Global statistics of microphysical properties of cloud-top ice crystals

NASA Astrophysics Data System (ADS)

van Diedenhoven, B.; Fridlind, A. M.; Cairns, B.; Ackerman, A. S.; Riedi, J.

2017-12-01

Ice crystals in clouds are highly complex. Their sizes, macroscale shape (i.e., habit), mesoscale shape (i.e., aspect ratio of components) and microscale shape (i.e., surface roughness) determine optical properties and affect physical properties such as fall speeds, growth rates and aggregation efficiency. Our current understanding on the formation and evolution of ice crystals under various conditions can be considered poor. Commonly, ice crystal size and shape are related to ambient temperature and humidity, but global observational statistics on the variation of ice crystal size and particularly shape have not been available. Here we show results of a project aiming to infer ice crystal size, shape and scattering properties from a combination of MODIS measurements and POLDER-PARASOL multi-angle polarimetry. The shape retrieval procedure infers the mean aspect ratios of components of ice crystals and the mean microscale surface roughness levels, which are quantifiable parameters that mostly affect the scattering properties, in contrast to "habit". We present global statistics on the variation of ice effective radius, component aspect ratio, microscale surface roughness and scattering asymmetry parameter as a function of cloud top temperature, latitude, location, cloud type, season, etc. Generally, with increasing height, sizes decrease, roughness increases, asymmetry parameters decrease and aspect ratios increase towards unity. Some systematic differences are observed for clouds warmer and colder than the homogeneous freezing level. Uncertainties in the retrievals will be discussed. These statistics can be used as observational targets for modeling efforts and to better constrain other satellite remote sensing applications and their uncertainties.

Global Statistics of Microphysical Properties of Cloud-Top Ice Crystals

NASA Technical Reports Server (NTRS)

Van Diedenhoven, Bastiaan; Fridlind, Ann; Cairns, Brian; Ackerman, Andrew; Riedl, Jerome

2017-01-01

Ice crystals in clouds are highly complex. Their sizes, macroscale shape (i.e., habit), mesoscale shape (i.e., aspect ratio of components) and microscale shape (i.e., surface roughness) determine optical properties and affect physical properties such as fall speeds, growth rates and aggregation efficiency. Our current understanding on the formation and evolution of ice crystals under various conditions can be considered poor. Commonly, ice crystal size and shape are related to ambient temperature and humidity, but global observational statistics on the variation of ice crystal size and particularly shape have not been available. Here we show results of a project aiming to infer ice crystal size, shape and scattering properties from a combination of MODIS measurements and POLDER-PARASOL multi-angle polarimetry. The shape retrieval procedure infers the mean aspect ratios of components of ice crystals and the mean microscale surface roughness levels, which are quantifiable parameters that mostly affect the scattering properties, in contrast to a habit. We present global statistics on the variation of ice effective radius, component aspect ratio, microscale surface roughness and scattering asymmetry parameter as a function of cloud top temperature, latitude, location, cloud type, season, etc. Generally, with increasing height, sizes decrease, roughness increases, asymmetry parameters decrease and aspect ratios increase towards unity. Some systematic differences are observed for clouds warmer and colder than the homogeneous freezing level. Uncertainties in the retrievals will be discussed. These statistics can be used as observational targets for modeling efforts and to better constrain other satellite remote sensing applications and their uncertainties.

Experimental Evidence for Hydrogen Tunneling when the Isotopic Arrhenius Prefactor (AH/AD) is Unity

PubMed Central

Sharma, Sudhir C.; Klinman, Judith P.

2009-01-01

The temperature dependence of the kinetic isotope effect (KIE) is one of the major tools used for the investigation of hydrogen tunneling in condensed phase. Hydrogen transfer reactions displaying isotopic Arrhenius prefactor ratios (AH/AD) of unity are generally ascribed to a semi-classical mechanism. Here, we have identified a double mutant of soybean lipoxygenase (SLO-1, an enzyme previously shown to follow quantum mechanical hydrogen tunneling), that displays an AH/AD of unity and highly elevated (non-classical) KIEs. This observation highlights the shortcoming of assigning a hydrogen transfer reaction to a semi-classical model based solely on an Arrhenius prefactor ratio. PMID:19061319

Abdus Salam

NASA Astrophysics Data System (ADS)

Ziman, John

Mr. Vice-Chancellor Only connect! That is the theme that runs through the life and work of Abdus Salam. He has followed the teaching of Islam and has dedicated his life to the principle of unity — the unity of Nature and the unity of Mankind. As a natural philosopher he has seen that the various interactions of the elementary particles must be no more than diverse aspects of a single primary force. As a political and moral leader he has demonstrated that the various interactions of nations and cultures are no obstacle to the brotherhood of Man in science…

Multiple Dimensions of Teacher Identity Development from Pre-Service to Early Years of Teaching: A Longitudinal Study

ERIC Educational Resources Information Center

Hong, Ji; Greene, Barbara; Lowery, Jennifer

2017-01-01

Based on dialogical self theory framework that highlights three dimensions of identity construction (multiplicity vs. unity; social vs. individual; discontinuity vs. continuity), this study explored multiple aspects of teacher identity development over time, in relation to the unity of self, the way the social environment is negotiated, and the…

Large-eddy simulation of pollutant dispersion from a ground-level area source over urban street canyons with irreversible chemical reactions

NASA Astrophysics Data System (ADS)

Du, T. Z.; Liu, C.-H.; Zhao, Y. B.

2014-10-01

In this study, the dispersion of chemically reactive pollutants is calculated by large-eddy simulation (LES) in a neutrally stratified urban canopy layer (UCL) over urban areas. As a pilot attempt, idealized street canyons of unity building-height-to-street-width (aspect) ratio are used. Nitric oxide (NO) is emitted from the ground surface of the first street canyon into the domain doped with ozone (O3). In the absence of ultraviolet radiation, this irreversible chemistry produces nitrogen dioxide (NO2), developing a reactive plume over the rough urban surface. A range of timescales of turbulence and chemistry are utilized to examine the mechanism of turbulent mixing and chemical reactions in the UCL. The Damköhler number (Da) and the reaction rate (r) are analyzed along the vertical direction on the plane normal to the prevailing flow at 10 m after the source. The maximum reaction rate peaks at an elevation where Damköhler number Da is equal or close to unity. Hence, comparable timescales of turbulence and reaction could enhance the chemical reactions in the plume.

Jets or vortices - what flows are generated by an inverse turbulent cascade?

NASA Astrophysics Data System (ADS)

Frishman, Anna; Laurie, Jason; Falkovich, Gregory

An inverse cascade-energy transfer to progressively larger scales - is a salient feature of two-dimensional turbulence. If the cascade reaches the system scale, it creates a coherent flow expected to have the largest available scale and conform with the symmetries of the domain. In a doubly periodic rectangle, the mean flow with zero total momentum was therefore believed to be unidirectional, with two jets along the short side; while for an aspect ratio close to unity, a vortex dipole was expected. Using direct numerical simulations, we show that in fact neither the box symmetry is respected nor the largest scale is realized: the flow is never purely unidirectional since the inverse cascade produces coherent vortices, whose number and relative motion are determined by the aspect ratio. This spontaneous symmetry breaking is closely related to the hierarchy of averaging times. Long-time averaging restores translational invariance due to vortex wandering along one direction, and gives jets whose profile, however, can be deduced neither from the largest-available-scale argument, nor from the often employed maximum-entropy principle or quasi-linear approximation.

Jets or vortices—What flows are generated by an inverse turbulent cascade?

NASA Astrophysics Data System (ADS)

Frishman, Anna; Laurie, Jason; Falkovich, Gregory

2017-03-01

An inverse cascade, energy transfer to progressively larger scales, is a salient feature of two-dimensional turbulence. If the cascade reaches the system scale, it creates a coherent flow expected to have the largest available scale and conform with the symmetries of the domain. In a doubly periodic rectangle, the mean flow with zero total momentum was therefore believed to be unidirectional, with two jets along the short side; while for an aspect ratio close to unity, a vortex dipole is expected. Using direct numerical simulations, we show that in fact neither is the box symmetry respected nor the largest scale realized: the flow is never purely unidirectional since the inverse cascade produces coherent vortices, whose number and relative motion are determined by the aspect ratio. This spontaneous symmetry breaking is closely related to the hierarchy of averaging times. Long-time averaging restores translational invariance due to vortex wandering along one direction, and gives jets whose profile, however, can neither be deduced from the largest-available-scale argument, nor from the often employed maximum-entropy principle or quasilinear approximation.

Assessment of densification and mechanical property of AISI 8630 steel composition on different heat treatments produced through hot upsetting powder preform forging

NASA Astrophysics Data System (ADS)

Bala, Y. G.; Sankaranarayanan, S. Raman; Pandey, K. S.

2015-11-01

The present investigation was carried out to evaluate the densification, mechanical properties, microstructural and fractrography effects of AISI 8630 steel composition developed through powder preform forging under different heat treated conditions. Sintered preforms of different aspect ratios such as 0.6, 0.9, and 1.2 were hot upset forged to disc shape to different height strain to analysis the densification mechanism. Certain relationships relating strains, Poisson's ratio relating densification have revealed the effect of preform geometry on densification kinetics and resulted in the polynomial expression with justified regression coefficient greater the 0.9 or unity. The preforms of aspect ratio of 1.1 were hot upset forged to square cross section bars and transferred to different quenching medium like oil, water, furnace and air to assess its mechanical properties. Comparing the temperament of the heat treatments, sintered forged homogenised water quenched sample upshot in the maximum Tensile strength with least per centage elongation andthe furnace cooled sample shows the maximum toughness with desirable per centage elongation and least tensile strength. Microstructure stated the presence of varying ferrite and pearlite distribution and fractograph studies has disclosed the mixed mode of failure on the effect of varying heat treatments progression has affected the properties significantly.

Shear-induced orientational dynamics and spatial heterogeneity in suspensions of motile phytoplankton

PubMed Central

Barry, Michael T.; Rusconi, Roberto; Guasto, Jeffrey S.; Stocker, Roman

2015-01-01

Fluid flow, ubiquitous in natural and man-made environments, has the potential to profoundly impact the transport of microorganisms, including phytoplankton in aquatic habitats and bioreactors. Yet, the effect of ambient flow on the swimming behaviour of phytoplankton has remained poorly understood, largely owing to the difficulty of observing cell–flow interactions at the microscale. Here, we present microfluidic experiments where we tracked individual cells for four species of motile phytoplankton exposed to a spatially non-uniform fluid shear rate, characteristic of many flows in natural and artificial environments. We observed that medium-to-high mean shear rates (1–25 s−1) produce heterogeneous cell concentrations in the form of regions of accumulation and regions of depletion. The location of these regions relative to the flow depends on the cells' propulsion mechanism, body shape and flagellar arrangement, as captured by an effective aspect ratio. Species having a large effective aspect ratio accumulated in the high-shear regions, owing to shear-induced alignment of the swimming orientation with the fluid streamlines. Species having an effective aspect ratio close to unity exhibited little preferential accumulation at low-to-moderate flow rates, but strongly accumulated in the low-shear regions under high flow conditions, potentially owing to an active, behavioural response of cells to shear. These observations demonstrate that ambient fluid flow can strongly affect the motility and spatial distribution of phytoplankton and highlight the rich dynamics emerging from the interaction between motility, morphology and flow. PMID:26538558

A fundamental study of drag and an assessment of conventional drag-due-to-lift reduction devices

NASA Astrophysics Data System (ADS)

Yates, J. E.; Donald, C. D.

1986-09-01

The integral conservation laws of fluid mechanics are used to assess the drag efficiency of lifting wings, both CTOL and various out-of-plane configurations. The drag-due-to-lift is separated into two major components: (1) the induced drag-due-to-lift that depends on aspect ratio but is relatively independent of Reynolds number; (2) the form drag-due-to-lift that is independent of aspect ratio but dependent on the details of the wing section design, planform and Reynolds number. For each lifting configuration there is an optimal load distribution that yields the minimum value of drag-due-to-lift. For well designed high aspect ratio CTOL wings the two drag components are independent. With modern design technology CTOL wings can be (and usually are) designed with a drag-due-to-lift efficiency close to unity. Wing tip-devices (winglets, feathers, sails, etc.) can improve drag-due-to-lift efficiency by 10 to 15% if they are designed as an integral part of the wing. As add-on devices they can be detrimental. It is estimated that 25% improvements of wing drag-due-to-lift efficiency can be obtained with joined tip configurations and vertically separated lifting elements without considering additional benefits that might be realized by improved structural efficiency. It is strongly recommended that an integrated aerodynamic/structural approach be taken in the design of (or research on) future out-of-plane configurations.

A fundamental study of drag and an assessment of conventional drag-due-to-lift reduction devices

NASA Technical Reports Server (NTRS)

Yates, J. E.; Donald, C. D.

1986-01-01

The integral conservation laws of fluid mechanics are used to assess the drag efficiency of lifting wings, both CTOL and various out-of-plane configurations. The drag-due-to-lift is separated into two major components: (1) the induced drag-due-to-lift that depends on aspect ratio but is relatively independent of Reynolds number; (2) the form drag-due-to-lift that is independent of aspect ratio but dependent on the details of the wing section design, planform and Reynolds number. For each lifting configuration there is an optimal load distribution that yields the minimum value of drag-due-to-lift. For well designed high aspect ratio CTOL wings the two drag components are independent. With modern design technology CTOL wings can be (and usually are) designed with a drag-due-to-lift efficiency close to unity. Wing tip-devices (winglets, feathers, sails, etc.) can improve drag-due-to-lift efficiency by 10 to 15% if they are designed as an integral part of the wing. As add-on devices they can be detrimental. It is estimated that 25% improvements of wing drag-due-to-lift efficiency can be obtained with joined tip configurations and vertically separated lifting elements without considering additional benefits that might be realized by improved structural efficiency. It is strongly recommended that an integrated aerodynamic/structural approach be taken in the design of (or research on) future out-of-plane configurations.

Organic unity theory: an integrative mind-body theory for psychiatry.

PubMed

Goodman, A

1997-12-01

The potential of psychiatry as an integrative science has been impeded by an internal schism that derives from the duality of mental and physical. Organic unity theory is proposed as a conceptual framework that brings together the terms of the mind-body duality in one coherent perspective. Organic unity theory is braided of three strands: identity, which describes the relationship between mentally described events and corresponding physically described events; continuity, which describes the linguistic-conceptual system that contains both mental and physical terms; and dialectic, which describes the relationship between the empirical way of knowing that is associated with the physical domain of the linguistic-conceptual system and the hermeneutic way of knowing that is associated with the mental domain. Each strand represents an integrative formulation that resolves an aspect of mental-physical dualism into an underlying unity. After the theory is presented, its implications for psychiatry are briefly considered.

Carbonaceous composition changes of heavy-duty diesel engine particles in relation to biodiesels, aftertreatments and engine loads.

PubMed

Cheng, Man-Ting; Chen, Hsun-Jung; Young, Li-Hao; Yang, Hsi-Hsien; Tsai, Ying I; Wang, Lin-Chi; Lu, Jau-Huai; Chen, Chung-Bang

2015-10-30

Three biodiesels and two aftertreatments were tested on a heavy-duty diesel engine under the US FTP transient cycle and additional four steady engine loads. The objective was to examine their effects on the gaseous and particulate emissions, with emphasis given to the organic and elemental carbon (OC and EC) in the total particulate matter. Negligible differences were observed between the low-sulfur (B1S50) and ultralow-sulfur (B1S10) biodiesels, whereas small reductions of OC were identified with the 10% biodiesel blend (B10). The use of diesel oxidation catalyst (DOC1) showed moderate reductions of EC and particularly OC, resulting in the OC/EC ratio well below unity. The use of DOC plus diesel particulate filter (DOC2+DPF) yielded substantial reductions of OC and particularly EC, resulting in the OC/EC ratio well above unity. The OC/EC ratios were substantially above unity at idle and low load, whereas below unity at medium and high load. The above changes in particulate OC and EC are discussed with respect to the fuel content, pollutant removal mechanisms and engine combustion conditions. Overall, the present study shows that the carbonaceous composition of PM could change drastically with engine load and aftertreatments, and to a lesser extent with the biodiesels under study. Copyright © 2015 Elsevier B.V. All rights reserved.

Drag reduction using wrinkled surfaces in high Reynolds number laminar boundary layer flows

NASA Astrophysics Data System (ADS)

Raayai-Ardakani, Shabnam; McKinley, Gareth H.

2017-09-01

Inspired by the design of the ribbed structure of shark skin, passive drag reduction methods using stream-wise riblet surfaces have previously been developed and tested over a wide range of flow conditions. Such textures aligned in the flow direction have been shown to be able to reduce skin friction drag by 4%-8%. Here, we explore the effects of periodic sinusoidal riblet surfaces aligned in the flow direction (also known as a "wrinkled" texture) on the evolution of a laminar boundary layer flow. Using numerical analysis with the open source Computational Fluid Dynamics solver OpenFOAM, boundary layer flow over sinusoidal wrinkled plates with a range of wavelength to plate length ratios ( λ / L ), aspect ratios ( 2 A / λ ), and inlet velocities are examined. It is shown that in the laminar boundary layer regime, the riblets are able to retard the viscous flow inside the grooves creating a cushion of stagnant fluid that the high-speed fluid above can partially slide over, thus reducing the shear stress inside the grooves and the total integrated viscous drag force on the plate. Additionally, we explore how the boundary layer thickness, local average shear stress distribution, and total drag force on the wrinkled plate vary with the aspect ratio of the riblets as well as the length of the plate. We show that riblets with an aspect ratio of close to unity lead to the highest reduction in the total drag, and that because of the interplay between the local stress distribution on the plate and stream-wise evolution of the boundary layer the plate has to exceed a critical length to give a net decrease in the total drag force.

Evidence that the oxygen enhancement ratio for pink somatic mutations in Tradescantia stamen hairs may approach unity at very low x-ray doses

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

Underbrink, A.G.; Woch, B.

1980-11-01

Experimental evidence was found that the oxygen enhancement ratio (OER) for pink somatic mutations in the stamen hairs of Tradescantia clone 02 appears to reach unity at X-ray doses of 2 to 3 rad. There is also a small segment on the dose-response curves from about 3 to 10 rad where the OER appears to be dose-dependent. At higher doses the aerated and hypoxic curves are parallel, and the OER is 3.2 up to doses where the mutation frequency reaches a plateau.

Flame quenching by a variable-width rectangular-slot burner as a function of pressure for various propane-oxygen-nitrogen mixtures

NASA Technical Reports Server (NTRS)

Berlad, Abraham L

1954-01-01

Flame quenching by a variable-width rectangular-slot burner as a function of pressure for various propane-oxygen-nitrogen mixtures was investigated. It was found that for cold gas temperatures of 27 degrees C, pressures of 0.1 ro 1.0 atmosphere, and volumetric oxygen reactions of the oxidant of 0.17, 0.21, 0.30, 0.50, and 0.70, the relation between pressure p and quenching distance d is approximately given by d (unity) p (superscript -r) with r = 1, for equivalence ratios approximately equal to one. The quenching equation of Simon and Belles was tested. For equivalence ratios less than or equal to unity, this equation may by used, together with one empirical constant, to predict the observed quenching distance within 4.2 percent. The equation in it's present form does not appear to be suitable for values of the equivalence ratio greater than unity. A quantitative theoretical investigation has also been made of the error implicit in the assumption that flame quenching by plane parallel plates of infinite extent is equivalent to that of a rectangular burner. A curve is presented which relates the magnitude of this error to the length-to-width ratio of the rectangular burner.

Vibration energy harvesting using piezoelectric unimorph cantilevers with unequal piezoelectric and nonpiezoelectric lengths

PubMed Central

Gao, Xiaotong; Shih, Wei-Heng; Shih, Wan Y.

2010-01-01

We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced voltage which was important for charge storage for later use occurred with a PUC that had a nonpiezoelectric-to-piezoelectric length ratio greater than unity, whereas the maximum power when the PUC was connected to a resistor for immediate power consumption occurred at a unity nonpiezoelectric-to-piezoelectric length ratio. PMID:21200444

Vibration energy harvesting using piezoelectric unimorph cantilevers with unequal piezoelectric and nonpiezoelectric lengths.

PubMed

Gao, Xiaotong; Shih, Wei-Heng; Shih, Wan Y

2010-12-06

We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced voltage which was important for charge storage for later use occurred with a PUC that had a nonpiezoelectric-to-piezoelectric length ratio greater than unity, whereas the maximum power when the PUC was connected to a resistor for immediate power consumption occurred at a unity nonpiezoelectric-to-piezoelectric length ratio.

Heat Transfer in a Complex Trailing Edge Passage for a High Pressure Turbine Blade. Part 2:; Simulation Results

NASA Technical Reports Server (NTRS)

Rigby, David L.; Bunker, Ronald S.

2002-01-01

A combined experimental and numerical study to investigate the heat transfer distribution in a complex blade trailing edge passage was conducted. The geometry consists of a two pass serpentine passage with taper toward the trailing edge, as well as from hub to tip. The upflow channel has an average aspect ratio of roughly 14:1, while the exit passage aspect ratio is about 5:1. The upflow channel is split in an interrupted way and is smooth on the trailing edge side of the split and turbulated on the other side. A turning vane is placed near the tip of the upflow channel. Reynolds numbers in the range of 31,000 to 61,000, based on inlet conditions, were simulated numerically. The simulation was performed using the Glenn-HT code, a full three-dimensional Navier-Stokes solver using the Wilcox k-omega turbulence model. A structured multi-block grid is used with approximately 4.5 million cells and average y+ values on the order of unity. Pressure and heat transfer distributions are presented with comparison to the experimental data. While there are some regions with discrepancies, in general the agreement is very good for both pressure and heat transfer.

Effects of End CAP and Aspect Ratio on Transmission of Sound across a Truss-Like Periodic Double Panel

NASA Astrophysics Data System (ADS)

EL-RAHEB, M.; WAGNER, P.

2002-02-01

Transmission of sound across 2-D truss-like periodic double panels separated by an air gap and in contact with an acoustic fluid on the external faces is analyzed. Each panel is made of repeated cells. Combining the transfer matrices of the unit cell forms a set of equations for the overall elastic frequency response. The acoustic pressure in the fluids is expressed using a source boundary element method. Adding rigid reflecting end caps confines the air in the gap between panels which influences sound transmission. Measured values of transmission loss differ from the 2-D model by the wide low-frequency dip of the mass-spring-mass or “msm” resonance also termed the “air gap resonance”. In this case, the panels act as rigid masses and the air gap acts as an adiabatic air spring. Results from the idealized 3-D and 2-D models, incorporating rigid cavities and elastic plates, reveal that the “msm” dip is absent in 2-D models radiating into a semi-infinite medium. The dip strengthens as aspect ratio approaches unity. Even when the dip disappears in 2-D, TL rises more steeply for frequencies above the “msm” frequency.

Observations of electron phase-space holes driven during magnetic reconnection in a laboratory plasma

NASA Astrophysics Data System (ADS)

Fox, W.; Porkolab, M.; Egedal, J.; Katz, N.; Le, A.

2012-03-01

This work presents detailed experimental observations of electron phase-space holes driven during magnetic reconnection events on the Versatile Toroidal Facility. The holes are observed to travel on the order of or faster than the electron thermal speed, and are of large size scale, with diameter of order 60 Debye lengths. In addition, they have 3D spheroidal structure with approximately unity aspect ratio. We estimate the direct anomalous resistivity due to ion interaction with the holes and find it to be too small to affect the reconnection rate; however, the holes may play a role in reining in a tail of accelerated electrons and they indicate the presence of other processes in the reconnection layer, such as electron energization and electron beam formation.

On the Hypothesis of Control of the Universe

NASA Astrophysics Data System (ADS)

Kalanov, Temur Z.

2007-04-01

The problem of the SETI is not solved till now because idea of the SETI represents a methodological error in cosmology and astrophysics. This fact means that one should prove existence of Supreme Intelligence in a correct way. In this connection, the hypothesis of control of the Universe is proposed. The hypothesis is based on the new point of view [1] according to which information is essence of the Universe, and material objects are manifestation of the essence. The hypothesis is formulated as follows: (1) the Universe represents the cybernetic system; (2) the cybernetic system is a set of mutual connected elements which receive, memorize, process, and transmit information; (3) each material element (for example, atom, molecule, man, the Earth, the Sun) is a unity of opposites: the controlling aspect and the controllable aspect; (4) the Universe as a system is a unity of opposites: the controlling aspect and the controllable aspect. Consequently, the Universe is controlled by the certain object. Thus, the problem of definition of the controlling object arises. Correct solution of this problem is the key to exploration of the Universe. Ref.: [1] T.Z. Kalanov, ``On the hypothesis of Universe's ``system block'' ''. Bulletin of the APS, Vol. 51, No. 2 (2006), p. 61.

THE PERIOD RATIO FOR STANDING KINK AND SAUSAGE MODES IN SOLAR STRUCTURES WITH SIPHON FLOW. I. MAGNETIZED SLABS

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

Li Bo; Habbal, Shadia Rifai; Chen Yanjun, E-mail: bbl@sdu.edu.cn

2013-04-20

In the applications of solar magneto-seismology, the ratio of the period of the fundamental mode to twice the period of its first overtone, P{sub 1}/2P{sub 2}, plays an important role. We examine how field-aligned flows affect the dispersion properties, and hence the period ratios, of standing modes supported by magnetic slabs in the solar atmosphere. We numerically solve the dispersion relations and devise a graphic means to construct standing modes. For coronal slabs, we find that the flow effects are significant for the fast kink and sausage modes alike. For the kink ones, they may reduce P{sub 1}/2P{sub 2} bymore » up to 23% compared with the static case, and the minimum allowed P{sub 1}/2P{sub 2} can fall below the lower limit analytically derived for static slabs. For the sausage modes, while introducing the flow reduces P{sub 1}/2P{sub 2} by typically {approx}< 5% relative to the static case, it significantly increases the threshold aspect ratio only above which standing sausage modes can be supported, meaning that their detectability is restricted to even wider slabs. In the case of photospheric slabs, the flow effect is not as strong. However, standing modes are distinct from the coronal case in that standing kink modes show a P{sub 1}/2P{sub 2} that deviates from unity even for a zero-width slab, while standing sausage modes no longer suffer from a threshold aspect ratio. We conclude that transverse structuring in plasma density and flow speed should be considered in seismological applications of multiple periodicities to solar atmospheric structures.« less

A Multidimensional Approach to Training Mathematics Students at a University: Improving the Efficiency through the Unity of Social, Psychological and Pedagogical Aspects

ERIC Educational Resources Information Center

Kuznetsova, Elena; Matytcina, Marina

2018-01-01

The article deals with social, psychological and pedagogical aspects of teaching mathematics students at universities. The sociological portrait and the factors influencing a career choice of a mathematician have been investigated through the survey results of 198 first-year students of applied mathematics major at 27 state universities (Russia).…

Charging and shielding of a non-spherical dust grain in a plasma

NASA Astrophysics Data System (ADS)

Zhao, L.; Delzanno, G.

2013-12-01

The interaction of objects with a plasma is a classic problem of plasma physics. Originally, it was investigated in the framework of probe theory but more recently its interest has grown in connection with space and complex or dusty plasmas. It is customary to assume that the dust grains are spherical, and theories such as the Orbital Motion Limited (OML) theory are usually applied to calculate the dust charge. However, in nature dust grains have a variety of sizes and shapes. It is therefore natural to ask about the influence of the dust shape on the charging and shielding process. In order to answer this question, we study the charging and shielding of a non-spherical dust grain immersed in a Maxwellian plasma at rest. We consider prolate ellipsoids, varying parametrically the aspect ratio while keeping the surface area constant. The study is conducted with CPIC [1], a newly developed Particle-In-Cell code in curvilinear geometry that conforms to objects of arbitrary shape. For a plasma with temperature ratio equal to unity and for a dust grain with characteristic size of the order of the Debye length, it is shown that the floating potential has a very weak dependence on the geometry, while the charge on the grain increases by a factor of three when the aspect ratio changes from one (a sphere) to hundred (a needle-like ellipsoid). These results are consistent with the higher capacitance of ellipsoidal dust grains, but also indicate that the screening length depends on the geometry. Scaling studies of the dependence of the charging time and screening length on the aspect ratio and plasma conditions are presented, including theoretical considerations to support the numerical results. [1] G.L. Delzanno, et al, ';CPIC: a curvilinear Particle-In-Cell code for plasma-material interaction studies', under review.

Unification of force and substance.

PubMed

Wilczek, Frank

2016-08-28

Maxwell's mature presentation of his equations emphasized the unity of electromagnetism and mechanics, subsuming both as 'dynamical systems'. That intuition of unity has proved both fruitful, as a source of pregnant concepts, and broadly inspiring. A deep aspect of Maxwell's work is its use of redundant potentials, and the associated requirement of gauge symmetry. Those concepts have become central to our present understanding of fundamental physics, but they can appear to be rather formal and esoteric. Here I discuss two things: the physical significance of gauge invariance, in broad terms; and some tantalizing prospects for further unification, building on that concept, that are visible on the horizon today. If those prospects are realized, Maxwell's vision of the unity of field and substance will be brought to a new level.This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'. © 2016 The Author(s).

Practical implementation of the double linear damage rule and damage curve approach for treating cumulative fatigue damage

NASA Technical Reports Server (NTRS)

Manson, S. S.; Halford, G. R.

1980-01-01

Simple procedures are presented for treating cumulative fatigue damage under complex loading history using either the damage curve concept or the double linear damage rule. A single equation is provided for use with the damage curve approach; each loading event providing a fraction of damage until failure is presumed to occur when the damage sum becomes unity. For the double linear damage rule, analytical expressions are provided for determining the two phases of life. The procedure involves two steps, each similar to the conventional application of the commonly used linear damage rule. When the sum of cycle ratios based on phase 1 lives reaches unity, phase 1 is presumed complete, and further loadings are summed as cycle ratios on phase 2 lives. When the phase 2 sum reaches unity, failure is presumed to occur. No other physical properties or material constants than those normally used in a conventional linear damage rule analysis are required for application of either of the two cumulative damage methods described. Illustrations and comparisons of both methods are discussed.

Selection bias due to differential participation in a case-control study of mobile phone use and brain tumors.

PubMed

Lahkola, Anna; Salminen, Tiina; Auvinen, Anssi

2005-05-01

To evaluate the possible selection bias related to the differential participation of mobile phone users and non-users in a Finnish case-control study on mobile phone use and brain tumors. Mobile phone use was investigated among 777 controls and 726 cases participating in the full personal interview (full participants), and 321 controls and 103 cases giving only a brief phone interview (incomplete participants). To assess selection bias, the Mantel-Haenszel estimate of odds ratio was calculated for three different groups: full study participants, incomplete participants, and a combined group consisting of both full and incomplete participants. Among controls, 83% of the full participants and 73% of the incomplete participants had regularly used a mobile phone. Among cases, the figures were 76% and 64%, respectively. The odds ratio for brain tumor based on the combined group of full and incomplete participants was slightly closer to unity than that based only on the full participants. Selection bias tends to distort the effect estimates below unity, while analyses based on more comprehensive material gave results close to unity.

Practical implementation of the double linear damage rule and damage curve approach for treating cumulative fatigue damage

NASA Technical Reports Server (NTRS)

Manson, S. S.; Halford, G. R.

1981-01-01

Simple procedures are given for treating cumulative fatigue damage under complex loading history using either the damage curve concept or the double linear damage rule. A single equation is given for use with the damage curve approach; each loading event providing a fraction of damage until failure is presumed to occur when the damage sum becomes unity. For the double linear damage rule, analytical expressions are given for determining the two phases of life. The procedure comprises two steps, each similar to the conventional application of the commonly used linear damage rule. Once the sum of cycle ratios based on Phase I lives reaches unity, Phase I is presumed complete, and further loadings are summed as cycle ratios based on Phase II lives. When the Phase II sum attains unity, failure is presumed to occur. It is noted that no physical properties or material constants other than those normally used in a conventional linear damage rule analysis are required for application of either of the two cumulative damage methods described. Illustrations and comparisons are discussed for both methods.

Dissolution Kinetics of Spheroidal-Shaped Precipitates in Age-Hardenable Aluminum Alloys

NASA Astrophysics Data System (ADS)

Anjabin, Nozar; Salehi, Majid Seyed

2018-05-01

As a first attempt, a mathematical model is proposed to predict the dissolution kinetics of non-spherical secondary phase precipitates during solution heat treatment of age-hardenable aluminum alloys. The model uses general spheroidal geometry to describe the dissolution process of the alloys containing needle/disc-shaped particles with different size distributions in a finite matrix. It is found that as the aspect ratio deviates from unity, the dissolution rate is accelerated. Also, the dissolution rate of the particles in the alloy containing the particle size distribution is lower than that of mono-sized particles system. The modeling results for dissolution of θ' precipitates in an Al-Cu alloy are compared with experiments, and a good agreement was found between the modeling and the experimental results. The proposed model can be applied to different isothermal and non-isothermal annealing conditions.

Recurrent Education in Yugoslavia.

ERIC Educational Resources Information Center

Soljan, Niksa Nikola, Ed.

These seven papers offer an insight into the different aspects of recurrent education in Yugoslavia. "Recurrent Education and Educational Changes" considers these three processes: the "de-etatization," the democratization, and the de-schooling of education. "The Unity of Education and Work and Recurrent Education"…

The Persistence of the Self over Time in Mild Cognitive Impairment and Alzheimer's Disease

PubMed Central

Tippett, Lynette J.; Prebble, Sally C.; Addis, Donna Rose

2018-01-01

Diachronic unity is the belief that, despite changes, we are the same person across the lifespan. We propose that diachronic unity is supported by the experience of remembering the self over time during episodic recall (i.e., phenomenological continuity). However, we also predict that diachronic unity is also possible when episodic memory is impaired, as long as the ability to construct life narratives from semantic memory (i.e., semantic continuity) is intact. To examine this prediction, we investigated diachronic unity in Alzheimer's Disease (AD) and amnestic mild cognitive impairment (aMCI), two conditions characterised by disrupted phenomenological continuity. If semantic continuity is also altered in these conditions, there should be an associated deterioration in diachronic unity. Participants with AD, aMCI, and healthy controls (HC) completed a self-persistence interview measuring diachronic unity (beliefs about self-persistence, explanations for stability/change). Semantic continuity was assessed with a life-story interview measuring autobiographical reasoning (self-event connections), and coherence (temporal/thematic/causal) of narratives. Our results highlight a complex relationship between semantic continuity and diachronic unity and revealed a divergence between two aspects of diachronic unity: AD/aMCI groups did not differ from HC in continuity beliefs, but AD explanations for self-persistence were less sophisticated. Semantic continuity was most impaired in AD: their narratives had fewer self-event connections (vs. HCs) and lower temporal/thematic coherence (vs. HC/aMCI), while both AD/aMCI groups had lower causal coherence. Paradoxically AD participants who scored higher on measures of beliefs in the persistence of the core self, provided less sophisticated explanations for their self-persistence and were less able to explore persistence in their life narratives. These findings support the importance of semantic continuity to diachronic unity, but suggest a more nuanced and multifaceted relationship than originally proposed in our model. In AD, diminished life narratives that retain features of cultural life scripts are sufficient for strong subjective beliefs of self-persistence, but not for sophisticated explanations about persistence. Better semantic continuity, with the ability to weave high-quality life narratives, may scaffold the capacity to understand and explain one's diachronic unity, but this produces less surety about self-persistence. PMID:29515473

The Pegasus-Upgrade Experiment

NASA Astrophysics Data System (ADS)

Fonck, R. J.; Bongard, M. W.; Barr, J. L.; Frerichs, H. G.; Lewicki, B. T.; Reusch, J. A.; Schmitz, O.; Winz, G. R.

2015-11-01

Tokamak operation at near-unity aspect ratio provides access to advanced tokamak physics at modest parameters. High plasma current is accessible at very low toroidal field. This offers H-mode performance at Te levels that allow use of electrostatic and magnetic probe arrays through the edge pedestal region into the plasma core. An upgrade to the Pegasus ST is planned to exploit these features and pursue unique studies in three areas: local measurements of pedestal and ELM dynamics at Alfvenic timescales; direct measurement of the local plasma response to application of 3D magnetic perturbations with high spectral flexibility; and extension of Local Helicity Injection for nonsolenoidal startup to NSTX-U-relevant confinement and stability regimes. Significant but relatively low-cost upgrades to the facility are proposed: a new centerstack with larger solenoid and 2x the number of toroidal field conductors; a new TF power supply and conversion of the 200 MVA OH power supply to a cascaded multilevel inverter configuration; and installation of an extensive 3D-magnetic perturbation coil system for ELM mitigation and suppression studies. The upgraded facility will provide 0.3 MA plasmas with pulse lengths of 50-100 msec flattop, aspect ratio <1.25, and toroidal field up to 0.4 T. These research activities will be integrated into related efforts on DIII-D and NSTX-U. Work supported by US DOE grant DE-FG02-96ER54375.

Experimental investigation on thermo-magnetic convection inside cavities.

PubMed

Gontijo, R G; Cunha, F R

2012-12-01

This paper presents experimental results on thermo-magnetic convection inside cavities. We examine the flow induced by convective currents inside a cavity with aspect ratio near the unity and the heat transfer rates measurements inside a thin cavity with aspect ratio equal to twelve. The convective unstable currents are formed when a magnetic suspension is subjected to a temperature gradient combined with a gradient of an externally imposed magnetic field. Under these conditions, stratifications in the suspension density and susceptibility are both important effects to the convective motion. We show a comparison between flow patterns of magnetic and gravitational convections. The impact of the presence of a magnetic field on the amount of heat extracted from the system when magnetic and gravitational effects are combined inside the test cell is evaluated. The convection state is largely affected by new instability modes produced by stratification in susceptibility. The experiments reveal that magnetic field enhances the instability in the convective flow leading to a more effective mixing and consequently to a more statistically homogenous temperature distribution inside the test cell. The experimental results allow the validation of the scaling law proposed in a previous theoretical work that has predicted that the Nusselt number scales with the magnetic Rayleigh number to the power of 1/3, in the limit in which magnetic force balances viscous force in the convective flow.

Political Aspects of Communications and Information Resources in Canada.

ERIC Educational Resources Information Center

Ganley, Oswald H.

1981-01-01

Examines the effects of communications and information on Canadian unity, cultural identity, and economic viability. The discussion is illustrated with descriptions of Canadian computer communications; broadcasting, publishing, and film industries; telecommunications systems and satellites; and research and development trends. (Author/SW)

Precision limits of lock-in amplifiers below unity signal-to-noise ratios

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

Gillies, G.T.; Allison, S.W.

1986-02-01

An investigation of noise-related performance limits of commercial-grade lock-in amplifiers has been carried out. The dependence of the output measurement error on the input signal-to-noise ratio was established in each case and measurements of noise-related gain variations were made.

[Roles of additives and surface control in slurry atomization]. Quarterly report, March 1992

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

Not Available

1992-08-01

Our experimental results clearly demonstrate that the shape of particles with aspect ratio close to unity dictates the relative suspension viscosity. Suspensions of irregularly shaped particles have higher relative viscosities than suspensions of spherical particles at same volume fractions, in agreement with the reported results at high shear conditions. The relative viscosity of a Newtonian suspension is in excellent agreement with that predicted by the Krieger/Dougherty rigid sphere model using the maximum packing fraction determined from sedimentation as the sole parameter. The relative viscosity of a pseudoplastic suspension is independent of the particle density. It correlates well with the particlemore » Peclet number. The extent of particle diffusion at high shear rates decreases considerably as the particle size increases, and less energy is dissipated as a result. The interparticle electrostatic repulsion plays no significant role in the rheology of pseudoplastic nonaqueous and aqueous glycerol suspensions of noncolloidal particles.« less

(Roles of additives and surface control in slurry atomization)

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

Not Available

1992-01-01

Our experimental results clearly demonstrate that the shape of particles with aspect ratio close to unity dictates the relative suspension viscosity. Suspensions of irregularly shaped particles have higher relative viscosities than suspensions of spherical particles at same volume fractions, in agreement with the reported results at high shear conditions. The relative viscosity of a Newtonian suspension is in excellent agreement with that predicted by the Krieger/Dougherty rigid sphere model using the maximum packing fraction determined from sedimentation as the sole parameter. The relative viscosity of a pseudoplastic suspension is independent of the particle density. It correlates well with the particlemore » Peclet number. The extent of particle diffusion at high shear rates decreases considerably as the particle size increases, and less energy is dissipated as a result. The interparticle electrostatic repulsion plays no significant role in the rheology of pseudoplastic nonaqueous and aqueous glycerol suspensions of noncolloidal particles.« less

On the spatial evolution of long-wavelength Goertler vortices governed by a viscous-inviscid interaction

NASA Technical Reports Server (NTRS)

Choudhari, Meelan; Hall, Philip; Streett, Craig

1992-01-01

The generation of long-wavelength, viscous-inviscid interactive Goertler vortices is studied in the linear regime by numerically solving the time-dependent governing equations. It is found that time-dependent surface deformations, which assume a fixed nonzero shape at large times, generate steady Goertler vortices that amplify in the downstream direction. Thus, the Goertler instability in this regime is shown to be convective in nature, contrary to the earlier findings of Ruban and Savenkov. The disturbance pattern created by steady and streamwise-elongated surface obstacles on a concave surface is examined in detail, and also contrasted with the flow pattern due to roughness elements with aspect ratio of order unity on flat surfaces. Finally, the applicability of the Briggs-Bers criterion to unstable physical systems of this type is questioned by providing a counterexample in the form of the inviscid limit of interactive Goertler vortices.

Large-Eddy Simulation of Chemically Reactive Pollutant Transport from a Point Source in Urban Area

NASA Astrophysics Data System (ADS)

Du, Tangzheng; Liu, Chun-Ho

2013-04-01

Most air pollutants are chemically reactive so using inert scalar as the tracer in pollutant dispersion modelling would often overlook their impact on urban inhabitants. In this study, large-eddy simulation (LES) is used to examine the plume dispersion of chemically reactive pollutants in a hypothetical atmospheric boundary layer (ABL) in neutral stratification. The irreversible chemistry mechanism of ozone (O3) titration is integrated into the LES model. Nitric oxide (NO) is emitted from an elevated point source in a rectangular spatial domain doped with O3. The LES results are compared well with the wind tunnel results available in literature. Afterwards, the LES model is applied to idealized two-dimensional (2D) street canyons of unity aspect ratio to study the behaviours of chemically reactive plume over idealized urban roughness. The relation among various time scales of reaction/turbulence and dimensionless number are analysed.

Numerical design and optimization of hydraulic resistance and wall shear stress inside pressure-driven microfluidic networks.

PubMed

Damiri, Hazem Salim; Bardaweel, Hamzeh Khalid

2015-11-07

Microfluidic networks represent the milestone of microfluidic devices. Recent advancements in microfluidic technologies mandate complex designs where both hydraulic resistance and pressure drop across the microfluidic network are minimized, while wall shear stress is precisely mapped throughout the network. In this work, a combination of theoretical and modeling techniques is used to construct a microfluidic network that operates under minimum hydraulic resistance and minimum pressure drop while constraining wall shear stress throughout the network. The results show that in order to minimize the hydraulic resistance and pressure drop throughout the network while maintaining constant wall shear stress throughout the network, geometric and shape conditions related to the compactness and aspect ratio of the parent and daughter branches must be followed. Also, results suggest that while a "local" minimum hydraulic resistance can be achieved for a geometry with an arbitrary aspect ratio, a "global" minimum hydraulic resistance occurs only when the aspect ratio of that geometry is set to unity. Thus, it is concluded that square and equilateral triangular cross-sectional area microfluidic networks have the least resistance compared to all rectangular and isosceles triangular cross-sectional microfluidic networks, respectively. Precise control over wall shear stress through the bifurcations of the microfluidic network is demonstrated in this work. Three multi-generation microfluidic network designs are considered. In these three designs, wall shear stress in the microfluidic network is successfully kept constant, increased in the daughter-branch direction, or decreased in the daughter-branch direction, respectively. For the multi-generation microfluidic network with constant wall shear stress, the design guidelines presented in this work result in identical profiles of wall shear stresses not only within a single generation but also through all the generations of the microfluidic network under investigation. The results obtained in this work are consistent with previously reported data and suitable for a wide range of lab-on-chip applications.

Numerical and analytical modelling of the MHD buoyancy-driven flow in a Bridgman crystal growth configuration

NASA Astrophysics Data System (ADS)

Davoust, L.; Moreau, R.; Cowley, M. D.; Tanguy, P. A.; Bertrand, F.

1997-10-01

We present analytical and numerical models of magnetohydrodynamic(MHD) buoyancy-driven flow within the liquid pool of a horizontal Bridgman crystal growth furnace, under the influence of a uniform vertical magnetic field B0. A horizontal differentially heated cylinder, whose aspect ratio (radius to length) is small enough for a fully developed regime to be established in the central core, is considered. With Hartmann layers remaining electrically inactive, a modified Rayleigh number RaG, which is the ration of the ordinary Rayleigh number to the square of the Hartmann number, is found to control the MHD reorganisation of the flow. This modified Rayleigh number is a measure of the importance of thermal convection relative to diffusion if velocity is estimated from the balance between the torques of buoyancy and the Laplace force. When RaG is much smaller than unity (quasi-diffusive regime), an analytical modelling of the flow, based on a power series of RaG, demonstrates that this balance requires secondary vortices within vertical mid-planes of the cylinder, both within the core flow and near the end walls. A 3-D numerical calculation of the flow provides evidence of the transition from a convective MHD flow (when RaG is still of the order of unity) to the quasi-diffusive flow, analytically studied. Indeed, this transition takes the form of a rather complex 3-D MHD organisation of the flow which is due to the nonuniformity of the axial temperature gradient along the cylinder.

NATO Standardization and Licensing Policy-Exploratory Phase. Volume 3. Supplement

DTIC Science & Technology

1976-11-30

Aerospatiale will perform at least half the production of this aircraft.* The concept involves a relatively light- weight advanced interceptor with...a ratio of total thrust to takeoff gross weight of about unity. The technology of the aircraft calls for the use of carbon fiber in selected...presenting a system with operating temperatures, pressure ratios, and thrust-to- weight ratios roughly comparable to U.S. technology. The

Characterization of peeling modes in a low aspect ratio tokamak

NASA Astrophysics Data System (ADS)

Bongard, M. W.; Thome, K. E.; Barr, J. L.; Burke, M. G.; Fonck, R. J.; Hinson, E. T.; Redd, A. J.; Schlossberg, D. J.

2014-11-01

Peeling modes are observed at the plasma edge in the Pegasus Toroidal Experiment under conditions of high edge current density (Jedge ˜ 0.1 MA m-2) and low magnetic field (B ˜ 0.1 T) present at near-unity aspect ratio. Their macroscopic properties are measured using external Mirnov coil arrays, Langmuir probes and high-speed visible imaging. The modest edge parameters and short pulse lengths of Pegasus discharges permit direct measurement of the internal magnetic field structure with an insertable array of Hall-effect sensors, providing the current profile and its temporal evolution. Peeling modes generate coherent, edge-localized electromagnetic activity with low toroidal mode numbers n ⩽ 3 and high poloidal mode numbers, in agreement with theoretical expectations of a low-n external kink structure. Coherent MHD fluctuation amplitudes are found to be strongly dependent on the experimentally measured Jedge/B peeling instability drive, consistent with theory. Peeling modes nonlinearly generate ELM-like, field-aligned filamentary structures that detach from the edge and propagate radially outward. The KFIT equilibrium code is extended with an Akima spline profile parameterization and an improved model for induced toroidal wall current estimation to obtain a reconstruction during peeling activity with its current profile constrained by internal Hall measurements. It is used to test the analytic peeling stability criterion and numerically evaluate ideal MHD stability. Both approaches predict instability, in agreement with experiment, with the latter identifying an unstable external kink.

Magnetics and Power System Upgrades for the Pegasus-U Experiment

NASA Astrophysics Data System (ADS)

Preston, R. C.; Bongard, M. W.; Fonck, R. J.; Lewicki, B. T.

2014-10-01

To support the missions of developing local helicity injection startup and exploiting advanced tokamak physics studies at near unity aspect ratio, the proposed Pegasus-U will include expanded magnetic systems and associated power supplies. A new centerstack increases the toroidal field seven times to 1 T and the volt-seconds by a factor of six while maintaining operation at an aspect ratio of 1.2. The poloidal field magnet system is expanded to support improved shape control and robust double or single null divertor operation at the full plasma current of 0.3 MA. An integrated digital control system based on Field Programmable Gate Arrays (FPGAs) provides active feedback control of all magnet currents. Implementation of the FPGAs is achieved with modular noise reducing electronics. The digital feedback controllers replace the existing analog systems and switch multiplexing technology. This will reduce noise sensitivity and allow the operational Ohmic power supply voltage to increase from 2100 V to its maximum capacity of 2400 V. The feedback controller replacement also allows frequency control for ``freewheeling''--stopping the switching for a short interval and allowing the current to coast. The FPGAs assist in optimizing pulse length by having programmable switching events to minimize energy losses. They also allow for more efficient switching topologies that provide improved stored energy utilization, and support increasing the pulse length from 25 ms to 50-100 ms. Work supported by US DOE Grant DE-FG02-96ER54375.

Humanities and Science: A Necessary Unity for the Counseling Profession

ERIC Educational Resources Information Center

Guterman, Jeffrey T.; Martin, Clayton V.; Kopp, David M.

2012-01-01

This article is a reply to Hansen's (2012) call for the counseling profession to embrace a purely humanistic ideology for counseling. The authors suggest the relationship between humanities and science set forth by Hansen does not emphasize the both-and aspects of these ideologies. An integrative framework is considered for counseling.

Heterogeneous reactions in aircraft gas turbine engines

NASA Astrophysics Data System (ADS)

Brown, R. C.; Miake-Lye, R. C.; Lukachko, S. P.; Waitz, I. A.

2002-05-01

One-dimensional flow models and unity probability heterogeneous rate parameters are used to estimate the maximum effect of heterogeneous reactions on trace species evolution in aircraft gas turbines. The analysis includes reactions on soot particulates and turbine/nozzle material surfaces. Results for a representative advanced subsonic engine indicate the net change in reactant mixing ratios due to heterogeneous reactions is <10-6 for O2, CO2, and H2O, and <10-10 for minor combustion products such as SO2 and NO2. The change in the mixing ratios relative to the initial values is <0.01%. Since these estimates are based on heterogeneous reaction probabilities of unity, the actual changes will be even lower. Thus, heterogeneous chemistry within the engine cannot explain the high conversion of SO2 to SO3 which some wake models require to explain the observed levels of volatile aerosols. Furthermore, turbine heterogeneous processes will not effect exhaust NOx or NOy levels.

Direct numerical simulation of incompressible acceleration-driven variable-density turbulence

NASA Astrophysics Data System (ADS)

Gat, Ilana; Matheou, Georgios; Chung, Daniel; Dimotakis, Paul

2015-11-01

Fully developed turbulence in variable-density flow driven by an externally imposed acceleration field, e.g., gravity, is fundamental in many applications, such as inertial confinement fusion, geophysics, and astrophysics. Aspects of this turbulence regime are poorly understood and are of interest to fluid modeling. We investigate incompressible acceleration-driven variable-density turbulence by a series of direct numerical simulations of high-density fluid in-between slabs of low-density fluid, in a triply-periodic domain. A pseudo-spectral numerical method with a Helmholtz-Hodge decomposition of the pressure field, which ensures mass conservation, is employed, as documented in Chung & Pullin (2010). A uniform dynamic viscosity and local Schmidt number of unity are assumed. This configuration encapsulates a combination of flow phenomena in a temporally evolving variable-density shear flow. Density ratios up to 10 and Reynolds numbers in the fully developed turbulent regime are investigated. The temporal evolution of the vertical velocity difference across the shear layer, shear-layer growth, mean density, and Reynolds number are discussed. Statistics of Lagrangian accelerations of fluid elements and of vorticity as a function of the density ratio are also presented. This material is based upon work supported by the AFOSR, the DOE, the NSF GRFP, and Caltech.

Beauty vector meson decay constants from QCD sum rules

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

Lucha, Wolfgang; Melikhov, Dmitri; D. V. Skobeltsyn Institute of Nuclear Physics, M. V. Lomonosov Moscow State University, 119991, Moscow

We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.

Utilising E-on Vue and Unity 3D scenes to generate synthetic images and videos for visible signature analysis

NASA Astrophysics Data System (ADS)

Madden, Christopher S.; Richards, Noel J.; Culpepper, Joanne B.

2016-10-01

This paper investigates the ability to develop synthetic scenes in an image generation tool, E-on Vue, and a gaming engine, Unity 3D, which can be used to generate synthetic imagery of target objects across a variety of conditions in land environments. Developments within these tools and gaming engines have allowed the computer gaming industry to dramatically enhance the realism of the games they develop; however they utilise short cuts to ensure that the games run smoothly in real-time to create an immersive effect. Whilst these short cuts may have an impact upon the realism of the synthetic imagery, they do promise a much more time efficient method of developing imagery of different environmental conditions and to investigate the dynamic aspect of military operations that is currently not evaluated in signature analysis. The results presented investigate how some of the common image metrics used in target acquisition modelling, namely the Δμ1, Δμ2, Δμ3, RSS, and Doyle metrics, perform on the synthetic scenes generated by E-on Vue and Unity 3D compared to real imagery of similar scenes. An exploration of the time required to develop the various aspects of the scene to enhance its realism are included, along with an overview of the difficulties associated with trying to recreate specific locations as a virtual scene. This work is an important start towards utilising virtual worlds for visible signature evaluation, and evaluating how equivalent synthetic imagery is to real photographs.

Tensor non-Gaussianity from axion-gauge-fields dynamics: parameter search

NASA Astrophysics Data System (ADS)

Agrawal, Aniket; Fujita, Tomohiro; Komatsu, Eiichiro

2018-06-01

We calculate the bispectrum of scale-invariant tensor modes sourced by spectator SU(2) gauge fields during inflation in a model containing a scalar inflaton, a pseudoscalar axion and SU(2) gauge fields. A large bispectrum is generated in this model at tree-level as the gauge fields contain a tensor degree of freedom, and its production is dominated by self-coupling of the gauge fields. This is a unique feature of non-Abelian gauge theory. The shape of the tensor bispectrum is approximately an equilateral shape for 3lesssim mQlesssim 4, where mQ is an effective dimensionless mass of the SU(2) field normalised by the Hubble expansion rate during inflation. The amplitude of non-Gaussianity of the tensor modes, characterised by the ratio Bh/P2h, is inversely proportional to the energy density fraction of the gauge field. This ratio can be much greater than unity, whereas the ratio from the vacuum fluctuation of the metric is of order unity. The bispectrum is effective at constraining large mQ regions of the parameter space, whereas the power spectrum constrains small mQ regions.

Is the Prince Listening? Politics of Education and the Policymaker.

ERIC Educational Resources Information Center

Wirt, Frederick M.

This paper explores the politics of education with emphasis on the uses and influences of educational research in educational policy formation. Objectives are to identify information needs of policy makers and to shed light on the educational policy process. The hypothesis is that there is a lack of unity in studies of the political aspects of…

The Cultural-Historical Basis of the "Golden Key" Program

ERIC Educational Resources Information Center

Kravtsov, Genady G.; Kravtsova, Elena E.

2011-01-01

The "Golden Key" programme is a preschool education programme that is constructed on the basis of Vygotskij's cultural-historical theory. One of the most important aspects of this theory is not just the unity of intellect and affect, but the fact that the relationship between these two changes during the course of development. In infants, affect…

Analyse conversationnelle et representations sociales: Unite et diversite de L'image du bilinguisme (Conversational Analysis and Social Representations: Unity and Diversity in the Image of Bilingualism).

ERIC Educational Resources Information Center

Py, Bernard, Ed.

2000-01-01

Articles in this issue include the following: "Representations sociales et discours. Questions epistemologiques et methodologiques" (Social Representations and Discourse. Questions of Epistemology and Methodology); "Aspects theoretiques et methodologiques de la recherche sur le traitement discursif des representations sociales"…

Reconnection in Compressible Plasmas: Extended Conversion Region

NASA Technical Reports Server (NTRS)

Birn, J.; Hesse, M.; Zenitani, S.

2011-01-01

The classical Sweet-Parker approach to steady-state magnetic reconnection is extended into the regime of large resistivity (small magnetic Reynolds or Lundquist number) when the aspect ratio between the outflow and inflow scale, delta = d/L, approaches unity. In a previous paper the vicinity of the dissipation site ("diffusion region") was investigated. In this paper, the approach is extended to cover larger sites, in which the energy transfer and conversion is not confined to the diffusion region. Consistent with the results of Paper I, we find that increasing aspect ratio delta is associated with increasing compression, increasing reconnect ion rate for low Beta, but slightly decreasing rate for higher Beta, decreasing outflow speed, and increasing outflow magnetic field. These trends are stronger for lower Beta. Deviations from the traditional Sweet-Parker limit delta approaches 0 become significant for R(sub m) approx < 10, where R(sub m) is the magnetic Reynolds number (Lundquist number) based on the half-thickness of the current layer responsible for the Ohmic dissipation. They are also more significant for small gamma, that is, for increasing compressibility. In contrast to the results of Paper I, but consistent with earlier results for delta much < 1,nu(sub A) we find that in this limit the outflow speed is given by the Alfven speed nu(sub A) in the inflow region and the energy conversion is given by an even split of Poynting flux into enthalpy flux and bulk kinetic energy flux. However, with increasing delta the conversion to enthalpy flux becomes more and more dominant.

The importance of utility systems in today's biorefineries and a vision for tomorrow.

PubMed

Eggeman, Tim; Verser, Dan

2006-01-01

Heat and power systems commonly found in today's corn processing facilities, sugar mills, and pulp and paper mills will be reviewed. We will also examine concepts for biorefineries of the future. We will show that energy ratio, defined as the ratio of renewable energy produced divided by the fossil energy input, can vary widely from near unity to values greater than 12. Renewable-based utility systems combined with low-fossil input agricultural systems lead to high-energy ratios.

Optimized merging of search coil and fluxgate data for MMS

NASA Astrophysics Data System (ADS)

Fischer, David; Magnes, Werner; Hagen, Christian; Dors, Ivan; Chutter, Mark W.; Needell, Jerry; Torbert, Roy B.; Le Contel, Olivier; Strangeway, Robert J.; Kubin, Gernot; Valavanoglou, Aris; Plaschke, Ferdinand; Nakamura, Rumi; Mirioni, Laurent; Russell, Christopher T.; Leinweber, Hannes K.; Bromund, Kenneth R.; Le, Guan; Kepko, Lawrence; Anderson, Brian J.; Slavin, James A.; Baumjohann, Wolfgang

2016-11-01

The Magnetospheric Multiscale mission (MMS) targets the characterization of fine-scale current structures in the Earth's tail and magnetopause. The high speed of these structures, when traversing one of the MMS spacecraft, creates magnetic field signatures that cross the sensitive frequency bands of both search coil and fluxgate magnetometers. Higher data quality for analysis of these events can be achieved by combining data from both instrument types and using the frequency bands with best sensitivity and signal-to-noise ratio from both sensors. This can be achieved by a model-based frequency compensation approach which requires the precise knowledge of instrument gain and phase properties. We discuss relevant aspects of the instrument design and the ground calibration activities, describe the model development and explain the application on in-flight data. Finally, we show the precision of this method by comparison of in-flight data. It confirms unity gain and a time difference of less than 100 µs between the different magnetometer instruments.

