characterization of the interface, our approach allows us to link the atomic structure of an interface to the spectral content of the heat crossing it. Our work provides a useful perspective on the microscopic processes governing interfacial heat conduction.

Development of an interface-focused educational complex intervention.

PubMed

Sampson, Rod; MacVicar, Ronald; Wilson, Philip

2017-09-01

In many countries, the medical primary-secondary care interface is central to the delivery of quality patient care. There is prevailing interest in developing initiatives to improve interface working for the benefit of health care professionals and their patients. To describe the development of an educational intervention designed to improve working at the primary-secondary care interface in NHS Scotland (United Kingdom) within the context of the Medical Research Council framework for the development and evaluation of complex interventions. A primary-secondary care interface focused Practice-based Small Group Learning (PBSGL) module was developed building upon qualitative synthesis and original research. A 'meeting of experts' shaped the module, which was subsequently piloted with a group of interface clinicians. Reflections on the module were sought from clinicians across NHS Scotland to provide contextual information from other areas. The PBSGL approach can be usefully applied to the development of a primary-secondary care interface-focused medical educational intervention.

Local intelligent electronic device (IED) rendering templates over limited bandwidth communication link to manage remote IED

DOEpatents

Bradetich, Ryan; Dearien, Jason A; Grussling, Barry Jakob; Remaley, Gavin

2013-11-05

The present disclosure provides systems and methods for remote device management. According to various embodiments, a local intelligent electronic device (IED) may be in communication with a remote IED via a limited bandwidth communication link, such as a serial link. The limited bandwidth communication link may not support traditional remote management interfaces. According to one embodiment, a local IED may present an operator with a management interface for a remote IED by rendering locally stored templates. The local IED may render the locally stored templates using sparse data obtained from the remote IED. According to various embodiments, the management interface may be a web client interface and/or an HTML interface. The bandwidth required to present a remote management interface may be significantly reduced by rendering locally stored templates rather than requesting an entire management interface from the remote IED. According to various embodiments, an IED may comprise an encryption transceiver.

Shock wave refraction enhancing conditions on an extended interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Markhotok, A.; Popovic, S.

2013-04-15

We determined the law of shock wave refraction for a class of extended interfaces with continuously variable gradients. When the interface is extended or when the gas parameters vary fast enough, the interface cannot be considered as sharp or smooth and the existing calculation methods cannot be applied. The expressions we derived are general enough to cover all three types of the interface and are valid for any law of continuously varying parameters. We apply the equations to the case of exponentially increasing temperature on the boundary and compare the results for all three types of interfaces. We have demonstratedmore » that the type of interface can increase or inhibit the shock wave refraction. Our findings can be helpful in understanding the results obtained in energy deposition experiments as well as for controlling the shock-plasma interaction in other settings.« less

Hybrid method for moving interface problems with application to the Hele-Shaw flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hou, T.Y.; Li, Zhilin; Osher, S.

In this paper, a hybrid approach which combines the immersed interface method with the level set approach is presented. The fast version of the immersed interface method is used to solve the differential equations whose solutions and their derivatives may be discontinuous across the interfaces due to the discontinuity of the coefficients or/and singular sources along the interfaces. The moving interfaces then are updated using the newly developed fast level set formulation which involves computation only inside some small tubes containing the interfaces. This method combines the advantage of the two approaches and gives a second-order Eulerian discretization for interfacemore » problems. Several key steps in the implementation are addressed in detail. This new approach is then applied to Hele-Shaw flow, an unstable flow involving two fluids with very different viscosity. 40 refs., 10 figs., 3 tabs.« less

Advanced aerosense display interfaces

NASA Astrophysics Data System (ADS)

Hopper, Darrel G.; Meyer, Frederick M.

