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Sample records for concave costs oberwolfach

  1. DETERMINISTIC PRODUCTION PLANNING WITH CONCAVE COSTS AND CAPACITY CONSTRAINTS.

    DTIC Science & Technology

    INDUSTRIAL PRODUCTION , MANAGEMENT PLANNING AND CONTROL), (*PRODUCTION CONTROL, DYNAMIC PROGRAMMING), INVENTORY ANALYSIS, SCHEDULING, COST EFFECTIVENESS, STORAGE, MANPOWER, OPTIMIZATION, MATHEMATICAL MODELS, ALGORITHMS

  2. Optimal transportation network with concave cost functions: loop analysis and algorithms.

    PubMed

    Shao, Zhen; Zhou, Haijun

    2007-06-01

    Transportation networks play a vital role in modern societies. Structural optimization of a transportation system under a given set of constraints is an issue of great practical importance. For a general transportation system whose total cost C is determined by C = Sigma(icost of the flow I(ij) between node i and node j, Banavar and co-workers [Phys. Rev. Lett. 84, 4745 (2000)] proved that the optimal network topology is a tree if C(ij) proportional |I(ij)|(gamma) with 0 < gamma < 1. The same conclusion also holds in the more general case where all the flow costs are strictly concave functions of the flow I(ij). To further understand the qualitative difference between systems with concave and convex cost functions, a loop analysis of transportation cost is performed in the present paper, and an alternative mathematical proof of the optimality of tree-formed networks is given. The simple intuitive picture of this proof then leads to an efficient global algorithm for the searching of optimal structures for a given transportation system with concave cost functions.

  3. Log-Concavity and Strong Log-Concavity: a review

    PubMed Central

    Saumard, Adrien; Wellner, Jon A.

    2016-01-01

    We review and formulate results concerning log-concavity and strong-log-concavity in both discrete and continuous settings. We show how preservation of log-concavity and strongly log-concavity on ℝ under convolution follows from a fundamental monotonicity result of Efron (1969). We provide a new proof of Efron's theorem using the recent asymmetric Brascamp-Lieb inequality due to Otto and Menz (2013). Along the way we review connections between log-concavity and other areas of mathematics and statistics, including concentration of measure, log-Sobolev inequalities, convex geometry, MCMC algorithms, Laplace approximations, and machine learning. PMID:27134693

  4. Log-Concavity and Strong Log-Concavity: a review.

    PubMed

    Saumard, Adrien; Wellner, Jon A

    We review and formulate results concerning log-concavity and strong-log-concavity in both discrete and continuous settings. We show how preservation of log-concavity and strongly log-concavity on ℝ under convolution follows from a fundamental monotonicity result of Efron (1969). We provide a new proof of Efron's theorem using the recent asymmetric Brascamp-Lieb inequality due to Otto and Menz (2013). Along the way we review connections between log-concavity and other areas of mathematics and statistics, including concentration of measure, log-Sobolev inequalities, convex geometry, MCMC algorithms, Laplace approximations, and machine learning.

  5. Rotating concave eddy current probe

    DOEpatents

    Roach, Dennis P.; Walkington, Phil; Rackow, Kirk A.; Hohman, Ed

    2008-04-01

    A rotating concave eddy current probe for detecting fatigue cracks hidden from view underneath the head of a raised head fastener, such as a buttonhead-type rivet, used to join together structural skins, such as aluminum aircraft skins. The probe has a recessed concave dimple in its bottom surface that closely conforms to the shape of the raised head. The concave dimple holds the probe in good alignment on top of the rivet while the probe is rotated around the rivet's centerline. One or more magnetic coils are rigidly embedded within the probe's cylindrical body, which is made of a non-conducting material. This design overcomes the inspection impediment associated with widely varying conductivity in fastened joints.

  6. Detection of Convexity and Concavity in Context

    ERIC Educational Resources Information Center

    Bertamini, Marco

    2008-01-01

    Sensitivity to shape changes was measured, in particular detection of convexity and concavity changes. The available data are contradictory. The author used a change detection task and simple polygons to systematically manipulate convexity/concavity. Performance was high for detecting a change of sign (a new concave vertex along a convex contour…

  7. Detection of Convexity and Concavity in Context

    ERIC Educational Resources Information Center

    Bertamini, Marco

    2008-01-01

    Sensitivity to shape changes was measured, in particular detection of convexity and concavity changes. The available data are contradictory. The author used a change detection task and simple polygons to systematically manipulate convexity/concavity. Performance was high for detecting a change of sign (a new concave vertex along a convex contour…

  8. Mesh segmentation with concavity-aware fields.

    PubMed

    Au, Oscar Kin-Chung; Zheng, Youyi; Chen, Menglin; Xu, Pengfei; Tai, Chiew-Lan

    2012-07-01

    This paper presents a simple and efficient automatic mesh segmentation algorithm that solely exploits the shape concavity information. The method locates concave creases and seams using a set of concavity-sensitive scalar fields. These fields are computed by solving a Laplacian system with a novel concavity-sensitive weighting scheme. Isolines sampled from the concavity-aware fields naturally gather at concave seams, serving as good cutting boundary candidates. In addition, the fields provide sufficient information allowing efficient evaluation of the candidate cuts. We perform a summarization of all field gradient magnitudes to define a score for each isoline and employ a score-based greedy algorithm to select the best cuts. Extensive experiments and quantitative analysis have shown that the quality of our segmentations are better than or comparable with existing state-of-the-art more complex approaches.

  9. Flow behind concave shock waves

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2017-09-01

    Curved shock theory is introduced and applied to calculate the flow behind concave shock waves. For sonic conditions, three characterizing types of flow are identified, based on the orientation of the sonic line, and it is shown that, depending on the ratio of shock curvatures, a continuously curving shock can exist with Type III flow, where the sonic line intercepts the reflected characteristics from the shock, thus preventing the formation of a reflected shock. The necessary shock curvature ratio for a Type III sonic point does not exist for a hyperbolic shock so that it will revert to Mach reflection for all Mach numbers. A demonstration is provided, by CFD calculations, at Mach 1.2 and 3.

  10. Flow behind concave shock waves

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2017-03-01

    Curved shock theory is introduced and applied to calculate the flow behind concave shock waves. For sonic conditions, three characterizing types of flow are identified, based on the orientation of the sonic line, and it is shown that, depending on the ratio of shock curvatures, a continuously curving shock can exist with Type III flow, where the sonic line intercepts the reflected characteristics from the shock, thus preventing the formation of a reflected shock. The necessary shock curvature ratio for a Type III sonic point does not exist for a hyperbolic shock so that it will revert to Mach reflection for all Mach numbers. A demonstration is provided, by CFD calculations, at Mach 1.2 and 3.

  11. Concave binding of cationic Li to quadrannulene.

    PubMed

    Dang, Jing-Shuang; Wang, Wei-Wei; Zhao, Xiang; Nagase, Shigeru

    2017-08-09

    Binding of Li(+) to quadrannulene and its influence on buckybowl functionalization are introduced. The concave-trapped Li(+) acts as a Lewis acid and the rate of Diels-Alder cycloaddition is enhanced 10(8) times. A sandwiched bowl-Li(+)-bowl structure is stabilized via concave-cation-convex interactions, indicating the promoted role of Li(+) in buckybowl assembly.

  12. Perceiving parts and shapes from concave surfaces

    PubMed Central

    Cate, Anthony D.; Behrmann, Marlene

    2009-01-01

    “A hole is nothing at all, but it can break your neck.” In a similar fashion to the danger illustrated by this folk paradox, concave regions pose difficulties to theories of visual shape perception. We can readily identify their shapes, but according to principles of how observers determine part boundaries, concavities in planar surface should have very different figural shapes from the ones we perceive. Three experiments tested the hypothesis that observers perceive local image features differently from simulated 3D concave and convex regions, but use them to arrive at similar shape percepts. Stimuli were shape-from-shading images containing regions that appeared either concave or convex in depth depending on their orientation in the picture plane. The results show that concavities did not benefit from the same global object-based attention or holistic shape encoding as convexities, and that participants relied on separable spatial dimensions to judge figural shape in concavities. Concavities may exploit a secondary process for shape perception that allows regions composed of perceptually independent features ultimately to be perceived as gestalts. PMID:20045886

  13. Strain responsive concave and convex microlens arrays

    NASA Astrophysics Data System (ADS)

    Chandra, Dinesh; Yang, Shu; Lin, Pei-Chun

    2007-12-01

    We report the fabrication of single-component, strain responsive microlens arrays with real-time tunability. The concave lens array is fabricated by patterning hard oxide layer on a bidirectionally prestretched soft elastomer, poly(dimethylsiloxane) (PDMS) followed by confined buckling upon release of the prestrain. The convex microlens array is replica molded from the concave lenses in PDMS. Due to difference in lens formation mechanisms, the two types of lenses show different tunable range of focal length in response to the applied strain: large focal length change is observed from the concave microlens array, whereas that from the convex microlens array is much smaller.

  14. Concave nanomagnets with widely tunable anisotropy

    DOEpatents

    Lambson, Brian; Gu, Zheng; Carlton, David; Bokor, Jeffrey

    2014-07-01

    A nanomagnet having widely tunable anisotropy is disclosed. The disclosed nanomagnet is a magnetic particle with a convex shape having a first magnetically easy axis. The convex shape is modified to include at least one concavity to urge a second magnetically easy axis to form substantially offset from the first magnetically easy axis. In at least one embodiment, the convex shape is also modified to include at least one concavity to urge a second magnetically easy axis to form with a magnetic strength substantially different from the first magnetically easy axis.

  15. Infants' Perception of Information along Object Boundaries: Concavities versus Convexities

    ERIC Educational Resources Information Center

    Bhatt, Ramesh S.; Hayden, Angela; Reed, Andrea; Bertin, Evelin; Joseph, Jane

    2006-01-01

    Object parts are signaled by concave discontinuities in shape contours. In seven experiments, we examined whether 5- and 6 1/2-month-olds are sensitive to concavities as special aspects of contours. Infants of both ages detected discrepant concave elements amid convex distractors but failed to discriminate convex elements among concave…

  16. Infants' Perception of Information along Object Boundaries: Concavities versus Convexities

    ERIC Educational Resources Information Center

    Bhatt, Ramesh S.; Hayden, Angela; Reed, Andrea; Bertin, Evelin; Joseph, Jane

    2006-01-01

    Object parts are signaled by concave discontinuities in shape contours. In seven experiments, we examined whether 5- and 6 1/2-month-olds are sensitive to concavities as special aspects of contours. Infants of both ages detected discrepant concave elements amid convex distractors but failed to discriminate convex elements among concave…

  17. Longitudinal vortices in concave surface boundary layer

    NASA Astrophysics Data System (ADS)

    Crane, R. I.,; Winoto, S. H.

    1980-01-01

    Local measurements of mean and fluctuating velocity by laser anemometer were made inside the developing concave surface boundary layer in a free surface water channel at Reynolds numbers up to 16000. Concave surface radius was 3.5 times channel width and the ratio of spanwise mean boundary layer thickness to surface radius ranged between 0.03 and 0.11. Systems of longtitudinal vortices developed without artificial triggering. Vortex wavelength varied across the span by as much as a factor of 2, but mean wavelength was typically 1.3 times the boundary layer thickness and did not vary significantly in the flow direction. Continuous vortex growth at Reynolds number = 9800 contrasted with apparent breakup of the vortices at Reynolds number = 16000.

  18. Concave points for separating touching particles

    NASA Astrophysics Data System (ADS)

    Chaves, Deisy; Trujillo, Maria; Barraza, Juan Manuel

    2015-03-01

    Separation of touching objects/particles is a step before measuring morphological characteristics. An approach for identifying and splitting touching char particles is presented. The proposed approach is based on two processes. First, concave points are detected using a concavity measure and a list of touching point candidates is built. Second, separation lines are identified using location, length, blur and size. A decision criterion is derived for deciding whether or not to split a particle. The proposed approach is evaluated using 180 images of char particles and compared to the Watershed algorithm. The evaluation was twofold: quantifying the accuracy of identifying touching particles and measuring the separation quality. Expert criteria are used as a ground truth for qualitative evaluations. A good agreement between the visual judgement and automatic results was obtained, using the proposed approach.

  19. Calculated Communications In A Concave World

    DTIC Science & Technology

    2016-02-16

    Calculated Communications can also be visualized like: 23 In this model , as classification increases, so does risk when proactively divulging details...there is less risk, so proactive messaging is possible and, in Calculated Communications , should be encouraged. What this model attempts to also...AIR WAR COLLEGE AIR UNIVERSITY CALCULATED COMMUNICATIONS IN A CONCAVE WORLD by Lance A. Wilkins, Colonel, United States Air Force A

  20. Broadband converging plano-concave lens.

    PubMed

    Yang, Rui; Lei, Zhenya; Chen, Lei; Zhang, Jiawei; Wang, Zhaoxu; Xie, Yongjun

    2013-07-01

    A plano-concave lens with source-tailored geometric profile and transformational gradient index is proposed for broadband illumination. Such a design, capable of focusing and collimating the electromagnetic fields, fulfils the functionality of a converging lens and can also achieve a steerable beam and multiple beams efficiently. Nonresonant synthesis with a perforated dielectric plate and dielectric rod arrays is demonstrated for the lensing realization, promising a wide operating frequency band in the practical implementation.

  1. Sensitive visual test for concave diffraction gratings.

    NASA Technical Reports Server (NTRS)

    Bruner, E. C., Jr.

    1972-01-01

    A simple visual test for the evaluation of concave diffraction gratings is described. It is twice as sensitive as the Foucault knife edge test, from which it is derived, and has the advantage that the images are straight and free of astigmatism. It is particularly useful for grating with high ruling frequency where the above image faults limit the utility of the Foucault test. The test can be interpreted quantitatively and can detect zonal grating space errors of as little as 0.1 A.

  2. Machine for fabricating axially symmetric concave aspherics.

    PubMed

    Hashimoto, H

    1973-07-01

    A machine has been constructed for fabricating concave aspheric surfaces of diameter up to 200 mm and reference radius from 20 mm to 150 mm. The principle is to use a plastic-bonded silicon carbide wheel with a convex cutting surface, which is continually dressed by a diamond form dresser. The cam used for directing the grinding wheel is cut on a numerically controlled jig borer with a tool of the same diameter as the cam follower. In operation, the location of the diamond dresser is used to provide feedback corrections for the grinding wheel.

  3. Imaging Spectrometers Using Concave Holographic Gratings

    NASA Technical Reports Server (NTRS)

    Gradie, J.; Wang, S.

    1993-01-01

    Imaging spectroscopy combines the spatial attributes of imaging with the compositionally diagnostic attributes of spectroscopy. For spacebased remote sensing applications, mass, size, power, data rate, and application constrain the scanning approach. For the first three approaches, substantial savings in mass and size of the spectrometer can be achieved in some cases with a concave holographic grating and careful placement of an order-sorting filter. A hologram etched on the single concave surface contains the equivalent of the collimating, dispersing, and camera optics of a conventional grating spectrometer and provides substantial wavelength dependent corrections for spherical aberrations and a flat focal field. These gratings can be blazed to improve efficiency when used over a small wavelength range or left unblazed for broadband uniform efficiency when used over a wavelength range of up to 2 orders. More than 1 order can be imaged along the dispersion axis by placing an appropriately designed step order-sorting filter in front of the one- or two-dimensional detector. This filter can be shaped for additional aberration corrections. The VIRIS imaging spectrometer based on the broadband design provides simultaneous imaging of the entrance slit from lambda = 0.9 to 2.6 microns (1.5 orders) onto a 128 x 128 HgCdTe detector (at 77 K). The VIRIS spectrometer was used for lunar mapping with the UH 24.in telescope at Mauna Kea Observatory. The design is adaptable for small, low mass, space based imaging spectrometers.

  4. Verification of conicoidal concave surfaces by keratometry

    PubMed Central

    Douthwaite, William A.; Mallen, Edward A.H.

    2010-01-01

    Purpose To investigate the possibility of using a keratometer to check the specification of the conicoidal back surface of rigid contact lenses. Methods A conicoidal surface can be described by quoting two parameters. The most useful for the contact lens practitioner are the apical radius (curvature) and the P-value (asphericity). A keratometer was used to measure calibrated aspheric concave surfaces with the surfaces tilted in relation to the keratometer optical axis in order to acquire sagittal radii of curvature for various regions across the concave surface. The known surface characteristics were used to apply a correction factor to the results in order to allow derivation of the surface apical radius and P-value by keratometry. Results The 95% confidence limits suggest an estimate to within —0.014 to +0.011 mm for apical radius and —0.011 to +0.009 for the P-value compared to the results derived by form Talysurf analysis. The coefficient of repeatability was 0.029 mm for apical radius and 0.031 for the P-value. Conclusions The investigation supports the notion that the keratometer could be used to check both the curvature and the asphericity of conicoidal back surface rigid contact lenses.

  5. Cesáro partial sums of concave univalent functions

    NASA Astrophysics Data System (ADS)

    Aldawish, Ibtisam; Darus, Maslina

    2014-06-01

    In this article, we consider the Cesáro partial sums of certain concave univalent functions. We studied geometric properties of the Cesáro partial sums of certain concave univalent functions in the open unit disk. Examples are illustrated.

  6. GNCCP-Graduated NonConvexityand Concavity Procedure.

    PubMed

    Zhi-Yong Liu; Hong Qiao

    2014-06-01

    In this paper we propose the graduated nonconvexity and concavity procedure (GNCCP) as a general optimization framework to approximately solve the combinatorial optimization problems defined on the set of partial permutation matrices. GNCCP comprises two sub-procedures, graduated nonconvexity which realizes a convex relaxation and graduated concavity which realizes a concave relaxation. It is proved that GNCCP realizes exactly a type of convex-concave relaxation procedure (CCRP), but with a much simpler formulation without needing convex or concave relaxation in an explicit way. Actually, GNCCP involves only the gradient of the objective function and is therefore very easy to use in practical applications. Two typical related NP-hard problems, partial graph matching and quadratic assignment problem (QAP), are employed to demonstrate its simplicity and state-of-the-art performance.

  7. Quantum entropies, Schur concavity and dynamical semigroups

    NASA Astrophysics Data System (ADS)

    Aniello, Paolo

    2017-01-01

    Entropy plays a fundamental role in several branches of physics. In the quantum setting, one usually considers the von Neumann entropy, but other useful quantities have been proposed in the literature; e.g., the Rényi and the Tsallis entropies. The evolution of an open quantum system, described by a semigroup of dynamical maps (in short, a dynamical semigroup), may decrease a quantum entropy, for some initial condition. We will discuss various characterizations of those dynamical semigroups that, for every initial condition, do not decrease a general class of quantum entropies, which is defined using the notion of Schur concavity of a function. We will not assume that such a dynamical semigroup be completely positive, the physical justification of this condition being controversial. Therefore, we will consider semigroups of trace-preserving, positive — but not necessarily completely positive — linear maps. We will next focus on a special class of (completely positive) dynamical semigroups, the twirling semigroups, having applications in quantum information science. We will argue that the whole class of dynamical semigroups that do not decrease a quantum entropy can be obtained as a suitable generalization of the twirling semigroups.

  8. Elliptical concave microlens arrays built in the photosensitive TiO2/ormosils hybrid films

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehua; Que, Wenxiu; Javed, Hafiz M. Asif; Wei, Wei

    2014-11-01

    Photosensitive TiO2/organically modified silane hybrid thin films were prepared by a low-temperature sol-gel spin-coating technique. Optical and structural properties of the hybrid films with different titanium contents were characterized by prism coupling technique, UV-visible spectroscopy, Fourier transform infrared spectroscopy, and thermal gravimetric analysis. Advantages for fabrication of elliptical concave micro-lens arrays (MLAs) based on the as-prepared hybrid films were demonstrated by combining polydimethylsiloxane soft mold with a UV-cured imprint technique. Results indicate that the as-prepared hybrid films have great applicability for the fabrication of photonic components, and the fabrication technique provides a simple and cost-effective way for the fabrication of the sol-gel elliptical concave MLAs.

  9. Classroom Note: Concavity and the Second Law of Thermodynamics

    ERIC Educational Resources Information Center

    Dunning-Davies, J.

    2003-01-01

    The importance of the mathematical notion of concavity in relation to thermodynamics is stressed and it is shown how it can be useful in increasing the enthusiasm of physics' students for their mathematics' courses.

  10. Hydrodynamics and sedimentology of concave benches in a lowland river

    NASA Astrophysics Data System (ADS)

    Vietz, Geoff J.; Rutherfurd, Ian D.; Stewardson, Michael J.; Finlayson, Brian L.

    2012-04-01

    This paper describes the hydrodynamics and sedimentation associated with concave-bank benches (concave benches) which are the fine-grained sediment deposits considered geomorphically and ecologically important in meandering rivers. Most notions previously associated with concave bench formation ignore hydrodynamic complexities and consequently fail to recognise the importance of bankfull flows: being commonly based on inference from stratigraphic profiling or casual observation of hydrodynamics. Concave benches are a depositional anomaly since their location in the channel is commonly associated with scour. Mature concave benches are formed by separation of the reverse flow (upriver flow) from the stem flow (downriver flow) in an abrupt bend whereby deposition is dominated by vertical accretion of suspended sediments. For this study two-dimensional hydrodynamic modelling in conjunction with the collection and analysis of contemporary sediments is used to demonstrate the persistence of reverse flow over concave benches for stages from incipient bench inundation to bankfull and greater. For two mature concave benches on the Ovens River, southeast Australia, bankfull flows were depositional with shear stresses commonly < 0.5 N m- 2 incapable of scouring the bench surface. Localised scour is restricted to the streamward edge of the bench during the early and late phases of an inundation event. Discharges most conducive to deposition were found to be higher than anticipated, in the range of 40 to 80% of bankfull (benches initially inundated at 20% of bankfull), and could be responsible for bench formation. These findings highlight the potential negative impact of river regulation on channel morphology by reducing the frequency of flows forming in-channel benches and increasing the occurrence of destructive flows.

  11. Convexity and concavity constants in Lorentz and Marcinkiewicz spaces

    NASA Astrophysics Data System (ADS)

    Kaminska, Anna; Parrish, Anca M.

    2008-07-01

    We provide here the formulas for the q-convexity and q-concavity constants for function and sequence Lorentz spaces associated to either decreasing or increasing weights. It yields also the formula for the q-convexity constants in function and sequence Marcinkiewicz spaces. In this paper we extent and enhance the results from [G.J.O. Jameson, The q-concavity constants of Lorentz sequence spaces and related inequalities, Math. Z. 227 (1998) 129-142] and [A. Kaminska, A.M. Parrish, The q-concavity and q-convexity constants in Lorentz spaces, in: Banach Spaces and Their Applications in Analysis, Conference in Honor of Nigel Kalton, May 2006, Walter de Gruyter, Berlin, 2007, pp. 357-373].

  12. Development of Concave Conical Gear Used for Marine Transmissions

    NASA Astrophysics Data System (ADS)

    Komatsubara, Hidenori; Mitome, Ken-Ichi; Ohmachi, Tatsuya

    In the first report, the method of generating Concave conical gears was presented. In this paper, first the principal normal radii of the tooth surface generated by this method are expressed theoretically in terms of the basic dimensions of the gear and the tool. The principal normal radii of test gears are measured and found to be in good agreement with the theoretical values. Secondly, the allowable normal load of a pair of Concave conical gears is obtained. Tooth bearing tests prove that the Hertzian contact ellipse is larger than that of the conventional conical gear. Thus it is proven that the method of designing a pair of Concave conical gears is of practical use.

  13. Development of Concave Conical Gear Used for Marine Transmissions

    NASA Astrophysics Data System (ADS)

    Komatsubara, Hidenori; Mitome, Ken-Ichi; Ohmachi, Tatsuya

    Conical involute gears used for marine transmissions are mostly helical ones. These gears are available in the form of not only intersecting axis gears but also nonintersecting-nonparallel axis gears. The contact between tooth surfaces of a pair of gears is the point contact. Tooth surface durability is generally low. In order to overcome this weak point, one of the authors invented a new type of conical gear called “Concave conical gear”. Concave conical gear has higher tooth durability than the conventional conical involute gear. In this paper, a method to generate the helical Concave conical gear is newly developed. First, the principle of the generating method is introduced, and the tooth surface is analyzed theoretically. Second, test gears are ground. Tooth surfaces of the test gears are measured and compared with theoretical ones, and good agreement is observed.

  14. The effects of concave curvature on turbulent boundary layer structure

    NASA Astrophysics Data System (ADS)

    Jeans, A. H.; Johnston, J. P.

    This paper reports the results of flow visualization studies on the structure of turbulent boundary layers over concave walls. A flat plate turbulent boundary layer was grown on one wall of a straight, large water channel and then passed over a concave wall. The flow was visualized in two ways, (1) by injecting dyes into the sublayers and (2) by generating hydrogen bubbles on fine wires placed in the flow. Mean velocity and turbulence intensity profiles were measured using a hot film anemometer. The boundary layer on the concave wall was found to be dominated by randomly occurring, large-scale sweeps and ejections. The stationary roll-cells, or Taylor-Goertler structures are not a feature of this flow. The sweeps appear to inhibit the usual bursting mechanism for producing turbulence near the wall, while the ejections appear to create additional turbulence in the outer flow.

  15. Artifact reduction through the use of concave linear arrays

    NASA Astrophysics Data System (ADS)

    Slayton, Michael H.; Roelike, Tim P.