Non-inductively driven tokamak plasmas at near-unity βt in the Pegasus toroidal experiment

NASA Astrophysics Data System (ADS)

Reusch, J. A.; Bodner, G. M.; Bongard, M. W.; Burke, M. G.; Fonck, R. J.; Pachicano, J. L.; Perry, J. M.; Pierren, C.; Rhodes, A. T.; Richner, N. J.; Rodriguez Sanchez, C.; Schlossberg, D. J.; Weberski, J. D.

2018-05-01

A major goal of the spherical tokamak (ST) research program is accessing a state of low internal inductance ℓi, high elongation κ, and high toroidal and normalized beta ( βt and βN) without solenoidal current drive. Local helicity injection (LHI) in the Pegasus ST [Garstka et al., Nucl. Fusion 46, S603 (2006)] provides non-solenoidally driven plasmas that exhibit these characteristics. LHI utilizes compact, edge-localized current sources for plasma startup and sustainment. It results in hollow current density profiles with low ℓi. The low aspect ratio ( R0/a ˜1.2 ) of Pegasus allows access to high κ and high normalized plasma currents ( IN=Ip/a BT>14 ). Magnetic reconnection during LHI provides auxiliary ion heating. Together, these features provide access to very high βt plasmas. Equilibrium analyses indicate that βt up to ˜100% is achieved. These high βt discharges disrupt at the ideal no-wall β limit at βN˜7.

Coupling of Peridynamics and Finite Element Formulation for Multiscale Simulations

DTIC Science & Technology

2012-10-16

unidirectional fiber - reinforced composites, Computer Methods in Applied Mechanics and Engineering 217 (2012) 247-261. [44] S. A. Silling, M. Epton...numerical testing for different grid widths to horizon ratios , (4) development of an approach to add another material variable in the given approach...partition of unity principle, (3) numerical testing for different grid widths to horizon ratios , (4) development of an approach to add another

[Methodological aspect, application and evaluation of the delegation of tasks of the recalage of images].

PubMed

Ponsard, N

2016-10-01

Application and evaluation of the delegation of tasks of the recalage of images, the example of the authorization of the manipulators of the unity (unit) of radiotherapy of the Hospital center of Quimper. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Computer analysis of environmental temperature, light and noise in intensive care: chaos or chronome nurseries?

PubMed

Ardura, J; Andrés, J; Aldana, J; Revilla, M A; Cornélissen, G; Halberg, F

1997-09-01

Lighting, noise and temperature were monitored in two perinatal nurseries. Rhythms of several frequencies were found, including prominent 24-hour rhythms with acrophases around 13:00 (light intensity) and 16:00 (noise). For light and noise, the ratio formed by dividing the amplitude of a 1-week (circaseptan) or half-week (circasemiseptan) fitted cosine curve by the amplitude of a 24-hour fitted cosine curve is smaller than unity, since 24-hour rhythms are prominent for these variables. The amplitude ratios are larger than unity for temperature in the newborns' unit but not in the infants' unit. Earlier, the origin of the about-7-day rhythms of neonatal physiologic variables was demonstrated to have, in addition to a major endogenous, also a minor exogenous component. Hence, the possibility of optimizing maturation by manipulating environmental changes can be considered, using, as gauges of development, previously mapped chronomes (time structures of biologic multifrequency rhythms, trends and noise).

Hans Loewald and the transformation of passion.

PubMed

Lang, Frances

2009-01-01

Loewald's writing is notable for its musicality as well as for its content. In this article, possible early determinants of this salient aspect of his work are discussed. The intensity of Loewald's regard for Freud and, in particular, his attentiveness to Freud's language are explored. Loewald's views on the legitimacy of transference as an ongoing aspect of human motivation is discussed, along with the possible emergence in Loewald's own writing of transferences toward Freud--both oedipal level conflicts regarding parricide and preoedipal concerns regarding unity and separation. Sublimation, a process Loewald viewed as an extension of internalization, is seen as foundational to his achievement.

Mind over matter? I: philosophical aspects of the mind-brain problem.

PubMed

Schimmel, P

2001-08-01

To conceptualize the essence of the mind-body or mind-brain problem as one of metaphysics rather than science, and to propose a formulation of the problem in the context of current scientific knowledge and its limitations. The background and conceptual parameters of the mind-body problem are delineated, and the limitations of brain research in formulating a solution identified. The problem is reformulated and stated in terms of two propositions. These constitute a 'double aspect theory'. The problem appears to arise as a consequence of the conceptual limitations of the human mind, and hence remains essentially a metaphysical one. A 'double aspect theory' recognizes the essential unity of mind and brain, while remaining consistent with the dualism inherent in human experience.

Method for computing a roughness factor for veneer surfaces

Treesearch

Chung-Yun Hse

1972-01-01

Equations for determining the roughness factor (ratio of true surface to apparent area) of rotary-cut veneer were derived from an assumed tracheid model. With data measured on southern pine veneers, the equations indicated that the roughness factor of latewood was near unity, whereas that of earlywood was about 2.

Infrared spectra in monitoring biochemical parameters of human blood

NASA Astrophysics Data System (ADS)

Prabhakar, S.; Jain, N.; Singh, R. A.

2012-05-01

Infrared spectroscopy is gaining recognition as a promising method. The infrared spectra of selected regions (2000-400cm-1) of blood tissue samples are reported. Present study related to the role of spectral peak fitting in the study of human blood and quantitative interpretations of infrared spectra based on chemometrics. The spectral variations are interpreted in terms of the biochemical and pathological processes involved. The mean RNA/DNA ratio of fitted intensities and analytical area as calculated from the transmittance peaks at 1121cm-1/1020cm-1 is found to be 0.911A.U and 2.00A.U. respectively. The ratio of 1659cm-1/1544cm-1 (amide-I/amide-II) bands is found to shed light on the change in the DNA content. The ratio of amide-I/amide-II is almost unity (≈1.054) for blood spectra. The deviation from unity is an indication of DNA absorption from the RBC cells. The total phosphate content has found to be 25.09A.U. The level for glycogen/phosphate ratio (areas under peaks 1030cm-1/1082cm-1) is found to be 0.286A.U. The ratio of unsaturated and saturated carbonyl compounds (C=O) in blood samples is in form of esters and the analytical areas under the spectral peaks at 1740cm-1 and 1731cm-1 for unsaturated esters and saturated esters respectively found to be 0.618A.U.

Tracing the atomic nitrogen abundance in star-forming regions with ammonia deuteration

NASA Astrophysics Data System (ADS)

Furuya, Kenji; Persson, Magnus V.

2018-06-01

Partitioning of elemental nitrogen in star-forming regions is not well constrained. Most nitrogen is expected to be partitioned among atomic nitrogen (N I), molecular nitrogen (N_2), and icy N-bearing molecules, such as NH_3 and N_2. N I is not directly observable in the cold gas. In this paper, we propose an indirect way to constrain the amount of N I in the cold gas of star-forming clouds, via deuteration in ammonia ice, the [ND2H/NH2D]/[NH2D/NH3] ratio. Using gas-ice astrochemical simulations, we show that if atomic nitrogen remains as the primary reservoir of nitrogen during cold ice formation stages, the [ND2H/NH2D]/[NH2D/NH3] ratio is close to the statistical value of 1/3 and lower than unity, whereas if atomic nitrogen is largely converted into N-bearing molecules, the ratio should be larger than unity. Observability of ammonia isotopologues in the inner hot regions around low-mass protostars, where ammonia ice has sublimated, is also discussed. We conclude that the [ND2H/NH2D]/[NH2D/NH3] ratio can be quantified using a combination of Very Large Array and Atacama Large Millimeter/submillimeter Array observations with reasonable integration times, at least towards IRAS 16293-2422, where high molecular column densities are expected.

Corrosion resistance, mechanical properties, corrosion fatigue strength and cytocompatibility of new Ti alloys without Al and V.

PubMed

Okazaki, Y; Rao, S; Ito, Y; Tateishi, T

1998-07-01

The effects of various metallic ions using various metallic powders on the relative growth ratio of fibroblasts L929 and osteoblasts MC3T3-E1 cells were carried out. Ti, Zr, Sn, Nb and Ta had evidently no effect on the relative growth ratios of cells. Otherwise, Al and V ions exhibit cytotoxicity from a concentration of > or = 0.2 ppm. This Al effect on cells tend to be stronger in medium containing small quantity of V ions (< or = 0.03 ppm). The new Ti-15%Zr-4%Nb-4%Ta-0.2%Pd alloy exhibited a higher corrosion resistance in physiological saline solution. The addition of 0.02%O and 0.05%N to Ti-Zr alloy improved the mechanical properties at room temperature and corrosion fatigue strength. The relative growth ratios for the new Ti alloy plate and the alloy block extraction were unity. Further, the relative growth ratios were almost unity for the new Ti alloy against apatite ceramic pins up to 10(5) wear cycles in Eagle's MEM solution. However, there was a sharp decrease for Ti-6%Al-4%V ELI alloy from 3 x 10(4) wear cycles as V ion was released during wear into the wear test solution since the pH of the Eagle's MEM increases with increasing wear cycles.

The H-alpha/H-beta ratio in solar flares

NASA Technical Reports Server (NTRS)

Zirin, H.; Liggett, M.; Patterson, A.

1982-01-01

The present investigation involves the study of an extensive body of data accumulated of simultaneous H-alpha and H-beta cinematography of flares. The data were obtained with two telescopes simultaneously photographing flares in H-alpha and H-beta. The results of measurements in a number of flares are presented in a table. The flares were selected purely by optical quality of the data. That the measured ratios are not too different from those in stellar flares is suggested by the last two columns of the table. These columns show that a variety of possible line width ratios could give an integrated intensity ratio of less than unity.

Shock-tube measurements of carbon to oxygen atom ratios for incipient soot formation with C2H2, C2H4 and C2H6 fuels

NASA Technical Reports Server (NTRS)

Radcliffe, S. W.; Appleton, J. P.

1971-01-01

The critical atomic carbon to oxygen ratios, Phi sub C, for incipient soot formation in shock heated acetylene, ethylene, ethane/oxygen/ argon mixtures was measured over the temperature range 2000 K to 2500 K for reactant partial pressures between 0.1 and 0.4 atoms. Absorption of light from a He-Ne laser at 6328A was was used to detect soot. It was observed that the values of Phi sub C for all three fuels increased uniformly with temperature such that at the highest temperatures Phi sub C was considerably greater than unity, i.e. greater than the value of about unity at which solid carbon should have been precipitated on a thermochemical equilibrium basis. Observations were made over periods extending up to about one millisecond, which was well in excess of the time required for the major heat release of the combustion reactions. The relevance of these experimental findings to the problem of soot formation in gas turbine combustion chambers is discussed.

Feedback attribution of the land-sea warming contrast in a global warming simulation of the NCAR CCSM4

DOE PAGES

Sejas, Sergio A.; Albert, Oriene S.; Cai, Ming; ...

2014-12-02

One of the salient features in both observations and climate simulations is a stronger land warming than sea. This paper provides a quantitative understanding of the main processes that contribute to the land-sea warming asymmetry in a global warming simulation of the NCAR CCSM4. The CO 2 forcing alone warms the surface nearly the same for both land and sea, suggesting that feedbacks are responsible for the warming contrast. Our analysis on one hand confirms that the principal contributor to the above-unity land-to-sea warming ratio is the evaporation feedback; on the other hand the results indicate that the sensible heatmore » flux feedback has the largest land-sea warming difference that favors a greater ocean than land warming. Furthermore, the results uniquely highlight the importance of other feedbacks in establishing the above-unity land-to-sea warming ratio. Particularly, the SW cloud feedback and the ocean heat storage in the transient response are key contributors to the greater warming over land than sea.« less

Feedback attribution of the land-sea warming contrast in a global warming simulation of the NCAR CCSM4

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

Sejas, Sergio A.; Albert, Oriene S.; Cai, Ming

One of the salient features in both observations and climate simulations is a stronger land warming than sea. This paper provides a quantitative understanding of the main processes that contribute to the land-sea warming asymmetry in a global warming simulation of the NCAR CCSM4. The CO 2 forcing alone warms the surface nearly the same for both land and sea, suggesting that feedbacks are responsible for the warming contrast. Our analysis on one hand confirms that the principal contributor to the above-unity land-to-sea warming ratio is the evaporation feedback; on the other hand the results indicate that the sensible heatmore » flux feedback has the largest land-sea warming difference that favors a greater ocean than land warming. Furthermore, the results uniquely highlight the importance of other feedbacks in establishing the above-unity land-to-sea warming ratio. Particularly, the SW cloud feedback and the ocean heat storage in the transient response are key contributors to the greater warming over land than sea.« less

Non-inductively driven tokamak plasmas at near-unity β t in the Pegasus toroidal experiment

DOE PAGES

Reusch, Joshua A.; Bodner, Grant M.; Bongard, Michael W.; ...

2018-03-14

Amore » major goal of the spherical tokamak (ST) research program is accessing a state of low internal inductance ℓ i , high elongation κ , and high toroidal and normalized beta ( β t and β N ) without solenoidal current drive. Local helicity injection (LHI) in the Pegasus ST [Garstka et al., Nucl. Fusion 46, S603 (2006)] provides non-solenoidally driven plasmas that exhibit these characteristics. LHI utilizes compact, edge-localized current sources for plasma startup and sustainment. It results in hollow current density profiles with low ℓ i . The low aspect ratio ( R 0 / a ~ 1.2 ) of Pegasus allows access to high κ and high normalized plasma currents I N = I p / a B T > 14 ). Magnetic reconnection during LHI provides auxiliary ion heating. Together, these features provide access to very high β t plasmas. Equilibrium analyses indicate that β t up to ~100% is achieved. Finally, these high β t discharges disrupt at the ideal no-wall β limit at β N ~ 7. « less

A new scaling law for temperature variance profile in the mixing zone of turbulent Rayleigh-Bénard convection

NASA Astrophysics Data System (ADS)

Wang, Yin; Xu, Wei; He, Xiao-Zhou; Yik, Hiu-Fai; Wang, Xiao-Ping; Schumacher, Jorg; Tong, Penger

2017-11-01

We report a combined experimental and numerical study of the scaling properties of the temperature variance profile η(z) along the central z axis of turbulent Rayleigh-Bénard convection in a thin disk cell and an upright cylinder of aspect ratio unity. In the mixing zone outside the thermal boundary layer region, the measured η(z) is found to scale with the cell height H in both cells and obey a power law, η(z) (z/H)ɛ, with the obtained values of ɛ being very close to -1. Based on the experimental and numerical findings, we derive a new equation for η(z) in the mixing zone, which has a power-law solution in good agreement with the experimental and numerical results. Our work thus provides a common framework for understanding the effect of boundary layer fluctuations on the scaling properties of the temperature variance profile in turbulent Rayleigh-Bénard convection. This work was supported in part by Hong Kong Research Grants Council.

Hyperbolic umbilic caustics from oblate water drops with tilted illumination: Observations

NASA Astrophysics Data System (ADS)

Jobe, Oli; Thiessen, David B.; Marston, Philip L.

2017-11-01

Various groups have reported observations of hyperbolic umbilic diffraction catastrophe patterns in the far-field scattering by oblate acoustically levitated drops with symmetric illumination. In observations of that type the drop's symmetry axis is vertical and the illuminating light beam (typically an expanded laser beam) travels horizontally. In the research summarized here, scattering patterns in the primary rainbow region and drop measurements were recorded with vertically tilted laser beam illumination having a grazing angle as large as 4 degrees. The findings from these observations may be summarized as follows: (a) It remains possible to adjust the drop aspect ratio (diameter/height) = D/H so as to produce a V-shaped hyperbolic umbilic focal section (HUFS) in the far-field scattering. (b) The shift in the required D/H was typically an increase of less than 1% and was quadratic in the tilt. (c) The apex of the V-shaped HUFS was shifted vertically by an amount proportional to the tilt with a coefficient close to unity. The levitated drops had negligible up-down asymmetry. Our method of investigation should be useful for other generalized rainbows with tilted illumination.

Non-inductively driven tokamak plasmas at near-unity β t in the Pegasus toroidal experiment

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

Reusch, Joshua A.; Bodner, Grant M.; Bongard, Michael W.

Amore » major goal of the spherical tokamak (ST) research program is accessing a state of low internal inductance ℓ i , high elongation κ , and high toroidal and normalized beta ( β t and β N ) without solenoidal current drive. Local helicity injection (LHI) in the Pegasus ST [Garstka et al., Nucl. Fusion 46, S603 (2006)] provides non-solenoidally driven plasmas that exhibit these characteristics. LHI utilizes compact, edge-localized current sources for plasma startup and sustainment. It results in hollow current density profiles with low ℓ i . The low aspect ratio ( R 0 / a ~ 1.2 ) of Pegasus allows access to high κ and high normalized plasma currents I N = I p / a B T > 14 ). Magnetic reconnection during LHI provides auxiliary ion heating. Together, these features provide access to very high β t plasmas. Equilibrium analyses indicate that β t up to ~100% is achieved. Finally, these high β t discharges disrupt at the ideal no-wall β limit at β N ~ 7. « less

Emittance of a finite scattering medium with refractive index greater than unity

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

Crosbie, A.L.

1980-01-01

Refractive index and scattering can significantly influence the transfer of radiation in a semitransparent medium such as water, glass, plastics, or ceramics. In a recent article (1979), the author presented exact numerical results for the emittance of a semiinfinite scattering medium with a refractive index greater than unity. The present investigation extends the analysis to a finite medium. The physical situation consists of a finite planar layer. The isothermal layer emits, absorbs, and isotropically scatters thermal radiation. It is characterized by single scattering albedo, optical thickness, refractive index, and temperature. A formula for the directional emittance is derived, the directionalmore » emittance being the emittance of the medium multiplied by the interface transmittance. The ratio of hemispherical to normal emittance is tabulated and discussed.« less

Fabrication of CdS nanowires with increasing anionic precursor by SILAR method

NASA Astrophysics Data System (ADS)

Dariani, R. S.; Salehi, F.

2016-05-01

CdS nanowires were fabricated on glass substrate at room temperature by SILAR method with cadmium nitrate cationic and sodium sulfide anionic precursors. The deposition were done at different S:Cd concentration ratios of 1:1, 3:1, 5:1, and 7:1. Nanowires growth procedure was studied in the mentioned concentrations. The number of immersion cycles was kept constant at 15 cycles. EDX analysis showed that in all stoichiometric ratios, S/Cd composition ratio remains at about unity. Our results indicated that S:Cd concentration ratio of 7:1 had the longest nanowires with hexagonal structure. The main objective of this paper was to produce CdS nanowires with increasing concentration of sulfur.

Production of muons from heavy-flavour hadron decays in p-Pb collisions at √{sNN} = 5.02 TeV

NASA Astrophysics Data System (ADS)

Acharya, S.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, N.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altsybeev, I.; Alves Garcia Prado, C.; An, M.; Andrei, C.; Andrews, H. A.; Andronic, A.; Anguelov, V.; Anson, C.; Antičić, T.; Antinori, F.; Antonioli, P.; Anwar, R.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Ball, M.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barioglio, L.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Beltran, L. G. E.; Belyaev, V.; Bencedi, G.; Beole, S.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Blair, J. T.; Blau, D.; Blume, C.; Boca, G.; Bock, F.; Bogdanov, A.; Boldizsár, L.; Bombara, M.; Bonomi, G.; Bonora, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buhler, P.; Buitron, S. A. I.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Caines, H.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Capon, A. A.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Concas, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Costanza, S.; Crkovská, J.; Crochet, P.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Souza, R. D.; Degenhardt, H. F.; Deisting, A.; Deloff, A.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Di Ruzza, B.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Duggal, A. K.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erhardt, F.; Espagnon, B.; Esumi, S.; Eulisse, G.; Eum, J.; Evans, D.; Evdokimov, S.; Fabbietti, L.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Francisco, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gajdosova, K.; Gallio, M.; Galvan, C. D.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Garg, K.; Garg, P.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Gay Ducati, M. B.; Germain, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, A. S.; Gonzalez, V.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Graham, K. L.; Greiner, L.; Grelli, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grion, N.; Gronefeld, J. M.; Grosa, F.; Grosse-Oetringhaus, J. F.; Grosso, R.; Gruber, L.; Grull, F. R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Guzman, I. B.; Haake, R.; Hadjidakis, C.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Hellbär, E.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Herrmann, F.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Hladky, J.; Hohlweger, B.; Horak, D.; Hornung, S.; Hosokawa, R.; Hristov, P.; Hughes, C.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Ippolitov, M.; Irfan, M.; Isakov, V.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacak, B.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jaelani, S.; Jahnke, C.; Jakubowska, M. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jercic, M.; Jimenez Bustamante, R. T.; Jones, P. G.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Ketzer, B.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Khatun, A.; Khuntia, A.; Kielbowicz, M. M.; Kileng, B.; Kim, D.; Kim, D. W.; Kim, D. J.; Kim, H.; Kim, J. S.; Kim, J.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Koyithatta Meethaleveedu, G.; Králik, I.; Kravčáková, A.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kundu, S.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lapidus, K.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lavicka, R.; Lazaridis, L.; Lea, R.; Leardini, L.; Lee, S.; Lehas, F.; Lehner, S.; Lehrbach, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Litichevskyi, V.; Ljunggren, H. M.; Llope, W. J.; Lodato, D. F.; Loenne, P. I.; Loginov, V.; Loizides, C.; Loncar, P.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Lupi, M.; Lutz, T. H.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martinengo, P.; Martinez, J. A. L.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Mastroserio, A.; Mathis, A. M.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzilli, M.; Mazzoni, M. A.; Meddi, F.; Melikyan, Y.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Mhlanga, S.; Miake, Y.; Mieskolainen, M. M.; Mihaylov, D. L.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Mohisin Khan, M.; Montes, E.; Moreira De Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Münning, K.; Munzer, R. H.; Murakami, H.; Murray, S.; Musa, L.; Musinsky, J.; Myers, C. J.; Naik, B.; Nair, R.; Nandi, B. K.; Nania, R.; Nappi, E.; Narayan, A.; Naru, M. U.; Natal da Luz, H.; Nattrass, C.; Navarro, S. R.; Nayak, K.; Nayak, R.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Negrao De Oliveira, R. A.; Nellen, L.; Nesbo, S. V.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Ohlson, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Oravec, M.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Pachmayer, Y.; Pacik, V.; Pagano, D.; Pagano, P.; Paić, G.; Palni, P.; Pan, J.; Pandey, A. K.; Panebianco, S.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, J.; Park, W. J.; Parmar, S.; Passfeld, A.; Pathak, S. P.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.; Peng, X.; Pereira, L. G.; Pereira Da Costa, H.; Peresunko, D.; Perez Lezama, E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Pezzi, R. P.; Piano, S.; Pikna, M.; Pillot, P.; Pimentel, L. O. D. L.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Poppenborg, H.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Pozdniakov, V.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Rana, D. B.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Ratza, V.; Ravasenga, I.; Read, K. F.; Redlich, K.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rodríguez Cahuantzi, M.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Rokita, P. S.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Rotondi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rueda, O. V.; Rui, R.; Russo, R.; Rustamov, A.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Saarinen, S.; Sadhu, S.; Sadovsky, S.; Šafařík, K.; Saha, S. K.; Sahlmuller, B.; Sahoo, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sandoval, A.; Sarkar, D.; Sarkar, N.; Sarma, P.; Sas, M. H. P.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Scheid, H. S.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schmidt, M. O.; Schmidt, M.; Schuchmann, S.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sett, P.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Sheikh, A. I.; Shigaki, K.; Shou, Q.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singhal, V.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Song, J.; Song, M.; Soramel, F.; Sorensen, S.; Sozzi, F.; Spiriti, E.; Sputowska, I.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stankus, P.; Stenlund, E.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Sumowidagdo, S.; Suzuki, K.; Swain, S.; Szabo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thakur, D.; Thakur, S.; Thomas, D.; Tieulent, R.; Tikhonov, A.; Timmins, A. R.; Toia, A.; Tripathy, S.; Trogolo, S.; Trombetta, G.; Trubnikov, V.; Trzaska, W. H.; Trzeciak, B. A.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Umaka, E. N.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vala, M.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vázquez Doce, O.; Vechernin, V.; Veen, A. M.; Velure, A.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Vértesi, R.; Vickovic, L.; Vigolo, S.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Virgili, T.; Vislavicius, V.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Voscek, D.; Vranic, D.; Vrláková, J.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Watanabe, D.; Watanabe, Y.; Weber, M.; Weber, S. G.; Weiser, D. F.; Wessels, J. P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilk, G.; Wilkinson, J.; Willems, G. A.; Williams, M. C. S.; Windelband, B.; Witt, W. E.; Yalcin, S.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yoon, J. H.; Yurchenko, V.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zimmermann, S.; Zinovjev, G.; Zmeskal, J.

2017-07-01

The production of muons from heavy-flavour hadron decays in p-Pb collisions at √{sNN} = 5.02 TeV was studied for 2

Production of muons from heavy-flavour hadron decays in p–Pb collisions at s NN = 5.02   TeV

DOE PAGES

Acharya, S.; Adamová, D.; Aggarwal, M. M.; ...

2017-03-28

The production of muons from heavy-flavour hadron decays in p–Pb collisions at √ sNN = 5.02 TeV was studied for 2< p T <16 GeV/c with the ALICE detector at the CERN LHC. The measurement was performed at forward (p-going direction) and backward (Pb-going direction) rapidity, in the ranges of rapidity in the centre-of-mass system (cms) 2.03 cms <3.53 and –4.46cms <–2.96, respectively. The production cross sections and nuclear modification factors are presented as a function of transverse momentum (p T). At forward rapidity, the nuclear modification factor is compatible with unity while at backward rapidity, in the interval 2.5more » < p T < 3.5 GeV/c, it is above unity by more than 2σ. The ratio of the forward-to-backward production cross sections is also measured in the overlapping interval 2.96<|y cms| < 3.53 and is smaller than unity by 3.7σ in 2.5< p T <3.5 GeV/c. The data are described by model calculations including cold nuclear matter effects.« less

Bootstrap Current for the Edge Pedestal Plasma in a Diverted Tokamak Geometry

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

Koh, S.; Chang, C. S.; Ku, S.

The edge bootstrap current plays a critical role in the equilibrium and stability of the steep edge pedestal plasma. The pedestal plasma has an unconventional and difficult neoclassical property, as compared with the core plasma. It has a narrow passing particle region in velocity space that can be easily modified or destroyed by Coulomb collisions. At the same time, the edge pedestal plasma has steep pressure and electrostatic potential gradients whose scale-lengths are comparable with the ion banana width, and includes a magnetic separatrix surface, across which the topological properties of the magnetic field and particle orbits change abruptly. Amore » driftkinetic particle code XGC0, equipped with a mass-momentum-energy conserving collision operator, is used to study the edge bootstrap current in a realistic diverted magnetic field geometry with a self-consistent radial electric field. When the edge electrons are in the weakly collisional banana regime, surprisingly, the present kinetic simulation confirms that the existing analytic expressions [represented by O. Sauter et al. , Phys. Plasmas 6 , 2834 (1999)] are still valid in this unconventional region, except in a thin radial layer in contact with the magnetic separatrix. The agreement arises from the dominance of the electron contribution to the bootstrap current compared with ion contribution and from a reasonable separation of the trapped-passing dynamics without a strong collisional mixing. However, when the pedestal electrons are in plateau-collisional regime, there is significant deviation of numerical results from the existing analytic formulas, mainly due to large effective collisionality of the passing and the boundary layer trapped particles in edge region. In a conventional aspect ratio tokamak, the edge bootstrap current from kinetic simulation can be significantly less than that from the Sauter formula if the electron collisionality is high. On the other hand, when the aspect ratio is close to unity, the collisional edge bootstrap current can be significantly greater than that from the Sauter formula. Rapid toroidal rotation of the magnetic field lines at the high field side of a tight aspect-ratio tokamak is believed to be the cause of the different behavior. A new analytic fitting formula, as a simple modification to the Sauter formula, is obtained to bring the analytic expression to a better agreement with the edge kinetic simulation results« less

Bootstrap current for the edge pedestal plasma in a diverted tokamak geometry

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

Koh, S.; Choe, W.; Chang, C. S.

The edge bootstrap current plays a critical role in the equilibrium and stability of the steep edge pedestal plasma. The pedestal plasma has an unconventional and difficult neoclassical property, as compared with the core plasma. It has a narrow passing particle region in velocity space that can be easily modified or destroyed by Coulomb collisions. At the same time, the edge pedestal plasma has steep pressure and electrostatic potential gradients whose scale-lengths are comparable with the ion banana width, and includes a magnetic separatrix surface, across which the topological properties of the magnetic field and particle orbits change abruptly. Amore » drift-kinetic particle code XGC0, equipped with a mass-momentum-energy conserving collision operator, is used to study the edge bootstrap current in a realistic diverted magnetic field geometry with a self-consistent radial electric field. When the edge electrons are in the weakly collisional banana regime, surprisingly, the present kinetic simulation confirms that the existing analytic expressions [represented by O. Sauter et al., Phys. Plasmas 6, 2834 (1999)] are still valid in this unconventional region, except in a thin radial layer in contact with the magnetic separatrix. The agreement arises from the dominance of the electron contribution to the bootstrap current compared with ion contribution and from a reasonable separation of the trapped-passing dynamics without a strong collisional mixing. However, when the pedestal electrons are in plateau-collisional regime, there is significant deviation of numerical results from the existing analytic formulas, mainly due to large effective collisionality of the passing and the boundary layer trapped particles in edge region. In a conventional aspect ratio tokamak, the edge bootstrap current from kinetic simulation can be significantly less than that from the Sauter formula if the electron collisionality is high. On the other hand, when the aspect ratio is close to unity, the collisional edge bootstrap current can be significantly greater than that from the Sauter formula. Rapid toroidal rotation of the magnetic field lines at the high field side of a tight aspect-ratio tokamak is believed to be the cause of the different behavior. A new analytic fitting formula, as a simple modification to the Sauter formula, is obtained to bring the analytic expression to a better agreement with the edge kinetic simulation results.« less

Cosmology and the large-mass problem of the five-dimensional Kaluza-Klein theory

NASA Astrophysics Data System (ADS)

Lukács, B.; Pacher, T.

1985-12-01

It is shown that in five-dimensional Kaluza-Klein theories the large-mass problem leads to circulus vitiosus: the huge recent e2/G value produces the large mass problem, which restricts the ratio e2/Gm2 to the order of unity, in contradiction with the present 1040 value for elementary particles.

The Effect of Temperature Dependent Rheology on a Kinematic Model of Continental Breakup and Rifted Continental Margin Formation

NASA Astrophysics Data System (ADS)

Tymms, V. J.; Kusznir, N. J.

2004-12-01

The effect of temperature dependent rheology has been examined for a model of continental lithosphere thinning by an upwelling divergent flow field within continental lithosphere and asthenosphere leading to continental breakup and rifted continental margin formation. The model uses a coupled FE fluid flow and thermal solution and is kinematically driven using a half divergence rate Vx and upwelling velocity Vz. Viscosity structure is modified by the evolving temperature field of the model through the temperature dependent Newtonian rheology. Continental lithosphere and asthenosphere material are advected by the fluid-flow field in order to predict crustal and mantle lithosphere thinning leading to rifted continental margin formation. The results of the temperature dependent rheology model are compared with those of a simple isoviscous model. The temperature dependent rheology model predicts continental lithosphere thinning and depth dependent stretching, similar to that predicted by the uniform viscosity model. However compared with the uniform viscosity model the temperature dependent rheology predicts greater amounts of thinning of the continental crust and lithospheric mantle than the isoviscous solutions. An important parameter within the kinematic model of continental lithosphere breakup and rifted continental margin development is the velocity ratio Vz/Vx. For non-volcanic margins, Vz/Vx is thought to be around unity. Applying a velocity ratio Vz/Vx of unity gives a diffuse ocean-continent transition and exhumation of continental lithospheric mantle. For volcanic margins, Vz/Vx is of order 10, falling to unity with a half-life of order 10 Ma, leading to a more sharply defined ocean-continent transition. While Vx during continental breakup may be estimated, Vz can only be inferred. FE fluid flow solutions, in which Vz is not imposed and without an initial buoyancy driven flow component, predict a velocity ratio Vz/Vx of around unity for both temperature dependent rheology and isovisous fluid-flow solutions. The effect of incorporating a lithology dependent continental lithosphere rheology (quartz-feldspar crust, olivine mantle) with temperature dependence is also being investigated. The work forms part of the Integrated Seismic Imaging and Modelling of Margins (iSIMM*) project. This work forms part of the NERC Margins iSIMM project. iSIMM investigators are from Liverpool and Cambridge Universities, Schlumberger Cambridge Research & Badley Geoscience, supported by the NERC, the DTI, Agip UK, BP, Amerada Hess Ltd, Anadarko, Conoco-Phillips, Shell, Statoil and WesternGeco. The iSIMM team comprises NJ Kusznir, RS White, AM Roberts, PAF Christie, R Spitzer, N Hurst, ZC Lunnon, CJ Parkin, AW Roberts, LK Smith, V Tymms & D. Healy.

The Survey of Vision-based 3D Modeling Techniques

NASA Astrophysics Data System (ADS)

Ruan, Mingzhe

2017-10-01

This paper reviews the vision-based localization and map construction methods from the perspectives of VSLAM, SFM, 3DMax and Unity3D. It focuses on the key technologies and the latest research progress on each aspect, analyzes the advantages and disadvantages of each method, illustrates their implementation process and system framework, and further discusses the way to promote the combination for their complementary strength. Finally, the future opportunity of the combination of the four techniques is expected.

Exchanges...Assessing Their Value: A Summary of the Annual Conference of the Society for Educational Visits and Exchanges in Canada = La valeur des echanges...Une appreciation concrete: un recueil du Congres annuel 1983 de la Societe educative de visites et d'echanges au Canada.

ERIC Educational Resources Information Center

Society for Educational Visits and Exchanges in Canada, Ottawa (Ontario).

The proceedings of the 1983 annual meeting on student and teacher exchanges programs include these papers: "Exchanges...How They Contribute to National Unity and National Identity" (Huguette Labelle); "Exchanges...Bridging the Gap" (Gildas Molgat); "Exchanges...And Canada's Bicultural Aspect" (Dennis Dawson);…

The Organizational Imperative: Theory and History on Unity of Effort in Counterinsurgency Campaigns

DTIC Science & Technology

2010-12-10

project and the time it took away from other things. vi TABLE OF CONTENTS Page MASTER OF MILITARY ART AND SCIENCE THESIS APPROVAL PAGE...inability to manage aspects of the control of the project areas.77 In terms of counterinsurgency theory and the advice of the theorists, it is unclear...MILITARY ART AND SCIENCE Military History by JAN K. GLEIMAN, LTC, USA MPA, Georgetown University, Washington, DC, 2006 M.S., Troy

Thermodynamic Driving Force of Hydrogen on Rumen Microbial Metabolism: A Theoretical Investigation

PubMed Central

van Lingen, Henk J.; Plugge, Caroline M.; Fadel, James G.; Kebreab, Ermias; Bannink, André; Dijkstra, Jan

2016-01-01

Hydrogen is a key product of rumen fermentation and has been suggested to thermodynamically control the production of the various volatile fatty acids (VFA). Previous studies, however, have not accounted for the fact that only thermodynamic near-equilibrium conditions control the magnitude of reaction rate. Furthermore, the role of NAD, which is affected by hydrogen partial pressure (PH2), has often not been considered. The aim of this study was to quantify the control of PH2 on reaction rates of specific fermentation pathways, methanogenesis and NADH oxidation in rumen microbes. The control of PH2 was quantified using the thermodynamic potential factor (FT), which is a dimensionless factor that corrects a predicted kinetic reaction rate for the thermodynamic control exerted. Unity FT was calculated for all glucose fermentation pathways considered, indicating no inhibition of PH2 on the production of a specific type of VFA (e.g., acetate, propionate and butyrate) in the rumen. For NADH oxidation without ferredoxin oxidation, increasing PH2 within the rumen physiological range decreased FT from unity to zero for different NAD+ to NADH ratios and pH of 6.2 and 7.0, which indicates thermodynamic control of PH2. For NADH oxidation with ferredoxin oxidation, increasing PH2 within the rumen physiological range decreased FT from unity at pH of 7.0 only. For the acetate to propionate conversion, FT increased from 0.65 to unity with increasing PH2, which indicates thermodynamic control. For propionate to acetate and butyrate to acetate conversions, FT decreased to zero below the rumen range of PH2, indicating full thermodynamic suppression. For methanogenesis by archaea without cytochromes, FT differed from unity only below the rumen range of PH2, indicating no thermodynamic control. This theoretical investigation shows that thermodynamic control of PH2 on individual VFA produced and associated yield of hydrogen and methane cannot be explained without considering NADH oxidation. PMID:27783615

Signal velocity and group velocity for an optical pulse propagating through a GaAs cavity.

PubMed

Centini, Marco; Bloemer, Mark; Myneni, Krishna; Scalora, Michael; Sibilia, Concita; Bertolotti, Mario; D'Aguanno, Giuseppe

2003-07-01

We present measurements of the signal and group velocities for chirped optical pulses propagating through a GaAs cavity. The signal velocity is based on a specified signal-to-noise ratio at the detector. Under our experimental conditions, the chirp substantially modifies the group velocity of the pulse, but leaves the signal velocity unaltered. At unity transmittance, the velocities are equal. In general, when the transmittance is less than unity, the group velocity is faster than the signal velocity. While the group velocity can be negative, the signal velocity is always less than c/n, where c is the speed of light in vacuum and n is the refractive index of GaAs. To our knowledge, this is the first measurement of both the group velocity and the signal velocity in any system.

Premixed flame propagation in combustible particle cloud mixtures

NASA Technical Reports Server (NTRS)

Seshadri, K.; Yang, B.

1993-01-01

The structures of premixed flames propagating in combustible systems, containing uniformly distributed volatile fuel particles, in an oxidizing gas mixtures is analyzed. The experimental results show that steady flame propagation occurs even if the initial equivalence ratio of the combustible mixture based on the gaseous fuel available in the particles, phi(u) is substantially larger than unity. A model is developed to explain these experimental observations. In the model it is presumed that the fuel particles vaporize first to yield a gaseous fuel of known chemical composition which then reacts with oxygen in a one-step overall process. It is shown that the interplay of vaporization kinetics and oxidation process, can result in steady flame propagation in combustible mixtures where the value of phi(u) is substantially larger than unity. This prediction is in agreement with experimental observations.

Surface temperature effect on subsonic stall.

NASA Technical Reports Server (NTRS)

Macha, J. M.; Norton, D. J.; Young, J. C.

1972-01-01

Results of an analytical and experimental study of boundary layer flow over an aerodynamic surface rejecting heat to a cool environment. This occurs following reentry of a Space Shuttle vehicle. Analytical studies revealed that a surface to freestream temperature ratio, greater than unity tended to destabilize the boundary layer, hastening transition and separation. Therefore, heat transfer accentuated the effect of an adverse pressure gradient. Wind tunnel tests of a 0012-64 NACA airfoil showed that the stall angle was significantly reduced while drag tended to increase for freestream temperature ratios up to 2.2.

Study of immunoglobulins in pleura and pleural effusions.

PubMed Central

Telvi, L; Jaubert, F; Eyquem, A; Andreux, J P; Labrousse, F; Chrétien, J

1979-01-01

The protein concentration of 35 pleural effusions was compared with that in the serum. The ratio of the pleural and serum concentration of albumin, IgG, IgA, and IgM is always below unity and appears to have no diagnostic value. However, the ratio of the concentration of these proteins was inversely related to their molecular weight. The underlying mechanism in malignant and inflammatory effusions appear similar and is in keeping with a diffusion process. Immunofluorescent staining of the pleura suggests the intercellular passage of the proteins through the mesothelial barrier. Images PMID:384578

Complexity vs. unity in unilateral spatial neglect.

PubMed

Rode, G; Fourtassi, M; Pagliari, C; Pisella, L; Rossetti, Y

Unilateral spatial neglect constitutes a heterogeneous syndrome characterized by two main entangled components: a contralesional bias of spatial attention orientation; and impaired building and/or exploration of mental representations of space. These two components are present in different subtypes of unilateral spatial neglect (visual, auditory, somatosensory, motor, allocentric, egocentric, personal, representational and productive manifestations). Detailed anatomical and clinical analyses of these conditions and their underlying disorders show the complexity of spatial cognitive deficits and the difficulty of proposing just one explanation. This complexity is in contrast, however, to the widely acknowledged effectiveness of rehabilitation of the various symptoms and subtypes of unilateral spatial neglect, exemplified in the case of prism adaptation. These common effects are reflections of the unity of the physiotherapeutic mechanisms behind the higher brain functions related to multisensory integration and spatial representations, whereas the paradoxical aspects of unilateral spatial neglect emphasize the need for a greater understanding of spatial cognitive disorders. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Gain in stochastic resonance: Precise numerics versus linear response theory beyond the two-mode approximation

NASA Astrophysics Data System (ADS)

Casado-Pascual, Jesús; Denk, Claus; Gómez-Ordóñez, José; Morillo, Manuel; Hänggi, Peter

2003-03-01

In the context of the phenomenon of stochastic resonance (SR), we study the correlation function, the signal-to-noise ratio (SNR), and the ratio of output over input SNR, i.e., the gain, which is associated to the nonlinear response of a bistable system driven by time-periodic forces and white Gaussian noise. These quantifiers for SR are evaluated using the techniques of linear response theory (LRT) beyond the usually employed two-mode approximation scheme. We analytically demonstrate within such an extended LRT description that the gain can indeed not exceed unity. We implement an efficient algorithm, based on work by Greenside and Helfand (detailed in the Appendix), to integrate the driven Langevin equation over a wide range of parameter values. The predictions of LRT are carefully tested against the results obtained from numerical solutions of the corresponding Langevin equation over a wide range of parameter values. We further present an accurate procedure to evaluate the distinct contributions of the coherent and incoherent parts of the correlation function to the SNR and the gain. As a main result we show for subthreshold driving that both the correlation function and the SNR can deviate substantially from the predictions of LRT and yet the gain can be either larger or smaller than unity. In particular, we find that the gain can exceed unity in the strongly nonlinear regime which is characterized by weak noise and very slow multifrequency subthreshold input signals with a small duty cycle. This latter result is in agreement with recent analog simulation results by Gingl et al. [ICNF 2001, edited by G. Bosman (World Scientific, Singapore, 2002), pp. 545 548; Fluct. Noise Lett. 1, L181 (2001)].

Testing the non-unity of rate ratio under inverse sampling.

PubMed

Tang, Man-Lai; Liao, Yi Jie; Ng, Hong Keung Tony; Chan, Ping Shing

2007-08-01

Inverse sampling is considered to be a more appropriate sampling scheme than the usual binomial sampling scheme when subjects arrive sequentially, when the underlying response of interest is acute, and when maximum likelihood estimators of some epidemiologic indices are undefined. In this article, we study various statistics for testing non-unity rate ratios in case-control studies under inverse sampling. These include the Wald, unconditional score, likelihood ratio and conditional score statistics. Three methods (the asymptotic, conditional exact, and Mid-P methods) are adopted for P-value calculation. We evaluate the performance of different combinations of test statistics and P-value calculation methods in terms of their empirical sizes and powers via Monte Carlo simulation. In general, asymptotic score and conditional score tests are preferable for their actual type I error rates are well controlled around the pre-chosen nominal level, and their powers are comparatively the largest. The exact version of Wald test is recommended if one wants to control the actual type I error rate at or below the pre-chosen nominal level. If larger power is expected and fluctuation of sizes around the pre-chosen nominal level are allowed, then the Mid-P version of Wald test is a desirable alternative. We illustrate the methodologies with a real example from a heart disease study. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

8 CFR 236.18 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 8 Aliens and Nationality 1 2011-01-01 2011-01-01 false Termination of Family Unity Program... REMOVED Family Unity Program § 236.18 Termination of Family Unity Program benefits. (a) Grounds for termination. The Service may terminate benefits under the Family Unity Program whenever the necessity for the...

8 CFR 236.18 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Termination of Family Unity Program... REMOVED Family Unity Program § 236.18 Termination of Family Unity Program benefits. (a) Grounds for termination. The Service may terminate benefits under the Family Unity Program whenever the necessity for the...

Assessment of an apparent relationship between availability of soluble carbohydrates and reduced nitrogen during floral initiation in tobacco

NASA Technical Reports Server (NTRS)

Raper, C. D. Jr; Thomas, J. F.; Tolley-Henry, L.; Rideout, J. W.; Raper CD, J. r. (Principal Investigator)

1988-01-01

Daily relative accumulation rate of soluble carbohydrates (RARS) and reduced nitrogen (RARN) in the shoot, as estimates of source strength, were compared with daily relative growth rates (RGR) of the shoot, as an estimate of sink demand, during floral transformation in apical meristems of tobacco (Nicotiana tabacum 'NC 2326') grown at day/night temperatures of 18/14, 22/18, 26/22, 30/26, and 34/30 C. Source strength was assumed to exceed sink demand for either carbohydrates or nitrogen when the ratio of RARS/RGR or RARN/RGR was greater than unity, and sink demand was assumed to exceed source strength when the ratio was less than unity. Time of floral initiation, which was delayed up to 21 days with increases in temperature over the experimental range, was associated with intervals in which source strength of either carbohydrate or nitrogen exceeded sink demand, while sink demand for the other exceeded source strength. Floral initiation was not observed during intervals in which source strengths of both carbohydrates and nitrogen were greater than or less than sink demand. These results indicate that floral initiation is responsive to an imbalance in the relative availabilities of carbohydrate and nitrogen.

The Ca II V/R ratio and mass loss. [stellar spectral emission lines

NASA Technical Reports Server (NTRS)

Stencel, R. E.

1978-01-01

High-dispersion coude spectrograms of 181 MK standards of types early F through late M, including luminosity classes Ia, Ib, II, and III, are analyzed. It is shown that the brightness ratio of the V and R self-reversed emission peaks (denoted V/R) in the center of the Ca II K line is correlated with spectral type as well as with certain other spectral-type and luminosity-sensitive parameters, including indicators of mass loss and the H-K wing emission lines. The observations indicate that V/R varies smoothly from less than unity in late K and M giants to greater than unity for G giants. This trend appears to be true for bright giants as well but not necessarily for supergiants and seems to hold for the average V/R for a given star, although short-term variations in V/R occur. It is suggested that the V/R values, which can be interpreted in terms of atmospheric motions, may indirectly relate to effects of evolutionary changes in stellar structure and that V/R among late-type stars could be useful as an indicator of both chromospheric activity and the state of stellar evolution.

Vaporization of a solid surface in an ambient gas

NASA Astrophysics Data System (ADS)

Benilov, M. S.; Jacobsson, S.; Kaddani, A.; Zahrai, S.

2001-07-01

The net flux of vapour from a solid surface in an ambient gas is analysed with the aim to estimate the effect of vaporization cooling on the energy balance of an arc cathode under conditions typical for a high-power current breaker. If the ratio of the equilibrium vapour pressure pv to the ambient pressure p∞ is smaller than unity, the removal of vapour from the surface is due to diffusion into the bulk of the gas. As a consequence, the net flux of the vapour from the surface is much smaller than the emitted flux. An estimate of the diffusion rate under conditions typical for a high-power current breaker indicates that vaporization cooling plays a minor role in the energy balance of the cathode in this case. If ratio pv/p∞ is above unity, the flow of the vapour from the surface appears and the net flux is comparable to the emitted flux. A simple analytical solution has been obtained for this case, which is in a good agreement with results of the Monte Carlo modelling of preceding authors. If pv/p∞ exceeds approximately 4.5, vaporization occurs as into vacuum and the net flux is about 0.82 of the emitted flux.

Influence of smooth temperature variation on hotspot ignition

NASA Astrophysics Data System (ADS)

Reinbacher, Fynn; Regele, Jonathan David

2018-01-01

Autoignition in thermally stratified reactive mixtures originates in localised hotspots. The ignition behaviour is often characterised using linear temperature gradients and more recently constant temperature plateaus combined with temperature gradients. Acoustic timescale characterisation of plateau regions has been successfully used to characterise the type of mechanical disturbance that will be created from a plateau core ignition. This work combines linear temperature gradients with superelliptic cores in order to more accurately account for a local temperature maximum of finite size and the smooth temperature variation contained inside realistic hotspot centres. A one-step Arrhenius reaction is used to model a H2-air reactive mixture. Using the superelliptic approach a range of behaviours for temperature distributions are investigated by varying the temperature profile between the gradient only and plateau and gradient bounding cases. Each superelliptic case is compared to a respective plateau and gradient case where simple acoustic timescale characterisation may be performed. It is shown that hot spots equivalent with excitation-to-acoustic timescale ratios sufficiently greater than unity exhibit behaviour very similar to a simple plateau-gradient model. However, for larger hot spots with timescale ratios sufficiently less than unity the reaction behaviour is highly dependent on the smooth temperature profile contained within the core region.

From Georgia to Jerusalem: some Medical Aspects of "The Knight in the Panther's Skin" by Shota Rustaveli.

PubMed

Ohry, Avi; Ohry, Karin; Shemesh, Frida; Shemesh, Gabi

2015-06-01

The Georgian poet Rustaveli wrote his epic poem The Knight in the Panther's Skin around 1200. He knew the works of Hippocrates and Galen, and believed in the unity of body and soul.Thereare many references to health and medicine in the poem, and we shall highlight some of them. In 1185 Rustaveli left Georgia and settled in Jerusalem. There he lived and died at the Monastery of the Cross, where he was buried.

Reduction of Thermal Conductivity by Nanoscale 3D Phononic Crystal

PubMed Central

Yang, Lina; Yang, Nuo; Li, Baowen

2013-01-01

We studied how the period length and the mass ratio affect the thermal conductivity of isotopic nanoscale three-dimensional (3D) phononic crystal of Si. Simulation results by equilibrium molecular dynamics show isotopic nanoscale 3D phononic crystals can significantly reduce the thermal conductivity of bulk Si at high temperature (1000 K), which leads to a larger ZT than unity. The thermal conductivity decreases as the period length and mass ratio increases. The phonon dispersion curves show an obvious decrease of group velocities in 3D phononic crystals. The phonon's localization and band gap is also clearly observed in spectra of normalized inverse participation ratio in nanoscale 3D phononic crystal. PMID:23378898

Comment on 'Controversy concerning the definition of quark and gluon angular momentum' by Elliot Leader [PRD 83, 096012 (2011)

NASA Astrophysics Data System (ADS)

Lin, Huey-Wen; Liu, Keh-Fei

2012-03-01

It is argued by the author that the canonical form of the quark energy-momentum tensor with a partial derivative instead of the covariant derivative is the correct definition for the quark momentum and angular momentum fraction of the nucleon in covariant quantization. Although it is not manifestly gauge-invariant, its matrix elements in the nucleon will be nonvanishing and are gauge-invariant. We test this idea in the path-integral quantization by calculating correlation functions on the lattice with a gauge-invariant nucleon interpolation field and replacing the gauge link in the quark lattice momentum operator with unity, which corresponds to the partial derivative in the continuum. We find that the ratios of three-point to two-point functions are zero within errors for both the u and d quarks, contrary to the case without setting the gauge links to unity.

Understanding fifth-harmonic generation in CLBO

NASA Astrophysics Data System (ADS)

Patankar, S.; Yang, S. T.; Moody, J. D.; Bayramian, A. J.; Swadling, G. F.; Barker, D.; Datte, P.; Mennerat, G.; Norton, M.; Carr, C. W.; Begishev, I. A.; Bromage, J.; Ross, J. S.

2018-02-01

We report on results of fifth harmonic generation in Cesium Lithium Borate (CLBO) using a three-crystal cascaded frequency conversion scheme designed to study the energy balance of the final sum frequency generation stage. The experimental setup independently combines the first and fourth harmonic of a Nd:Glass laser in a 5mm thick CLBO crystal. Energy balance between the incoming and output energy is close to unity when the CLBO is out of phase matching and approximately 80% when the crystal is in phase matching. A detailed analysis of the residual fundamental and fourth harmonic energy indicates 5th harmonic light is being generated but only 26% is unaccounted for. We attribute the missing light to linear transmission loss in the CLBO oven. The ratio of the output to input energy is unity when the missing 5th harmonic is incorporated into the calculations. Two-dimensional plane wave mixing simulations show agreement with the results at lower intensities.

Palm oil: biochemical, physiological, nutritional, hematological, and toxicological aspects: a review.

PubMed

Edem, D O

2002-01-01

The link between dietary fats and cardiovascular diseases has necessitated a growing research interest in palm oil, the second largest consumed vegetable oil in the world. Palm oil, obtained from a tropical plant, Elaeis guineensis contains 50% saturated fatty acids, yet it does not promote atherosclerosis and arterial thrombosis. The saturated fatty acid to unsaturated fatty acid ratio of palm oil is close to unity and it contains a high amount of the antioxidants, beta-carotene, and vitamin E. Although palm oil-based diets induce a higher blood cholesterol level than do corn, soybean, safflower seed, and sunflower oils, the consumption of palm oil causes the endogenous cholesterol level to drop. This phenomenon seems to arise from the presence of the tocotrienols and the peculiar isomeric position of its fatty acids. The benefits of palm oil to health include reduction in risk of arterial thrombosis and atherosclerosis, inhibition of endogenous cholesterol biosynthesis, platelet aggregation, and reduction in blood pressure. Palm oil has been used in the fresh state and/or at various levels of oxidation. Oxidation is a result of processing the oil for various culinary purposes. However, a considerable amount of the commonly used palm oil is in the oxidized state, which poses potential dangers to the biochemical and physiological functions of the body. Unlike fresh palm oil, oxidized palm oil induces an adverse lipid profile, reproductive toxicity and toxicity of the kidney, lung, liver, and heart. This may be as a result of the generation of toxicants brought on by oxidation. In contrast to oxidized palm oil, red or refined palm oil at moderate levels in the diet of experimental animals promotes efficient utilization of nutrients, favorable body weight gains, induction of hepatic drug metabolizing enzymes, adequate hemoglobinization of red cells and improvement of immune function. Howerer, high palm oil levels in the diet induce toxicity to the liver as shown by loss of cellular radial architecture and cell size reductions which are corroborated by alanine transaminase to asparate transaminase ratios which are higher than unity. The consumtion of moderate amounts of palm oil and reduction in the level of oxidation may reduce the health risk believed to be associated with the consumption of palm oil. Red palm oil, by virtue of its beta-carotene content, may protect against vitamin A deficiency and certain forms of cancer.

The Unity connecting module is moved to payload canister

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility, an overhead crane moves the Unity connecting module to the payload canister for transfer to the launch pad. Part of the International Space Station (ISS), Unity is scheduled for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

Particle size variations between bed load and bed material in natural gravel bed channels

Treesearch

Thomas E. Lisle

1995-01-01

Abstract - Particle sizes of bed load and bed material that represent materials transported and stored over a period of years are used to investigate selective transport in 13 previously sampled, natural gravel bed channels. The ratio (D*) of median particle size of bed material to the transport- and frequency-weighted mean of median bed load size decreases to unity...

Fuel Breeding and Core Behavior Analyses on In Core Fuel Management of Water Cooled Thorium Reactors

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

Permana, Sidik; Department of Physics, Bandung Institute of Technology, Gedung Fisika, Jl. Ganesha 10, Bandung 40132; Sekimoto, Hiroshi

2010-12-23

Thorium fuel cycle with recycled U-233 has been widely recognized having some contributions to improve the water-cooled breeder reactor program which has been shown by a feasible area of breeding and negative void reactivity which confirms that fissile of 233U contributes to better fuel breeding and effective for obtaining negative void reactivity coefficient as the main fissile material. The present study has the objective to estimate the effect of whole core configuration as well as burnup effects to the reactor core profile by adopting two dimensional model of fuel core management. About more than 40 months of cycle period hasmore » been employed for one cycle fuel irradiation of three batches fuel system for large water cooled thorium reactors. All position of fuel arrangement contributes to the total core conversion ratio which gives conversion ratio less than unity of at the BOC and it contributes to higher than unity (1.01) at the EOC after some irradiation process. Inner part and central part give the important part of breeding contribution with increasing burnup process, while criticality is reduced with increasing the irradiation time. Feasibility of breeding capability of water-cooled thorium reactors for whole core fuel arrangement has confirmed from the obtained conversion ratio which shows higher than unity. Whole core analysis on evaluating reactivity change which is caused by the change of voided condition has been employed for conservative assumption that 100% coolant and moderator are voided. It obtained always a negative void reactivity coefficient during reactor operation which shows relatively more negative void coefficient at BOC (fresh fuel composition), and it becomes less negative void coefficient with increasing the operation time. Negative value of void reactivity coefficient shows the reactor has good safety properties in relation to the reactivity profile which is the main parameter in term of criticality safety analysis. Therefore, this evaluation has confirmed that breeding condition and negative coefficient can be obtained simultaneously for water-cooled thorium reactor obtains based on the whole core fuel arrangement.« less

'To preserve unity while almost allowing for chaos': Testing the aesthetic principle of unity-in-variety in product design.

PubMed

Post, R A G; Blijlevens, J; Hekkert, P

2016-01-01

Unity-in-variety is considered to be one of the oldest-known universal principles of beauty. However, little empirical research exists on how unity and variety together influence aesthetic appreciation. In three studies we investigated how unity and variety predict the aesthetic appreciation of a range of product designs, and further assessed whether perceived visual complexity and individual differences in regulatory focus influence this relationship. Our findings reveal that both unity and variety, while suppressing each other's effect, positively affect aesthetic appreciation. Hence, product designs that exhibit an optimum balance between unity and variety are aesthetically preferred. Furthermore, the research reveals that unity is the dominant factor in this relationship and facilitates the appreciation of variety. We discuss several theoretical and practical implications resulting from these studies. Copyright © 2015 Elsevier B.V. All rights reserved.

Surface obstacles in pulsatile flow

NASA Astrophysics Data System (ADS)

Carr, Ian A.; Plesniak, Michael W.

2017-11-01

Flows past obstacles mounted on flat surfaces have been widely studied due to their ubiquity in nature and engineering. For nearly all of these studies, the freestream flow over the obstacle was steady, i.e., constant velocity, unidirectional flow. Unsteady, pulsatile flows occur frequently in biology, geophysics, biomedical engineering, etc. Our study is aimed at extending the comprehensive knowledge base that exists for steady flows to considerably more complex pulsatile flows. Characterizing the vortex and wake dynamics of flows around surface obstacles embedded in pulsatile flows can provide insights into the underlying physics in all wake and junction flows. In this study, we experimentally investigate the wake of two canonical obstacles: a cube and a circular cylinder with an aspect ratio of unity. Our previous studies of a surface-mounted hemisphere in pulsatile flow are used as a baseline for these two new, more complex geometries. Phase-averaged PIV and hot-wire anemometry are used to characterize the dynamics of coherent structures in the wake and at the windward junction of the obstacles. Complex physics occur during the deceleration phase of the pulsatile inflow. We propose a framework for understanding these physics based on self-induced vortex propagation, similar to the phenomena exhibited by vortex rings.