1998-09-01

High-resolution display technologies are being developed to meet the ever-increasing demand for realistic detail. The requirement for evermore visual information exceeds the capacity of fielded aerospace display interfaces. In this paper we begin an exploration of display interfaces and evolving aerospace requirements. Current and evolving standards for avionics, commercial, and flat panel displays are summarized and compared to near term goals for military and aerospace applications. Aerospace and military applications prior to 2005 up to UXGA and digital HDTV resolution can be met by using commercial interface standard developments. Advanced aerospace requirements require yet higher resolutions (2560 X 2048 color pixels, 5120 X 4096 color pixels at 85 Hz, etc.) and necessitate the initiation of discussion herein of an 'ultra digital interface standard (UDIS)' which includes 'smart interface' features such as large memory and blazingly fast resizing microcomputer. Interface capacity, IT, increased about 105 from 1973 to 1998; 102 more is needed for UDIS.

Interaction of a sodium ion with the water liquid-vapor interface

NASA Technical Reports Server (NTRS)

Wilson, M. A.; Pohorille, A.; Pratt, L. R.; MacElroy, R. D. (Principal Investigator)

1989-01-01

Molecular dynamics results are presented for the density profile of a sodium ion near the water liquid-vapor interface at 320 K. These results are compared with the predictions of a simple dielectric model for the interaction of a monovalent ion with this interface. The interfacial region described by the model profile is too narrow and the profile decreases too abruptly near the solution interface. Thus, the simple model does not provide a satisfactory description of the molecular dynamics results for ion positions within two molecular diameters from the solution interface where appreciable ion concentrations are observed. These results suggest that surfaces associated with dielectric models of ionic processes at aqueous solution interfaces should be located at least two molecular diameters inside the liquid phase. A free energy expense of about 2 kcal/mol is required to move the ion within two molecular layers of the free water liquid-vapor interface.

Magnetocapacitance and the physics of solid state interfaces

NASA Astrophysics Data System (ADS)

Hebard, Arthur

2008-10-01

When Herbert Kroemer stated in his Nobel address [1] that ``the interface is the device,'' he was implicitly acknowledging the importance of understanding the physics of interfaces. If interfaces are to have character traits, then ``impedance'' (or complex capacitance) would be a commonly used descriptor. In this talk I will discuss the use of magnetic fields to probe the ``character'' of a variety of interfaces including planar capacitor structures with magnetic electrodes, simple metal/semiconductor contacts (Schottky barriers) and the interface-dominated competition on microscopic length scales between ferromagnetic metallic and charge-ordered insulating phases in complex oxides. I will show that seeking experimental answers to surprisingly simple questions often leads to striking results that seriously challenge theoretical understanding. Perhaps Herbert Kroemer should have said, ``the interface is the device with a magnetic personality that continually surprises.'' [3pt] [1] Herbert Kroemer, ``Quasielectric fields and band offsets: teaching electron s new tricks,'' Nobel Lecture, December 8, 2000:

Theoretical investigation of magnetic properties in interfaces of magnetic nanoparticles and amorphous carbons

NASA Astrophysics Data System (ADS)

Sun, Shih-Jye; Hsu, Hua-Shu; Ovchinnikov, Sergei; Chen, Guan-Long

2017-06-01

Based on the experimental finding of the exchange bias in amorphous carbon samples with embedded Co nanoparticles and on the graphited character of the amorphous carbon interface confirmed by molecular dynamics simulations we have proposed the interface of graphited carbon to be antiferromagnetic. A theoretical model, which comprises the Kondo interactions in the interfaces of Co nanoparticles and the induced antiferromagnetic interactions in the graphited carbons, is employed to evaluate the ferromagnetism of the interfaces of Co nanoparticles. We have shown that the ferromagnetism of interfaces of Co nanoparticles will be enhanced by the increase of antiferromagnetic interaction as well as the increase of electron density in the graphited carbons. In particular, we found that the antiferromagnetic interactions in graphited carbons will change the spin-wave excitation in interfaces of Co nanoparticles from the quasiacoustic mode to the quasioptical one.

An implementation and evaluation of the MPI 3.0 one-sided communication interface

DOE PAGES

Dinan, James S.; Balaji, Pavan; Buntinas, Darius T.; ...