    1992-11-01

    Ultrasonic imaging arrays are severely restricted in design and imaging quality by artifacts associated with the geometry of the arrays. Linear and convex linear arrays are limited by the appearance of side lobes and grating lobes in the images, which obscure diagnostically useful information. Limited access to parts of the body useful for accurate diagnosis (e.g., intercostal imaging) in many cases forces the use of phased arrays or mechanical arrays in place of linear and curved linear arrays. One of the ways to avoid the limitations and utilize the advantage of the curved linear configuration is to use a concave design. This paper compares the results of simulations of the concave and convex designs, and the degree of reduction of grating lobes. The simulation results are verified with beam plots of each design. Concave arrays are fabricated and clinical results are shown for intercostal and subcostal abdomen imaging.

  16. Fabrication of concave and convex potassium bromide lens arrays by compression molding.

    PubMed

    de la Barrière, Florence; Druart, Guillaume; Guèrineau, Nicolas; Taboury, Jean; Gueugnot, Alain; Huc, Vincent

    2012-07-20

    A new simple and cost-effective method has been developed for the fabrication of both plano-convex and plano-concave lens arrays with potentially important sag heights. The process is based on the use of potassium bromide (KBr) powder. At ambient temperature and under pressure, KBr powder is compressed on a molding die with the desired shape to form a solid lens array. The quality of the lens arrays has been assessed, and we present the first image produced by a converging KBr lens array.

  17. Monotonicity, concavity, and convexity of fractional derivative of functions.

    PubMed

    Zhou, Xian-Feng; Liu, Song; Zhang, Zhixin; Jiang, Wei

    2013-01-01

    The monotonicity of the solutions of a class of nonlinear fractional differential equations is studied first, and the existing results were extended. Then we discuss monotonicity, concavity, and convexity of fractional derivative of some functions and derive corresponding criteria. Several examples are provided to illustrate the applications of our results.

  18. Concavity of Solutions of the Porous Medium Equation.

    DTIC Science & Technology

    1985-08-01

    R x (0,T), for initial data not necessarily concave. She obtains results about existence, uniqueness and nonuniqueness for suitable classes of weak... Lipschitz -continuous curves (the interfaces), si(o) = a, s2(0) = b, and (-1) isi(t) is nondecreasing in time. Along the interfaces the derivative vx is

  19. Calculation of the diffraction efficiency on concave gratings based on Fresnel-Kirchhoff's diffraction formula.

    PubMed

    Huang, Yuanshen; Li, Ting; Xu, Banglian; Hong, Ruijin; Tao, Chunxian; Ling, Jinzhong; Li, Baicheng; Zhang, Dawei; Ni, Zhengji; Zhuang, Songlin

    2013-02-10

    Fraunhofer diffraction formula cannot be applied to calculate the diffraction wave energy distribution of concave gratings like plane gratings because their grooves are distributed on a concave spherical surface. In this paper, a method based on the Kirchhoff diffraction theory is proposed to calculate the diffraction efficiency on concave gratings by considering the curvature of the whole concave spherical surface. According to this approach, each groove surface is divided into several limited small planes, on which the Kirchhoff diffraction field distribution is calculated, and then the diffraction field of whole concave grating can be obtained by superimposition. Formulas to calculate the diffraction efficiency of Rowland-type and flat-field concave gratings are deduced from practical applications. Experimental results showed strong agreement with theoretical computations. With the proposed method, light energy can be optimized to the expected diffraction wave range while implementing aberration-corrected design of concave gratings, particularly for the concave blazed gratings.

  20. Critical Concavity of a Drainage Basin for Steady-State

    NASA Astrophysics Data System (ADS)

    Byun, Jongmin; Paik, Kyungrock

    2015-04-01

    Longitudinal profiles of natural streams are known to show concave forms. Saying A as drainage area, channel gradient S can be expressed as the power-law, S≈A-θ (Flint, 1974), which is one of the scale-invariant features of drainage basin. According to literature, θ of most natural streams falls into a narrow range (0.4 < θ < 0.7) (Tucker and Whipple, 2002). It leads to fundamental questions: 'Why does θ falls into such narrow range?' and 'How is this related with other power-law scaling relationships reported in natural drainage basins?' To answer above questions, we analytically derive θ for a steady-state drainage basin following Lane's equilibrium (Lane, 1955) throughout the corridor and named this specific case as the 'critical concavity'. In the derivation, sediment transport capacity is estimated by unit stream power model (Yang, 1976), yielding a power function of upstream area. Stability of channel at a local point occurs when incoming flux equals outgoing flux at the point. Therefore, given the drainage at steady-state where all channel beds are stable, the exponent of the power function should be zero. From this, we can determine the critical concavity. Considering ranges of variables associated in this derivation, critical concavity cannot be resolved as a single definite value, rather a range of critical concavity is suggested. This range well agrees with the widely reported range of θ (0.4 < θ < 0.7) in natural streams. In this theoretical study, inter-relationships between power-laws such as hydraulic geometry (Leopold and Maddock, 1953), dominant discharge-drainage area (Knighton et al., 1999), and concavity, are coupled into the power-law framework of stream power sediment transport model. This allows us to explore close relationships between their power-law exponents: their relative roles and sensitivity. Detailed analysis and implications will be presented. References Flint, J. J., 1974, Stream gradient as a function of order, magnitude

  1. Curvature morphology of the mandibular dentition and the development of concave-convex vertical stripping instruments.

    PubMed

    Ihlow, Dankmar; Kubein-Meesenburg, Dietmar; Hunze, Justus; Dathe, Henning; Planert, Jens; Schwestka-Polly, Rainer; Nägerl, Hans

    2002-07-01

    Radii for concave-convex vertical stripping instruments can be derived from measurements of the natural curvature morphology in the horizontal contact area of the mandibular dentition. The concave-convex adjustment of contacts in the anterior dental arch with a newly developed set of concave-convex stripping instruments should enable orthodontic crowding problems to be alleviated biomechanically.

  2. GLOBAL SOLUTIONS TO FOLDED CONCAVE PENALIZED NONCONVEX LEARNING

    PubMed Central

    Liu, Hongcheng; Yao, Tao; Li, Runze

    2015-01-01

    This paper is concerned with solving nonconvex learning problems with folded concave penalty. Despite that their global solutions entail desirable statistical properties, there lack optimization techniques that guarantee global optimality in a general setting. In this paper, we show that a class of nonconvex learning problems are equivalent to general quadratic programs. This equivalence facilitates us in developing mixed integer linear programming reformulations, which admit finite algorithms that find a provably global optimal solution. We refer to this reformulation-based technique as the mixed integer programming-based global optimization (MIPGO). To our knowledge, this is the first global optimization scheme with a theoretical guarantee for folded concave penalized nonconvex learning with the SCAD penalty (Fan and Li, 2001) and the MCP penalty (Zhang, 2010). Numerical results indicate a significant outperformance of MIPGO over the state-of-the-art solution scheme, local linear approximation, and other alternative solution techniques in literature in terms of solution quality. PMID:27141126

  3. Shock wave reflection over convex and concave wedge

    NASA Astrophysics Data System (ADS)

    Kitade, M.; Kosugi, T.; Yada, K.; Takayama, Kazuyoshi

    2001-04-01

    It is well known that the transition criterion nearly agrees with the detachment criterion in the case of strong shocks, two-dimensional, and pseudosteady flow. However, when the shock wave diffracts over a wedge whose angle is below the detachment criterion, that is, in the domain of Mach reflection, precursory regular reflection (PRR) appears near the leading edge and as the shock wave propagates, the PRR is swept away by the overtaking corner signal (cs) that forces the transition to Mach reflection. It is clear that viscosity and thermal conductivity influences transition and the triple point trajectory. On the other hand, the reflection over concave and convex wedges is truly unsteady flow, and the effect of viscosity and thermal conductivity on transition and triple point trajectory has not been reported. This paper describes that influence of viscosity over convex and concave corners investigated both experiments and numerical simulations.

  4. Non-Concave Penalized Likelihood with NP-Dimensionality

    PubMed Central

    Fan, Jianqing; Lv, Jinchi

    2011-01-01

    Penalized likelihood methods are fundamental to ultra-high dimensional variable selection. How high dimensionality such methods can handle remains largely unknown. In this paper, we show that in the context of generalized linear models, such methods possess model selection consistency with oracle properties even for dimensionality of Non-Polynomial (NP) order of sample size, for a class of penalized likelihood approaches using folded-concave penalty functions, which were introduced to ameliorate the bias problems of convex penalty functions. This fills a long-standing gap in the literature where the dimensionality is allowed to grow slowly with the sample size. Our results are also applicable to penalized likelihood with the L1-penalty, which is a convex function at the boundary of the class of folded-concave penalty functions under consideration. The coordinate optimization is implemented for finding the solution paths, whose performance is evaluated by a few simulation examples and the real data analysis. PMID:22287795

  5. Entanglement criteria via concave-function uncertainty relations

    SciTech Connect

    Huang Yichen

    2010-07-15

    A general theorem as a necessary condition for the separability of quantum states in both finite and infinite dimensional systems, based on concave-function uncertainty relations, is derived. Two special cases of the general theorem are stronger than two known entanglement criteria based on the Shannon entropic uncertainty relation and the Landau-Pollak uncertainty relation, respectively; other special cases are able to detect entanglement where some famous entanglement criteria fail.

  6. Monotonicity and Logarithmic Concavity of Two Functions Involving Exponential Function

    ERIC Educational Resources Information Center

    Liu, Ai-Qi; Li, Guo-Fu; Guo, Bai-Ni; Qi, Feng

    2008-01-01

    The function 1 divided by "x"[superscript 2] minus "e"[superscript"-x"] divided by (1 minus "e"[superscript"-x"])[superscript 2] for "x" greater than 0 is proved to be strictly decreasing. As an application of this monotonicity, the logarithmic concavity of the function "t" divided by "e"[superscript "at"] minus "e"[superscript"(a-1)""t"] for "a"…

  7. Mixed convection heat transfer in concave and convex channels

    SciTech Connect

    Moukalled, F.; Doughan, A.; Acharya, S.

    1997-07-01

    Mixed convection heat transfer studies in the literature have been primarily confined to pipe and rectangular channel geometry's. In some applications, however, heat transfer in curved channels may be of interest (e.g., nozzle and diffuser shaped passages in HVAC systems, fume hoods, chimneys, bell-shaped or dome-shaped chemical reactors, etc.). A numerical investigation of laminar mixed convection heat transfer of air in concave and convex channels is presented. Six different channel aspects ratios (R/L = 1.04, 1.25, 2.5, 5, 10, and {infinity}) and five different values of Gr/Re{sup 2} (Gr/Re{sup 2} = 0, 0.1, 1, 3, 5) are considered. Results are displayed in terms of streamline and isotherm plots, velocity and temperature profiles, and local and average Nusselt number estimates. Numerical predictions reveal that compared to straight channels of equal height, concave channels of low aspect ratio have lower heat transfer at relatively low values of Gr/Re{sup 2} and higher heat transfer at high values of Gr/Re{sup 2}. When compared to straight channels of equal heated length, concave channels are always found to have lower heat transfer and for all values of Gr/Re{sup 2}. On the other hand, predictions for convex channels revealed enhancement in heat transfer compared to straight channels of equal height and/or equal heated length for all values of Gr/Re{sup 2}.

  8. STRONG ORACLE OPTIMALITY OF FOLDED CONCAVE PENALIZED ESTIMATION

    PubMed Central

    Fan, Jianqing; Xue, Lingzhou; Zou, Hui

    2014-01-01

    Folded concave penalization methods have been shown to enjoy the strong oracle property for high-dimensional sparse estimation. However, a folded concave penalization problem usually has multiple local solutions and the oracle property is established only for one of the unknown local solutions. A challenging fundamental issue still remains that it is not clear whether the local optimum computed by a given optimization algorithm possesses those nice theoretical properties. To close this important theoretical gap in over a decade, we provide a unified theory to show explicitly how to obtain the oracle solution via the local linear approximation algorithm. For a folded concave penalized estimation problem, we show that as long as the problem is localizable and the oracle estimator is well behaved, we can obtain the oracle estimator by using the one-step local linear approximation. In addition, once the oracle estimator is obtained, the local linear approximation algorithm converges, namely it produces the same estimator in the next iteration. The general theory is demonstrated by using four classical sparse estimation problems, i.e., sparse linear regression, sparse logistic regression, sparse precision matrix estimation and sparse quantile regression. PMID:25598560

  9. STRONG ORACLE OPTIMALITY OF FOLDED CONCAVE PENALIZED ESTIMATION.

    PubMed

    Fan, Jianqing; Xue, Lingzhou; Zou, Hui

    2014-06-01

    Folded concave penalization methods have been shown to enjoy the strong oracle property for high-dimensional sparse estimation. However, a folded concave penalization problem usually has multiple local solutions and the oracle property is established only for one of the unknown local solutions. A challenging fundamental issue still remains that it is not clear whether the local optimum computed by a given optimization algorithm possesses those nice theoretical properties. To close this important theoretical gap in over a decade, we provide a unified theory to show explicitly how to obtain the oracle solution via the local linear approximation algorithm. For a folded concave penalized estimation problem, we show that as long as the problem is localizable and the oracle estimator is well behaved, we can obtain the oracle estimator by using the one-step local linear approximation. In addition, once the oracle estimator is obtained, the local linear approximation algorithm converges, namely it produces the same estimator in the next iteration. The general theory is demonstrated by using four classical sparse estimation problems, i.e., sparse linear regression, sparse logistic regression, sparse precision matrix estimation and sparse quantile regression.

  10. Study of Unsteady Flows with Concave Wall Effect

    NASA Technical Reports Server (NTRS)

    Wang, Chi R.

    2003-01-01

    This paper presents computational fluid dynamic studies of the inlet turbulence and wall curvature effects on the flow steadiness at near wall surface locations in boundary layer flows. The time-stepping RANS numerical solver of the NASA Glenn-HT RANS code and a one-equation turbulence model, with a uniform inlet turbulence modeling level of the order of 10 percent of molecular viscosity, were used to perform the numerical computations. The approach was first calibrated for its predictabilities of friction factor, velocity, and temperature at near surface locations within a transitional boundary layer over concave wall. The approach was then used to predict the velocity and friction factor variations in a boundary layer recovering from concave curvature. As time iteration proceeded in the computations, the computed friction factors converged to their values from existing experiments. The computed friction factors, velocity, and static temperatures at near wall surface locations oscillated periodically in terms of time iteration steps and physical locations along the span-wise direction. At the upstream stations, the relationship among the normal and tangential velocities showed vortices effects on the velocity variations. Coherent vortices effect on the velocity components broke down at downstream stations. The computations also predicted the vortices effects on the velocity variations within a boundary layer flow developed along a concave wall surface with a downstream recovery flat wall surface. It was concluded that the computational approach might have the potential to analyze the flow steadiness in a turbine blade flow.

  11. Highlights, disparity, and perceived gloss with convex and concave surfaces.

    PubMed

    Kerrigan, Iona S; Adams, Wendy J

    2013-01-04

    Glossy and matte objects can be differentiated using specular highlights: bright patches in the retinal image produced when light rays are reflected regularly from smooth surfaces. However, bright patches also occur on matte objects, due to local illumination or reflectance changes. Binocular vision provides information that could distinguish specular highlights from other luminance discontinuities; unlike surface markings, specular highlights lie not at the surface depth, but "float" in front of concave surfaces and behind convex ones. We ask whether observers implicitly understand and exploit the peculiarities of specular geometry for gloss and shape perception. Our participants judged the glossiness and shape of curved surfaces that included specular highlights at various depths. Observers demonstrated substantial deviations from a full geometric model of specular reflection. Concave surfaces appeared glossy both when highlights lay in front of and (incorrectly) behind the surface. Failings in the interpretation of monocular highlights were also apparent. Highlight disparity had no effect on shape perception. However, the perceived gloss of convex surfaces did follow geometric constraints: only highlights at appropriate depths produced high gloss ratings. We suggest, in contrast with previous work, that the visual system invokes simple heuristics as gloss indicators to accommodate complex reflections and inter-reflections that occur particularly inside concavities.

  12. Development of the tongue coating analyzer based on concave grating monochrometer and virtual instrument

    NASA Astrophysics Data System (ADS)

    Ren, Zhong; Liu, Guodong; Zeng, Lvming; Huang, Zhen; Zeng, Wenping

    2010-10-01

    The tongue coating diagnosis is an important part in tongue diagnosis of traditional Chinese medicine (TCM).The change of the thickness and color of the tongue coating can reflect the pathological state for the patient. By observing the tongue coating, a Chinese doctor can determine the nature or severity of disease. Because some limitations existed in the tongue diagnosis method of TCM and the method based on the digital image processing, a novel tongue coating analyzer(TCA) based on the concave grating monochrometer and virtual instrument is developed in this paper. This analyzer consists of the light source system, check cavity, optical fiber probe, concave grating monochrometer, spectrum detector system based on CCD and data acquisition (DAQ) card, signal processing circuit system, computer and data analysis software based on LabVIEW, etc. Experimental results show that the novel TCA's spectral range can reach 300-1000 nm, its wavelength resolution can reach 1nm, and this TCA uses the back-split-light technology and multi-channel parallel analysis. Compared with the TCA based on the image processing technology, this TCA has many advantages, such as, compact volume, simpler algorithm, faster processing speed, higher accuracy, cheaper cost and real-time handle data and display the result, etc. Therefore, it has the greatly potential values in the fields of the tongue coating diagnosis for TCM.

  13. Comparison of generic force fields for packing of concave molecules

    NASA Astrophysics Data System (ADS)

    Del Regno, Annalaura; Siperstein, Flor R.

    2014-09-01

    Organic molecules of intrinsic microporosity (OMIMs) are a new class of highly concave molecules, designed to pack inefficiently and create microporous materials. In this work, OMIM-1 was described with full atomistic models using Dreiding, optimised potentials for liquid simulations (OPLS) and Universal force fields to recognise the features enhanced by each force field and assess their ability in representing the structural properties of this new class of materials. In addition, argon adsorption isotherms were modelled to determine the features observed in the isotherm generated by each force field, for future comparison with experimental data.

  14. Jet printing of convex and concave polymer micro-lenses.

    PubMed

    Blattmann, M; Ocker, M; Zappe, H; Seifert, A

    2015-09-21

    We describe a novel approach for fabricating customized convex as well as concave micro-lenses using substrates with sophisticated pinning architecture and utilizing a drop-on-demand jet printer. The polymeric lens material deposited on the wafer is cured by UV light irradiation yielding lenses with high quality surfaces. Surface shape and roughness of the cured polymer lenses are characterized by white light interferometry. Their optical quality is demonstrated by imaging an USAF1951 test chart. The evaluated modulation transfer function is compared to Zemax simulations as a benchmark for the fabricated lenses.

  15. Large-eddy simulation of a boundary layer with concave streamwise curvature

    NASA Technical Reports Server (NTRS)

    Lund, Thomas S.

    1994-01-01

    Turbulence modeling continues to be one of the most difficult problems in fluid mechanics. Existing prediction methods are well developed for certain classes of simple equilibrium flows, but are still not entirely satisfactory for a large category of complex non-equilibrium flows found in engineering practice. Direct and large-eddy simulation (LES) approaches have long been believed to have great potential for the accurate prediction of difficult turbulent flows, but the associated computational cost has been prohibitive for practical problems. This remains true for direct simulation but is no longer clear for large-eddy simulation. Advances in computer hardware, numerical methods, and subgrid-scale modeling have made it possible to conduct LES for flows or practical interest at Reynolds numbers in the range of laboratory experiments. The objective of this work is to apply ES and the dynamic subgrid-scale model to the flow of a boundary layer over a concave surface.

  16. Directable weathering of concave rock using curvature estimation.

    PubMed

    Jones, Michael D; Farley, McKay; Butler, Joseph; Beardall, Matthew

    2010-01-01

    We address the problem of directable weathering of exposed concave rock for use in computer-generated animation or games. Previous weathering models that admit concave surfaces are computationally inefficient and difficult to control. In nature, the spheroidal and cavernous weathering rates depend on the surface curvature. Spheroidal weathering is fastest in areas with large positive mean curvature and cavernous weathering is fastest in areas with large negative mean curvature. We simulate both processes using an approximation of mean curvature on a voxel grid. Both weathering rates are also influenced by rock durability. The user controls rock durability by editing a durability graph before and during weathering simulation. Simulations of rockfall and colluvium deposition further improve realism. The profile of the final weathered rock matches the shape of the durability graph up to the effects of weathering and colluvium deposition. We demonstrate the top-down directability and visual plausibility of the resulting model through a series of screenshots and rendered images. The results include the weathering of a cube into a sphere and of a sheltered inside corner into a cavern as predicted by the underlying geomorphological models.

  17. Scaling relationships and concavity of small valley networks on Mars

    NASA Astrophysics Data System (ADS)

    Penido, Julita C.; Fassett, Caleb I.; Som, Sanjoy M.

    2013-01-01

    Valley networks are widely interpreted as the preserved erosional record of water flowing across the martian surface. The manner in which valley morphometric properties scale with drainage area has been widely examined on Earth. Earlier studies assessing these properties on Mars have suggested that martian valleys are morphometrically distinct from those on Earth. However, these earlier measurements were generally made on large valley systems because of the limited topographic data available. In this study, we determine the scaling properties of valley networks at smaller scales than have been previously assessed, using digital elevation models from the High Resolution Stereo Camera (HRSC). We find a Hack's law exponent of 0.74, larger than on Earth, and our measurements also reveal that individual small valleys have concave up, concave down, and quasi-linear longitudinal profiles, consistent with earlier studies of dissected terrain on Mars. However, for many valleys, widths are observed to increase downstream similarly to how they scale in terrestrial channels. The similarities and differences between valley networks on Mars and Earth are consistent with the idea that valleys on Mars are comparatively immature, and precipitation was a likely mechanism for delivering water to these networks.

  18. Head rice rate measurement based on concave point matching

    NASA Astrophysics Data System (ADS)

    Yao, Yuan; Wu, Wei; Yang, Tianle; Liu, Tao; Chen, Wen; Chen, Chen; Li, Rui; Zhou, Tong; Sun, Chengming; Zhou, Yue; Li, Xinlu

    2017-01-01

    Head rice rate is an important factor affecting rice quality. In this study, an inflection point detection-based technology was applied to measure the head rice rate by combining a vibrator and a conveyor belt for bulk grain image acquisition. The edge center mode proportion method (ECMP) was applied for concave points matching in which concave matching and separation was performed with collaborative constraint conditions followed by rice length calculation with a minimum enclosing rectangle (MER) to identify the head rice. Finally, the head rice rate was calculated using the sum area of head rice to the overall coverage of rice. Results showed that bulk grain image acquisition can be realized with test equipment, and the accuracy rate of separation of both indica rice and japonica rice exceeded 95%. An increase in the number of rice did not significantly affect ECMP and MER. High accuracy can be ensured with MER to calculate head rice rate by narrowing down its relative error between real values less than 3%. The test results show that the method is reliable as a reference for head rice rate calculation studies.

  19. Roll-cell structure in a concave turbulent boundary layer

    NASA Astrophysics Data System (ADS)

    Barlow, R. S.; Johnston, J. P.

    1985-01-01

    Flow visualization by laser-induced fluorescence and velocity profiles obtained by laser-doppler anemometry are used to study the structure of roll cells in a turbulent boundary layer on a concave surface. Vortex generators are used to lock the roll cells into stable spanwise locations, and the resulting flow is compared to the natural flow, in which the roll cells wander about, merge, separate, appear and disappear. In both cases the spanwise-average friction coefficient, C(f), is increased by about 40 percent relative to flat-plate values. A significant lag in the response of C(f) to the onset of curvature suggests that the large-scale eddy structure in the boundary layer must be modified before the full effect on skin friction is seen. Mean velocity profiles, which extend as far into the sublayer as Y(+) = 1.5, demonstrate that strong concave curvature produces a negative wake. This result confirms the visual evidence of vigorous mixing which accompanies larger than normal length scales across the boundary layer.

  20. The concave river long profile: a morphodynamic steady state?

    NASA Astrophysics Data System (ADS)

    Blom, A.

    2011-12-01

    By definition, a morphodynamic steady state is governed by a spatially constant sediment transport rate. As the sediment transport rate is a function of shear stress associated with skin friction, the morphodynamic steady state has been considered to be governed by a spatially constant bed slope. For this reason, the typical concave river long profile has been considered to be a quasi-steady state. The river's steady state has been considered to be one with a spatially constant bed slope, with tributaries inducing a stepwise decrease in bed slope in streamwise direction. Yet, for the sediment transport rate to be spatially constant, it rather is the product of water surface slope and water depth associated with skin friction that needs to be constant. This implies that physical mechanisms that induce streamwise variation in the sediment transport rate can be compensated by a streamwise variation in bed slope so as to guarantee a spatially constant sediment transport rate. Following the river course, such physical mechanisms can be bedrock exposure, partial transport, and a spatially lagging bedform growth. At locations where tributaries increase the water discharge, the above mechanisms cause the river bed profile to be upward concave over a significant reach. At bifucations or at locations where river widening prevails, the river bed profile is upward convex.