The unique radar scattering properties of silicic lava flows and domes

NASA Technical Reports Server (NTRS)

Plaut, Jeffrey J.; Stofan, Ellen R.; Anderson, Steven W.; Crown, David A.

1995-01-01

Silicic (silica-rich) lava flows, such as rhyolite, rhyodacite, and dacite, possess unique physical properties primarily because of the relatively high viscosity of the molten lava. Silicic flows tend to be thicker than basaltic flows, and the resulting large-scale morphology is typically a steep-sided dome or flow lobe, with aspect ratios (height/length) sometimes approaching unity. The upper surfaces of silicic domes and flows are normally emplaced as relatively cool, brittle slabs that fracture as they are extruded from the central vent areas, and are then rafted away toward the flow margin as a brittle carapace above a more ductile interior layer. This mode of emplacement results in a surface with unique roughness characteristics, which can be well-characterized by multiparameter synthetic aperture radar (SAR) observations. In this paper, we examine the scattering properties of several silicic domes in the Inyo volcanic chain in the Eastern Sierra of California, using AIRSAR and TOPSAR data. Field measurements of intermediate-scale (cm to tens of m) surface topography and block size are used to assess the mechanisms of the scattering process, and to quantify the unique roughness characteristics of the flow surfaces.

Experience with Round Beam Operation at The Advanced Photon Source

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

Xiao, A.; Emery, L.; Sajaev, V.

2015-01-01

Very short Touschek lifetime becomes a common issue for next-generation ultra-low emittance storage ring light sources. In order to reach a longer beamlifetime, such amachine often requires operating with a vertical-to-horizontal emittance ratio close to an unity, i.e. a “round beam”. In tests at the APS storage ring, we determined how a round beam can be reached experimentally. Some general issues, such as beam injection, optics measurement and corrections, and orbit correction have been tested also. To demonstrate that a round beam was achieved, the beam size ratio is calibrated using beam lifetime measurement.

The Effect of Cooling Passage Aspect Ratio on Curvature Heat Transfer Enhancement

NASA Technical Reports Server (NTRS)

Meyer, Michael L.

1997-01-01

A series of electrically heated tube experiments was performed to investigate the effect of high aspect ratio on curvature heat transfer enhancement in uniformly heated rectangular cooling passages. Three hardware geometries were tested: a baseline straight aspect ratio 10 tube, an aspect ratio 1 (square) tube with a 45 deg. curve, and an aspect ratio 10 tube with a 45 deg. curve. Gaseous nitrogen with the following properties was used as the coolant: ambient inlet temperature, pressures to 8.3 MPa, wall-to-bulk temperature ratios less than two, and Reynolds numbers based on hydraulic diameter ranging from 250,000 to 1,600,000. The measured curvature enhancement factors were compared to values predicted by three previously published models which had been developed for low aspect ratio tubes. The models were shown to be valid for the high aspect ratio tube as well the low aspect ratio tube, indicating that aspect ratio had little impact on the curvature heat transfer enhancement in these tests.

Measurement of polarization-transfer to bound protons in carbon and its virtuality dependence

NASA Astrophysics Data System (ADS)

Izraeli, D.; Brecelj, T.; Achenbach, P.; Ashkenazi, A.; Böhm, R.; Cohen, E. O.; Distler, M. O.; Esser, A.; Gilman, R.; Kolar, T.; Korover, I.; Lichtenstadt, J.; Mardor, I.; Merkel, H.; Mihovilovič, M.; Müller, U.; Olivenboim, M.; Piasetzky, E.; Ron, G.; Schlimme, B. S.; Schoth, M.; Sfienti, C.; Širca, S.; Štajner, S.; Strauch, S.; Thiel, M.; Weber, A.; Yaron, I.; A1 Collaboration

2018-06-01

We measured the ratio Px /Pz of the transverse to longitudinal components of polarization transferred from electrons to bound protons in 12C by the 12C (e → ,e‧ p →) process at the Mainz Microtron (MAMI). We observed consistent deviations from unity of this ratio normalized to the free-proton ratio, (Px /Pz) 12C /(Px /Pz) 1H, for both s- and p-shell knocked out protons, even though they are embedded in averaged local densities that differ by about a factor of two. The dependence of the double ratio on proton virtuality is similar to the one for knocked out protons from 2H and 4He, suggesting a universal behavior. It further implies no dependence on average local nuclear density.

Unity nameplate is attached to module for ISS and Mission STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

- In the Space Station Processing Facility, a worker checks placement of the nameplate to be attached to the Unity connecting module, part of the International Space Station. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

Unity nameplate added to module for ISS and Mission STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility, workers look over the Unity connecting module, part of the International Space Station, after attaching the nameplate. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

The Unity connecting module is moved to payload canister

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility, workers at the side and on the floor of the payload canister guide the Unity connecting module into position for transfer to the launch pad. Part of the International Space Station (ISS), Unity is scheduled for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

Unity nameplate examined after being attached to module for ISS and Mission STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility, a worker checks placement of the nameplate for the Unity connecting module, part of the International Space Station. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

Unity nameplate is attached to module for ISS and Mission STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

- In the Space Station Processing Facility, a worker places the nameplate on the side of the Unity connecting module, part of the International Space Station. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

The Unity connecting module is moved to payload canister

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility, workers attach the overhead crane that will lift the Unity connecting module from its workstand to move the module to the payload canister. Part of the International Space Station (ISS), Unity is scheduled for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

The Unity connecting module is moved to payload canister

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility, a closeup view shows the overhead crane holding the Unity connecting module as it moves it to the payload canister for transfer to the launch pad. Part of the International Space Station (ISS), Unity is scheduled for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

Fluence correction factors for graphite calorimetry in a low-energy clinical proton beam: I. Analytical and Monte Carlo simulations.

PubMed

Palmans, H; Al-Sulaiti, L; Andreo, P; Shipley, D; Lühr, A; Bassler, N; Martinkovič, J; Dobrovodský, J; Rossomme, S; Thomas, R A S; Kacperek, A

2013-05-21

The conversion of absorbed dose-to-graphite in a graphite phantom to absorbed dose-to-water in a water phantom is performed by water to graphite stopping power ratios. If, however, the charged particle fluence is not equal at equivalent depths in graphite and water, a fluence correction factor, kfl, is required as well. This is particularly relevant to the derivation of absorbed dose-to-water, the quantity of interest in radiotherapy, from a measurement of absorbed dose-to-graphite obtained with a graphite calorimeter. In this work, fluence correction factors for the conversion from dose-to-graphite in a graphite phantom to dose-to-water in a water phantom for 60 MeV mono-energetic protons were calculated using an analytical model and five different Monte Carlo codes (Geant4, FLUKA, MCNPX, SHIELD-HIT and McPTRAN.MEDIA). In general the fluence correction factors are found to be close to unity and the analytical and Monte Carlo codes give consistent values when considering the differences in secondary particle transport. When considering only protons the fluence correction factors are unity at the surface and increase with depth by 0.5% to 1.5% depending on the code. When the fluence of all charged particles is considered, the fluence correction factor is about 0.5% lower than unity at shallow depths predominantly due to the contributions from alpha particles and increases to values above unity near the Bragg peak. Fluence correction factors directly derived from the fluence distributions differential in energy at equivalent depths in water and graphite can be described by kfl = 0.9964 + 0.0024·zw-eq with a relative standard uncertainty of 0.2%. Fluence correction factors derived from a ratio of calculated doses at equivalent depths in water and graphite can be described by kfl = 0.9947 + 0.0024·zw-eq with a relative standard uncertainty of 0.3%. These results are of direct relevance to graphite calorimetry in low-energy protons but given that the fluence correction factor is almost solely influenced by non-elastic nuclear interactions the results are also relevant for plastic phantoms that consist of carbon, oxygen and hydrogen atoms as well as for soft tissues.

Mechanical properties of the human hand digits: Age-related differences

PubMed Central

Park, Jaebum; Pazin, Nemanja; Friedman, Jason; Zatsiorsky, Vladimir M.; Latash, Mark L.

2014-01-01

Background Mechanical properties of human digits may have significant implications for the hand function. We quantified several mechanical characteristics of individual digits in young and older adults. Methods Digit tip friction was measured at several normal force values using a method of induced relative motion between the digit tip and the object surface. A modified quick-release paradigm was used to estimate digit apparent stiffness, damping, and inertial parameters. The subjects grasped a vertical handle instrumented with force/moment sensors using a prismatic grasp with four digits; the handle was fixed to the table. Unexpectedly, one of the sensors yielded leading to a quick displacement of the corresponding digit. A second-order, linear model was used to fit the force/displacement data. Findings Friction of the digit pads was significantly lower in older adults. The apparent stiffness coefficient values were higher while the damping coefficients were lower in older adults leading to lower damping ratio. The damping ratio was above unity for most data in young adults and below unity for older adults. Quick release of a digit led to force changes in other digits of the hand, likely due to inertial hand properties. These phenomena of “mechanical enslaving” were smaller in older adults although no significant difference was found in the inertial parameter in the two groups. Interpretations The decreased friction and damping ratio present challenges for the control of everyday prehensile tasks. They may lead to excessive digit forces and low stability of the grasped object. PMID:24355703

Relationship between BaTiO₃ nanowire aspect ratio and the dielectric permittivity of nanocomposites.

PubMed

Tang, Haixiong; Zhou, Zhi; Sodano, Henry A

2014-04-23

The aspect ratio of barium titanate (BaTiO3) nanowires is demonstrated to be successfully controlled by adjusting the temperature of the hydrothermal growth from 150 to 240 °C, corresponding to aspect ratios from 9.3 to 45.8, respectively. Polyvinylidene fluoride (PVDF) nanocomposites are formed from the various aspect ratio nanowires and the relationship between the dielectric constant of the nanocomposite and the aspect ratio of the fillers is quantified. It was found that the dielectric constant of the nanocomposite increases with the aspect ratio of the nanowires. Nanocomposites with 30 vol % BaTiO3 nanowires and an aspect ratio of 45.8 can reach a dielectric constant of 44.3, which is 30.7% higher than samples with an aspect ratio of 9.3 and 352% larger than the polymer matrix. These results demonstrate that using high-aspect-ratio nanowires is an effective way to control and improve the dielectric performance of nanocomposites for future capacitor applications.

Unity nameplate gets final check before being attached to module for ISS and Mission STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

- In the Space Station Processing Facility, workers make a final check of the nameplate to be attached to the Unity connecting module, part of the International Space Station. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

Unity nameplate examined after being attached to module for ISS and Mission STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility, Joan Higgenbotham, with KSC's Astronaut Office Computer Support, checks placement of the nameplate for the Unity connecting module, part of the International Space Station. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

Influence of smooth temperature variation on hotspot ignition

DOE PAGES

Reinbacher, Fynn; Regele, Jonathan David

2017-10-06

Autoignition in thermally stratified reactive mixtures originates in localised hotspots. The ignition behaviour is often characterised using linear temperature gradients and more recently constant temperature plateaus combined with temperature gradients. Acoustic timescale characterisation of plateau regions has been successfully used to characterise the type of mechanical disturbance that will be created from a plateau core ignition. This work combines linear temperature gradients with superelliptic cores in order to more accurately account for a local temperature maximum of finite size and the smooth temperature variation contained inside realistic hotspot centres. A one-step Arrhenius reaction is used to model a H 2–airmore » reactive mixture. Using the superelliptic approach a range of behaviours for temperature distributions are investigated by varying the temperature profile between the gradient only and plateau and gradient bounding cases. Each superelliptic case is compared to a respective plateau and gradient case where simple acoustic timescale characterisation may be performed. It is shown that hot spots equivalent with excitation-to-acoustic timescale ratios sufficiently greater than unity exhibit behaviour very similar to a simple plateau-gradient model. Furthermore, for larger hot spots with timescale ratios sufficiently less than unity the reaction behaviour is highly dependent on the smooth temperature profile contained within the core region.« less

Influence of smooth temperature variation on hotspot ignition

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

Reinbacher, Fynn; Regele, Jonathan David

Autoignition in thermally stratified reactive mixtures originates in localised hotspots. The ignition behaviour is often characterised using linear temperature gradients and more recently constant temperature plateaus combined with temperature gradients. Acoustic timescale characterisation of plateau regions has been successfully used to characterise the type of mechanical disturbance that will be created from a plateau core ignition. This work combines linear temperature gradients with superelliptic cores in order to more accurately account for a local temperature maximum of finite size and the smooth temperature variation contained inside realistic hotspot centres. A one-step Arrhenius reaction is used to model a H 2–airmore » reactive mixture. Using the superelliptic approach a range of behaviours for temperature distributions are investigated by varying the temperature profile between the gradient only and plateau and gradient bounding cases. Each superelliptic case is compared to a respective plateau and gradient case where simple acoustic timescale characterisation may be performed. It is shown that hot spots equivalent with excitation-to-acoustic timescale ratios sufficiently greater than unity exhibit behaviour very similar to a simple plateau-gradient model. Furthermore, for larger hot spots with timescale ratios sufficiently less than unity the reaction behaviour is highly dependent on the smooth temperature profile contained within the core region.« less

Boscovich: scientist and man of letters

NASA Astrophysics Data System (ADS)

Proverbio, E.

Ruggiero Giuseppe Boscovich (1711-1781) is known as one of the most important scientists of the second half of XVIII century, but he was active also as a man of letters, especially through an abundant production of poems in Latin verse. We try to interpret these two, apparently antinomic, aspects of his character in the framework of the culture of his epoch, in which science and literary productions were not considered as two separate or opposite fields, but only two different aspects of human knowledge. In particular we review the field of his poetic production in which this fundamental unity of knowledge is most evident, namely his poems with didactic-scientific subjects, which are examples of high-level popularization of the latest progresses in science (in particular astronomy and Newtonian physics) by means of elegant Latin verse.

Inhibitory effects of psychotropic drugs on the acetylcholine receptor-operated potassium current (IK.ACh) in guinea-pig atrial myocytes.

PubMed

Okada, Muneyoshi; Watanabe, Shinya; Matada, Takashi; Asao, Yoko; Hamatani, Ramu; Yamawaki, Hideyuki; Hara, Yukio

2013-01-01

Influences of psychotropic drugs, six antipsychotics and three antidepressants, on acetylcholine receptor-operated potassium current (IK.ACh) were examined by a whole-cell patch clamp method in freshly isolated guinea-pig atrial myocyte. IK.ACh was induced by a superfusion of carbachol (CCh) or by an intracellular application of guanosine 5'-[thio] triphosphate (GTPγS). To elucidate mechanism for anticholinergic action, IC50 ratio, the ratio of IC50 for GTPγS-activated IK.ACh to CCh-induced IK.ACh, was calculated. Antipsychotics and antidepressants inhibited CCh-induced IK.ACh in a concentration-dependent manner. The IC50 values were as follows; chlorpromazine 0.53 μM, clozapine 0.06 μM, fluphenazine 2.69 μM, haloperidol 2.66 μM, sulpiride 42.3 μM, thioridazine 0.07 μM, amitriptyline 0.03 μM, imipramine 0.22 μM and maprotiline 1.81 μM. The drugs, except for sulpiride, inhibited GTPγS-activated IK.ACh with following IC50 values; chlorpromazine 1.71 μM, clozapine 14.9 μM, fluphenazine 3.55 μM, haloperidol 2.73 μM, thioridazine 1.90 μM, amitriptyline 7.55 μM, imipramine 7.09 μM and maprotiline 5.93 μM. The IC50 ratio for fluphenazine and haloperidol was close to unity. The IC50 ratio for chlorpromazine, clozapine, thioridazine, amitriptyline, imipramine and maprotiline was much higher than unity. The present findings suggest that the psychotropics studied suppress IK.ACh. Chlorpromazine, clozapine, thioridazine, amitriptyline, imipramine, maprotiline and sulpiride are preferentially acting on muscarinic receptor. Fluphenazine and haloperidol may act on G protein and/or potassium channel.

An 'unconditional-like' structure for the conditional estimator of odds ratio from 2 x 2 tables.

PubMed

Hanley, James A; Miettinen, Olli S

2006-02-01

In the estimation of the odds ratio (OR), the conditional maximum-likelihood estimate (cMLE) is preferred to the more readily computed unconditional one (uMLE). However, the exact cMLE does not have a closed form to help divine it from the uMLE or to understand in what circumstances the difference between the two is appreciable. Here, the cMLE is shown to have the same 'ratio of cross-products' structure as its unconditional counterpart, but with two of the cell frequencies augmented, so as to shrink the unconditional estimator towards unity. The augmentation involves a factor, similar to the finite population correction, derived from the minimum of the marginal totals.

The Unity connecting module moves into payload bay of Endeavour

NASA Technical Reports Server (NTRS)

1998-01-01

The Unity connecting module is moved toward the payload bay of the orbiter Endeavour at Launch Pad 39A. Part of the International Space Station (ISS), Unity is scheduled for launch Dec. 3, 1998, on Mission STS-88 . The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach it to the Russian-built Zarya control module which will be in orbit at that time.

KSC-98pc1411

NASA Image and Video Library

1998-10-22

In the Space Station Processing Facility, an overhead crane moves the Unity connecting module to the payload canister for transfer to the launch pad. Part of the International Space Station (ISS), Unity is scheduled for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time

Core compressor exit stage study, 2

NASA Technical Reports Server (NTRS)

Behlke, R. F.; Burdsall, E. A.; Canal, E., Jr.; Korn, N. D.

1979-01-01

A total of two three-stage compressors were designed and tested to determine the effects of aspect ratio on compressor performance. The first compressor was designed with an aspect ratio of 0.81; the other, with an aspect ratio of 1.22. Both compressors had a hub-tip ratio of 0.915, representative of the rear stages of a core compressor, and both were designed to achieve a 15.0% surge margin at design pressure ratios of 1.357 and 1.324, respectively, at a mean wheel speed of 167 m/sec. At design speed the 0.81 aspect ratio compressor achieved a pressure ratio of 1.346 at a corrected flow of 4.28 kg/sec and an adiabatic efficiency of 86.1%. The 1.22 aspect ratio design achieved a pressure ratio of 1.314 at 4.35 kg/sec flow and 87.0% adiabatic efficiency. Surge margin to peak efficiency was 24.0% with the lower aspect ratio blading, compared with 12.4% with the higher aspect ratio blading.

Unity nameplate examined before being attached to module for ISS and Mission STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility, holding the nameplate for the Unity connecting module are (left) Joan Higginbotham, with the Astronaut Office Computer Support Branch, and (right) Nancy Tolliver, with Boeing-Huntsville. Part of the International Space Station, Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

Unity connecting module in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility, the Unity connecting module, part of the International Space Station, is shown with Pressurized Mating Adapters 1 (left) and 2 (right) attached. Unity is scheduled to undergo testing of the common berthing mechanism to which other space station elements will dock. Unity is the primary payload on mission STS-88, targeted to launch Dec. 3, 1998. Other testing includes the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27. The Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time.

8 CFR 245a.37 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2012 CFR

2012-01-01

... or her ineligible for Family Unity benefits under the LIFE Act Amendments; (3) The alien, upon whose...) A qualifying relationship to the alien, upon whose status Family Unity benefits under the LIFE Act... 8 Aliens and Nationality 1 2012-01-01 2012-01-01 false Termination of Family Unity Program...

8 CFR 245a.37 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) The alien, upon whose status Family Unity benefits under the LIFE Act were based, fails to apply for... Unity benefits under the LIFE Act Amendments shall render the alien amenable to removal under any ground... 8 Aliens and Nationality 1 2011-01-01 2011-01-01 false Termination of Family Unity Program...

8 CFR 245a.37 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) The alien, upon whose status Family Unity benefits under the LIFE Act were based, fails to apply for... Unity benefits under the LIFE Act Amendments shall render the alien amenable to removal under any ground... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Termination of Family Unity Program...

8 CFR 245a.37 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2013 CFR

2013-01-01

... or her ineligible for Family Unity benefits under the LIFE Act Amendments; (3) The alien, upon whose...) A qualifying relationship to the alien, upon whose status Family Unity benefits under the LIFE Act... 8 Aliens and Nationality 1 2013-01-01 2013-01-01 false Termination of Family Unity Program...

8 CFR 245a.37 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2014 CFR

2014-01-01

... or her ineligible for Family Unity benefits under the LIFE Act Amendments; (3) The alien, upon whose...) A qualifying relationship to the alien, upon whose status Family Unity benefits under the LIFE Act... 8 Aliens and Nationality 1 2014-01-01 2014-01-01 false Termination of Family Unity Program...

An optoelectric professional's training model based on Unity of Knowing and Doing theory

NASA Astrophysics Data System (ADS)

Qin, Shiqiao; Wu, Wei; Zheng, Jiaxing; Wang, Xingshu; Zhao, Yingwei

2017-08-01

The "Unity of Knowing and Doing" (UKD) theory is proposed by an ancient Chinese philosopher, Wang Shouren, in 1508, which explains how to unify knowledge and practice. Different from the Chinese traditional UKD theory, the international higher education usually treats knowledge and practice as independent, and puts more emphasis on knowledge. Oriented from the UKD theory, the College of Opto-electric Science and Engineering (COESE) at National University of Defense Technology (NUDT) explores a novel training model in cultivating opto-electric professionals from the aspects of classroom teaching, practice experiment, system experiment, design experiment, research experiment and innovation experiment (CPSDRI). This model aims at promoting the unity of knowledge and practice, takes how to improve the students' capability as the main concern and tries to enhance the progress from cognition to professional action competence. It contains two hierarchies: cognition (CPS) and action competence (DRI). In the cognition hierarchy, students will focus on learning and mastering the professional knowledge of optics, opto-electric technology, laser, computer, electronics and machine through classroom teaching, practice experiment and system experiment (CPS). Great attention will be paid to case teaching, which links knowledge with practice. In the action competence hierarchy, emphasis will be placed on promoting students' capability of using knowledge to solve practical problems through design experiment, research experiment and innovation experiment (DRI). In this model, knowledge is divided into different modules and capability is cultivated on different levels. It combines classroom teaching and experimental teaching in a synergetic way and unifies cognition and practice, which is a valuable reference to the opto-electric undergraduate professionals' cultivation.

Chronic lymphatic leukaemia and engine exhausts, fresh wood, and DDT: a case-referent study.

PubMed Central

Flodin, U; Fredriksson, M; Persson, B; Axelson, O

1988-01-01

The effect of potential risk factors for chronic lymphatic leukaemia was evaluated in a case-referent study encompassing 111 cases and 431 randomised referents, all alive. Information on exposure was obtained by questionnaires posted to the subjects. Crude rate ratios were increased for occupational exposure to solvents. DDT, engine exhausts, fresh wood (lumberjacks, paper pulp workers, and sawmill workers, for example) and also in farming. Further analysis of the material by means of the Miettinen confounder score technique reduced the number of rate ratios significantly exceeding unity to encompass only occupational exposure to engine exhaust, fresh wood, DDT, and contact with horses. PMID:2449239

Standard deviation of scatterometer measurements from space.

NASA Technical Reports Server (NTRS)

Fischer, R. E.

1972-01-01

The standard deviation of scatterometer measurements has been derived under assumptions applicable to spaceborne scatterometers. Numerical results are presented which show that, with sufficiently long integration times, input signal-to-noise ratios below unity do not cause excessive degradation of measurement accuracy. The effects on measurement accuracy due to varying integration times and changing the ratio of signal bandwidth to IF filter-noise bandwidth are also plotted. The results of the analysis may resolve a controversy by showing that in fact statistically useful scatterometer measurements can be made from space using a 20-W transmitter, such as will be used on the S-193 experiment for Skylab-A.

METHOD OF SUSTAINING A NEUTRONIC CHAIN REACTING SYSTEM

DOEpatents

Fermi, E.; Leverett, M.C.

1957-11-12

This patent relates to neutronic reactors and a method of sustainlng a chain reaction. The reactor shown in the patent for carrying out the method is the gas-cooled type comprised of a solid moderator having a plurality of passages therethrough for receiving bodies of fissionable material. In carrying out the method, the reactor is loaded by inserting in the passages fuel elements and moderator material in a proportion to sustain a chain reaction As the reproduction ratio decreases below the desired fiiaire due to impurities formed during operation of the reactor, the moderator material is gradually replaced with additional fuel material to maintain the reproduction ratio above unity.

37 CFR 1.499 - Unity of invention during the national stage.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Unity of invention during the... Provisions National Stage § 1.499 Unity of invention during the national stage. If the examiner finds that a national stage application lacks unity of invention under § 1.475, the examiner may in an Office action...

The Unity connecting module moves into payload bay of Endeavour

NASA Technical Reports Server (NTRS)

1998-01-01

Looking like a painting, this wide-angle view shows the Unity connecting module being moved toward the payload bay of the orbiter Endeavour at Launch Pad 39A. Part of the International Space Station (ISS), Unity is scheduled for launch Dec. 3, 1998, on Mission STS-88. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach it to the Russian-built Zarya control module which will be in orbit at that time.

The Unity connecting module moves into payload bay of Endeavour

NASA Technical Reports Server (NTRS)

1998-01-01

Viewed from below, the Unity connecting module is moved into the payload bay of the orbiter Endeavour at Launch Pad 39A. Part of the International Space Station (ISS), Unity is scheduled for launch Dec. 3, 1998, on Mission STS-88. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach it to the Russian-built Zarya control module which will be in orbit at that time.

KSC-98pc1363

NASA Image and Video Library

1998-10-22

In the Space Station Processing Facility, a worker checks placement of the nameplate for the Unity connecting module, part of the International Space Station. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time

KSC-98pc1367

NASA Image and Video Library

1998-10-22

In the Space Station Processing Facility, a worker checks placement of the nameplate to be attached to the Unity connecting module, part of the International Space Station. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time

KSC-98pc1410

NASA Image and Video Library

1998-10-22

In the Space Station Processing Facility, workers attach the overhead crane that will lift the Unity connecting module from its workstand to move the module to the payload canister. Part of the International Space Station (ISS), Unity is scheduled for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time

KSC-98pc1365

NASA Image and Video Library

1998-10-22

In the Space Station Processing Facility, workers look over the Unity connecting module, part of the International Space Station, after attaching the nameplate. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time

KSC-98pc1366

NASA Image and Video Library

1998-10-22

In the Space Station Processing Facility, workers make a final check of the nameplate to be attached to the Unity connecting module, part of the International Space Station. Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time

KSC-98pc1412

NASA Image and Video Library

1998-10-22

In the Space Station Processing Facility, a closeup view shows the overhead crane holding the Unity connecting module as it moves it to the payload canister for transfer to the launch pad. Part of the International Space Station (ISS), Unity is scheduled for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time

KSC-98pc1413

NASA Image and Video Library

1998-10-22

In the Space Station Processing Facility, workers at the side and on the floor of the payload canister guide the Unity connecting module into position for transfer to the launch pad. Part of the International Space Station (ISS), Unity is scheduled for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time

Unity nameplate examined before being attached to module for ISS and Mission STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

Examining the nameplate for the Unity connecting module, in the Space Station Processing Facility, are (left to right) Joe Schweiger and Tommy Annis, of Boeing-KSC, and Nancy Tolliver, of Boeing-Huntsville. An unidentified worker behind them looks on. Part of the International Space Station, Unity was expected to be transported to Launch Pad 39A on Oct. 26 for launch aboard Space Shuttle Endeavour on Mission STS-88 in December. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach Unity to the Russian-built Zarya control module which will be in orbit at that time.

Experimental analysis for fabrication of high-aspect-ratio piezoelectric ceramic structure by micro-powder injection molding process

NASA Astrophysics Data System (ADS)

Han, Jun Sae; Gal, Chang Woo; Park, Jae Man; Kim, Jong Hyun; Park, Seong Jin

2018-04-01

Aspect ratio effects in the micro-powder injection molding process were experimentally analyzed for fabrication of high-aspect-ratio piezoelectric ceramic structure. The mechanisms of critical defects have been studied according to individual manufacturing steps. In the molding process, incomplete filling phenomenon determines the critical aspect ratios of a micro pattern. According to mold temperature, an incomplete filling phenomenon has been analyzed with respect to different pattern sizes and aspect ratio. In demolding and drying process, the capillary behavior of sacrificial polymeric mold insert determines the critical aspect ratio of a micro pattern. With respect to pattern dimensions, slumping behavior has been analyzed. Based on our current systems, micro PZT feature has stability when it has lower aspect ratio than 5. Under optimized processing conditions, 20 μm and 40 μm ceramic rod array feature which has 5 of aspect ratio were successfully fabricated by the developed process. Further modification points to fabricate the smaller and higher feature were specifically addressed.

Fracture analysis of ductile materials

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.

1980-01-01

In the present paper, Newman's (1973) two-parameter fracture criterion is used to analyze failure of single-edge-crack tension specimens made of bolting steel and rotor steel, with thicknesses and widths of the same order. It is shown that for width-to-thickness ratios of roughly unity, the plastic-collapse stress is strongly influenced by the state of stress on the net section and the collapse stress is closer to the plane-strain value.

Recent Development on O(+) - O Collision Frequency and Ionosphere-Thermosphere Coupling

NASA Technical Reports Server (NTRS)

Omidvar, K.; Menard, R.

1999-01-01

The collision frequency between an oxygen atom and its singly charged ion controls the momentum transfer between the ionosphere and the thermosphere. There has been a long standing discrepancy, extending over a decade, between the theoretical and empirical determination of this frequency: the empirical value of this frequency exceeded the theoretical value by a factor of 1.7. Recent improvements in theory were obtained by using accurate oxygen ion-oxygen atom potential energy curves, and partial wave quantum mechanical calculations. We now have applied three independent statistical methods to the observational data, obtained at the MIT/Millstone Hill Observatory, consisting of two sets A and B. These methods give results consistent with each other, and together with the recent theoretical improvements, bring the ratio close to unity, as it should be. The three statistical methods lead to an average for the ratio of the empirical to the theoretical values equal to 0.98, with an uncertainty of +/-8%, resolving the old discrepancy between theory and observation. The Hines statistics, and the lognormal distribution statistics, both give lower and upper bounds for the Set A equal to 0.89 and 1.02, respectively. The related bounds for the Set B are 1.06 and 1.17. The average values of these bounds thus bracket the ideal value of the ratio which should be equal to unity. The main source of uncertainties are errors in the profile of the oxygen atom density, which is of the order of 11%. An alternative method to find the oxygen atom density is being suggested.

Kinetic effects on the velocity-shear-driven instability

NASA Technical Reports Server (NTRS)

Wang, Z.; Pritchett, P. L.; Ashour-Abdalla, M.

1992-01-01

A comparison is made between the properties of the low-frequency long-wavelength velocity-shear-driven instability in kinetic theory and magnetohydrodynamics (MHD). The results show that the removal of adiabaticity along the magnetic field line in kinetic theory leads to modifications in the nature of the instability. Although the threshold for the instability in the two formalisms is the same, the kinetic growth rate and the unstable range in wave-number space can be larger or smaller than the MHD values depending on the ratio between the thermal speed, Alfven speed, and flow speed. When the thermal speed is much larger than the flow speed and the flow speed is larger than the Alfven speed, the kinetic formalism gives a larger maximum growth rate and broader unstable range in wave-number space. In this regime, the normalized wave number for instability can be larger than unity, while in MHD it is always less than unity. The normal mode profile in the kinetic case has a wider spatial extent across the shear layer.

Centrality-Dependent Modification of Jet-Production Rates in Deuteron-Gold Collisions at √{sN N }=200 GeV

NASA Astrophysics Data System (ADS)

Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Al-Bataineh, H.; Alexander, J.; Alfred, M.; Angerami, A.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Baksay, G.; Baksay, L.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bassalleck, B.; Basye, A. T.; Bathe, S.; Baublis, V.; Baumann, C.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belikov, S.; Belmont, R.; Bennett, R.; Berdnikov, A.; Berdnikov, Y.; Bhom, J. H.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Butsyk, S.; Campbell, S.; Caringi, A.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chung, P.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Conesa Del Valle, Z.; Connors, M.; Csanád, M.; Csörgő, T.; Dahms, T.; Dairaku, S.; Danchev, I.; Danley, T. W.; Das, K.; Datta, A.; Daugherity, M. S.; David, G.; Dayananda, M. K.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dharmawardane, K. V.; Dietzsch, O.; Dion, A.; Diss, P. B.; Do, J. H.; Donadelli, M.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; Dutta, D.; Edwards, S.; Efremenko, Y. V.; Ellinghaus, F.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fujiwara, K.; Fukao, Y.; Fusayasu, T.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, H.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grim, G.; Grosse Perdekamp, M.; Gunji, T.; Gustafsson, H.-Å.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamblen, J.; Hamilton, H. F.; Han, R.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; Haslum, E.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hohlmann, M.; Hollis, R. S.; Holzmann, W.; Homma, K.; Hong, B.; Horaguchi, T.; Hornback, D.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Ichimiya, R.; Ikeda, Y.; Imai, K.; Inaba, M.; Iordanova, A.; Isenhower, D.; Ishihara, M.; Issah, M.; Ivanishchev, D.; Iwanaga, Y.; Jacak, B. V.; Jezghani, M.; Jia, J.; Jiang, X.; Jin, J.; Johnson, B. M.; Jones, T.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kajihara, F.; Kamin, J.; Kanda, S.; Kang, J. H.; Kapustinsky, J.; Karatsu, K.; Kasai, M.; Kawall, D.; Kawashima, M.; Kazantsev, A. V.; Kempel, T.; Key, J. A.; Khachatryan, V.; Khanzadeev, A.; Kijima, K. M.; Kikuchi, J.; Kim, A.; Kim, B. I.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, G. W.; Kim, M.; Kim, Y.-J.; Kimelman, B.; Kinney, E.; Kiss, Á.; Kistenev, E.; Kitamura, R.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kochenda, L.; Komkov, B.; Konno, M.; Koster, J.; Kotov, D.; Král, A.; Kravitz, A.; Kunde, G. J.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Leitch, M. J.; Leite, M. A. L.; Li, X.; Lichtenwalner, P.; Liebing, P.; Lim, S. H.; Linden Levy, L. A.; Liška, T.; Liu, H.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Malik, M. D.; Manion, A.; Manko, V. I.; Mannel, E.; Mao, Y.; Masui, H.; Matathias, F.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Means, N.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Miki, K.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Montuenga, P.; Moon, H. J.; Moon, T.; Morino, Y.; Morreale, A.; Morrison, D. P.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagamiya, S.; Nagashima, K.; Nagle, J. L.; Naglis, M.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nam, S.; Nattrass, C.; Netrakanti, P. K.; Newby, J.; Nguyen, M.; Nihashi, M.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Nyanin, A. S.; Oakley, C.; O'Brien, E.; Oda, S. X.; Ogilvie, C. A.; Oka, M.; Okada, K.; Onuki, Y.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ouchida, M.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Park, W. J.; Pate, S. F.; Patel, M.; Pei, H.; Peng, J.-C.; Pereira, H.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Proissl, M.; Purschke, M. L.; Qu, H.; Rak, J.; Ramson, B. J.; Ravinovich, I.; Read, K. F.; Rembeczki, S.; Reygers, K.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Rinn, T.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rosen, C. A.; Rosendahl, S. S. E.; Rowan, Z.; Rubin, J. G.; Ružička, P.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sakashita, K.; Sako, H.; Samsonov, V.; Sano, S.; Sarsour, M.; Sato, S.; Sato, T.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Silvestre, C.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Snowball, M.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takagui, E. M.; Taketani, A.; Tanabe, R.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Themann, H.; Thomas, D.; Thomas, T. L.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Togawa, M.; Toia, A.; Tomášek, L.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, R.; Towell, R. S.; Tserruya, I.; Tsuchimoto, Y.; Vale, C.; Valle, H.; van Hecke, H. W.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Wei, R.; Wessels, J.; White, A. S.; White, S. N.; Winter, D.; Woody, C. L.; Wright, R. M.; Wysocki, M.; Xia, B.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamaura, K.; Yang, R.; Yanovich, A.; Ying, J.; Yokkaichi, S.; Yoo, J. H.; Yoon, I.; You, Z.; Young, G. R.; Younus, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zhou, S.; Zou, L.; Phenix Collaboration

2016-03-01

Jet production rates are measured in p +p and d +Au collisions at √{sN N}=200 GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the R =0.3 anti-kt algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multiwire proportional chambers, and the jet transverse momentum (pT) spectra are corrected for the detector response. Spectra are reported for jets with 12

Correlations induced by depressing synapses in critically self-organized networks with quenched dynamics

NASA Astrophysics Data System (ADS)

Campos, João Guilherme Ferreira; Costa, Ariadne de Andrade; Copelli, Mauro; Kinouchi, Osame

2017-04-01

In a recent work, mean-field analysis and computer simulations were employed to analyze critical self-organization in networks of excitable cellular automata where randomly chosen synapses in the network were depressed after each spike (the so-called annealed dynamics). Calculations agree with simulations of the annealed version, showing that the nominal branching ratio σ converges to unity in the thermodynamic limit, as expected of a self-organized critical system. However, the question remains whether the same results apply to the biological case where only the synapses of firing neurons are depressed (the so-called quenched dynamics). We show that simulations of the quenched model yield significant deviations from σ =1 due to spatial correlations. However, the model is shown to be critical, as the largest eigenvalue of the synaptic matrix approaches unity in the thermodynamic limit, that is, λc=1 . We also study the finite size effects near the critical state as a function of the parameters of the synaptic dynamics.

Design and overall performance of four highly loaded, high speed inlet stages for an advanced high-pressure-ratio core compressor

NASA Technical Reports Server (NTRS)

Reid, L.; Moore, R. D.

1978-01-01

The detailed design and overall performances of four inlet stages for an advanced core compressor are presented. These four stages represent two levels of design total pressure ratio (1.82 and 2.05), two levels of rotor aspect ratio (1.19 and 1.63), and two levels of stator aspect ratio (1.26 and 1.78). The individual stages were tested over the stable operating flow range at 70, 90, and 100 percent of design speeds. The performances of the low aspect ratio configurations were substantially better than those of the high aspect ratio configurations. The two low aspect ratio configurations achieved peak efficiencies of 0.876 and 0.872 and corresponding stage efficiencies of 0.845 and 0.840. The high aspect ratio configurations achieved peak ratio efficiencies of 0.851 and 0.849 and corresponding stage efficiencies of 0.821 and 0.831.

A multidimensional approach to training mathematics students at a university: improving the efficiency through the unity of social, psychological and pedagogical aspects

NASA Astrophysics Data System (ADS)

Kuznetsova, Elena; Matytcina, Marina

2018-04-01

The article deals with social, psychological and pedagogical aspects of teaching mathematics students at universities. The sociological portrait and the factors influencing a career choice of a mathematician have been investigated through the survey results of 198 first-year students of applied mathematics major at 27 state universities (Russia). Then, psychological characteristics of mathematics students have been examined based on scientific publications. The obtained results have allowed us to reveal pedagogical conditions and specific ways of training mathematics students in the process of their education at university. The article also contains the analysis of approaches to the development of mathematics education both in Russia and in other countries. The results may be useful for teaching students whose training requires in-depth knowledge of mathematics.

Statewide analysis of the drainage-area ratio method for 34 streamflow percentile ranges in Texas

USGS Publications Warehouse

Asquith, William H.; Roussel, Meghan C.; Vrabel, Joseph

2006-01-01

The drainage-area ratio method commonly is used to estimate streamflow for sites where no streamflow data are available using data from one or more nearby streamflow-gaging stations. The method is intuitive and straightforward to implement and is in widespread use by analysts and managers of surface-water resources. The method equates the ratio of streamflow at two stream locations to the ratio of the respective drainage areas. In practice, unity often is assumed as the exponent on the drainage-area ratio, and unity also is assumed as a multiplicative bias correction. These two assumptions are evaluated in this investigation through statewide analysis of daily mean streamflow in Texas. The investigation was made by the U.S. Geological Survey in cooperation with the Texas Commission on Environmental Quality. More than 7.8 million values of daily mean streamflow for 712 U.S. Geological Survey streamflow-gaging stations in Texas were analyzed. To account for the influence of streamflow probability on the drainage-area ratio method, 34 percentile ranges were considered. The 34 ranges are the 4 quartiles (0-25, 25-50, 50-75, and 75-100 percent), the 5 intervals of the lower tail of the streamflow distribution (0-1, 1-2, 2-3, 3-4, and 4-5 percent), the 20 quintiles of the 4 quartiles (0-5, 5-10, 10-15, 15-20, 20-25, 25-30, 30-35, 35-40, 40-45, 45-50, 50-55, 55-60, 60-65, 65-70, 70-75, 75-80, 80-85, 85-90, 90-95, and 95-100 percent), and the 5 intervals of the upper tail of the streamflow distribution (95-96, 96-97, 97-98, 98-99 and 99-100 percent). For each of the 253,116 (712X711/2) unique pairings of stations and for each of the 34 percentile ranges, the concurrent daily mean streamflow values available for the two stations provided for station-pair application of the drainage-area ratio method. For each station pair, specific statistical summarization (median, mean, and standard deviation) of both the exponent and bias-correction components of the drainage-area ratio method were computed. Statewide statistics (median, mean, and standard deviation) of the station-pair specific statistics subsequently were computed and are tabulated herein. A separate analysis considered conditioning station pairs to those stations within 100 miles of each other and with the absolute value of the logarithm (base-10) of the ratio of the drainage areas greater than or equal to 0.25. Statewide statistics of the conditional station-pair specific statistics were computed and are tabulated. The conditional analysis is preferable because of the anticipation that small separation distances reflect similar hydrologic conditions and the observation of large variation in exponent estimates for similar-sized drainage areas. The conditional analysis determined that the exponent is about 0.89 for streamflow percentiles from 0 to about 50 percent, is about 0.92 for percentiles from about 50 to about 65 percent, and is about 0.93 for percentiles from about 65 to about 85 percent. The exponent decreases rapidly to about 0.70 for percentiles nearing 100 percent. The computation of the bias-correction factor is sensitive to the range analysis interval (range of streamflow percentile); however, evidence suggests that in practice the drainage-area method can be considered unbiased. Finally, for general application, suggested values of the exponent are tabulated for 54 percentiles of daily mean streamflow in Texas; when these values are used, the bias correction is unity.

Effects of Blowing Spanwise from the Tips of Low-Aspect Ratio Wings of Varying Taper Ratio, with Application to Improving STOL Capability of Fighter Aircraft.

DTIC Science & Technology

1983-02-01

aspect ratio is relatively small. Brooks (ref. 1) worked with rectangular fins of 0.62 and 1.24 aspect ratio in a water medium and showed very large ...airflow rates. Lloyd (ref. 3) worked with an aspect ratio 2.0 rectangular wing using a very wide range of jet momentum coefficient; his results were in...D-A1i35 688 EFFECTS OF BLOWING SPANWISE FROM THE TIPS OF LOW ASPECT in, RATIO WINGS OF VA .(U) NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA

Numerical studies of the reversed-field pinch at high aspect ratio

NASA Astrophysics Data System (ADS)

Sätherblom, H.-E.; Drake, J. R.

1998-10-01

The reversed field pinch (RFP) configuration at an aspect ratio of 8.8 is studied numerically by means of the three-dimensional magnetohydrodynamic code DEBS [D. D. Schnack et al., J. Comput. Phys. 70, 330 (1987)]. This aspect ratio is equal to that of the Extrap T1 experiment [S. Mazur et al., Nucl. Fusion 34, 427 (1994)]. A numerical study of a RFP with this level of aspect ratio requires extensive computer achievements and has hitherto not been performed. The results are compared with previous studies [Y. L. Ho et al., Phys. Plasmas 2, 3407 (1995)] of lower aspect ratio RFP configurations. In particular, an evaluation of the extrapolation to the aspect ratio of 8.8 made in this previous study shows that the extrapolation of the spectral spread, as well as most of the other findings, are confirmed. An important exception, however, is the magnetic diffusion coefficient, which is found to decrease with aspect ratio. Furthermore, an aspect ratio dependence of the magnetic energy and of the helicity of the RFP is found.

Unity connecting module placed in new site in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

The Unity connecting module, part of the International Space Station, is placed in a work station in the Space Station Processing Facility (SSPF). As the primary payload on mission STS-88, scheduled to launch Dec. 3, 1998, Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time. In the SSPF, Unity is undergoing testing such as the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle, as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter, and the common berthing mechanism to which other space station elements will dock. Unity is expected to be ready for installation into the Shuttle's payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27.

Analysis of Hydrogen Generation through Thermochemical Gasification of Coconut Shell Using Thermodynamic Equilibrium Model Considering Char and Tar

PubMed Central

Rupesh, Shanmughom; Muraleedharan, Chandrasekharan; Arun, Palatel

2014-01-01

This work investigates the potential of coconut shell for air-steam gasification using thermodynamic equilibrium model. A thermodynamic equilibrium model considering tar and realistic char conversion was developed using MATLAB software to predict the product gas composition. After comparing it with experimental results the prediction capability of the model is enhanced by multiplying equilibrium constants with suitable coefficients. The modified model is used to study the effect of key process parameters like temperature, steam to biomass ratio, and equivalence ratio on product gas yield, composition, and heating value of syngas along with gasification efficiency. For a steam to biomass ratio of unity, the maximum mole fraction of hydrogen in the product gas is found to be 36.14% with a lower heating value of 7.49 MJ/Nm3 at a gasification temperature of 1500 K and equivalence ratio of 0.15. PMID:27433487

Analysis of Hydrogen Generation through Thermochemical Gasification of Coconut Shell Using Thermodynamic Equilibrium Model Considering Char and Tar.

PubMed

Rupesh, Shanmughom; Muraleedharan, Chandrasekharan; Arun, Palatel

2014-01-01

This work investigates the potential of coconut shell for air-steam gasification using thermodynamic equilibrium model. A thermodynamic equilibrium model considering tar and realistic char conversion was developed using MATLAB software to predict the product gas composition. After comparing it with experimental results the prediction capability of the model is enhanced by multiplying equilibrium constants with suitable coefficients. The modified model is used to study the effect of key process parameters like temperature, steam to biomass ratio, and equivalence ratio on product gas yield, composition, and heating value of syngas along with gasification efficiency. For a steam to biomass ratio of unity, the maximum mole fraction of hydrogen in the product gas is found to be 36.14% with a lower heating value of 7.49 MJ/Nm(3) at a gasification temperature of 1500 K and equivalence ratio of 0.15.

Extension of the dielectric breakdown model for simulation of viscous fingering at finite viscosity ratios.

PubMed

Doorwar, Shashvat; Mohanty, Kishore K

2014-07-01

Immiscible displacement of viscous oil by water in a petroleum reservoir is often hydrodynamically unstable. Due to similarities between the physics of dielectric breakdown and immiscible flow in porous media, we extend the existing dielectric breakdown model to simulate viscous fingering patterns for a wide range of viscosity ratios (μ(r)). At low values of power-law index η, the system behaves like a stable Eden growth model and as the value of η is increased to unity, diffusion limited aggregation-like fractals appear. This model is compared with our two-dimensional (2D) experiments to develop a correlation between the viscosity ratio and the power index, i.e., η = 10(-5)μ(r)(0.8775). The 2D and three-dimensional (3D) simulation data appear scalable. The fingering pattern in 3D simulations at finite viscosity ratios appear qualitatively similar to the few experimental results published in the literature.

An investigation of the effect of aspect and compression ratios on sediment dispersion using discrete element modelling

NASA Astrophysics Data System (ADS)

Wang, Dong; Tan, Danielle S.

2017-12-01

We use discrete element modelling to simulate a system of sand being released underwater, similar to the process of releasing sediment tailings back into the sea in nodule harvesting, in 2D. The force model includes concentration-dependent drag, buoyancy, `added mass' and Stokeslet disturbance. For a fixed number of uniform-sized particles, we vary the aspect ratio and the compression ratio of the rectangular mass of granular media pre-release. We observed that the spreading leads to a nonlinear increase with aspect ratio. On the other hand, when the compression ratio is increased, the total spreading increases; however the spread of the bulk of the sand decreases at small aspect ratios and increases at large aspect ratios. We proposed a simple theoretical model for the horizontal spreading which depends on both the aspect and compression ratios.

1. PERSPECTIVE VIEW OF KEX PLANT, FORMER CALLAWAY MILLS UNITY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. PERSPECTIVE VIEW OF KEX PLANT, FORMER CALLAWAY MILLS UNITY COTTON MILL (A. FRANCIS WALKER, 1900-01) FROM DUNSON STREET. UNITY COTTON MILL WAS THE FIRST OF SEVERAL TEXTILE MILLS BUILT BY THE CALLAWAY MILLS GROUP IN SOUTHWEST LAGRANGE DURING THE EARLY TWENTIETH CENTURY. NOTE REMAINING PORTION OF ORIGINAL WATER TANK TOWER IN MIDDLE OF PHOTOGRAPH. - Unity Cotton Mill, 815 Leeman Street, La Grange, Troup County, GA

High Temperature Studies of La-Monazite

DTIC Science & Technology

2004-07-01

Hay, E. Boakeye, M. D. Petry, Y. Berta, K. Von Lehmden, and J. Welch, " 5 A. Meldrum , L. A. Boatner, and R. C. Ewing, "Electron-Irradiation-Induced... Meldrum , L. A. Boatner, and R. C. Ewing, "A Comparison of Radiation Alumina-based Fiber for High Temperature Composite Reinforcement," Ceram. Eng... acid . The processing included procedures that allowed the La/P ratio to be controlled to be very close to the stoichiometric value of unity (within less

Analysis of the aerodynamic interaction between two plunging plates in tandem at low Reynolds number for maximum propulsive efficiency

NASA Astrophysics Data System (ADS)

Ortega-Casanova, Joaquin; Fernandez-Feria, Ramon

2015-11-01

The thrust generated by two heaving plates in tandem is analysed for two particular sets of configurations of interest in forward flight: a plunging leading plate with the trailing plate at rest, and the two plates heaving with the same frequency and amplitude, but varying the phase difference. The thrust efficiency of the leading plate is augmented in relation to a single plate heaving with the same frequency and amplitude in most cases. In the first configuration, we characterize the range of nondimensional heaving frequencies and amplitudes of the leading plate for which the stationary trailing plate contributes positively to the global thrust. The maximum global thrust efficiency, reached for an advance ratio slightly less than unity and a reduced frequency close to 5, is about the same as the maximum efficiency for an isolated plate. But for low frequencies the tandem configuration with the trailing plate at rest is more thrust efficient than the isolated plate. In the second configuration, we find that the maximum thrust efficiency is reached for a phase lag of 180o (counterstroking), particularly for an advance ratio unity and a reduced frequency 4.4, and it is practically the same as in the other configuration and that for a single plate. Supported by the Ministerio de Economía y Competitividad of Spain Grant no. DPI2013-40479-P.

Relative activity of cerebral subcortical gray matter in varying states of attention and awareness in normal subjects and patient studies

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

Cooper, M.; Chen, C.T.; Levy, J.

1985-05-01

An important aspect of the study of brain function involves measurement of the relationships; between activities in the subcortical gray matter of the caudate and of the thalamus; and between these structures and functional cortical areas. The authors have studied these relationships in 22 subjects under different conditions of activation, sleep and sensory deprivation using a PET VI system and F-18-2DG to determine regional cerebral metabolism. Subject activating conditions were maintained throughout the period of equilibration of F-18-2DG and E.E.G.'s were monitored. Multiple tomographic slices of 1-2 million counts were obtained simultaneously with slice separation of 14mm and each planemore » parallel to the cantho-meatal line. In activated and non-activated awake conditions for normal subjects, left and right thalmus-to-caudate ratios were similar and greater than unity. This relationship was maintained in non-REM sleep, but was reversed and divergent in REM sleep and sensory deprivation; this was also evident in 3/4 narcoleptics awake and asleep in non-REM and REM and 2/3 schizophrenics and affective disorder, subjects. This approach appears to have potential for characterizating normal and disordered regional cerebral function.« less

The Unity connecting module rests inside the payload bay of Endeavour

NASA Technical Reports Server (NTRS)

1998-01-01

The Unity connecting module rests inside the payload bay of the orbiter Endeavour at Launch Pad 39A. The first U.S. element of the International Space Station (ISS), Unity is scheduled for launch Dec. 3, 1998, on Mission STS-88. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach it to the Russian-built Zarya control module which will be in orbit at that time. The mission is expected to last nearly 12 days, landing back at the Kennedy Space Center on Dec. 14.

[Not Available].

PubMed

Engelhardt, D V

1994-01-01

The philosophical interpretation of nature around 1800 exercised a deep influence on the natural sciences and medical disciplines, especially in regard to organisms, diseases and the relationship between nature and culture. Natural scientists and speculative philosophers in the Romantic era, a special phase between the 18th and 19th century, criticized the science of their time, but they in no way challenged the value and justification of an empirical approach to nature, though they rejected the absolutizing aspect of its positivistic perspective and pleaded for the unity of natural phenomena, the responsibility of man for nature, the concept of medicine as science and art.

Mortality from non-malignant respiratory disease in the fibreglass manufacturing industry

PubMed Central

Chiazze, L; Watkins, D; Fryar, C; Fayerweather, W; Kozono, J; Biggs, V

2002-01-01

Objectives: To investigate the question of whether there is an association between workplace exposures and sociodemographic factors and mortality from non-malignant respiratory disease excluding influenza and pneumonia (NMRDxIP) among workers in a fibreglass wool manufacturing facility. Methods: A case-control study with cases and controls derived from deaths recorded from the Kansas City plant in the Owens Corning mortality surveillance system. The cases are defined as decedents with NMRDxIP as the underlying cause of death. Matched, unadjusted odds ratios (ORs) were used to assess any association between NMRDxIP and cumulative exposure history and sociodemographic factors individually. Matched, adjusted ORs were obtained by conditional logistic regression to estimate the effect of any one variable while controlling for the effect of all the others. Results: Results of the unadjusted analysis, considering variables one at a time, yielded no significant associations between NMRDxIP and any of the exposure or sociodemographic variables. The smoking OR was substantially increased (OR 5.09; 95%CI 0.65 to undeterimed). Also, there were no significant variables in a conditional logistic regression analysis in which all variables were simultaneously adjusted. ORs for respirable glass fibres were below unity at all concentrations of exposure in the adjusted analysis. For respirable silica there was no consistent relation across all exposure levels. The ORs increased through the first three exposure concentrations but decreased for the highest exposure. However, ORs although not significant, are greater than unity for all respirable concentrations of silica exposure. Conclusions: The findings for Kansas City show no association between respirable glass fibres and NMRDxIP. The adjusted ORs for all exposures to respirable fibres were less than unity. On the other hand, the ORs for silica exposures were all above unity although there was no clear dose-response relation and none of the ORs were significant. Exposures for all substances considered were very low. Further, given the number of cases and controls, the statistical power to detect relatively small increases in risk, if any increase truly exited, was relatively low. The ORs for exposures to silica were all above unity although there was no clear dose-response relation and none of the ORs were significant. These raised ORs for silica suggest that continued surveillance would be prudent. PMID:12040110

Designed Synthesis of CeO2 Nanorods and Nanowires for Studying Toxicological Effects of High Aspect Ratio Nanomaterials

PubMed Central

Ji, Zhaoxia; Wang, Xiang; Zhang, Haiyuan; Lin, Sijie; Meng, Huan; Sun, Bingbing; George, Saji; Xia, Tian; Nel, André E.; Zink, Jeffrey I.

2012-01-01

While it has been shown that high aspect ratio nanomaterials like carbon nanotubes and TiO2 nanowires can induce toxicity by acting as fiber-like substances that damage the lysosome, it is not clear what the critical lengths and aspect ratios are that induce this type of toxicity. To answer this question, we synthesized a series of cerium oxide (CeO2) nanorods and nanowires with precisely controlled lengths and aspect ratios. Both phosphate and chloride ions were shown to play critical roles in obtaining these high aspect ratio nanostructures. High resolution TEM analysis shows that single crystalline CeO2 nanorods/nanowires were formed along the [211] direction by an “oriented attachment” mechanism, followed by Ostwald ripening. The successful creation of a comprehensive CeO2 nanorod/nanowire combinatorial library allows, for the first time, the systematic study of the effect of aspect ratio on lysosomal damage, cytoxicity and IL-1β production by the human myeloid cell line (THP-1). This in vitro toxicity study demonstrated that at lengths ≥200 nm and aspect ratios ≥ 22, CeO2 nanorods induced progressive cytotoxicity and pro-inflammatory effects. The relatively low “critical” length and aspect ratio were associated with small nanorod/nanowire diameters (6–10 nm), which facilitates the formation of stacking bundles due to strong van der Waals and dipole-dipole attractions. Our results suggest that both length and diameter components of aspect ratio should be considered when addressing the cytotoxic effects of long aspect ratio materials. PMID:22564147

Method and apparatus for lead-unity-lag electric power generation system

NASA Technical Reports Server (NTRS)

Ganev, Evgeni (Inventor); Warr, William (Inventor); Salam, Mohamed (Arif) (Inventor)

2013-01-01

A method employing a lead-unity-lag adjustment on a power generation system is disclosed. The method may include calculating a unity power factor point and adjusting system parameters to shift a power factor angle to substantially match an operating power angle creating a new unity power factor point. The method may then define operation parameters for a high reactance permanent magnet machine based on the adjusted power level.

Unity connecting module before being moved to new site in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility (SSPF), the Unity connecting module, part of the International Space Station, sits on a workstand before its move to a new location in the SSPF. As the primary payload on mission STS-88, scheduled to launch Dec. 3, 1998, Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time. In the SSPF, Unity is undergoing testing such as the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle, as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter, and the common berthing mechanism to which other space station elements will dock. Unity is expected to be ready for installation into the Shuttle's payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27.

Unity connecting module moving to new site in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility (SSPF) Unity is suspended in air as it is moved to a now location in the SSPF. At right, visitors watch through a viewing window, part of the visitors tour at the Center. As the primary payload on mission STS-88, scheduled to launch Dec. 3, 1998, Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time. In the SSPF, Unity is undergoing testing such as the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle, as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter, and the common berthing mechanism to which other space station elements will dock. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27.

Unity connecting module moving to new site in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility (SSPF), workers guide the suspended Unity connecting module, part of the International Space Station, as they move it to another location in the SSPF. As the primary payload on mission STS-88, scheduled to launch Dec. 3, 1998, Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time. In the SSPF, Unity is undergoing testing such as the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle, as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter, and the common berthing mechanism to which other space station elements will dock. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27.

Unity connecting module lifted from workstand before move to new site in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

Workers in the Space Station Processing Facility (SSPF) oversee the lifting of the Unity connecting module, part of the International Space Station, for its move to another location in the SSPF. As the primary payload on mission STS-88, scheduled to launch Dec. 3, 1998, Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time. In the SSPF, Unity is undergoing testing such as the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle, as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter, and the common berthing mechanism to which other space station elements will dock. Unity is expected to be ready for installation into the Shuttle's payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27.