2016-01-09

The Q1 Message Passing Interface (MPI) 3.0 standard includes a significant revision to MPI’s remote memory access (RMA) interface, which provides support for one-sided communication. MPI-3 RMA is expected to greatly enhance the usability and performance ofMPI RMA.We present the first complete implementation of MPI-3 RMA and document implementation techniques and performance optimization opportunities enabled by the new interface. Our implementation targets messaging-based networks and is publicly available in the latest release of the MPICH MPI implementation. Here using this implementation, we explore the performance impact of new MPI-3 functionality and semantics. Results indicate that the MPI-3 RMA interface providesmore » significant advantages over the MPI-2 interface by enabling increased communication concurrency through relaxed semantics in the interface and additional routines that provide new window types, synchronization modes, and atomic operations.« less

An implementation and evaluation of the MPI 3.0 one-sided communication interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dinan, James S.; Balaji, Pavan; Buntinas, Darius T.

The Q1 Message Passing Interface (MPI) 3.0 standard includes a significant revision to MPI’s remote memory access (RMA) interface, which provides support for one-sided communication. MPI-3 RMA is expected to greatly enhance the usability and performance ofMPI RMA.We present the first complete implementation of MPI-3 RMA and document implementation techniques and performance optimization opportunities enabled by the new interface. Our implementation targets messaging-based networks and is publicly available in the latest release of the MPICH MPI implementation. Here using this implementation, we explore the performance impact of new MPI-3 functionality and semantics. Results indicate that the MPI-3 RMA interface providesmore » significant advantages over the MPI-2 interface by enabling increased communication concurrency through relaxed semantics in the interface and additional routines that provide new window types, synchronization modes, and atomic operations.« less

Experimental metrology to obtain thermal phonon transmission coefficients at solid interfaces

DOE PAGES

Hua, Chengyun; Chen, Xiangwen; Ravichandran, Navaneetha K.; ...

2017-05-17

Interfaces play an essential role in phonon-mediated heat conduction in solids, impacting applications ranging from thermoelectric waste heat recovery to heat dissipation in electronics. From the microscopic perspective, interfacial phonon transport is described by transmission coefficients that link vibrational modes in the materials composing the interface. But, direct experimental determination of these coefficients is challenging because most experiments provide a mode-averaged interface conductance that obscures the microscopic detail. Here, we report a metrology to extract thermal phonon transmission coefficients at solid interfaces using ab initio phonon transport modeling and a thermal characterization technique, time-domain thermoreflectance. In combination with transmission electronmore » microscopy characterization of the interface, our approach allows us to link the atomic structure of an interface to the spectral content of the heat crossing it. This work provides a useful perspective on the microscopic processes governing interfacial heat conduction.« less

Microstructure Evolution and Failure Analysis of an Aluminum-Copper Cathode Conductive Head Produced by Explosive Welding

NASA Astrophysics Data System (ADS)

Wei, Yanni; Luo, Yongguang; Qu, Hongtao; Zou, Juntao; Liang, Shuhua

2017-12-01

In this paper, microstructure evolution and failure analysis of the aluminum-copper interface of cathode conductive heads during their use were studied. The interface morphologies, compositions, conductivity and mechanical properties were investigated and analyzed. Obvious corrosion was found on the surface of the contact interface, which was more prevalent on an Al matrix. The crack increased sharply in the local metallurgical bonding areas on the interface, with the compound volume having no significant change. The phase transformation occurred on the interface during use, which was investigated using the elemental composition and x-ray diffraction pattern. The microhardness near the interface increased accordingly. An obvious electrical conductivity decrease appeared on the Al/Cu interface of the cathode conductive head after use over a specific time interval. Therefore, the deterioration of the microstructures and corrosion are the primary factors that affect the electrical conductivity and effective bonding, which will lead to eventual failure.