  1. Head rice rate measurement based on concave point matching

    PubMed Central

    Yao, Yuan; Wu, Wei; Yang, Tianle; Liu, Tao; Chen, Wen; Chen, Chen; Li, Rui; Zhou, Tong; Sun, Chengming; Zhou, Yue; Li, Xinlu

    2017-01-01

    Head rice rate is an important factor affecting rice quality. In this study, an inflection point detection-based technology was applied to measure the head rice rate by combining a vibrator and a conveyor belt for bulk grain image acquisition. The edge center mode proportion method (ECMP) was applied for concave points matching in which concave matching and separation was performed with collaborative constraint conditions followed by rice length calculation with a minimum enclosing rectangle (MER) to identify the head rice. Finally, the head rice rate was calculated using the sum area of head rice to the overall coverage of rice. Results showed that bulk grain image acquisition can be realized with test equipment, and the accuracy rate of separation of both indica rice and japonica rice exceeded 95%. An increase in the number of rice did not significantly affect ECMP and MER. High accuracy can be ensured with MER to calculate head rice rate by narrowing down its relative error between real values less than 3%. The test results show that the method is reliable as a reference for head rice rate calculation studies. PMID:28128315

  2. Transversal stability of the bouncing ball on a concave surface

    NASA Astrophysics Data System (ADS)

    Chastaing, J.-Y.; Pillet, G.; Taberlet, N.; Géminard, J.-C.

    2015-05-01

    A ball bouncing repeatedly on a vertically vibrating surface constitutes the famous "bouncing ball" problem, a nonlinear system used in the 1980s, and still in use nowadays, to illustrate the route to chaos by period doubling. In experiments, in order to avoid the ball escape that would be inevitable with a flat surface, a concave lens is often used to limit the horizontal motion. However, we observe experimentally that the system is not stable. The ball departs from the system axis and exhibits a pendular motion in the permanent regime. We propose theoretical arguments to account for the decrease of the growth rate and of the asymptotic-size of the trajectory when the frequency of the vibration is increased. The instability is very sensitive to the physics of the contacts, which makes it a potentially interesting way to study the collisions rules, or to test the laws used in numerical studies of granular matter.

  3. Pentiptycene-based concave NHC-metal complexes.

    PubMed

    Savka, Roman; Foro, Sabine; Plenio, Herbert

    2016-07-05

    The reaction of 1-amino,4-hydroxy-pentiptycene with diacetyl or acenaphthene-1,2-dione gave the respective diimines, followed by alkylation of the hydroxyl groups, and cyclization of the alkylated diimines to the respective bispentiptycene-imidazolium salts NHC·HCl. The azolium salts, being precursors to N-heterocyclic carbenes, were converted into metal complexes [(NHC)MX] (MX = CuI, AgCl, AuCl) and [(NHC)IrCl(cod)] and [(NHC)IrCl(CO)2] in good yields. In the solid state [(NHC)AgCl] displays a bowl-shaped structure of the ligand with the metal center buried within the concave unit.

  4. Transient river response, captured by channel steepness and its concavity

    NASA Astrophysics Data System (ADS)

    Vanacker, Veerle; von Blanckenburg, Friedhelm; Govers, Gerard; Molina, Armando; Campforts, Benjamin; Kubik, Peter W.

    2015-01-01

    Mountain rivers draining tropical regions are known to be great conveyor belts carrying efficiently more than half of the global sediment flux to the oceans. Many tropical mountain areas are located in tectonically active belts where the hillslope and stream channel morphology are rapidly evolving in response to changes in base level. Here, we report basin-wide denudation rates for an east-west transect through the tropical Andes. Hillslope and channel morphology vary systematically from east to west, reflecting the transition from high relief, strongly dissected topography in the escarpment zones into relatively low relief topography in the inter-Andean valley. The spatial pattern of differential denudation rates reflects the transient adjustment of the landscape to rapid river incision following tectonic uplift and river diversion. In the inter-Andean valley, upstream of the wave of incision, slopes and river channels display a relatively smooth, concave-up morphology and denudation rates (time scale of 104-105 a) are consistently low (3 to 200 mm/ka). In contrast, slopes and river channels of rejuvenated basins draining the eastern cordillera are steep to very steep; and the studied drainage basins show a wide range of denudation rate values (60 to 400 mm/ka) that increase systematically with increasing basin mean slope gradient, channel steepness, and channel convexity. Drainage basins that are characterised by strong convexities in their river longitudinal profiles systematically have higher denudation rates. As such, this is one of the first studies that provides field-based evidence of a correlation between channel concavity and basin mean denudation rates, consistent with process-based fluvial incision models.

  5. Reproducible Construction of Surface Tension-Mediated Honeycomb Concave Microwell Arrays for Engineering of 3D Microtissues with Minimal Cell Loss

    PubMed Central

    Lee, GeonHui; Lee, JaeSeo; Oh, HyunJik; Lee, SangHoon

    2016-01-01

    The creation of engineered 3D microtissues has attracted prodigious interest because of the fact that this microtissue structure is able to mimic in vivo environments. Such microtissues can be applied extensively in the fields of regenerative medicine and tissue engineering, as well as in drug and toxicity screening. Here, we develop a novel method of fabricating a large number of dense honeycomb concave microwells via surface tension-mediated self-construction. More specifically, in order to control the curvature and shape of the concavity in a precise and reproducible manner, a custom-made jig system was designed and fabricated. By applying a pre-set force using the jig system, the shape of the honeycomb concave well was precisely and uniformly controlled, despite the fact that wells were densely packed. The thin wall between the honeycomb wells enables the minimization of cell loss during the cell-seeding process. To evaluate the performance of the honeycomb microwell array, rat hepatocytes were seeded, and spheroids were successfully formed with uniform shape and size. Liver-specific functions such as albumin secretion and cytochrome P450 were subsequently analyzed. The proposed method of fabricating honeycomb concave wells is cost-effective, simple, and reproducible. The honeycomb well array can produce multiple spheroids with minimal cell loss, and can lead to significant contributions in tissue engineering and organ regeneration. PMID:27513567

  6. Reproducible Construction of Surface Tension-Mediated Honeycomb Concave Microwell Arrays for Engineering of 3D Microtissues with Minimal Cell Loss.

    PubMed

    Lee, GeonHui; Lee, JaeSeo; Oh, HyunJik; Lee, SangHoon

    2016-01-01

    The creation of engineered 3D microtissues has attracted prodigious interest because of the fact that this microtissue structure is able to mimic in vivo environments. Such microtissues can be applied extensively in the fields of regenerative medicine and tissue engineering, as well as in drug and toxicity screening. Here, we develop a novel method of fabricating a large number of dense honeycomb concave microwells via surface tension-mediated self-construction. More specifically, in order to control the curvature and shape of the concavity in a precise and reproducible manner, a custom-made jig system was designed and fabricated. By applying a pre-set force using the jig system, the shape of the honeycomb concave well was precisely and uniformly controlled, despite the fact that wells were densely packed. The thin wall between the honeycomb wells enables the minimization of cell loss during the cell-seeding process. To evaluate the performance of the honeycomb microwell array, rat hepatocytes were seeded, and spheroids were successfully formed with uniform shape and size. Liver-specific functions such as albumin secretion and cytochrome P450 were subsequently analyzed. The proposed method of fabricating honeycomb concave wells is cost-effective, simple, and reproducible. The honeycomb well array can produce multiple spheroids with minimal cell loss, and can lead to significant contributions in tissue engineering and organ regeneration.

  7. Facile synthesis of concave gold nanoplates in hexagonal liquid crystal made of SDS/water system.

    PubMed

    Wang, Luyan; Wu, Xinzhou; Li, Xiaonan; Wang, Li; Pei, Meishan; Tao, Xutang

    2010-11-28

    Concave gold nanoplates are obtained in hexagonal liquid crystal (LLC) made of SDS (sodium dodecyl sulfate)/glycine/HAuCl(4) aqueous solution system where glycine plays the key role. All plates are single-crystals, characterized by {111} facets, with concave centers of regular hexagonal or triangular shapes, and with better electrocatalytic activity than gold nanoplates.

  8. The Role of Definition in Students' Understanding with Particular Reference to the Concavity of a Function

    ERIC Educational Resources Information Center

    Ureyen, Mehmet

    2006-01-01

    In this study, the effect of different definitions of concavity on students' understanding was investigated. Students enrolled in the calculus-II course in the science and engineering faculties in Anadolu University, Turkey were divided into two groups and each group was given a different definition of concavity. At the end of the study, both…

  9. Optimal Impeller Clearance for a Dual Stirred Unbaffled Tank with a Concave Blade Impeller

    NASA Astrophysics Data System (ADS)

    Devi, T. T.; Kumar, B.

    2016-07-01

    An experimental investigation of unbaffled stirred tanks is carried out with the use of a dual concave blade impeller to evaluate the mass transfer coefficient, power number, and vortex depth. The effect of the impeller clearance on mass transfer is analyzed to estimate the optimal impeller clearance for lower and upper impellers. It is found that the lower impeller positioned at 0.25 of the tank diameter with the clearance between the lower and upper impellers equal to 0.38 of the tank diameter gives the maximum mass transfer coefficient. A comparison with the results for dual Rushton and Rushton-concave impellers at the optimal clearance shows that the concave-concave impellers are most efficient. The scale-up criteria for optimal, geometrically similar systems of unbaffled stirred tanks with a dual concave impeller are proposed.

  10. Measurement of the configuration of a concave surface by the interference of reflected light

    NASA Technical Reports Server (NTRS)

    Kumazawa, T.; Sakamoto, T.; Shida, S.

    1985-01-01

    A method whereby a concave surface is irradiated with coherent light and the resulting interference fringes yield information on the concave surface is described. This method can be applied to a surface which satisfies the following conditions: (1) the concave face has a mirror surface; (2) the profile of the face is expressed by a mathematical function with a point of inflection. In this interferometry, multilight waves reflected from the concave surface interfere and make fringes wherever the reflected light propagates. Interference fringe orders. Photographs of the fringe patterns for a uniformly loaded thin silicon plate clamped at the edge are shown experimentally. The experimental and the theoretical values of the maximum optical path difference show good agreement. This simple method can be applied to obtain accurate information on concave surfaces.

  11. From concave to convex: capillary bridges in slit pore geometry.

    PubMed

    Broesch, David J; Frechette, Joelle

    2012-11-06

    We investigate the morphological evolution of nonaxisymmetric capillary bridges in slit-pore geometry as the height of the pore and aspect ratio of the bridge are varied. The liquid bridges are formed between two hydrophobic surfaces patterned with hydrophilic strips. The aspect ratio of the capillary bridges (length/width) is varied from 2.5 to 120 by changing the separation between the surfaces, the width of the strips, or the fluid volume. As the bridge height is increased, the aspect ratio decreases and we observe a large increase in the mean curvature of the bridge. More specifically, the following counterintuitive result is observed: the mean curvature of the bridges changes sign and goes from negative (concave bridge) to positive (convex bridge) when the height is increased at constant volume. These experimental observations are in quantitative agreement with Surface Evolver simulations. Scaling shows a collapse of the data indicating that this transition in the sign of the Laplace pressure is universal for capillary bridges with high aspect ratios. Finally, we show that the morphology diagrams obtained from our 3D analysis are considerably different from those expected from a 2D analysis.

  12. Hydrogen adsorption-mediated synthesis of concave Pt nanocubes and their enhanced electrocatalytic activity

    NASA Astrophysics Data System (ADS)

    Lu, Bang-An; Du, Jia-Huan; Sheng, Tian; Tian, Na; Xiao, Jing; Liu, Li; Xu, Bin-Bin; Zhou, Zhi-You; Sun, Shi-Gang

    2016-06-01

    Concave nanocubes are enclosed by high-index facets and have negative curvature; they are expected to have enhanced reactivity, as compared to nanocubes with flat surfaces. Herein, we propose and demonstrate a new strategy for the synthesis of concave Pt nanocubes with {hk0} high-index facets, by using a hydrogen adsorption-mediated electrochemical square-wave potential method. It was found that Pt atoms prefer to deposit on edge sites rather than terrace sites on Pt surfaces with intensive hydrogen adsorption, resulting in the formation of concave structures. The as-prepared concave Pt nanocubes exhibit enhanced catalytic activity and stability towards oxidation of ethanol and formic acid in acidic solutions, compared to commercial Pt/C catalysts.Concave nanocubes are enclosed by high-index facets and have negative curvature; they are expected to have enhanced reactivity, as compared to nanocubes with flat surfaces. Herein, we propose and demonstrate a new strategy for the synthesis of concave Pt nanocubes with {hk0} high-index facets, by using a hydrogen adsorption-mediated electrochemical square-wave potential method. It was found that Pt atoms prefer to deposit on edge sites rather than terrace sites on Pt surfaces with intensive hydrogen adsorption, resulting in the formation of concave structures. The as-prepared concave Pt nanocubes exhibit enhanced catalytic activity and stability towards oxidation of ethanol and formic acid in acidic solutions, compared to commercial Pt/C catalysts. Electronic supplementary information (ESI) available: Details of DFT calculation, SEM images of concave Pt nanocubes, mass activity and stability characterization of the catalysts. See DOI: 10.1039/c6nr02349e

  13. The morphology of graphene on a non-developable concave substrate

    NASA Astrophysics Data System (ADS)

    Chen, Yuli; Ma, Yong; Wang, Shengtao; Zhou, Yanguang; Liu, Hao

    2016-01-01

    The performances of graphene sheet in micro- and nano-electronics and devices are significantly affected by its morphology, which depends on the surface features of the supporting substrate. The substrates with non-developable concave surface are widely used with graphene sheet in applications but rarely studied. Therefore, a theoretical model is established based on the energy analysis to explain the adhesion mechanisms and predict the morphology of the graphene sheet on a non-developable concave surface. Four different morphologies of the graphene sheet are revealed, and the critical conditions are established to predict which morphology the graphene/substrate system belongs to. For the monolayer graphene sheets much larger than the concave of substrate, the final equilibrium morphology is dominated by the half cone angle of the concave. The graphene sheet conforms completely to the SiO2 substrate if the half cone angle is less than 27.5 ° and spans over the concave if the angel is larger than 27.5 ° . For graphene sheets smaller than the concave, they fall into the concave and the final morphology depends only on the ratio of graphene radius to concave radius. The monolayer graphene sheet conforms to the concave if the radius ratio is less than 0.51 and wrinkles if the ratio is larger than 0.51. The theoretical results are verified by a series of molecular dynamics simulations on various graphene/substrate systems. This work can provide guidelines to design high quality graphene-coated functional materials and devices, and can offer criterion for graphene-derived nano-electronics and nano-sensors.

  14. Tunable far-field acoustic imaging by two-dimensional sonic crystal with concave incident surface

    NASA Astrophysics Data System (ADS)

    Shen, Feng-Fu; Lu, Dan-Feng; Zhu, Hong-Wei; Ji, Chang-Ying; Shi, Qing-Fan

    2017-01-01

    An additional concave incident surface comprised of two-dimensional (2D) sonic crystals (SCs) is employed to tune the acoustic image in the far-field region. The tunability is realized through changing the curvature of the concave surface. To explain the tuning mechanism, a simple ray-trace analysis is demonstrated based on the wave-beam negative refractive law. Then, a numerical confirmation is carried out. Results show that both the position and the intensity of the image can be tuned by the introduced concave surface.

  15. Research on adaptive temperature control in sound field induced by self-focused concave spherical transducer.

    PubMed

    Hu, Jiwen; Qian, Shengyou; Ding, Yajun

    2010-05-01

    Temperature control of hyperthermia treatments is generally implemented with multipoint feedback system comprised of phased-array transducer, which is complicated and high cost. Our simulations to the acoustic field induced by a self-focused concave spherical transducer (0.5MHz, 9cm aperture width, 8.0cm focal length) show that the distribution of temperature can keep the same "cigar shape" in the focal region during ultrasound insonation. Based on the characteristic of the temperature change, a two-dimensional model of a "cigar shape" tumor is designed and tested through numerical simulation. One single-point on the border of the "cigar shape" tumor is selected as the control target and is controlled at the temperature of 43 degrees C by using a self-tuning regulator (STR). Considering the nonlinear effects of biological medium, an accurate state-space model obtained via the finite Fourier integral transformation to the bioheat equation is presented and used for calculating temperature. Computer simulations were performed with the perfusion rates of 2.0kg/(m(3)s) and 4.5kg/(m(3)s) to the different targets, it was found that the temperatures on the border of the "cigar shape" tumor can achieve the desired temperature of 43 degrees C by control of one single-point. A larger perfusion rate requires a higher power output to obtain the same temperature elevation under the same insonation time and needs a higher cost for compensating the energy loss carried away by blood flow after steady state. The power output increases with the controlled region while achieving the same temperature at the same time. Especially, there is no overshoot during temperature elevation and no oscillation after steady state. The simulation results demonstrate that the proposed approach may offers a way for obtaining a single-point, low-cost hyperthermia system.

  16. Design and fabrication of concave-convex lens for head mounted virtual reality 3D glasses

    NASA Astrophysics Data System (ADS)

    Deng, Zhaoyang; Cheng, Dewen; Hu, Yuan; Huang, Yifan; Wang, Yongtian

    2015-08-01

    As a kind of light-weighted and convenient tool to achieve stereoscopic vision, virtual reality glasses are gaining more popularity nowadays. For these glasses, molded plastic lenses are often adopted to handle both the imaging property and the cost of massive production. However, the as-built performance of the glass depends on both the optical design and the injection molding process, and maintaining the profile of the lens during injection molding process presents particular challenges. In this paper, optical design is combined with processing simulation analysis to obtain a design result suitable for injection molding. Based on the design and analysis results, different experiments are done using high-quality equipment to optimize the process parameters of injection molding. Finally, a single concave-convex lens is designed with a field-of-view of 90° for the virtual reality 3D glasses. The as-built profile error of the glass lens is controlled within 5μm, which indicates that the designed shape of the lens is fairly realized and the designed optical performance can thus be achieved.

  17. Shadow-related concavity-convexity inversions reveal a very basic tolerance for impossible shadows.

    PubMed

    Casati, Roberto

    2014-01-01

    The stimuli traditionally used for demonstrating shadow-related concavity-convexity inversions reveal a very basic tolerance for impossible shadows-namely, self shadows do not induce a visual request for geometrically mandatory cast shadows.

  18. High voltage photo-switch package module having encapsulation with profiled metallized concavities

    DOEpatents

    Sullivan, James S; Sanders, David M; Hawkins, Steven A; Sampayan, Stephen A

    2015-05-05

    A photo-conductive switch package module having a photo-conductive substrate or wafer with opposing electrode-interface surfaces metalized with first metallic layers formed thereon, and encapsulated with a dielectric encapsulation material such as for example epoxy. The first metallic layers are exposed through the encapsulation via encapsulation concavities which have a known contour profile, such as a Rogowski edge profile. Second metallic layers are then formed to line the concavities and come in contact with the first metal layer, to form profiled and metalized encapsulation concavities which mitigate enhancement points at the edges of electrodes matingly seated in the concavities. One or more optical waveguides may also be bonded to the substrate for coupling light into the photo-conductive wafer, with the encapsulation also encapsulating the waveguides.

  19. Heat transfer characteristics of a single circular air jet impinging on a concave hemispherical shell

    NASA Technical Reports Server (NTRS)

    Livingood, J. N. B.; Gauntner, J. W.

    1973-01-01

    An experimental study was made of the local and average heat-transfer characteristics of a single turbulent air jet impinging on the concave surface of a hemisphere. Correlations were developed for expressing the effects of a number of dimensionless variables on the local and average Nusselt numbers. Results of the present study are compared with those from a similar study concerning a concave surface of a semicylindrical shell.

  20. An experimental investigation of the supersonic turbulent boundary layer subjected to concave curvature

    NASA Astrophysics Data System (ADS)

    Wang, Qian-cheng; Wang, Zhen-guo; Zhao, Yu-xin

    2016-09-01

    By employing particle image velocimetry, the response of a Mach 2.95 turbulent boundary layer to the concave curvature is experimentally investigated. The radius of the concave wall is 350 mm, and the turning angle is 20∘. Logarithmic law is well preserved in the profile of streamwise velocity at all streamwise positions despite the impact of curvature. The varying trend of principal strain rate is found to be different at different heights within the boundary layer, which cannot be explained by the suggestion given by former researchers. Based on the three-layer model proposed in this paper, distribution of the principal strain rate is carefully analyzed. The streamwise increase of wall friction is suggested to be brought by the increase of velocity gradient in the thin subsonic layer. Increases of the static temperature and the related sound speed are responsible for that. Larger correlated turbulent motions could be introduced by the concave curvature. The probability density histograms of streamwise velocity reveal that the large scale hairpin packets are statistically well organized. The concave curvature is found to have the potential of reinforcing the organization, which explains the increase of turbulent level in the supersonic concave boundary layer.

  1. Light extraction efficiency enhancement of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures.

    PubMed

    Ee, Yik-Khoon; Kumnorkaew, Pisist; Arif, Ronald A; Tong, Hua; Gilchrist, James F; Tansu, Nelson

    2009-08-03

    Improvement of light extraction efficiency of InGaN light emitting diodes (LEDs) using polydimethylsiloxane (PDMS) concave microstructures arrays was demonstrated. The size effect of the concave microstructures on the light extraction efficiency of III-Nitride LEDs was studied. Depending on the size of the concave microstructures, ray tracing simulations show that the use of PDMS concave microstructures arrays can lead to increase in light extraction efficiency of InGaN LEDs by 1.5 to 2.0 times. Experiments utilizing 2.0 micron thick PDMS with 1.0 micron diameter of the PDMS concave microstructures arrays demonstrated 1.70 times improvement in light extraction efficiency, which is consistent with improvement of 1.77 times predicted from simulation. The enhancement in light extraction efficiency is attributed to increase in effective photon escape cone due to PDMS concave microstructures arrays.

  2. Concave Rhombic Dodecahedral Au Nanocatalyst with Multiple High-Index Facets for CO2 Reduction.

    PubMed

    Lee, Hye-Eun; Yang, Ki Dong; Yoon, Sang Moon; Ahn, Hyo-Yong; Lee, Yoon Young; Chang, Hyejin; Jeong, Dae Hong; Lee, Yoon-Sik; Kim, Mi Young; Nam, Ki Tae

    2015-08-25

    A concave rhombic dodecahedron (RD) gold nanoparticle was synthesized by adding 4-aminothiophenol (4-ATP) during growth from seeds. This shape is enclosed by stabilized facets of various high-indexes, such as (331), (221), and (553). Because it is driven thermodynamically and stabilized by 4-ATP ligands, the concave RD maintains its structure over a few months, even after rigorous electrochemical reactions. We discussed the mechanism of the shape evolution controlled by 4-ATP and found that both the binding energy of Au-S and the aromatic geometry of 4-ATP are major determinants of Au atom deposition during growth. As a possible application, we demonstrated that the concave RD exhibits superior electrocatalytic performance for the selective conversion of CO2 to CO in aqueous solution.

  3. Binding to phosphatidyl serine membranes causes a conformational change in the concave face of annexin I.

    PubMed Central

    de la Fuente, M; Ossa, C G

    1997-01-01

    Recent studies have revealed that binding of annexin I to phospholipids induces the formation of a second phospholipid binding site. It is shown that the N terminus on the concave side of membrane-bound annexin I is cleaved much faster by trypsin or cathepsin than the N terminus of the free protein. The reactivity of the unique disulfide bond located near the concave face was similarly increased by membrane binding. These results demonstrate that Ca(2+)-dependent membrane binding induces a conformational change on the concave side of the annexin I molecule and support the notion that this face of the molecule may contribute to the formation of the secondary membrane-binding site. Images FIGURE 1 FIGURE 5 PMID:8994623

  4. Micro-displacement sensor with multimode fused coupler and concave mirror

    NASA Astrophysics Data System (ADS)

    Harun, S. W.; Yasin, M.; Ahmad, H.

    2011-04-01

    Fiber optic displacement sensor is demonstrated using a multimode fused coupler probe and a concave mirror target. It is observed that a focal length of the concave mirror make a significant influence to the displacement response, which illustrates three linear slopes with the second slope peaks at the position that is in vicinity of two times of the focal length. The highest sensitivity of 0.56 mV/mm is obtained with an infinity focal length and it is decreased as the focal length of the concave mirror decreases. The widest linear range of approximately 3.3 mm is observed in the third slope region with focal length of 6.0 mm. The highest linear range obtained with the use of 50:50 coupler.

  5. Convex and concave successions of power-law decays in small-angle scattering

    NASA Astrophysics Data System (ADS)

    Anitas, E. M.

    2016-08-01

    The small-angle scattering (SAS) structure factor from a new model of a 3D deterministic fractal in which the relative positions and the number of structural units vary with fractal iteration number is calculated. It is shown that, depending on the relative positions of scattering units inside the fractal, we can obtain various types of power-law successions, such as: convex/concave - when the absolute value of the scattering exponent of the first power-law decay is higher/smaller than that of the subsequent power- law decay, or any combination of them (i.e. convex-concave or concave-convex). The obtained results can explain experimental SAS (neutron or X-rays) data which are characterized by a succession of power-law decays of arbitrary length.

  6. Simulation of sound field in a tissue medium generated by a concave spherically annular transducer.

    PubMed

    Qian, Shengyou; Kamakura, Tomoo; Akiyama, Masahiko

    2006-12-22

    The concave spherically annular transducer is regarded as a negative and a positive concave spherical transducer, and the spheroidal beam equation is used to simulate the linear and nonlinear sound field in a tissue medium generated by this transducer. It is found that the acoustic focus of the ring does not coincide with the acoustic focus of its central part. If the width of the ring increases, its acoustic focus will move toward the geometric focus and the amplitudes of nonlinear harmonics will increase obviously. If there are several coaxial rings placed on the concave spherical surface, more than one peak will appear along the axial direction for the fundamental, and high harmonics focus better. The distribution of sound field will change with the number and the excited signals of rings, so it maybe is a potential approach to treat locally big tumors.