Unity connecting module moving to new site in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility (SSPF) the Unity connecting module, part of the International Space Station, hangs suspended during its move to another location in the SSPF. As the primary payload on mission STS-88, scheduled to launch Dec. 3, 1998, Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time. In the SSPF, Unity is undergoing testing such as the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle, as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter, and the common berthing mechanism to which other space station elements will dock. Unity is expected to be ready for installation into the Shuttle's payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27.

Unity connecting module prepared for move to new site in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

Workers in the Space Station Processing Facility (SSPF) attach a frame to lift the Unity connecting module, part of the International Space Station, for its move to another location in the SSPF. As the primary payload on mission STS-88, scheduled to launch Dec. 3, 1998, Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time. In the SSPF, Unity is undergoing testing such as the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle, as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter, and the common berthing mechanism to which other space station elements will dock. Unity is expected to be ready for installation into the Shuttle's payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27.

The Unity connecting module rests inside the payload bay of Endeavour

NASA Technical Reports Server (NTRS)

1998-01-01

This fish-eye view of the Unity connecting module reveals its immense size relative to the workers (below right). Unity rests inside the open payload bay of the orbiter Endeavour on Launch Pad 39A. At the top of bay is the docking mechanism first used with launches to Mir, the Russian space station. Unity is the first U.S. element of the International Space Station (ISS) and is scheduled for launch Dec. 3, 1998, on Mission STS-88. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach it to the Russian-built Zarya control module which will be in orbit at that time. The mission is expected to last nearly 12 days, landing back at the Kennedy Space Center on Dec. 14.

Effect of multi-walled carbon nanotubes aspect ratio and temperature on the dielectric behavior of alternating alkene-carbon monoxide polyketone nanocomposites

NASA Astrophysics Data System (ADS)

Abu-Surrah, Adnan S.; Abdul Jawad, Saadi; Al-Ramahi, Esraa; Hallak, Awni B.; Khattari, Z.

2015-04-01

New alternating poly(propylene-alt-carbon monoxide/ethylene-alt-carbon monoxide) (PECO)/multiwalled carbon nanotubes (MWCNTs) composites have been prepared. Dielectric permittivity, electric modulus and ac conductivity of the isolated materials were investigated as a function of fiber aspect ratio, frequency and temperature. For aspect ratio of 30 and 200, a transition from insulator to semiconductor was observed at frequency 1×104. However, for high aspect ratio sample (660), no transition was observed and the conductivity is frequency independent in the measured frequency range of 10-106 Hz. The conductivity increases from about 1×10-4 for the sample that contain fibers of aspect ratio 30 and reaches 5×10-2 (Ω m)-1 for aspect ratio was 660. This behavior can be modeled by a circuit that consists of a contact resistance in series with a parallel combination of resistance (R) and capacitance (C). The calculated activation energy for sample filled with fibers having aspect ratio 30 is about 0.26 eV and decreases to about 0.16 eV when the aspect ratio is 660.

Asymptotic solution of the turbulent mixing layer for velocity ratio close to unity

NASA Technical Reports Server (NTRS)

Higuera, F. J.; Jimenez, J.; Linan, A.

1996-01-01

The equations describing the first two terms of an asymptotic expansion of the solution of the planar turbulent mixing layer for values of the velocity ratio close to one are obtained. The first term of this expansion is the solution of the well-known time-evolving problem and the second, which includes the effects of the increase of the turbulence scales in the stream-wise direction, obeys a linear system of equations. Numerical solutions of these equations for a two-dimensional reacting mixing layer show that the correction to the time-evolving solution may explain the asymmetry of the entrainment and the differences in product generation observed in flip experiments.

The level of deterrence provided by data from the SPITS seismometer array to possible violations of the Comprehensive Test Ban in the Novaya Zemlya region

NASA Astrophysics Data System (ADS)

Bowers, David; Marshall, Peter D.; Douglas, Alan

2001-08-01

The yield threshold at which a fully decoupled explosion can be identified has been a recurring issue in the debate on whether the Comprehensive Nuclear Test Ban (CTB) can be adequately verified. Here, we assess this yield threshold for the Novaya Zemlya (NZ) and Kola Peninsula regions by analysing seismograms from six small body wave magnitude (mb<=3.5) seismic disturbances recorded at regional distances (1050<Δ<1300km) by the seismometer array at Spitsbergen (SPITS). Multiple filter analysis of the seismograms shows clear high-frequency Pn (f>=14Hz), except from a calibration explosion on the Kola Peninsula. From four of the disturbances studied we observe clear high-frequency Sn; the explosion showed no clear high-frequency Sn and the data from the remaining disturbance was potentially contaminated by a data glitch. Frequency-domain analysis indicates that the Pn and Sn attenuation across the Barents Sea is similar to that observed across stable tectonic regions (shields). We define a spectral magnitude for the 2.5-3.5 Hz passband that is tied to teleseismic mb from NZ explosions; the six disturbances considered have 2.3<=mb<=3.5. Three-component data are available from SPITS for four of the disturbances considered (including the explosion). From the explosion the S/P ratios on the vertical (Z), radial (R) and tangential (T) components (in the 3.0-6.0Hz passband) are all less than unity. The S/P ratios for the same passband on the Z component from the remaining three disturbances are less than unity, but the ratios on the R and T components are significantly greater than unity. We argue that S/P ratios (3.0-6.0Hz passband) of less than unity on all of the Z, R and T components at SPITS may indicate a potential treaty violation in the Kola Peninsula and NZ regions. The temporal variation of seismic noise, in the 3.0-6.0Hz passband, at SPITS suggests that our three-component S/P criterion will be effective 95 per cent of the time for disturbances with mb>=2.8. We suggest that mb=4.25+b log10W, where W is the explosive yield in kilotons (kt), with b=0.75 for W>=1, and b=1.0 for W<1, is suitable for conservatively estimating the yield threshold of a potential violation of the CTB in the NZ region. From this we infer that a 35 ton fully coupled explosion in the NZ region is likely to be identified as suspicious under the CTB using the three-component S/P criterion. Simulations show that the low-frequency decoupling factor (DF) for a fully decoupled nuclear explosion in hard rock is about 40, suggesting that such an explosion with a yield of 1.6 kt in the NZ region is likely to be identified using data from SPITS. The conservatism likely to be employed by a potential violator and uncertainties in the DFs for nuclear explosions in hard rock cavities, together with data from stations other than SPITS within 2000km of the NZ region, suggest that the yield at which a potential violator of the CTB could confidently escape detection (using decoupling) in the NZ region is in reality probably less than 0.5 kt.

The aspect ratio effects on the performances of GaN-based light-emitting diodes with nanopatterned sapphire substrates

NASA Astrophysics Data System (ADS)

Kao, Chien-Chih; Su, Yan-Kuin; Lin, Chuing-Liang; Chen, Jian-Jhong

2010-07-01

The nanopatterned sapphire substrates (NPSSs) with aspect ratio that varied from 2.00 to 2.50 were fabricated by nanoimprint lithography. We could improve the epitaxial film quality and enhance the light extraction efficiency by NPSS technique. In this work, the aspect ratio effects on the performances of GaN-based light-emitting diodes (LEDs) with NPSS were investigated. The light output enhancement of GaN-based LEDs with NPSS was increased from 11% to 27% as the aspect ratio of the NPSS increases from 2.00 to 2.50. Owing to the same improvement of crystalline quality by using various aspect ratios of NPSS, these results indicated that the aspect ratio of the NPSS is strongly related to the light extraction efficiency.

Sustainability Science as a Transdisciplinary Framework for Institutional Transformation at Unity College

NASA Astrophysics Data System (ADS)

Mulkey, S. S.

2012-12-01

Interdisciplinary programming in higher education is accepted as necessary for effective instructional delivery of complex environmental problems. Difficulties in sharing resources among disciplinary units and the need for students to sequentially access information from different disciplines limit the effectiveness of this approach. In contrast, transdisciplinary programming requires that the perspectives of various disciplines be simultaneously integrated in problem-focused pedagogy. Unity College, an environmental college in Maine, has recently adopted Sustainability Science (sensu U.S. National Academy of Science) as a framework for transdisciplinary pedagogy throughout all of its degree programs. Sustainability Science is a promising alternative framework that focuses on the dynamics of coupled human-natural systems and is defined by the problems that it addresses rather than by the disciplines it employs. Students are empowered to become brokers of knowledge, while faculty perform a curatorial role to provide students with networked resources generally external to the classroom. Although the transdisciplinary framework is effective for delivery of Sustainability Science in upper division and capstone courses, we propose this approach also for elements of our general education curriculum during the first two years of our baccalaureate programs. Classroom time is liberated for experiential student engagement and recitation. Our experience suggests that transdisciplinary programming can provide students with critical thinking skills and thus enhance the postgraduate value of their baccalaureate degree. We are coordinating the development of this distinctive curriculum delivery with a marketing program that will make Unity College accessible to a wider range of clientele. Our implementation of transdisciplinary programming will occur over a four-year period and requires explicit and fundamental change in essentially all aspects of College administration and academics.

Induced Power of the Helicopter Rotor

NASA Technical Reports Server (NTRS)

Ormiston, Robert A.

2004-01-01

A simplified rotor model was used to explore fundamental behavior of lifting rotor induced power at moderate and high advance ratios. Several rotor inflow theories, including dynamic inflow theory and prescribed-wake vortex theory, together with idealized notional airfoil stall models were employed. A number of unusual results were encountered at high advance ratios including trim control reversal and multiple trim solutions. Significant increases in rotor induced power (torque) above the ideal minimum were observed for moderately high advance ratio. Very high induced power was observed near and above unity advance ratio. The results were sensitive to the stall characteristics of the airfoil models used. An equivalent wing analysis was developed to determine induced power from Prandtl lifting line theory and help interpret the rotor induced power behavior in terms of the spanwise airload distribution. The equivalent wing approach was successful in capturing the principal variations of induced power for different configurations and operating conditions. The effects blade root cutout were found to have a significant effect on rotor trim and induced power at high advance ratios.

Numerical simulations of vortex-induced vibrations of a flexible riser with different aspect ratiosin uniform and shear currents

NASA Astrophysics Data System (ADS)

Duanmu, Yu; Zou, Lu; Wan, De-cheng

2017-12-01

This paper aimed at describing numerical simulations of vortex-induced vibrations (VIVs) of a long flexible riser with different length-to-diameter ratio (aspect ratio) in uniform and shear currents. Three aspect ratios were simulated: L/D = 500, 750 and 1 000. The simulation was carried out by the in-house computational fluid dynamics (CFD) solver viv-FOAM-SJTU developed by the authors, which was coupled with the strip method and developed on the OpenFOAM platform. Moreover, the radial basis function (RBF) dynamic grid technique is applied to the viv-FOAM-SJTU solver to simulate the VIV in both in-line (IL) and cross-flow (CF) directions of flexible riser with high aspect ratio. The validation of the benchmark case has been completed. With the same parameters, the aspect ratio shows a significant influence on VIV of a long flexible riser. The increase of aspect ratio exerted a strong effect on the IL equilibrium position of the riser while producing little effect on the curvature of riser. With the aspect ratio rose from 500 to 1 000, the maximum IL mean displacement increased from 3 times the diameter to 8 times the diameter. On the other hand, the vibration mode of the riser would increase with the increase of aspect ratio. When the aspect ratio was 500, the CF vibration was shown as a standing wave with a 3rd order single mode. When the aspect ratio was 1 000, the modal weights of the 5th and 6th modes are high, serving as the dominant modes. The effect of the flow profile on the oscillating mode becomes more and more apparent when the aspect ratio is high, and the dominant mode of riser in shear flow is usually higher than that in uniform flow. When the aspect ratio was 750, the CF oscillations in both uniform flow and shear flow showed multi-mode vibration of the 4th and 5th mode. While, the dominant mode in uniform flow is the 4th order, and the dominant mode in shear flow is the 5th order.

3. OBLIQUE PERSPECTIVE OF EASTERN FACADE OF UNITY PLANT SHOWING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. OBLIQUE PERSPECTIVE OF EASTERN FACADE OF UNITY PLANT SHOWING LANDSCAPING AND HILL. NOTE THE CORBELED BRICK SUPPORT FOR THE FIRE WALL BETWEEN SECTIONS OF THE MILL. - Unity Spinning Mill, 1402 Austin Street, La Grange, Troup County, GA

Aerodynamic Characteristics of Low-Aspect-Ratio Wings in Close Proximity to the Ground

NASA Technical Reports Server (NTRS)

Fink, Marvin P.; Lastinger, James L.

1961-01-01

A wind-tunnel investigation has been conducted to determine the effect of ground proximity on the aerodynamic characteristics of thick highly cambered rectangular wings with aspect ratios of 1. 2, 4, and 6. The results showed that, for these aspect ratios, as the ground war, approached all wings experienced increases in lift-curve slope and reductions in induced drag which resulted in increases in lift-drag ratio. Although an increase in lift-curve slope was obtained for all aspect ratios as the ground was approached, the lift coefficient at an angle of attack of 0 deg for any given aspect ratio remained nearly constant. The experimental results were in general agreement with Wieselsberger's ground-effect theory (NACA Technical Memorandum 77). As the wings approached the ground, there was an increase in static longitudinal stability at positive angles of attack. When operating in ground effect, all the wings had stability of height at positive angles of attack and instability of height at negative angles of attack. Wing-tip fairings on the wings with aspect ratios of 1 and 2 produced small increases in lift-drag ratio in ground effect. End plates extending only below the chord plane on the wing with an aspect ratio of 1 provided increases in lift coefficient and in lift-drag ratio in ground effect.

Genesee River Basin Study; Reconnaissance Report. Volume 1. Main Report.

DTIC Science & Technology

1986-01-01

River in the Towns of Chili and Riga, Monroe County, New York" was prepared in September 1969. The report gives a history of flooding and outlines...a benefit - cost ratio of less than unity. 9 A report entitled "Flood Recovery Planning Program - Preliminary Evaluation of Stony Brook and Mill Creek...Creek, Town ot (a Chili , and Ogden, Monroe County, New York," was prepared in August 1915. Ttl- report presents a brief history of flooding and

Absolute Negative Resistance Induced by Directional Electron-Electron Scattering in a Two-Dimensional Electron Gas

NASA Astrophysics Data System (ADS)

Kaya, Ismet I.; Eberl, Karl

2007-05-01

A three-terminal device formed by two electrostatic barriers crossing an asymmetrically patterned two-dimensional electron gas displays an unusual potential depression at the middle contact, yielding absolute negative resistance. The device displays momentum and current transfer ratios that far exceed unity. The observed reversal of the current or potential in the middle terminal can be interpreted as the analog of Bernoulli’s effect in a Fermi liquid. The results are explained by directional scattering of electrons in two dimensions.

International Symposium on Gas Kinetics (9th) Held in Bordeaux, France on 20-25 July 1986. Abstracts

DTIC Science & Technology

1986-07-25

J. Chem. Kinet., 14, 933 (1982). Present address: British Gas, London Research Station, Puliham, London, E’ngland. 1 -54 Synthesis and Pyrolysis of...while the cis/trans ratio of 1 - chloropropane is much higher than unity. We were interested In the alternative radical chain process which is strongly...H2 (V = 1 ) reaction and its isotopic analogs. VB. Rozenshtein, Y.M. Gershenzon,A.V. Ivanov, S.D. Ilin, S.I. Kucheryavii and S.Y. Umanskii 10.20

Processing Science of Advanced Ceramics. Materials Research Society Symposium Proceedings. Volume 155

DTIC Science & Technology

1990-09-01

can see that as the particle diameter ratio decreased more from unity, the freezing curve in the D - x phase diagram begins to show a maximum with...predicted for the rod area fraction of 0.26. Free energy curves for the two phases are shown as a function of rod concentration. The random phise has lower...fabrication techniques leing used range from consolidation of subinicron-sized powders to vapor phase deposition. ’hc papers included in this

DUST CAPTURE AND LONG-LIVED DENSITY ENHANCEMENTS TRIGGERED BY VORTICES IN 2D PROTOPLANETARY DISKS

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

Surville, Clément; Mayer, Lucio; Lin, Douglas N. C., E-mail: clement.surville@physik.uzh.ch

We study dust capture by vortices and its long-term consequences in global two-fluid inviscid disk simulations using a new polar grid code RoSSBi. We perform the longest integrations so far, several hundred disk orbits, at the highest resolution attainable in global disk simulations with dust, namely, 2048 × 4096 grid points. We vary a wide range of dust parameters, most notably the initial dust-to-gas ratio ϵ varies in the range of 10{sup −4}–10{sup −2}. Irrespective of the value of ϵ , we find rapid concentration of the dust inside vortices, reaching dust-to-gas ratios of the order of unity inside themore » vortex. We present an analytical model that describes this dust capture process very well, finding consistent results for all dust parameters. A vortex streaming instability develops, which invariably causes vortex destruction. After vortex dissipation large-scale dust rings encompassing a disk annulus form in most cases, which sustain very high dust concentration, approaching ratios of the order of unity; they persist as long as the duration of the simulations. They are sustained by a streaming instability, which manifests itself in high-density dust clumps at various scales. When vortices are particularly long-lived, rings do not form but dust clumps inside vortices can survive a long time and would likely undergo collapse by gravitational instability. Rings encompass almost an Earth mass of solid material, while even larger masses of dust do accumulate inside vortices in the earlier stage. We argue that rapid planetesimal formation would occur in the dust clumps inside the vortices as well as in the post-vortex rings.« less

Dual Active Bridge based DC Transformer LabVIEW FPGA Control Code

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

In the area of power electronics control, Field Programmable Gate Arrays (FPGAs) have the capability to outperform their Digital Signal Processor (DSP) counterparts due to the FPGA’s ability to implement true parallel processing and therefore facilitate higher switching frequencies, higher control bandwidth, and/or enhanced functionality. National Instruments (NI) has developed two platforms, Compact RIO (cRIO) and Single Board RIO (sbRIO), which combine a real-time processor with an FPGA. The FPGA can be programmed with a subset of the well-known LabVIEW graphical programming language. The candidate software implements complete control algorithms in LabVIEW FPGA for a DC Transformer (DCX) based onmore » a dual active bridge (DAB). A DCX is an isolated bi-directional DC-DC converter designed to operate at unity conversion ratio, M, defined by where Vin is the primary-side DC bus voltage, Vout is the secondary-side DC bus voltage, and n is the turns ratio of the embedded high frequency transformer (HFX). The DCX based on a DAB incorporates two H-bridges, a resonant inductor, and an HFX to provide this functionality. The candidate software employs phase-shift modulation of the two H-bridges and a feedback loop to regulate the conversion ratio at unity. The software also includes alarm-handling capabilities as well as debugging and tuning tools. The software fits on the Xilinx Virtex V LX110 FPGA embedded in the NI cRIO-9118 FPGA chassis, and with a 40 MHz base clock, supports a modulation update rate of 40 MHz, and user-settable switching frequencies and synchronized control loop update rates of tens of kHz.« less

Dust Capture and Long-lived Density Enhancements Triggered by Vortices in 2D Protoplanetary Disks

NASA Astrophysics Data System (ADS)

Surville, Clément; Mayer, Lucio; Lin, Douglas N. C.

2016-11-01

We study dust capture by vortices and its long-term consequences in global two-fluid inviscid disk simulations using a new polar grid code RoSSBi. We perform the longest integrations so far, several hundred disk orbits, at the highest resolution attainable in global disk simulations with dust, namely, 2048 × 4096 grid points. We vary a wide range of dust parameters, most notably the initial dust-to-gas ratio ɛ varies in the range of 10-4-10-2. Irrespective of the value of ɛ, we find rapid concentration of the dust inside vortices, reaching dust-to-gas ratios of the order of unity inside the vortex. We present an analytical model that describes this dust capture process very well, finding consistent results for all dust parameters. A vortex streaming instability develops, which invariably causes vortex destruction. After vortex dissipation large-scale dust rings encompassing a disk annulus form in most cases, which sustain very high dust concentration, approaching ratios of the order of unity they persist as long as the duration of the simulations. They are sustained by a streaming instability, which manifests itself in high-density dust clumps at various scales. When vortices are particularly long-lived, rings do not form but dust clumps inside vortices can survive a long time and would likely undergo collapse by gravitational instability. Rings encompass almost an Earth mass of solid material, while even larger masses of dust do accumulate inside vortices in the earlier stage. We argue that rapid planetesimal formation would occur in the dust clumps inside the vortices as well as in the post-vortex rings.

Large eddy simulation on Rayleigh–Bénard convection of cold water in the neighborhood of the maximum density

NASA Astrophysics Data System (ADS)

Huang, Xiao-Jie; Zhang, Li; Hu, Yu-Peng; Li, You-Rong

2018-06-01

In order to understand the effect of the Rayleigh number, the density inversion phenomenon and the aspect ratio on the flow patterns and the heat transfer characteristics of Rayleigh–Bénard convection of cold water in the neighborhood of the maximum density, a series of large eddy simulations are conducted by using the finite volume method. The Rayleigh number ranges between 106 and 109, the density inversion parameter and the aspect ratio are varied from 0 to 0.9 and from 0.4 to 2.5, respectively. The results indicate that the reversal of the large scale circulation (LSC) occurs with the increase of the Rayleigh number. When there exists a density inversion phenomenon, the key driver for the LSC is hot plumes. When the density inversion parameter is large enough, a stagnant region is found near the top of the container as the hot plumes cannot move to the top wall. The flow pattern structures depend mainly on the aspect ratio. When the aspect ratio is small, the rolls are vertically stacked and the flow keeps on switching among different flow states. For a moderate aspect ratio, different long-lived roll states coexist at a fixed aspect ratio. For a larger aspect ratio, the flow state is everlasting. The number of rolls increases with the increase of the aspect ratio. Furthermore, the aspect ratio has only slight influence on the time averaged Nusselt number for all density inversion parameters.

The effect of aspect ratio on adhesion and stiffness for soft elastic fibres

PubMed Central

Aksak, Burak; Hui, Chung-Yuen; Sitti, Metin

2011-01-01

The effect of aspect ratio on the pull-off stress and stiffness of soft elastic fibres is studied using elasticity and numerical analysis. The adhesive interface between a soft fibre and a smooth rigid surface is modelled using the Dugdale–Barenblatt model. Numerical simulations show that, while pull-off stress increases with decreasing aspect ratio, fibres get stiffer. Also, for sufficiently low aspect ratio fibres, failure occurs via the growth of internal cracks and pull-off stress approaches the intrinsic adhesive strength. Experiments carried out with various aspect ratio polyurethane elastomer fibres are consistent with the numerical simulations. PMID:21227962

Non-Inductively Driven Tokamak Plasmas at Near-Unity Toroidal Beta in the Pegasus Toroidal Experiment

NASA Astrophysics Data System (ADS)

Reusch, Joshua

2017-10-01

A major goal of the spherical tokamak research program is accessing a state of low internal inductance li, high elongation κ, high toroidal and normalized beta (βt and βN) , and low collisionality without solenoidal current drive. A new local helicity injection (LHI) system in the lower divertor region of the ultra-low aspect ratio Pegasus ST provides non-solenoidally driven plasmas that exhibit most of these characteristics. LHI utilizes compact, edge-localized current sources (Ainj 4 cm2, Iinj 8 kA, Vinj 1.5 kV) for plasma startup and sustainment, and can sustain more than 200 kA of plasma current. Plasma growth via LHI is enhanced by a transition from a regime of high kink-like MHD activity to one of reduced MHD activity at higher frequencies and presumably shorter wavelengths. The strong edge current drive provided by LHI results in a hollow current density profile with low li. The low aspect ratio (R0 / a 1.2) of Pegasus allows ready access to high κ and MHD stable operation at very high normalized plasma currents (IN =Ip /aBT> 15). Thomson scattering measurements indicate Te 100 eV and ne 1 ×19 m-3. The impurity Ti evolution is correlated in time with high frequency magnetic fluctuations, implying substantial reconnection ion heating is driven by the applied helicity injection. Doppler spectroscopy indicates Ti >=Te and that the anomalous ion heating scales consistently with two fluid reconnection theory. Taken together, these features provide access to very high βt plasmas. Equilibrium analyses indicate βt up to 100% and βN 6.5 is achieved. At increasingly low BT, the discharge disrupts at the no-wall ideal stability limit. In these high βt discharges, a minimum |B| well forms over 50% of the plasma volume. This unique magnetic configuration may be of interest for testing predictions of stabilizing drift wave turbulence and/or improving energetic particle confinement. This work supported by US DOE Grants DE-FG02-96ER54375 and DE-SC0006928.

Standard atomic volumes in double-stranded DNA and packing in protein–DNA interfaces

PubMed Central

Nadassy, Katalin; Tomás-Oliveira, Isabel; Alberts, Ian; Janin, Joël; Wodak, Shoshana J.

2001-01-01

Standard volumes for atoms in double-stranded B-DNA are derived using high resolution crystal structures from the Nucleic Acid Database (NDB) and compared with corresponding values derived from crystal structures of small organic compounds in the Cambridge Structural Database (CSD). Two different methods are used to compute these volumes: the classical Voronoi method, which does not depend on the size of atoms, and the related Radical Planes method which does. Results show that atomic groups buried in the interior of double-stranded DNA are, on average, more tightly packed than in related small molecules in the CSD. The packing efficiency of DNA atoms at the interfaces of 25 high resolution protein–DNA complexes is determined by computing the ratios between the volumes of interfacial DNA atoms and the corresponding standard volumes. These ratios are found to be close to unity, indicating that the DNA atoms at protein–DNA interfaces are as closely packed as in crystals of B-DNA. Analogous volume ratios, computed for buried protein atoms, are also near unity, confirming our earlier conclusions that the packing efficiency of these atoms is similar to that in the protein interior. In addition, we examine the number, volume and solvent occupation of cavities located at the protein–DNA interfaces and compared them with those in the protein interior. Cavities are found to be ubiquitous in the interfaces as well as inside the protein moieties. The frequency of solvent occupation of cavities is however higher in the interfaces, indicating that those are more hydrated than protein interiors. Lastly, we compare our results with those obtained using two different measures of shape complementarity of the analysed interfaces, and find that the correlation between our volume ratios and these measures, as well as between the measures themselves, is weak. Our results indicate that a tightly packed environment made up of DNA, protein and solvent atoms plays a significant role in protein–DNA recognition. PMID:11504874

Study by the Prandtl-Glauert method of compressibility effects and critical Mach number for ellipsoids of various aspect ratios and thickness ratios

NASA Technical Reports Server (NTRS)

Hess, Robert V; Gardner, Clifford S

1947-01-01

By using the Prandtl-Glauert method that is valid for three-dimensional flow problems, the value of the maximum incremental velocity for compressible flow about thin ellipsoids at zero angle of attack is calculated as a function of the Mach number for various aspect ratios and thickness ratios. The critical Mach numbers of the various ellipsoids are also determined. The results indicate an increase in critical Mach number with decrease in aspect ratio which is large enough to explain experimental results on low-aspect-ratio wings at zero lift.

Flow and Pollutant Transport in Urban Street Canyons of Different Aspect Ratios with Ground Heating: Large-Eddy Simulation

NASA Astrophysics Data System (ADS)

Li, Xian-Xiang; Britter, Rex E.; Norford, Leslie K.; Koh, Tieh-Yong; Entekhabi, Dara

2012-02-01

A validated large-eddy simulation model was employed to study the effect of the aspect ratio and ground heating on the flow and pollutant dispersion in urban street canyons. Three ground-heating intensities (neutral, weak and strong) were imposed in street canyons of aspect ratio 1, 2, and 0.5. The detailed patterns of flow, turbulence, temperature and pollutant transport were analyzed and compared. Significant changes of flow and scalar patterns were caused by ground heating in the street canyon of aspect ratio 2 and 0.5, while only the street canyon of aspect ratio 0.5 showed a change in flow regime (from wake interference flow to skimming flow). The street canyon of aspect ratio 1 does not show any significant change in the flow field. Ground heating generated strong mixing of heat and pollutant; the normalized temperature inside street canyons was approximately spatially uniform and somewhat insensitive to the aspect ratio and heating intensity. This study helps elucidate the combined effects of urban geometry and thermal stratification on the urban canyon flow and pollutant dispersion.

Unity hatch closed in preparation for launch on STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

Workers in the Space Station Processing Facility prepare the Unity connecting module for closure before its launch aboard Space Shuttle Endeavour on STS-88 in December. Unity will now undergo a series of leak checks before a final purge of clean, dry air inside the module to ready it for initial operations in space. Other testing includes the common berthing mechanism to which other space station elements will dock and the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter. The next time the hatch will be opened it will be by astronauts on orbit. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27. The Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time.

Unity hatch closed in preparation for launch on STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

Workers in the Space Station Processing Facility prepare the hatch of the Unity connecting module for closure before its launch aboard Space Shuttle Endeavour on STS-88 in December. Unity will now undergo a series of leak checks before a final purge of clean, dry air inside the module to ready it for initial operations in space. Other testing includes the common berthing mechanism to which other space station elements will dock and the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter. The next time the hatch will be opened it will be by astronauts on orbit. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27. The Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time.

Unity connecting module lowered to new site in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility (SSPF), the Unity connecting module, part of the International Space Station, is lowered to its new location in the SSPF. In the background, visitors watch through a viewing window, part of the visitors tour at the Center. As the primary payload on mission STS-88, scheduled to launch Dec. 3, 1998, Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time. In the SSPF, Unity is undergoing testing such as the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle, as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter, and the common berthing mechanism to which other space station elements will dock. Unity is expected to be ready for installation into the Shuttle's payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27.

Effect of Aspect Ratio on the Low-Speed Lateral Control Characteristics of Untapered Low-Aspect-Ratio Wings Equipped with Flap and with Retractable Ailerons

NASA Technical Reports Server (NTRS)

Fischel, Jack; Naeseth, Rodger L; Hagerman, John R; O'Hare, William M

1952-01-01

A low-speed wind-tunnel investigation was made to determine the lateral control characteristics of a series of untapered low-aspect-ratio wings. Sealed flap ailerons of various spans and spanwise locations were investigated on unswept wings of aspect ratios 1.13, 1.13, 4.13, and 6.13; and various projections of 0.60-semispan retractable ailerons were investigated on the unsweptback wings of aspect ratios 1.13, 2.13, and 4.13 and on a 45 degree sweptback wing. The retractable ailerons investigated on the unswept wings spanned the outboard stations of each wing; whereas the plain and stepped retractable ailerons investigated on the sweptback wing were located at various spanwise stations. Design charts based on experimental results are presented for estimating the flap aileron effectiveness for low-aspect-ratio, untapered, unswept.

Achieving high aspect ratio wrinkles by modifying material network stress.

PubMed

Chen, Yu-Cheng; Wang, Yan; McCarthy, Thomas J; Crosby, Alfred J

2017-06-07

Wrinkle aspect ratio, or the amplitude divided by the wavelength, is hindered by strain localization transitions when an increasing global compressive stress is applied to synthetic material systems. However, many examples from living organisms show extremely high aspect ratios, such as gut villi and flower petals. We use three experimental approaches to demonstrate that these high aspect ratio structures can be achieved by modifying the network stress in the wrinkle substrate. We modify the wrinkle stress and effectively delay the strain localization transition, such as folding, to larger aspect ratios by using a zero-stress initial wavy substrate, creating a secondary network with post-curing, or using chemical stress relaxation materials. A wrinkle aspect ratio as high as 0.85, almost three times higher than common values of synthetic wrinkles, is achieved, and a quantitative framework is presented to provide understanding the different strategies and predictions for future investigations.

Unity Within Diversity.

ERIC Educational Resources Information Center

Kong, Shiu L., Ed.; Ray, Riten, Ed.

This monograph contains the speeches and resolutions of representatives of forty-one ethnocultural groups residing in Canada. Included are: (1) opening messages by Pierre Trudeau, Joe Clark, Edward Broadbent, and Alex Chumak; (2) a discussion by Norman Cafik on federalism, multicultural groups, and Canadian unity; (3) remarks on Canadian unity by…

Global Model of Time-Modulated Electronegative Discharges for Neutral Radical and Electron Temperature Control

NASA Astrophysics Data System (ADS)

Kim, Sungjin; Lieberman, M. A.; Lichtenberg, A. J.

2003-10-01

Control and reduction of neutral radical flux/ion flux ratio and electron temperature Te is required for next generation etching in the microelectronics industry. We investigate time-modulated power for these purposes using a volume-averaged (global) oxygen discharge model, We consider pressures of 10-50 mTorr and plasma densities of 10^10-10^11 cm-3. In this regime, the discharge is found to be weakly electronegative. The modulation period and the duty ratio (on-time/period) are varied to determine the optimum conditions for reduction of FR= O-atom flux/ion flux and T_e. Two chambers with different height/diameter ratios (<< 1, and unity) are examined to determine the influence of the surface-area/volume ratio. At a fixed duty ratio, both FR and Te are found to have minimum values as the pulse period is varied, with the minimum value decreasing as the duty ratio decreases. Significant reductions in FR and Te are found. Support provided by Lam Research, NSF Grant ECS-0139956, California industries, and UC-SMART Contract SM99-10051.

Centrality-Dependent Modification of Jet-Production Rates in Deuteron-Gold Collisions at √[s(NN)]=200 GeV.

PubMed

Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Bataineh, H; Alexander, J; Alfred, M; Angerami, A; Aoki, K; Apadula, N; Aramaki, Y; Asano, H; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Bandara, N S; Bannier, B; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Bazilevsky, A; Beaumier, M; Beckman, S; Belikov, S; Belmont, R; Bennett, R; Berdnikov, A; Berdnikov, Y; Bhom, J H; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Campbell, S; Caringi, A; Chen, C-H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; Conesa Del Valle, Z; Connors, M; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Danley, T W; Das, K; Datta, A; Daugherity, M S; David, G; Dayananda, M K; DeBlasio, K; Dehmelt, K; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Diss, P B; Do, J H; Donadelli, M; D'Orazio, L; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Dutta, D; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Fadem, B; Feege, N; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gal, C; Gallus, P; Garg, P; Garishvili, I; Ge, H; Giordano, F; Glenn, A; Gong, H; Gonin, M; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grim, G; Grosse Perdekamp, M; Gunji, T; Gustafsson, H-Å; Hachiya, T; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Hamilton, H F; Han, R; Han, S Y; Hanks, J; Hasegawa, S; Haseler, T O S; Hashimoto, K; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Hoshino, T; Hotvedt, N; Huang, J; Huang, S; Ichihara, T; Ichimiya, R; Ikeda, Y; Imai, K; Inaba, M; Iordanova, A; Isenhower, D; Ishihara, M; Issah, M; Ivanishchev, D; Iwanaga, Y; Jacak, B V; Jezghani, M; Jia, J; Jiang, X; Jin, J; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kamin, J; Kanda, S; Kang, J H; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Key, J A; Khachatryan, V; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, C; Kim, D J; Kim, E-J; Kim, G W; Kim, M; Kim, Y-J; Kimelman, B; Kinney, E; Kiss, Á; Kistenev, E; Kitamura, R; Klatsky, J; Kleinjan, D; Kline, P; Koblesky, T; Kochenda, L; Komkov, B; Konno, M; Koster, J; Kotov, D; Král, A; Kravitz, A; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, S; Lee, S H; Leitch, M J; Leite, M A L; Li, X; Lichtenwalner, P; Liebing, P; Lim, S H; Linden Levy, L A; Liška, T; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Meles, A; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Miki, K; Milov, A; Mishra, D K; Mitchell, J T; Miyasaka, S; Mizuno, S; Mohanty, A K; Montuenga, P; Moon, H J; Moon, T; Morino, Y; Morreale, A; Morrison, D P; Moukhanova, T V; Murakami, T; Murata, J; Mwai, A; Nagamiya, S; Nagashima, K; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakagomi, H; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Nattrass, C; Netrakanti, P K; Newby, J; Nguyen, M; Nihashi, M; Niida, T; Nishimura, S; Nouicer, R; Novák, T; Novitzky, N; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Orjuela Koop, J D; Osborn, J D; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, I H; Park, J S; Park, S; Park, S K; Park, W J; Pate, S F; Patel, M; Pei, H; Peng, J-C; Pereira, H; Perepelitsa, D V; Perera, G D N; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pinson, R; Pisani, R P; Proissl, M; Purschke, M L; Qu, H; Rak, J; Ramson, B J; Ravinovich, I; Read, K F; Rembeczki, S; Reygers, K; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Rinn, T; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Rowan, Z; Rubin, J G; Ružička, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; Sako, H; Samsonov, V; Sano, S; Sarsour, M; Sato, S; Sato, T; Sawada, S; Schaefer, B; Schmoll, B K; Sedgwick, K; Seele, J; Seidl, R; Sen, A; Seto, R; Sett, P; Sexton, A; Sharma, D; Shein, I; Shibata, T-A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slunečka, M; Snowball, M; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Stenlund, E; Stepanov, M; Stoll, S P; Sugitate, T; Sukhanov, A; Sumita, T; Sun, J; Sziklai, J; Takagui, E M; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Themann, H; Thomas, D; Thomas, T L; Tieulent, R; Timilsina, A; Todoroki, T; Togawa, M; Toia, A; Tomášek, L; Tomášek, M; Torii, H; Towell, C L; Towell, R; Towell, R S; Tserruya, I; Tsuchimoto, Y; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; White, A S; White, S N; Winter, D; Woody, C L; Wright, R M; Wysocki, M; Xia, B; Xue, L; Yalcin, S; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Ying, J; Yokkaichi, S; Yoo, J H; Yoon, I; You, Z; Young, G R; Younus, I; Yu, H; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S; Zou, L

2016-03-25

Jet production rates are measured in p+p and d+Au collisions at sqrt[s_{NN}]=200  GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the R=0.3 anti-k_{t} algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multiwire proportional chambers, and the jet transverse momentum (p_{T}) spectra are corrected for the detector response. Spectra are reported for jets with 12

Centrality-Dependent Modification of Jet-Production Rates in Deuteron-Gold Collisions at s N N = 200 GeV

DOE PAGES

Adare, A.

2016-03-24

Wemore » measured jet production rates in p+p and d+Au collisions at s N N = 200 GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the R=0.3 anti-k t algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multiwire proportional chambers, and the jet transverse momentum (p T) spectra are corrected for the detector response. Spectra are reported for jets with 12T<50 GeV/c, within a pseudorapidity acceptance of |η|<0.3. The nuclear-modification factor (R dAu) values for 0%–100% d+Au events are found to be consistent with unity, constraining the role of initial state effects on jet production. Nonetheless, the centrality-selected R dAu values and central-to-peripheral ratios (R CP) show large, p T-dependent deviations from unity, challenging the conventional models that relate hard-process rates and soft-particle production in collisions involving nuclei.« less

Recoil ions from the β decay of 134Sb confined in a Paul trap

NASA Astrophysics Data System (ADS)

Siegl, K.; Scielzo, N. D.; Czeszumska, A.; Clark, J. A.; Savard, G.; Aprahamian, A.; Caldwell, S. A.; Alan, B. S.; Burkey, M. T.; Chiara, C. J.; Greene, J. P.; Harker, J.; Marley, S. T.; Morgan, G. E.; Munson, J. M.; Norman, E. B.; Orford, R.; Padgett, S.; Galván, A. Perez; Sharma, K. S.; Strauss, S. Y.

2018-03-01

The low-energy recoiling ions from the β decay of 134Sb were studied by using the Beta-decay Paul Trap. Using this apparatus, singly charged ions were suspended in vacuum at the center of a detector array used to detect emitted β particles, γ rays, and recoil ions in coincidence. The recoil ions emerge from the trap with negligible scattering, allowing β -decay properties and the charge-state distribution of the daughter ions to be determined from the β -ion coincidences. First-forbidden β -decay theory predicts a β -ν correlation coefficient of nearly unity for the 0- to 0+ transition from the ground state of 134Sb to the ground state of 134Te. Although this transition was expected to have a nearly 100% branching ratio, an additional 17.2(52)% of the β -decay strength must populate high-lying excited states to obtain an angular correlation consistent with unity. The extracted charge-state distribution of the recoiling ions was compared with existing β -decay results and the average charge state was found to be consistent with the results from lighter nuclei.

Political Geography and Canada's National Unity Problem.

ERIC Educational Resources Information Center

Barlow, I.M.

1980-01-01

This article is intended to add to the debate on political geography by considering its relevance and application and by outlining ways in which it can contribute to an understanding of Canada's national unity problem. Information is presented on Canada and national unity, state viability, internal organization of the state, politics, electoral…

Global War on Terrorism: Executing War without Unity of Command

DTIC Science & Technology

2007-03-09

41 outlined 14 principles of management , which apply to this discussion. He states, “authority and responsibility, unity of command, unity of...Fayol, “General Principles of Management ,” in Classics of Organization Theory, ed. Jay M. Shafritz, J. Steven Ott, and Yong Suk Jang (Belmont,CA

The Node 1 (or Unity) Module for the International Space Station

NASA Technical Reports Server (NTRS)

1997-01-01

This photograph, taken by the Boeing Company, shows Node 1 (also called Unity), the first U.S. Module for the International Space Station (ISS), with its hatch door installed. The Node 1, or Unity, serves as a cornecting passageway to Space Station modules and was manufactured by the Boeing Company at the Marshall Space Flight Center from 1994 to 1997. The U.S. built Unity module was launched aboard the orbiter Endeavour (STS-88 mission) on December 4, 1998 and connected to the Zarya, the Russian-built Functional Energy Block (FGB). The Zarya was launched on a Russian proton rocket prior to the launch of the Unity. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation.

The Unity connecting module rests inside the payload bay of Endeavour

NASA Technical Reports Server (NTRS)

1998-01-01

The Unity connecting module rests inside the open payload bay of the orbiter Endeavour at Launch Pad 39A. At the top of bay is the docking mechanism first used with launches to Mir, the Russian space station. Unity is the first U.S. element of the International Space Station (ISS) and is scheduled for launch Dec. 3, 1998, on Mission STS-88. The Unity is a connecting passageway to the living and working areas of ISS. While on orbit, the flight crew will deploy Unity from the payload bay and attach it to the Russian-built Zarya control module which will be in orbit at that time. The mission is expected to last nearly 12 days, landing back at the Kennedy Space Center on Dec. 14.

Enhanced charge efficiency and reduced energy use in capacitive deionization by increasing the discharge voltage.

PubMed

Kim, T; Dykstra, J E; Porada, S; van der Wal, A; Yoon, J; Biesheuvel, P M

2015-05-15

Capacitive deionization (CDI) is an electrochemical method for water desalination using porous carbon electrodes. A key parameter in CDI is the charge efficiency, Λ, which is the ratio of salt adsorption over charge in a CDI-cycle. Values for Λ in CDI are typically around 0.5-0.8, significantly less than the theoretical maximum of unity, due to the fact that not only counterions are adsorbed into the pores of the carbon electrodes, but at the same time coions are released. To enhance Λ, ion-exchange membranes (IEMs) can be implemented. With membranes, Λ can be close to unity because the membranes only allow passage for the counterions. Enhancing the value of Λ is advantageous as this implies a lower electrical current and (at a fixed charging voltage) a reduced energy use. We demonstrate how, without the need to include IEMs, the charge efficiency can be increased to values close to the theoretical maximum of unity, by increasing the cell voltage during discharge, with only a small loss of salt adsorption capacity per cycle. In separate constant-current CDI experiments, where after some time the effluent salt concentration reaches a stable value, this value is reached earlier with increased discharge voltage. We compare the experimental results with predictions of porous electrode theory which includes an equilibrium Donnan electrical double layer model for salt adsorption in carbon micropores. Our results highlight the potential of modified operational schemes in CDI to increase charge efficiency and reduce energy use of water desalination. Copyright © 2014 Elsevier Inc. All rights reserved.

Isoprene photochemistry over the Amazon rainforest.

PubMed

Liu, Yingjun; Brito, Joel; Dorris, Matthew R; Rivera-Rios, Jean C; Seco, Roger; Bates, Kelvin H; Artaxo, Paulo; Duvoisin, Sergio; Keutsch, Frank N; Kim, Saewung; Goldstein, Allen H; Guenther, Alex B; Manzi, Antonio O; Souza, Rodrigo A F; Springston, Stephen R; Watson, Thomas B; McKinney, Karena A; Martin, Scot T

2016-05-31

Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK + MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4-0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). This abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest.

Isoprene photochemistry over the Amazon rainforest

NASA Astrophysics Data System (ADS)

Liu, Yingjun; Brito, Joel; Dorris, Matthew R.; Rivera-Rios, Jean C.; Seco, Roger; Bates, Kelvin H.; Artaxo, Paulo; Duvoisin, Sergio; Keutsch, Frank N.; Kim, Saewung; Goldstein, Allen H.; Guenther, Alex B.; Manzi, Antonio O.; Souza, Rodrigo A. F.; Springston, Stephen R.; Watson, Thomas B.; McKinney, Karena A.; Martin, Scot T.

2016-05-01

Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK + MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4-0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). This abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest.

New data on selected Ivory Coast tektites

USGS Publications Warehouse

Cuttitta, F.; Carron, M.K.; Annell, C.S.

1972-01-01

Fourteen Ivory Coast tektites exhibit a range of bulk indices of refraction of 1.5156 to 1.5217 ?? 0.0004 and of bulk specific gravities of 2.428 to 2.502 ??0.005. Seven of these Ivory Coast (IVC) tektites were analyzed for major and minor element content. Compared to tektites from other strewn fields, their SiO2 content is low (67.2-69.1 %), A12O3 relatively high (15.8-16.8 %), and total iron relatively high but with a more restricted range (6.3-6.8 % as FeO). Their lime content is low (0.71-1.35%) compared to Australasian tektites but their MgO CaO ratio (about 3.1) is unusually high. All other tektite groups have Na2O K2O ratios less than unity, but the Na2O K2O ratio of the IVC tektites is slightly greater than unity. Their K Rb ratios range from 200 to 256 and average 227, which is higher than those determined for Australasian tektites, but similar to some obtained for moldavites. The Li content (41-48 ppm) is about the same as that of the Australasian tektites, but the Cs and Rb are lower, being 1.9 to 2.9 and 57 to 86 ppm, respectively. The IVC tektites are high in Cr (260-375 ppm), Co (19-25 ppm) and Ni (101-167 ppm), and particularly in Pb (<10-18 ppm), Cu (13-21 ppm) and Ga (14-23 ppm). The high Cr Ni ratios of the IVC tektites (range 2-3.6) are similar to those found for australites, philippinites and thailandites, but not the javanites and indochinites. Evaluation of these and other reported data show that compositional similarities between the IVC tektites and green or black Bosumtwi Crater glasses strongly support the hypothesis of a common impact origin-i.e. the Bosumtwi Crater site. Comparison of the IVC tektite composition with those of returned lunar materials (gabbros, basalts, breccia and soils) do not support a lunar origin for the Ivory Coast tektites. ?? 1972.

Partial insanity: when the judiciary and the psychiatric world collide.

PubMed

Altmark, D; Sigal, M; Gelkopf, M

1995-01-01

The psychiatric and judicial concepts of mental disorders are similar but not always identical. The gap between them creates confusion, a lack of unity and inconsistencies in decision making. This gap needs to be bridged. In the hinterland of these concepts lies a range of psychiatric disturbances such as encapsulated over organized delusional disorders (Paranoia Vera) and life endangering eating disorders (Anorexia Nervosa). When life threatening or criminal responsibility circumstances arise, the dilemma presented to the psychiatrists on the one hand and the judicial system on the other reaches its peak. Presented in the article are aspects of the gray areas of involuntary commitment and criminal responsibility.

Land-based air in a national maritime strategy: the need for a joint strategic doctrine. Final report

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

Staley, R.S.

This paper examines the role of land-based air power within a national maritime strategy. Corbett taught that naval strategy is a subsidiary aspect of a national maritime strategy; and the increasing speed, range, and accuracy of aircraft, weapons, detection, and communications ensure that an important part of maritime air control will be land-based. To evaluate that claim, this paper examines the unity of sea control and air control; examines the Air Force missions that affect sea control; discusses the strategic concerns directing land-based air in maritime strategy; and explains why joint strategic doctrine will better integrate our military forces.

Assessing the degree of plug flow in oxidation flow reactors (OFRs): a study on a potential aerosol mass (PAM) reactor

NASA Astrophysics Data System (ADS)

Mitroo, Dhruv; Sun, Yujian; Combest, Daniel P.; Kumar, Purushottam; Williams, Brent J.

2018-03-01

Oxidation flow reactors (OFRs) have been developed to achieve high degrees of oxidant exposures over relatively short space times (defined as the ratio of reactor volume to the volumetric flow rate). While, due to their increased use, attention has been paid to their ability to replicate realistic tropospheric reactions by modeling the chemistry inside the reactor, there is a desire to customize flow patterns. This work demonstrates the importance of decoupling tracer signal of the reactor from that of the tubing when experimentally obtaining these flow patterns. We modeled the residence time distributions (RTDs) inside the Washington University Potential Aerosol Mass (WU-PAM) reactor, an OFR, for a simple set of configurations by applying the tank-in-series (TIS) model, a one-parameter model, to a deconvolution algorithm. The value of the parameter, N, is close to unity for every case except one having the highest space time. Combined, the results suggest that volumetric flow rate affects mixing patterns more than use of our internals. We selected results from the simplest case, at 78 s space time with one inlet and one outlet, absent of baffles and spargers, and compared the experimental F curve to that of a computational fluid dynamics (CFD) simulation. The F curves, which represent the cumulative time spent in the reactor by flowing material, match reasonably well. We value that the use of a small aspect ratio reactor such as the WU-PAM reduces wall interactions; however sudden apertures introduce disturbances in the flow, and suggest applying the methodology of tracer testing described in this work to investigate RTDs in OFRs to observe the effect of modified inlets, outlets and use of internals prior to application (e.g., field deployment vs. laboratory study).

Free-stream static pressure measurements in the Longshot hypersonic wind tunnel and sensitivity analysis

NASA Astrophysics Data System (ADS)

Grossir, Guillaume; Van Hove, Bart; Paris, Sébastien; Rambaud, Patrick; Chazot, Olivier

2016-05-01

The performance of fast-response slender static pressure probes is evaluated in the short-duration, cold-gas, VKI Longshot hypersonic wind tunnel. Free-stream Mach numbers range between 9.5 and 12, and unit Reynolds numbers are within 3-10 × 106/m. Absolute pressure sensors are fitted within the probes, and an inexpensive calibration method, suited to low static pressure environments (200-1000 Pa), is described. Transfer functions relating the probe measurements p w to the free-stream static pressure p ∞ are established for the Longshot flow conditions based on numerical simulations. The pressure ratios p w / p ∞ are found to be close to unity for both laminar and turbulent boundary layers. Weak viscous effects characterized by small viscous interaction parameters {bar{χ }}<1.5 are confirmed experimentally for probe aspect ratios of L/ D > 16.5 by installing multiple pressure sensors in a single probe. The effect of pressure orifice geometry is also evaluated experimentally and found to be negligible for either straight or chamfered holes, 0.6-1 mm in diameter. No sensitivity to probe angle of attack could be evidenced for α < 0.33°. Pressure measurements are compared to theoretical predictions assuming an isentropic nozzle flow expansion. Significant deviations from this ideal case and the Mach 14 contoured nozzle design are uncovered. Validation of the static pressure measurements is obtained by comparing shock wave locations on Schlieren photographs to numerical predictions using free-stream properties derived from the static pressure probes. While these results apply to the Longshot wind tunnel, the present methodology and sensitivity analysis can guide similar investigations for other hypersonic test facilities.

Adult Education in the 90s: Unity in Diversity.

ERIC Educational Resources Information Center

Udagama, Premadasa, Ed.

1991-01-01

This issue of the Asian-South Pacific Bureau of Adult Education (ASPBAE) Courier contains the following contributions related to the theme of unity in the diversity of interests and approaches to adult/informal education: "Unity in Diversity--The Future of Adult Education in Asia and the South-Pacific Region" (Rajesh Tandon); "Notes…

8 CFR 236.18 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 8 Aliens and Nationality 1 2012-01-01 2012-01-01 false Termination of Family Unity Program benefits. 236.18 Section 236.18 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF INADMISSIBLE AND DEPORTABLE ALIENS; REMOVAL OF ALIENS ORDERED REMOVED Family Unity Program § 236.18 Termination of...

8 CFR 236.18 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 8 Aliens and Nationality 1 2013-01-01 2013-01-01 false Termination of Family Unity Program benefits. 236.18 Section 236.18 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF INADMISSIBLE AND DEPORTABLE ALIENS; REMOVAL OF ALIENS ORDERED REMOVED Family Unity Program § 236.18 Termination of...

View of the STS-88 crew in the Node 1/Unity module

NASA Image and Video Library

2013-11-19

STS088-334-012 (4-15 Dec. 1998) --- Astronaut Frederick W. Sturckow, pilot, works with furnishings on the U.S.-built Unity module as he and five crew mates teamed up to prepare Unity and the connected Russian-built Zarya module for their International Space Station (ISS) roles.

8 CFR 236.18 - Termination of Family Unity Program benefits.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 8 Aliens and Nationality 1 2014-01-01 2014-01-01 false Termination of Family Unity Program benefits. 236.18 Section 236.18 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF INADMISSIBLE AND DEPORTABLE ALIENS; REMOVAL OF ALIENS ORDERED REMOVED Family Unity Program § 236.18 Termination of...

Unity hatch closed in preparation for launch on STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

Workers in the Space Station Processing Facility hold part of the equipment to close the hatch to the Unity connecting module, part of the International Space Station, before its launch aboard Space Shuttle Endeavour on STS-88 in December. Unity will now undergo a series of leak checks before a final purge of clean, dry air inside the module to ready it for initial operations in space. Other testing includes the common berthing mechanism to which other space station elements will dock and the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter. The next time the hatch will be opened it will be by astronauts on orbit. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27. The Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time.

Unity hatch closed in preparation for launch on STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

Workers in the Space Station Processing Facility close the access hatch to the Unity connecting module, part of the International Space Station, before its launch aboard Space Shuttle Endeavour on STS-88 in December. Unity will now undergo a series of leak checks before a final purge of clean, dry air inside the module to ready it for initial operations in space. Other testing includes the common berthing mechanism to which other space station elements will dock and the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter. The next time the hatch will be opened it will be by astronauts on orbit. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27. The Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time.

Unity hatch closed in preparation for launch on STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

Workers in the Space Station Processing Facility make final preparations for closing the access hatch to the Unity connecting module, part of the International Space Station, before its launch aboard Space Shuttle Endeavour on STS-88 in December. Unity will now undergo a series of leak checks before a final purge of clean, dry air inside the module to ready it for initial operations in space. Other testing includes the common berthing mechanism to which other space station elements will dock and the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter. The next time the hatch will be opened it will be by astronauts on orbit. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27. The Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time.

Unity hatch closed in preparation for launch on STS-88

NASA Technical Reports Server (NTRS)

1998-01-01

Workers in the Space Station Processing Facility work in the doorway of the Unity connecting module preparing it for closure before its launch aboard Space Shuttle Endeavour on STS-88 in December. Unity will now undergo a series of leak checks before a final purge of clean, dry air inside the module to ready it for initial operations in space. Other testing includes the common berthing mechanism to which other space station elements will dock and the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter. The next time the hatch will be opened it will be by astronauts on orbit. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27. The Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time.

Unity connecting module moving to new site in SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

In the Space Station Processing Facility (SSPF), Unity (top) is suspended in air as it is moved to a new location (bottom left)in the SSPF. To its left is Leonardo, the Italian-built Multi- Purpose Logistics Module to be launched on STS-100. Above Leonardo, visitors watch through a viewing window, part of the visitors tour at the Center. As the primary payload on mission STS-88, scheduled to launch Dec. 3, 1998, Unity will be mated to the Russian-built Zarya control module which should already be in orbit at that time. In the SSPF, Unity is undergoing testing such as the Pad Demonstration Test to verify the compatibility of the module with the Space Shuttle, as well as the ability of the astronauts to send and receive commands to Unity from the flight deck of the orbiter, and the common berthing mechanism to which other space station elements will dock. Unity is expected to be ready for installation into the payload canister on Oct. 25, and transported to Launch Pad 39-A on Oct. 27.

Aspect ratio has no effect on genotoxicity of multi-wall carbon nanotubes.

PubMed

Kim, Jin Sik; Lee, Kyu; Lee, Young Hee; Cho, Hyun Sun; Kim, Ki Heon; Choi, Kyung Hee; Lee, Sang Hee; Song, Kyung Seuk; Kang, Chang Soo; Yu, Il Je

2011-07-01

Carbon nanotubes (CNTs) have specific physico-chemical and electrical properties that are useful for telecommunications, medicine, materials, manufacturing processes and the environmental and energy sectors. Yet, despite their many advantages, it is also important to determine whether CNTs may represent a hazard to the environment and human health. Like asbestos, the aspect ratio (length:diameter) and metal components of CNTs are known to have an effect on the toxicity of carbon nanotubes. Thus, to evaluate the toxic potential of CNTs in relation to their aspect ratio and metal contamination, in vivo and in vitro genotoxicity tests were conducted using high-aspect-ratio (diameter: 10-15 nm, length: ~10 μm) and low-aspect-ratio multi-wall carbon nanotubes (MWCNTs, diameter: 10-15 nm, length: ~150 nm) according to OECD test guidelines 471 (bacterial reverse mutation test), 473 (in vitro chromosome aberration test), and 474 (in vivo micronuclei test) with a good laboratory practice system. To determine the treatment concentration for all the tests, a solubility and dispersive test was performed, and a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) solution found to be more suitable than distilled water. Neither the high- nor the low-aspect-ratio MWCNTs induced any genotoxicity in a bacterial reverse mutation test (~1,000 μg/plate), in vitro chromosome aberration test (without S9: ~6.25 μg/ml, with S9: ~50 μg/ml), or in vivo micronuclei test (~50 mg/kg). However, the high-aspect-ratio MWCNTs were found to be more toxic than the low-aspect-ratio MWCNTs. Thus, while high-aspect-ratio MWCNTs do not induce direct genotoxicity or metabolic activation-mediated genotoxicity, genotoxicity could still be induced indirectly through oxidative stress or inflammation.

Discretization in time gives rise to noise-induced improvement of the signal-to-noise ratio in static nonlinearities.

PubMed

Davidović, A; Huntington, E H; Frater, M R

2009-07-01

For some nonlinear systems the performance can improve with an increasing noise level. Such noise-induced improvement in static nonlinearities is of great interest for practical applications since many systems can be modeled in that way (e.g., sensors, quantizers, limiters, etc.). We present experimental evidence that noise-induced performance improvement occurs in those systems as a consequence of discretization in time with the achievable signal-to-noise ratio (SNR) gain increasing with decreasing ratio of input noise bandwidth and total measurement bandwidth. By modifying the input noise bandwidth, noise-induced improvement with SNR gain larger than unity is demonstrated in a system where it was not previously thought possible. Our experimental results bring closer two different theoretical models for the same class of nonlinearities and shed light on the behavior of static nonlinear discrete-time systems.

Excessive and disproportionate advertising in peer-reviewed journals.