Interaction of intermetallic compound formation in Cu/SnAgCu/NiAu sandwich solder joints

NASA Astrophysics Data System (ADS)

Xia, Yanghua; Lu, Chuanyan; Chang, Junling; Xie, Xiaoming

2006-05-01

The interaction between Cu/solder interface and solder/Ni interface at a Cu/SnAgCu/NiAu sandwich solder joint with various surface finishes and solder heights was investigated. The interfacial microstructure and composition of intermetallic compounds (IMCs) were characterized by a scanning electron microscope (SEM) equipped with energy-dispersive x-ray spectroscopy (EDX). The phase structure of IMC was identified by x-ray diffraction (XRD). It is found that ternary (Cu,Ni)6Sn5 IMCs form at both interfaces. The composition, thickness, and morphology of the ternary IMCs depend not only on the interface itself, but also on the opposite interface. That is to say, strong coupling effects exist between the two interfaces. Lattice parameters of (Cu,Ni)6Sn5 shrink with increasing Ni content, in agreement with Vegard’s law. The mechanism of ternary IMC formation and interface coupling effects are discussed in this paper.

Network device interface for digitally interfacing data channels to a controller a via network

NASA Technical Reports Server (NTRS)

Konz, Daniel W. (Inventor); Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Winkelmann, Joseph P. (Inventor)

2006-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. In one embodiment, the bus controller transmits messages to the network device interface containing a plurality of bits having a value defined by a transition between first and second states in the bits. The network device interface determines timing of the data sequence of the message and uses the determined timing to communicate with the bus controller.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

2005-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface uses a specialized protocol for communicating across the network bus that uses a low-level instruction set and has low overhead for data communication.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor); Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor)

2007-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is converted into digital signals and transmitted to the controller. In some embodiments, network device interfaces associated with different data channels coordinate communications with the other interfaces based on either a transition in a command message sent by the bus controller or a synchronous clock signal.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Ellerbrock, Philip J. (Inventor); Winkelmann, Joseph P. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor)

2006-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface is a state machine, such as an ASIC, that operates independent of a processor in communicating with the bus controller and data channels.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Ellerbrock, Philip J. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor); Grant, Robert L. (Inventor)

2004-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface uses a specialized protocol for communicating across the network bus that uses a low-level instruction set and has low overhead for data communication.

User interface for a tele-operated robotic hand system

DOEpatents

Crawford, Anthony L

2015-03-24

Disclosed here is a user interface for a robotic hand. The user interface anchors a user's palm in a relatively stationary position and determines various angles of interest necessary for a user's finger to achieve a specific fingertip location. The user interface additionally conducts a calibration procedure to determine the user's applicable physiological dimensions. The user interface uses the applicable physiological dimensions and the specific fingertip location, and treats the user's finger as a two link three degree-of-freedom serial linkage in order to determine the angles of interest. The user interface communicates the angles of interest to a gripping-type end effector which closely mimics the range of motion and proportions of a human hand. The user interface requires minimal contact with the operator and provides distinct advantages in terms of available dexterity, work space flexibility, and adaptability to different users.

Impact of process temperature on GaSb metal-oxide-semiconductor interface properties fabricated by ex-situ process

NASA Astrophysics Data System (ADS)

Yokoyama, Masafumi; Asakura, Yuji; Yokoyama, Haruki; Takenaka, Mitsuru; Takagi, Shinichi

2014-06-01

We have studied the impact of process temperature on interface properties of GaSb metal-oxide-semiconductor (MOS) structures fabricated by an ex-situ atomic-layer-deposition (ALD) process. We have found that the ALD temperature strongly affects the Al2O3/GaSb MOS interface properties. The Al2O3/GaSb MOS interfaces fabricated at the low ALD temperature of 150 °C have the minimum interface-trap density (Dit) of ˜4.5 × 1013 cm-2 eV-1. We have also found that the post-metalization annealing at temperature higher than 200 °C degrades the Al2O3/GaSb MOS interface properties. The low-temperature process is preferable in fabricating GaSb MOS interfaces in the ex-situ ALD process to avoid the high-temperature-induced degradations.

Creating and optimizing interfaces for electric-field and photon-induced charge transfer.