  7. Cone Quasi-Concave Multi-Objective Programming Theory and Dominance Cone Constructions.

    DTIC Science & Technology

    1988-08-01

    4 Cone Quasi-Concave Multi-Objective Prog ramm in(I Theory and Dominance Cone Constructions by A. Chames Z. M. Huang J. J. Rousseau 0. B. Sun 0. L...Report 606 Cone Quasi-Concave Multi-Objective Programming: Theory and Dominance Cone Constructions by A. Chames Z. M. Huang J. J. Rousseau D. B. Sun...permitted for any purpose of the U.S. Govemement. Tr% C CENTER FOR CYBERNETIC STUDIES cV- A. Chames , Director V 3 D 1 College of Business Administration

  8. Metacoatings for wavelength-scale, high-numerical-aperture plano-concave focusing lenses

    NASA Astrophysics Data System (ADS)

    Naserpour, Mahin; Zapata-Rodríguez, Carlos J.; Díaz-Aviñó, Carlos; Hashemi, Mahdieh

    2016-10-01

    We design plano-concave silicon lenses with coupled gradient-index plasmonic metacoatings for ultrawide apertured focusing utilizing a reduced region of $\\sim 20 \\lambda^2$. The anomalous refraction induced in the planar input side of the lens and in the boundary of the wavelength-scale focal region boosts the curvature of the emerging wavefront, thus significantly enhancing the resolution of the tightly-focused optical wave. The formation of a light tongue with dimensions approaching those of the concave opening is here evidenced. This scheme is expected to have potential applications in optical trapping and detection.

  9. An acoustical analysis of a room with a concave dome ceiling element

    NASA Astrophysics Data System (ADS)

    Utami, Sentagi S.

    2004-05-01

    Concave surfaces are often considered detrimental in room acoustics, especially because of the impact they have on the distribution of sound energy. This paper explores certain acoustical characteristics and anomalies found in spaces below concave dome ceiling elements. The architectural design of the Darusshollah mosque in East Java, Indonesia is used as a case study with specific spatial and functional concerns. Investigations of the mosque have been conducted through both a 1:12 scale model and a computer model that utilizes ray tracing and image source methods. Analysis techniques are discussed. Results are presented and compared to provide useful insights into the acoustics of such distinctive environments.

  10. Fabrication of concave microlens arrays by local fictive temperature modification of fused silica.

    PubMed

    Zhang, Chuanchao; Liao, Wei; Yang, Ke; Liu, Taixiang; Bai, Yang; Zhang, Lijuan; Jiang, Xiaolong; Chen, Jing; Jiang, Yilan; Wang, Haijun; Luan, Xiaoyu; Zhou, Hai; Yuan, Xiaodong; Zheng, Wanguo

    2017-03-15

    A simple and convenient means of fabricating concave microlens arrays direct on silica glass by using the local fictive temperature modification of fused silica is presented. This method is based on the fact that an increased fictive temperature results in a much higher HF acid etching rate of fused silica. Combining the abrupt local fictive temperature enhancement by the CO2 laser pulse and the subsequent etching by the HF acid solution, concave microlens arrays with high fill factors, excellent smoothness, and optical performance are generated on fused silica.

  11. Baum's Algorithm Learns Intersections of Halfspaces with Respect to Log-Concave Distributions

    NASA Astrophysics Data System (ADS)

    Klivans, Adam R.; Long, Philip M.; Tang, Alex K.

    In 1990, E. Baum gave an elegant polynomial-time algorithm for learning the intersection of two origin-centered halfspaces with respect to any symmetric distribution (i.e., any {\\cal D} such that {\\cal D}(E) = {\\cal D}(-E)) [3]. Here we prove that his algorithm also succeeds with respect to any mean zero distribution with a log-concave density (a broad class of distributions that need not be symmetric). As far as we are aware, prior to this work, it was not known how to efficiently learn any class of intersections of halfspaces with respect to log-concave distributions.

  12. Nanoscale aluminum concaves for light-trapping in organic thin-films

    NASA Astrophysics Data System (ADS)

    Goszczak, Arkadiusz Jarosław; Adam, Jost; Cielecki, Paweł Piotr; Fiutowski, Jacek; Rubahn, Horst-Günter; Madsen, Morten

    2016-07-01

    Anodic aluminum oxide (AAO) templates, fabricated from oxalic acid and phosphoric acid, lead to non-periodic nanoscale concave structures in their underlying aluminum layer, which are investigated for their field-enhancement properties by applying a thin-film polymer coating based laser ablation technique. Local ablation spots, corresponding to field enhancement on the ridge edges of the aluminum concave nanostructures, are observed in surface-covering polymer films, and confirmed with FDTD studies. The field enhancement leads to improved light absorption in the applied polymer layers, which may be used as an efficient method for enhancing the power conversion efficiency of organic solar cells.

  13. Indirect methods to measure wetting and contact angles on spherical convex and concave surfaces.

    PubMed

    Extrand, C W; Moon, Sung In

    2012-05-22

    In this work, a method was developed for indirectly estimating contact angles of sessile liquid drops on convex and concave surfaces. Assuming that drops were sufficiently small that no gravitational distortion occurred, equations were derived to compute intrinsic contact angles from the radius of curvature of the solid surface, the volume of the liquid drop, and its contact diameter. These expressions were tested against experimental data for various liquids on polytetrafluoroethylene (PTFE) and polycarbonate (PC) in the form of flat surfaces, spheres, and concave cavities. Intrinsic contact angles estimated indirectly using dimensions and volumes generally agreed with the values measured directly from flat surfaces using the traditional tangent method.

  14. Static Thrust of an Annular Nozzle with a Concave Central Base

    NASA Technical Reports Server (NTRS)

    Corson, Blake W., Jr.; Mercer, Charles E.

    1960-01-01

    A static test of an annular nozzle with a concave central base, producing a jet in which tangents to the jet streamlines at the exit converged toward a region on the axis of symmetry downstream of the exit, has indicated good thrust performance. A value of nozzle-flow coefficient only slightly less than unity indicates the internal loss to be small. Pressures on the concave central base are relatively large and positive, and a predictable portion of the total thrust of the jet is exerted on the central base.

  15. Maximum likelihood estimation of the mixture of log-concave densities.

    PubMed

    Hu, Hao; Wu, Yichao; Yao, Weixin

    2016-09-01

    Finite mixture models are useful tools and can be estimated via the EM algorithm. A main drawback is the strong parametric assumption about the component densities. In this paper, a much more flexible mixture model is considered, which assumes each component density to be log-concave. Under fairly general conditions, the log-concave maximum likelihood estimator (LCMLE) exists and is consistent. Numeric examples are also made to demonstrate that the LCMLE improves the clustering results while comparing with the traditional MLE for parametric mixture models.

  16. Negative Goos-Hänchen shift on a concave dielectric interface.

    PubMed

    Zhou, L-M; Zou, C-L; Han, Z-F; Guo, G-C; Sun, F-W

    2011-03-01

    We study the Goos-Hänchen shift (GHS) on a curved surface through numerical simulation by the boundary element method. A negative GHS is first discovered on a concave dielectric interface below the critical angle, accompanied by a large positive GHS on the convexity. The simulation shows that the GHS on a planar interface is the composition of the GHS from a concave and the corresponding convex interface. This work will enrich the study of the GHS for different curved surfaces, which will have potential applications in micro-optics and near-field optics.

  17. Meniscus induced self organization of multiple deep concave wells in a microchannel for embryoid bodies generation.

    PubMed

    Jeong, Gi Seok; Jun, Yesl; Song, Ji Hoon; Shin, Soo Hyun; Lee, Sang-Hoon

    2012-01-07

    Embryonic stem cells (ESCs) have attracted great interest in the fields of tissue engineering, regenerative medicine, and organogenesis for their pluripotency and ability to self-renew. ESC aggregation, which produces an embryoid body (EB), has been widely utilized as a trigger of in vitro directed differentiation. In this paper, we propose a novel method for constructing large numbers of deep concave wells in PDMS microfluidic chips using the meniscus induced by the surface tension of a liquid PDMS prepolymer, and applied this chip for the mass production of uniform sized EBs. To investigate if the microenvironment in the deep concave well is suitable for ES cells, the oxygen diffusion to the deep concave well was analyzed by CFD simulation. Murine EBs were successfully formed in the deep concave wells without loss of cells and laborious careful intervention to refresh culture media. The size of the EBs was uniform, and retrieving of EBs was done just by flipping over the chip. All the processes including EB formation and harvest are easy and safe to cells, and their viability after completion of all processes was over 95%. The basic properties of the EBs were generated and their capacity to differentiate into 3 germ layers was investigated by analyzing the gene expression profile. The harvested EBs were found to differentiate into cardiac cells and neurons, and neurofilaments formed branches of elongated extensions more than 1.0 mm in length.

  18. Influence of patterned concave depth and surface curvature on anodization of titania nanotubes and alumina nanopores.

    PubMed

    Chen, Bo; Lu, Kathy

    2011-10-04

    Vertically aligned TiO(2) nanotube and Al(2)O(3) nanopore arrays have been obtained by pattern guided anodization with uniform concave depths. There are some studies about the effect of surface curvature on the growth of Al(2)O(3) nanopores. However, the surface curvature influence on the development of TiO(2) nanotubes is seldom studied. Moreover, there is no research about the effect of heterogeneous concave depths of the guiding patterns on the anodized TiO(2) nanotube and Al(2)O(3) nanopore characteristics, such as diameter, growth direction, and termination/bifurcation. In this study, focused ion beam lithography is used to create concave patterns with heterogeneous depths on flat surfaces and with uniform depths on curved surfaces. For the former, bending and bifurcation of nanotubes/nanopores are observed after the anodization. For the latter, bifurcation of a large tube into two smaller tubes occurs on concave surfaces, while termination of existing tubes occurs on convex surfaces. The growth direction of all TiO(2) nanotubes is perpendicular to the local surface and thus is different on different facets of the same Ti foil. At the edge of the Ti foil where two facets meet, the nanotube growth direction is bent, resulting in a large stress release that causes the formation of cracks.

  19. Blood vessels are concentrated within the implant surface concavities: a histologic study in rabbit tibia.

    PubMed

    Scarano, Antonio; Perrotti, Vittoria; Artese, Luciano; Degidi, Marco; Degidi, Davide; Piattelli, Adriano; Iezzi, Giovanna

    2014-07-01

    Angiogenesis plays a key role in bone formation and maintenance. Bone formation has been reported to initiate in the concavities rather than the convexities in a hydroxyapatite substratum and the implant threads of dental implants. The aim of the present study was to evaluate the number of the blood vessels inside the concavities and around the convexities of the threads of implants in a rabbit tibia model. A total of 32 thread-shaped implants blasted with apatitic calcium phosphate (TCP/HA blend) (Resorbable Blast Texturing, RBT) (Maestro, BioHorizons(®), Birmingham, AL, USA) were inserted in 8 rabbits. Each rabbit received 4 implants, 2 in the right and 2 in left tibia. Implants were retrieved after 1, 2, 4, and 8 weeks and treated to obtain thin ground sections. Statistically significant differences were found in the number of vessels that had formed in the concavities rather than the convexities of the implants after 1 (p = 0.000), and 2 weeks (p = 0.000), whilst no significant differences after 4 (p = 0.546) and 8 weeks (p = 0.275) were detected. The present results supported the hypothesis that blood vessel formation was stimulated by the presence of the concavities, which may provide a suitable environment in which mechanical forces, concentrations and gradients of chemotactic molecules and blood clot retention may all drive vascular and bone cell migration.

  20. Bicuspid aortic valve hemodynamics does not promote remodeling in porcine aortic wall concavity

    PubMed Central

    Atkins, Samantha K; Moore, Alison N; Sucosky, Philippe

    2016-01-01

    AIM: To investigate the role of type-I left-right bicuspid aortic valve (LR-BAV) hemodynamic stresses in the remodeling of the thoracic ascending aorta (AA) concavity, in the absence of underlying genetic or structural defects. METHODS: Transient wall shear stress (WSS) profiles in the concavity of tricuspid aortic valve (TAV) and LR-BAV AAs were obtained computationally. Tissue specimens excised from the concavity of normal (non-dilated) porcine AAs were subjected for 48 h to those stress environments using a shear stress bioreactor. Tissue remodeling was characterized in terms of matrix metalloproteinase (MMP) expression and activity via immunostaining and gelatin zymography. RESULTS: Immunostaining semi-quantification results indicated no significant difference in MMP-2 and MMP-9 expression between the tissue groups exposed to TAV and LR-BAV AA WSS (P = 0.80 and P = 0.19, respectively). Zymography densitometry revealed no difference in MMP-2 activity (total activity, active form and latent form) between the groups subjected to TAV AA and LR-BAV AA WSS (P = 0.08, P = 0.15 and P = 0.59, respectively). CONCLUSION: The hemodynamic stress environment present in the concavity of type-I LR-BAV AA does not cause any significant change in proteolytic enzyme expression and activity as compared to that present in the TAV AA. PMID:26839660

  1. The Scallop's Eye--A Concave Mirror in the Context of Biology

    ERIC Educational Resources Information Center

    Colicchia, Giuseppe; Waltner, Christine; Hopf, Martin; Wiesner, Hartmut

    2009-01-01

    Teaching physics in the context of medicine or biology is a way to generate students' interest in physics. A more uncommon type of eye, the scallop's eye (an eye with a spherical concave mirror, which is similar to a Newtonian or Schmidt telescope) and the image-forming mechanism in this eye are described. Also, a simple eye model, which can…

  2. [Design of flat field holographic concave grating for near-infrared spectrophotometer].

    PubMed

    Xiang, Xian-Yi; Wen, Zhi-Yu

    2008-07-01

    Near-infrared spectrum analysis can be used to determine the nature or test quantitatively some chemical compositions by detecting molecular double frequency and multiple frequency absorption. It has been used in agriculture, biology, petrifaction, foodstuff, medicament, spinning and other fields. Near-infrared spectrophotometer is the main apparatus for near-infrared spectrum analysis, and the grating is the most important part of the apparatus. Based on holographic concave grating theory and optic design software CODE V, a flat field holographic concave grating for near-infrared spectrophotometer was designed from primary structure, which relied on global optimization of the software. The contradiction between wide spectrum bound and limited spectrum extension was resolved, aberrations were reduced successfully, spectrum information was utilized fully, and the optic structure of spectrometer was highly efficient. Using CODE V software, complex high-order aberration equations need not be solved, the result can be evaluated quickly, flat field and resolving power can be kept in balance, and the work efficiency is also enhanced. A paradigm of flat field holographic concave grating is given, it works between 900 nm to 1 700 nm, the diameter of the concave grating is 25 mm, and F/ # is 1. 5. The design result was analyzed and evaluated. It was showed that if the slit source, whose width is 50 microm, is used to reconstruction, the theoretic resolution capacity is better than 6.3 nm.

  3. The Scallop's Eye--A Concave Mirror in the Context of Biology

    ERIC Educational Resources Information Center

    Colicchia, Giuseppe; Waltner, Christine; Hopf, Martin; Wiesner, Hartmut

    2009-01-01

    Teaching physics in the context of medicine or biology is a way to generate students' interest in physics. A more uncommon type of eye, the scallop's eye (an eye with a spherical concave mirror, which is similar to a Newtonian or Schmidt telescope) and the image-forming mechanism in this eye are described. Also, a simple eye model, which can…

  4. Effect of concave rectangular winglet vortex generator on convection coefficient of heat transfer

    NASA Astrophysics Data System (ADS)

    Syaiful, Sugiri, Gladys; Soetanto, Maria F.; Bae, Myung-whan

    2017-01-01

    This study shows an experimental result of effects of concave rectangular winglet vortex generator on convection heat transfer coefficient. There are two types of vortex generator those are rectangular winglet and concave rectangular winglet. The aim of this study is to observe effects of geometry and numbers of vortex generator to the increase of heat transfer coefficient. This experiment was done in a glass rectangular channel. Overall, this experiment was conducted with (rectangular and concave rectangular winglets) and without (baseline) vortex generator. Both types of vortex generator were placed at a 30° angle of attack, in an inline position, and variation numbers of vortex generator row of 1, 2 and 3 rows. Vortex generators were mounted on an aluminum plate which was mounted on a heater with 35 watts of heat, inside the rectangular channel. Airflow passed through vortex generators was varied by its inlet velocity to be 0.4 m/s to 2.0 m/s with an interval of 0.2 m/s. The experimental result shows that 3 row of concave rectangular winglet gives the highest heat transfer coefficient enhancement. Nusselt number and j-factor increase but thermal resistance decrease. Experiment results that Nusselt number and j-factor increase up to 205% while thermal resistance decreases up to 67% compared to baseline for the highest Reynolds number.

  5. Stable anisotropic plasma confinement in magnetic configurations with convex-concave field lines

    NASA Astrophysics Data System (ADS)

    Tsventoukh, M. M.

    2014-02-01

    It is shown that a combination of the convex and the concave part of a field line provides a strong stabilizing action against convective (flute-interchange) plasma instability (Tsventoukh 2011 Nucl. Fusion 51 112002). This results in internal peaking of the stable plasma pressure profile that is calculated from the collisionless kinetic stability criterion for any magnetic confinement system with combination of mirrors and cusps. Connection of the convex and concave field line parts results in a reduction of the space charge that drives the unstable E × B motion, as there is an opposite direction of the particle drift in a non-uniform field at convex and concave field lines. The pressure peaking arises at the minimum of the second adiabatic invariant J that takes place at the ‘middle’ of a tandem mirror-cusp transverse cross-section. The position of the minimum in J varies with the particle pitch angle that results in a shift of the peaking position depending on plasma anisotropy. This allows one to improve a stable peaked pressure profile at a convex-concave field by changing the plasma anisotropy over the trap cross-section. Examples of such anisotropic distribution functions are found that give an additional substantial enhancement in the maximal central pressure. Furthermore, the shape of new calculated stable profiles has a wide central plasma layer instead of a narrow peak.

  6. A method to search for large-scale concavities in asteroid shape models

    NASA Astrophysics Data System (ADS)

    Devogèle, M.; Rivet, J. P.; Tanga, P.; Bendjoya, Ph.; Surdej, J.; Bartczak, P.; Hanus, J.

    2015-11-01

    Photometric light-curve inversion of minor planets has proven to produce a unique model solution only under the hypothesis that the asteroid is convex. However, it was suggested that the resulting shape model, for the case of non-convex asteroids, is the convex-hull of the true asteroid non-convex shape. While a convex shape is already useful to provide the overall aspect of the target, much information about real shapes is missed, as we know that asteroids are very irregular. It is a commonly accepted evidence that large flat areas sometimes appearing on shapes derived from light curves correspond to concave areas, but this information has not been further explored and exploited so far. We present in this paper a method that allows to predict the presence of concavities from such flat regions. This method analyses the distribution of the local normals to the facets composing shape models to predict the presence of abnormally large flat surfaces. In order to test our approach, we consider here its application to a large family of synthetic asteroid shapes, and to real asteroids with large-scale concavities, whose detailed shape is known by other kinds of observations (radar and spacecraft encounters). The method that we propose has proven to be reliable and capable of providing a qualitative indication of the relevance of concavities on well-constrained asteroid shapes derived from purely photometric data sets.

  7. Slow approach to steady motion of a concave body in a free-molecular gas.

    PubMed

    Tsuji, Tetsuro; Arai, Junichi; Kawano, Satoyuki

    2015-07-01

    A body in a free-molecular gas accelerated by a constant external force is considered on the basis of kinetic theory. The body is an infinitely long rectangular hollow column with one face removed, and thus it has a squarish U-shaped cross section. The concave part of the body points toward the direction of motion, and thus the gas molecules may be trapped in the concavity. Gas molecules undergo diffuse reflection on a base part, whereas specular reflection on two lateral parts. It is numerically shown that the velocity of the body approaches a terminal velocity, for which a drag force exerted by the gas counterbalances the external force, in such a way that their difference decreases in proportion to the inverse square of time for a large time. This rate of approach is slower than the known rate proportional to the inverse cube of time in the case of a body without concavity [Aoki et al., Phys. Rev. E 80, 016309 (2009)]. Based on the detailed investigation on the velocity distribution function of gas molecules impinging on the body, it is clarified that the concavity prevents some molecules from escaping to infinity. This trapping enhances the effect of recollision between the body and the gas molecules, which is the cause of the inverse power laws, and thus leads to the slower approach.

  8. On some fractional equations with convex-concave and logistic-type nonlinearities

    NASA Astrophysics Data System (ADS)

    Carboni, Giulia; Mugnai, Dimitri

    2017-02-01

    We consider existence and multiplicity results for a semilinear problem driven by the square root of the negative Laplacian in presence of a nonlinear term which is the difference of two powers. In the case of convex-concave powers, a precise description of the problem at the threshold value of a given parameter is established through variational methods and truncation techniques.

  9. Fabrication and test of a concave oblate ellipsoid with large relative aperture

    NASA Astrophysics Data System (ADS)

    Li, Ke-xin; Yuan, Li-yin; Hao, Pei-ming

    2010-10-01

    Fabrication and test of the concave oblate ellipsoid becomes more difficult as the mirror relative aperture gets larger. The concave oblate ellipsoid discussed in this paper, has a very large relative aperture. Two processing methods are introduced. One is drilling sub-mirror from the mother mirror, the other is processing sub-mirror merely. A novel method to calculate aspheric grinding amount of the latter method is proposed. As the clear aperture and aperture decenter of the concave oblate ellipsoid in this paper are not large, the former processing method is finally adopted. Two online processing testing methods are proposed. One is reflective auto-collimating test; the other is refractive auto-collimating test. As for the former, a negative power lens is applied to compensate the positive spherical aberration of the concave oblate ellipsoid. The compensator has a negative - negative - positive configuration. As for the latter, the back surface of the spherical is designed to be an auxiliary spherical one. Its compensator is negative- positive- positive compensator. Besides, a high-precision plane is used to realize auto-collimating test. And the form test is selected for its online processing testing. By optical design of the compensator and gradual aberration optimization of its alignment, the test accuracy of the oblate ellipsoid shape can be achieved 1/10λ (632.8nm).

  10. Energetic protons from an ultraintense laser interacting with a symmetric parabolic concave target

    SciTech Connect

    Ali Bake, Muhammad; Xie Baisong; Shan Zhang; Wang Hongyu

    2013-03-15

    A scheme of a symmetric parabolic concave target irradiated by an ultraintense laser for efficient proton acceleration is proposed and involved problem is studied by using two-dimensional particle-in-cell (PIC) simulations. Results indicate that on one hand, the laser field is focused by the front parabolic concave surface of target and, on the other hand, more energetic hot electrons will traverse to the rear surface of target due to concave shape. The space-charge-separation field, induced by those hot electrons escaping form parabolic concave rear surface of target, can accelerate protons to relatively high energy with narrow energy spread. The dependence of the efficiency of proton acceleration on the target parameters is examined, and the optimal target parameters are obtained. Particle-in-cell simulations show that the proton peak energy and energy spread are greatly enhanced when the target parameters are chosen optimal, for example, a proton bunch with the maximum energy {approx}27.5 MeV and energy spread {approx}7% can be generated. Some implications of our results to experiments and comparisons with the other works are also discussed briefly.

  11. A Basic Experimental Study for Imaging by Monopolar Pulse Radiated from Concave Polyvinylidene Fluoride (PVDF) Transducer

    NASA Astrophysics Data System (ADS)

    Ooyashiki, Atsuko; Yoshida, Yasuo; Inoue, Hiroshi; Murata, Kenji

    2004-05-01

    Monopolar C-mode imaging using a concaved polyvinylidene fluoride (PVDF) transducer was developed. The basic characteristics of the spreading of the ultrasound field are measured and discussed with respect to the imaging, along with the spatial resolution, and the C-mode image of a printed circuit board (PCB) surface.

  12. Exceptional methanol electro-oxidation activity by bimetallic concave and dendritic Pt-Cu nanocrystals catalysts

    NASA Astrophysics Data System (ADS)

    Wang, Ying-Xia; Zhou, Hui-Jing; Sun, Ping-Chuan; Chen, Tie-Hong

    2014-01-01

    PtCux (x = 1, 2 and 3) bimetallic nanocrystals with concave surface and dendritic morphology were prepared and used as electrocatalysts in methanol oxidation reaction (MOR) for polymer electrolyte membrane fuel cells. The bimetallic nanocrystals were synthesized via one-pot co-reduction of H2PtCl6 and Cu(acac)2 by oleylamine and polyvinyl pyrrolidone (PVP) in an autoclave at 180 °C. The concave dendritic bimetallic nanostructure consisted of a core rich in Cu and nanodendrites rich in Pt, which was formed via galvanic replacement of Cu by Pt. It was found that PVP played an important role in initiating, facilitating, and directing the replacement reaction. The electrochemical properties of the PtCux were characterized by cyclic voltammetry (CV) and chronoamperometry (CA). The concave dendritic PtCu2/C nanocrystals exhibited exceptionally high activity and strong poisoning resistance in MOR. At 0.75 V (vs. reversible hydrogen electrode, RHE) the mass activity and specific activity of PtCu2/C were 3.3 and 4.1 times higher than those of the commercial Pt/C catalysts, respectively. The enhanced catalytic activity could be attributed to the unique concave dendritic morphology of the bimetallic nanocrystals.