PubMed

Friedman, Lee S; Richter, Elihu D

2006-01-01

The International Committee of Medical Journal Editors (ICMJE) has outlined ethical guidelines concerning the advertising practices of peer-reviewed journals that briefly discuss issues of excessive and disproportionate advertising. The authors evaluated these guidelines using quantitative data, assessing the types and frequencies of advertising in 2001 print issues of NEJM and JAMA, two principal members of ICMJE. Advertising ratios (ratio of advertisements to editorial content) were near unity in NEJM and 0.30 in JAMA, compared with reported ratios of 0.15 among low-circulation specialty science journals and 0.80 among high-circulation consumer magazines. In both journals, five corporations placed more than 50% of all display advertisements. The findings suggest a dissonance between the ethical guidelines and the de facto advertising practices of arguably the two most important member journals of the ICMJE. There is a need to define and apply standards for excessive and disproportionate advertising.

The Node 1 (or Unity) Module for the International Space Station

NASA Technical Reports Server (NTRS)

1997-01-01

This photograph, taken by the Boeing Company,shows Boeing technicians preparing to install one of six hatches or doors to the Node 1 (also called Unity), the first U.S. Module for the International Space Station (ISS). The Node 1, or Unity, serves as a cornecting passageway to Space Station modules and was manufactured by the Boeing Company at the Marshall Space Flight Center from 1994 to 1997. The U.S. built Unity module was launched aboard the orbiter Endeavour (STS-88 mission) on December 4, 1998 and connected to the Zarya, the Russian-built Functional Energy Block (FGB). The Zarya was launched on a Russian proton rocket prior to the launch of the Unity. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation.

The Node 1 (or Unity) Module for the International Space Station

NASA Technical Reports Server (NTRS)

1997-01-01

This photograph, taken by the Boeing Company, shows Boeing technicians preparing to install one of six hatches or doors to the Node 1 (also called Unity), the first U.S. Module for the International Space Station (ISS). The Node 1, or Unity, serves as a cornecting passageway to Space Station modules and was manufactured by the Boeing Company at the Marshall Space Flight Center from 1994 to 1997. The U.S. built Unity module was launched aboard the orbiter Endeavour (STS-88 mission) on December 4, 1998 and connected to the Zarya, the Russian-built Functional Energy Block (FGB). The Zarya was launched on a Russian proton rocket prior to the launch of the Unity. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation.

Synthesis of high aspect ratio ZnO nanowires with an inexpensive handcrafted electrochemical setup

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

Taheri, Ali, E-mail: at1361@aut.ac.ir, E-mail: atahery@aeoi.org.ir; Saramad, Shahyar; Setayeshi, Saeed

In this work, high aspect ratio zinc oxide nanowires are synthesized using templated one-step electrodeposition technique. Electrodeposition of the nanowires is done using a handcrafted electronic system. Nuclear track-etched polycarbonate membrane is used as a template to form the high aspect ratio nanowires. The result of X-ray diffraction and scanning electron microscopy shows that nanowires with a good crystallinity and an aspect ratio of more than 30 can be achieved in a suitable condition. The height of electrodeposited nanowires reaches to about 11 μm. Based on the obtained results, high aspect ratio ZnO nanowires can be formed using inexpensive electrodepositionmore » setup with an acceptable quality.« less

Cultural Aspects of Astrobiology: A Preliminary Reconnaissance at

NASA Astrophysics Data System (ADS)

Dick, Steven

NASA's Astrobiology Roadmap, developed in 1998 by an interdisciplinary team of more than 150 individuals, recognizes ten science goals, 17 more specific science objectives, and four broad principles for the Astrobiology Program. Among the four operating principles, which emphasize multidisciplinarity, planetary stewardship and public outreach, is one that also recognizes broad societal interest for the implications of astrobiology, especially its extraterrestrial life component. Although several meetings ahve been convened in the past decade to discuss the implications of extraterrestrial intelligence, including NASA's own CASETI workshops in 1991-1992, none have surveyed the broader implications of astrobiology as now defined at NASA. In this paper we survey these societal questions raised by astrobiology, and then focus on those related to extraterrestrial life, and in particular how they might differ from SETI concerns already discussed. As we enter the new millennium, the necessity for interdisciplinary studies is increasingly recognized in academia, industry and government. Astrobiology provides an unprecedented opportunity to encourage the unity of knowledge, as recently proposed in E. O. Wilson's book Consilience: The Unity of Knowledge. It is incumbent on scientists to support research on the implications of their work, in particular large government-funded scientific projects. The deep insights such study may yield has been amply demonstrated by the Human Genome Project, among others.

37 CFR 1.499 - Unity of invention during the national stage.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Unity of invention during the national stage. 1.499 Section 1.499 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE GENERAL RULES OF PRACTICE IN PATENT CASES International Processing Provisions National Stage § 1.499 Unity of...

37 CFR 1.499 - Unity of invention during the national stage.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Unity of invention during the national stage. 1.499 Section 1.499 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE GENERAL RULES OF PRACTICE IN PATENT CASES International Processing Provisions National Stage § 1.499 Unity of...

37 CFR 1.499 - Unity of invention during the national stage.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Unity of invention during the national stage. 1.499 Section 1.499 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE GENERAL RULES OF PRACTICE IN PATENT CASES International Processing Provisions National Stage § 1.499 Unity of...

37 CFR 1.499 - Unity of invention during the national stage.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Unity of invention during the national stage. 1.499 Section 1.499 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE GENERAL RULES OF PRACTICE IN PATENT CASES International Processing Provisions National Stage § 1.499 Unity of...

A comprehensive approach to environmental and human factors into product/service design and development. A review from an ergoecological perspective.

PubMed

Saravia-Pinilla, Martha H; Daza-Beltrán, Carolina; García-Acosta, Gabriel

2016-11-01

This article presents the results of a documentary-exploratory review of design methods and concepts associated with human and environmental factors, based on a qualitative-quantitative analysis of coincidences with the fundamentals of ergoecology and in line with sustainable dynamics, with a view to putting the principles of ergoecology into practice in product/service design and development. 61.6% of 696 documents found represent work on conceptual developments, while the remaining 38.4% refer to design methods. Searches were refined using Nvivo-10 software, and 101 documents were obtained about theoretical aspects while 17 focused on the application of methods, and these formed the analysis universe. The results show how little concern there is for working comprehensively on human and environmental aspects, and a trend toward segmentation of human and environmental aspects in the field of product/service design and development can be seen, at both concept and application/methodology levels. It was concluded from the above that comprehensive, simultaneous work is needed on human and environmental aspects, clarity and conceptual unity, in order to achieve sustainability in practical matters and ensure that ergoecology-compatible design methods are applied. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Effect of Roughness Model on Scattering Properties of Ice Crystals.

NASA Technical Reports Server (NTRS)

Geogdzhayev, Igor V.; Van Diedenhoven, Bastiaan

2016-01-01

We compare stochastic models of microscale surface roughness assuming uniform and Weibull distributions of crystal facet tilt angles to calculate scattering by roughened hexagonal ice crystals using the geometric optics (GO) approximation. Both distributions are determined by similar roughness parameters, while the Weibull model depends on the additional shape parameter. Calculations were performed for two visible wavelengths (864 nm and 410 nm) for roughness values between 0.2 and 0.7 and Weibull shape parameters between 0 and 1.0 for crystals with aspect ratios of 0.21, 1 and 4.8. For this range of parameters we find that, for a given roughness level, varying the Weibull shape parameter can change the asymmetry parameter by up to about 0.05. The largest effect of the shape parameter variation on the phase function is found in the backscattering region, while the degree of linear polarization is most affected at the side-scattering angles. For high roughness, scattering properties calculated using the uniform and Weibull models are in relatively close agreement for a given roughness parameter, especially when a Weibull shape parameter of 0.75 is used. For smaller roughness values, a shape parameter close to unity provides a better agreement. Notable differences are observed in the phase function over the scattering angle range from 5deg to 20deg, where the uniform roughness model produces a plateau while the Weibull model does not.

Numerical analysis of the angular motion of a neutrally buoyant spheroid in shear flow at small Reynolds numbers.

PubMed

Rosén, T; Einarsson, J; Nordmark, A; Aidun, C K; Lundell, F; Mehlig, B

2015-12-01

We numerically analyze the rotation of a neutrally buoyant spheroid in a shear flow at small shear Reynolds number. Using direct numerical stability analysis of the coupled nonlinear particle-flow problem, we compute the linear stability of the log-rolling orbit at small shear Reynolds number Re(a). As Re(a)→0 and as the box size of the system tends to infinity, we find good agreement between the numerical results and earlier analytical predictions valid to linear order in Re(a) for the case of an unbounded shear. The numerical stability analysis indicates that there are substantial finite-size corrections to the analytical results obtained for the unbounded system. We also compare the analytical results to results of lattice Boltzmann simulations to analyze the stability of the tumbling orbit at shear Reynolds numbers of order unity. Theory for an unbounded system at infinitesimal shear Reynolds number predicts a bifurcation of the tumbling orbit at aspect ratio λ(c)≈0.137 below which tumbling is stable (as well as log rolling). The simulation results show a bifurcation line in the λ-Re(a) plane that reaches λ≈0.1275 at the smallest shear Reynolds number (Re(a)=1) at which we could simulate with the lattice Boltzmann code, in qualitative agreement with the analytical results.

A three-dimensional finite element model of human atrial anatomy: New methods for cubic Hermite meshes with extraordinary vertices

PubMed Central

Gonzales, Matthew J.; Sturgeon, Gregory; Krishnamurthy, Adarsh; Hake, Johan; Jonas, René; Stark, Paul; Rappel, Wouter-Jan; Narayan, Sanjiv M.; Zhang, Yongjie; Segars, W. Paul; McCulloch, Andrew D.

2013-01-01

High-order cubic Hermite finite elements have been valuable in modeling cardiac geometry, fiber orientations, biomechanics, and electrophysiology, but their use in solving three-dimensional problems has been limited to ventricular models with simple topologies. Here, we utilized a subdivision surface scheme and derived a generalization of the “local-to-global” derivative mapping scheme of cubic Hermite finite elements to construct bicubic and tricubic Hermite models of the human atria with extraordinary vertices from computed tomography images of a patient with atrial fibrillation. To an accuracy of 0.6 millimeters, we were able to capture the left atrial geometry with only 142 bicubic Hermite finite elements, and the right atrial geometry with only 90. The left and right atrial bicubic Hermite meshes were G1 continuous everywhere except in the one-neighborhood of extraordinary vertices, where the mean dot products of normals at adjacent elements were 0.928 and 0.925. We also constructed two biatrial tricubic Hermite models and defined fiber orientation fields in agreement with diagrammatic data from the literature using only 42 angle parameters. The meshes all have good quality metrics, uniform element sizes, and elements with aspect ratios near unity, and are shared with the public. These new methods will allow for more compact and efficient patient-specific models of human atrial and whole heart physiology. PMID:23602918

STS-88 Onboard Photograph - The Unity Module and the Zarya

NASA Technical Reports Server (NTRS)

1998-01-01

This photograph taken during the STS-88 mission, shows the cornected Zarya (top with solar wings) and the Unity Module after having been released from the Orbiter Endeavour's cargo bay. The Unity (also called Node 1), the first U.S. Module for the International Space Station (ISS), is a six-sided connector to which all future U.S. Station modules will attach and was manufactured by the Boeing Company at the Marshall Space Flight Center from 1994 to 1997. The U.S. built Unity module was launched aboard the orbiter Endeavour (STS-88 mission) on December 4, 1998 and connected to the Zarya, the Russian built Functional Energy Block (FGB). The Zarya was launched on a Russian proton rocket prior to the launch of the Unity. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation.

STS-88 Onboard Photograph - Unity and Zarya Modules

NASA Technical Reports Server (NTRS)

1998-01-01

This photograph, taken during the STS-88 mission, shows the cornected Unity Module or Node 1 and Zarya or the Functional Cargo Block (FGB) after having been released from the Orbiter Endeavour's cargo bay. The Unity (also called Node 1), the first U.S. Module for the International Space Station (ISS), is a six-sided connector to which all future U.S. Station modules will attach. It was manufactured by the Boeing Company at the Marshall Space Flight Center from 1994 to 1997. The U.S. built Unity Module was launched aboard the orbiter Endeavour (STS-88 mission) on December 4, 1998 and connected to the Zarya, the Russian built Functional Energy Block (FGB). The Zarya was launched on a Russian proton rocket prior to the launch of the Unity. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation.

Studying aerosol light scattering based on aspect ratio distribution observed by fluorescence microscope.

PubMed

Li, Li; Zheng, Xu; Li, Zhengqiang; Li, Zhanhua; Dubovik, Oleg; Chen, Xingfeng; Wendisch, Manfred

2017-08-07

Particle shape is crucial to the properties of light scattered by atmospheric aerosol particles. A method of fluorescence microscopy direct observation was introduced to determine the aspect ratio distribution of aerosol particles. The result is comparable with that of the electron microscopic analysis. The measured aspect ratio distribution has been successfully applied in modeling light scattering and further in simulation of polarization measurements of the sun/sky radiometer. These efforts are expected to improve shape retrieval from skylight polarization by using directly measured aspect ratio distribution.

Effects of Variable Aspect-Ratio Inclusions on the Electrical Impedance of an Alumina Zirconia Composite at Intermediate Temperatures

NASA Technical Reports Server (NTRS)

Goldsby, Jon C.

2010-01-01

A series of alumina-yttria-stabilized zirconia composites containing either a high aspect ratio (5 and 30 mol%) hexagonal platelet alumina or an alumina low aspect ratio (5 and 30 mol%) spherical particulate was used to determine the effect of the aspect ratio on the temperature-dependent impedance of the composite material. The highest impedance across the temperature range of 373 to 1073 K is attributed to the grain boundary of the hexagonal platelet second phase in this alumina zirconia composite.

Simulation and experimental study of aspect ratio limitation in Fresnel zone plates for hard-x-ray optics.

PubMed

Liu, Jianpeng; Shao, Jinhai; Zhang, Sichao; Ma, Yaqi; Taksatorn, Nit; Mao, Chengwen; Chen, Yifang; Deng, Biao; Xiao, Tiqiao

2015-11-10

For acquiring high-contrast and high-brightness images in hard-x-ray optics, Fresnel zone plates with high aspect ratios (zone height/zone width) have been constantly pursued. However, knowledge of aspect ratio limits remains limited. This work explores the achievable aspect ratio limit in polymethyl methacrylate (PMMA) by electron-beam lithography (EBL) under 100 keV, and investigates the lithographic factors for this limitation. Both Monte Carlo simulation and EBL on thick PMMA are applied to investigate the profile evolution with exposure doses over 100 nm wide dense zones. A high-resolution scanning electron microscope at low acceleration mode for charging free is applied to characterize the resultant zone profiles. It was discovered for what we believe is the first time that the primary electron-beam spreading in PMMA and the proximity effect due to extra exposure from neighboring areas could be the major causes of limiting the aspect ratio. Using the optimized lithography condition, a 100 nm zone plate with aspect ratio of 15/1 was fabricated and its focusing property was characterized at the Shanghai Synchrotron Radiation Facility. The aspect ratio limit found in this work should be extremely useful for guiding further technical development in nanofabrication of high-quality Fresnel zone plates.

Catadioptric optics for laser Doppler velocimeter applications

NASA Technical Reports Server (NTRS)

Dunagan, Stephen E.

1989-01-01

This paper examines the adaptation of low-cost Schmidt-Cassegrain astronomical telescopes to perform the laser-beam-focusing and scattered-light collection tasks associated with dual-beam laser Doppler velocimetry. A generic telescope design is analyzed using ray-tracing methods and Gaussian beam-propagation theory. A straightforward modification procedure to convert from infinite to near unity conjugate-ratio operation with very low residual aberration is identified and tested with a 200-mm-aperture telescope modified for f/10 operation. Performance data for this modified telescope configuration are near the diffraction limit and agree well with predictions.

Arsine flow requirement for the flow modulation growth of high purity GaAs using adduct-grade triethylgallium

NASA Astrophysics Data System (ADS)

Pitts, B. L.; Emerson, D. T.; Shealy, J. R.

1992-10-01

Using arsine and triethylgallium with flow modulation, organometallic vapor phase epitaxy can produce high purity GaAs layers with V/III molar ratios near unity. We have estimated that under appropriate growth conditions the arsine incorporation efficiency into epitaxial GaAs can exceed 30%. The arsine flow requirement for obtaining good morphology has been identified over a range of substrate temperatures using adduct-grade triethylgallium. The process described reduces the environmental impact and life safety risk of the hydride based organometallic vapor phase epitaxial method.

An analytical study of the effect of coolant flow variables on the kinetic energy output of a cooled turbine blade row.

NASA Technical Reports Server (NTRS)

Prust, H. W., Jr.

1972-01-01

Demonstration that the change in output of a cooled turbine blade row relative to the specific output of the uncooled blade row can be positive, negative, or zero, depending on the velocity, injection location, injection angle, and temperature of the coolant. Comparisons between the analytical results and experimental results for four different cases of coolant discharge, all at a coolant temperature ratio of unity, show good agreement for three cases, and rather poor agreement for the other.

On the distinction between large deformation and large distortion for anisotropic materials

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

BRANNON,REBECCA M.

2000-02-24

A motion involves large distortion if the ratios of principal stretches differ significantly from unity. A motion involves large deformation if the deformation gradient tensor is significantly different from the identity. Unfortunately, rigid rotation fits the definition of large deformation, and models that claim to be valid for large deformation are often inadequate for large distortion. An exact solution for the stress in an idealized fiber-reinforced composite is used to show that conventional large deformation representations for transverse isotropy give errant results. Possible alternative approaches are discussed.

Gas and Dust Structures of the Protoplanetary Disk around HD 142527

NASA Astrophysics Data System (ADS)

Momose, M.; Muto, T.; Hanawa, T.; Fukagawa, M.; Tsukagoshi, T.; Saigo, K.; Kataoka, A.; Nomura, H.; Takeuchi, T.; Akiyama, E.; Ohashi, N.; Fujiwara, H.; Shibai, H.; Kitamura, Y.; Inutsuka, S.; Kobayashi, H.; Honda, M.; Aso, Y.; Takahashi, S. Z.

2015-12-01

HD142527 is a Herbig Fe star accompanied by a disk with ring-like structure. We derive the distributions of dust and gas separately by model fitting and discuss the spatial variation of gas-to-dust mass ratio in the disk. The radial distribution of dust is well approximated by a Gaussian function, while the gas is roughly followed by a power-law distribution between 110 and 400 AU in radius, which is significantly more extended than dust. G/d may reach the order of unity at the northern peak.

Isotopic tracing of the dissolved U fluxes of Himalayan rivers: implications for present and past U budgets of the Ganges-Brahmaputra system

NASA Astrophysics Data System (ADS)

Chabaux, François; Riotte, Jean; Clauer, Norbert; France-Lanord, Christian

2001-10-01

U activity ratios have been measured in the dissolved loads of selected rivers from the Himalayan range, in Central Nepal, and from the Bangladesh, as well as in some rain waters. A few European and Asian rivers have also been analyzed for their U activity ratios. The data confirm the negligible effect of rainwater on the budget of dissolved U in river waters. The results also indicate that rivers on each Himalayan structural unit have homogeneous and specific U isotope compositions: i) (234U/238U) activity ratios slightly lower than unity in the dissolved load of the streams draining the Tethyan Sedimentary Series (TSS); ii) values slightly higher than unity for waters from the High Himalaya Crystalline (HHC) and the Lesser Himalaya (LH); iii) systematically higher (234U/238U) activity ratios for waters from the Siwaliks. Thus, U activity ratios, in association with Sr isotopic ratios, can be used to trace the sources of dissolved fluxes carried by these rivers. Coupling of U with Sr isotope data shows (1) that the U carried by the dissolved load of the Himalayan rivers mainly originates from U-rich lithologies of the TSS in the northern formations of the Tibetan plateau; and (2) that the elemental U and Sr fluxes carried by the Himalayan rivers at the outflow of the highlands are fairly homogeneous at the scale of the Himalayan chain. Rivers flowing on the Indian plain define a different trend from that of the Himalayan rivers in the U-Sr isotopic diagram, indicating the contribution of a specific floodplain component to the U and Sr budgets of the Ganges and the Brahmaputra. The influence of this component remains limited to 10 to 15 percent for the U flux, but can contribute 35 to 55% of the Sr flux. The variations of the Sr and U fluxes of the Ganges-Brahmaputra river system in response to climatic variations have been estimated by assuming a temporary cut off of the chemical fluxes from high-altitude terrains during glacial episodes. This scenario would significantly decrease the dissolved U flux of the Ganges-Brahmaputra river system and increase its U activity ratio. Such a climatic dependence of the Himalayan U flux could induce a periodic variation of the mean U activity ratio of the world rivers on glacial-interglacial timescales

Impact of Aspect Ratio, Incident Angle, and Surface Roughness on Windbreak Wakes

NASA Astrophysics Data System (ADS)

Tobin, Nicolas; Chamorro, Leonardo P.

2017-11-01

Wind-tunnel results are presented on the wakes behind three-dimensional windbreaks in a simulated atmospheric boundary layer. Sheltering by upwind windbreaks, and surface-mounted obstacles (SMOs) in general, is parameterized by the wake-moment coefficient C h , which is a complex function of obstacle geometry and flow conditions. Values of C h are presented for several windbreak aspect ratios, incident angles, and windbreak-height-to-surface-roughness ratios. Lateral wake deflection is further presented for several incident angles and aspect ratios, and compared to a simple analytical formulation including a near- and far-wake solution. It is found that C h does not change with aspect ratios of 10 or greater, though C h may be lower for an aspect ratio of 5. C h is found to change roughly with the cosine of the incident angle, and to depend strongly on windbreak-height-to-surface-roughness ratio. The data broadly support the proposed wake-deflection model.

Potential Moderating Effects of Selenium on Mercury Uptake and Selenium:Mercury Molar Ratios in Fish From Oak Ridge and Savannah River Site - 12086

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

Burger, Joanna; Gochfeld, Michael; Donio, Mark

2012-07-01

Mercury contamination is an important remediation issue at the U.S. Department of Energy's (DOE) Oak Ridge Reservation and to a lesser extent at other DOE sites because of the hazard it presents, potential consequences to humans and eco-receptors, and completed pathways, to offsite receptors. Recent work has emphasized that selenium might ameliorate the toxicity of mercury, and we examine the selenium:mercury (Se:Hg) molar ratios in fish from Oak Ridge, and compare them to Se:Hg molar ratios in fish from the Savannah River. Selenium/mercury molar ratios varied considerably among and within fish species. There was considerable variation in the molar ratiosmore » for individual fish (as opposed to mean ratios by species) for freshwater fish from both sites. The inter-individual variation in molar ratios indicates that such that the molar ratios of mean Se and Hg concentrations may not be representative. Even for fish species with relatively low mercury levels, some individual fish have molar ratios less than unity, the value sometime thought to be protective. Selenium levels varied narrowly regardless of fish size, consistent with homeostatic regulation of this essential trace element. The data indicate that considerable attention will need to be directed toward variations and variances, as well as the mechanisms of the interaction of selenium and mercury, before risk assessment and risk management policies can use this information to manage mercury pollution and risk. Even so, if there are high levels of selenium in the fish from Poplar Creek on Oak Ridge, then the potential exists for some amelioration of adverse health effects, on the fish themselves, predators that eat them, and people who consume them. This work will aid DOE because it will allow managers and scientists to understand another aspect that affects fate and transport of mercury, as well as the potential effects of methylmercury in fish for human and ecological receptors. The variability within fish species, however, suggests that the relative Se:Hg molar ratios in fish are not stable enough to be used in risk assessment at this time. Nor is it known how much excess selenium is required to confer any degree of protectiveness. That is, in conducting risk assessments, it is not possible to determine the spread of ratios, which would be needed for probabilistic risk assessment. Significantly more fish samples per species are required to begin to generate data that would allow it use in risk assessment. Adding Se:Hg molar ratios seems to complicate risk assessment for the potential adverse effects of mercury exposure, and using mercury levels at this time remains the most viable option. (authors)« less

Some Thoughts about Literature as a Means of Advancing Sustainable Unity and Stability in the Contemporary Nigerian State

ERIC Educational Resources Information Center

Anaso, George Nwaorah; Nwabudike, Christopher Eziafa

2014-01-01

An in-depth investigation was conducted on the possibility of literature employed to enhance cohesion, sustainable unity, national stability, and security of lives and property in the contemporary Nigeria. These three elements--unity, national stability, and security of lives and property are considered the key pillars of a modern state, the…

Stigma Reduction Among African American Women with HIV: UNITY Health Study.

PubMed

Rao, Deepa; Kemp, Christopher G; Huh, David; Nevin, Paul E; Turan, Janet; Cohn, Susan E; Simoni, Jane M; Andrasik, Michele; Molina, Yamile; Mugavero, Michael J; French, Audrey L

2018-03-08

African American women encounter disproportionately high rates of HIVrelated morbidity and mortality which is partially mediated through stigma and its effect on HIV treatment adherence. To assess the effect of the UNITY peer support workshop on HIV-related stigma among African American women living with HIV, compared to a time and attention control group. African American women living with HIV were randomized to the UNITY workshop or a breast cancer education control group. Interventions took place in HIV clinics in Chicago, IL and Birmingham, AL. Participants self-reported HIV-related stigma and social support at baseline, post-workshop, and 4 follow-up visits over 12 months. 239 participants (UNITY n=124; breast cancer education n=115) were assessed over one year. Both arms experienced decreases in mean stigma scores over time. Our model estimated that allocation to UNITY was not associated with a significant difference in stigma points over time. Post-hoc analysis suggested that preceding increases in perceived social support are associated with decreased HIVrelated stigma in this population. Although UNITY did not significantly reduce HIV-related stigma in this population, our findings suggest that social support may be key to HIV-related stigma reduction.

Thermo-mechanical properties of high aspect ratio silica nanofiber filled epoxy composites

NASA Astrophysics Data System (ADS)

Ren, Liyun

The optimization of thermo-mechanical properties of polymer composites at low filler loadings is of great interest in both engineering and scientific fields. There have been several studies on high aspect ratio fillers as novel reinforcement phase for polymeric materials. However, facile synthesis method of high aspect ratio nanofillers is limited. In this study, a scalable synthesis method of high aspect ratio silica nanofibers is going to be presented. I will also demonstrate that the inclusion of high aspect ratio silica nanofibers in epoxy results in a significant improvement of epoxy thermo-mechanical properties at low filler loadings. With silica nanofiber concentration of 2.8% by volume, the Young's modulus, ultimate tensile strength and fracture toughness of epoxy increased ~23, ~28 and ~50%, respectively, compared to unfilled epoxy. At silica nanofiber volume concentration of 8.77%, the thermal expansion coefficient decreased by ˜40% and the thermal conductivity was improved by ˜95% at room temperature. In the current study, the influence of nano-sized silica filler aspect ratio on mechanical and thermal behavior of epoxy nanocomposites were studied by comparing silica nanofibers to spherical silica nanoparticles (with aspect ratio of one) at various filler loadings. The significant reinforcement of composite stiffness is attributed to the variation of the local stress state in epoxy due to the high aspect ratio of the silica nanofiber and the introduction of a tremendous amount of interfacial area between the nanofillers and the epoxy matrix. The fracture mechanisms of silica nanofiber filled epoxy were also investigated. The existence of high aspect ratio silica nanofiber promotes fracture energy dissipation by crack deflection, crack pinning as well as debonding with fiber pull-out leading to enhanced fracture toughness. High aspect ratio fillers also provide significant reduction of photon scattering due to formation of a continuous fiber network within the composite. The resulting silica nanofiber filled epoxy would be widely applicable as underfill and encapsulant in advanced electronic packaging industry because of its electrically insulating, low cost and ease of processability.

Micro-structure and motion of two-dimensional dense short spherocylinder liquids

NASA Astrophysics Data System (ADS)

Wang, Wen; Lin, Jyun-Ting; Su, Yen-Shuo; I, Lin

2018-03-01

We numerically investigate the micro-structure and motion of 2D liquids composed of dense short spherocylinders, by reducing the shape aspect ratio from 3. It is found that reducing shape aspect ratio from 3 causes a smooth transition from heterogeneous structures composed of crystalline ordered domains with good tetratic alignment order to those with good hexagonal bond-orientational order at an aspect ratio equaling 1.35. In the intermediate regime, both structural orders are strongly deteriorated, and the translational hopping rate reaches a maximum due to the poor particle interlocking of the disordered structure. Shortening rod length allows easier rotation, induces monotonic increase of rotational hopping rates, and resumes the separation of rotational and translational hopping time scales at the small aspect ratio end, after the crossover of their rates in the intermediate regime. At the large shape aspect ratio end, the poor local tetratic order has the same positive effects on facilitating local rotational and translational hopping. In contrast, at the small shape aspect ratio end, the poor local bond orientational order has the opposite effects on facilitating local rotational and translational hopping.

Schottky x-ray detectors based on a bulk β-Ga2O3 substrate

NASA Astrophysics Data System (ADS)

Lu, Xing; Zhou, Leidang; Chen, Liang; Ouyang, Xiaoping; Liu, Bo; Xu, Jun; Tang, Huili

2018-03-01

β-Ga2O3 Schottky barrier diodes (SBDs) have been fabricated on a bulk (100) β-Ga2O3 substrate and tested as X-ray detectors in this study. The devices exhibited good rectification properties, such as a high rectification ratio and a close-to-unity ideality factor. A high photo-to-dark current ratio exceeding 800 was achieved for X-ray detection, which was mainly attributed to the low reverse leakage current in the β-Ga2O3 SBDs. Furthermore, transient response of the β-Ga2O3 X-ray detectors was investigated, and two different detection mechanisms, photovoltaic and photoconductive, were identified. The results imply the great potential of β-Ga2O3 based devices for X-ray detection.

Radiological properties of plastics and TLD materials its application in radiation dosimetry

NASA Astrophysics Data System (ADS)

Jabaseelan Samuel, E. James; Srinivasan, K.; Poopathi, V.

2017-05-01

In the current study, we evaluated the tissue equivalency of nine different commonly used thermoluminescence compounds and six plastic materials over the photon energy range of 15 KeV to 20 MeV. Our result confirmed that the ratio of number of electrons per gram, electron density of the entire TLD compounds and plastic materials to ICRU-44 soft tissue was lesser than unity, except in the case of polypropylene plastics. The effective atomic number ratio of all the plastic materials was also <1 excluding Poly-vinyl-chloride, and for TLD lithium borate material, it was <1 others which showed the deviation with respect to photon energy. Mass attenuation coefficient (µ/ϼ), mass absorption coefficient (µen/ρ) was calculated and the results are discussed in this paper.

Large Eddy Simulation of a Film Cooling Flow Injected from an Inclined Discrete Cylindrical Hole into a Crossflow with Zero-Pressure Gradient Turbulent Boundary Layer

NASA Technical Reports Server (NTRS)

Johnson, Perry L.; Shyam, Vikram

2012-01-01

A Large Eddy Simulation (LES) is performed of a high blowing ratio (M = 1.7) film cooling flow with density ratio of unity. Mean results are compared with experimental data to show the degree of fidelity achieved in the simulation. While the trends in the LES prediction are a noticeable improvement over Reynolds-Averaged Navier-Stokes (RANS) predictions, there is still a lack a spreading on the underside of the lifted jet. This is likely due to the inability of the LES to capture the full range of influential eddies on the underside of the jet due to their smaller structure. The unsteady structures in the turbulent coolant jet are also explored and related to turbulent mixing characteristics

An analytical study of the effect of coolant flow variables on the kinetic energy output of a cooled turbine blade flow

NASA Technical Reports Server (NTRS)

Prust, H. W., Jr.

1971-01-01

The results of an analytical study to determine the effect of changes in the amount, velocity, injection location, injection angle, and temperature of coolant flow on blade row performance are presented. The results show that the change in output of a cooled turbine blade row relative to the specific output of the uncooled blade row can be positive, negative, or zero. Comparisons between the analytical results and experimental results for four different cases of coolant discharge, all at a coolant temperature ratio of unity, show good agreement for three cases and rather poor agreement for the other. To further test the validity of the method, more experimental data is needed, particularly at different coolant temperature ratios.

Prospects of neutral Higgs boson decays in the NMSSM

NASA Astrophysics Data System (ADS)

Almarashi, M. M.

2018-06-01

In this paper, we present the branching ratios of the two lightest CP-even Higgses, h1 and h2 , and the lightest CP-odd Higgs, a1 , in the context of the Next-to-Minimal Supersymmetric Standard Model (NMSSM). We find that for some regions of the parameter space, the branching fractions of a1 into the lightest charginos (a1 → χ1+ χ1-) and neutralinos (a1 → χ1SUP>/0SUP> χ10) are larger than 50 % , and can reach a 100 % level in the latter case. Furthermore, the branching ratio of the h2 →a1a1 can be equal to unity for all h2 masses when it is a pure singlet. The above unusual channels are hallmarks of the existence of the NMSSM.

Global dynamics of zooplankton and harmful algae in flowing habitats

NASA Astrophysics Data System (ADS)

Hsu, Sze-Bi; Wang, Feng-Bin; Zhao, Xiao-Qiang

This paper is devoted to the study of two advection-dispersion-reaction models arising from the dynamics of harmful algae and zooplankton in flowing-water habitats where a main channel is coupled to a hydraulic storage zone, representing an ensemble of fringing coves on the shoreline. For the system modeling the dynamics of algae and their toxin that contains little limiting nutrient, we establish a threshold type result on the global attractivity in terms of the basic reproduction ratio for algae. For the model with zooplankton that eat the algae and are inhibited by the toxin produced by algae, we show that there exists a coexistence steady state and the zooplankton is uniformly persistent provided that two basic reproduction ratios for algae and zooplankton are greater than unity.

Effects of flexibility and aspect ratio on the aerodynamic performance of flapping wings.

PubMed

Fu, Junjiang; Liu, Xiaohui; Shyy, Wei; Qiu, Huihe

2018-03-14

In the current study, we experimentally investigated the flexibility effects on the aerodynamic performance of flapping wings and the correlation with aspect ratio at angle of attack α  =  45°. The Reynolds number based on the chord length and the wing tip velocity is maintained at Re  =  5.3  ×  10 3 . Our result for compliant wings with an aspect ratio of 4 shows that wing flexibility can offer improved aerodynamic performance compared to that of a rigid wing. Flexible wings are found to offer higher lift-to-drag ratios; in particular, there is significant reduction in drag with little compromise in lift. The mechanism of the flexibility effects on the aerodynamic performance is addressed by quantifying the aerodynamic lift and drag forces, the transverse displacement on the wings and the flow field around the wings. The regime of the effective stiffness that offers improved aerodynamic performance is quantified in a range of about 0.5-10 and it matches the stiffness of insect wings with similar aspect ratios. Furthermore, we find that the aspect ratio of the wing is the predominant parameter determining the flexibility effects of compliant wings. Compliant wings with an aspect ratio of two do not demonstrate improved performance compared to their rigid counterparts throughout the entire stiffness regime investigated. The correlation between wing flexibility effects and the aspect ratio is supported by the stiffness of real insect wings.

Hierarchical Task Network Prototyping In Unity3d

DTIC Science & Technology

2016-06-01

visually debug. Here we present a solution for prototyping HTNs by extending an existing commercial implementation of Behavior Trees within the Unity3D game ...HTN, dynamic behaviors, behavior prototyping, agent-based simulation, entity-level combat model, game engine, discrete event simulation, virtual...commercial implementation of Behavior Trees within the Unity3D game engine prior to building the HTN in COMBATXXI. Existing HTNs were emulated within

Dynamic UNITY

DTIC Science & Technology

2002-01-01

UNITY program that implements exactly the same algorithm as Specification 1.1. The correctness of this program is proven in amanner sim- 4 program...chapter, we introduce the Dynamic UNITY formalism, which allows us to reason about algorithms and protocols in which the sets of participating processes...implements Euclid’s algorithm for calculating the greatest common divisor (GCD) of two integers; it repeat- edly reads an integer message from each of its

How Can Multi-Campus Community Colleges Hold on to a Sense of Unity and Oneness?

ERIC Educational Resources Information Center

Robinson, Shawn

This paper discusses fostering a sense of unity across multiple campuses of a community college. It defines multi-campus community colleges (M3C) as a community college district composed of more than one site where learning is to take place. Unity is considered the state at which the students, faculty, and staff on the various college campuses and…

77 FR 74265 - In the Matter of the Designation of Movement for Unity and Jihad in West Africa; Also Known as...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-13

... DEPARTMENT OF STATE [Public Notice 8114] In the Matter of the Designation of Movement for Unity and Jihad in West Africa; Also Known as Movement for Oneness and Jihad in West Africa; Also Known as Unity Movement for Jihad in West Africa; Also Known as Jamat Tawhid Wal Jihad Fi Garbi Afriqqiya; Also...

Node 1 / Unity and FGB / Zarya Nadir (+ZA) view during docked operations

NASA Image and Video Library

2013-11-19

STS088-363-023 (4-15 Dec. 1998) --- Wires and cables on the Unity module (foreground) are telltale clues that the space walking astronauts of STS-88 had performed their first extravehicular activity (EVA) when this 35mm frame was exposed from the aft windows of Endeavour. The Zarya module can be seen mated to the top end of Unity.

STS-120 and Expedition 16 Commanders in Node 1/Unity module

NASA Image and Video Library

2007-11-04

S120-E-008350 (4 Nov. 2007) --- Astronauts Pam Melroy (foreground), STS-120 commander; and Peggy Whitson, Expedition 16 commander, add the STS-120 crew patch in the Unity node to the growing collection of those representing shuttle crews who have worked on the International Space Station. A location in the Unity node serves as one of the traditional posting sites for the patches.

[Ressignification of life of caregivers of elderly patients with cancer].

PubMed

dos Anjos, Anna Cláudia Yokoyama; Zago, Márcia Maria Fontão

2014-01-01

The study aimed to analyze the process of becoming a caregiver of elderly patients with cancer, in chemotherapy, in the home context. This is an exploratory study with theoretical and methodological orientation of interpretative anthropology and ethnographic case study. Data were collected from January to September 2009, with four caregivers through semi-structured interviews, observation and consultation records. With data analysis were built four units of meaning. In this paper 'we are focusing the thematic unity "The ressignification of caregiver's life", composed by positive aspects of caregiving activities and of helping to overcome difficulties, such as union, solidarity, opportunity for reapproximation. The difficulties were more evident, especially being unprepared to care at home, which led to changes in the caregiver's familiar and social relationships, resulting in impairment of physical, emotional and social aspects. The nurse, as an agent of care, must provide adequate qualification to the caregivers, helping them in coping with the disease and improving the patient-caregiver-service relationship.

Report of the panel on theoretical aerodynamics. [for the National Transonic Facility

NASA Technical Reports Server (NTRS)

Bobbitt, P. J.; Carter, J. E.

1977-01-01

Requirements for flow quality in the National Transonic Facility are explored. Viscous flow effects of concern to theoreticians are discussed. Experiments outlined for theory validation in the facility include validating high aspect ratio wing-body combination; low aspect ratio moderately swept wing; low aspect ratio highly swept wing; high lift systems on high aspect ration wings; Reynolds number scaling; dynamic shock- boundary layer interaction; and the effect of R and M on dynamic stall.

Test Report on Three- and Six-Component Measurements on a Series of Tapered Wings of Small Aspect Ratio

NASA Technical Reports Server (NTRS)

Lange; Wacke

1948-01-01

The investigations of the reports to 4 on wings of small aspect ratio are continued. The present report deals with the results of the three- and six-component measurements and the flow pictures of the triangular wing series with the aspect ratio Lambda = 3 to Lambda = 1.

Energy and economic trade offs for advanced technology subsonic aircraft

NASA Technical Reports Server (NTRS)

Maddalon, D. V.; Wagner, R. D.

1976-01-01

Changes in future aircraft technology which conserve energy are studied, along with the effect of these changes on economic performance. Among the new technologies considered are laminar-flow control, composite materials with and without laminar-flow control, and advanced airfoils. Aircraft design features studied include high-aspect-ratio wings, thickness ratio, and range. Engine technology is held constant at the JT9D level. It is concluded that wing aspect ratios of future aircraft are likely to significantly increase as a result of new technology and the push of higher fuel prices. Whereas current airplanes have been designed for AR = 7, supercritical technology and much higher fuel prices will drive aspect ratio to the AR = 9-10 range. Composite materials may raise aspect ratio to about 11-12 and practical laminar flow-control systems may further increase aspect ratio to 14 or more. Advanced technology provides significant reductions in aircraft take-off gross weight, energy consumption, and direct operating cost.

Isoprene photochemistry over the Amazon rainforest

DOE PAGES

Liu, Yingjun; Brito, Joel; Dorris, Matthew R.; ...

2016-05-31

Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO 2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK +more » MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4–0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. Also, a value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). In conclusion, this abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest.« less

Gravity Effects Observed In Partially Premixed Flames

NASA Technical Reports Server (NTRS)

Puri, Ishwar K.; Aggarwal, Suresh K.; Lock, Andrew J.; Gauguly, Ranjan; Hegde, Uday

2003-01-01

Partially premixed flames (PPFs) contain a rich premixed fuel air mixture in a pocket or stream, and, for complete combustion to occur, they require the transport of oxidizer from an appropriately oxidizer-rich (or fuel-lean) mixture that is present in another pocket or stream. Partial oxidation reactions occur in fuel-rich portions of the mixture and any remaining unburned fuel and/or intermediate species are consumed in the oxidizer-rich portions. Partial premixing, therefore, represents that condition when the equivalence ratio (phi) in one portion of the flowfield is greater than unity, and in another section its value is less than unity. In general, for combustion to occur efficiently, the global equivalence ratio is in the range fuel-lean to stoichiometric. These flames can be established by design by placing a fuel-rich mixture in contact with a fuel-lean mixture, but they also occur otherwise in many practical systems, which include nonpremixed lifted flames, turbulent nonpremixed combustion, spray flames, and unwanted fires. Other practical applications of PPFs are reported elsewhere. Although extensive experimental studies have been conducted on premixed and nonpremixed flames under microgravity, there is a absence of previous experimental work on burner stabilized PPFs in this regard. Previous numerical studies by our group employing a detailed numerical model showed gravity effects to be significant on the PPF structure. We report on the results of microgravity experiments conducted on two-dimensional (established on a Wolfhard-Parker slot burner) and axisymmetric flames (on a coannular burner) that were investigated in a self-contained multipurpose rig. Thermocouple and radiometer data were also used to characterize the thermal transport in the flame.

Isoprene photochemistry over the Amazon rainforest

PubMed Central

Liu, Yingjun; Brito, Joel; Dorris, Matthew R.; Rivera-Rios, Jean C.; Seco, Roger; Bates, Kelvin H.; Artaxo, Paulo; Duvoisin, Sergio; Keutsch, Frank N.; Kim, Saewung; Goldstein, Allen H.; Guenther, Alex B.; Manzi, Antonio O.; Souza, Rodrigo A. F.; Springston, Stephen R.; Watson, Thomas B.; McKinney, Karena A.

2016-01-01

Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK + MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4–0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). This abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest. PMID:27185928

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

Liu, Yingjun; Brito, Joel; Dorris, Matthew R.

Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO 2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK +more » MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4–0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. Also, a value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). In conclusion, this abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest.« less

Core compressor exit stage study. 1: Aerodynamic and mechanical design

NASA Technical Reports Server (NTRS)

Burdsall, E. A.; Canal, E., Jr.; Lyons, K. A.

1979-01-01

The effect of aspect ratio on the performance of core compressor exit stages was demonstrated using two three stage, highly loaded, core compressors. Aspect ratio was identified as having a strong influence on compressors endwall loss. Both compressors simulated the last three stages of an advanced eight stage core compressor and were designed with the same 0.915 hub/tip ratio, 4.30 kg/sec (9.47 1bm/sec) inlet corrected flow, and 167 m/sec (547 ft/sec) corrected mean wheel speed. The first compressor had an aspect ratio of 0.81 and an overall pressure ratio of 1.357 at a design adiabatic efficiency of 88.3% with an average diffusion factor or 0.529. The aspect ratio of the second compressor was 1.22 with an overall pressure ratio of 1.324 at a design adiabatic efficiency of 88.7% with an average diffusion factor of 0.491.

Manifesting the Quantum World

NASA Astrophysics Data System (ADS)

Mohrhoff, Ulrich

2014-06-01

In resisting attempts to explain the unity of a whole in terms of a multiplicity of interacting parts, quantum mechanics calls for an explanatory concept that proceeds in the opposite direction: from unity to multiplicity. Being part of the Scientific Image of the world, the theory concerns the process by which (the physical aspect of) what Sellars called the Manifest Image of the world comes into being. This process consists in the progressive differentiation of an intrinsically undifferentiated entity. By entering into reflexive spatial relations, this entity gives rise to (i) what looks like a multiplicity of relata if the reflexive quality of the relations is not taken into account, and (ii) what looks like a substantial expanse if the spatial quality of the relations is reified. If there is a distinctly quantum domain, it is a non-spatial and non-temporal dimension across which the transition from the unity of this entity to the multiplicity of the world takes place. Instead of being constituents of the physical world, subatomic particles, atoms, and molecules are instrumental in its manifestation. These conclusions are based on the following interpretive principle and its more direct consequences: whenever the calculation of probabilities calls for the addition of amplitudes, the distinctions we make between the alternatives lack objective reality. Applied to alternatives involving distinctions between regions of space, this principle implies that, owing to the indefiniteness of positions, the spatiotemporal differentiation of the physical world is incomplete: the existence of a real-valued spatiotemporal background is an unrealistic idealization. This guarantees the existence of observables whose values are real per se, as against "real by virtue of being indicated by the values of observables that are real per se." Applied to alternatives involving distinctions between things, it implies that, intrinsically, all fundamental particles are numerically identical and thus identifiable with the aforementioned undifferentiated entity.

Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio

PubMed Central

Kruyt, Jan W.; van Heijst, GertJan F.; Altshuler, Douglas L.; Lentink, David

2015-01-01

Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle of attack without stalling. Instead, they generate an attached vortex along the leading edge of the wing that elevates lift. Previous studies have demonstrated that this vortex and high lift can be reproduced by revolving the animal wing at the same angle of attack. How do flapping and revolving animal wings delay stall and reduce power? It has been hypothesized that stall delay derives from having a short radial distance between the shoulder joint and wing tip, measured in chord lengths. This non-dimensional measure of wing length represents the relative magnitude of inertial forces versus rotational accelerations operating in the boundary layer of revolving and flapping wings. Here we show for a suite of aspect ratios, which represent both animal and aircraft wings, that the attachment of the leading edge vortex on a revolving wing is determined by wing aspect ratio, defined with respect to the centre of revolution. At high angle of attack, the vortex remains attached when the local radius is shorter than four chord lengths and separates outboard on higher aspect ratio wings. This radial stall limit explains why revolving high aspect ratio wings (of helicopters) require less power compared with low aspect ratio wings (of hummingbirds) at low angle of attack and vice versa at high angle of attack. PMID:25788539

STS-88 Mission Commander Cabana looks at the mission payload Unity at pad

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Pad 39A, STS-88 Mission Commander Robert D. Cabana gets a close look at the Unity connecting module that is in the payload bay of the orbiter Endeavour. Cabana and the STS-88 crew arrived at KSC in the early morning hours of Nov. 30 for pre- launch preparations. The other crew members are Pilot Frederick W. 'Rick' Sturckow, Mission Specialist Nancy J. Currie, Mission Specialist James H. Newman and Mission Specialist Sergei Konstantinovich Krikalev, a Russian cosmonaut. The scheduled lift-off is at 3:56 a.m. on Dec. 3. Unity is the primary payload of the mission, which is the first U.S. launch for the International Space Station. The crew will be mating Unity with the Russian-built Zarya control module already in orbit. In addition to Unity, two small replacement electronics boxes are on board for possible repairs to Zarya batteries. Endeavour is expected to land at KSC at 10:17 p.m. on Monday, Dec. 14.

STS-88 Pilot Sturckow and Commander Cabana look over the payload Unity at pad

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Pad 39A, STS-88 Pilot Frederick W. 'Rick' Sturckow and Mission Commander Robert D. Cabana look over the Unity connecting module that is in the payload bay of the orbiter Endeavour. Cabana, Sturckow and the STS-88 crew arrived at KSC in the early morning hours of Nov. 30 for pre-launch preparations. The other crew members are Mission Specialist Nancy J. Currie, Mission Specialist James H. Newman and Mission Specialist Sergei Konstantinovich Krikalev, a Russian cosmonaut. The scheduled lift-off is at 3:56 a.m. on Dec. 3. Unity is the primary payload of the mission, which is the first U.S. launch for the International Space Station. The crew will be mating Unity with the Russian-built Zarya control module already in orbit. In addition to Unity, two small replacement electronics boxes are on board for possible repairs to Zarya batteries. Endeavour is expected to land at KSC at 10:17 p.m. on Monday, Dec. 14.

Quest for ultimate reality and meaning: a scientist's view

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

Gilbert, T.L.

The theme of unity and diversity is developed in four parts. The first part is an examination of the relationship between unity and diversity in terms of the concepts of scale and resolution, using an imaginary journey in a shrinking spaceship from the cosmos to quarks in order to present the concepts in concrete terms. The second part is an examination of the roles of different fields of scholarship - aesthetics and the humanities, ethics, religion, and science - in coping with diversity and in gleaning the unity hidden in diversity. The third part is an examination of a philosophicalmore » problem, closely related to unity and diversity, that can be expected to play a central role in later stages of the URAM program: the question of what we mean by the word true. The fourth part is a discussion of the concept of reality from the epistemological viewpoint of the sciences, and how unity and diversity enter into this concept.« less

Deep Reactive Ion Etching (DRIE) of High Aspect Ratio SiC Microstructures using a Time-Multiplexed Etch-Passivate Process

NASA Technical Reports Server (NTRS)

Evans, Laura J.; Beheim, Glenn M.

2006-01-01

High aspect ratio silicon carbide (SiC) microstructures are needed for microengines and other harsh environment micro-electro-mechanical systems (MEMS). Previously, deep reactive ion etching (DRIE) of low aspect ratio (AR less than or = 1) deep (greater than 100 micron) trenches in SiC has been reported. However, existing DRIE processes for SiC are not well-suited for definition of high aspect ratio features because such simple etch-only processes provide insufficient control over sidewall roughness and slope. Therefore, we have investigated the use of a time-multiplexed etch-passivate (TMEP) process, which alternates etching with polymer passivation of the etch sidewalls. An optimized TMEP process was used to etch high aspect ratio (AR greater than 5) deep (less than 100 micron) trenches in 6H-SiC. Power MEMS structures (micro turbine blades) in 6H-SiC were also fabricated.

Electrical Conductivity in Transparent Silver Nanowire Networks: Simulations and Experiments

NASA Astrophysics Data System (ADS)

Sherrott, Michelle; Mutiso, Rose; Rathmell, Aaron; Wiley, Benjamin; Winey, Karen

2012-02-01

We model and experimentally measure the electrical conductivity of two-dimensional networks containing finite, conductive cylinders with aspect ratio ranging from 33 to 333. We have previously used our simulations to explore the effects of cylinder orientation and aspect ratio in three-dimensional composites, and now extend the simulation to consider two-dimensional silver nanowire networks. Preliminary results suggest that increasing the aspect ratio and area fraction of these rods significantly decreases the sheet resistance of the film. For all simulated aspect ratios, this sheet resistance approaches a constant value for high area fractions of rods. This implies that regardless of aspect ratio, there is a limiting minimum sheet resistance that is characteristic of the properties of the nanowires. Experimental data from silver nanowire networks will be incorporated into the simulations to define the contact resistance and corroborate experimentally measured sheet resistances of transparent thin films.

Collisionless microtearing modes in hot tokamaks: Effect of trapped electrons

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

Swamy, Aditya K.; Ganesh, R., E-mail: ganesh@ipr.res.in; Brunner, S.

2015-07-15

Collisionless microtearing modes have recently been found linearly unstable in sharp temperature gradient regions of large aspect ratio tokamaks. The magnetic drift resonance of passing electrons has been found to be sufficient to destabilise these modes above a threshold plasma β. A global gyrokinetic study, including both passing electrons as well as trapped electrons, shows that the non-adiabatic contribution of the trapped electrons provides a resonant destabilization, especially at large toroidal mode numbers, for a given aspect ratio. The global 2D mode structures show important changes to the destabilising electrostatic potential. The β threshold for the onset of the instabilitymore » is found to be generally downshifted by the inclusion of trapped electrons. A scan in the aspect ratio of the tokamak configuration, from medium to large but finite values, clearly indicates a significant destabilizing contribution from trapped electrons at small aspect ratio, with a diminishing role at larger aspect ratios.« less

The Hydrodynamic Characteristics of Modified Rectangular Flat Plates Having Aspect Ratios of 1.00, 0.25, and 0.125 and Operating near a Free Water Surface

NASA Technical Reports Server (NTRS)

Wadlin, Kenneth L; Ramsen, John A; Vaughan, Victor L , Jr

1955-01-01

Report presents the results of an investigation conducted to determine the hydrodynamic forces and moments acting on modified rectangular flat plates with aspect ratios of 1.00, 0.25, and 0.125 mounted on a single strut and operating at several depths of submersion. A simple method has been developed by modification of Falkner's vortex-lattice theory which enables the prediction of the lift characteristics in unseparated flow at large depths. This method shows good agreement with experimental data from the present tests and with aerodynamic data at all angles investigated for aspect ratios of 1.00 and 0.25 and at angles up to 16 degrees for aspect ratio 0.125. Above 16 degrees for aspect ratio 0.125, the predicted lift proved too high.

A Study on Aspect Ratio of Heat Dissipation Fin for the Heat Dissipation Performance of Ultra Constant Discharge Lamp

NASA Astrophysics Data System (ADS)

Ko, Dong Guk; Cong Ge, Jun; Im, Ik Tae; Choi, Nag Jung; Kim, Min Soo

2018-01-01

In this study, we analyzed the heat dissipation performance of UCD lamp ballast fin with various aspect ratios. The minimum grid size was 0.02 mm and the number of grid was approximately 11,000. In order to determine the influence of the aspect ratio on the heat dissipation performance of UCD lamp ballast fin, the heat transfer area of the fin was kept constant at 4 mm2. The aspect ratios of the fin were 2 mm: 2 mm (basic model), 1.5 mm: 2.7 mm and 2.7 mm: 1.5 mm, respectively. The heat flux and heat flux time at fin were kept constant at 1×105 W/m2 and 10 seconds, respectively. The heat dissipation performance by the fin was the best at an aspect ratio of 1.5 mm: 2.7 mm.

Anisotropic Structure of Rotating Homogeneous Turbulence at High Reynolds Numbers

NASA Technical Reports Server (NTRS)

Cambon, Claude; Mansour, Nagi N.; Squires, Kyle D.; Rai, Man Mohan (Technical Monitor)

1995-01-01

Large eddy simulation is used to investigate the development of anisotropies and the evolution towards a quasi two-dimensional state in rotating homogeneous turbulence at high Reynolds number. The present study demonstrates the existence of two transitions in the development of anisotropy. The first transition marks the onset of anisotropy and occurs when a macro-Rossby number (based on a longitudinal integral lengthscale) has decreased to near unity while the second transition occurs when a micro-Rossby number (defined in this work as the ratio of the rms fluctuating vorticity to background vorticity) has decreased to unity. The anisotropy marked by the first transition corresponds to a reduction in dimensionality while the second transition corresponds to a polarization of the flow, i.e., relative dominance of the velocity components in the plane normal to the rotation axis. Polarization is reflected by emergence of anisotropy measures based on the two-dimensional component of the turbulence. Investigation of the vorticity structure shows that the second transition is also characterized by an increasing tendency for alignment between the fluctuating vorticity vector and the background angular velocity vector with a preference for corrotative vorticity.

Influence of Germanium source on dopingless tunnel-FET for improved analog/RF performance

NASA Astrophysics Data System (ADS)

Cecil, Kanchan; Singh, Jawar

2017-01-01

Dopingless (DL) and junctionless devices have attracted attention due to their simplified fabrication process and low thermal budget requirements. Therefore, in this work, we investigated the influence of low band gap Germanium (Ge) instead of Silicon (Si) as a "Source region" material in dopingless (DL) tunnel field-effect transistor (DLTFET). We observed that the Ge source DLTFET delivers much better performance in comparison to Si DLTFET under various analog/RF figure of merits (FOMs), such as transconductance (gm), transconductance generation factor (TGF) (gm /Id), output conductance (gd), output resistance (RO), intrinsic gain (gmRO), intrinsic gate delay (τ) and RF FOMs, like unity gain frequency (fT), gain bandwidth product (GBW) along with various gate capacitances. These parameters were extracted using 2D TCAD device simulations through small signal ac analysis. Higher ION /IOFF ratio (1014) of Ge source DLTFET can reduce the dynamic as well as static power in digital circuits, while higher transconductance generation factor (gm /Id) ∼ 2287 V-1 can lower the bias power of an amplifier. Similarly, enhanced RF FOMs i.e unity gain frequency (fT) and gain bandwidth product (GBW) in Gigahertz range projects the proposed device preference for RF circuits.

Separation of Hydrogen from Carbon Dioxide through Porous Ceramics

PubMed Central

Shimonosono, Taro; Imada, Hikari; Maeda, Hikaru; Hirata, Yoshihiro

2016-01-01

The gas permeability of α-alumina, yttria-stabilized zirconia (YSZ), and silicon carbide porous ceramics toward H2, CO2, and H2–CO2 mixtures were investigated at room temperature. The permeation of H2 and CO2 single gases occurred above a critical pressure gradient, which was smaller for H2 gas than for CO2 gas. When the Knudsen number (λ/r ratio, λ: molecular mean free path, r: pore radius) of a single gas was larger than unity, Knudsen flow became the dominant gas transportation process. The H2 fraction for the mixed gas of (20%–80%) H2–(80%–20%) CO2 through porous Al2O3, YSZ, and SiC approached unity with decreasing pressure gradient. The high fraction of H2 gas was closely related to the difference in the critical pressure gradient values of H2 and CO2 single gas, the inlet mixed gas composition, and the gas flow mechanism of the mixed gas. Moisture in the atmosphere adsorbed easily on the porous ceramics and affected the critical pressure gradient, leading to the increased selectivity of H2 gas. PMID:28774051

Newman and Cabana in the Node 1/Unity module

NASA Image and Video Library

1998-12-11

STS088-357-016 (4-15 Dec. 1998) --- Astronauts James H. Newman (left), mission specialist, and Robert D. Cabana, mission commander, look over checklists as they prepare to continue work in the U.S.-built Unity connecting module in Earth orbit. The STS-88 crew went on to spend eleven days in space preparing Unity and the attached Russian-built Zarya module for their International Space Station (ISS) roles.

View in the Node 1/Unity module after docking

NASA Image and Video Library

1998-12-10

S88-E-5112 (12-10-98)) --- Astronaut Jerry L. Ross, mission specialist, packs a bag of tools and equipment in the hatchway of the Unity connecting module. Ross and his crewmates were installing hand rails and other equipment and performing various tasks to ready the Unity and Zarya for their ISS roles. The photo was taken with an electronic still camera at 20:26:02 GMT, Dec. 10.

Sturckow in Node 1/Unity module with power tool

NASA Image and Video Library

1998-12-11

S88-E-5126 (12-11-98) --- Astronaut Frederick W. Sturckow, pilot, is pictured with a power tool near the hatchway between Unity and a pressurized mating adapter (PMA). Members of the STS-88 crew used this type tool and others to attach handrails and accessories and perform other tasks on Unity. The photo was taken with an electronic still camera (ESC) at 01:09:40 GMT, Dec. 11.