PubMed

Park, Byoungnam; Whitham, Kevin; Cho, Jiung; Reichmanis, Elsa

2012-11-27

We create and optimize a structurally well-defined electron donor-acceptor planar heterojunction interface in which electric-field and/or photon-induced charge transfer occurs. Electric-field-induced charge transfer in the dark and exciton dissociation at a pentacene/PCBM interface were probed by in situ thickness-dependent threshold voltage shift measurements in field-effect transistor devices during the formation of the interface. Electric-field-induced charge transfer at the interface in the dark is correlated with development of the pentacene accumulation layer close to PCBM, that is, including interface area, and dielectric relaxation time in PCBM. Further, we demonstrate an in situ test structure that allows probing of both exciton diffusion length and charge transport properties, crucial for optimizing optoelectronic devices. Competition between the optical absorption length and the exciton diffusion length in pentacene governs exciton dissociation at the interface. Charge transfer mechanisms in the dark and under illumination are detailed.

Interface Engineering for Nanoelectronics.

PubMed

Hacker, C A; Bruce, R C; Pookpanratana, S J

2017-01-01

Innovation in the electronics industry is tied to interface engineering as devices increasingly incorporate new materials and shrink. Molecular layers offer a versatile means of tuning interfacial electronic, chemical, physical, and magnetic properties enabled by a wide variety of molecules available. This paper will describe three instances where we manipulate molecular interfaces with a specific focus on the nanometer scale characterization and the impact on the resulting performance. The three primary themes include, 1-designer interfaces, 2-electronic junction formation, and 3-advancing metrology for nanoelectronics. We show the ability to engineer interfaces through a variety of techniques and demonstrate the impact on technologies such as molecular memory and spin injection for organic electronics. Underpinning the successful modification of interfaces is the ability to accurately characterize the chemical and electronic properties and we will highlight some measurement advances key to our understanding of the interface engineering for nanoelectronics.

Interface Engineering for Nanoelectronics

PubMed Central

Hacker, C. A.; Bruce, R. C.; Pookpanratana, S. J.

2017-01-01

Innovation in the electronics industry is tied to interface engineering as devices increasingly incorporate new materials and shrink. Molecular layers offer a versatile means of tuning interfacial electronic, chemical, physical, and magnetic properties enabled by a wide variety of molecules available. This paper will describe three instances where we manipulate molecular interfaces with a specific focus on the nanometer scale characterization and the impact on the resulting performance. The three primary themes include, 1-designer interfaces, 2-electronic junction formation, and 3-advancing metrology for nanoelectronics. We show the ability to engineer interfaces through a variety of techniques and demonstrate the impact on technologies such as molecular memory and spin injection for organic electronics. Underpinning the successful modification of interfaces is the ability to accurately characterize the chemical and electronic properties and we will highlight some measurement advances key to our understanding of the interface engineering for nanoelectronics. PMID:29276553

Cognitive Task Analysis, Interface Design, and Technical Troubleshooting.

ERIC Educational Resources Information Center

Steinberg, Linda S.; Gitomer, Drew H.

A model of the interface design process is proposed that makes use of two interdependent levels of cognitive analysis: the study of the criterion task through an analysis of expert/novice differences and the evaluation of the working user interface design through the application of a practical interface analysis methodology (GOMS model). This dual…

Representing Graphical User Interfaces with Sound: A Review of Approaches

ERIC Educational Resources Information Center

Ratanasit, Dan; Moore, Melody M.

2005-01-01

The inability of computer users who are visually impaired to access graphical user interfaces (GUIs) has led researchers to propose approaches for adapting GUIs to auditory interfaces, with the goal of providing access for visually impaired people. This article outlines the issues involved in nonvisual access to graphical user interfaces, reviews…

CDROM User Interface Evaluation: The Appropriateness of GUIs.

ERIC Educational Resources Information Center

Bosch, Victoria Manglano; Hancock-Beaulieu, Micheline

1995-01-01

Assesses the appropriateness of GUIs (graphical user interfaces), more specifically Windows-based interfaces for CD-ROM. An evaluation model is described that was developed to carry out an expert evaluation of the interfaces of seven CD-ROM products. Results are discussed in light of HCI (human-computer interaction) usability criteria and design…

Symmetry-Driven Atomic Rearrangement at a Brownmillerite-Perovskite Interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, Tricia L.; Jeen, Hyoungjeen; Gao, Xiang

2015-12-15

To those investigating new interfacial phenomena, symmetry mismatch is of immense interest. The interfacial and bulk microstructure of the brownmillerite–perovskite interface is probed using detailed transmission electron microscopy. Unique asymmetric displacements of the tetrahedra at the interface are observed, signifying a compensation mechanism for lattice and symmetry mismatch at the interface.