  13. Convex Instrumented Hemiepiphysiodesis With Concave Distraction: A Treatment Option for Long Sweeping Congenital Curves.

    PubMed

    Demirkiran, Gokhan; Dede, Ozgur; Ayvaz, Mehmet; Bas, Can E; Alanay, Ahmet; Yazici, Muharrem

    2016-01-01

    Convex hemiepiphysiodesis has been reported to have mixed results in the treatment of congenital spine deformities. Multiple modifications of the original technique were suggested to improve the results. The purpose of this study is to report the results and complications of an instrumented convex growth arrest procedure modified with concave distraction. The records of 11 patients with long sweeping congenital curves (involving multiple anomalous vertebrae) who underwent convex instrumented hemiepiphysiodesis with concave distraction were evaluated. Mean age at index operation was 58 months (range, 29 to 101 mo). Lengthening of the concave distraction rod was done every 6 months. The magnitude of coronal/sagittal deformity and T1-T12 height were measured on the preoperative, postoperative, and latest follow-up radiographs. Average follow-up was 44.9 months (range, 24 to 89 mo). In the coronal plane, the convex hemiepiphysiodesis segment was corrected from an average of 60.5 to 40.4 degrees postoperatively and further improved to 35.5 degrees at the latest follow-up. The distracted segment was corrected from 33.4 to 15.2 degrees postoperatively and to 12.7 degrees at the latest follow-up. Sagittal plane alignment was minimally affected. The average T1-T12 height was 157.1 mm in the early postoperative period and 181.1 mm at last follow-up. During follow-up, we identified partial pull-out of screws on the distraction side in 5 of the 11 patients and rod breakages in 3 patients. These were revised during planned lengthenings. There were no unplanned surgeries, deep wound infections, nor neurological complications. Convex instrumented hemiepiphysiodesis with concave distraction resulted in good curve correction while maintaining the growth of thorax. The correction of the anomalous segment improved over time, proving the effectiveness of the hemiepiphysiodesis. Addition of a concave distraction construct appears to enhance spinal growth, thereby augmenting the

  14. Navier-Stokes Computations With One-Equation Turbulence Model for Flows Along Concave Wall Surfaces

    NASA Technical Reports Server (NTRS)

    Wang, Chi R.

    2005-01-01

    This report presents the use of a time-marching three-dimensional compressible Navier-Stokes equation numerical solver with a one-equation turbulence model to simulate the flow fields developed along concave wall surfaces without and with a downstream extension flat wall surface. The 3-D Navier- Stokes numerical solver came from the NASA Glenn-HT code. The one-equation turbulence model was derived from the Spalart and Allmaras model. The computational approach was first calibrated with the computations of the velocity and Reynolds shear stress profiles of a steady flat plate boundary layer flow. The computational approach was then used to simulate developing boundary layer flows along concave wall surfaces without and with a downstream extension wall. The author investigated the computational results of surface friction factors, near surface velocity components, near wall temperatures, and a turbulent shear stress component in terms of turbulence modeling, computational mesh configurations, inlet turbulence level, and time iteration step. The computational results were compared with existing measurements of skin friction factors, velocity components, and shear stresses of the developing boundary layer flows. With a fine computational mesh and a one-equation model, the computational approach could predict accurately the skin friction factors, near surface velocity and temperature, and shear stress within the flows. The computed velocity components and shear stresses also showed the vortices effect on the velocity variations over a concave wall. The computed eddy viscosities at the near wall locations were also compared with the results from a two equation turbulence modeling technique. The inlet turbulence length scale was found to have little effect on the eddy viscosities at locations near the concave wall surface. The eddy viscosities, from the one-equation and two-equation modeling, were comparable at most stream-wise stations. The present one

  15. Elevated Channel Concavities Arising from Sediment-Flux Effects in Natural Rivers

    NASA Astrophysics Data System (ADS)

    Hobley, D. E. J.; Sinclair, H. D.; Gasparini, N. M.; Tucker, G. E.; Cowie, P. A.; Adams, J. M.; Hutton, E. W. H.; Istanbulluoglu, E.; Nudurupati, S. S.

    2014-12-01

    The concavity of an incising river system - a measure of the rate of change of its bed slope with increasing discharge downstream - is a commonly used metric in fluvial geomorphology. It is commonly used in assessing variation of factors such as uplift, climate, and rock type along a system in a qualitative way, and underpins a number of quantitative analyses in tectonic geomorphology, such as the normalized channel steepness index. However, the factors that fundamentally control channel concavities in rocky streams remain relatively poorly understood, especially in rivers that are undergoing transient response to a perturbation in their boundary conditions.Here we use a combination of field data and numerical modeling to demonstrate that elevated channel concavities are a common and shared response to the propagation of a convex-upward "knickzone" through a bedrock channel long profile. Simulations using the novel modeling framework Landlab exploring thresholded incision and saltation-abrasion theory indicate that the presence of the knickzone can perturb the relative sediment flux in the area immediately downstream of the convexity, allowing enhanced erosion there and systematic elevation of channel concavities in reaches downstream of this point. The reality of this effect is demonstrated using field and remotely sensed data from three sites - the Red River area, Yunnan, China; channels on the Ladakh batholith, Indian Himalaya; and the Fagaras Alps, Romania. All contain broad scale migrating knickzones, but the causes of the disturbances that produced them and scales of the systems differ. Nonetheless, the concavities of all the channels are all elevated in the same way downstream of knickzones, consistent with the modeling output. These results demonstrate the ubiquity of sediment flux effects on erosion rates in many natural channels, and have consequences for the way we read tectonic histories from landscapes.

  16. Rapid prototyping of concave microwells for the formation of 3D multicellular cancer aggregates for drug screening

    PubMed Central

    Tu, Ting-Yuan; Wang, Zhe; Bai, Jing; Sun, Wei; Peng, Weng Kung; Huang, Ruby Yun-Ju; Thiery, Jean-Paul; Kamm, Roger D.

    2014-01-01

    Microwell technology has revolutionized many aspects of in vitro cellular studies from 2-dimensional (2D) traditional cultures to 3-dimensional (3D) in vivo-like functional assays. However, existing lithography-based approaches are often costly and time-consuming. This study presents a rapid, low-cost prototyping method of CO2 laser ablation of a conventional untreated culture dish to create concave microwells used for generating multicellular aggregates, which can be readily available for general laboratories. Polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), and polystyrene (PS) microwells were investigated, and each produced distinctive microwell features. Among these three materials, PS cell culture dishes produced the optimal surface smoothness and roundness. A549 lung cancer cells were grown to form cancer aggregates of controllable size from ~40 to ~80 μm in PS microwells. Functional assays of spheroids were performed to study migration on 2D substrates and in 3D hydrogel conditions as a step towards recapitulating the dissemination of cancer cells. Preclinical anti-cancer drug screening was investigated and revealed considerable differences between 2D and 3D conditions, indicating the importance of assay type as well as the utility of the present approach. PMID:23983140

  17. Analysis and design of concave grating-based devices for multi-wavelength optical networks

    NASA Astrophysics Data System (ADS)

    Churin, Evgeny G.

    This thesis is focused on the analysis and design of concave holographic gratings for applications in wavelength division multiplexed (WDM) optical network devices, such as multi/demultiplexers, routers and channel equalizers. The main advantage of this approach is that a single optical element can perform both functions of dispersion and imaging. However, the design of such gratings for operation in optical fibre communication networks requires the understanding and control of dominant optical aberrations, stray light, and polarization sensitivity. The solution of these problems forms the basis of the work in this thesis. Chapter 1 presents the motivation for the work, describes the major objectives and lists the main original contributions. Chapter 2 reviews related works in the field of WDM optical networks. Different published methods and techniques used for channel separation are described. Chapter 3 describes the analysis of crosstalk in free-space WDM demultiplexers and wavelength routers due to aberrations, diffraction at the aperture, and diffuse scattering from non-uniformities. It is demonstrated experimentally that holographic grating can give background crosstalk as low as -60 dB. Holographic grating-based wavelength routers are shown to be absolutely scalable from the coherent crosstalk point of view, allowing a large number of subscribers/nodes to be interconnected. Chapter 4 presents aberration analysis of concave grating. New general analytic formulae that define the parameters of concave grating mounts providing stationary and superstationary astigmatism are derived. These mounts offer diffraction-limited imaging within operating spectral range of WDM demultiplexers. A novel retro-reflective scheme of demultiplexer with concave grating and convex mirror resulting in double dispersion and large image field is proposed and analyzed. Chapter 5 describes in detail all stages of design and adjustment of an athermal 49-channel demultiplexer. The method

  18. Anterior Shoulder Instability Is Associated With an Underlying Deficiency of the Bony Glenoid Concavity.

    PubMed

    Moroder, Philipp; Ernstbrunner, Lukas; Pomwenger, Werner; Oberhauser, Florian; Hitzl, Wolfgang; Tauber, Mark; Resch, Herbert; Moroder, Rudi

    2015-07-01

    To determine whether anterior shoulder instability is associated with an inherent deficiency of the bony glenoid concavity, which results in a reduced bony shoulder stability ratio (BSSR). In this case-control study, we searched the institutional database for patients treated for unilateral recurrent anterior shoulder instability. We included 30 consecutive patients with atraumatic instability, 30 consecutive patients with traumatic instability, and 36 matched healthy controls, for a total of 96 shoulders. Computed tomography images of the unaffected shoulders of the instability patients were compared with images of the ipsilateral shoulders of age- and sex-matched healthy controls for differences in glenoid morphology. By use of a mathematical formula based on Pythagorean trigonometric identities, the mean BSSRs of the different groups were calculated and compared. Validation of the formula was accomplished by finite element analysis. The mean BSSR of atraumatic instability patients was 17.9% ± 8.5% and therefore significantly lower than the mean BSSR of 31.1% ± 7.5% of the control group (13.2%; 95% confidence interval [CI], 9.1% to 17.4%; P < .001). The mean BSSR of the traumatic instability group was higher, at 23.9% ± 8.5% (P = .007), but still showed a deficit of 7.2% (95% CI, 2.8% to 11.7%; P = .002) compared with controls. The atraumatic instability group showed a mean reduction of 0.9 mm (95% CI, 0.6 to 1.1 mm; P < .001) in concavity depth and a decrease of 2.9° (95% CI, 0.4° to 5.3°; P = .021) in concavity retroversion, whereas the traumatic instability patients had a reduction of 0.4 mm (95% CI, 0.1 to 0.8 mm; P = .006) in concavity depth. Neither of the instability groups differed significantly from their respective controls in terms of glenoid concavity diameter, head radius, or glenoid vault morphology. Anterior shoulder instability is associated with an inherent flattening of the bony glenoid concavity, which significantly decreases the

  19. Understanding the formation of CuS concave superstructures with peroxidase-like activity

    NASA Astrophysics Data System (ADS)

    He, Weiwei; Jia, Huimin; Li, Xiaoxiao; Lei, Yan; Li, Jing; Zhao, Hongxiao; Mi, Liwei; Zhang, Lizhi; Zheng, Zhi

    2012-05-01

    Copper sulfide (CuS) concave polyhedral superstructures (CPSs) have been successfully prepared in an ethanolic solution by a simple solvothermal reaction without the use of surfactants or templates. Two typical well defined, high symmetry CuS concave polyhedrons, forming a concave truncated cuboctahedron and icosahedron were prepared. The effect of the reaction time, temperature and different Cu ion and sulfur sources on the formation of CuS CPSs were investigated and a possible formation mechanism was proposed and discussed based on gas chromatography-mass spectrometry. More importantly, we found, for the first time, that the CuS CPSs exhibit intrinsic peroxidase-like activity, as they can quickly catalyze the oxidation of typical horseradish peroxidase (HRP) substrates, 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD), in the presence of hydrogen peroxide. In addition to the recent discoveries regarding peroxidase mimetics on Fe3O4 NPs and carbon nanostructures, our findings suggest a new kind of candidate for peroxidase mimics. This may open up a new application field of CuS micro-nano structures in biodetection, biocatalysis and environmental monitoring.Copper sulfide (CuS) concave polyhedral superstructures (CPSs) have been successfully prepared in an ethanolic solution by a simple solvothermal reaction without the use of surfactants or templates. Two typical well defined, high symmetry CuS concave polyhedrons, forming a concave truncated cuboctahedron and icosahedron were prepared. The effect of the reaction time, temperature and different Cu ion and sulfur sources on the formation of CuS CPSs were investigated and a possible formation mechanism was proposed and discussed based on gas chromatography-mass spectrometry. More importantly, we found, for the first time, that the CuS CPSs exhibit intrinsic peroxidase-like activity, as they can quickly catalyze the oxidation of typical horseradish peroxidase (HRP) substrates, 3

  20. A study of the depth and size of concave cube Au nanoparticles as highly sensitive SERS probes

    NASA Astrophysics Data System (ADS)

    Romo-Herrera, J. M.; González, A. L.; Guerrini, L.; Castiello, F. R.; Alonso-Nuñez, G.; Contreras, O. E.; Alvarez-Puebla, R. A.

    2016-03-01

    High and uniform near fields are localized at the eight similar sharp corners of cubic gold nanoparticles. Moreover, by introducing concavity in the particle lateral planes, such field intensities can be further increased and tuned in the near infrared region without altering the overall size of the nanoparticles. Herein, we perform a thorough investigation of the morphological, crystallographic and plasmonic properties of concave gold nanocubes (GNCs) in the sub-70 nm size range, for their potential application as highly efficient SERS substrates in size-limiting cases. Theoretical calculations indicate that the highest increment of the near-field is located at the eight sharp tips and, interestingly, a medium near-field increment is also activated over the volume next to the concave surface. Remarkably, the plasmonic response of the concave cubic morphology showed great sensitivity to the concavity degree. Experimental SERS analysis nicely matches the outcome of the theoretical model, confirming that medium-sized concave GNCs (35 nm side length) possess the highest SERS activity upon excitation with a 633 nm laser, whereas larger 61 nm side concave GNCs dominate the optical response at 785 nm. Due to their size-intensity trade off, we envision that such small concave gold nanocubes can provide a highly active and efficient SERS platform for size-limiting applications, especially when near infrared excitations are required.High and uniform near fields are localized at the eight similar sharp corners of cubic gold nanoparticles. Moreover, by introducing concavity in the particle lateral planes, such field intensities can be further increased and tuned in the near infrared region without altering the overall size of the nanoparticles. Herein, we perform a thorough investigation of the morphological, crystallographic and plasmonic properties of concave gold nanocubes (GNCs) in the sub-70 nm size range, for their potential application as highly efficient SERS

  1. A combination of concave/convex surfaces for field-enhancement optimization: the indented nanocone.

    PubMed

    García-Etxarri, Aitzol; Apell, Peter; Käll, Mikael; Aizpurua, Javier

    2012-11-05

    We introduce a design strategy to maximize the Near Field (NF) enhancement near plasmonic antennas. We start by identifying and studying the basic electromagnetic effects that contribute to the electric near field enhancement. Next, we show how the concatenation of a convex and a concave surface allows merging all the effects on a single, continuous nanoantenna. As an example of this NF maximization strategy, we engineer a nanostructure, the indented nanocone. This structure, combines all the studied NF maximization effects with a synergistic boost provided by a Fano-like interference effect activated by the presence of the concave surface. As a result, the antenna exhibits a NF amplitude enhancement of ~ 800, which transforms into ~1600 when coupled to a perfect metallic surface. This strong enhancement makes the proposed structure a robust candidate to be used in field enhancement based technologies. Further elaborations of the concept may produce even larger and more effective enhancements.

  2. Properties of Plano-Concave Ultrasonic Resonator and Application to Velocity Dispersion Measurement

    NASA Astrophysics Data System (ADS)

    Bae, Jong-Rim; Choi, Pak-Kon; Takagi, Kenshiro

    1986-09-01

    The resonance characteristics of a plano-concave ultrasonic resonator, newly designed for precise measurements of ultrasonic velocity and absorption, were experimentally investigated over a frequency range between 100 kHz and 2MHz using five liquids with various absorption coefficients and acoustic impedances. The instrumental loss of the resonator was determined as a function of the frequency, which is subtracted from the observed resonance width in order to determine absorption in liquids. It was also found that water is the most suitable reference liquid for obtaining the instrumental loss curve of piano-concave resonator. To measure the velocity from the resonance interval, the frequency dependence of the apparent acoustic path length was observed and the results were theoretically described with a composite-resonator model consisting of an ultrasonic transducer, a sample liquid and a metal reflector. To demonstrate the usefulness of the new resonator, the velocity dispersion due to a relaxation effect was observed in methyl cyclohexane.

  3. Precursor salt assisted syntheses of high-index faceted concave hexagon and nanorod-like polyoxometalates

    NASA Astrophysics Data System (ADS)

    Pal, Jaya; Ganguly, Mainak; Mondal, Chanchal; Negishi, Yuichi; Pal, Tarasankar

    2014-12-01

    This paper describes an effective method for a precursor salt assisted fabrication and reshaping of two different polyoxometalates [(NH4)2Cu(MoO4)2 (ACM) and Cu3(MoO4)2(OH)2 (CMOH)] into five distinctive shapes through straightforward and indirect routes. Explicit regulation of the structural arrangements of ACM and CMOH has been studied in detail with altered precursor salt concentration employing our laboratory developed modified hydrothermal (MHT) method. Morphologically different ACM 3D architectures are evolved with higher molybdate concentration, whereas 1D growth of CMOH is observed with increased copper concentration. Interesting morphological transformation of the products has been accomplished employing one precursor salt at a time without using any other foreign reagent. It has been proven that large ACMs become labile in the presence of incoming Cu(ii) and NH4+ ions of the precursor salts. A new strategy for the conversion of faceted ACMs (hexagonal plate, circular plate and hollow flower) to exclusive CMOH nanorods through a Cu(ii) assisted reaction has been adopted. According to thermodynamic consideration, the synthesis of rare concave nanostructures with high index facet is still challenging due to their higher reactivity. In this study, concave hexagonal ACM with high index facet {hkl} has been successfully prepared for the first time from hexagonal ACM through simple etching with ammonium heptamolybdate (AHM), which is another precursor salt. Hexagonal ACM corrugates to a concave hexagon because of the higher reactivity of the {001} crystal plane than that of the {010} plane. It has been shown that high index facet exposed concave hexagonal ACM serves as a better catalyst for the photodegradation of dye than the other microstructures enclosed by low index facets.This paper describes an effective method for a precursor salt assisted fabrication and reshaping of two different polyoxometalates [(NH4)2Cu(MoO4)2 (ACM) and Cu3(MoO4)2(OH)2 (CMOH)] into

  4. Reproducible and recyclable SERS substrates: Flower-like Ag structures with concave surfaces formed by electrodeposition

    NASA Astrophysics Data System (ADS)

    Bian, Juncao; Shu, Shiwei; Li, Jianfu; Huang, Chao; Li, Yang Yang; Zhang, Rui-Qin

    2015-04-01

    Direct synthesis of three-dimensional Ag structures on solid substrates for the purposes of producing reproducible and recyclable surface-enhanced Raman scattering (SERS) applications remains challenging. In this work, flower-like Ag structures with concave surfaces (FACS) were successfully electrodeposited onto ITO glass using the double-potentiostatic method. The FACS, with an enhancement factor of the order of 108, exhibited a SERS signal intensity 3.3 times stronger than that measured from Ag nanostructures without concave surfaces. A cleaning procedure involving lengthy immersion of the sample in ethanol and KNO3 was proposed to recycle the substrate and confirmed by using rhodamine 6G, adenine, and 4-aminothiophenol as target molecules. The findings can help to advance the practical applications of Ag nanostructure-based SERS substrates.

  5. Improvement of the optical imaging technique for intact rat brain using a plano-concave lens.

    PubMed

    Kawai, Minako; Hama, Noriyuki; Ito, Shin-Ichi; Hirota, Akihiko

    2014-11-01

    Use of a plano-concave lens improved the quality of optical signals from the rat cerebral cortex by improving the focus. When detecting neural activity from a curved surface of an in vivo brain by optical techniques, it is not possible to adjust the focus equally over the entire detecting area in the two-dimensional plane, since the active window of the optical detector is usually flat, while the intact brain surface is spherical. It has been known that the size of the optical signal is reduced as the distance of the real image to the active window of the detector increases; therefore, the level of the signal-to-noise ratio obtained from the unfocused area often becomes insufficient for quantitative physiological analyses. By placing a plano-concave lens on the cerebral cortex, we succeeded in obtaining a two-dimensional image that has no unfocused area over an entire image recorded by the detector.

  6. The contact angle for a droplet on homogeneous and spherical concave surfaces

    NASA Astrophysics Data System (ADS)

    Hu, Ai-Jun; Lv, Bao-Zhan; Wang, Xiao-Song; Zhou, Long

    2016-03-01

    Wetting of droplets on homogeneous and spherical concave rough surfaces is investigated based on thermodynamics. In this study, neglecting the droplet gravity and the thickness of the precursor film of the liquid-vapor interface, the three-phase system is divided into six parts using Gibbs concept of dividing surface. The system Helmholtz free energy is established based on thermodynamics. Supposing the temperature and chemical potential to be constant, a new generalized Young’s equation of the equilibrium contact angle for a spherical droplet on a spherical concave rough surfaces is obtained including the line tension effects. Under certain conditions, this generalized Young’s equation is the same as the Rusanov’s equation.

  7. Heat transfer and flow characteristics of jets impinging on a concave hemispherical plate

    NASA Technical Reports Server (NTRS)

    Hrycak, P.

    1982-01-01

    The present study is concerned with an experimental investigation of the flow characteristics and heat transfer from turbulent air jets impinging normally on a concave hemispherical plate (CHP). It is found that the incompressible, turbulent jets impinging on a CHP are in many respects similar to the jets impinging on a flat plate. The observed differences are due to effects of curvature and to a slightly higher turbulence level inside of the CHP. Attention is given to the experimental apparatus, aspects of inner boundary layer development, the maximum velocity decay in a wall jet, the derivation of a maximum velocity decay formula, the influence of curvature on stagnation point heat transfer, and heat transfer calculations for a concave hemispherical plate.

  8. Experimental study of the laminar-turbulent transition of a concave wall in a parallel flow

    NASA Technical Reports Server (NTRS)

    Bippes, H.

    1978-01-01

    The instability of the laminar boundary layer flow along a concave wall was studied. Observations of these three-dimensional boundary layer phenomena were made using the hydrogen-bubble visualization technique. With the application of stereo-photogrammetric methods in the air-water system it was possible to investigate the flow processes qualitatively and quantitatively. In the case of a concave wall of sufficient curvature, a primary instability occurs first in the form of Goertler vortices with wave lengths depending upon the boundary layer thickness and the wall curvature. At the onset the amplification rate is in agreement with the linear theory. Later, during the non-linear amplification stage, periodic spanwise vorticity concentrations develop in the low velocity region between the longitudinal vortices. Then a meandering motion of the longitudinal vortex streets subsequently ensues, leading to turbulence.

  9. A METHOD OF TREATING UNSTRUCTURED CONCAVE CELLS IN STAGGERED-GRID LAGRANGIAN HYDRODYNAMICS

    SciTech Connect

    C. ROUSCULP; D. BURTON

    2000-12-01

    A method is proposed for the treatment of concave cells in staggered-grid Lagrangian hydrodynamics. The method is general enough to be applied to two- and three-dimensional unstructured cells. Instead of defining a cell-point as the geometric average of its nodes (a cell-center), the cell-point is that which equalizes the triangular/tetrahedral area/volume in two/three dimensions. Examples are given.

  10. Precursor salt assisted syntheses of high-index faceted concave hexagon and nanorod-like polyoxometalates.

    PubMed

    Pal, Jaya; Ganguly, Mainak; Mondal, Chanchal; Negishi, Yuichi; Pal, Tarasankar

    2015-01-14

    This paper describes an effective method for a precursor salt assisted fabrication and reshaping of two different polyoxometalates [(NH4)2Cu(MoO4)2 (ACM) and Cu3(MoO4)2(OH)2 (CMOH)] into five distinctive shapes through straightforward and indirect routes. Explicit regulation of the structural arrangements of ACM and CMOH has been studied in detail with altered precursor salt concentration employing our laboratory developed modified hydrothermal (MHT) method. Morphologically different ACM 3D architectures are evolved with higher molybdate concentration, whereas 1D growth of CMOH is observed with increased copper concentration. Interesting morphological transformation of the products has been accomplished employing one precursor salt at a time without using any other foreign reagent. It has been proven that large ACMs become labile in the presence of incoming Cu(II) and NH4(+) ions of the precursor salts. A new strategy for the conversion of faceted ACMs (hexagonal plate, circular plate and hollow flower) to exclusive CMOH nanorods through a Cu(II) assisted reaction has been adopted. According to thermodynamic consideration, the synthesis of rare concave nanostructures with high index facet is still challenging due to their higher reactivity. In this study, concave hexagonal ACM with high index facet {hkl} has been successfully prepared for the first time from hexagonal ACM through simple etching with ammonium heptamolybdate (AHM), which is another precursor salt. Hexagonal ACM corrugates to a concave hexagon because of the higher reactivity of the {001} crystal plane than that of the {010} plane. It has been shown that high index facet exposed concave hexagonal ACM serves as a better catalyst for the photodegradation of dye than the other microstructures enclosed by low index facets.