ODS and RMS arm in position to grapple Node 1/Unity module

NASA Image and Video Library

1998-12-05

STS088-361-021 (4-15 Dec. 1998) --- The Canadian-built Remote Manipulator System (RMS) arm is about to grapple the Node 1 or Unity Module for mating to the Space Shuttle Endeavour. The move marked the first of many steps that allowed the United States-built Unity Module to be docked with the Russian-built FGB or Zarya Module later in the mission.

The philosophy of 'unity of knowledge and action' in interventional neuroradiology teaching.

PubMed

Lv, Xianli; Wu, Zhongxue

2018-06-01

Despite the continuing emphasis on the importance of clinical skills, these skills do not appear to be improving and may actually be declining. The 'unity of knowledge and action' is a medicine directed precisely at this disease. The 'unity of knowledge and action' helps to learn from failure and successes, learn from mistakes of predecessors and institute a behaviour that prevents repetition of these mistakes.

Tactical Implications for Peacemaking in Ethnic Conflict

DTIC Science & Technology

1993-02-04

means to achieve unity of effort; but unity of effort is achievable without unity of command. Second, units exhibited great versatility. Third , the Army...reviews the post-Persian Gulf War operations, emphasizing OPC. The third section analyzes some tactical lessons learned from OPC. This section uses the...commitments have not decreased. Third , the nation and the Army cannot afford a standing force dedicated to every type of contingency. Finally

2D and 3D virtual interactive laboratories of physics on Unity platform

NASA Astrophysics Data System (ADS)

González, J. D.; Escobar, J. H.; Sánchez, H.; De la Hoz, J.; Beltrán, J. R.

2017-12-01

Using the cross-platform game engine Unity, we develop virtual laboratories for PC, consoles, mobile devices and website as an innovative tool to study physics. There is extensive uptake of ICT in the teaching of science and its impact on the learning, and considering the limited availability of laboratories for physics teaching and the difficulties this causes in the learning of school students, we design the virtual laboratories to enhance studentâĂŹs knowledge of concepts in physics. To achieve this goal, we use Unity due to provide support bump mapping, reflection mapping, parallax mapping, dynamics shadows using shadows maps, full-screen post-processing effects and render-to-texture. Unity can use the best variant for the current video hardware and, if none are compatible, to use an alternative shader that may sacrifice features for performance. The control over delivery to mobile devices, web browsers, consoles and desktops is the main reason Unity is the best option among the same kind cross-platform. Supported platforms include Android, Apple TV, Linux, iOS, Nintendo 3DS line, macOS, PlayStation 4, Windows Phone 8, Wii but also an asset server and Nvidia’s PhysX physics engine which is the most relevant tool on Unity for our PhysLab.

An Experimental Study on the Edgewise Compressive Failure of Paper Honeycomb Sandwich Panels with Respect to Various Aspect Ratios

NASA Astrophysics Data System (ADS)

Samad, W. A.; Warsame, A. A.; Khan, A.

2018-04-01

The present work investigates the edgewise compression failure for honeycomb paperboards. Various panels are tested under a fixed loading rate with varying aspect ratios. The influence of the varying properties aspect ratio on yield strength is recorded. The experimental results indicate that the honeycomb paperboards are subject a decrease in yield strength with an increase in aspect ratio towards more slender bodies. Buckling was not observed in any of the tested specimens. All experiments are conducted under the general framework of ASTM C364/C364M -16 with a few noted changes.

Transport phenomena during vapor growth of optoelectronic material - A mercurous chloride system

NASA Technical Reports Server (NTRS)

Singh, N. B.

1990-01-01

Crystal growth velocity was measured in a mercurous chloride system in a two-zone transparent furnace as a function of the Rayleigh number by varying a/L, where a is the radius of the growth tube and L is the transport length. Growth velocity data showed different trends at low and high aspect ratio, a result that does not support the velocity-aspect ratio trend predicted by theories. The system cannot be scaled on the basis of measurements done at a low aspect ratio. Some change in fluid flow behavior occurs in the growth tube as the aspect ratio increases.

Multiscale Pores in TBCs for Lower Thermal Conductivity

NASA Astrophysics Data System (ADS)

Zhang, Wei-Wei; Li, Guang-Rong; Zhang, Qiang; Yang, Guan-Jun

2017-08-01

The morphology and pattern (including orientation and aspect ratio) of pores in thermal barrier coatings (TBCs) significantly affect their thermal insulation performance. In this work, finite element analysis was used to comprehensively understand the thermal insulation effect of pores and correlate the effective thermal conductivity with the structure. The results indicated that intersplat pores, and in particular their aspect ratio, dominantly affect the heat transfer in the top coat. The effective thermal conductivity decreased as a function of aspect ratio, since a larger aspect ratio often corresponds to a greater proportion of effective length of the pores. However, in conventional plasma-sprayed TBCs, intersplat pores often fail to maximize thermal insulation due to their distinct lower aspect ratios. Therefore, considering this effect of aspect ratio, a new structure design with multiscale pores is proposed and a corresponding structural model developed to correlate the thermal properties with this pore-rich structure. The predictions of the model are well consistent with experimental data. This study provides comprehensive understanding of the effect of pores on the thermal insulation performance, shedding light on the possibility of structural tailoring to obtain advanced TBCs with lower thermal conductivity.

Chemical Characterization and Source Apportionment of Indoor and Outdoor Fine Particulate Matter (PM2.5) in Retirement Communities of the Los Angeles Basin

PubMed Central

Hasheminassab, Sina; Daher, Nancy; Shafer, Martin M.; Schauer, James J.; Delfino, Ralph J.; Sioutas, Constantinos

2014-01-01

Concurrent indoor and outdoor measurements of fine particulate matter (PM2.5) were conducted at three retirement homes in the Los Angeles Basin during two separate phases (cold and warm) between 2005 and 2006. Indoor-to-outdoor relationships of PM2.5 chemical constituents were determined and sources of indoor and outdoor PM2.5 were evaluated using a molecular marker-based chemical mass balance (MM-CMB) model. Indoor levels of elemental carbon (EC) along with metals and trace elements were found to be significantly affected by outdoor sources. EC, in particular, displayed very high indoor-to-outdoor (I/O) mass ratios accompanied by strong I/O correlations, illustrating the significant impact of outdoor sources on indoor levels of EC. Similarly, indoor levels of polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes were strongly correlated with their outdoor components and displayed I/O ratios close to unity. On the other hand, concentrations of n-alkanes and organic acids inside the retirement communities were dominated by indoor sources (e.g. food cooking and consumer products), as indicated by their I/O ratios, which exceeded unity. Source apportionment results revealed that vehicular emissions were the major contributor to both indoor and outdoor PM2.5, accounting for 39 and 46% of total mass, respectively. Moreover, the contribution of vehicular sources to indoor levels was generally comparable to its corresponding outdoor estimate. Other water-insoluble organic matter (other WIOM), which accounts for emissions from uncharacterized primary biogenic sources, displayed a wider range of contributions, varying from 2 to 73% of PM2.5, across all sites and phases of the study. Lastly, higher indoor than outdoor contribution of other water-soluble organic matter (other WSOM) was evident at some of the sites, suggesting the production of secondary aerosols as well as direct emissions from primary sources (including cleaning or other consumer products) at the indoor environments. PMID:24880542

Fabrication of high aspect ratio nanogrid transparent electrodes via capillary assembly of Ag nanoparticles

NASA Astrophysics Data System (ADS)

Kang, Juhoon; Park, Chang-Goo; Lee, Su-Han; Cho, Changsoon; Choi, Dae-Geun; Lee, Jung-Yong

2016-05-01

In this report, we describe the fabrication of periodic Ag nanogrid electrodes by capillary assembly of silver nanoparticles (AgNPs) along patterned nanogrid templates. By assembling the AgNPs into these high-aspect-ratio nanogrid patterns, we can obtain high-aspect-ratio nanogratings, which can overcome the inherent trade-off between the optical transmittance and the sheet resistance of transparent electrodes. The junction resistance between the AgNPs is effectively reduced by photochemical welding and post-annealing. The fabricated high-aspect-ratio nanogrid structure with a line width of 150 nm and a height of 450 nm has a sheet resistance of 15.2 Ω sq-1 and an optical transmittance of 85.4%.In this report, we describe the fabrication of periodic Ag nanogrid electrodes by capillary assembly of silver nanoparticles (AgNPs) along patterned nanogrid templates. By assembling the AgNPs into these high-aspect-ratio nanogrid patterns, we can obtain high-aspect-ratio nanogratings, which can overcome the inherent trade-off between the optical transmittance and the sheet resistance of transparent electrodes. The junction resistance between the AgNPs is effectively reduced by photochemical welding and post-annealing. The fabricated high-aspect-ratio nanogrid structure with a line width of 150 nm and a height of 450 nm has a sheet resistance of 15.2 Ω sq-1 and an optical transmittance of 85.4%. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01896c

Experimental study of low aspect ratio compressor blading

NASA Technical Reports Server (NTRS)

Reid, L.; Moore, R. D.

1979-01-01

The effects of low aspect ratio blading on aerodynamic performance were examined. Four individual transonic compressor stages, representative of the inlet stage of an advanced high pressure ratio core compressor, are discussed. The flow phenomena for the four stages are investigated. Comparisons of blade element parameters are presented for the two different aspect ratio configurations. Blade loading levels are compared for the near stall conditions and comparisons are made of loss and diffusion factors over the operating range of incidence angles.

U-Sries Disequilibra in Soils, Pena Blanca Natural Analog, Chihuahua, Mexico

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

D. French; E. Anthony; P. Goodell

2006-03-16

The Nopal I uranium deposit located in the Sierra Pena Blanca, Mexico. The deposit was mined in the early 1980s, and ore was stockpiled close by. This stockpile area was cleared and is now referred to as the Prior High Grade Stockpile (PHGS). Some of the high-grade boulders from the site rolled downhill when it was cleared in the 1990s. For this study soil samples were collected from the alluvium surrounding and underlying one of these boulders. A bulk sample of the boulder was also collected. Because the Prior High Grade Stockpile had no ore prior to the 1980s amore » maximum residence time for the boulder is about 25 years, this also means that the soil was at background as well. The purpose of this study is to characterize the transport of uranium series radionuclides from ore to the soil. Transport is characterized by determining the activities of individual radionuclides and daughter to parent ratios. Isotopes of the uranium series decay chain detected include {sup 210}Pb, {sup 234}U, {sup 230}Th, {sup 226}Ra, {sup 214}Pb, and {sup 214}Bi. Peak areas for each isotope are determined using gamma-ray spectroscopy with a Canberra Ge (Li) detector and GENIE 2000 software. The boulder sample is close to secular equilibrium when compared to the standard BL-5 (Beaver Lodge Uraninite from Canada). Results for the soils, however, indicate that some daughter/parent pairs are in secular disequilibrium. These daughter/parent (D/P) ratios include {sup 230}Th/{sup 234}U, which is greater than unity, {sup 226}Ra/{sup 230}Th, which is also greater than unity, and {sup 210}Pb/{sup 214}Bi, which is less than unity. The gamma-ray spectrum for organic material lacks {sup 230}Th peaks, but contains {sup 234}U and {sup 226}Ra, indicating that plants preferentially incorporate {sup 226}Ra. Our results, combined with previous studies require multistage history of mobilization of the uranium series radionuclides. Earlier studies at the ore zone could limit the time span for mobilization only to a few thousand years. The contribution of this study is that the short residence time of the ore at the Prior High Grade Stockpile requires a time span for mobilization of 20-30 years.« less

A Design for Cross-Cultural Unity: A Partnership of Church and Community College. Perspectives on the Church and the Community College, Paper Number Seventeen.

ERIC Educational Resources Information Center

Shinto, William

Although the integration movement of the 1960's and the demands for cultural pluralism in the 1970's addressed the issues of racial unity and minority civil rights, a new consciousness of cross-cultural unity among all ethnic groups must be achieved if racial tension is ever to be abated. Accordingly, cultural differences must not be viewed as the…

Currie and Ross in the Node 1/Unity module

NASA Image and Video Library

1998-12-11

STS088-357-020 (4-15 Dec. 1998) --- Astronauts Jerry L. Ross and Nancy J. Currie, both mission specialists, check procedures list prior to performing a variety of tasks in the United States-built Node 1 or Unity Module. The hatchway in upper left corner accesses the Russian-built FGB or Zarya Module, which had earlier been retrieved with the aid of the Canadian-built Remote Manipulator System (RMS) and linked with Unity.

Unity connecting module viewed from above in the Space Station Processing Facility

NASA Technical Reports Server (NTRS)

1998-01-01

The Unity connecting module is viewed from above while it awaits processing in the Space Station Processing Facility (SSPF). On the side can be seen the connecting hatch. The Unity, scheduled to be launched on STS-88 in December 1998, will be mated to the Russian-built Zarya control module which will already be in orbit. STS-88 will be the first Space Shuttle launch for the International Space Station.

["The grandest hero who has ever lived": an unpublished letter written by Florence Nightingale about Garibaldi].

PubMed

Festini, Filippo; Giusti, Francesca

2012-01-01

In the year of the 150th anniversary of the Unity of Italy, Italian nurses cannot forget that Florence Nightingale herself, founder of modern Nursing , was a fervid support of the Risorgimento and of Italian unity. An unpublished letter, signed by her and conserved in the State archives of Pistoia, illustrates her feelings about the process of unity under way in the country where she was born.

The Unity Council at 40: a pioneering community development and service organization (1967-2007).

PubMed

Orozco, Gabriel; Schwartz, Sara L; Austin, Michael J

2011-01-01

The Spanish Speaking Unity Council (Unity Council) is a community development nonprofit organization that was established in 1964, during the civil rights movement, by a group of community members who wanted to ensure the political representation of the Latino community. Over its 45-year history, the Unity Council has grown into a $12 million community development organization that delivers a range of programming, including social services and employment training as well as facilitating the development and support of local businesses, low-income housing, and neighborhood improvement activities. The history of the agency presents the multiple challenges and rewards associated with development in an underserved community and an example of the important role that leadership plays in the growth of a nonprofit.

The threshold signal:noise ratio in the perception of fragmented figures.

PubMed

Merkul'ev, A V; Pronin, S V; Semenov, L A; Foreman, N; Chikhman, V N; Shelepin, Yu E

2006-01-01

Perception thresholds were measured for fragmented outline figures (the Gollin test). A new approach to the question of the perception of incomplete images was developed. In this approach, figure fragmentation consisted of masking with multiplicative texture-like noise--this interference was termed "invisible" masking. The first series of studies established that the "similarity" between the amplitude-frequency spectra of test figures and "invisible" masks, expressed as a linear correlation coefficient, had significant effects on the recognition thresholds of these figures. The second series of experiments showed that progressing formation of the figures was accompanied by increases in the correlation between their spatial-frequency characteristics and the corresponding characteristics of the incomplete figure, while the correlation with the "invisible" mask decreased. It is suggested that the ratio of the correlation coefficients, characterizing the "similarity" of the fragmented figure with the intact figure and the "invisible" mask, corresponds to the signal:noise ratio. The psychophysical recognition threshold for figures for naive subjects not familiar with the test image alphabet was reached after the particular level of fragmentation at which this ratio was unity.

U-isotopes and (226)Ra as tracers of hydrogeochemical processes in carbonated karst aquifers from arid areas.

PubMed

Guerrero, José Luis; Vallejos, Ángela; Cerón, Juan Carlos; Sánchez-Martos, Francisco; Pulido-Bosch, Antonio; Bolívar, Juan Pedro

2016-07-01

Sierra de Gádor is a karst macrosystem with a highly complex geometry, located in southeastern Spain. In this arid environment, the main economic activities, agriculture and tourism, are supported by water resources from the Sierra de Gádor aquifer system. The aim of this work was to study the levels and behaviour of some of the most significant natural radionuclides in order to improve the knowledge of the hydrogeochemical processes involved in this groundwater system. For this study, 28 groundwater and 7 surface water samples were collected, and the activity concentrations of the natural U-isotopes ((238)U, (235)U and (234)U) and (226)Ra by alpha spectrometry were determined. The activity concentration of (238)U presented a large variation from around 1.1 to 65 mBq L(-1). Elevated groundwater U concentrations were the result of oxidising conditions that likely promoted U dissolution. The PHREEQC modelling code showed that dissolved U mainly existed as uranyl carbonate complexes. The (234)U/(238)U activity ratios were higher than unity for all samples (1.1-3.8). Additionally, these ratios were in greater disequilibrium in groundwater than surface water samples, the likely result of greater water-rock contact time. (226)Ra presented a wide range of activity concentrations, (0.8 up to about 4 × 10(2) mBq L(-1)); greatest concentrations were detected in the thermal area of Alhama. Most of the samples showed (226)Ra/(234)U activity ratios lower than unity (median = 0.3), likely the result of the greater mobility of U than Ra in the aquifer system. The natural U-isotopes concentrations were strongly correlated with dissolution of sulphate evaporites (mainly gypsum). (226)Ra had a more complex behaviour, showing a strong correlation with water salinity, which was particularly evident in locations where thermal anomalies were detected. The most saline samples showed the lowest (234)U/(238)U activity ratios, probably due to fast uniform bulk mineral dissolution, which would minimize the impact of solubility-controlled fractionation processes. Furthermore, the high bulk dissolution rates promoted greater groundwater (226)Ra/(234)U ratios because the Ra has a comparatively much greater mobility than U in saline conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Changes in the frequency distribution of energy deposited in short pathlengths as a function of energy degradation of the primary beam.

NASA Technical Reports Server (NTRS)

Baily, N. A.; Steigerwalt, J. E.; Hilbert, J. W.

1972-01-01

The frequency distributions of event size in the deposition of energy over small pathlengths have been measured after penetration of 44.3 MeV protons through various thicknesses of tissue-equivalent material. Results show that particle energy straggling of an initially monoenergetic proton beam after passage through an absorber causes the frequency distributions of energy deposited in short pathlengths of low atomic number materials to remain broad. In all cases investigated, the ratio of the most probable to the average energy losses has been significantly less than unity.

On the η and η ' photoproduction beam asymmetry at high energies

DOE PAGES

Mathieu, V.; Nys, J.; Fernandez-Ramirez, C.; ...

2017-09-29

Here, we show that, in the Regge limit, beam asymmetries inmore » $$\\eta$$ and $$\\eta'$$ photoproduction are sensitive to hidden strangeness components. Under reasonable assumptions about the couplings we estimate the contribution of the $$\\phi$$ Regge pole, which is expected to be the dominant hidden strangeness contribution. The ratio of the asymmetries in $$\\eta'$$ and $$\\eta$$ production is estimated to be close to unity in the forward region $$0 < -t/\\text{GeV}^2 \\leq 1$$ at the photon energy $$E_\\text{lab} = 9$$~GeV, relevant for the upcoming measurements at Jefferson Lab.« less

Hydrides of intermetallic compounds with a H/M ratio greater than unity obtained at high hydrogen pressures

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

Semenenko, K.N.; Klyamkin, S.N.

1993-11-01

Novel hydride phases with H/M > 1 based on Zr{sub 2}Pd, Hf{sub 2}Pd, and Hf{sub 2}Cu (structures of the MoSi{sub 2} type) have been synthesized at high H{sub 2} pressures. The X-ray diffraction investigations of the resulting hydrides have been carried out. Some factors determining the maximum hydrogen content in the hydrides of intermetallic compounds are discussed. A model structure of the hydrides obtained is proposed, which assumes the possibility of direct H-H interactions when the interatomic distances are less than 1 {angstrom}.

METHOD OF ISOTOPE CONCENTRATION

DOEpatents

Taylor, T.I.; Spindel, W.

1960-02-01

A method of concentrating N/sup 15/ in a liquid is described. Gaseous nitric oxide and at least one liquid selected from the group consisting of the aqueous oxyacids and oxides of nitrogen, wherein the atomic ratio of oxygen to nitrogen is greater than unity, are brought into intimate contact to cause an enrichment of the liquid and a depletion of the gas in N/sup 15/. The liquid is, thereafter, reacted with sulfur dioxide to produce a gas contuining nitric oxide. The gas contuining nitric oxide is then continuously passed in countercurrent contact with the liquid to cause further enrichment of the liquid.

Generalization of low pressure, gas-liquid, metastable sound speed to high pressures

NASA Technical Reports Server (NTRS)

Bursik, J. W.; Hall, R. M.

1981-01-01

A theory is developed for isentropic metastable sound propagation in high pressure gas-liquid mixtures. Without simplification, it also correctly predicts the minimum speed for low pressure air-water measurements where other authors are forced to postulate isothermal propagation. This is accomplished by a mixture heat capacity ratio which automatically adjusts from its single phase values to approximately the isothermal value of unity needed for the minimum speed. Computations are made for the pure components parahydrogen and nitrogen, with emphasis on the latter. With simplifying assumptions, the theory reduces to a well known approximate formula limited to low pressure.

Vortex motion in axisymmetric piston-cylinder configurations

NASA Technical Reports Server (NTRS)

Shih, T. I. P.; Smith, G. E.; Springer, G. S.

1982-01-01

By using the Beam and Warming implicit-factored method of solution of the Navier-Stokes equations, velocities were calculated inside axisymmetric piston cylinder configurations during the intake and compression strokes. Results are presented in graphical form which show the formation, growth and breakup of those vortices which form during the intake stroke by the jet issuing from the valve. It is shown that at bore-to-stroke ratio of less than unity, the vortices may breakup during the intake stroke. It is also shown that vortices which do not breakup during the intake stroke coalesce during the compression stroke.

Monte Carlo calculated correction factors for diodes and ion chambers in small photon fields.

PubMed

Czarnecki, D; Zink, K

2013-04-21

The application of small photon fields in modern radiotherapy requires the determination of total scatter factors Scp or field factors Ω(f(clin), f(msr))(Q(clin), Q(msr)) with high precision. Both quantities require the knowledge of the field-size-dependent and detector-dependent correction factor k(f(clin), f(msr))(Q(clin), Q(msr)). The aim of this study is the determination of the correction factor k(f(clin), f(msr))(Q(clin), Q(msr)) for different types of detectors in a clinical 6 MV photon beam of a Siemens KD linear accelerator. The EGSnrc Monte Carlo code was used to calculate the dose to water and the dose to different detectors to determine the field factor as well as the mentioned correction factor for different small square field sizes. Besides this, the mean water to air stopping power ratio as well as the ratio of the mean energy absorption coefficients for the relevant materials was calculated for different small field sizes. As the beam source, a Monte Carlo based model of a Siemens KD linear accelerator was used. The results show that in the case of ionization chambers the detector volume has the largest impact on the correction factor k(f(clin), f(msr))(Q(clin), Q(msr)); this perturbation may contribute up to 50% to the correction factor. Field-dependent changes in stopping-power ratios are negligible. The magnitude of k(f(clin), f(msr))(Q(clin), Q(msr)) is of the order of 1.2 at a field size of 1 × 1 cm(2) for the large volume ion chamber PTW31010 and is still in the range of 1.05-1.07 for the PinPoint chambers PTW31014 and PTW31016. For the diode detectors included in this study (PTW60016, PTW 60017), the correction factor deviates no more than 2% from unity in field sizes between 10 × 10 and 1 × 1 cm(2), but below this field size there is a steep decrease of k(f(clin), f(msr))(Q(clin), Q(msr)) below unity, i.e. a strong overestimation of dose. Besides the field size and detector dependence, the results reveal a clear dependence of the correction factor on the accelerator geometry for field sizes below 1 × 1 cm(2), i.e. on the beam spot size of the primary electrons hitting the target. This effect is especially pronounced for the ionization chambers. In conclusion, comparing all detectors, the unshielded diode PTW60017 is highly recommended for small field dosimetry, since its correction factor k(f(clin), f(msr))(Q(clin), Q(msr)) is closest to unity in small fields and mainly independent of the electron beam spot size.

Acicular photomultiplier photocathode structure

DOEpatents

Craig, Richard A.; Bliss, Mary

2003-09-30

A method and apparatus for increasing the quantum efficiency of a photomultiplier tube by providing a photocathode with an increased surface-to-volume ratio. The photocathode includes a transparent substrate, upon one major side of which is formed one or more large aspect-ratio structures, such as needles, cones, fibers, prisms, or pyramids. The large aspect-ratio structures are at least partially composed of a photoelectron emitting material, i.e., a material that emits a photoelectron upon absorption of an optical photon. The large aspect-ratio structures may be substantially composed of the photoelectron emitting material (i.e., formed as such upon the surface of a relatively flat substrate) or be only partially composed of a photoelectron emitting material (i.e., the photoelectron emitting material is coated over large aspect-ratio structures formed from the substrate material itself.) The large aspect-ratio nature of the photocathode surface allows for an effective increase in the thickness of the photocathode relative the absorption of optical photons, thereby increasing the absorption rate of incident photons, without substantially increasing the effective thickness of the photocathode relative the escape incidence of the photoelectrons.

Visualization of Secondary Flow Development in High Aspect Ratio Channels with Curvature

NASA Technical Reports Server (NTRS)

Meyer, Michael L.; Giuliani, James E.

1994-01-01

The results of an experimental project to visually examine the secondary flow structure that develops in curved, high aspect-ratio rectangular channels are presented. The results provide insight into the fluid dynamics within high aspect ratio channels. A water flow test rig constructed out of plexiglass, with an adjustable aspect ratio, was used for these experiments. Results were obtained for a channel geometry with a hydraulic diameter of 10.6 mm (0.417 in.), an aspect ratio of 5.0, and a hydraulic radius to curvature radius ratio of 0.0417. Flow conditions were varied to achieve Reynolds numbers up to 5,100. A new particle imaging velocimetry technique was developed which could resolve velocity information from particles entering and leaving the field of view. Time averaged secondary flow velocity vectors, obtained using this velocimetry technique, are presented for 30 degrees, 60 degrees, and 90 degrees into a 180 degrees bend and at a Reynolds number of 5,100. The secondary flow results suggest the coexistence of both the classical curvature induced vortex pair flow structure and the eddies seen in straight turbulent channel flow.

Sedimentation of a sphere in a fluid channel

NASA Astrophysics Data System (ADS)

Pitois, Olivier; Fritz, Christelle; Pasol, Laurentiu; Vignes-Adler, Michèle

2009-10-01

We studied both experimentally and numerically the sedimentation velocity of small solid particles through liquid channels merging at the intersection of three soap films. The wall mobility induces a nontrivial behavior for the particle drag coefficient, providing particular transport properties that are not observed for channels with rigid walls. It is shown that for sufficiently small particles, slow and fast motions are observed for the particle along the channel, depending on the particle position within the channel cross section and the sphere/channel size ratio. The velocity corresponding to fast motions can be as high as twice the Stokes velocity in an unbounded fluid. Moreover, the fast motions are not observed anymore when the size ratio exceeds a critical value, which has been found to be approximately equal to 0.5. As another major difference with the solid wall channel, the sphere velocity does not vanish when the size ratio reaches unity. Instead, the smallest value is found to be 1/4 of the Stokes velocity.

Estimating weak ratiometric signals in imaging data. I. Dual-channel data.

PubMed

Broder, Josef; Majumder, Anirban; Porter, Erika; Srinivasamoorthy, Ganesh; Keith, Charles; Lauderdale, James; Sornborger, Andrew

2007-09-01

Ratiometric fluorescent indicators are becoming increasingly prevalent in many areas of biology. They are used for making quantitative measurements of intracellular free calcium both in vitro and in vivo, as well as measuring membrane potentials, pH, and other important physiological variables of interest to researchers in many subfields. Often, functional changes in the fluorescent yield of ratiometric indicators are small, and the signal-to-noise ratio (SNR) is of order unity or less. In particular, variability in the denominator of the ratio can lead to very poor ratio estimates. We present a statistical optimization method for objectively detecting and estimating ratiometric signals in dual-wavelength measurements of fluorescent, ratiometric indicators that improves on standard methods. With the use of an appropriate statistical model for ratiometric signals and by taking the pixel-pixel covariance of an imaging dataset into account, we are able to extract user-independent spatiotemporal information that retains high resolution in both space and time.

The unity assumption facilitates cross-modal binding of musical, non-speech stimuli: The role of spectral and amplitude envelope cues.

PubMed

Chuen, Lorraine; Schutz, Michael

2016-07-01

An observer's inference that multimodal signals originate from a common underlying source facilitates cross-modal binding. This 'unity assumption' causes asynchronous auditory and visual speech streams to seem simultaneous (Vatakis & Spence, Perception & Psychophysics, 69(5), 744-756, 2007). Subsequent tests of non-speech stimuli such as musical and impact events found no evidence for the unity assumption, suggesting the effect is speech-specific (Vatakis & Spence, Acta Psychologica, 127(1), 12-23, 2008). However, the role of amplitude envelope (the changes in energy of a sound over time) was not previously appreciated within this paradigm. Here, we explore whether previous findings suggesting speech-specificity of the unity assumption were confounded by similarities in the amplitude envelopes of the contrasted auditory stimuli. Experiment 1 used natural events with clearly differentiated envelopes: single notes played on either a cello (bowing motion) or marimba (striking motion). Participants performed an un-speeded temporal order judgments task; viewing audio-visually matched (e.g., marimba auditory with marimba video) and mismatched (e.g., cello auditory with marimba video) versions of stimuli at various stimulus onset asynchronies, and were required to indicate which modality was presented first. As predicted, participants were less sensitive to temporal order in matched conditions, demonstrating that the unity assumption can facilitate the perception of synchrony outside of speech stimuli. Results from Experiments 2 and 3 revealed that when spectral information was removed from the original auditory stimuli, amplitude envelope alone could not facilitate the influence of audiovisual unity. We propose that both amplitude envelope and spectral acoustic cues affect the percept of audiovisual unity, working in concert to help an observer determine when to integrate across modalities.

Korean Affairs Report, Kulloja, No. 10, October 1984.

DTIC Science & Technology

1985-06-04

places the respected and beloved Comrade Kim Il-song as the center of leadership and as the center of unity and solidarity. At the inception of...Party Central Committee with a sense of ideological will and devotion. The power of unity and solidarity which place the party and the leader at...there is to be further strengthening of a unity and solidarity which place the party and the leader at the center in accordance with the

A discussion of cone and flat-plate Reynolds numbers for equal ratios of the laminar shear to the shear caused by small velocity fluctuations in a laminar boundary layer

NASA Technical Reports Server (NTRS)

Tetervin, Neal

1957-01-01

By use of the linear theory of boundary-layer stability and Schlichting's formula for the maximum amplification of a disturbance, an approximate relation is derived between the Reynolds number on a cone and the Reynolds number on a flat plate for equal closeness to transition. The indication is that the ratio of the cone Reynolds number for transition, based on the distance to the cone apex, to the plate Reynolds number for transition, based on the distance to the leading edge, is not in general equal to 3, as has been suggested by other investigators, but varies from 3 when transition occurs at the minimum critical Reynolds number to unity when transition occurs at a large multiple of the critical Reynolds number.

Fluctuations in an established transmission in the presence of a complex environment

NASA Astrophysics Data System (ADS)

Savin, Dmitry V.; Richter, Martin; Kuhl, Ulrich; Legrand, Olivier; Mortessagne, Fabrice

2017-09-01

In various situations where wave transport is preeminent, like in wireless communication, a strong established transmission is present in a complex scattering environment. We develop a nonperturbative approach to describe emerging fluctuations which combines a transmitting channel and a chaotic background in a unified effective Hamiltonian. Modeling such a background by random matrix theory, we derive exact results for both transmission and reflection distributions at arbitrary absorption that is typically present in real systems. Remarkably, in such a complex scattering situation, the transport is governed by only two parameters: an absorption rate and the ratio of the so-called spreading width to the natural width of the transmission line. In particular, we find that the established transmission disappears sharply when this ratio exceeds unity. The approach exemplifies the role of the chaotic background in dephasing the deterministic scattering.

Magnetization of AGN jets as imposed by leptonic models of luminous blazars

NASA Astrophysics Data System (ADS)

Janiak, Mateusz; Sikora, Marek; Moderski, Rafal

2015-03-01

Recent measurements of frequency-dependent shift of radio-core locations indicate that the ratio of the magnetic to kinetic energy flux (the σ parameter) is of the order of unity. These results are consistent with predictions of magnetically-arrested-disk (MAD) models of a jet formation, but contradict the predictions of leptonic models of γ-ray production in luminous blazars. We demonstrate this discrepancy by computing the γ-ray-to-synchrotron luminosity ratio (the q parameter) as a function of a distance from the black hole for different values of σ and using both spherical and planar models for broad-line region and dusty torus. We find that it is impossible to reproduce observed q >> 1 for jets with σ >= 1. This may indicate that blazar radiation is produced in reconnection layers or in spines of magnetically stratified jets.

Assessing the Role of the 'Unity Assumption' on Multisensory Integration: A Review.

PubMed

Chen, Yi-Chuan; Spence, Charles

2017-01-01

There has been longstanding interest from both experimental psychologists and cognitive neuroscientists in the potential modulatory role of various top-down factors on multisensory integration/perception in humans. One such top-down influence, often referred to in the literature as the 'unity assumption,' is thought to occur in those situations in which an observer considers that various of the unisensory stimuli that they have been presented with belong to one and the same object or event (Welch and Warren, 1980). Here, we review the possible factors that may lead to the emergence of the unity assumption. We then critically evaluate the evidence concerning the consequences of the unity assumption from studies of the spatial and temporal ventriloquism effects, from the McGurk effect, and from the Colavita visual dominance paradigm. The research that has been published to date using these tasks provides support for the claim that the unity assumption influences multisensory perception under at least a subset of experimental conditions. We then consider whether the notion has been superseded in recent years by the introduction of priors in Bayesian causal inference models of human multisensory perception. We suggest that the prior of common cause (that is, the prior concerning whether multisensory signals originate from the same source or not) offers the most useful way to quantify the unity assumption as a continuous cognitive variable.

INFLUENCE OF SCALE RATIO, ASPECT RATIO, AND PLANFORM ON THE PERFORMANCE OF SUPERCAVITATING HYDROFOILS.

DTIC Science & Technology

performance of supercavitating hydrofoils. No appreciable scale effect was found for scale ratios up to 3 in the fully-cavitating flow region. The...overall performance of the hydrofoil by increasing the aspect ratio above 3, and (2) moderate taper ratio seems to be advantageous in view of the overall performance of supercavitating hydrofoils. (Author)

Unity with PMA-2 attached awaits further processing in the SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

The International Space Station's (ISS) Unity node, with Pressurized Mating Adapter (PMA)-2 attached, awaits further processing by Boeing technicians in its workstand in the Space Station Processing Facility (SSPF). The Unity node is the first element of the ISS to be manufactured in the United States and is currently scheduled to lift off aboard the Space Shuttle Endeavour on STS-88 later this year. Unity has two PMAs attached to it now that this mate is completed. PMAs are conical docking adapters which will allow the docking systems used by the Space Shuttle and by Russian modules to attach to the node's hatches and berthing mechanisms. Once in orbit, Unity, which has six hatches, will be mated with the already orbiting Control Module and will eventually provide attachment points for the U.S. laboratory module; Node 3; an early exterior framework or truss for the station; an airlock; and a multi-windowed cupola. The Control Module, or Functional Cargo Block, is a U.S.-funded and Russian-built component that will be launched aboard a Russian rocket from Kazakstan.

Unity with PMA-2 attached awaits further processing in the SSPF

NASA Technical Reports Server (NTRS)

1998-01-01

The International Space Station's (ISS) Unity node, with Pressurized Mating Adapter (PMA)-2 attached, awaits further processing in the Space Station Processing Facility (SSPF). The Unity node is the first element of the ISS to be manufactured in the United States and is currently scheduled to lift off aboard the Space Shuttle Endeavour on STS-88 later this year. Unity has two PMAs attached to it now that this mate is completed. PMAs are conical docking adapters which will allow the docking systems used by the Space Shuttle and by Russian modules to attach to the node's hatches and berthing mechanisms. Once in orbit, Unity, which has six hatches, will be mated with the already orbiting Control Module and will eventually provide attachment points for the U.S. laboratory module; Node 3; an early exterior framework or truss for the station; an airlock; and a multi-windowed cupola. The Control Module, or Functional Cargo Block, is a U.S.- funded and Russian-built component that will be launched aboard a Russian rocket from Kazakstan.

Unity of consciousness.

PubMed

Hill, Christopher S

2018-05-29

Although there is much talk in various literatures of streams of consciousness, and most of us have an intuitive understanding of such talk, we are far from having a full grasp of what it is that unifies streams of consciousness, binding together the individual experiences that serve as their constituents. In recent years, discussion of this topic has been principally concerned with synchronic unity of consciousness-the form of unity that is exhibited by momentary states of consciousness, or in other words, by time slices or temporal segments of streams. There are two main questions about synchronic unity. First, what is its scope? Are the simultaneous experiences of a single subject necessarily unified? Generally but not necessarily unified? Sometimes unified? And second, what is the nature of synchronic unity? Is it a fundamental phenomenon, and if not, what are the more basic phenomena that constitute it? This essay reviews recent work on these questions, and provides reasons for preferring some answers to others. This article is categorized under: Philosophy > Consciousness Philosophy > Foundations of Cognitive Science Philosophy > Metaphysics. © 2018 Wiley Periodicals, Inc.

On virial analysis at low aspect ratio

DOE PAGES

Bongard, Michael W.; Barr, Jayson L.; Fonck, Raymond J.; ...

2016-07-28

The validity of virial analysis to infer global MHD equilibrium poloidal beta β p and internal inductance ℓ i from external magnetics measurements is examined for low aspect ratio configurations with A < 2. Numerical equilibrium studies at varied aspect ratio are utilized to validate the technique at finite aspect ratio. The effect of applying high-A approximations to low-A experimental data is quantified and demonstrates significant over-estimation of stored energy (factors of 2–10) in spherical tokamak geometry. Experimental approximations to equilibrium-dependent volume integral terms in the analysis are evaluated at low-A. Highly paramagnetic configurations are found to be inadequately representedmore » through the virial mean radius parameter R T. Alternate formulations for inferring β p and ℓ i that are independent of R T to avoid this difficulty are presented for the static isotropic limit. Lastly, these formulations are suitable for fast estimation of tokamak stored energy components at low aspect ratio using virial analysis.« less

Framework to model neutral particle flux in convex high aspect ratio structures using one-dimensional radiosity

NASA Astrophysics Data System (ADS)

Manstetten, Paul; Filipovic, Lado; Hössinger, Andreas; Weinbub, Josef; Selberherr, Siegfried

2017-02-01

We present a computationally efficient framework to compute the neutral flux in high aspect ratio structures during three-dimensional plasma etching simulations. The framework is based on a one-dimensional radiosity approach and is applicable to simulations of convex rotationally symmetric holes and convex symmetric trenches with a constant cross-section. The framework is intended to replace the full three-dimensional simulation step required to calculate the neutral flux during plasma etching simulations. Especially for high aspect ratio structures, the computational effort, required to perform the full three-dimensional simulation of the neutral flux at the desired spatial resolution, conflicts with practical simulation time constraints. Our results are in agreement with those obtained by three-dimensional Monte Carlo based ray tracing simulations for various aspect ratios and convex geometries. With this framework we present a comprehensive analysis of the influence of the geometrical properties of high aspect ratio structures as well as of the particle sticking probability on the neutral particle flux.

A review on non-linear aeroelasticity of high aspect-ratio wings

NASA Astrophysics Data System (ADS)

Afonso, Frederico; Vale, José; Oliveira, Éder; Lau, Fernando; Suleman, Afzal

2017-02-01

Current economic constraints and environmental regulations call for design of more efficient aircraft configurations. An observed trend in aircraft design to reduce the lift induced drag and improve fuel consumption and emissions is to increase the wing aspect-ratio. However, a slender wing is more flexible and subject to higher deflections under the same operating conditions. This effect may lead to changes in dynamic behaviour and in aeroelastic response, potentially resulting in instabilities. Therefore, it is important to take into account geometric non-linearities in the design of high aspect-ratio wings, as well as having accurate computational codes that couple the aerodynamic and structural models in the presence of non-linearities. Here, a review on the state-of-the-art on non-linear aeroelasticity of high aspect-ratio wings is presented. The methodologies employed to analyse high aspect-ratio wings are presented and their applications discussed. Important observations from the state-of-the-art studies are drawn and the current challenges in the field are identified.

An Analysis of the Effects of Wing Aspect Ratio and Tail Location on Static Longitudinal Stability Below the Mach Number of Lift Divergence

NASA Technical Reports Server (NTRS)

Axelson, John A.; Crown, J. Conrad

1948-01-01

An analysis is presented of the influence of wing aspect ratio and tail location on the effects of compressibility upon static longitudinal stability. The investigation showed that the use of reduced wing aspect ratios or short tail lengths leads to serious reductions in high-speed stability and the possibility of high-speed instability.

A numerical simulation of finite-length Taylor-Couette flow

NASA Technical Reports Server (NTRS)

Streett, C. L.; Hussaini, M. Y.

1988-01-01

Results from numerical simulations of finite-length Taylor-Couette flow are presented. Included are time-accurate and steady-state studies of the change in the nature of the symmetric two-cell/asymmetric one-cell bifurcation with varying aspect ratio and of the Reynolds number/aspect ratio locus of the two-cell/four-cell bifurcation. Preliminary results from wavy-vortex simulations at low aspect ratios are also presented.

Soft-lithography fabrication of microfluidic features using thiol-ene formulations.

PubMed

Ashley, John F; Cramer, Neil B; Davis, Robert H; Bowman, Christopher N

2011-08-21

In this work, a novel thiol-ene based photopolymerizable resin formulation was shown to exhibit highly desirable characteristics, such as low cure time and the ability to overcome oxygen inhibition, for the photolithographic fabrication of microfluidic devices. The feature fidelity, as well as various aspects of the feature shape and quality, were assessed as functions of various resin attributes, particularly the exposure conditions, initiator concentration and inhibitor to initiator ratio. An optical technique was utilized to evaluate the feature fidelity as well as the feature shape and quality. These results were used to optimize the thiol-ene resin formulation to produce high fidelity, high aspect ratio features without significant reductions in feature quality. For structures with aspect ratios below 2, little difference (<3%) in feature quality was observed between thiol-ene and acrylate based formulations. However, at higher aspect ratios, the thiol-ene resin exhibited significantly improved feature quality. At an aspect ratio of 8, raised feature quality for the thiol-ene resin was dramatically better than that achieved by using the acrylate resin. The use of the thiol-ene based resin enabled fabrication of a pinched-flow microfluidic device that has complex channel geometry, small (50 μm) channel dimensions, and high aspect ratio (14) features. This journal is © The Royal Society of Chemistry 2011

Modeling of Turbulent Natural Convection in Enclosed Tall Cavities

NASA Astrophysics Data System (ADS)

Goloviznin, V. M.; Korotkin, I. A.; Finogenov, S. A.

2017-12-01

It was shown in our previous work (J. Appl. Mech. Tech. Phys 57 (7), 1159-1171 (2016)) that the eddy-resolving parameter-free CABARET scheme as applied to two-and three-dimensional de Vahl Davis benchmark tests (thermal convection in a square cavity) yields numerical results on coarse (20 × 20 and 20 × 20 × 20) grids that agree surprisingly well with experimental data and highly accurate computations for Rayleigh numbers of up to 1014. In the present paper, the sensitivity of this phenomenon to the cavity shape (varying from cubical to highly elongated) is analyzed. Box-shaped computational domains with aspect ratios of 1: 4, 1: 10, and 1: 28.6 are considered. The results produced by the CABARET scheme are compared with experimental data (aspect ratio of 1: 28.6), DNS results (aspect ratio of 1: 4), and an empirical formula (aspect ratio of 1: 10). In all the cases, the CABARET-based integral parameters of the cavity flow agree well with the other authors' results. Notably coarse grids with mesh refinement toward the walls are used in the CABARET calculations. It is shown that acceptable numerical accuracy on extremely coarse grids is achieved for an aspect ratio of up to 1: 10. For higher aspect ratios, the number of grid cells required for achieving prescribed accuracy grows significantly.

Microwave synthesis and photocatalytic activities of ZnO bipods with different aspect ratios

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

Sun, Fazhe; Zhao, Zengdian; Qiao, Xueliang, E-mail: xuelqiao@163.com

2016-02-15

Highlights: • We synthesized linked ZnO nanorods by a facile microwave method. • The effect of reaction parameters on ZnO was investigated. • ZnO bipods with different aspect ratios were prepared. • The photocatalytic performance of ZnO bipods was evaluated. - Abstract: Linked ZnO nanorods have been successfully prepared via a facile microwave method without any post-synthesis treatment. The X-ray diffraction (XRD) patterns indicated the precursor had completely transformed into the pure ZnO crystal. The images of field emitting scanning electron microscope (FESEM) and transmission electron microscope (TEM) showed that linked ZnO nanorods consisted predominantly of ZnO bipods. The formationmore » process of the ZnO bipods was clearly discussed. ZnO bipods with different aspect ratios have been obtained by tuning the concentrations of reagents and microwave power. Moreover, the photocatalytic performance of ZnO bipods with different aspect ratios for degradation of methylene blue was systematically evaluated. The results of photocatalytic experiments showed that the photocatalytic activity increased with the aspect ratios of ZnO bipods increased. The reason is that ZnO bipods with larger aspect ratio have higher surface area, which can absorb more MB molecules to react with ·OH radicals.« less

Hydrodynamic thrust generation and power consumption investigations for piezoelectric fins with different aspect ratios

NASA Astrophysics Data System (ADS)

Shahab, S.; Tan, D.; Erturk, A.

2015-12-01

Bio-inspired hydrodynamic thrust generation using piezoelectric transduction has recently been explored using Macro-Fiber Composite (MFC) actuators. The MFC technology strikes a balance between the actuation force and structural deformation levels for effective swimming performance, and additionally offers geometric scalability, silent operation, and ease of fabrication. Recently we have shown that mean thrust levels comparable to biological fish of similar size can be achieved using MFC fins. The present work investigates the effect of length-to-width (L/b) aspect ratio on the hydrodynamic thrust generation performance of MFC cantilever fins by accounting for the power consumption level. It is known that the hydrodynamic inertia and drag coefficients are controlled by the aspect ratio especially for L/b< 5. The three MFC bimorph fins explored in this work have the aspect ratios of 2.1, 3.9, and 5.4. A nonlinear electrohydroelastic model is employed to extract the inertia and drag coefficients from the vibration response to harmonic actuation for the first bending mode. Experiments are then conducted for various actuation voltage levels to quantify the mean thrust resultant and power consumption levels for different aspect ratios. Variation of the thrust coefficient of the MFC bimorph fins with changing aspect ratio is also semi-empirically modeled and presented.

Integrated But Not Whole? Applying an Ontological Account of Human Organismal Unity to the Brain Death Debate.

PubMed

Moschella, Melissa

2016-10-01

As is clear in the 2008 report of the President's Council on Bioethics, the brain death debate is plagued by ambiguity in the use of such key terms as 'integration' and 'wholeness'. Addressing this problem, I offer a plausible ontological account of organismal unity drawing on the work of Hoffman and Rosenkrantz, and then apply that account to the case of brain death, concluding that a brain dead body lacks the unity proper to a human organism, and has therefore undergone a substantial change. I also show how my view can explain hard cases better than one in which biological integration (as understood by Alan Shewmon and the President's Council) is taken to imply ontological wholeness or unity. © 2016 John Wiley & Sons Ltd.

International Space Station (ISS)

NASA Image and Video Library

1997-01-01

This photograph, taken by the Boeing Company,shows Boeing technicians preparing to install one of six hatches or doors to the Node 1 (also called Unity), the first U.S. Module for the International Space Station (ISS). The Node 1, or Unity, serves as a cornecting passageway to Space Station modules and was manufactured by the Boeing Company at the Marshall Space Flight Center from 1994 to 1997. The U.S. built Unity module was launched aboard the orbiter Endeavour (STS-88 mission) on December 4, 1998 and connected to the Zarya, the Russian-built Functional Energy Block (FGB). The Zarya was launched on a Russian proton rocket prior to the launch of the Unity. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation.

International Space Station (ISS)

NASA Image and Video Library

1997-01-01

This photograph, taken by the Boeing Company, shows Boeing technicians preparing to install one of six hatches or doors to the Node 1 (also called Unity), the first U.S. Module for the International Space Station (ISS). The Node 1, or Unity, serves as a cornecting passageway to Space Station modules and was manufactured by the Boeing Company at the Marshall Space Flight Center from 1994 to 1997. The U.S. built Unity module was launched aboard the orbiter Endeavour (STS-88 mission) on December 4, 1998 and connected to the Zarya, the Russian-built Functional Energy Block (FGB). The Zarya was launched on a Russian proton rocket prior to the launch of the Unity. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation.

Some Effects of Sweep and Aspect Ratio on the Transonic Flutter Characteristics of a Series of Thin Cantilever Wings Having a Taper Ratio of 0.6

NASA Technical Reports Server (NTRS)

Jones, G. W., Jr.; Unangst, J. R.

1963-01-01

An investigation of the flutter characteristics of a series of thin cantilever wings having taper ratios of 0.6 was conducted in the Langley transonic blowdown tunnel at Mach numbers between 0.76 and 1.42. The angle of sweepback was varied from 0 degrees to 60 degrees on wings of aspect ratio 4, and the aspect ratio was varied from 2.4 to 6.4 on wings with 45 degrees of sweepback. The results are presented as ratios between the experimental flutter speeds and the reference flutter speeds calculated on the basis of incompressible two-dimensional flow. These ratios, designated the flutter-speed ratios, are given as functions of Mach number for the various wings. The flutter-speed ratios were characterized, in most cases, by values near 1.0 at subsonic speeds with large increases in the speed ratios in the range of supersonic speeds investigated. Increasing the sweep effected increases in the flutter-speed ratios between 0 degrees and 30 degrees followed by progressive reductions of the speed ratios to nearly 1.0 as the sweep was increased from 30 degrees to 60 degrees. Reducing the aspect ratio from 6.4 to 2.4 resulted in progressively larger values of the flutter-speed ratios throughout the Mach number range investigated.

Carbonate pore system evaluation using the velocity-porosity-pressure relationship, digital image analysis, and differential effective medium theory

NASA Astrophysics Data System (ADS)

Lima Neto, Irineu A.; Misságia, Roseane M.; Ceia, Marco A.; Archilha, Nathaly L.; Oliveira, Lucas C.

2014-11-01

Carbonate reservoirs exhibit heterogeneous pore systems and a wide variety of grain types, which affect the rock's elastic properties and the reservoir parameter relationships. To study the Albian carbonates in the Campos Basin, a methodology is proposed to predict the amount of microporosity and the representative aspect ratio of these inclusions. The method assumes three pore-space scales in two representative inclusion scenarios: 1) a macro-mesopore median aspect ratio from the thin-section digital image analysis (DIA) and 2) a microporosity aspect ratio predicted based on the measured P-wave velocities. Through a laboratory analysis of 10 grainstone core samples of the Albian age, the P- and S-wave velocities (Vp and Vs) are evaluated at effective pressures of 0-10 MPa. The analytical theories in the proposed methodology are functions of the aspect ratios from the differential effective medium (DEM) theory, the macro-mesopore system recognized from the DIA, the amount of microporosity determined by the difference between the porosities estimated from laboratorial helium-gas and the thin-section petrographic images, and the P-wave velocities under dry effective pressure conditions. The DIA procedure is applied to estimate the local and global parameters, and the textural implications concerning ultrasonic velocities and image resolution. The macro-mesopore inclusions contribute to stiffer rocks and higher velocities, whereas the microporosity inclusions contribute to softer rocks and lower velocities. We observe a high potential for this methodology, which uses the microporosity aspect ratio inverted from Vp to predict Vs with a good agreement. The results acceptably characterize the Albian grainstones. The representative macro-mesopore aspect ratio is 0.5, and the inverted microporosity aspect ratio ranges from 0.01 to 0.07. The effective pressure induced an effect of slight porosity reduction during the triaxial tests, mainly in the microporosity inclusions, slightly changing the amount and the aspect ratio of the microporosity.

View of the STS-88 crew in the Node 1/Unity module

NASA Image and Video Library

1998-12-10

STS088-322-021 (4-15 DECEMBER 1998) --- Astronaut Robert D. Cabana (left), mission commander, and cosmonaut Sergei K. Krikalev, mission specialist representing the Russian Space Agency (RSA), plan their approach to tasks in the U.S.-built Unity module. All six STS-88 crew members were involved in tasks to ready Unity and the now-connected Russian-built FGB module, also called Zarya, for their International Space Station (ISS) roles. Krikalev has been named as a member of the first ISS crew.

Unity connecting module in the Space Station Processing Facility

NASA Technical Reports Server (NTRS)

1998-01-01

Unity connecting module, part of the International Space Station, awaits processing in the Space Station Processing Facility (SSPF). On the end at the right can be seen the Pressurized Mating Adapter 2, which provides entry into the module. The Unity, scheduled to be launched on STS-88 in December 1998, will be mated to the Russian-built Zarya control module which will already be in orbit. STS-88 will be the first Space Shuttle launch for the International Space Station.

Infusion of a Gaming Paradigm into Computer-Aided Engineering Design Tools

DTIC Science & Technology

2012-05-03

Virtual Test Bed (VTB), and the gaming tool, Unity3D . This hybrid gaming environment coupled a three-dimensional (3D) multibody vehicle system model...from Google Earth to the 3D visual front-end fabricated around Unity3D . The hybrid environment was sufficiently developed to support analyses of the...ndFr Cti3r4 G’OjrdFr ctior-2 The VTB simulation of the vehicle dynamics ran concurrently with and interacted with the gaming engine, Unity3D which

Long-lived Eccentric modes in Protoplanetary Disks

NASA Astrophysics Data System (ADS)

Lee, Wing-Kit; Dempsey, Adam M.; Lithwick, Yoram

2018-04-01

A theory is developed to understand global eccentric modes that are slowly precessing in protoplanetary disks. Using the typical self-similar density profiles, we found that these modes are trapped in the disk and are not sensitive to the uncertain boundary condition at the disk edge. This is contrary to common wisdom that the modes can only exist in disks with very sharp outer edge. Because of their discrete spectrum, once excited, a perturbed disk can stay eccentric for a long time until the mode is viscously damped. The physics behind the mode trapping depends ultimately on the relative importance of gas pressure and self-gravity, which is characterized by g = 1/ (Q h), where h is the disk aspect ratio and Q is the Toomre stability parameter. A very low mass disk (g ≪ 1) is pressure-dominated and supports pressure modes, in which the eccentricity is highest at the disk edge. The modes are trapped by a turning point due to the density drop in the outer disk. For a more massive disk with g of order of unity (Q~1/h~10-100), prograde modes are supported. Unlike the pressure modes, these modes are trapped by Q-barriers and result in a bump in the radial eccentricity profile. As the mode trapping is a generic phenomenon for typical disk profiles, the free linear eccentric modes are likely to be present in protoplanetary disks with a wide range of disk mass.

On the pollutant removal, dispersion, and entrainment over two-dimensional idealized street canyons

NASA Astrophysics Data System (ADS)

Liu, Chun-Ho; Wong, Colman C. C.

2014-01-01

Pollutant dispersion over urban areas is not that well understood, in particular at the street canyon scale. This study is therefore conceived to examine how urban morphology modifies the pollutant removal, dispersion, and entrainment over urban areas. An idealized computational domain consisting of 12 two-dimensional (2D) identical street canyons of unity aspect ratio is employed. The large-eddy simulation (LES) is used to calculate the turbulent flows and pollutant transport in the urban boundary layer (UBL). An area source of uniform pollutant concentration is applied on the ground of the first street canyon. A close examination on the roof-level turbulence reveals patches of low-speed air masses in the streamwise flows and narrow high-speed downdrafts in the shear layer. Different from the flows over a smooth surface, the turbulence intensities are peaked near the top of the building roughness. The pollutant is rather uniformly distributed inside a street canyon but disperses quickly in the UBL over the buildings. Partitioning the vertical pollutant flux into its mean and turbulent components demystifies that the pollutant removal is mainly governed by turbulence. Whereas, mean wind carries pollutant into and out of a street canyon simultaneously. In addition to wind speed promotion, turbulent mixing is thus required to dilute the ground-level pollutants, which are then removed from the street canyon to the UBL. Atmospheric flows slow down rapidly after the leeward buildings, leading to updrafts carrying pollutants away from the street canyons (the basic pollutant removal mechanism).

Wind Tunnel Measurements of Turbulent Boundary Layer over Hypothetical Urban Roughness Elements

NASA Astrophysics Data System (ADS)

Ho, Y. K.; Liu, C. H.

2012-04-01

Urban morphology affects the near-ground atmospheric boundary layer that in turn modifies the wind flows and pollutant dispersion over urban areas. A number of numerical models (large-eddy simulation, LES and k-ɛ turbulence models) have been developed to elucidate the transport processes in and above urban street canyons. To complement the modelling results, we initiated a wind tunnel study to examine the influence of idealized urban roughness on the flow characteristics and pollutant dispersion mechanism over 2D idealized street canyons placed in cross flows. Hot-wire anemometry (HWA) was employed in this study to measure the flows over 2D street canyons in the wind tunnel in our university. Particular focus in the beginning stage was on the fabrication of hot-wire probes, data acquisition system, and signal processing technique. Employing the commonly adopted hot-wire universal function, we investigated the relationship in between and developed a scaling factor which could generalize the output of our hot-wire probes to the standardized one as each hot-wire probes has its unique behaviour. Preliminary experiments were performed to measure the wind flows over street canyons of unity aspect ratio. Vertical profiles of the ensemble average velocity and fluctuations at three different segments over the street canyons were collected. The results were then compared with our LES that show a good argument with each other. Additional experiments are undertaken to collect more data in order to formulate the pollutant dispersion mechanism of street canyons and urban areas.

Convective instability in a porous enclosure with a horizontal conducting baffle

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

Chen, F.; Wang, C.Y.

1993-08-01

The study of heat transfer in a fluid-saturated porous medium is essential in a variety of practical situations, including thermal insulation design and geothermal energy utilization. The present paper studies the convective instability in a two-dimensional porous enclosure with a horizontal baffle protruding from one of the side walls. The vertical side walls are insulated, while the top and bottom surfaces are maintained at lower and higher constant temperatures, respectively. The present work considers a baffle of high conductivity. We assume the baffle temperature can be considered constant throughout. We ask, for a given enclosure aspect ratio, is the additionmore » of another physical constraint (such as lengthening a baffle) always stabilizing Is there an optimum baffle location and length such that the critical Rayleigh number is maximized In summary, several concluding remarks can be drawn in the following: (1) Other dimensions being same, a centered baffle always results in a more stable state than an off-centered baffle. (2) A full-length baffle, i.e., [beta]/[sigma] = 1, does not necessarily lead to greater stability. Instead, the value of ([beta]/[sigma])[sub max] is usually less than unity. For a centered baffle, the maximum R[sup c] occurs for [beta]/[sigma] [ge] ([beta]/[sigma])[sub max]; while for an off-centered baffle, the maximum R[sup c] occurs at ([beta]/[sigma])[sub max]. (3) The value of ([beta]/[sigma])[sub max] increases with [sigma]. 6 refs., 4 figs., 1 tab.« less

Noncommutative reading of the complex plane through Delone sequences

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

Ali, S. Twareque; Balkova, Lubka; Gazeau, J. P.