Thermal Interface Comparisons Under Flight Like Conditions

NASA Technical Reports Server (NTRS)

Rodriquez-Ruiz, Juan

2008-01-01

Thermal interface materials are used in bolted interfaces to promote good thermal conduction between the two. The mounting surface can include panels, heat pipes, electronics boxes, etc.. . On Lunar Reconnaissance Orbiter (LRO) project the results are directly applicable: a) Several high power avionics boxes b) Several interfaces from RWA to radiator through heat pipe network

Cross-Cultural Interface Design and the Classroom-Learning Environment in Taiwan

ERIC Educational Resources Information Center

Chang, Chia-Lin; Su, Yelin

2012-01-01

This study examined whether using localized interface designs would make a difference in users' learning results and their perceptions of the interface design in a classroom learning environment. This study also sought to learn more about users' attitudes toward the localized interface features. To assess the impact of using localized interfaces…

Joint Service Aircrew Mask (JSAM) Rotary Wing (RW): MPU-5 Noise Attenuation Performance

DTIC Science & Technology

2016-06-09

Swayne Ball Aerospace and Technologies Corp. Dayton, OH Hilary Gallagher Warfighter Interface Division Battlespace Acoustics Branch Wright... Acoustics Branch Battlespace Acoustics Branch Warfighter Interface Division //signed// WILLIAM E. RUSSELL Chief, Warfighter Interface...Directorate Warfighter Interface Division Battlespace Acoustics Branch Wright-Patterson AFB OH 45433 711 HPW/RHCB 11. SPONSOR

Film bonded fuel cell interface configuration

DOEpatents

Kaufman, Arthur; Terry, Peter L.

1985-01-01

An improved interface configuration for use between adjacent elements of a fuel cell stack. The interface is impervious to gas and liquid and provides resistance to corrosion by the electrolyte of the fuel cell. A multi-layer arrangement for the interface provides bridging electrical contact with a hot-pressed resin filling the void space.

Process for making film-bonded fuel cell interfaces

DOEpatents

Kaufman, Arthur; Terry, Peter L.

1990-07-03

An improved interface configuration for use between adjacent elements of a fuel cell stack. The interface is impervious to gas and liquid and provides resistance to corrosion by the electrolyte of the fuel cell. A multi-layer arrangement for the interface provides bridging electrical contact with a hot-pressed resin filling the void space.

A Finite Element Method for Simulation of Compressible Cavitating Flows

NASA Astrophysics Data System (ADS)

Shams, Ehsan; Yang, Fan; Zhang, Yu; Sahni, Onkar; Shephard, Mark; Oberai, Assad

2016-11-01

This work focuses on a novel approach for finite element simulations of multi-phase flows which involve evolving interface with phase change. Modeling problems, such as cavitation, requires addressing multiple challenges, including compressibility of the vapor phase, interface physics caused by mass, momentum and energy fluxes. We have developed a mathematically consistent and robust computational approach to address these problems. We use stabilized finite element methods on unstructured meshes to solve for the compressible Navier-Stokes equations. Arbitrary Lagrangian-Eulerian formulation is used to handle the interface motions. Our method uses a mesh adaptation strategy to preserve the quality of the volumetric mesh, while the interface mesh moves along with the interface. The interface jump conditions are accurately represented using a discontinuous Galerkin method on the conservation laws. Condensation and evaporation rates at the interface are thermodynamically modeled to determine the interface velocity. We will present initial results on bubble cavitation the behavior of an attached cavitation zone in a separated boundary layer. We acknowledge the support from Army Research Office (ARO) under ARO Grant W911NF-14-1-0301.