  11. Development of a Stretchable Concave Imaging Membrane Mirror of Variable Focus

    DTIC Science & Technology

    1988-03-20

    experimental work for the future. Replacing heavy polished monolithic or segmented mirrors with lightweight holograms of those mirrors must be an attractive... monolithic mirrors. The problem is that the mirrors have to be very accurately supported and to the best of the writers knowledge have only obtained infra...systems, one monolithic and one an array, are described in references (26) and (27). An extremely interesting active concave plasic membrane mirror is that

  12. An extended magnetostatic Born-Infeld model with a concave lower order term

    SciTech Connect

    Chen, Jun; Pan, Xing-Bin

    2013-11-15

    This paper concerns an extended Born-Infeld model with a concave lower order term for the magnetostatic case. Three types of boundary value problems are considered: the boundary condition prescribing the tangential component of A, the natural boundary condition, and the boundary condition prescribing the tangential component of curl A. In each case we obtain existence and regularity of solutions for small boundary data.

  13. [A convex-concave contact lens for vitreoretinal operations with the BIOM].

    PubMed

    Eckardt, C; Wiechens, B

    1991-01-01

    A new convex-concave contact lens for wide-angle vitreoretinal surgery with the BIOM was developed. Placed on an eye, in which silicone oil is injected, it prevents the formation of an optically disturbing oil-water-film on the surface of the cornea. Thus the new contact lens leads to an essential improvement of the fundus view intraoperatively without affecting the optical properties of the BIOM.

  14. Simple proof of the concavity of the entropy power with respect to Gaussian noise

    NASA Technical Reports Server (NTRS)

    Dembo, Amir

    1989-01-01

    A very simple proof of M. H. Costa's result that the entropy power of Xt = X + N (O, tI) is concave in t, is derived as an immediate consequence of an inequality concerning Fisher information. This relationship between Fisher information and entropy is found to be useful for proving the central limit theorem. Thus, one who seeks new entropy inequalities should try first to find new inequalities about Fisher information, or at least to exploit the existing ones in new ways.

  15. LES of spatially developing turbulent boundary layer over a concave surface

    NASA Astrophysics Data System (ADS)

    Arolla, Sunil; Durbin, Paul

    2013-11-01

    We revisit the problem of spatially developing turbulent boundary layer over a concave surface. Unlike previous investigations, we simulate the combined effects of curvature-induced pressure gradients as well as streamline curvature on the turbulence. Our focus is on investigating the response of the turbulent boundary layer to the sudden onset of curvature and the destabilizing influence of concave surface in the presence of pressure gradients. This is of interest for evaluating the turbulence closure models. Numerical simulations have been performed using the large eddy simulation framework in OpenFOAM. The dynamic Smagorinsky model is used to account for the sub-grid scale stresses. A variant of the recycling and rescaling method is used to generate the inflow turbulence. At the beginning of the curve, the momentum thickness Reynolds number is 1300 and the ratio of boundary layer thickness to the radius of curvature is δ0 / R = 0 . 055 . The radial profiles of the mean velocity and turbulence statistics at different locations along the concave surface are presented. In addition, the secondary flow structures observed are reported.

  16. Technology for fabricating micro-lens arrays utilizing lithographically replicated concave resist patterns

    NASA Astrophysics Data System (ADS)

    Kobayashi, Noa; Sasaki, Ryunosuke; Horiuchi, Toshiyuki

    2016-05-01

    Lithography has been generally used for printing two-dimensional patterns on flat wafers. Recently, however, it is also applied to a three-dimensional patterning for fabricating various MEMS (Micro Electro Mechanical Systems) components. The purpose of this research is to develop a new method for fabricating micro-lens arrays. At first, resist (Tokyo Ohka Kogyo, PMER LA-900PM) mold patterns with densely arrayed square or hexagonal concaves were replicated by intentionally shifting the focal position of projection exposure. The size of resist-mold was 2 mm square, and the initial thickness of the resist was 10 μm. Next, the wafer with the concave resist patterns was cut into small chips, and each wafer chip was fixed at the bottom of a paper cup using an adhesive tape. Then the epoxy resin (Nissin resin, Crystal resin Neo) was poured on the concave resist-mold patterns, and the resin was coagulated. Afterward, the hardened resin was grooved along the wafer chip using a cutter knife, and the wafer chip with the resist-mold patterns was forcibly removed using a pair of tweezers. Finally, both sides of the resin block were polished, and the thickness was reduced. Although the transparency and roughness of the resin block surfaces should be improved, epoxy micro-lens arrays were certainly fabricated. The mean values of curvature radius and lens height were 28.3μm and 4.9 μm, respectively.

  17. The implementation of concave micro optical devices using a polymer dispensing technique

    NASA Astrophysics Data System (ADS)

    Hsiao, Sheng-Yi; Lee, Chih-Chun; Fang, Weileun

    2008-08-01

    This study demonstrates a novel approach to implementing a double-concave (DCV) microlens using a simple polymer dispensing and sucking process. The DCV microlens is implemented at room temperature using a commercially-available pneumatic-controlled polymer dispensing system. The DCV lens profile can be tuned by varying the volume of the dispensed polymer. It is also easy to integrate the present polymer DCV microlens with other suspended micromachined devices such as silicon nitride film and silicon-on-glass (SOG) micromachined structures. This study further employs the process for DCV to implement a concave mirror. The measurement results show a typical DCV lens (made of NOA63 polymer) with negative focal lengths of -1.42 mm (red laser) and -1.17 mm (blue laser), and a concave mirror with a focal length of 3.28 mm. Moreover, this study also demonstrates the integration of a DCV microlens with other optical components, such as plano-convex and double-convex lenses.

  18. Vorticity Dynamics of Cross-isobath Geostrophic Transport in the Stratified Steep and Concave Shelves

    NASA Astrophysics Data System (ADS)

    Jianping, G.; Hui, C. W.

    2016-02-01

    We investigated the variability and the physics of cross-isobath transport that lead to the formation of prominent upwelling centers in the steep shelf to the east of Hainan Island (EHI) and in the ambient shallow Gulf of Zhanjiang (GOZ). In situ measurements and a three-dimensional modeling showed that strengthened upslope transport of cold deep waters occurred in these two shelves, which are characterized by steep slope and concaving isobaths, respectively. The major driving force for these shoreward cross-isobath transports were not from the bottom frictional dynamics, but from the along-isobath pressure gradient force (PGF) as a result of the flow response to the variable shelf topography. The physical origins of the PGF of these prominent upwelling centers, however, were dynamically different. We found that the sources of the PGF were the Modified Joint Effect Baroclinicity and Relief (MJEBAR) due to importance of baroclinicity in the steep EHI and the net water-column stress curl in the concaving GOZ. The along-shelf geostrophic current that maintains the flow-topography interaction for the formation of the PGF was determined by the competing slope and baroclinic effects in EHI and by the cross-isobath changing bottom pressure in GOZ. Based on depth-integrated vorticity dynamics for a stratified and free-surface sea, this study illustrates the contrasting forcing functions of the three-dimensional circulation over the steep and shallow concaving shelves.

  19. Physical and numerical aspects of the high-speed unsteady flow around concave axisymmetric bodies

    NASA Astrophysics Data System (ADS)

    Panaras, Argyris; Drikakis, Dimitris

    2011-09-01

    The axisymmetric concave body is a typical configuration about which shock/shock interactions appear. Various shapes of axisymmetric concave bodies are used in a variety of applications in aeronautics, for example, axisymmetric jet inlets with conical centerbody, ballistic missiles drag reduction by spike, plasma or hot gas injection, parachutes for pilot-ejection capsules. However, it is well known that two distinct modes of instability appear around a concave body in the high-speed flow regime for a certain range of geometric parameters. These instabilities can cause undesirable effects such as severe vibration of the structure, heating and pressure loads. According to the experimental evidence, the unsteady flow is characterised by periodic radial inflation and collapse of the conical separation bubble formed around the forebody (pulsation). Various explanations have been given for the driving mechanism of the instabilities. In the present, merging of the leading explanations is done, and basic rules for the passive suppression of the instabilities are applied, in order to enforce their proposed driving. In addition, the effect of the flow initialisation method on the flow structure predicted by numerical simulations is examined. For certain configurations, bifurcation of the time-dependent flow has been found. This behaviour is explained with recourse to the phenomenon of hysteresis, which is an inherent feature of the examined flows.

  20. High-Speed Unsteady Flows around Concave Axisymmetric Bodies: Flow Instabilities and their Suppression

    NASA Astrophysics Data System (ADS)

    Panaras, A.; Drikakis, D.

    2009-01-01

    The axisymmetric concave body, i.e. a body in which the normals to its surface intersect, is a typical configuration about which shock/shock interactions appear. Various shapes of axisymmetric concave bodies are used in a variety of applications in aeronautics. For exampe: axisymmetric jet inlets with conical centerbody, ballistic missiles drag reduction by spike, plasma or hot gas injection, parachutes for pilot-ejection capsules. However, it is well known that two distinct modes of instability appear around a concave body in the high-speed flow regime, for a certain range of geometric parameters. These instabilities can cause undesirable effects such as severe vibration of the structure, heating and pressure loads. According to the experimental evidence, the unsteady flow is characterized by periodic radial inflation and collapse of the conical separation bubble formed around the forebody (pulsation). Various explanations have been given for the driving mechanism of the instabilities. They are based on interpretation of experimental results or on numerical simulation of the related flows. A merging of the leading explanations is done, and basic rules for the passive suppression of the instabilities are applied, in order to enforce the proposed driving mechanism of the instabilities. Most of the analysis is based on numerical simulations.

  1. Fabrication of a roller type PDMS stamp using SU-8 concave molds and its application for roll contact printing

    NASA Astrophysics Data System (ADS)

    Park, Jongho; Kim, Beomjoon

    2016-03-01

    Continuous fabrication of micropatterns at low-cost is attracting attention in various applications within industrial fields. To meet such demands, we have demonstrated a roll contact printing technique, using roller type polydimethylsiloxane (PDMS) stamps with roll-to-flat and roll-to-roll stages. Roller type PDMS stamps for roll contact printing were fabricated using a custom-made metal support and SU-8 microstructures fabricated on concave substrates as a mold. The molding/casting method which we developed here provided faster and easier fabrication than conventional methods for roller type stamps. Next, roll contact printing was performed using fabricated roller type PDMS stamps with roll-to-flat and roll-to-roll stages. Patterns with minimum widths of 3 μm and 2.1 μm were continuously fabricated for each stage, respectively. In addition, the relationship between applied pressures and dimensional changes of roll contact printed patterns was investigated. Finally, we confirmed that roll contact printing and the new fabrication method for roller stamps presented in this study demonstrated the feasibility for industrial applications.

  2. Imaging with Concave Large-Aperture Therapeutic Ultrasound Arrays Using Conventional Synthetic-Aperture Beamforming

    PubMed Central

    Wan, Yayun; Ebbini, Emad S.

    2009-01-01

    Several dual-mode ultrasound array (DMUA) systems are being investigated for potential use in image-guided surgery. In therapeutic mode, DMUAs generate pulsed or continuous-wave (CW) high-intensity focused ultrasound (HIFU) beams capable of generating localized therapeutic effects within the focal volume. In imaging mode, pulse-echo data can be collected from the DMUA elements to obtain B-mode images or other forms of feedback on the state of the target tissue before, during, and after the application of the therapeutic HIFU beam. Therapeutic and technological constraints give rise to special characteristics of therapeutic arrays. Specifically, DMUAs have concave apertures with low f-number values and are typically coarsely sampled using directive elements. These characteristics necessitate pre- and post-beamforming signal processing of echo data to improve the spatial and contrast resolution and maximize the image uniformity within the imaging field of view (IxFOV). We have recently developed and experimentally validated beamforming algorithms for concave large-aperture DMUAs with directive elements. Experimental validation was performed using a 1 MHz, 64-element, concave spherical aperture with 100 mm radius of curvature. The aperture was sampled in the lateral direction using elongated elements 1−λ×33.3‒ with 1.333‒−λ center-to-center spacing (λ is the wavelength). This resulted in f-number values of 0.8 and 2 in the azimuth and elevation directions, respectively. In this paper, we present a new DMUA design approach based on different sampling of the shared concave aperture to improve image quality while maintaining therapeutic performance. A pulse-wave (PW) simulation model using a modified version of the Field II program is used in this study. The model is used in generating pulse-echo data for synthetic-aperture (SA) beamforming for forming images of a variety of targets, e.g., wire arrays and speckle-generating cyst phantoms. To provide

  3. Imaging with concave large-aperture therapeutic ultrasound arrays using conventional synthetic-aperture beamforming.

    PubMed

    Wan, Yayun; Ebbini, Emad S

    2008-08-01

    Several dual-mode ultrasound array (DMUA) systems are being investigated for potential use in image- guided surgery. In therapeutic mode, DMUAs generate pulsed or continuous-wave (CW) high-intensity focused ultrasound (HIFU) beams capable of generating localized therapeutic effects within the focal volume. In imaging mode, pulse-echo data can be collected from the DMUA elements to obtain B-mode images or other forms of feedback on the state of the target tissue before, during, and after the application of the therapeutic HIFU beam. Therapeutic and technological constraints give rise to special characteristics of therapeutic arrays. Specifically, DMUAs have concave apertures with low f-number values and are typically coarsely sampled using directive elements. These characteristics necessitate pre- and post-beamforming signal processing of echo data to improve the spatial and contrast resolution and maximize the image uniformity within the imaging field of view (IxFOV). We have recently developed and experimentally validated beamforming algorithms for concave large-aperture DMUAs with directive elements. Experimental validation was performed using a 1 MHz, 64-element, concave spherical aperture with 100 mm radius of curvature. The aperture was sampled in the lateral direction using elongated elements 1-lambda x 33.3-lambda with 1.333-lambda center-to-center spacing (lambda is the wavelength). This resulted in f-number values of 0.8 and 2 in the azimuth and elevation directions, respectively. In this paper, we present a new DMUA design approach based on different sampling of the shared concave aperture to improve image quality while maintaining therapeutic performance. A pulse-wave (PW) simulation model using a modified version of the Field II program is used in this study. The model is used in generating pulse-echo data for synthetic-aperture (SA) beamforming for forming images of a variety of targets, e.g., wire arrays and speckle-generating cyst phantoms. To

  4. Three-dimensional metal-organic framework derived porous CoP3 concave polyhedrons as superior bifunctional electrocatalysts for the evolution of hydrogen and oxygen.

    PubMed

    Wu, Tianli; Pi, Mingyu; Wang, Xiaodeng; Zhang, Dingke; Chen, Shijian

    2017-01-18

    Developing low-cost and highly-efficient non-precious metal bifunctional electrocatalysts towards the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an attractively alternative strategy to solve the environmental pollution problems and energy demands. In this study, metal-organic framework (MOF) derived porous cobalt poly-phosphide (CoP3) concave polyhedrons are prepared and explored as superior bifunctional electrocatalysts for the HER and OER. The prepared MOF derived CoP3 concave polyhedrons show excellent electrocatalytic activity and stability towards the HER and OER in both acidic and alkaline media, with the Tafel slopes of 53 mV dec(-1) and 76 mV dec(-1) and a current density of 10 mA cm(-2) at the overpotentials of -78 and 343 mV for the HER and OER, respectively, which are remarkably superior to those of the transition metal phosphides (TMPs) and comparable to those of the commercial precious metal catalysts. In addition, they also offer efficient catalytic activities and durabilities under neutral and basic conditions for the HER. The results of our study may shed light on the direction towards highly efficient bifunctional TMP electrocatalysts with high phosphorous component.

  5. Alternative hypotheses to explain why biodiversity-ecosystem functioning relationships are concave-up in some natural ecosystems but concave-down in manipulative experiments

    PubMed Central

    Mora, Camilo; Danovaro, Roberto; Loreau, Michel

    2014-01-01

    Recent studies of the relationship between biodiversity and functioning in marine ecosystems have yielded non-saturating patterns that contrast sharply with the results of experimental studies, where ecosystem functioning rapidly saturates with increases in biodiversity. Here we provide a simple theoretical framework of three alternative hypotheses that, individually or combined, are likely to explain this contrast: i) the use of functional richness instead of species richness, ii) an increased production efficiency of species in producing biomass when more ecological interactions are present, and iii) the fact that communities are likely assembled in an ordered succession of species from low to high ecological efficiency. Our results provide theoretical support for concave-up biodiversity-ecosystem functioning relationships in natural ecosystems and confirm that the loss of species can have substantially larger effects on the functioning of natural ecosystems than anticipated from controlled manipulative experiments. PMID:24962477

  6. Alternative hypotheses to explain why biodiversity-ecosystem functioning relationships are concave-up in some natural ecosystems but concave-down in manipulative experiments.

    PubMed

    Mora, Camilo; Danovaro, Roberto; Loreau, Michel

    2014-06-25

    Recent studies of the relationship between biodiversity and functioning in marine ecosystems have yielded non-saturating patterns that contrast sharply with the results of experimental studies, where ecosystem functioning rapidly saturates with increases in biodiversity. Here we provide a simple theoretical framework of three alternative hypotheses that, individually or combined, are likely to explain this contrast: i) the use of functional richness instead of species richness, ii) an increased production efficiency of species in producing biomass when more ecological interactions are present, and iii) the fact that communities are likely assembled in an ordered succession of species from low to high ecological efficiency. Our results provide theoretical support for concave-up biodiversity-ecosystem functioning relationships in natural ecosystems and confirm that the loss of species can have substantially larger effects on the functioning of natural ecosystems than anticipated from controlled manipulative experiments.

  7. Semiconductor light-emitting devices having concave microstructures providing improved light extraction efficiency and method for producing same

    DOEpatents

    Tansu, Nelson; Gilchrist, James F; Ee, Yik-Khoon; Kumnorkaew, Pisist

    2013-11-19

    A conventional semiconductor LED is modified to include a microlens layer over its light-emitting surface. The LED may have an active layer including at least one quantum well layer of InGaN and GaN. The microlens layer includes a plurality of concave microstructures that cause light rays emanating from the LED to diffuse outwardly, leading to an increase in the light extraction efficiency of the LED. The concave microstructures may be arranged in a substantially uniform array, such as a close-packed hexagonal array. The microlens layer is preferably constructed of curable material, such as polydimethylsiloxane (PDMS), and is formed by soft-lithography imprinting by contacting fluid material of the microlens layer with a template bearing a monolayer of homogeneous microsphere crystals, to cause concave impressions, and then curing the material to fix the concave microstructures in the microlens layer and provide relatively uniform surface roughness.

  8. Efficient proton acceleration and focusing by an ultraintense laser interacting with a parabolic double concave target with an extended rear

    SciTech Connect

    Bake, Muhammad Ali; Xie, Bai-Song; Aimidula, Aimierding; Wang, Hong-Yu

    2013-07-15

    A new scheme for acceleration and focusing of protons via an improved parabolic double concave target irradiated by an ultraintense laser pulse is proposed. When an intense laser pulse illuminates a concave target, the hot electrons are concentrated on the focal region of the rear cavity and they form a strong space-charge-separation field, which accelerates the protons. For a simple concave target, the proton energy spectrum becomes very broad outside the rear cavity because of transverse divergence of the electromagnetic fields. However, particle-in-cell simulations show that, when the concave target has an extended rear, the hot electrons along the wall surface induce a transverse focusing sheath field, resulting in a clear enhancement of proton focusing, which makes the lower proton energy spread, while, leads to a little reduction of the proton bunch peak energy.

  9. Seamless lamination of a concave-convex architecture with single-layer graphene

    NASA Astrophysics Data System (ADS)

    Park, Ji-Hoon; Lim, Taekyung; Baik, Jaeyoon; Seo, Keumyoung; Moon, Youngkwon; Park, Noejung; Shin, Hyun-Joon; Kyu Kwak, Sang; Ju, Sanghyun; Real Ahn, Joung

    2015-10-01

    Graphene has been used as an electrode and channel material in electronic devices because of its superior physical properties. Recently, electronic devices have changed from a planar to a complicated three-dimensional (3D) geometry to overcome the limitations of planar devices. The evolution of electronic devices requires that graphene be adaptable to a 3D substrate. Here, we demonstrate that chemical-vapor-deposited single-layer graphene can be transferred onto a silicon dioxide substrate with a 3D geometry, such as a concave-convex architecture. A variety of silicon dioxide concave-convex architectures were uniformly and seamlessly laminated with graphene using a thermal treatment. The planar graphene was stretched to cover the concave-convex architecture, and the resulting strain on the curved graphene was spatially resolved by confocal Raman spectroscopy; molecular dynamic simulations were also conducted and supported the observations. Changes in electrical resistivity caused by the spatially varying strain induced as the graphene-silicon dioxide laminate varies dimensionally from 2D to 3D were measured by using a four-point probe. The resistivity measurements suggest that the electrical resistivity can be systematically controlled by the 3D geometry of the graphene-silicon dioxide laminate. This 3D graphene-insulator laminate will broaden the range of graphene applications beyond planar structures to 3D materials.Graphene has been used as an electrode and channel material in electronic devices because of its superior physical properties. Recently, electronic devices have changed from a planar to a complicated three-dimensional (3D) geometry to overcome the limitations of planar devices. The evolution of electronic devices requires that graphene be adaptable to a 3D substrate. Here, we demonstrate that chemical-vapor-deposited single-layer graphene can be transferred onto a silicon dioxide substrate with a 3D geometry, such as a concave-convex architecture. A

  10. Measurements of the Effectiveness of Concave Spherical Dimples for Enhancement of Hot-gas Side Heat Transfer (Preprint)

    DTIC Science & Technology

    2008-12-04

    Effectiveness of Concave Spherical Dimples for Enhancement of Hot-gas Side Heat Transfer (Preprint) 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...the heat transfer enhancement effects of concave spherical dimples have been performed under hydrogen- oxygen hot-fire conditions in a subscale...Additional quantitiative results will included in the form of heat transfer coefficients and Stanton number.) Enhancements of 15-82% relative to a smooth

  11. Concave Pd-Pt Core-Shell Nanocrystals with Ultrathin Pt Shell Feature and Enhanced Catalytic Performance.

    PubMed

    Zhang, Ying; Bu, Lingzheng; Jiang, Kezhu; Guo, Shaojun; Huang, Xiaoqing

    2016-02-10

    One-pot creation of unique concave Pd-Pt core-shell polyhedra has been developed for the first time using an efficient approach. Due to the concave feature and ultrathin Pt shell, the created Pd-Pt core-shell polyhedra exhibit enhanced catalytic performance in both the electrooxidation of methanol and hydrogenation of nitrobenzene, as compared with commercial Pt black and Pd black catalysts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of a concave grid mesh in a carbon nanotube-based field emission X-ray source

    SciTech Connect

    Kim, Hyun Suk; Castro, Edward Joseph D.; Lee, Choong Hun

    2014-10-15

    Highlights: • Successful design using a concave grid mesh for the focusing electron. • Much better X-ray image due to the concave grid mesh. • Higher anode current efficiency using the concave grid mesh versus a flat grid mesh. - Abstract: This study introduces a simple approach to improve the X-ray image quality produced by the carbon nanotube (CNT) field emitter X-ray source by altering the geometrical shape of the grid mesh from the conventional flat shape to a concave one in a typical triode structure. The concave shape of the grid electrode increases the effective number of the grid cells in the mesh, which exerted an electric field in the direction of the emitted electrons, thereby increasing the emission current reaching the anode. Furthermore, the curved mesh (concave grid mesh), which was responsible for the extraction of electrons from the field emitter, exhibited a focusing effect on the electron beam trajectory thereby, reducing the focal spot size impinging on the anode and resulted in a better spatial resolution of the X-ray images produced.

  13. Triangle and concave pentagon electrodes for an improved broadband frequency response of stripline beam position monitors

    NASA Astrophysics Data System (ADS)

    Shobuda, Yoshihiro; Chin, Yong Ho; Takata, Koji; Toyama, Takeshi; Nakamura, Keigo

    2016-02-01

    The frequency domain performance of a stripline beam position monitor depends largely on the longitudinal shape of its electrode. Some shapes other than a conventional rectangle have been proposed and tested. To attain a good impedance matching along the electrode, they need to be precisely bent down toward their downstream in proportion to their width. This is a considerable task, and a failure to comply with it will result in a large distortion of the frequency-domain transfer function from the ideal one due to unwanted signal reflections. In this report, we first propose a triangle electrode for easy fabrication and setup: it only requires that a triangularly cut flat electrode will be placed in a chamber while being obliquely inclined toward the downstream port. Theoretical and simulation results show that the simple triangle electrode has a remarkably flatter frequency response than the rectangle one. The frequency response, in particular at high frequencies, can be further improved by attaching an "apron" plate, perpendicular to the upstream edge of the electrode. The overshooting of the frequency response at low frequency can be eliminated by replacing the straight sidelines of the triangle by three-point polylines (with a result that the triangle is transformed to a concave pentagon). The concave pentagon electrode needs to be bent only once at the middle point of the polylines for a good impedance matching and thus its fabrication and setup remain to be easy. Rf measurements for the various electrode shapes have been carried out. We found that the concave pentagon electrode achieves a wide and flat frequency response up to about 4 GHz for the J-PARC Main Ring (MR).

  14. Large eddy simulation of a boundary layer with concave streamwise curvature

    NASA Technical Reports Server (NTRS)

    Lund, Thomas S.