2009-04-15

The Berezin-Klauder-Toeplitz ('anti-Wick') quantization or 'noncommutative reading' of the complex plane, viewed as the phase space of a particle moving on the line, is derived from the resolution of the unity provided by the standard (or Gaussian) coherent states. The construction of these states and their attractive properties are essentially based on the energy spectrum of the harmonic oscillator, that is, on the natural numbers. This work is an attempt for following the same path by considering sequences of non-negative numbers which are not 'too far' from the natural numbers. In particular, we examine the consequences of such perturbations onmore » the noncommutative reading of the complex plane in terms of its probabilistic, functional, and localization aspects.« less

Experiments on two- and three-dimensional vortex flows in lid-driven cavities

NASA Astrophysics Data System (ADS)

Siegmann-Hegerfeld, Tanja; Albensoeder, Stefan; Kuhlmann, Hendrik C.

2009-11-01

Vortex flows in one-sided lid-driven cavities with different cross-sectional aspect ratios (γ = 0.26 up to γ = 6.3) are investigated experimentally. In all cases the spanwise aspect ratio λ>>γ is very large and much larger than most previous experiments. Flow-structure visualizations will be presented together with quantitative LDA and PIV measurements. The experimental results are in good agreement with the critical data from numerical stability analyses and with nonlinear simulations. Experimentally, we find four different three-dimensional instabilities. Particular attention is paid to the so-called C4 mode which arises at large cross-sectional aspect ratios. When the spanwise aspect ratio is small the first bifurcation of the C4 mode is strongly imperfect.

Computational Modeling And Analysis Of Synthetic Jets

NASA Technical Reports Server (NTRS)

Mittal, Rajat; Cattafesta, Lou

2005-01-01

In the last report we focused on the study of 3D synthetic jets of moderate jet aspect-ratio. Jets in quiescent and cross-flow cases were investigated. Since most of the synthetic jets in practical applications are found to be of large aspect ratio, the focus was shifted to studying synthetic jets of large aspect ratio. In the current year, further progress has been made by studying jets of aspect ratio 8 and infinity. Some other aspects of the jet, like the vorticity flux is looked into apart from analyzing the vortex dynamics, velocity profiles and the other dynamical characteristics of the jet which allows us to extract some insight into the effect of these modifications on the jet performance. Also, efforts were made to qualitatively validate the simulated results with the NASA Langley test cases at higher jet Reynolds number for the quiescent jet case.

Tyurin with guitar in Node 1 / Unity module

NASA Image and Video Library

2007-01-19

ISS014-E-12466 (19 Jan. 2007) --- Cosmonaut Mikhail Tyurin, Expedition 14 flight engineer representing Russia's Federal Space Agency, plays a guitar in the Unity node of the International Space Station.

Poindexter in Node 1 Unity

NASA Image and Video Library

2010-04-10

S131-E-008504 (10 April 2010) --- NASA astronaut Alan Poindexter, STS-131 commander, floats freely in the Unity node of the International Space Station while space shuttle Discovery remains docked with the station.

The Nature, Significance, and Evaluation of the Schwarzschild-Villiger (SV) Effect in Photometric Procedures

PubMed Central

Howling, D. H.; Fitzgerald, P. J.

1959-01-01

The Schwarzschild-Villiger effect has been experimentally demonstrated with the optical system used in this laboratory. Using a photographic mosaic specimen as a model, it has been shown that the conclusions of Naora are substantiated and that the SV effect, in large or small magnitude, is always present in optical systems. The theoretical transmission error arising from the presence of the SV effect has been derived for various optical conditions of measurement. The results have been experimentally confirmed. The SV contribution of the substage optics of microspectrophotometers has also been considered. A simple method of evaluating a flare function f(A) is advanced which provides a measure of the SV error present in a system. It is demonstrated that measurements of specimens of optical density less than unity can be made with less than 1 per cent error, when using illuminating beam diameter/specimen diameter ratios of unity and uncoated optical surfaces. For denser specimens it is shown that care must be taken to reduce the illuminating beam/specimen diameter ratio to a value dictated by the magnitude of a flare function f(A), evaluated for a particular optical system, in order to avoid excessive transmission error. It is emphasized that observed densities (transmissions) are not necessarily true densities (transmissions) because of the possibility of SV error. The ambiguity associated with an estimation of stray-light error by means of an opaque object has also been demonstrated. The errors illustrated are not necessarily restricted to microspectrophotometry but may possibly be found in such fields as spectral analysis, the interpretation of x-ray diffraction patterns, the determination of ionizing particle tracks and particle densities in photographic emulsions, and in many other types of photometric analysis. PMID:14403512

Deformation mechanisms in negative Poisson's ratio materials - Structural aspects

NASA Technical Reports Server (NTRS)

Lakes, R.

1991-01-01

Poisson's ratio in materials is governed by the following aspects of the microstructure: the presence of rotational degrees of freedom, non-affine deformation kinematics, or anisotropic structure. Several structural models are examined. The non-affine kinematics are seen to be essential for the production of negative Poisson's ratios for isotropic materials containing central force linkages of positive stiffness. Non-central forces combined with pre-load can also give rise to a negative Poisson's ratio in isotropic materials. A chiral microstructure with non-central force interaction or non-affine deformation can also exhibit a negative Poisson's ratio. Toughness and damage resistance in these materials may be affected by the Poisson's ratio itself, as well as by generalized continuum aspects associated with the microstructure.

A study of the rheology and micro-structure of dumbbells in shear geometries

NASA Astrophysics Data System (ADS)

Mandal, Sandip; Khakhar, D. V.

2018-01-01

We study the flow of frictional, inelastic dumbbells made of two fused spheres of different aspect ratios down a rough inclined plane and in a simple shear cell, using discrete element simulations. At a fixed inclination angle, the mean velocity decreases, and the volume fraction increases significantly with increasing aspect ratio in the chute flow. At a fixed solid fraction, the shear stress and pressure decrease significantly with increasing aspect ratio in the shear cell flow. The micro-structure of the flow is characterized. The translational diffusion coefficient in the normal direction to the flow is found to scale as Dy y=b γ ˙ d2, independent of aspect ratio, where b is a constant, γ ˙ is the shear rate, and d is the diameter of the constituent spheres of the dumbbells. The effective friction coefficient (μ, the ratio of shear stress to pressure) increases by 30%-35% on increasing the aspect ratio λ, from 1.0 to 1.7, for a fixed inertial number I. The volume fraction (ϕ) also increases significantly with increasing aspect ratio, especially at high inertial numbers. The effective friction coefficient and volume fraction are found to follow simple scalings of the form μ = μ(I, λ) and ϕ = ϕ(I, λ) for all the data from both systems, and the results are in reasonable agreement with kinetic theory predictions at low I. The computational results are in reasonable agreement with the experimental data for flow in a rotating cylinder.

Wheelock floats into Node 1 / Unity module

NASA Image and Video Library

2006-10-25

S120-E-006435 (25 Oct. 2007) --- Astronaut Doug Wheelock, STS-120 mission specialist, floats into the Unity node of the International Space Station while Space Shuttle Discovery is docked with the station.

CFD Assessment of Orifice Aspect Ratio and Mass Flow Ratio on Jet Mixing in Rectangular Ducts

NASA Technical Reports Server (NTRS)

Bain, D. B.; Smith, C. E.; Holdeman, J. D.

1994-01-01

Isothermal CFD analysis was performed on axially opposed rows of jets mixing with cross flow in a rectangular duct. Laterally, the jets' centerlines were aligned with each other on the top and bottom walls. The focus of this study was to characterize the effects of orifice aspect ratio and jet-to-mainstream mass flow ratio on jet penetration and mixing. Orifice aspect ratios (L/W) of 4-to-1, 2-to-1, and 1-to-1, along with circular holes, were parametrically analyzed. Likewise, jet-to-mainstream mass flow ratios (MR) of 2.0, 0.5, and 0.25 were systematically investigated. The jet-to-mainstream momentum-flux ratio (J) was maintained at 36 for all cases, and the orifice spacing-to-duct height (S/H) was varied until optimum mixing was attained for each configuration. The numerical results showed that orifice aspect ratio (and likewise orifice blockage) had little effect on jet penetration and mixing. Based on mixing characteristics alone, the 4-to-1 slot was comparable to the circular orifice. The 4-to-1 slot has a smaller jet wake which may be advantageous for reducing emissions. However, the axial length of a 4-to-1 slot may be prohibitively long for practical application, especially for MR of 2.0. The jet-to-mainstream mass flow ratio had a more significant effect on jet penetration and mixing. For a 4-to-1 aspect ratio orifice, the design correlating parameter for optimum mixing (C = (S/H)(sq. root J)) varied from 2.25 for a mass flow ratio of 2.0 to 1.5 for a mass flow ratio of 0.25.

Electrokinetic transport phenomena: Mobility measurement and electrokinetic instability

NASA Astrophysics Data System (ADS)

Oddy, Michael Huson

Miniaturization and integration of traditional bioassay procedures into microfabricated on-chip assay systems, commonly referred to as "Micro Total Analysis" (muTAS) systems, may have a significant impact on the fields of genomics, proteomics, and clinical analysis. These bioanalytical microsystems leverage electroosmosis and electrophoresis for sample transport, mixing, manipulation, and separation. This dissertation addresses the following three topics relevant to such systems: a new diagnostic for measuring the electrophoretic mobility of sub-micron, fluorescently-labeled particles and the electroosmotic mobility of a microchannel; a novel method and device for rapidly stirring micro- and nanoliter volume solutions for microfluidic bioanalytical applications; and a multiple-species electrokinetic instability model. Accurate measurement of the electrophoretic particle mobility and the electroosmotic mobility of microchannel surfaces is crucial to understanding the stability of colloidal suspensions, obtaining particle tracking-based velocimetry measurements of electroosmotic flow fields, and the quantification of electrokinetic bioanalytical device performance. A method for determining these mobilities from alternating and direct current electrokinetic particle tracking measurements is presented. The ability to rapidly mix fluids at low Reynolds numbers is important to the functionality of many bioanalytical, microfluidic devices. We present an electrokinetic process for rapidly stirring microflow streams by initiating an electrokinetic flow instability. The design, fabrication and performance analysis of two micromixing devices capable of rapidly stirring two low Reynolds number fluid streams are presented. Electroosmotic and electrophoretic transport in the presence of conductivity mismatches between reagent streams and the background electrolytes, can lead to an unstable flow field generating significant sample dispersion. In the multiple-species electrokinetic instability model, we consider a high aspect ratio microchannel geometry, a conductivity gradient orthogonal to the applied electric field, and a four-species chemistry model. A linear stability analysis of the depth-averaged governing equations shows unstable eigenmodes for conductivity ratios as close to unity as 1.01. Experiments and full nonlinear simulations of the governing equations were conducted for a conductivity ratio of 1.05. Images of the disturbance dye field from the nonlinear simulations show good qualitative and quantitative agreement with experiment. Species electromigration is shown to a have significant influence on the development of the conductivity field and instability dynamics in multi-ion configurations.

Sub-surface structures and collapse mechanisms of summit pit craters

NASA Astrophysics Data System (ADS)

Roche, O.; van Wyk de Vries, B.; Druitt, T. H.

2001-01-01

Summit pit craters are found in many types of volcanoes and are generally thought to be the product of collapse into an underpressured reservoir caused by magma withdrawal. We investigate the mechanisms and structures associated with summit pit crater formation by scaled analogue experiments and make comparisons with natural examples. Models use a sand plaster mixture as analogue rock over a cylinder of silicone simulating an underpressured magma reservoir. Experiments are carried out using different roof aspect ratios (roof thickness/roof width) of 0.2-2. They reveal two basic collapse mechanisms, dependant on the roof aspect ratio. One occurs at low aspect ratios (≤1), as illustrated by aspect ratios of 0.2 and 1. Outward dipping reverse faults initiated at the silicone margins propagates through the entire roof thickness and cause subsidence of a coherent block. Collapse along the reverse faults is accommodated by marginal flexure of the block and tension fractures at the surface (aspect ratio of 0.2) or by the creation of inward dipping normal faults delimiting a terrace (aspect ratio of 1). At an aspect ratio of 1, overhanging pit walls are the surface expressions of the reverse faults. Experiments at high aspect ratio (>1.2) reveal a second mechanism. In this case, collapse occurs by stopping, which propagates upwards by a complex pattern of both reverse faults and tension fractures. The initial underground collapse is restricted to a zone above the reservoir and creates a cavity with a stable roof above it. An intermediate mechanism occurs at aspect ratios of 1.1-1.2. In this case, stopping leads to the formation of a cavity with a thin and unstable roof, which collapses suddenly. The newly formed depression then exhibits overhanging walls. Surface morphology and structure of natural examples, such as the summit pit craters at Masaya Volcano, Nicaragua, have many of the features created in the models, indicating that the internal structural geometry of experiments can be applied to real examples. In particular, the surface area and depth of the underpressured reservoir can be roughly estimated. We present a morphological analysis of summit pit craters at volcanoes such as Kilimanjaro (Tanzania), San Cristobal, Telica and Masaya (Nicaragua), and Ubinas (Peru), and indicate a likely type of subsidence and possible position of the former magma reservoir responsible for collapse in each case.

Contact fatigue mechanisms as a function of crystal aspect ratio in baria-silicate glass ceramics

NASA Astrophysics Data System (ADS)

Suputtamongkol, Kallaya

2003-10-01

Ceramic materials are potentially useful for dental applications because of their esthetic potential and biocompatibility. However, the existence of fatigue damage in ceramics raises considerable concern regarding its effect on the life prediction of dental prostheses. During normal mastication, dental restorations are subjected to repeated loading more than a thousand times per day and relatively high clinical failure rates for ceramic prostheses have been reported. To simulate the intraoral loads, Hertzian indentation loading was used in this study to characterize the fatigue failure mechanisms of ceramic materials using clinically relevant parameters. The baria-silicate system was chosen because of the nearly identical composition between the crystal and the glass matrix. Little or no residual stress is expected from the elastic modulus and thermal expansion mismatches between the two phases. Crystallites with different aspect ratios can also be produced by controlled heat treatment schedules. The objective of this study was to characterize the effect of crystal morphology on the fatigue mechanisms of bariasilicate glass-ceramics under clinically relevant conditions. The results show that the failure of materials with a low toughness such as baria-silicate glass (0.7 MPa•m1/2) and glass-ceramic with an aspect ratio of 3/1 (1.3 MPa•m1/2) initiated from a cone crack developed during cyclic loading for 103 to 105 cycles. The mean strength values of baria-silicate glass and glass-ceramic with an aspect ratio of 3/1 decreased significantly as a result of the presence of a cone crack. Failure of baria-silicate glass-ceramics with an aspect ratio of 8/1 (Kc = 2.1 MPa•m1/2) was initiated from surface flaws caused by either polishing or cyclic loading. The gradual decrease of fracture stress was observed in specimens with an aspect ratio of 8/1 after loading in air for 103 to 10 5 cycles. A reduction of approximately 50% in fracture stress levels was found for specimens with an aspect ratio of 8/1 after loading for 10 5 cycles in deionized water. The mechanisms for cyclic fatigue crack propagation in baria-silicate glass-ceramics are similar to those observed under quasi-static loading conditions. An intergranular fracture path was observed in glass-ceramics with an aspect ratio of 3/1. For an aspect ratio of 8/1, a transgranular fracture mode was dominant.

Effect of aspect ratio on the mechanical behavior of packings of spheroids

NASA Astrophysics Data System (ADS)

Parafiniuk, Piotr; Bańda, Maciej; Stasiak, Mateusz; Horabik, Józef; Wiącek, Joanna; Molenda, Marek

2018-07-01

This paper presents measurements of the mechanical response of assemblages formed by spheroid particles. Sets of such particles in the form of thin, cylindrical samples were subjected to uniaxial confined compression. The particles were flattened and elongated, with aspect ratios ranging from 0.5 to 2.5. All particles were fabricated using a 3D printer and each had the same volume. Because the particles had well-defined shapes, it was possible to experimentally observe how the mechanical response of the anisotropic and highly constrained samples depended on the elongation of the particles. In particular, we showed how the sample density, lateral pressure ratio, and work done to compact a sample of elongated or flattened particles changed with change in particle aspect ratio. Furthermore, we found that the evolution of packing density in subsequent loading-unloading cycles followed a stretched exponential law regardless of particle aspect ratio.

Simultaneous fabrication of very high aspect ratio positive nano- to milliscale structures.

PubMed

Chen, Long Qing; Chan-Park, Mary B; Zhang, Qing; Chen, Peng; Li, Chang Ming; Li, Sai

2009-05-01

A simple and inexpensive technique for the simultaneous fabrication of positive (i.e., protruding), very high aspect (>10) ratio nanostructures together with micro- or millistructures is developed. The method involves using residual patterns of thin-film over-etching (RPTO) to produce sub-micro-/nanoscale features. The residual thin-film nanopattern is used as an etching mask for Si deep reactive ion etching. The etched Si structures are further reduced in size by Si thermal oxidation to produce amorphous SiO(2), which is subsequently etched away by HF. Two arrays of positive Si nanowalls are demonstrated with this combined RPTO-SiO(2)-HF technique. One array has a feature size of 150 nm and an aspect ratio of 26.7 and another has a feature size of 50 nm and an aspect ratio of 15. No other parallel reduction technique can achieve such a very high aspect ratio for 50-nm-wide nanowalls. As a demonstration of the technique to simultaneously achieve nano- and milliscale features, a simple Si nanofluidic master mold with positive features with dimensions varying continuously from 1 mm to 200 nm and a highest aspect ratio of 6.75 is fabricated; the narrow 200-nm section is 4.5 mm long. This Si master mold is then used as a mold for UV embossing. The embossed open channels are then closed by a cover with glue bonding. A high aspect ratio is necessary to produce unblocked closed channels after the cover bonding process of the nanofluidic chip. The combined method of RPTO, Si thermal oxidation, and HF etching can be used to make complex nanofluidic systems and nano-/micro-/millistructures for diverse applications.

Effects of aspect ratio of multi-walled carbon nanotubes on coal washery waste water treatment.

PubMed

Aliyu, Ahmed; Kariim, Ishaq; Abdulkareem, Saka Ambali

2017-11-01

The dependency of adsorption behaviour on the aspect ratio of multi-walled carbon nanotubes (MWCNTs) has been explored. In this study, effect of growth temperature on yield and aspect ratio of MWCNTs by catalytic chemical vapour deposition (CCVD) method is reported. The result revealed that yield and aspect ratio of synthesised MWCNTs strongly depend on the growth temperature during CCVD operation. The resulting MWCNTs were characterized by High Resolution Transmission Electron Microscope (HRTEM), Dynamic Light Scattering (DLS) and X-ray diffraction (XRD) techniques to determine it diameter, hydrodynamic diameter and crystallinity respectively. Aspect ratio and length of the grown MWCNTs were determined from the HRTEM images with the hydrodynamic diameter using the modified Navier-Stokes and Stokes-Einstein equations. The effect of the prepared MWCNTs dosage were investigated on the Turbidity, Iron (Fe) and Lead (Pb) removal efficiency of coal washery effluent. The MWCNTs with higher length (58.17 μm) and diameter (71 nm) tend to show high turbidity and Fe removal, while MWCNTs with lower length (38.87 μm) and diameter (45 nm) tend to show high removal of Pb. Hence, the growth temperature during CCVD operation shows a great effluence on the aspect ratio of MWCNTs which determines it area of applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation at low speeds of the effect of aspect ratio and sweep on rolling stability derivatives of untapered wings

NASA Technical Reports Server (NTRS)

Goodman, Alex; Fisher, Lewis R.

1949-01-01

A low scale wind tunnel investigation was conducted in rolling flow to determine the effects of aspect ratio and sweep (when varied independently) on the rolling stability derivatives for a series of untapered wings. Test results indicate that when the aspect ratio was held constant, an increase in the sweepback angle caused a significant reduction in the damping in roll at low lift coefficients for only the higher aspect ratios that were tested. This result was in agreement with available swept wing theory which indicated no effect of sweep for aspect ratios near zero. The result of the linear theory that the damping in roll is independent of lift coefficient and that the yawing moment and lateral force due to rolling are directly proportional to the lift coefficient was found to be valid for only a very limited lift coefficient range when the wings were highly swept. For such wings, the damping was found to increase in magnitude and the yawing moment due to rolling, to change from negative to positive at moderate lift coefficients. The effect of wing tip suction, not acounted for by present theory, was found to be very important with regard to the yawing moment due to rolling, particularly for low aspect ratio swept wings. An empirical means of correcting present theory for the effect of tip suction is suggested.

Numerical modeling on air quality in an urban environment with changes of the aspect ratio and wind direction.

PubMed

Yassin, Mohamed F

2013-06-01

Due to heavy traffic emissions within an urban environment, air quality during the last decade becomes worse year by year and hazard to public health. In the present work, numerical modeling of flow and dispersion of gaseous emissions from vehicle exhaust in a street canyon were investigated under changes of the aspect ratio and wind direction. The three-dimensional flow and dispersion of gaseous pollutants were modeled using a computational fluid dynamics (CFD) model which was numerically solved using Reynolds-averaged Navier-Stokes (RANS) equations. The diffusion flow field in the atmospheric boundary layer within the street canyon was studied for different aspect ratios (W/H=1/2, 3/4, and 1) and wind directions (θ=90°, 112.5°, 135°, and 157.5°). The numerical models were validated against wind tunnel results to optimize the turbulence model. The numerical results agreed well with the wind tunnel results. The simulation demonstrated that the minimum concentration at the human respiration height within the street canyon was on the windward side for aspect ratios W/H=1/2 and 1 and wind directions θ=112.5°, 135°, and 157.5°. The pollutant concentration level decreases as the wind direction and aspect ratio increase. The wind velocity and turbulence intensity increase as the aspect ratio and wind direction increase.

Preliminary design characteristics of a subsonic business jet concept employing an aspect ratio 25 strut braced wing

NASA Technical Reports Server (NTRS)

Turriziani, R. V.; Lovell, W. A.; Martin, G. L.; Price, J. E.; Swanson, E. E.; Washburn, G. F.

1980-01-01

The advantages of replacing the conventional wing on a transatlantic business jet with a larger, strut braced wing of aspect ratio 25 were evaluated. The lifting struts reduce both the induced drag and structural weight of the heavier, high aspect ratio wing. Compared to the conventional airplane, the strut braced wing design offers significantly higher lift to drag ratios achieved at higher lift coefficients and, consequently, a combination of lower speeds and higher altitudes. The strut braced wing airplane provides fuel savings with an attendant increase in construction costs.

What makes you think you are conscious? An agnosticist manifesto

PubMed Central

van Leeuwen, Cees

2015-01-01

The qualitative character of consciousness, its “what-it-is-likeness”, is a contested issue, both in philosophy and psychology. I argue that, rather than by conceptual analyses, the status of “what-it-is-likeness” has to be decided by empirical investigation. Pending the outcome, we should maintain an agnostic stance, in order to remove the bias in favor of fictionalism from our study of consciousness,. I illustrate this with the notion of “ownership unity”. People adhere to the belief of a single, unified self as the owner of their experiences, in spite of abundant dis-unities in the informational content of their experience. On one reading, this supports the notion that the unity of experience is no more than a convenient fiction, based on an illusory experience of unity. Cognitive neuroscience is slanted in favor of such understanding, insofar it emphasizes functional specialization and localization. To restore the balance, I present a complementary perspective: the view that the experience of unity is afforded by the intrinsic, multiscale brain dynamics. This approach offers a biological substrate for unity of experience as a regular scenario within certain boundary conditions, as well mechanisms that may let it go astray. PMID:25904857

Experimental and Calculated Characteristics of Several NACA 44-series Wings with Aspect Ratios of 8, 10, and 12 and Taper Ratios of 2.5 and 3.5

NASA Technical Reports Server (NTRS)

Neely, Robert H; Bollech, Thomas V; Westrick, Gertrude C

1947-01-01

The aerodynamic characteristics of seven unswept tapered wings were determined by calculation from two-dimensional data and by wind-tunnel tests in order to demonstrate the accuracy of the calculations and to show some of the effects of aspect ratio, taper ratio, and root thickness-chord ratio. The characteristics were calculated by the usual application of the lifting-line theory which assumes linear section lift curves and also by an application of the theory which allows the use of nonlinear lift curves. A correction to the lift for the effect of chord was made by using the Jones edge-velocity factor. The wings had aspect ratios of 8, 10, and 12, taper ratios of 2.5 and 3.5, and NACA 44-series airfoils.

Anisometric Particle Systems—from Shape Characterization to Suspension Rheology

NASA Astrophysics Data System (ADS)

Gregorová, Eva; Pabst, Willi; Vaněrková, Lucie

2009-06-01

Methods for the characterization of anisometric particle systems are discussed. For prolate particles, the aspect ratio determination via microscopic image analysis is recalled, and aspect ratio distributions as well as shape-size dependences are commented upon. For oblate particles a simple relation is recalled with can be used to determine an average aspect ratio when size distributions are available from two methods, typically from sedimentation analysis and laser diffraction. The connection between particle shape (aspect ratio) and suspension rheology is outlined and it is shown how a generic procedure, based on Brenner's theory, can be applied to predict the intrinsic viscosity when the aspect ratio is known. On the other hand it is shown, how information on the intrinsic viscosity and the critical solids volume fraction can be extracted from experiments, when the measured concentration dependence of the effective suspension viscosity is adequately interpreted (using the Krieger relation for fitting). The examples mentioned in this paper include systems with oblate or prolate ceramic particles (kaolins, pyrophyllite, wollastonite, silicon carbide) as well as (prolate) pharmaceuticals (mesalamine, ibuprofen, nifuroxazide, paracetamol).

Percolation in suspensions of hard nanoparticles: From spheres to needles

NASA Astrophysics Data System (ADS)

Schilling, Tanja; Miller, Mark A.; van der Schoot, Paul

2015-09-01

We investigate geometric percolation and scaling relations in suspensions of nanorods, covering the entire range of aspect ratios from spheres to extremely slender needles. A new version of connectedness percolation theory is introduced and tested against specialised Monte Carlo simulations. The theory accurately predicts percolation thresholds for aspect ratios of rod length to width as low as 10. The percolation threshold for rod-like particles of aspect ratios below 1000 deviates significantly from the inverse aspect ratio scaling prediction, thought to be valid in the limit of infinitely slender rods and often used as a rule of thumb for nanofibres in composite materials. Hence, most fibres that are currently used as fillers in composite materials cannot be regarded as practically infinitely slender for the purposes of percolation theory. Comparing percolation thresholds of hard rods and new benchmark results for ideal rods, we find that i) for large aspect ratios, they differ by a factor that is inversely proportional to the connectivity distance between the hard cores, and ii) they approach the slender rod limit differently.

Camarada in Node 1 / Unity

NASA Image and Video Library

2005-08-06

S114-E-7539 (6 August 2005) --- Astronaut Charles J. Camarda, STS-114 mission specialist, uses a communication system in the Unity node of the International Space Station while Space Shuttle Discovery was docked to the Station.

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

Canavan, G.H.

This note studies the impact of maximizing the stability index rather than minimizing the first strike cost in choosing offensive missile allocations. It does so in the context of a model in which exchanges between vulnerable missile forces are modeled probabilistically, converted into first and second strike costs through approximations to the value target sets at risk, and the stability index is taken to be their ratio. The value of the allocation that minimizes the first strike cost for both attack preferences are derived analytically. The former recovers results derived earlier. The latter leads to an optimum at unity allocationmore » for which the stability index is determined analytically. For values of the attack preference greater than about unity, maximizing the stability index increases the cost of striking first 10--15%. For smaller values of the attack preference, maximizing the index increases the second strike cost a similar amount. Both are stabilizing, so if both sides could be trusted to target on missiles in order to minimize damage to value and maximize stability, the stability index for vulnerable missiles could be increased by about 15%. However, that would increase the cost to the first striker by about 15%. It is unclear why--having decided to strike--he would do so in a way that would increase damage to himself.« less

Fast controller for a unity-power-factor PWM rectifier

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

Eissa, M.O.; Leeb, S.B.; Verghese, G.C.

1996-01-01

This paper presents an analog implementation of a fast controller for a unity-power-factor (UPF) PWM rectifier. The best settling times of many popular controllers for this type of converter are on the order of a few line cycles, corresponding to bandwidths under 20 Hz. The fast controller demonstrated in this paper can exercise control action at a rate comparable to the switching frequency rather than the line frequency. In order to accomplish this while maintaining unity power factor during steady-state operation, the fast controller employs a ripple-feedback cancellation scheme.

Aspect Ratio Model for Radiation-Tolerant Dummy Gate-Assisted n-MOSFET Layout.

PubMed

Lee, Min Su; Lee, Hee Chul

2014-01-01

In order to acquire radiation-tolerant characteristics in integrated circuits, a dummy gate-assisted n-type metal oxide semiconductor field effect transistor (DGA n-MOSFET) layout was adopted. The DGA n-MOSFET has a different channel shape compared with the standard n-MOSFET. The standard n-MOSFET has a rectangular channel shape, whereas the DGA n-MOSFET has an extended rectangular shape at the edge of the source and drain, which affects its aspect ratio. In order to increase its practical use, a new aspect ratio model is proposed for the DGA n-MOSFET and this model is evaluated through three-dimensional simulations and measurements of the fabricated devices. The proposed aspect ratio model for the DGA n-MOSFET exhibits good agreement with the simulation and measurement results.

Aspect Ratio Model for Radiation-Tolerant Dummy Gate-Assisted n-MOSFET Layout

PubMed Central

Lee, Min Su; Lee, Hee Chul

2014-01-01

In order to acquire radiation-tolerant characteristics in integrated circuits, a dummy gate-assisted n-type metal oxide semiconductor field effect transistor (DGA n-MOSFET) layout was adopted. The DGA n-MOSFET has a different channel shape compared with the standard n-MOSFET. The standard n-MOSFET has a rectangular channel shape, whereas the DGA n-MOSFET has an extended rectangular shape at the edge of the source and drain, which affects its aspect ratio. In order to increase its practical use, a new aspect ratio model is proposed for the DGA n-MOSFET and this model is evaluated through three-dimensional simulations and measurements of the fabricated devices. The proposed aspect ratio model for the DGA n-MOSFET exhibits good agreement with the simulation and measurement results. PMID:27350975

Silicon macroporous arrays with high aspect ratio prepared by ICP etching

NASA Astrophysics Data System (ADS)

Wang, Guozheng; Yang, Bingchen; Wang, Ji; Yang, Jikai; Duanmu, Qingduo

2018-02-01

This paper reports on a macroporous silicon arrays with high aspect ratio, the pores of which are of 162, 205, 252, 276μm depths with 6, 10, 15 and 20 μm diameters respectively, prepared by Multiplex Inductively Coupled Plasma (ICP) etching. It was shown that there are very differences in process of high aspect ratio microstructures between the deep pores, a closed structure, and deep trenches, a open structure. The morphology and the aspect ratio dependent etching were analyzed and discussed. The macroporous silicon etched by ICP process yield an uneven, re-entrant, notched and ripples surface within the pores. The main factors effecting on the RIE lag of HARP etching are the passivation cycle time, the pressure of reactive chamber, and the platen power of ICP system.

Effects of aspect ratio on the phase diagram of spheroidal particles

NASA Astrophysics Data System (ADS)

Kutlu, Songul; Haaga, Jason; Rickman, Jeffrey; Gunton, James

Ellipsoidal particles occur in both colloidal and protein science. Models of protein phase transitions based on interacting spheroidal particles can often be more realistic than those based on spherical molecules. One of the interesting questions is how the aspect ratio of spheroidal particles affects the phase diagram. Some results have been obtained in an earlier study by Odriozola (J. Chem. Phys. 136:134505 (2012)). In this poster we present results for the phase diagram of hard spheroids interacting via a quasi-square-well potential, for different aspect ratios. These results are obtained from Monte Carlo simulations using the replica exchange method. We find that the phase diagram, including the crystal phase transition, is sensitive to the choice of aspect ratio. G. Harold and Leila Y. Mathers Foundation.

Indications of suppression of excited Υ states in Pb-Pb collisions at √(s(NN))=2.76 TeV.

PubMed

Chatrchyan, S; Khachatryan, V; Sirunyan, A M; Tumasyan, A; Adam, W; Bergauer, T; Dragicevic, M; Erö, J; Fabjan, C; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kiesenhofer, W; Krammer, M; Liko, D; Mikulec, I; Pernicka, M; Rahbaran, B; Rohringer, H; Schöfbeck, R; Strauss, J; Taurok, A; Teischinger, F; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C-E; Mossolov, V; Shumeiko, N; Suarez Gonzalez, J; Bansal, S; Benucci, L; De Wolf, E A; Janssen, X; Maes, J; Maes, T; Mucibello, L; Ochesanu, S; Roland, B; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Blekman, F; Blyweert, S; D'Hondt, J; Devroede, O; Gonzalez Suarez, R; Kalogeropoulos, A; Maes, M; Van Doninck, W; Van Mulders, P; Van Onsem, G P; Villella, I; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Gay, A P R; Hammad, G H; Hreus, T; Marage, P E; Thomas, L; Vander Velde, C; Vanlaer, P; Adler, V; Cimmino, A; Costantini, S; Grunewald, M; Klein, B; Lellouch, J; Marinov, A; McCartin, J; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Walsh, S; Zaganidis, N; Basegmez, S; Bruno, G; Caudron, J; Ceard, L; Gil, E Cortina; De Favereau De Jeneret, J; Delaere, C; Favart, D; Giammanco, A; Grégoire, G; Hollar, J; Lemaitre, V; Liao, J; Militaru, O; Nuttens, C; Ovyn, S; Pagano, D; Pin, A; Piotrzkowski, K; Schul, N; Beliy, N; Caebergs, T; Daubie, E; Alves, G A; Brito, L; De Jesus Damiao, D; Pol, M E; Souza, M H G; Aldá Júnior, W L; Carvalho, W; Da Costa, E M; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Nogima, H; Oguri, V; Prado Da Silva, W L; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Bernardes, C A; Dias, F A; Fernandez Perez Tomei, T R; Gregores, E M; Lagana, C; Marinho, F; Mercadante, P G; Novaes, S F; Padula, Sandra S; Darmenov, N; Genchev, V; Iaydjiev, P; Piperov, S; Rodozov, M; Stoykova, S; Sultanov, G; Tcholakov, V; Trayanov, R; Dimitrov, A; Hadjiiska, R; Karadzhinova, A; Kozhuharov, V; Litov, L; Mateev, M; Pavlov, B; Petkov, P; Bian, J G; Chen, G M; Chen, H S; Jiang, C H; Liang, D; Liang, S; Meng, X; Tao, J; Wang, J; Wang, J; Wang, X; Wang, Z; Xiao, H; Xu, M; Zang, J; Zhang, Z; Ban, Y; Guo, S; Guo, Y; Li, W; Mao, Y; Qian, S J; Teng, H; Zhu, B; Zou, W; Cabrera, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Sanabria, J C; Godinovic, N; Lelas, D; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Attikis, A; Galanti, M; Mousa, J; Nicolaou, C; Ptochos, F; Razis, P A; Finger, M; Finger, M; Assran, Y; Kamel, A Ellithi; Khalil, S; Mahmoud, M A; Hektor, A; Kadastik, M; Müntel, M; Raidal, M; Rebane, L; Tiko, A; Azzolini, V; Eerola, P; Fedi, G; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Tuominen, E; Tuominiemi, J; Tuovinen, E; Ungaro, D; Wendland, L; Banzuzi, K; Karjalainen, A; Korpela, A; Tuuva, T; Sillou, D; 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Eggert, N; Gibbons, L K; Heltsley, B; Henriksson, K; Hopkins, W; Khukhunaishvili, A; Kreis, B; Kaufman, G Nicolas; Patterson, J R; Puigh, D; Ryd, A; Saelim, M; Salvati, E; Shi, X; Sun, W; Teo, W D; Thom, J; Thompson, J; Vaughan, J; Weng, Y; Winstrom, L; Wittich, P; Biselli, A; Cirino, G; Winn, D; Abdullin, S; Albrow, M; Anderson, J; Apollinari, G; Atac, M; Bakken, J A; Bauerdick, L A T; Beretvas, A; Berryhill, J; Bhat, P C; Bloch, I; Borcherding, F; Burkett, K; Butler, J N; Chetluru, V; Cheung, H W K; Chlebana, F; Cihangir, S; Cooper, W; Eartly, D P; Elvira, V D; Esen, S; Fisk, I; Freeman, J; Gao, Y; Gottschalk, E; Green, D; Gunthoti, K; Gutsche, O; Hanlon, J; Harris, R M; Hirschauer, J; Hooberman, B; Jensen, H; Johnson, M; Joshi, U; Khatiwada, R; Klima, B; Kousouris, K; Kunori, S; Kwan, S; Leonidopoulos, C; Limon, P; Lincoln, D; Lipton, R; Lykken, J; Maeshima, K; Marraffino, J M; Mason, D; McBride, P; Miao, T; Mishra, K; Mrenna, S; Musienko, Y; Newman-Holmes, C; O'Dell, V; Pordes, R; Prokofyev, O; Saoulidou, N; Sexton-Kennedy, E; Sharma, S; Spalding, W J; Spiegel, L; Tan, P; Taylor, L; Tkaczyk, S; Uplegger, L; Vaandering, E W; Vidal, R; Whitmore, J; Wu, W; Yang, F; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Bourilkov, D; Chen, M; Das, S; De Gruttola, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fisher, M; Fu, Y; Furic, I K; Gartner, J; Hugon, J; Kim, B; Konigsberg, J; Korytov, A; Kropivnitskaya, A; Kypreos, T; Low, J F; Matchev, K; Mitselmakher, G; Muniz, L; Prescott, C; Remington, R; Rinkevicius, A; Schmitt, M; Scurlock, B; Sellers, P; Skhirtladze, N; Snowball, M; Wang, D; Yelton, J; Zakaria, M; Gaultney, V; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Adams, T; Askew, A; Bochenek, J; Chen, J; Diamond, B; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prosper, H; Quertenmont, L; Sekmen, S; Veeraraghavan, V; Baarmand, M M; Dorney, B; Guragain, S; Hohlmann, M; Kalakhety, H; Ralich, R; Vodopiyanov, I; Adams, M R; Anghel, I M; Apanasevich, L; Bai, Y; Bazterra, V E; Betts, R R; Callner, J; Cavanaugh, R; Dragoiu, C; Gauthier, L; Gerber, C E; Hofman, D J; Khalatyan, S; Kunde, G J; Lacroix, F; Malek, M; O'Brien, C; Silkworth, C; Silvestre, C; Smoron, A; Strom, D; Varelas, N; Akgun, U; Albayrak, E A; Bilki, B; Clarida, W; Duru, F; Lae, C K; McCliment, E; Merlo, J-P; Mermerkaya, H; Mestvirishvili, A; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Eskew, C; Fehling, D; Giurgiu, G; Gritsan, A V; Guo, Z J; Hu, G; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Whitbeck, A; Baringer, P; Bean, A; Benelli, G; Grachov, O; Kenny Iii, R P; Murray, M; Noonan, D; Sanders, S; Wood, J S; Zhukova, V; Barfuss, A F; Bolton, T; Chakaberia, I; Ivanov, A; Khalil, S; Makouski, M; Maravin, Y; Shrestha, S; Svintradze, I; Wan, Z; Gronberg, J; Lange, D; Wright, D; Baden, A; Boutemeur, M; Eno, S C; Ferencek, D; Gomez, J A; Hadley, N J; Kellogg, R G; Kirn, M; Lu, Y; Mignerey, A C; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; Dutta, V; Everaerts, P; Gomez Ceballos, G; Goncharov, M; Hahn, K A; Harris, P; Kim, Y; Klute, M; Lee, Y-J; Li, W; Loizides, C; Luckey, P D; Ma, T; Nahn, S; Paus, C; Ralph, D; Roland, C; Roland, G; Rudolph, M; Stephans, G S F; Stöckli, F; Sumorok, K; Sung, K; Velicanu, D; Wenger, E A; Xie, S; Yang, M; Yilmaz, Y; Yoon, A S; Zanetti, M; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dudero, P R; Franzoni, G; Gude, A; Haupt, J; Klapoetke, K; Kubota, Y; Mans, J; Pastika, N; Rekovic, V; Rusack, R; Sasseville, M; Singovsky, A; Tambe, N; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Summers, D; Bloom, K; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Godshalk, A; Iashvili, I; Jain, S; Kharchilava, A; Kumar, A; Shipkowski, S P; Smith, K; Zennamo, J; Alverson, G; Barberis, E; Baumgartel, D; Boeriu, O; Chasco, M; Reucroft, S; Swain, J; Trocino, D; Wood, D; Zhang, J; Anastassov, A; Kubik, A; Odell, N; Ofierzynski, R A; Pollack, B; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Brinkerhoff, A; Hildreth, M; Jessop, C; Karmgard, D J; Kolb, J; Kolberg, T; Lannon, K; Luo, W; Lynch, S; Marinelli, N; Morse, D M; Pearson, T; Ruchti, R; Slaunwhite, J; Valls, N; Wayne, M; Ziegler, J; Bylsma, B; Durkin, L S; Gu, J; Hill, C; Killewald, P; Kotov, K; Ling, T Y; Rodenburg, M; Williams, G; Adam, N; Berry, E; Elmer, P; Gerbaudo, D; Halyo, V; Hebda, P; Hunt, A; Jones, J; Laird, E; Lopes Pegna, D; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Quan, X; Safdi, B; Saka, H; Stickland, D; Tully, C; Werner, J S; Zuranski, A; Acosta, J G; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Zatserklyaniy, A; Alagoz, E; Barnes, V E; Bolla, G; Borrello, L; Bortoletto, D; De Mattia, M; Everett, A; Garfinkel, A F; Gutay, L; Hu, Z; Jones, M; Koybasi, O; Kress, M; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Shipsey, I; Silvers, D; Svyatkovskiy, A; Yoo, H D; Zablocki, J; Zheng, Y; Jindal, P; Parashar, N; Boulahouache, C; Ecklund, K M; Geurts, F J M; Padley, B P; Redjimi, R; Roberts, J; Zabel, J; Betchart, B; Bodek, A; Chung, Y S; Covarelli, R; de Barbaro, P; Demina, R; Eshaq, Y; Flacher, H; Garcia-Bellido, A; Goldenzweig, P; Gotra, Y; Han, J; Harel, A; Miner, D C; Orbaker, D; Petrillo, G; Sakumoto, W; Vishnevskiy, D; Zielinski, M; Bhatti, A; Ciesielski, R; Demortier, L; Goulianos, K; Lungu, G; Malik, S; Mesropian, C; Atramentov, O; Barker, A; Duggan, D; Gershtein, Y; Gray, R; Halkiadakis, E; Hidas, D; Hits, D; Lath, A; Panwalkar, S; Patel, R; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Eusebi, R; Flanagan, W; Gilmore, J; Gurrola, A; Kamon, T; Khotilovich, V; Montalvo, R; Osipenkov, I; Pakhotin, Y; Pivarski, J; Safonov, A; Sengupta, S; Tatarinov, A; Toback, D; Weinberger, M; Akchurin, N; Bardak, C; Damgov, J; Jeong, C; Kovitanggoon, K; Lee, S W; Libeiro, T; Mane, P; Roh, Y; Sill, A; Volobouev, I; Wigmans, R; Yazgan, E; Appelt, E; Brownson, E; Engh, D; Florez, C; Gabella, W; Issah, M; Johns, W; Kurt, P; Maguire, C; Melo, A; Sheldon, P; Snook, B; Tuo, S; Velkovska, J; Arenton, M W; Balazs, M; Boutle, S; Cox, B; Francis, B; Goodell, J; Hirosky, R; Ledovskoy, A; Lin, C; Neu, C; Yohay, R; Gollapinni, S; Harr, R; Karchin, P E; Lamichhane, P; Mattson, M; Milstène, C; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Dasu, S; Efron, J; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Herndon, M; Hervé, A; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Mohapatra, A; Palmonari, F; Reeder, D; Ross, I; Savin, A; Smith, W H; Swanson, J; Weinberg, M

2011-07-29

A comparison of the relative yields of Υ resonances in the μ(+)μ(-) decay channel in Pb-Pb and pp collisions at a center-of-mass energy per nucleon pair of 2.76 TeV is performed with data collected with the CMS detector at the LHC. Using muons of transverse momentum above 4  GeV/c and pseudorapidity below 2.4, the double ratio of the Υ(2S) and Υ(3S) excited states to the Υ(1S) ground state in Pb-Pb and pp collisions, [Υ(2S+3S)/Υ(1S)](Pb-Pb)/[Υ(2S+3S)/Υ(1S)](pp), is found to be 0.31(-0.15)(+0.19)(stat)±0.03(syst). The probability to obtain the measured value, or lower, if the true double ratio is unity, is calculated to be less than 1%.

Ecotoxicological impact of pharmaceuticals found in treated wastewaters: study of carbamazepine, clofibric acid, and diclofenac.

PubMed

Ferrari, Benoît; Paxéus, Nicklas; Lo Giudice, Roberto; Pollio, Antonino; Garric, Jeanne

2003-07-01

In four countries (France, Greece, Italy, and Sweden) occurrence in sewage treatment plant (STP) effluents and ecotoxicity of the pharmaceuticals carbamazepine, clofibric acid, and diclofenac were investigated. Bioassays were performed on bacteria, algae, microcrustaceans, and fishes in order to calculate their predicted no-effect concentrations (PNEC) and to perform a first approach of risk characterization. For this aim, risk has been estimated by the predicted environmental concentration/PNEC ratio and the measured environmental concentration/PNEC ratio. First, regarding the PNEC, carbamazepine appears to be the more hazardous compound. Second, even though it is demonstrated that carbamazepine, clofibric acid, and diclofenac have been detected in effluents, only carbamazepine have been detected in all sewage treatment plants with the greatest concentrations. Third, risk quotients greater than unity were calculated only for carbamazepine, suggesting that risk for the water compartment is expected.

Structure-Function Study of Tertiary Amines as Switchable Polarity Solvents

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

Aaron D. Wilson; Frederick F. Stewart

2014-02-01

A series of tertiary amines have been screened for their function as switchable polarity solvents (SPS). The relative ratios of tertiary amine and carbonate species as well as maximum possible concentration were determined through quantitative 1H and 13C NMR spectroscopy. The viscosities of the polar SPS solutions were measured and ranged from near water in dilute systems through to gel formation at high concentrations. The van't Hoff indices for SPS solutions were measured through freezing point depression studies as a proxy for osmotic pressures. A new form of SPS with an amine : carbonate ratio significantly greater than unity hasmore » been identified. Tertiary amines that function as SPS at ambient pressures appear to be limited to molecules with fewer than 12 carbons. The N,N-dimethyl-n-alkylamine structure has been identified as important to the function of an SPS.« less

Pseudorapidity Asymmetry and Centrality Dependence of Charged Hadron Spectra in d+Au collisions at sqrt(sNN) = 200 GeV

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

Adams, J.; Aggarwal, M.M.; Ahammed, Z.

2005-01-12

The pseudorapidity asymmetry and centrality dependence of charged hadron spectra in d+Au collisions at {radical}s{sub NN} = 200 GeV are presented. The charged particle density at mid-rapidity, its pseudorapidity asymmetry and centrality dependence are reasonably reproduced by a Multi-Phase Transport model, by HIJING, and by the latest calculations in a saturation model. Ratios of transverse momentum spectra between backward and forward pseudorapidity are above unity for p{sub T} below 5 GeV/c. The ratio of central to peripheral spectra in d+Au collisions shows enhancement at 2 < p{sub T} < 6 GeV/c, with a larger effect at backward rapidity than forwardmore » rapidity. Our measurements are in qualitative agreement with gluon saturation and in contrast to calculations based on incoherent multiple partonic scatterings.« less

Butterfly-valve inductive orientation detector

NASA Astrophysics Data System (ADS)

Garrett, Steven

1980-04-01

Relative changes of inductance ΔL/L of a single layer coil surrounding a thin electrically conducting disk which can rotate about an axis perpendicular to the coil axis are studied experimentally as a means of measuring angular displacements. ΔL/L is found to be a strong function of disk diameter and is weakly dependent on the ratio of disk thickness to electromagnetic skin depth when this ratio is of the order unity. Values of ΔL/L as a function of disk diameter are given for lead, brass and copper. Detection sensitivities using a resonant tank circuit or an astatic transformer are given in terms of ΔL/L and it is shown that sensitivities of the order of 10-3 to 10-4 deg are practical. Application of this system to the Rayleigh disk and cryogenic environments are emphasized and an expression for the magnetic torque due to detection currents is given.

Amplification of a high-frequency electromagnetic wave by a relativistic plasma

NASA Technical Reports Server (NTRS)

Yoon, Peter H.

1990-01-01

The amplification of a high-frequency transverse electromagnetic wave by a relativistic plasma component, via the synchrotron maser process, is studied. The background plasma that supports the transverse wave is considered to be cold, and the energetic component whose density is much smaller than that of the background component has a loss-cone feature in the perpendicular momentum space and a finite field-aligned drift speed. The ratio of the background plasma frequency squared to the electron gyrofrequency squared is taken to be sufficiently larger than unity. Such a parameter regime is relevant to many space and astrophysical situations. A detailed study of the amplification process is carried out over a wide range of physical parameters including the loss-cone index, the ratio of the electron mass energy to the temperature of the energetic component, the field-aligned drift speed, the normalized density, and the wave propagation angle.

Photo nuclear energy loss term for muon-nucleus interactions based on xi scaling model of QCD

NASA Technical Reports Server (NTRS)

Roychoudhury, R.

1985-01-01

Extensive air showers (EMC) experiments discovered a significant deviation of the ratio of structure functions of iron and deuteron from unity. It was established that the quark parton distribution in nuclei are different from the corresponding distribution in the nucleus. It was examined whether these results have an effect on the calculation of photo nucleus energy loss term for muon-nucleus nuclear interaction. Though the EMC and SLAC data were restricted to rather large q sq region it is expected that the derivation would persist even in the low q sq domain. For the ratio of iron and deuteron structure function a rather naive least square fit of the form R(x) = a + bx was taken and it is assumed that the formula is valid for the whole q sq region the absence of any knowledge of R(x) for small q sq.

Trachoma Rapid Assessments in Unity and Northern Bahr-el-Ghazal States, Southern Sudan

PubMed Central

Robinson, Emily; Kur, Lucia W.; Ndyaba, Aggrey; Lado, Mounir; Shafi, Juma; Kabare, Emmanuel; McClelland, R. Scott; Kolaczinski, Jan H.

2010-01-01

Background Trachoma is thought to be endemic over large parts of Southern Sudan, but empirical evidence is limited. While some areas east of the Nile have been identified as highly endemic, few trachoma surveys have been conducted in the remainder of the country. This study aimed to determine whether trachoma constitutes a problem to public health in Northern Bahr-el-Ghazal and Unity State, both located west of the Nile. Methods and Principal Findings Trachoma rapid assessments (TRA) were conducted between July and September 2009. Seven villages in Northern Bahr-el-Ghazal State and 13 villages in Unity State were surveyed; an average of 50 children (age 1–9 years) and 44 women (age 15 years and above) were examined per village. Samples for analysis using the APTIMA Combo-2 nucleic acid amplification test (NAAT) were collected from participants with active trachoma in eight villages in Unity State. In Northern Bahr-el-Ghazal State, only three children with active trachoma (trachomatous inflammation follicular (TF) and/or trachomatous inflammation intense (TI)) and two women with trichiasis (TT) were found, in two of the seven villages surveyed. In Unity State, trachoma was endemic in all thirteen villages surveyed; the proportion of children with active trachoma ranged from 33% to 75% between villages, while TF in children ranged from 16% to 44%. Between 4% to 51% of examined women showed signs of TT. Samples from active trachoma cases tested using the NAAT were positive for Chlamydia trachomatis infection for 46.6% of children and 19.0% of women. Conclusions Trachoma presents a major problem to public health Unity State, while the disease is of low priority in Northern-Bahr-el-Ghazal State. Implementation of a population-based prevalence survey is now required in Unity State to generate baseline prevalence data so that trachoma interventions can be initiated and monitored over time. PMID:20957205

Trachoma rapid assessments in Unity and Northern Bahr-el-Ghazal States, Southern Sudan.

PubMed

Robinson, Emily; Kur, Lucia W; Ndyaba, Aggrey; Lado, Mounir; Shafi, Juma; Kabare, Emmanuel; McClelland, R Scott; Kolaczinski, Jan H

2010-10-01

Trachoma is thought to be endemic over large parts of Southern Sudan, but empirical evidence is limited. While some areas east of the Nile have been identified as highly endemic, few trachoma surveys have been conducted in the remainder of the country. This study aimed to determine whether trachoma constitutes a problem to public health in Northern Bahr-el-Ghazal and Unity State, both located west of the Nile. Trachoma rapid assessments (TRA) were conducted between July and September 2009. Seven villages in Northern Bahr-el-Ghazal State and 13 villages in Unity State were surveyed; an average of 50 children (age 1-9 years) and 44 women (age 15 years and above) were examined per village. Samples for analysis using the APTIMA Combo-2 nucleic acid amplification test (NAAT) were collected from participants with active trachoma in eight villages in Unity State. In Northern Bahr-el-Ghazal State, only three children with active trachoma (trachomatous inflammation follicular (TF) and/or trachomatous inflammation intense (TI)) and two women with trichiasis (TT) were found, in two of the seven villages surveyed. In Unity State, trachoma was endemic in all thirteen villages surveyed; the proportion of children with active trachoma ranged from 33% to 75% between villages, while TF in children ranged from 16% to 44%. Between 4% to 51% of examined women showed signs of TT. Samples from active trachoma cases tested using the NAAT were positive for Chlamydia trachomatis infection for 46.6% of children and 19.0% of women. Trachoma presents a major problem to public health Unity State, while the disease is of low priority in Northern-Bahr-el-Ghazal State. Implementation of a population-based prevalence survey is now required in Unity State to generate baseline prevalence data so that trachoma interventions can be initiated and monitored over time.

Atrial corrected Fourier amplitude ratios for the scintigraphic quantitation of valvar regurgitation

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

Dae, M.W.; Botvinick, E.H.; O'Connell, J.W.

1984-01-01

Current scintigraphic methods commonly overestimate the degree of valvar regurgitation (VR), and displace normal ratios from unity, owing largely to RA contamination of the RV region of interest in the ''best septal'' LAO projection. The authors developed a method to correct for this overlap, using the Fourier amplitude (AMP) ratio. Amplitude is first ''weighted'' for phase angle using a vectorial sum, to improve assessment in patients (PTS) with contraction abnormalities. RV AMP is then corrected for underestimation by adding the product of mean LAO RA AMP times the difference between RA areas in anterior and LAO projections to the calculatedmore » RV AMP. In 15 PTS with aortic or mitral VR, corrected AMP ratios (CAR) were compared to ratios assessed angiographically and in 12 PTS without VR were compared to uncorrected AMP ratios (UAR), and to stroke volume ratios (SVR) from SV images (SVI), and ED and ES counts data (CT). CAR interobserver agreement was high (R=.97). When VR PTS ranked by CAR as mild (1.3-1.8), moderate (1.9-2.5), or severe (>2.5) were compared to similar chatheterization based ranks, there were no significant differences using the Mann Whitney test for ordinal data. CAR is a simple, objective and reproducible method of quantitating VR. It reduces the error in those without VR, allows sensitive identification of mild VR, and maintains accurate assessment of severe VR.« less

Hydrodynamic Characteristics of Two Low-Drag Supercavitating Hydrofoils

NASA Technical Reports Server (NTRS)

McGehee, John R.; Johnson, Virgil E., Jr.

1959-01-01

An experimental investigation has been conducted in Langley tank no. 2 to determine the hydrodynamic characteristics of two low-drag supercavitating hydrofoils operating in a range of cavitation numbers from 0 to approximately 6. The hydrofoils had aspect ratios of 1 and 3, and the sections were derived by assuming five terms in the vorticity-distribution expansion of the equivalent airfoil. The aspect-ratio-1 hydrofoil was also tested at zero cavitation number with two sets of end plates having depths of 3/8 and 1/4 chords. Zero cavitation number was established by operating the hydrofoils near the water surface so that complete ventilation of the upper surfaces could be obtained. For those depths of submersion where complete ventilation was not obtained through vortex ventilation, two probes were used to introduce air to the upper surfaces of the hydrofoils and to induce complete ventilation. Data were obtained for a range of speeds from 20 to 80 fps, angles of attack from 2 to 20 deg, and ratios of depth of submersion to chord from 0 to 0.85. The experimental results obtained from the aspect-ratio-1 and aspect-ratio-3, five-term hydrofoils were compared with a three-dimensional zero-cavitation-number theory. The theoretical and experimental values of lift and center of pressure for the aspect-ratio-1 hydrofoil were in agreement, within engineering accuracy, for the range of lift coefficients investigated. The theoretical drag coefficients were lower, by a constant amount, than the experimental drag coefficients. The theoretical expressions derived for the lift, drag, and center of pressure of the aspect-ratio-3 hydrofoil were in agreement, within engineering accuracy, with the experimental values. The theoretical and experimental drag coefficients of the aspect-ratio-3 five-term hydrofoil were lower than the theoretical drag coefficients computed for a comparable Tulin-Burkart hydrofoil.

Robinson and Camarda in Node 1 / Unity module

NASA Image and Video Library

2005-07-30

ISS011-E-11357 (30 July 2005) --- Astronauts Stephen K. Robinson and Charles J. Camarda, STS-114 mission specialists, share a light moment while Robinson plays a guitar in the Unity node of the International Space Station.

Wilson in Node 1 Unity

NASA Image and Video Library

2010-04-10

S131-E-008502 (10 April 2010) --- NASA astronaut Stephanie Wilson, STS-131 mission specialist, retrieves a tool from a drawer in the Unity node of the International Space Station while space shuttle Discovery remains docked with the station.

Some applications of the NASTRAN level 16 subsonic flutter analysis capability. [to transport wing and arrow wing

NASA Technical Reports Server (NTRS)

Doggett, R. V., Jr.; Cunningham, H. J.

1976-01-01

The Level 16 flutter analysis capability was applied to an aspect-ratio-6.8 subsonic transport type wing, an aspect-ratio-1.7 arrow wing, and an aspect-ratio-1.3 all movable horizontal tail with a geared elevator. The transport wing and arrow wing results are compared with experimental results obtained in the Langley transonic dynamic tunnel and with other calculated results obtained using subsonic lifting surface (kernel function) unsteady aerodynamic theory.

Method of fabricating a high aspect ratio microstructure

DOEpatents

Warren, John B.

2003-05-06

The present invention is for a method of fabricating a high aspect ratio, freestanding microstructure. The fabrication method modifies the exposure process for SU-8, an negative-acting, ultraviolet-sensitive photoresist used for microfabrication whereby a UV-absorbent glass substrate, chosen for complete absorption of UV radiation at 380 nanometers or less, is coated with a negative photoresist, exposed and developed according to standard practice. This UV absorbent glass enables the fabrication of cylindrical cavities in a negative photoresist microstructures that have aspect ratios of 8:1.