A validated methodology for determination of laboratory instrument computer interface efficacy

NASA Astrophysics Data System (ADS)

1984-12-01

This report is intended to provide a methodology for determining when, and for which instruments, direct interfacing of laboratory instrument and laboratory computers is beneficial. This methodology has been developed to assist the Tri-Service Medical Information Systems Program Office in making future decisions regarding laboratory instrument interfaces. We have calculated the time savings required to reach a break-even point for a range of instrument interface prices and corresponding average annual costs. The break-even analyses used empirical data to estimate the number of data points run per day that are required to meet the break-even point. The results indicate, for example, that at a purchase price of $3,000, an instrument interface will be cost-effective if the instrument is utilized for at least 154 data points per day if operated in the continuous mode, or 216 points per day if operated in the discrete mode. Although this model can help to ensure that instrument interfaces are cost effective, additional information should be considered in making the interface decisions. A reduction in results transcription errors may be a major benefit of instrument interfacing.

The simulation study of protein-protein interfaces based on the 4-helix bundle structure

NASA Astrophysics Data System (ADS)

Fukuda, Masaki; Komatsu, Yu; Morikawa, Ryota; Miyakawa, Takeshi; Takasu, Masako; Akanuma, Satoshi; Yamagishi, Akihiko

2013-02-01

Docking of two protein molecules is induced by intermolecular interactions. Our purposes in this study are: designing binding interfaces on the two proteins, which specifically interact to each other; and inducing intermolecular interactions between the two proteins by mixing them. A 4-helix bundle structure was chosen as a scaffold on which binding interfaces were created. Based on this scaffold, we designed binding interfaces involving charged and nonpolar amino acid residues. We performed molecular dynamics (MD) simulation to identify suitable amino acid residues for the interfaces. We chose YciF protein as the scaffold for the protein-protein docking simulation. We observed the structure of two YciF protein molecules (I and II), and we calculated the distance between centroids (center of gravity) of the interfaces' surface planes of the molecules I and II. We found that the docking of the two protein molecules can be controlled by the number of hydrophobic and charged amino acid residues involved in the interfaces. Existence of six hydrophobic and five charged amino acid residues within an interface were most suitable for the protein-protein docking.

User interface customization on Endoscopy Department Mini-PACS and its impact on examination workflow

NASA Astrophysics Data System (ADS)

Osada, Masakazu; Kaise, Mitsuru; Ozeki, Takeshi; Tsunakawa, Hirofumi; Tsunakawa, Kiyoshi; Takayanagi, Takashi; Suzuki, Nobuaki; Miwa, Jun; Ohta, Yasuhiko; Kanai, Koichi

1999-07-01

We have proposed a new user interface with workflow customization, implemented and evaluted in Endoscopy Department Mini-PACS that has been introduced and routinely used for two years at Toshiba General Hospital. We have set some task at endoscopy image acquisition units during examinations for two different types of user interfaces and compared performance. One is a command-button based operation using a remote control, and another is that with eight graphic buttons which are displayed on a CRT monitor and can be customized. Results of the two-year study show that mean number of input diagnosis codes per examination with graphic and customized interface is significantly greater than that with conventional interface. Also, mean time to complete one upper gastric endoscopy examination with new user interface is about 17 percent less than that with conventional interface. These result suggest that systems with the visualized and customized operation and feedback encourages physicians to use more functions and to compete tasks more efficiently than systems with conventional command-button based user interfaces.

TangibleCubes — Implementation of Tangible User Interfaces through the Usage of Microcontroller and Sensor Technology

NASA Astrophysics Data System (ADS)

Setscheny, Stephan

The interaction between human beings and technology builds a central aspect in human life. The most common form of this human-technology interface is the graphical user interface which is controlled through the mouse and the keyboard. In consequence of continuous miniaturization and the increasing performance of microcontrollers and sensors for the detection of human interactions, developers receive new possibilities for realising innovative interfaces. As far as this movement is concerned, the relevance of computers in the common sense and graphical user interfaces is decreasing. Especially in the area of ubiquitous computing and the interaction through tangible user interfaces a highly impact of this technical evolution can be seen. Apart from this, tangible and experience able interaction offers users the possibility of an interactive and intuitive method for controlling technical objects. The implementation of microcontrollers for control functions and sensors enables the realisation of these experience able interfaces. Besides the theories about tangible user interfaces, the consideration about sensors and the Arduino platform builds a main aspect of this work.