    1993-01-01

    One of the most exciting recent developments in the field of large eddy simulation (LES) is the dynamic subgrid-scale model. The dynamic model concept is a general procedure for evaluating model constants by sampling a band of the smallest scales actually resolved in the simulation. To date, the procedure has been used primarily in conjunction with the Smagorinsky model. The dynamic procedure has the advantage that the value of the model constant need not be specified a priori, but rather is calculated as a function of space and time as the simulation progresses. This feature makes the dynamic model especially attractive for flows in complex geometries where it is difficult or impossible to calibrate model constants. The dynamic model was highly successful in benchmark tests involving homogeneous and channel flows. Having demonstrated the potential of the dynamic model in these simple flows, the overall direction of the LES effort at CTR shifted toward an evaluation of the model in more complex situations. The current test cases are basic engineering-type flows for which Reynolds averaged approaches were unable to model the turbulence to within engineering accuracy. Flows currently under investigation include a backward-facing step, wake behind a circular cylinder, airfoil at high angles of attack, separated flow in a diffuser, and boundary layer over a concave surface. Preliminary results from the backward-facing step and cylinder wake simulations are encouraging. Progress on the LES of a boundary layer on a concave surface is discussed. Although the geometry of a concave wall is not very complex, the boundary layer that develops on its surface is difficult to model due to the presence of streamwise Taylor-Gortler vortices. These vortices arise as a result of a centrifugal instability associated with the convex curvature.

  15. Limit Distribution Theory for Maximum Likelihood Estimation of a Log-Concave Density.

    PubMed

    Balabdaoui, Fadoua; Rufibach, Kaspar; Wellner, Jon A

    2009-06-01

    We find limiting distributions of the nonparametric maximum likelihood estimator (MLE) of a log-concave density, i.e. a density of the form f(0) = exp varphi(0) where varphi(0) is a concave function on R. Existence, form, characterizations and uniform rates of convergence of the MLE are given by Rufibach (2006) and Dümbgen and Rufibach (2007). The characterization of the log-concave MLE in terms of distribution functions is the same (up to sign) as the characterization of the least squares estimator of a convex density on [0, infinity) as studied by Groeneboom, Jongbloed and Wellner (2001b). We use this connection to show that the limiting distributions of the MLE and its derivative are, under comparable smoothness assumptions, the same (up to sign) as in the convex density estimation problem. In particular, changing the smoothness assumptions of Groeneboom, Jongbloed and Wellner (2001b) slightly by allowing some higher derivatives to vanish at the point of interest, we find that the pointwise limiting distributions depend on the second and third derivatives at 0 of H(k), the "lower invelope" of an integrated Brownian motion process minus a drift term depending on the number of vanishing derivatives of varphi(0) = log f(0) at the point of interest. We also establish the limiting distribution of the resulting estimator of the mode M(f(0)) and establish a new local asymptotic minimax lower bound which shows the optimality of our mode estimator in terms of both rate of convergence and dependence of constants on population values.

  16. Free-stream turbulence and concave curvature effects on heated, transitional boundary layers, volume 1

    NASA Technical Reports Server (NTRS)

    Kim, J.; Simon, T. W.

    1991-01-01

    An experimental investigation of the transition process on flat-plate and concave curved-wall boundary layers for various free-streem turbulence levels was performed. Where possible, sampling according to the intermittency function was made. Such sampling allowed segregation of the signal into two types of behavior: laminar-like and turbulent-like. The results from the investigation are discussed. Documentation is presented in two volumes. Volume one contains the text of the report including figures and supporting appendices. Volume two contains data reduction program listings and tabulated data.

  17. A Study of Laminar Separation Bubble in the Concave Region of an Airfoil Using Laser Velocimetry

    NASA Technical Reports Server (NTRS)

    Mangalam, Sivaramakrishnan; Meyers, James F.; Dagenhart, John R.; Harvey, William D.

    1985-01-01

    Laser velocimetry (LV) was used to study the nature of laminar separation bubbles in the concave region of a 1.83-meter airfoil model which was tested in the NASA Langley Low Turbulence Pressure Tunnel. Three component, coincident data from LV measurements including histograms of particle velocity, mean velocity profiles, turbulence intensity, and Reynolds stresses within the shear layer were used to determine the locations of laminar separation, transition, and turbulent reattachment. Boundary-layer parameters determined from velocity profiles were used to compare the results with existing empirical relations for describing the laminar separation bubble.

  18. Waves and rays in plano-concave laser cavities: II. A semiclassical approach

    NASA Astrophysics Data System (ADS)

    Pascal, A.; Bittner, S.; Dietz, B.; Trabattoni, A.; Ulysse, C.; Romanelli, M.; Brunel, M.; Zyss, J.; Lebental, M.

    2017-05-01

    This second paper on the Fabry-Perot cavity presents a semi-classical approach, which means that we consider the transition from wave optics to geometrical optics. The basic concepts are the periodic orbits and their stability. For the plano-concave Fabry-Perot cavity in the paraxial approximation, the derivation of the trace formula demonstrates that the spectrum is based only on the axial periodic orbit and its repetitions. Experiments with microlasers illustrate the relation to periodic orbits. The methods presented in this paper are not limited to laser cavities and can be applied to a large range of wave systems.

  19. The Effects of Streamwise Concave Curvature on Turbulent Boundary Layer Structure.

    DTIC Science & Technology

    1982-06-01

    proceeds downstream. 3.1.4 ilauser Plots In order to determine if a log region existed in the boundary layer on a concave wall, the mean velocity was plotted...in the 760 cm profile. However, on the basis of the Clauser method, the slope of the log region in the profile at 300 implies a lower skin fric- tion...r -. .... -- __n_ i_ ___ - m a_____ •___ m i l tentatively conclude that the usual correlation relating the log region with the skin friction may

  20. Change of blaze wavelength as a function of position on the surface of a concave grating

    NASA Technical Reports Server (NTRS)

    Michels, D. J.

    1974-01-01

    Conventional ruling of a concave diffraction grating with blaze angle constant relative to the optical axis produces a grating whose blaze wavelength changes continuously with displacement across the face of the ruled area. A simple explanation of the effect is given in terms of geometrical optics, and quantitative expressions are developed that relate the expected blaze-wavelength shift to the grating constant and aperture ratio. Results are compared with experimental efficiency measurements, and the magnitude of the effect in a typical grating is discussed.

  1. Hollow and Concave Nanoparticles via Preferential Oxidation of the Core in Colloidal Core/Shell Nanocrystals

    PubMed Central

    2014-01-01

    Hollow and concave nanocrystals find applications in many fields, and their fabrication can follow different possible mechanisms. We report a new route to these nanostructures that exploits the oxidation of Cu2–xSe/Cu2–xS core/shell nanocrystals with various etchants. Even though the Cu2–xSe core is encased in a thick Cu2–xS shell, the initial effect of oxidation is the creation of a void in the core. This is rationalized in terms of diffusion of Cu+ ions and electrons from the core to the shell (and from there to the solution). Differently from the classical Kirkendall effect, which entails an imbalance between in-diffusion and out-diffusion of two different species across an interface, the present mechanism can be considered as a limiting case of such effect and is triggered by the stronger tendency of Cu2–xSe over Cu2–xS toward oxidation and by fast Cu+ diffusion in copper chalcogenides. As the oxidation progresses, expansion of the inner void erodes the entire Cu2–xSe core, accompanied by etching and partial collapse of the shell, yielding Cu2–xSySe1–y concave particles. PMID:24866716

  2. Study of rounded concave and sharp edge convex corners undercutting in CMOS compatible anisotropic etchants

    NASA Astrophysics Data System (ADS)

    Pal, Prem; Sato, Kazuo; Gosalvez, Miguel A.; Shikida, Mitsuhiro

    2007-11-01

    In this paper, we have studied the undercutting at rounded concave and sharp convex corners in (1 0 0)-silicon wafers using a complementary metal-oxide semiconductor (CMOS) compatible tetramethyl ammonium hydroxide (TMAH) solution with and without surfactant. In order to minimize the undercutting at both corner types while keeping reasonable etch rates, smooth etched-surfaces and CMOS compatibility, the non-ionic surfactant NC-200 that contains 100% polyoxyethylene-alkyl-phenyl-ether is considered. The effect of concentration and etching temperature is studied using 10, 20 and 25 wt% TMAH solutions at 60, 70 and 80 °C. When NC-200 at 0.1% of the total volume of the etchant is used, the undercutting ratio at both rounded concave and sharp convex corners is beneficially reduced as the etchant concentration is increased while, simultaneously, the etch rate increases. This is the opposite trend to the etch characteristics of pure TMAH. In addition, the rough etched surface morphology at low concentration is also improved by using NC-200.

  3. AUTOMATED CELL COUNTING AND CLUSTER SEGMENTATION USING CONCAVITY DETECTION AND ELLIPSE FITTING TECHNIQUES

    PubMed Central

    Kothari, Sonal; Chaudry, Qaiser; Wang, May D

    2016-01-01

    This paper presents a novel, fast and semi-automatic method for accurate cell cluster segmentation and cell counting of digital tissue image samples. In pathological conditions, complex cell clusters are a prominent feature in tissue samples. Segmentation of these clusters is a major challenge for development of an accurate cell counting methodology. We address the issue of cluster segmentation by following a three step process. The first step involves pre-processing required to obtain the appropriate nuclei cluster boundary image from the RGB tissue samples. The second step involves concavity detection at the edge of a cluster to find the points of overlap between two nuclei. The third step involves segmentation at these concavities by using an ellipse-fitting technique. Once the clusters are segmented, individual nuclei are counted to give the cell count. The method was tested on four different types of cancerous tissue samples and shows promising results with a low percentage error, high true positive rate and low false discovery rate.

  4. New optical mountings of the spectral devices with concave diffraction gratings and high entrance slit

    NASA Astrophysics Data System (ADS)

    Sokolova, Elena A.; Reyes Cortes, Santiago D.

    1996-11-01

    The concave diffraction grating is both the dispersive and the focusing element at the same time. It can be the only optical unit of monochromator or polychromator. Using the concave diffraction gratings with nonequidistant and curved grooves gives the possibility for correction of the aberrations in the useful region of spectrum and provides the devices with determined focal surfaces. To increase the height of the entrance slit of the spectroscopic device we have to eliminate the first and the second-order astigmatism aberrations. Consideration of this type of aberration is very important now in view of the new types of spectral devices using fiber optics and multielement detectors being developed. These new elements allow us to register the spectrum of extended objects or a number of spectrums simultaneously. For the case of the double monochromator we noticed, that the second-order astigmatism can be completely eliminated if the second part of the double monochromator is equivalent to its first part, but the ray tracing is inverse. The experiment on the mathematical model of the double monochromator confirms this idea. For the case of polychromator or CCD spectrometer we can compensate that aberrations using the illumination system, consists of the spherical mirror. The angle of incidence of the light to the mirror is calculated such a way, that the astigmatism of the grating is compensated by the astigmatism of the mirror.

  5. Packet marking function of active queue management mechanism: should it be linear, concave, or convex?

    NASA Astrophysics Data System (ADS)

    Ohsaki, Hiroyuki; Murata, Masayuki

    2004-09-01

    Recently, several gateway-based congestion control mechanisms have been proposed to support the end-to-end congestion control mechanism of TCP (Transmission Control Protocol). In this paper, we focus on RED (Random Early Detection), which is a promising gateway-based congestion control mechanism. RED randomly drops an arriving packet with a probability proportional to its average queue length (i.e., the number of packets in the buffer). However, it is still unclear whether the packet marking function of RED is optimal or not. In this paper, we investigate what type of packet marking function, which determines the packet marking probability from the average queue length, is suitable from the viewpoint of both steady state and transient state performances. Presenting several numerical examples, we investigate the advantages and disadvantages of three packet marking functions: linear, concave, and convex. We show that, although the average queue length in the steady state becomes larger, use of a concave function improves the transient behavior of RED and also realizes robustness against network status changes such as variation in the number of active TCP connections.

  6. L2CXCV: A Fortran 77 package for least squares convex/concave data smoothing

    NASA Astrophysics Data System (ADS)

    Demetriou, I. C.

    2006-04-01

    Fortran 77 software is given for least squares smoothing to data values contaminated by random errors subject to one sign change in the second divided differences of the smoothed values, where the location of the sign change is also unknown of the optimization problem. A highly useful description of the constraints is that they follow from the assumption of initially increasing and subsequently decreasing rates of change, or vice versa, of the process considered. The underlying algorithm partitions the data into two disjoint sets of adjacent data and calculates the required fit by solving a strictly convex quadratic programming problem for each set. The piecewise linear interpolant to the fit is convex on the first set and concave on the other one. The partition into suitable sets is achieved by a finite iterative algorithm, which is made quite efficient because of the interactions of the quadratic programming problems on consecutive data. The algorithm obtains the solution by employing no more quadratic programming calculations over subranges of data than twice the number of the divided differences constraints. The quadratic programming technique makes use of active sets and takes advantage of a B-spline representation of the smoothed values that allows some efficient updating procedures. The entire code required to implement the method is 2920 Fortran lines. The package has been tested on a variety of data sets and it has performed very efficiently, terminating in an overall number of active set changes over subranges of data that is only proportional to the number of data. The results suggest that the package can be used for very large numbers of data values. Some examples with output are provided to help new users and exhibit certain features of the software. Important applications of the smoothing technique may be found in calculating a sigmoid approximation, which is a common topic in various contexts in applications in disciplines like physics, economics

  7. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Surface Micromachined Adjustable Micro-Concave Mirror for Bio-Detection Applications

    NASA Astrophysics Data System (ADS)

    Kuo, Ju-Nan; Chen, Wei-Lun; Jywe, Wen-Yuh

    2009-08-01

    We present a bio-detection system integrated with an adjustable micro-concave mirror. The bio-detection system consists of an adjustable micro-concave mirror, micro flow cytometer chip and optical detection module. The adjustable micro-concave mirror can be fabricated with ease using commercially available MEMS foundry services (such as multiuser MEMS processes, MUMPs) and its curvature can be controlled utilizing thermal or electrical effects. Experimental results show that focal lengths of the micro-concave mirror ranging from 313.5 to 2275.0 μm are achieved. The adjustable micro-concave mirror can be used to increase the efficiency of optical detection and provide a high signal-to-noise ratio. The developed micro-concave mirror is integrated with a micro flow cytometer for cell counting applications. Successful counting of fluorescent-labeled beads is demonstrated using the developed method.

  8. 3D Quantification of Low-Coordinate Surface Atom Density: Bridging Catalytic Activity to Concave Facets of Nanocatalysts in Fuel Cells.

    PubMed

    Xia, Ye; Zhong, Xiaoyan; Ke, Xiaoxing; Zhang, Gui-Rong; Cheng, Zhiying; Xu, Bo-Qing

    2016-12-01

    A protocol to quantify the distribution of surface atoms of concave nanocatalysts according to their coordination number is proposed. The 3D surface of an Au@Pd concave nanocube is reconstructed and segmented. The crystallographic coordinates and low-coordinate surface atom densities of the concave facets are determined. The result shows that 32% of the surface atoms are low-coordinated, which may contribute to the high activity.

  9. Phenotypic characteristics of adolescents with concave and convex facial profiles - The National Health Examination Survey.

    PubMed

    Hujoel, P P; Bollen, A-M; Yuen, K C J; Hujoel, I A

    2016-10-01

    It has been suggested that facial traits are informative on the inherited susceptibility to tuberculosis and obesity, two current global health issues. Our aim was to compare the phenotypic characteristics of adolescents with dental markers for a concave (n=420), a convex (n=978), and a straight (n=3542) facial profile in a nationally representative sample of United States adolescents. The results show that adolescents with a concave facial profile, when compared to a straight facial profile, had an increased waist-to-height ratio (Δ, 1.1 [95% CI 0.5-1.7], p<0.003) and an increased acne prevalence (OR, 1.5 [95% CI 1.2-1.9], p<0.001). Adolescents with a convex facial profile, when compared to a straight facial profile, had an increased prevalence of tuberculosis (OR, 4.3 [95% CI 1.4-13.1], p<0.02), increased ectomorphy (Δ, 0.3 [95% CI 0.2-0.4], p<0.0001), increased left-handedness (OR, 1.4 [95% CI 1.1-1.7], p<0.007), increased color-blindness (OR, 1.7 [95% CI 1.3-2.3], p<0.004), and rhesus ee phenotype (OR, 1.3 [95% CI 1.1-1.5], p<0.008). Adolescents with a concave facial profile, when compared to a convex profile, had increased mesomorphy (Δ, 1.3 [95% CI 1.1-1.5], p<0.0001), increased endomorphy (Δ, 0.5 [95% CI 0.4-0.6], p<0.0001), lower ectomorphy (Δ, 0.5 [95% CI 0.4-0.6], p<0.0001), and lower vocabulary test scores (Δ, 2.3 [95% CI 0.8-3.8], p<0.008). It is concluded that population-based survey data confirm that distinct facial features are associated with distinct somatotypes and distinct disease susceptibilities. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. A design method based on photonic crystal theory for Bragg concave diffraction grating

    NASA Astrophysics Data System (ADS)

    Du, Bingzheng; Zhu, Jingping; Mao, Yuzheng; Li, Bao; Zhang, Yunyao; Hou, Xun

    2017-02-01

    A design method based on one-dimensional photonic crystal theory (1-D PC theory) is presented to design Bragg concave diffraction grating (Bragg-CDG) for the demultiplexer. With this design method, the reflection condition calculated by the 1-D PC theory can be matched perfectly with the diffraction condition. As a result, the shift of central wavelength of diffraction spectra can be improved, while keeping high diffraction efficiency. Performances of Bragg-CDG for TE and TM-mode are investigated, and the simulation results are consistent with the 1-D PC theory. This design method is expected to be applied to improve the accuracy and efficiency of Bragg-CDG after further research.

  11. Myelinated nerve bundles developed on the plano-concave fibers containing nerve conduit.

    PubMed

    Huang, Wei-Chin; Liao, Jiunn-Der; Lin, Chou-Ching K; Ju, Ming-Shaung

    2012-12-01

    Morphologically and chemically modified plano-concave fibers (PCFs) are designed as a unit of guided channels for supporting Schwann cells to facilitate mass transport and promote nerve regeneration. The surface-modified PCFs are imprinted with linearly patterned grooves (LPGs) to guide adherent Schwann cell elongation and axon extension. After being cocultured with PC12 neuron-like cells, Schwann cells differentiate into the myelinated type and interact with PC12 axons. The myelinated axons aggregate as a linear bundle and extend along the direction of LPGs on a PCF. The cross section of a myelin structure is examined using a transmission electron microscope. The PCFs can potentially bridge gaps in injured nerves, improving the therapeutic efficacy of nerve regeneration. Copyright © 2012 Wiley Periodicals, Inc.

  12. [Automatic segmentation of clustered breast cancer cells based on modified watershed algorithm and concavity points searching].

    PubMed

    Tong, Zhen; Pu, Lixin; Dong, Fangjie

    2013-08-01

    As a common malignant tumor, breast cancer has seriously affected women's physical and psychological health even threatened their lives. Breast cancer has even begun to show a gradual trend of high incidence in some places in the world. As a kind of common pathological assist diagnosis technique, immunohistochemical technique plays an important role in the diagnosis of breast cancer. Usually, Pathologists isolate positive cells from the stained specimen which were processed by immunohistochemical technique and calculate the ratio of positive cells which is a core indicator of breast cancer in diagnosis. In this paper, we present a new algorithm which was based on modified watershed algorithm and concavity points searching to identify the positive cells and segment the clustered cells automatically, and then realize automatic counting. By comparison of the results of our experiments with those of other methods, our method can exactly segment the clustered cells without losing any geometrical cell features and give the exact number of separating cells.

  13. Stability and control of compressible flows over a surface with concave-conves curvature

    NASA Technical Reports Server (NTRS)

    Maestrello, L.; Bayliss, A.; Parikh, P.; Turkel, E.

    1986-01-01

    The active control of spatially unstable disturbances in a laminar, two-dimensional, compressible boundary layer over a curved surface is numerically simulated. The control is effected by localized time-periodic surface heating. We consider two similar surfaces of different heights with concave-convex curvature. In one, the height is sufficiently large so that the favorable pressure gradient is sufficient to stabilize a particular disturbance. In the other case the pressure gradient induced by the curvature is destabilizing. It is shown that by using active control that the disturbance can be stabilized. The results demonstrate that the curvature induced mean pressure gradient significantly enhances the receptivity of the flow localized time-periodic surface heating and that this is a potentially viable mechanism in air.

  14. Chemocavity: specific concavity in protein reserved for the binding of biologically functional small molecules.

    PubMed

    Soga, Shinji; Shirai, Hiroki; Kobori, Masato; Hirayama, Noriaki

    2008-08-01

    The idea that there should be a specific site on a protein for a particular functional small molecule is widespread. It is, however, usually not so easy to understand what characteristics of the site determine the binding ability of the functional small molecule. We have focused on the concurrence rate of the 20 standard amino acids at such binding sites. In order to correlate the concurrence rate and the specific binding site, we have analyzed high-quality X-ray structures of complexes between proteins and small molecules. A novel index characterizing the binding site based on the concurrency rate has been introduced. Using this index we have identified that there is a specific concavity designated as a chemocavity where a specific group of small molecules, i.e., canonical molecular group, is highly inclined to be bound. This study has demonstrated that a chemocavity is reserved for a specific canonical molecular group, and the prevalent idea has been confirmed.

  15. Detection and separation of overlapping cells based on contour concavity for Leishmania images.

    PubMed

    Neves, João C; Castro, Helena; Tomás, Ana; Coimbra, Miguel; Proença, Hugo

    2014-06-01

    Life scientists often must count cells in microscopy images, which is a tedious and time-consuming task. Automatic approaches present a solution to this problem. Several procedures have been devised for this task, but the majority suffer from performance degradation in the case of cell overlap. In this article, we propose a method to determine the positions of macrophages and parasites in fluorescence images of Leishmania-infected macrophages. The proposed strategy is primarily based on blob detection, clustering, and separation using concave regions of the cells' contours. In comparison with the approaches of Nogueira (Master's thesis, Department of University of Porto Computer Science, 2011) and Leal et al. (Proceedings of the 9th international conference on Image Analysis and Recognition, Vol. II, ICIAR'12. Berlin, Heidelberg: Springer-Verlag; 2012. pp. 432-439), which also addressed this type of image, we conclude that the proposed methodology achieves better performance in the automatic annotation of Leishmania infections.

  16. One algorithm for branch and bound method for solving concave optimization problem

    NASA Astrophysics Data System (ADS)

    Andrianova, A. A.; Korepanova, A. A.; Halilova, I. F.

    2016-11-01

    The article describes the algorithm for branch and bound method for solving the concave programming problem, which is based on the idea of similarity the necessary and sufficient conditions of optimum for the original problem and for a convex programming problem with another feasible set and reverse the sign of the objective function. To find the feasible set of the equivalent convex programming problem we construct an algorithm using the idea of the branch and bound method. We formulate various branching techniques and discusses the construction of the lower objective function evaluations for the node of the decision tree. The article discusses the results of experiments of this algorithm for some famous test problems of a particular form.

  17. Analytical prediction of the transition from Mach to regular reflection over cylindrical concave wedges

    NASA Astrophysics Data System (ADS)

    Ben-Dor, G.; Takayama, K.

    1985-09-01

    Two formulas, based on analytical considerations, which are capable of predicting the wedge angle of transition from Mach to regular reflection over cylindrical concave wedges, are developed. They are derived using Hornung, Oertel and Sandeman's (1979) conclusion that a Mach reflection can exist only if the corner-generated signals can catch up with the incident shock wave. The good agreement between the present models and the experimental results confirm the concept of Hornung et al. (1979). The predictions of these models are in better agreement with experimental results than the predictions of Itoh, Okazaki and Itaya's (1981) model. The present models are very simple to use and apply, but like the model of Itoh et al. (1981), they also lack the ability to account for the dependenceof the transition angle on the radius of curvature of the cylindrical wedge.

  18. Calculation of Isodose Curves for Cca and Ccb Concave Eye Applicators

    NASA Astrophysics Data System (ADS)

    Mowlavi, Ali Asghar; Yazdani, Majed

    BEBIG Ruthenium-106 ophthalmic plaques have been used for treatment of uveal melanoma, retinoblastoma, melanoma of the iris and other special applications for more than 30 years. The plaques consist of a thin film of Ru-106, a beta emitter encapsulated in pure silver. Simulations of small concave applicators CCA and CCB, manufactured by Bebig, were performed using Monte Carlo MCNP4C code which allows for description of the applicator (geometry and materials) in detail. Electrons are emitted from the 106Ru nuclei isotropically with initial energy randomly sampled from the corresponding Fermi spectra and with initial positions uniformly distributed on the radioactive layer. In this work, relative doses were calculated in soft tissue phantom near the active layer. Isodose curves for CCA and CCB eye applicators were determined. Our calculated data agrees well with the measured phantom data reported in literature.

  19. Free-stream turbulence and concave curvature effects on heated, transitional boundary layers

    NASA Technical Reports Server (NTRS)

    Kim, J.; Simon, T. W.