DANSSino: a pilot version of the DANSS neutrino detector

NASA Astrophysics Data System (ADS)

Alekseev, I.; Belov, V.; Brudanin, V.; Danilov, M.; Egorov, V.; Filosofov, D.; Fomina, M.; Hons, Z.; Kobyakin, A.; Medvedev, D.; Mizuk, R.; Novikov, E.; Olshevsky, A.; Rozov, S.; Rumyantseva, N.; Rusinov, V.; Salamatin, A.; Shevchik, Ye.; Shirchenko, M.; Shitov, Yu.; Starostin, A.; Svirida, D.; Tarkovsky, E.; Tikhomirov, I.; Yakushev, E.; Zhitnikov, I.; Zinatulina, D.

2014-07-01

DANSSino is a reduced pilot version of a solid-state detector of reactor antineutrinos (to be created within the DANSS project and installed under the industrial 3 GWth reactor of the Kalinin Nuclear Power Plant—KNPP). Numerous tests performed at a distance of 11 m from the reactor core demonstrate operability of the chosen design and reveal the main sources of the background. In spite of its small size (20 × 20 × 100 cm3), the pilot detector turned out to be quite sensitive to reactor antineutrinos, detecting about 70 IBD events per day with the signal-to-background ratio about unity.

Saturation of the anisoplanatic error in horizontal imaging scenarios

NASA Astrophysics Data System (ADS)

Beck, Jeffrey; Bos, Jeremy P.

2017-09-01

We evaluate the piston-removed anisoplanatic error for smaller apertures imaging over long horizontal paths. Previous works have shown that the piston and tilt compensated anisoplanatic error saturates to values less than one squared radian. Under these conditions the definition of the isoplanatic angle is unclear. These works focused on nadir pointing telescope systems with aperture sizes between five meters and one half meter. We directly extend this work to horizontal imaging scenarios with aperture sizes smaller than one half meter. We assume turbulence is constant along the imaging path and that the ratio of the aperture size to the atmospheric coherence length is on the order of unity.

Potential of lattice Boltzmann to model droplets on chemically stripe-patterned substrates

NASA Astrophysics Data System (ADS)

Patrick Jansen, H.; Sotthewes, K.; Zandvliet, Harold J. W.; Kooij, E. Stefan

2016-01-01

Lattice Boltzmann modelling (LBM) has recently been applied to a range of different wetting situations. Here we demonstrate its potential in representing complex kinetic effects encountered in droplets on chemically stripe-patterned surfaces. An ultimate example of the power of LBM is provided by comparing simulations and experiments of impacting droplets with varying Weber numbers. Also, the shape evolution of droplets is discussed in relation to their final shape. The latter can then be compared to Surface Evolver (SE) results, since under the proper boundary conditions both approaches should yield the same configuration in a static state. During droplet growth in LBM simulations, achieved by increasing the density within the droplet, the contact line initially advances in the direction parallel to the stripes, therewith increasing its aspect ratio. Once the volume becomes too large the droplet starts wetting additional stripes, leading to a lower aspect ratio. The maximum aspect ratio is shown to be a function of the width ratio of the hydrophobic and hydrophilic stripes and also their absolute widths. In the limit of sufficiently large stripe widths the aspect ratio is solely dependent on the relative stripe widths. The maximum droplet aspect ratio in the LBM simulations is compared to SE simulations and results are shown to be in good agreement. Additionally, we also show the ability of LBM to investigate single stripe wetting, enabling determination of the maximum aspect ratio that can be achieved in the limit of negligible hydrophobic stripe width, under the constraint that the stripe widths are large enough such that they are not easily crossed.

Simulation of a pulsatile total artificial heart: Development of a partitioned Fluid Structure Interaction model

NASA Astrophysics Data System (ADS)

Sonntag, Simon J.; Kaufmann, Tim A. S.; Büsen, Martin R.; Laumen, Marco; Linde, Torsten; Schmitz-Rode, Thomas; Steinseifer, Ulrich

2013-04-01

Heart disease is one of the leading causes of death in the world. Due to a shortage in donor organs artificial hearts can be a bridge to transplantation or even serve as a destination therapy for patients with terminal heart insufficiency. A pusher plate driven pulsatile membrane pump, the Total Artificial Heart (TAH) ReinHeart, is currently under development at the Institute of Applied Medical Engineering of RWTH Aachen University.This paper presents the methodology of a fully coupled three-dimensional time-dependent Fluid Structure Interaction (FSI) simulation of the TAH using a commercial partitioned block-Gauss-Seidel coupling package. Partitioned coupling of the incompressible fluid with the slender flexible membrane as well as a high fluid/structure density ratio of about unity led inherently to a deterioration of the stability (‘artificial added mass instability’). The objective was to conduct a stable simulation with high accuracy of the pumping process. In order to achieve stability, a combined resistance and pressure outlet boundary condition as well as the interface artificial compressibility method was applied. An analysis of the contact algorithm and turbulence condition is presented. Independence tests are performed for the structural and the fluid mesh, the time step size and the number of pulse cycles. Because of the large deformation of the fluid domain, a variable mesh stiffness depending on certain mesh properties was specified for the fluid elements. Adaptive remeshing was avoided. Different approaches for the mesh stiffness function are compared with respect to convergence, preservation of mesh topology and mesh quality. The resulting mesh aspect ratios, mesh expansion factors and mesh orthogonalities are evaluated in detail. The membrane motion and flow distribution of the coupled simulations are compared with a top-view recording and stereo Particle Image Velocimetry (PIV) measurements, respectively, of the actual pump.

Neutronic Reactor Structure

DOEpatents

Vernon, H. C.; Weinberg, A. M.

1961-05-30

The neutronic reactor is comprised of a core consisting of natural uranium and heavy water with a K-factor greater than unity. The core is surrounded by a reflector consisting of natural uranium and ordinary water with a Kfactor less than unity. (AEC)

NEUTRONIC REACTOR STRUCTURE

DOEpatents

Weinberg, A.M.; Vernon, H.C.

1961-05-30

A neutronic reactor is described. It has a core consisting of natural uranium and heavy water and having a K-factor greater than unity which is surrounded by a reflector consisting of natural uranium and ordinary water having a Kfactor less than unity.

Williams in Node 1 / Unity module

NASA Image and Video Library

2007-03-01

ISS014-E-15830 (4 March 2007) --- Astronaut Sunita L. Williams, Expedition 14 flight engineer, works with a portion of the Treadmill Vibration Isolation System (TVIS) during in-flight maintenance (IFM) in the Unity node of the International Space Station.

Numerical analysis on effect of aspect ratio of planar solid oxide fuel cell fueled with decomposed ammonia

NASA Astrophysics Data System (ADS)

Tan, Wee Choon; Iwai, Hiroshi; Kishimoto, Masashi; Brus, Grzegorz; Szmyd, Janusz S.; Yoshida, Hideo

2018-04-01

Planar solid oxide fuel cells (SOFCs) with decomposed ammonia are numerically studied to investigate the effect of the cell aspect ratio. The ammonia decomposer is assumed to be located next to the SOFCs, and the heat required for the endothermic decomposition reaction is supplied by the thermal radiation from the SOFCs. Cells with aspect ratios (ratios of the streamwise length to the spanwise width) between 0.130 and 7.68 are provided with the reactants at a constant mass flow rate. A parametric study is conducted by varying the cell temperature and fuel utility factor to investigate their effects on the cell performance in terms of the voltage efficiency. The effect of the heat supply to the ammonia decomposer is also studied. The developed model shows good agreement, in terms of the current-voltage curve, with the experimental data obtained from a short stack without parameter tuning. The simulation study reveals that the cell with the highest aspect ratio achieves the highest performance under furnace operation. On the other hand, the 0.750 aspect ratio cell with the highest voltage efficiency of 0.67 is capable of thermally sustaining the ammonia decomposers at a fuel utility of 0.80 using the thermal radiation from both sidewalls.

Haze aerosols in the atmosphere of early Earth: manna from heaven.

PubMed

Trainer, Melissa G; Pavlov, Alexander A; Curtis, Daniel B; McKay, Christopher P; Worsnop, Douglas R; Delia, Alice E; Toohey, Darin W; Toon, Owen B; Tolbert, Margaret A

2004-01-01

An organic haze layer in the upper atmosphere of Titan plays a crucial role in the atmospheric composition and climate of that moon. Such a haze layer may also have existed on the early Earth, providing an ultraviolet shield for greenhouse gases needed to warm the planet enough for life to arise and evolve. Despite the implications of such a haze layer, little is known about the organic material produced under early Earth conditions when both CO(2) and CH(4) may have been abundant in the atmosphere. For the first time, we experimentally demonstrate that organic haze can be generated in different CH(4)/CO(2) ratios. Here, we show that haze aerosols are able to form at CH(4) mixing ratios of 1,000 ppmv, a level likely to be present on early Earth. In addition, we find that organic hazes will form at C/O ratios as low as 0.6, which is lower than the predicted value of unity. We also show that as the C/O ratio decreases, the organic particles produced are more oxidized and contain biologically labile compounds. After life arose, the haze may thus have provided food for biota.

Biogas reforming over multi walled carbon nanotubes with Co-Mo/MgO nanoparticles

NASA Astrophysics Data System (ADS)

Khavarian, Mehrnoush; Mohamed, Abdul Rahman

2017-12-01

The utilization of biogas for the production of valuable chemicals is among the very important processes in the energy research field. The most suitable process for biogas reforming is dry reforming of methane. An obvious drawback is the variable composition of biogas rather than the stoichiometrically equimolar quantities of methane and carbon dioxide. Moreover, activating the methane and carbon dioxide molecules in the reforming reaction provides many challenges in exploring new concepts and opportunities for development of unique catalysts. In the present work, the catalytic activity behavior of Co-Mo-MgO/multi-walled carbon nanotubes (MWCNTs) nanocomposite in dry reforming was investigated with different CO2/CH4 feed ratio to evaluate the performance of this catalyst for biogas reforming reaction. It was found that conversions of methane and carbon dioxide were greatly influenced by the feed gas ratio. The CH4 and CO2 conversions are 83 % and 87 % at the reaction temperature of 825 °C, GHSV of 175 L/h.gcat and CO2/CH4 feed ratio of unity. The minimum carbon deposition rate is observed at the CO2/CH4 feed ratio of 0.6 which is 0.080 gc/gcat-h.

Breakthrough during air sampling with polyurethane foam: What do PUF 2/PUF 1 ratios mean?

PubMed

Bidleman, Terry F; Tysklind, Mats

2018-02-01

Frontal chromatography theory is applied to describe movement of gaseous semivolatile organic compounds (SVOCs) through a column of polyurethane foam (PUF). Collected mass fractions (F C ) are predicted for sample volume/breakthrough volume ratios (τ = V S /V B ) up to 6.0 and PUF bed theoretical plate numbers (N) from 2 to 16. The predictions assume constant air concentrations and temperatures. Extension of the calculations is done to relate the collection efficiency of a 2-PUF train (F C1+2 ) to the PUF 2/PUF 1 ratio. F C1+2 exceeds 0.9 for PUF 2/PUF 1 ≤ 0.5 and lengths of PUF commonly used in air samplers. As the PUF 2/PUF 1 ratio approaches unity, confidence in these predictions is limited by the analytical ability to distinguish residues on the two PUFs. Field data should not be arbitrarily discarded because some analytes broke through to the backup PUF trap. The fractional collection efficiencies can be used to estimate air concentrations from quantities retained on the PUF trap when sampling is not quantitative. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultra-high aspect ratio replaceable AFM tips using deformation-suppressed focused ion beam milling.

PubMed

Savenko, Alexey; Yildiz, Izzet; Petersen, Dirch Hjorth; Bøggild, Peter; Bartenwerfer, Malte; Krohs, Florian; Oliva, Maria; Harzendorf, Torsten

2013-11-22

Fabrication of ultra-high aspect ratio exchangeable and customizable tips for atomic force microscopy (AFM) using lateral focused ion beam (FIB) milling is presented. While on-axis FIB milling does allow high aspect ratio (HAR) AFM tips to be defined, lateral milling gives far better flexibility in terms of defining the shape and size of the tip. Due to beam-induced deformation, it has so far not been possible to define HAR structures using lateral FIB milling. In this work we obtain aspect ratios of up to 45, with tip diameters down to 9 nm, by a deformation-suppressing writing strategy. Several FIB milling strategies for obtaining sharper tips are discussed. Finally, assembly of the HAR tips on a custom-designed probe as well as the first AFM scanning is shown.

Energy and Economic Trade Offs for Advanced Technology Subsonic Aircraft

NASA Technical Reports Server (NTRS)

Maddalon, D. V.; Wagner, R. D.

1976-01-01

Changes in future aircraft technology which conserve energy are studied, along with the effect of these changes on economic performance. Among the new technologies considered are laminar-flow control, composite materials with and without laminar-flow control, and advanced airfoils. Aircraft design features studied include high-aspect-ratio wings, thickness ratio, and range. Engine technology is held constant at the JT9D level. It is concluded that wing aspect ratios of future aircraft are likely to significantly increase as a result of new technology and the push of higher fuel prices. Composite materials may raise aspect radio to about 11 to 12 and practical laminar flow-control systems may further increase aspect ratio to 14 or more. Advanced technology provides significant reductions in aircraft take-off gross weight, energy consumption, and direct operating cost.

Global two-fluid simulations of geodesic acoustic modes in strongly shaped tight aspect ratio tokamak plasmas

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

Robinson, J. R.; Hnat, B.; Thyagaraja, A.

2013-05-15

Following recent observations suggesting the presence of the geodesic acoustic mode (GAM) in ohmically heated discharges in the Mega Amp Spherical Tokamak (MAST) [J. R. Robinson et al., Plasma Phys. Controlled Fusion 54, 105007 (2012)], the behaviour of the GAM is studied numerically using the two fluid, global code CENTORI [P. J. Knight et al. Comput. Phys. Commun. 183, 2346 (2012)]. We examine mode localisation and effects of magnetic geometry, given by aspect ratio, elongation, and safety factor, on the observed frequency of the mode. An excellent agreement between simulations and experimental data is found for simulation plasma parameters matchedmore » to those of MAST. Increasing aspect ratio yields good agreement between the GAM frequency found in the simulations and an analytical result obtained for elongated large aspect ratio plasmas.« less

Cryogenic Etching of High Aspect Ratio 400 nm Pitch Silicon Gratings.

PubMed

Miao, Houxun; Chen, Lei; Mirzaeimoghri, Mona; Kasica, Richard; Wen, Han

2016-10-01

The cryogenic process and Bosch process are two widely used processes for reactive ion etching of high aspect ratio silicon structures. This paper focuses on the cryogenic deep etching of 400 nm pitch silicon gratings with various etching mask materials including polymer, Cr, SiO 2 and Cr-on-polymer. The undercut is found to be the key factor limiting the achievable aspect ratio for the direct hard masks of Cr and SiO 2 , while the etch selectivity responds to the limitation of the polymer mask. The Cr-on-polymer mask provides the same high selectivity as Cr and reduces the excessive undercut introduced by direct hard masks. By optimizing the etching parameters, we etched a 400 nm pitch grating to ≈ 10.6 μ m depth, corresponding to an aspect ratio of ≈ 53.

Collapse of elongated voids in porous energetic materials: Effects of void orientation and aspect ratio on initiation

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Schmidt, Martin J.; Udaykumar, H. S.

2017-04-01

The sensitivity of porous energetic materials depends on mesostructural heterogeneities such as voids, defects, cracks, and grain boundaries. The mesostructure of pressed explosives contains voids of arbitrary shapes including elongated voids of various orientations and aspect ratios. Mesoscale simulations to date have analyzed the effect of void morphology on the sensitivity of energetic materials for idealized shapes such as cylindrical, conical, and elliptical. This work analyzes the sensitivity behavior of elongated voids in an HMX matrix subject to shock loading. Simulations show that sensitivity of elongated voids depends strongly on orientation as well as aspect ratio. Ranges of orientations and aspects ratios are identified that enhance or inhibit initiation. Insights obtained from single elongated void analyses are used to identify sensitive locations in an imaged mesostructure of a pressed explosive sample.

Short revolving wings enable hovering animals to avoid stall and reduce drag

NASA Astrophysics Data System (ADS)

Lentink, David; Kruyt, Jan W.; Heijst, Gertjan F.; Altshuler, Douglas L.

2014-11-01

Long and slender wings reduce the drag of airplanes, helicopters, and gliding animals, which operate at low angle of attack (incidence). Remarkably, there is no evidence for such influence of wing aspect ratio on the energetics of hovering animals that operate their wings at much higher incidence. High incidence causes aircraft wings to stall, hovering animals avoid stall by generating an attached vortex along the leading edge of their wings that elevates lift. Hypotheses that explain this capability include the necessity for a short radial distance between the shoulder joint and wing tip, measured in chord lengths, instead of the long tip-to-tip distance that elevates aircraft performance. This stems from how hovering animals revolve their wings around a joint, a condition for which the precise effect of aspect ratio on stall performance is unknown. Here we show that the attachment of the leading edge vortex is determined by wing aspect ratio with respect to the center of rotation-for a suite of aspect ratios that represent both animal and aircraft wings. The vortex remains attached when the local radius is shorter than 4 chord lengths, and separates outboard on more slender wings. Like most other hovering animals, hummingbirds have wing aspect ratios between 3 and 4, much stubbier than helicopters. Our results show this makes their wings robust against flow separation, which reduces drag below values obtained with more slender wings. This revises our understanding of how aspect ratio improves performance at low Reynolds numbers.

The challenge of promoting professionalism through medical ethics and humanities education.

PubMed

Doukas, David J; McCullough, Laurence B; Wear, Stephen; Lehmann, Lisa S; Nixon, Lois LaCivita; Carrese, Joseph A; Shapiro, Johanna F; Green, Michael J; Kirch, Darrell G

2013-11-01

Given recent emphasis on professionalism training in medical schools by accrediting organizations, medical ethics and humanities educators need to develop a comprehensive understanding of this emphasis. To achieve this, the Project to Rebalance and Integrate Medical Education (PRIME) II Workshop (May 2011) enlisted representatives of the three major accreditation organizations to join with a national expert panel of medical educators in ethics, history, literature, and the visual arts. PRIME II faculty engaged in a dialogue on the future of professionalism in medical education. The authors present three overarching themes that resulted from the PRIME II discussions: transformation, question everything, and unity of vision and purpose.The first theme highlights that education toward professionalism requires transformational change, whereby medical ethics and humanities educators would make explicit the centrality of professionalism to the formation of physicians. The second theme emphasizes that the flourishing of professionalism must be based on first addressing the dysfunctional aspects of the current system of health care delivery and financing that undermine the goals of medical education. The third theme focuses on how ethics and humanities educators must have unity of vision and purpose in order to collaborate and identify how their disciplines advance professionalism. These themes should help shape discussions of the future of medical ethics and humanities teaching.The authors argue that improvement of the ethics and humanities-based knowledge, skills, and conduct that fosters professionalism should enhance patient care and be evaluated for its distinctive contributions to educational processes aimed at producing this outcome.

Cosmological Evolution of Massive Black Holes: Effects of Eddington Ratio Distribution and Quasar Lifetime

NASA Astrophysics Data System (ADS)

Cao, Xinwu

2010-12-01

A power-law time-dependent light curve for active galactic nuclei (AGNs) is expected by the self-regulated black hole growth scenario, in which the feedback of AGNs expels gas and shut down accretion. This is also supported by the observed power-law Eddington ratio distribution of AGNs. At high redshifts, the AGN life timescale is comparable with (or even shorter than) the age of the universe, which sets a constraint on the minimal Eddington ratio for AGNs on the assumption of a power-law AGN light curve. The black hole mass function (BHMF) of AGN relics is calculated by integrating the continuity equation of massive black hole number density on the assumption of the growth of massive black holes being dominated by mass accretion with a power-law Eddington ratio distribution for AGNs. The derived BHMF of AGN relics at z = 0 can fit the measured local mass function of the massive black holes in galaxies quite well, provided the radiative efficiency ~0.1 and a suitable power-law index for the Eddington ratio distribution are adopted. In our calculations of the black hole evolution, the duty cycle of AGN should be less than unity, which requires the quasar life timescale τQ >~ 5 × 108 years.

Stable-isotope studies of rocks and secondary minerals in a vapor-dominated hydrothermal system at The Geysers, Sonoma County, California

NASA Astrophysics Data System (ADS)

Lambert, Steven J.; Epstein, Samuel

1992-11-01

The Geysers, a vapor-dominated hydrothermal system, is developed in host rock of the Franciscan Formation, which contains veins of quartz and calcite whose δ 18O values record the temperatures and isotopic compositions of fluids prevailing during at least two different episodes of rock-fluid interaction. The first episode took place at about 200°C, during which marine silica and carbonate apparently interacted with ocean water entrapped in the sediments to form veins of quartz and calcite whose δ 18O values were around +19 and +16%, respectively. The calculated water/mineral ratios were less than unity. The water may have profoundly influenced the δ 18O values of spilitic basalts during their metamorphism to greenstones. Serpentinization and structural emplacement of ophiolite slabs were isotopically unrelated to this episode, which was essentially a low-grade (post-Cretaceous?) burial metamorphism. D/H ratios of actinolite, chlorite, and micas in host rocks were more profoundly altered during this episode than were 18O/ 16O ratios. A paleogeothermal gradient of about 53°C/km has been inferred for this episode, from δ 18O-depth distributions of vein minerals. The second episode, in part recorded by cogenetic vein quartz and calcite δ 18O values of +4 to +6% and +1 to +3%, respectively, began with large quantities of meteoric water circulating in fractures in the rock at temperatures of 160-180°C in response to the initiation of the Pliocene-Pleistocene Clear Lake magmatism. The temperature rose, and with the restricted circulation of fluids the ancestral hot-water system evolved into the presently active vapor-dominated system, which according to the cogenetic vein quartz and calcite δ 18O values involved temperatures as high as 320°C and fluid/mineral ratios near unity. The change in the oxygen-isotopic composition of the serpentinite within the host rock during this later activity was negligible. The δ 13C values of vein calcite at The Geysers reflect both a marine carbonate and organic component of carbon, but carbon-isotope exchange has been facilitated by the vapor-dominated hydrothermal fluid to a greater degree than in any other episode or in other hot-water systems.

Auxiliary drying to prevent pattern collapse in high aspect ratio nanostructures

NASA Astrophysics Data System (ADS)

Liu, Gang; Zhou, Jie; Xiong, Ying; Zhang, Xiaobo; Tian, Yangchao

2011-07-01

Many defects are generated in densely packed high aspect ratio structures during nanofabrication. Pattern collapse is one of the serious problems that may arise, mainly due to the capillary force during drying after the rinsing process. In this paper, a method of auxiliary drying is presented to prevent pattern collapse in high aspect ratio nanostructures by adding an auxiliary substrate as a reinforcing rib to restrict deformation and to balance the capillary force. The principle of the method is presented based on the analysis of pattern collapse. A finite element method is then applied to analyze the deformation of the resist beams caused by the surface tension using the ANSYS software, and the effect of the nanostructure's length to width ratio simulated and analyzed. Finally, the possible range of applications based on the proposed method is discussed. Our results show that the aspect ratio may be increased 2.6 times without pattern collapse; furthermore, this method can be widely used in the removal of solvents in micro- and nanofabrication.

Auxiliary drying to prevent pattern collapse in high aspect ratio nanostructures.

PubMed

Liu, Gang; Zhou, Jie; Xiong, Ying; Zhang, Xiaobo; Tian, Yangchao

2011-07-29

Many defects are generated in densely packed high aspect ratio structures during nanofabrication. Pattern collapse is one of the serious problems that may arise, mainly due to the capillary force during drying after the rinsing process. In this paper, a method of auxiliary drying is presented to prevent pattern collapse in high aspect ratio nanostructures by adding an auxiliary substrate as a reinforcing rib to restrict deformation and to balance the capillary force. The principle of the method is presented based on the analysis of pattern collapse. A finite element method is then applied to analyze the deformation of the resist beams caused by the surface tension using the ANSYS software, and the effect of the nanostructure's length to width ratio simulated and analyzed. Finally, the possible range of applications based on the proposed method is discussed. Our results show that the aspect ratio may be increased 2.6 times without pattern collapse; furthermore, this method can be widely used in the removal of solvents in micro- and nanofabrication.

Reiter conducts EVA tool config in Node 1 / Unity module

NASA Image and Video Library

2006-11-16

ISS014-E-08055 (16 Nov. 2006) --- European Space Agency (ESA) astronaut Thomas Reiter, Expedition 14 flight engineer, takes inventory of hardware during an Information Management System (IMS) update in the Unity node of the International Space Station.

Near-Unity Absorption in van der Waals Semiconductors for Ultrathin Optoelectronics.

PubMed

Jariwala, Deep; Davoyan, Artur R; Tagliabue, Giulia; Sherrott, Michelle C; Wong, Joeson; Atwater, Harry A

2016-09-14

We demonstrate near-unity, broadband absorbing optoelectronic devices using sub-15 nm thick transition metal dichalcogenides (TMDCs) of molybdenum and tungsten as van der Waals semiconductor active layers. Specifically, we report that near-unity light absorption is possible in extremely thin (<15 nm) van der Waals semiconductor structures by coupling to strongly damped optical modes of semiconductor/metal heterostructures. We further fabricate Schottky junction devices using these highly absorbing heterostructures and characterize their optoelectronic performance. Our work addresses one of the key criteria to enable TMDCs as potential candidates to achieve high optoelectronic efficiency.

Simultaneous shape repulsion and global assimilation in the perception of aspect ratio

PubMed Central

Sweeny, Timothy D.; Grabowecky, Marcia; Suzuki, Satoru

2012-01-01

Although local interactions involving orientation and spatial frequency are well understood, less is known about spatial interactions involving higher level pattern features. We examined interactive coding of aspect ratio, a prevalent two-dimensional feature. We measured perception of two simultaneously flashed ellipses by randomly post-cueing one of them and having observers indicate its aspect ratio. Aspect ratios interacted in two ways. One manifested as an aspect-ratio-repulsion effect. For example, when a slightly tall ellipse and a taller ellipse were simultaneously flashed, the less tall ellipse appeared flatter and the taller ellipse appeared even taller. This repulsive interaction was long range, occurring even when the ellipses were presented in different visual hemifields. The other interaction manifested as a global assimilation effect. An ellipse appeared taller when it was a part of a global vertical organization than when it was a part of a global horizontal organization. The repulsion and assimilation effects temporally dissociated as the former slightly strengthened, and the latter disappeared when the ellipse-to-mask stimulus onset asynchrony was increased from 40 to 140 ms. These results are consistent with the idea that shape perception emerges from rapid lateral and hierarchical neural interactions. PMID:21248223

Fabrication of ultra-high aspect ratio (>160:1) silicon nanostructures by using Au metal assisted chemical etching

NASA Astrophysics Data System (ADS)

Li, Hailiang; Ye, Tianchun; Shi, Lina; Xie, Changqing

2017-12-01

We present a facile and effective approach for fabricating high aspect ratio, dense and vertical silicon nanopillar arrays, using a combination of metal etching following electron-beam lithography and Au metal assisted chemical etching (MacEtch). Ti/Au nanostructures used as catalysts in MacEtch are formed by single layer resist-based electron-beam exposure followed by ion beam etching. The effects of MacEtch process parameters, including half period, etching time, the concentrations of H2O2 and HF, etching temperature and drying method are systematically investigated. Especially, we demonstrate an enhancement of etching quality by employing cold MacEtch process, and an enhancement in preventing the collapse of high aspect ratio nanostructures by employing low surface tension rinse liquid and natural evaporation in the drying stage. Using an optimized MacEtch process, vertical silicon nanopillar arrays with a period of 250 nm and aspect ratio up to 160:1 are realized. Our results should be instructive for exploring the achievable aspect ratio limit in silicon nanostructures and may find potential applications in photovoltaic devices, thermoelectric devices and x-ray diffractive optics.

Preparation of HCPT-Loaded Nanoneedles with Pointed Ends for Highly Efficient Cancer Chemotherapy

NASA Astrophysics Data System (ADS)

Wu, Shichao; Yang, Xiangrui; Li, Yang; Wu, Hongjie; Huang, Yu; Xie, Liya; Zhang, Ying; Hou, Zhenqing; Liu, Xiangyang

2016-06-01

The high-aspect-ratio nanoparticles were proved to be internalized much more rapidly and efficiently by cancer cells than the nanoparticles with an equal aspect ratio. Herein, a kind of high-aspect ratio, pointed-end nanoneedles (NDs) with a high drug loading (15.04 %) and the prolonged drug release profile were fabricated with an anti-tumor drug—10-hydroxycamptothecin (HCPT)—via an ultrasound-assisted emulsion crystallization technique. It is surprising to see that the cellular internalization of NDs with an average length of 5 μm and an aspect ratio of about 12:1 was even much faster and higher than that of nanorods with the same size and the nanospheres with a much smaller size of 150 nm. The results further validated that cellular internalization of the nanoparticles exhibited a strong shape-dependent effect, and cellular uptake may favor the particles with sharp ends as well as a high-aspect ratio instead of particle size. The NDs with enhanced cytotoxicity would lead to a promising sustained local drug delivery system for highly efficient anticancer therapy. More importantly, the fabrication of NDs opens a door to design new formulations of nanoneedle drug delivery systems for highly efficient cancer.

An effective medium approach to modelling the pressure-dependent electrical properties of porous rocks

NASA Astrophysics Data System (ADS)

Han, Tongcheng

2018-07-01

Understanding the electrical properties of rocks under varying pressure is important for a variety of geophysical applications. This study proposes an approach to modelling the pressure-dependent electrical properties of porous rocks based on an effective medium model. The so-named Textural model uses the aspect ratios and pressure-dependent volume fractions of the pores and the aspect ratio and electrical conductivity of the matrix grains. The pores were represented by randomly oriented stiff and compliant spheroidal shapes with constant aspect ratios, and their pressure-dependent volume fractions were inverted from the measured variation of total porosity with differential pressure using a dual porosity model. The unknown constant stiff and compliant pore aspect ratios and the aspect ratio and electrical conductivity of the matrix grains were inverted by best fitting the modelled electrical formation factor to the measured data. Application of the approach to three sandstone samples covering a broad porosity range showed that the pressure-dependent electrical properties can be satisfactorily modelled by the proposed approach. The results demonstrate that the dual porosity concept is sufficient to explain the electrical properties of porous rocks under pressure through the effective medium model scheme.

Conversion from dose-to-graphite to dose-to-water in an 80 MeV/A carbon ion beam.

PubMed

Rossomme, S; Palmans, H; Shipley, D; Thomas, R; Lee, N; Romano, F; Cirrone, P; Cuttone, G; Bertrand, D; Vynckier, S

2013-08-21

Based on experiments and numerical simulations, a study is carried out pertaining to the conversion of dose-to-graphite to dose-to-water in a carbon ion beam. This conversion is needed to establish graphite calorimeters as primary standards of absorbed dose in these beams. It is governed by the water-to-graphite mass collision stopping power ratio and fluence correction factors, which depend on the particle fluence distributions in each of the two media. The paper focuses on the experimental and numerical determination of this fluence correction factor for an 80 MeV/A carbon ion beam. Measurements have been performed in the nuclear physics laboratory INFN-LNS in Catania (Sicily, Italy). The numerical simulations have been made with a Geant4 Monte Carlo code through the GATE simulation platform. The experimental data are in good agreement with the simulated results for the fluence correction factors and are found to be close to unity. The experimental values increase with depth reaching 1.010 before the Bragg peak region. They have been determined with an uncertainty of 0.25%. Different numerical results are obtained depending on the level of approximation made in calculating the fluence correction factors. When considering carbon ions only, the difference between measured and calculated values is maximal just before the Bragg peak, but its value is less than 1.005. The numerical value is close to unity at the surface and increases to 1.005 near the Bragg peak. When the fluence of all charged particles is considered, the fluence correction factors are lower than unity at the surface and increase with depth up to 1.025 before the Bragg peak. Besides carbon ions, secondary particles created due to nuclear interactions have to be included in the analysis: boron ions ((10)B and (11)B), beryllium ions ((7)Be), alpha particles and protons. At the conclusion of this work, we have the conversion of dose-to-graphite to dose-to-water to apply to the response of a graphite calorimeter in an 80 MeV/A carbon ion beam. This conversion consists of the product of two contributions: the water-to-graphite electronic mass collision stopping power ratio, which is equal to 1.115, and the fluence correction factor which varies linearly with depth, as k(fl, all) = 0.9995 + 0.0048(zw-eq). The latter has been determined on the basis of experiments and numerical simulations.

Theoretical Prediction of Pressure Distributions on Nonlifting Airfoils at High Subsonic Speeds

NASA Technical Reports Server (NTRS)

Spreiter, John R; Alksne, Alberta

1955-01-01

Theoretical pressure distributions on nonlifting circular-arc airfoils in two-dimensional flows with high subsonic free-stream velocity are found by determining approximate solutions, through an iteration process, of an integral equation for transonic flow proposed by Oswatitsch. The integral equation stems directly from the small-disturbance theory for transonic flow. This method of analysis possesses the advantage of remaining in the physical, rather than the hodograph, variable and can be applied in airfoils having curved surfaces. After discussion of the derivation of the integral equation and qualitative aspects of the solution, results of calculations carried out for circular-arc airfoils in flows with free-stream Mach numbers up to unity are described. These results indicate most of the principal phenomena observed in experimental studies.

Psychiatrists and Their Role in an Integrative Approach to Sexual Problems.

PubMed

Raisi, Firoozeh; Yahyavi, Seyyed Taha

2015-03-01

Sexuality is a unit part of humans that has been evaluated as several fragmented particles for years. Although many biomedical and psychosocial approaches have been developed in the field of sex, these approaches usually have not been led to the complete satisfaction of the patients. It seems that for a comprehensive evaluation and management of the sexual problems, the unity of sex should be respected and the biopsychosocial multilayer aspects of the sex should be apprehended. Psychiatry is a unique point that both biomedical and psychosocial sciences reach each other. Therefore, psychiatrists should play a critical role as a modulator in the multidisciplinary team for management of the sexual problems. In this regard, comprehensive training of psychiatrists is highly recommended. One of the primary steps could be developing the psychosexual fellowship.

Unifying relations for scattering amplitudes

NASA Astrophysics Data System (ADS)

Cheung, Clifford; Shen, Chia-Hsien; Wen, Congkao

2018-02-01

We derive new amplitudes relations revealing a hidden unity among a wideranging variety of theories in arbitrary spacetime dimensions. Our results rely on a set of Lorentz invariant differential operators which transmute physical tree-level scattering amplitudes into new ones. By transmuting the amplitudes of gravity coupled to a dilaton and two-form, we generate all the amplitudes of Einstein-Yang-Mills theory, Dirac-Born-Infield theory, special Galileon, nonlinear sigma model, and biadjoint scalar theory. Transmutation also relates amplitudes in string theory and its variants. As a corollary, celebrated aspects of gluon and graviton scattering like color-kinematics duality, the KLT relations, and the CHY construction are inherited traits of the transmuted amplitudes. Transmutation recasts the Adler zero as a trivial consequence of the Weinberg soft theorem and implies new subleading soft theorems for certain scalar theories.

Bolide impacts and the oxidation state of carbon in the earth's early atmosphere

NASA Technical Reports Server (NTRS)

Kasting, James F.

1990-01-01

A one-dimensional photochemical model was used to examine the effect of bolide impacts on the oxidation state of earth's primitive atmosphere. The impact rate should have been high prior to 3.8 Ga before present, based on evidence derived from the moon. Impacts of comets or carbonaceous asteroids should have enhanced the atmospheric CO/CO2 ratio by bringing in CO ice and/or organic carbon that can be oxidized to CO in the impact plume. Ordinary chondritic impactors would contain elemental iron that could have reacted with ambient CO2 to give CO. Nitric oxide (NO) should also have been produced by reaction between ambient CO2 and N2 in the hot impact plumes. High NO concentrations increase the atmospheric CO/CO2 ratio by increasing the rainout rate of oxidized gases. According to the model, atmospheric CO/CO2 ratios of unity or greater are possible during the first several hundred million years of earth's history, provided that dissolved CO was not rapidly oxidized to bicarbonate in the ocean.

Effects of Mean Flow Profiles on the Instability of a Low-Density Gas Jet Injected into a High-Density Gas

NASA Technical Reports Server (NTRS)

Vedantam, NandaKishore; Parthasarathy, Ramkumar N.

2004-01-01

The effects of the mean velocity profiles on the instability characteristics in the near-injector region of axisymmetric low density gas jets injected vertically upwards into a high-density gas medium were investigated using linear inviscid stability analysis. The flow was assumed to be isothermal and locally parallel. Three velocity profiles, signifying different changes in the mean velocity in the shear layer, were used in the analysis. The effects of the inhomogeneous shear layer and the Froude number (signifying the effects of gravity) on the instability for each set of mean profiles were delineated. At a large Froude number (negligible gravity), a critical density ratio was found for the three profiles at which the jet became absolutely unstable. The critical density ratio for each velocity profile was increased as the Froude number was reduced. A critical Froude number was found for the three sets of profiles, below which the jet was absolutely unstable for all the density ratios less than unity, which demarcated the jet flow into the momentum-driven regime and the buoyancy-driven regime.

The anomalous C 4 intensity ratio in symbiotic stars

NASA Technical Reports Server (NTRS)

Michalitsianos, A. G.; Kafatos, M.; Fahey, R. P.

1988-01-01

The C IV lambda lambda 1548.2,1550.8 resonance doublet in a symbiotic stars was shown to exhibit anomalous line intensity ratios in which I (lambda 1548.2)/I(lambda 1550.8) less than 1, or less than the optically-thick limit of unity. The R Aquarii-central HII region and RX Puppis exhibit this phenomena. The I(lambda 1548.2)/I(lambda 1550.8) ratio in RX Puppis is found to vary inversely with the total C IV line intensity, and with the FES-visual light, as the object declined over a 5 yr period following a brightening in UV and optical emission which peaked in 1982. This doublet intensity behavior could be explained by a wind which has a narrow velocity range of 600 approx. less than sup v wind approx. less than 1000 km/sec, or by the pumping of the Fe II (mul. 45.01) transition a sup 4 F sub 9/2 - y sup 4 H(o) sub 11/2 by C IV lambda 1548.2, which effectively scatters C IV photons into the Fe II spectrum in these objects.

Spontaneous emission in dielectric nanoparticles

NASA Astrophysics Data System (ADS)

Pukhov, K. K.; Basiev, T. T.; Orlovskii, Yu. V.

2008-09-01

An analytical expression is obtained for the radiative-decay rate of an excited optical center in an ellipsoidal dielectric nanoparticle (with sizes much less than the wavelength) surrounded by a dielectric medium. It is found that the ratio of the decay rate A nano of an excited optical center in the nanoparticle to the decay rate A bulk of an excited optical center in the bulk sample is independent of the local-field correction and, therefore, of the adopted local-field model. Moreover, the expression implies that the ratio A nano/ A bulk for oblate and prolate ellipsoids depends strongly on the orientation of the dipole moment of the transition with respect to the ellipsoid axes. In the case of spherical nanoparticles, a formula relating the decay rate A nano and the dielectric parameters of the nanocomposite and the volumetric content c of these particles in the nanocomposite is derived. This formula reduces to a known expression for spherical nanoparticles in the limit c ≪ 1, while the ratio A nano/ A bulk approaches unity as c tends to unity. The analysis shows that the approach used in a number of papers {H. P. Christensen, D. R. Gabbe, and H. P. Jenssen, Phys. Rev. B 25, 1467 (1982); R. S. Meltzer, S. P. Feofilov, B. Tissue, and H. B. Yuan, Phys. Rev. B 60, R14012 (1999); R. I. Zakharchenya, A. A. Kaplyanskii, A. B. Kulinkin, et al., Fiz. Tverd. Tela 45, 2104 (2003) [Phys. Solid State 45, 2209 (2003)]; G. Manoj Kumar, D. Narayana Rao, and G. S. Agarwal, Phys. Rev. Lett. 91, 203903 (2003); Chang-Kui Duan, Michael F. Reid, and Zhongqing Wang, Phys. Lett. A 343, 474 (2005); K. Dolgaleva, R. W. Boyd, and P. W. Milonni, J. Opt. Soc. Am. B 24, 516 (2007)}, for which the formula for A nano is derived merely by substituting the bulk refractive index by the effective refractive index of the nanocomposite must be revised, because the resulting ratio A nano/ A bulk turns out to depend on the local-field model. The formulas for the emission and absorption cross sections σnano for nanoparticles are derived. It is shown that the ratios σnano/σbulk and A nano/ A bulk are not equal in general, which can be used to improve the lasing parameters. The experimentally determined and theoretically evaluated decay times of metastable states of dopant rare-earth ions in crystalline YAG and Y2O3 nanoparticles are compared with the corresponding values for bulk crystals of the same structure.

Experimental transonic flutter characteristics of two 72 deg-sweep delta-wing models

NASA Technical Reports Server (NTRS)

Doggett, Robert V., Jr.; Soistmann, David L.; Spain, Charles V.; Parker, Ellen C.; Silva, Walter A.

1989-01-01

Transonic flutter boundaries are presented for two simple, 72 deg. sweep, low-aspect-ratio wing models. One model was an aspect-ratio 0.65 delta wing; the other model was an aspect-ratio 0.54 clipped-delta wing. Flutter boundaries for the delta wing are presented for the Mach number range of 0.56 to 1.22. Flutter boundaries for the clipped-delta wing are presented for the Mach number range of 0.72 to 0.95. Selected vibration characteristics of the models are also presented.

37 CFR 1.475 - Unity of invention before the International Searching Authority, the International Preliminary...

Code of Federal Regulations, 2010 CFR

2010-07-01

... general inventive concept (“requirement of unity of invention”). Where a group of inventions is claimed in... so linked as to form a single general inventive concept shall be made without regard to whether the...

Wakata exercises with Advanced Resistive Exercise Device (ARED) in Node 1 Unity

NASA Image and Video Library

2009-04-04

ISS018-E-044585 (4 April 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 18/19 flight engineer, exercises using the advanced Resistive Exercise Device (aRED) in the Unity node of the International Space Station.

Sturckow adds STS-128 crew patch to wall in Node 1 Unity

NASA Image and Video Library

2009-09-07

S128-E-007940 (7 Sept. 2009) --- NASA astronaut Rick Sturckow, STS-128 commander, adds his crew’s patch to the growing collection, in the Unity node, of insignias representing crews who have worked on the International Space Station.

Archambault places STS-119 patch in Node 1 Unity

NASA Image and Video Library

2009-03-25

S119-E-008112 (24 March 2009) --- Astronaut Lee Archambault, STS-119 commander, is pictured after adding his crew patch in the Unity node to the growing collection of those representing shuttle crews who have worked on the International Space Station.

Wakata exercises with Advanced Resistive Exercise Device (ARED) in Node 1 Unity

NASA Image and Video Library

2009-04-04

ISS018-E-044576 (4 April 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 18/19 flight engineer, exercises using the advanced Resistive Exercise Device (aRED) in the Unity node of the International Space Station.

Sturckow adds STS-128 crew patch to wall in Node 1 Unity

NASA Image and Video Library

2009-09-07

S128-E-007939 (7 Sept. 2009) --- NASA astronaut Rick Sturckow, STS-128 commander, adds his crew’s patch to the growing collection, in the Unity node, of insignias representing crews who have worked on the International Space Station.

Usachev with IRED hardware in Node 1/Unity module

NASA Image and Video Library

2001-04-07

ISS002-E-5508 (7 April 2001) --- Cosmonaut Yury V. Usachev, Expedition Two commander, wears a harness while conducting resistance exercises in the Unity Node 1 on the International Space Station (ISS). The image was recorded with a digital still camera.

Helms in Node 1/Unity module

NASA Image and Video Library

2001-04-07

ISS002-E-5511 (07 April 2001) --- Astronaut Susan J. Helms, Expedition Two flight engineer, pauses from moving through the Node 1 / Unity module of the International Space Station (ISS) to pose for a photograph. This image was recorded with a digital still camera.

Quantum coherence in the reflection of above barrier wavepackets

NASA Astrophysics Data System (ADS)

Petersen, Jakob; Pollak, Eli

2018-02-01

The quantum phenomenon of above barrier reflection is investigated from a time-dependent perspective using Gaussian wavepackets. The transition path time distribution, which in principle is experimentally measurable, is used to study the mean flight times ⟨t⟩R and ⟨t⟩T associated with the reflection and the transmission over the barrier paying special attention to their dependence on the width of the barrier. Both flight times, and their difference Δt, exhibit two distinct regimes depending on the ratio of the spatial width of the incident wavepacket and the length of the barrier. When the ratio is larger than unity, the reflection and transmission dynamics are coherent and dominated by the resonances above the barrier. The flight times ⟨t⟩R/T and the flight time difference Δt oscillate as a function of the barrier width (almost in phase with the transmission probability). These oscillations reflect a momentum filtering effect related to the coherent superposition of the reflected and transmitted waves. For a ratio less than unity, the barrier reflection and transmission dynamics are incoherent and the oscillations are absent. The barrier width which separates the coherent and incoherent regimes is identified analytically. The oscillatory structure of the time difference Δt as a function of the barrier width in the coherent regime is absent when considered in terms of the Wigner phase time delays for reflection and transmission. We conclude that the Wigner phase time does not correctly describe the temporal properties of above barrier reflection. We also find that the structure of the reflected and transmitted wavepackets depends on the coherence of the process. In the coherent regime, the wavepackets can have an overlapping peak structure, but the peaks are not fully resolved. In the incoherent regime, the wavepackets split in time into distinct separated Gaussian like waves, each one reflecting the number of times the wavepacket crosses the barrier region before exiting. A classical Wigner approximation, using classical trajectories which upon reaching an edge of the barrier are reflected or transmitted as if the edge was a step potential, is quantitative in the incoherent regime. The implications of the coherence observed on resonance reactive scattering are discussed.

Qualitative skeletal correlates of wing shape in extant birds (Aves: Neoaves).

PubMed

Hieronymus, Tobin L

2015-02-27

Among living fliers (birds, bats, and insects), birds display relatively high aspect ratios, a dimensionless shape variable that distinguishes long and narrow vs. short and broad wings. Increasing aspect ratio results in a functional tradeoff between low induced drag (efficient cruise) and increased wing inertia (difficult takeoff). Given the wide scope of its functional effects, the pattern of aspect ratio evolution is an important factor that contributes to the substantial ecological and phylogenetic diversity of living birds. However, because the feathers that define the wingtip (and hence wingspan and aspect ratio) often do not fossilize, resolution in the pattern of avian wing shape evolution is obscured by missing information. Here I use a comparative approach to investigate the relationship between skeletal proxies of flight feather attachment and wing shape. An accessory lobe of the internal index process of digit II-1, a bony correlate of distal primary attachment, shows weak but statistically significant relationships to aspect ratio and mass independent of other skeletal morphology. The dorsal phalangeal fossae of digit II-1, which house distal primaries VIII and IX, also show a trend of increased prominence with higher aspect ratio. Quill knobs on the ulna are examined concurrently, but do not show consistent signal with respect to wing shape. Although quill knobs are cited as skeletal correlates of flight performance in birds, their relationship to wing shape is inconsistent among extant taxa, and may reflect diverging selection pressures acting on a conserved architecture. In contrast, correlates of distal primary feather attachment on the major digit show convergent responses to increasing aspect ratio. In light of the diversity of musculoskeletal and integumentary mophology that underlies wing shape in different avian clades, it is unlikely that a single skeletal feature will show consistent predictive power across Neoaves. Confident inference of wing shape in basal ornithurine birds will require multiple lines of evidence, together with an understanding of clade-specific evolutionary trends within the crown.

Elliptic nozzle aspect ratio effect on controlled jet propagation

NASA Astrophysics Data System (ADS)

Aravindh Kumar, S. M.; Rathakrishnan, Ethirajan

2017-04-01

The present study deals with the control of a Mach 2 elliptic jet from a convergent-divergent elliptic nozzle of aspect ratio 4 using tabs at the nozzle exit. The experiments were carried out for rectangular and triangular tabs of the same blockage, placed along the major and minor axes of the nozzle exit, at different levels of nozzle expansion. The triangular tabs along the minor axis promoted superior mixing compared to the other controlled jets and caused substantial core length reduction at all the nozzle pressure ratios studied. The rectangular tabs along the minor axis caused core length reduction at all pressure ratios, but the values were minimal compared to that of triangular tabs along the minor axis. For all the test conditions, the mixing promotion caused by tabs along the major axis was inferior to that of tabs along the minor axis. The waves present in the core of controlled jets were visualized using a shadowgraph. Comparison of the present results with the results of a controlled Mach 2 elliptic jet of aspect ratio 2 (Aravindh Kumar and Sathakrishnan 2016 J. Propulsion Power 32 121-33, Aravindh Kumar and Rathakrishnan 2016 J. Aerospace Eng. at press (doi:10.1177/0954410016652921)) show that for all levels of expansion, the mixing effectiveness of triangular tabs along the minor axis of an aspect ratio 4 nozzle is better than rectangular or triangular tabs along the minor axis of an aspect ratio 2 nozzle.

Seismogenic width controls aspect ratios of earthquake ruptures

NASA Astrophysics Data System (ADS)

Weng, Huihui; Yang, Hongfeng

2017-03-01

We investigate the effect of seismogenic width on aspect ratios of earthquake ruptures by using numerical simulations of strike-slip faulting and an energy balance criterion near rupture tips. If the seismogenic width is smaller than a critical value, then ruptures cannot break the entire fault, regardless of the size of the nucleation zone. The seismic moments of these self-arresting ruptures increase with the nucleation size, forming nucleation-related events. The aspect ratios increase with the seismogenic width but are smaller than 8. In contrast, ruptures become breakaway and tend to have high aspect ratios (>8) if the seismogenic width is sufficiently large. But the critical nucleation size is larger than the theoretical estimate for an unbounded fault. The eventual seismic moments of breakaway ruptures do not depend on the nucleation size. Our results suggest that estimating final earthquake magnitude from the nucleation phase may only be plausible on faults with small seismogenic width.

Effect of Cell Aspect Ratio on Swarming Bacteria

NASA Astrophysics Data System (ADS)

Ilkanaiv, Bella; Kearns, Daniel B.; Ariel, Gil; Be'er, Avraham

2017-04-01

Swarming bacteria collectively migrate on surfaces using flagella, forming dynamic whirls and jets that consist of millions of individuals. Because some swarming bacteria elongate prior to actual motion, cell aspect ratio may play a significant role in the collective dynamics. Extensive research on self-propelled rodlike particles confirms that elongation promotes alignment, strongly affecting the dynamics. Here, we study experimentally the collective dynamics of variants of swarming Bacillus subtilis that differ in length. We show that the swarming statistics depends on the aspect ratio in a critical, fundamental fashion not predicted by theory. The fastest motion was obtained for the wild-type and variants that are similar in length. However, shorter and longer cells exhibit anomalous, non-Gaussian statistics and nonexponential decay of the autocorrelation function, indicating lower collective motility. These results suggest that the robust mechanisms to maintain aspect ratios may be important for efficient swarming motility. Wild-type cells are optimal in this sense.

Multielement suppressor nozzles for thrust augmentation systems.

NASA Technical Reports Server (NTRS)

Lawrence, R. L.; O'Keefe, J. V.; Tate, R. B.

1972-01-01

The noise reduction and nozzle performance characteristics of large-scale, high-aspect-ratio multielement nozzle arrays operated at low velocities were determined by test. The nozzles are selected for application to high-aspect-ratio augmentor suppressors to be used for augmentor wing airplanes. Significant improvements in noise characteristics for multielement nozzles over those of round or high-aspect-ratio slot nozzles are obtained. Elliptical noise patterns typical of slot nozzles are presented for high-aspect-ratio multielement nozzle arrays. Additional advantages are available in OASPL noise reduction from the element size and spacing. Augmentor-suppressor systems can be designed for maximum beam pattern directivity and frequency spectrum shaping advantages. Measurements of the nozzle wakes show a correlation with noise level data and frequency spectrum peaks. The noise and jet wake results are compared with existing prediction procedures based on empirical jet flow equations, Lighthill relationships, Strouhal number, and empirical shock-induced screech noise effects.

Stability of low aspect ratio inverted flags and rods in a uniform flow

NASA Astrophysics Data System (ADS)

Huertas-Cerdeira, Cecilia; Sader, John E.; Gharib, Morteza

2016-11-01

Cantilevered elastic plates and rods in an inverted configuration, where the leading edge is free to move and the trailing edge is clamped, undergo complex dynamics when subjected to a uniform flow. The stability of low aspect ratio inverted plates and rods is theoretically examined, showing that it is markedly different from that of their large aspect ratio counterpart. In the limit of zero aspect ratio, the undeflected equilibrium position is found to be stable for all wind speeds. A saddle-node bifurcation emerges at finite wind speed, giving rise to a strongly deflected stable and a weakly deflected unstable equilibria. This theory is compared to experimental measurements, where good agreement is found. This research was supported by a Grant of the Gordon and Betty Moore Foundation, the Australian Research Council Grants scheme and a "la Caixa" Fellowship Grant for Post-Graduate Studies of "la Caixa" Banking Foundation.

FFT-impedance spectroscopy analysis of the growth of magnetic metal nanowires in ultra-high aspect ratio InP membranes

NASA Astrophysics Data System (ADS)

Gerngross, M.-D.; Carstensen, J.; Föll, H.; Adelung, R.

2016-01-01

This paper reports on the characterization of the electrochemical growth process of magnetic nanowires in ultra-high-aspect ratio InP membranes via in situ fast Fourier transform impedance spectroscopy in a typical frequency range from 75 Hz to 18.5 kHz. The measured impedance data from the Ni, Co, and FeCo can be very well fitted using the same electric equivalent circuit consisting of a series resistance in serial connection to an RC-element and a Maxwell element. The impedance data clearly indicate the similarities in the growth behavior of Ni, Co and FeCo nanowires in ultra-high aspect ratio InP membranes—the beneficial impact of boric acid on the metal deposition in ultra-high aspect ratio membranes and the diffusion limitation of boric acid, as well as differences such as passivation or side reactions.

Rheology of concentrated suspensions of non-colloidal rigid fibers

NASA Astrophysics Data System (ADS)

Guazzelli, Elisabeth; Tapia, Franco; Shaikh, Saif; Butler, Jason E.; Pouliquen, Olivier

2017-11-01

Pressure and volume-imposed rheology is used to study suspensions of non-colloidal, rigid fibers in the concentrated regime for aspect ratios ranging from 3 to 15. The suspensions exhibit yield-stresses. Subtracting these apparent yield-stresses reveals a viscous scaling for both the shear and normal stresses. The variation in aspect ratio does not affect the friction coefficient (ratio of shear and normal stresses), but increasing the aspect ratio lowers the maximum volume fraction at which the suspension flows. Constitutive laws are proposed for the viscosities and the friction coefficient close to this maximum flowable fraction. The scaling of the stresses near this jamming transition are found to differ substantially from that of a suspension of spheres.

Technology, the Potomac Canal, and National Unity.

ERIC Educational Resources Information Center

Keller, Clair W.

1989-01-01

Illustrates the relationship between the technology of canal building and the development of national unity prior to the Revolutionary War. Examines George Washington's efforts to build the Potomac canal. Encourages students to consider the interrelationships among technology, resources, politics, and leadership. Includes two student handouts and…

Krikalev with CPAs in Node 1/Unity CBA

NASA Image and Video Library

2005-06-21

ISS011-E-09392 (21 June 2005) --- Cosmonaut Sergei K. Krikalev, Expedition 11 commander representing Russia's Federal Space Agency, moves one of the two Control Panel Assemblies (CPA) from the Unity node’s Common Berthing Assembly (CBA) on the International Space Station (ISS).

Lu and Kaleri in Node 1/Unity module

NASA Image and Video Library

2003-10-26

ISS007-E-18035 (26 October 2003) --- Cosmonaut Alexander Y. Kaleri (left), Expedition 8 flight engineer, and astronaut Edward T. Lu, Expedition 7 NASA ISS science officer and flight engineer, hold tools in the Unity node on the International Space Station (ISS). Kaleri represents Rosaviakosmos.

Expedition Seven Science Officer Lu works with IRED hardware in Node 1/Unity

NASA Image and Video Library

2003-06-23

ISS007-E-08023 (23 June 2003) --- Astronaut Edward T. Lu, Expedition 7 NASA ISS science officer and flight engineer, performs maintenance on the Interim Resistive Exercise Device (IRED) Assembly in the Unity node on the International Space Station (ISS).

Krikalev with mission patch in Node 1 / Unity module

NASA Image and Video Library

2005-06-21

ISS011-E-09363 (21 June 2005) --- Cosmonaut Sergei K. Krikalev, Expedition 11 commander representing Russia's Federal Space Agency, adds the Expedition 11 patch to the Unity node’s growing collection of insignias representing crews who have worked on the international space station.

Usachev with IRED hardware in Node 1/Unity module

NASA Image and Video Library

2001-04-07

ISS002-E-5507 (07 April 2001) --- Cosmonaut Yury V. Usachev, Expedition Two mission commander, wears a harness while conducting resistance exercises in the Node 1 / Unity module of the International Space Station (ISS). This image was recorded with a digital still camera.

Phillips exercises with RED in Node 1/Unity module

NASA Image and Video Library

2005-05-18

ISS011-E-06404 (18 May 2005) --- Astronaut John L. Phillips, Expedition 11 NASA space station science officer and flight engineer, wearing squat harness pads, exercises using the Interim Resistive Exercise Device (IRED) equipment in the Unity node of the International Space Station.

Numerical Simulations of Noise Generated by High Aspect Ratio Supersonic Rectangular Jets - Validation

NASA Astrophysics Data System (ADS)

Viswanath, Kamal; Johnson, Ryan; Kailasanath, Kailas; Malla, Bhupatindra; Gutmark, Ephraim

2017-11-01

The noise from high performance jet engines of both civilian and military aircraft is an area of active concern. Asymmetric exhaust nozzle configurations, in particular rectangular, potentially offer a passive way of modulating the farfield noise and are likely to become more important in the future. High aspect ratio nozzles offer the further benefit of easier airframe integration. In this study we validate the far field noise for ideally and over expanded supersonic jets issuing from a high aspect ratio rectangular nozzle geometry. Validation of the acoustic data is performed against experimentally recorded sound pressure level (SPL) spectra for a host of observer locations around the asymmetric nozzle. Data is presented for a slightly heated jet case for both nozzle pressure ratios. The contrast in the noise profile from low aspect ratio rectangular and circular nozzle jets are highlighted, especially the variation in the azimuthal direction that shows ``quiet'' and ``loud'' planes in the farfield in the peak noise direction. This variation is analyzed in the context of the effect of mixing at the sharp corners, the sense of the vortex pairs setup in the exit plane, and the evolution of the high aspect ratio exit cross-section as it propagates downstream including possible axis-switching. Supported by Office of Naval Research (ONR) through the Computational Physics Task Area under the NRL 6.1 Base Program.