    1991-01-01

    An experimental investigation of the transition process on flat-plate and concave curved-wall boundary layers for various free-stream turbulence levels was performed. Results show that for transition of a flat-plate, the two forms of boundary layer behavior, identified as laminar-like and turbulent-like, cannot be thought of as separate Blasius and fully-turbulent profiles, respectively. Thus, simple transition models in which the desired quantity is assumed to be an average, weighted on intermittency, of the theoretical laminar and fully turbulent values is not expected to be successful. Deviation of the flow identified as laminar-like from theoretical laminar behavior is shown to be due to recovery after the passage of a turbulent spot, while deviation of the flow identified as turbulent-like from the full-turbulent values is thought to be due to incomplete establishment of the fully-turbulent power spectral distribution. Turbulent Prandtl numbers for the transitional flow, computed from measured shear stress, turbulent heat flux and mean velocity and temperature profiles, were less than unity. For the curved-wall case with low free-stream turbulence intensity, the existence of Gortler vortices on the concave wall within both laminar and turbulent flows was established using liquid crystal visualization and spanwise velocity and temperature traverses. Transition was found to occur via a vortex breakdown mode. The vortex wavelength was quite irregular in both the laminar and turbulent flows, but the vortices were stable in time and space. The upwash was found to be more unstable, with higher levels of u' and u'v', and lower skin friction coefficients and shape factors. Turbulent Prandtl numbers, measured using a triple-wire probe, were found to be near unity for all post-transitional profiles, indicating no gross violation of Reynolds analogy. No evidence of streamwise vortices was seen in the high turbulence intensity case.

  20. Is There Asymmetry Between the Concave and Convex Pedicles in Adolescent Idiopathic Scoliosis? A CT Investigation.

    PubMed

    Davis, Colin M; Grant, Caroline A; Pearcy, Mark J; Askin, Geoffrey N; Labrom, Robert D; Izatt, Maree T; Adam, Clayton J; Little, J Paige

    2017-03-01

    Adolescent idiopathic scoliosis is a complex three-dimensional deformity of the spine characterized by deformities in the sagittal, coronal, and axial planes. Spinal fusion using pedicle screw instrumentation is a widely used method for surgical correction in severe (coronal deformity, Cobb angle > 45°) adolescent idiopathic scoliosis curves. Understanding the anatomic difference in the pedicles of patients with adolescent idiopathic scoliosis is essential to reduce the risk of neurovascular or visceral injury through pedicle screw misplacement. To use CT scans (1) to analyze pedicle anatomy in the adolescent thoracic scoliotic spine comparing concave and convex pedicles and (2) to assess the intra- and interobserver reliability of these measurements to provide critical information to spine surgeons regarding size, length, and angle of projection. Between 2007 and 2009, 27 patients with adolescent idiopathic scoliosis underwent thoracoscopic anterior correction surgery by two experienced spinal surgeons. Preoperatively, each patient underwent a CT scan as was their standard of care at that time. Twenty-two patients (mean age, 15.7 years; SD, 2.4 years; range, 11.6-22 years) (mean Cobb angle, 53°; SD, 5.3°; range, 42°-63°) were selected. Inclusion criteria were a clinical diagnosis of adolescent idiopathic scoliosis, female, and Lenke type 1 adolescent idiopathic scoliosis with the major curve confined to the thoracic spine. Using three-dimensional image analysis software, the pedicle width, inner cortical pedicle width, pedicle height, inner cortical pedicle height, pedicle length, chord length, transverse pedicle angle, and sagittal pedicle angles were measured. Randomly selected scans were remeasured by two of the authors and the reproducibility of the measurement definitions was validated through limit of agreement analysis. The concave pedicle widths were smaller compared with the convex pedicle widths at T7, T8, and T9 by 37% (3.44 mm ± 1.16 mm vs 4

  1. Use of concave mirrors and a single camera to acquire full surface information of randomly oriented apples

    USDA-ARS?s Scientific Manuscript database

    Using machine vision to fully inspect fruit for contamination requires imaging as much of the surface of each fruit as is possible. For apples, the concave nature of the stem and calyx regions present a particular problem. These regions are more likely to harbor contamination and full visualization ...

  2. Average heat-transfer characteristics of a row of circular air jets impinging on a concave surface

    NASA Technical Reports Server (NTRS)

    Livingood, J. N. B.; Gauntner, J. W.

    1972-01-01

    A study of the average heat-transfer characteristics of air jets impinging on the concave side of a right-circular semicylinder is reported. Results from existing correlating are compared with each other and with experimental heat-transfer data for a row of circular jets. Two correlations available in the literature are recommended for use in designing cooled turbine vanes and blades.

  3. Early Periimplant Tissue Healing on 1-Piece Implants With a Concave Transmucosal Design: A Histomorphometric Study in Dogs.

    PubMed

    Bolle, Caroline; Gustin, Marie-Paule; Fau, Didier; Exbrayat, Patrick; Boivin, Georges; Grosgogeat, Brigitte

    2015-10-01

    The purpose of our study was to investigate the early healing phase of marginal bone and soft tissues around unloaded 1-piece implants with a concave transmucosal design, in a dog model. Twenty-four 1-piece implants with a concave transmucosal neck were inserted 1 mm subcrestally in the mandibular ridge of 8 beagle dogs. Four animals were sacrificed after 3 and 12 weeks of healing. Histomorphometric analysis was performed to measure the height of the periimplant tissues. The overall height of the periimplant mucosa was, respectively, 2.67 and 2.52 mm, after 3 and 12 weeks. In the connective tissue, a soft tissue O-ring seal was observed in the healing area provided by the transmucosal concavity, after 12 weeks. The location of the first bone-to-implant contact facing the implant shoulder was 0.00 and +0.18 mm, respectively, after 3 and 12 weeks of healing. Some bone apposition occurred on the implant shoulder during the healing. Within the limits of the present study, a concave transmucosal design in 1-piece implants was associated with a short vertical value of biological width and promoted a mechanical interlocking of the implant body at the connective tissue and marginal bone levels.

  4. Universal tectonic dichotomy of small celestial bodies expressed in their common convexo-concave shapes

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2008-09-01

    The wave planetology [1, 2, 3 & others] declares in its first theorem that all celestial bodies are dichotomous. This is a result of a warping action of the fundamental wave (wave 1 long 2πR where R is a body radius) that appears in any body due to its movement in non-round (elliptical, parabolic) keplerian orbits with periodically changing accelerations. Having a standing character and four crossing directions in rotating bodies (but all bodies rotate!) these waves inevitably press in one hemisphere and bulge out the opposite one tending to impose on a body convexo-concave shape. This shape is leveled out in larger bodies due to enhanced gravity but is clearly observed in smaller ones with diminished gravity. Still, in the larger bodies as, for an example, in Earth the tectonic dichotomy is expressed as an opposition of the subsided western Pacific hemisphere and the uplifted eastern continental hemisphere. At Mars even sharper dichotomy is in the north-south direction. Small bodies (normally less than 400-500 km across) notwithstanding their type (asteroids, comets, satellites), size and composition (stones, metals, ices) are flattened and bended by the fundamental wave. That is why all asteroids in the main asteroid belt have an oblong shape what was established rather long ago but never was properly explained. Now a number of small satellites is observed by Cassini spacecraft in the saturnian system that makes together with jovian and martian small satellites a representative group for comparisons. In the figures below are shown asteroids, satellites and a comet arranged in a row of increasing sizes. They all are flattened except the largest in the row Enceladus (505 km) and bended tending to acquire a convexo-concave shape. Asteroids: Itokawa (0.5 km long), Eros (33 km, PIA03111). Satellites: Calypso (22 km, PIA07633), Atlas (32 km, PIA08233), Prometheus (102 km, PIA08192), Hyperion (350 km, PIA06645), Enceladus (505 km, PIA08258, comet-like behaviour). Comet

  5. Uniform Magnetic Field Between Face-to-Face HTS Bulk Magnets Combining Concave and Convex Magnetic Field Distributions

    NASA Astrophysics Data System (ADS)

    Oka, T.; Takahashi, Y.; Yaginuma, S.; Ogawa, J.; Fukui, S.; Sato, T.; Yokoyama, K.; Nakamura, T.

    The authors have been attempting to obtain the uniform magnetic field distribution in the space between the face-to-face HTS bulk magnets. The magnetic poles containing the HTS bulk magnets are usually characterized as non-uniform magnetic field distribution. Since the distributions show the conical or convex shapes, it is difficult to obtain the uniform magnetic field spaces even when the magnetic poles would be placed face-to-face. The authors have modified the shape of the distribution of one-side magnetic pole by attaching an iron plate on the surface, and formed the concave magnetic field distribution on the pole surface. The steep concave or convex distributions at each pole surface change to be flat with increasing distance from the pole surface. After the experimental result recording the best uniformity of 358 ppm by combining the concave and convex field distributions face-to-face, we attempted to simulate the feasible performance in this configuration. In the numerical simulation, the concave field distribution modified by attaching an imaginary spiral coil on the pole surface was coupled with the original convex field. We succeeded in obtaining the best uniformity of 30 ppm at 1.1 T in 4 x 4 mm2x-y plane at 7 mm distant from the pole surface in the gap of 30 mm. This result suggests that the concave and convex magnetic field distributions compensate the field uniformity with each other with keeping the magnetic field strength in the gap, and also suggests the novel compact NMR/MRI devices in the future.

  6. Dense nuclei segmentation based on graph cut and convexity-concavity analysis.

    PubMed

    Qi, J

    2014-01-01

    With the rapid advancement of 3D confocal imaging technology, more and more 3D cellular images will be available. However, robust and automatic extraction of nuclei shape may be hindered by a highly cluttered environment, as for example, in fly eye tissues. In this paper, we present a novel and efficient nuclei segmentation algorithm based on the combination of graph cut and convex shape assumption. The main characteristic of the algorithm is that it segments nuclei foreground using a graph-cut algorithm with our proposed new initialization method and splits overlapping or touching cell nuclei by simple convexity and concavity analysis. Experimental results show that the proposed algorithm can segment complicated nuclei clumps effectively in our fluorescent fruit fly eye images. Evaluation on a public hand-labelled 2D benchmark demonstrates substantial quantitative improvement over other methods. For example, the proposed method achieves a 3.2 Hausdorff distance decrease and a 1.8 decrease in the merged nuclei error per slice.

  7. Controllable synthesis of concave cubic gold core-shell nanoparticles for plasmon-enhanced photon harvesting.

    PubMed

    Bai, Yang; Butburee, Teera; Yu, Hua; Li, Zhen; Amal, Rose; Lu, G Q Max; Wang, Lianzhou

    2015-07-01

    Well-defined core-shell nanoparticles (NPs) containing concave cubic Au cores and TiO2 shells (CA@T) were synthesized in colloidal suspension. These CA@T NPs exhibit Localized Surface Plasmon Resonance (LSPR) absorption in the NIR region, which provides a unique property for utilizing the low energy range of the solar spectrum. In order to evaluate the plasmonic enhancement effect, a variety of CA@T NPs were incorporated into working electrodes of dye-sensitized solar cells (DSSCs). By adjusting the shell thickness of CA@T NPs, the plasmonic property can be tuned to achieve maximum photovoltaic improvement. Furthermore, the DSSC cells fabricated with the CA@T NPs exhibit a remarkably plasmonic assisted conversion efficiency enhancement (23.3%), compared to that (14.8%) of the reference cells assembled with spherical Au@TiO2 core-shell (SA@T) NPs under similar conditions. Various characterizations reveal that this performance improvement is attributed to the much stronger electromagnetic field generated at the hot spots of CA@T NPs, resulting in significantly higher light harvesting and more efficient charge separation. This study also provides new insights into maximizing the plasmonic enhancement, offering great potential in other applications including light-matter interaction, photocatalytic energy conversion and new-generation solar cells. Copyright © 2014. Published by Elsevier Inc.

  8. Plasma confinement by magnetic field with convex-concave field lines

    NASA Astrophysics Data System (ADS)

    Tsventoukh, Mikhail M.; Krashevskaya, Galina V.; Prishvitsyn, Alexander S.

    2015-06-01

    It has been found that plasma confinement by the magnetic field of alternating-sign curvature with convex-concave field lines results in a strong stabilizing action against convective (flute-interchange) perturbations. For simple combinations of axisymmetric mirrors and cusps the calculations according to the kinetic stability criterion give strongly, centrally peaked stable plasma pressure profiles instead of shallow ones. For the experimental research of this effect, a compact magnetic confinement device has been modified by adding of the external current coil to fulfil the field-line curvature requirements. The critical convectively-stable plasma pressure profiles calculation in this experimental geometry and the probe measurements of the spatial plasma distribution in the new magnetic configuration of alternating-sign curvature have been performed. The experimental results give some support for a conclusion that there is an increase in the ion saturation current at the region near the minimum of the specific volume min ∫dl/B. This region corresponds to the average minimum in the second adiabatic invariant, and the kinetic description predicts the stable pressure profile peaking here due to reduction of charge separation by particle drift in alternating-sign curvature.

  9. Reliable single chip genotyping with semi-parametric log-concave mixtures.

    PubMed

    Rippe, Ralph C A; Meulman, Jacqueline J; Eilers, Paul H C

    2012-01-01

    The common approach to SNP genotyping is to use (model-based) clustering per individual SNP, on a set of arrays. Genotyping all SNPs on a single array is much more attractive, in terms of flexibility, stability and applicability, when developing new chips. A new semi-parametric method, named SCALA, is proposed. It is based on a mixture model using semi-parametric log-concave densities. Instead of using the raw data, the mixture is fitted on a two-dimensional histogram, thereby making computation time almost independent of the number of SNPs. Furthermore, the algorithm is effective in low-MAF situations.Comparisons between SCALA and CRLMM on HapMap genotypes show very reliable calling of single arrays. Some heterozygous genotypes from HapMap are called homozygous by SCALA and to lesser extent by CRLMM too. Furthermore, HapMap's NoCalls (NN) could be genotyped by SCALA, mostly with high probability. The software is available as R scripts from the website www.math.leidenuniv.nl/~rrippe.

  10. A proof of convergence of the concave-convex procedure using Zangwill's theory.

    PubMed

    Sriperumbudur, Bharath K; Lanckriet, Gert R G

    2012-06-01

    The concave-convex procedure (CCCP) is an iterative algorithm that solves d.c. (difference of convex functions) programs as a sequence of convex programs. In machine learning, CCCP is extensively used in many learning algorithms, including sparse support vector machines (SVMs), transductive SVMs, and sparse principal component analysis. Though CCCP is widely used in many applications, its convergence behavior has not gotten a lot of specific attention. Yuille and Rangarajan analyzed its convergence in their original paper; however, we believe the analysis is not complete. The convergence of CCCP can be derived from the convergence of the d.c. algorithm (DCA), proposed in the global optimization literature to solve general d.c. programs, whose proof relies on d.c. duality. In this note, we follow a different reasoning and show how Zangwill's global convergence theory of iterative algorithms provides a natural framework to prove the convergence of CCCP. This underlines Zangwill's theory as a powerful and general framework to deal with the convergence issues of iterative algorithms, after also being used to prove the convergence of algorithms like expectation-maximization and generalized alternating minimization. In this note, we provide a rigorous analysis of the convergence of CCCP by addressing two questions: When does CCCP find a local minimum or a stationary point of the d.c. program under consideration? and when does the sequence generated by CCCP converge? We also present an open problem on the issue of local convergence of CCCP.

  11. Frequency-independent approach to calculate physical optics radiations with the quadratic concave phase variations

    NASA Astrophysics Data System (ADS)

    Wu, Yu Mao; Teng, Si Jia

    2016-11-01

    In this work, we develop the numerical steepest descent path (NSDP) method to calculate the physical optics (PO) radiations with the quadratic concave phase variations. With the surface integral equation method, the physical optics (PO) scattered fields are formulated and further reduced to the surface integrals. The high frequency physical critical points contributions, including the stationary phase points, the boundary resonance points and the vertex points are comprehensively studied via the proposed NSDP method. The key contributions of this work are twofold. One is that together with the PO integrals taking the quadratic parabolic and hyperbolic phase terms, this work makes the NSDP theory be complete for treating the PO integrals with quadratic phase variations. Another is that, in order to illustrate the transition effect of the high frequency physical critical points, in this work, we consider and further extend the NSDP method to calculate the PO integrals with the coalescence of the high frequency critical points. Numerical results for the highly oscillatory PO integral with the coalescence of the critical points are given to verify the efficiency of the proposed NSDP method. The NSDP method could achieve the frequency independent computational workload and error controllable accuracy in all the numerical experiments, especially for the case of the coalescence of the high frequency critical points.

  12. Frequency-independent approach to calculate physical optics radiations with the quadratic concave phase variations

    SciTech Connect

    Wu, Yu Mao; Teng, Si Jia

    2016-11-01

    In this work, we develop the numerical steepest descent path (NSDP) method to calculate the physical optics (PO) radiations with the quadratic concave phase variations. With the surface integral equation method, the physical optics (PO) scattered fields are formulated and further reduced to the surface integrals. The high frequency physical critical points contributions, including the stationary phase points, the boundary resonance points and the vertex points are comprehensively studied via the proposed NSDP method. The key contributions of this work are twofold. One is that together with the PO integrals taking the quadratic parabolic and hyperbolic phase terms, this work makes the NSDP theory be complete for treating the PO integrals with quadratic phase variations. Another is that, in order to illustrate the transition effect of the high frequency physical critical points, in this work, we consider and further extend the NSDP method to calculate the PO integrals with the coalescence of the high frequency critical points. Numerical results for the highly oscillatory PO integral with the coalescence of the critical points are given to verify the efficiency of the proposed NSDP method. The NSDP method could achieve the frequency independent computational workload and error controllable accuracy in all the numerical experiments, especially for the case of the coalescence of the high frequency critical points.

  13. Micro-concave waveguide antenna for high photon extraction from nitrogen vacancy centers in nanodiamond

    PubMed Central

    Rajasekharan, Ranjith; Kewes, Günter; Djalalian-Assl, Amir; Ganesan, Kumaravelu; Tomljenovic-Hanic, Snjezana; McCallum, Jeffrey C.; Roberts, Ann; Benson, Oliver; Prawer, Steven

    2015-01-01

    The negatively charged nitrogen-vacancy colour center (NV− center) in nanodiamond is an excellent single photon source due to its stable photon generation in ambient conditions, optically addressable nuclear spin state, high quantum yield and its availability in nanometer sized crystals. In order to make practical devices using nanodiamond, highly efficient and directional emission of single photons in well-defined modes, either collimated into free space or waveguides are essential. This is a Herculean task as the photoluminescence of the NV centers is associated with two orthogonal dipoles arranged in a plane perpendicular to the NV defect symmetry axis. Here, we report on a micro-concave waveguide antenna design, which can effectively direct single photons from any emitter into either free space or into waveguides in a narrow cone angle with more than 80% collection efficiency irrespective of the dipole orientation. The device also enhances the spontaneous emission rate which further increases the number of photons available for collection. The waveguide antenna has potential applications in quantum cryptography, quantum computation, spectroscopy and metrology. PMID:26169682

  14. Waves and rays in plano-concave laser cavities: I. Geometric modes in the paraxial approximation

    NASA Astrophysics Data System (ADS)

    Barré, N.; Romanelli, M.; Lebental, M.; Brunel, M.

    2017-05-01

    Eigenmodes of laser cavities are studied theoretically and experimentally in two companion papers, with the aim of making connections between undulatory and geometric properties of light. In this first paper, we focus on macroscopic open-cavity lasers with localized gain. The model is based on the wave equation in the paraxial approximation; experiments are conducted with a simple diode-pumped Nd:YAG laser with a variable cavity length. After recalling fundamentals of laser beam optics, we consider plano-concave cavities with on-axis or off-axis pumping, with emphasis put on degenerate cavity lengths, where modes of different order resonate at the same frequency, and combine to form surprising transverse beam profiles. Degeneracy leads to the oscillation of so-called geometric modes whose properties can be understood, to a certain extent, also within a ray optics picture. We first provide a heuristic description of these modes, based on geometric reasoning, and then show more rigorously how to derive them analytically by building wave superpositions, within the framework of paraxial wave optics. The numerical methods, based on the Fox-Li approach, are described in detail. The experimental setup, including the imaging system, is also detailed and relatively simple to reproduce. The aim is to facilitate implementation of both the numerics and of the experiments, and to show that one can have access not only to the common higher-order modes but also to more exotic patterns.

  15. An orthogonal coordinate grid following the three-dimensional viscous flow over a concave surface

    NASA Technical Reports Server (NTRS)

    Dagenhart, J. R; Saric, W. S.

    1983-01-01

    Swept wings designed for laminar flow control exhibit both centrifugal and crossflow instabilities which produce streamwise vortices that can lead to early transition from laminar to turbulent flow in the presence of Tollmien-Schlichting waves. This paper outlines an iterative algorithm for generation of an orthogonal, curvilinear, coordinate grid following the streamlines of the three-dimensional viscous flow over a swept, concave surface. The governing equations for the metric tensor are derived from the Riemann-Christoffel tensor for an Euclidian geometry. Unit vectors along streamline, normal and binormal directions are determined. The governing equations are not solved directly, but are employed only as compatibility equations. The scale factor for the streamline coordinate is obtained by an iterative integration scheme on a 200 x 100 x 5 grid, while the other two scale factors are determined from definitions. Sample results are obtained which indicate that the compatibility equation error decreases linearly with grid step size. Grids smaller than 200 x 100 x 5 are found to be inadequate to resolve the grid curvature.

  16. An orthogonal coordinate grid following the three-dimensional viscous flow over a concave surface

    NASA Technical Reports Server (NTRS)

    Dagenhart, J. R; Saric, W. S.

    1983-01-01

    Swept wings designed for laminar flow control exhibit both centrifugal and crossflow instabilities which produce streamwise vortices that can lead to early transition from laminar to turbulent flow in the presence of Tollmien-Schlichting waves. This paper outlines an iterative algorithm for generation of an orthogonal, curvilinear, coordinate grid following the streamlines of the three-dimensional viscous flow over a swept, concave surface. The governing equations for the metric tensor are derived from the Riemann-Christoffel tensor for an Euclidian geometry. Unit vectors along streamline, normal and binormal directions are determined. The governing equations are not solved directly, but are employed only as compatibility equations. The scale factor for the streamline coordinate is obtained by an iterative integration scheme on a 200 x 100 x 5 grid, while the other two scale factors are determined from definitions. Sample results are obtained which indicate that the compatibility equation error decreases linearly with grid step size. Grids smaller than 200 x 100 x 5 are found to be inadequate to resolve the grid curvature.

  17. Automatic choroid cells segmentation and counting based on approximate convexity and concavity of chain code in fluorescence microscopic image

    NASA Astrophysics Data System (ADS)

    Lu, Weihua; Chen, Xinjian; Zhu, Weifang; Yang, Lei; Cao, Zhaoyuan; Chen, Haoyu

    2015-03-01

    In this paper, we proposed a method based on the Freeman chain code to segment and count rhesus choroid-retinal vascular endothelial cells (RF/6A) automatically for fluorescence microscopy images. The proposed method consists of four main steps. First, a threshold filter and morphological transform were applied to reduce the noise. Second, the boundary information was used to generate the Freeman chain codes. Third, the concave points were found based on the relationship between the difference of the chain code and the curvature. Finally, cells segmentation and counting were completed based on the characteristics of the number of the concave points, the area and shape of the cells. The proposed method was tested on 100 fluorescence microscopic cell images, and the average true positive rate (TPR) is 98.13% and the average false positive rate (FPR) is 4.47%, respectively. The preliminary results showed the feasibility and efficiency of the proposed method.

  18. Analysis of mode stability in a concave mirror vertical-cavity surface-emitting laser with an oxide aperture.

    PubMed

    Ju, Young-Gu

    2005-05-16

    We applied the Fox-Li resonator theory to analyze the mode stability of concave mirror surface-emitting lasers. The numerical modeling incorporates the oxide aperture in the simple classical cavity by adding a non-uniform phase shifting layer to the flat mirror side. The calculation shows that there is a modal loss difference between the fundamental mode and the competing modes. The amount of loss difference depends upon cavity length and the thickness of the oxide aperture. In addition to loss difference, modal gain difference plays a key role in discriminating between the fundamental mode and the higher order transverse modes. The modal gain difference heavily depends upon the size of the oxide aperture and the field intensity distribution. To summarize, the geometry of the concave cavity affects the mode profile and the unique field profile of each transverse mode makes a difference in both modal loss and gain. Finally, this leads to a side-mode suppression.

  19. Development of twin-illumination and subtraction technique for detection of concave and convex defects on steel surfaces

    NASA Astrophysics Data System (ADS)

    Ono, Hiroaki; Ogawa, Akihiro; Yamasaki, Takahiro; Koshihara, Takahiro; Kodama, Toshifumi; Iizuka, Yukinori; Oshige, Takahiko

    2016-09-01

    Optical surface inspection of steel mill products such as pipes, plates and slabs usually has the problem of overdetection, which is caused by signals from harmless parts such as scale and surface texture. The authors propose a new inspection technique based on the experience that most harmful defects on these products have a concave or convex shape, whereas most harmless parts that might be overdetected have flat shapes. The proposed technique is called the `twin-illumination and subtraction technique'. In this technique, firstly, two images of the target area on a steel surface illuminated from the two sides are captured, respectively. A subtraction image is then calculated from these images. Comparing the images illuminated from the different sides, the images from concave or convex defects look different due to their different shadows, while images from harmless flat parts look the same because illumination does not cause any shadow. As a result, two images with the same appearances from a harmless part are canceled by subtraction, and two images with different appearances from a concave or convex defect remain even after subtraction. Finally, it is possible to detect only concave or convex defects without overdetecting flat patterns. In this manuscript, first, we explain the proposed technique and confirmation experiments in the laboratory. We also explain a new optical inspection system based on the concept described above and its application to moving hot pipes in a steel manufacturing plant to prove the effectiveness of the technique. We concluded that the inspection system has sufficient performance for use as a practical system.

  20. TAFII170 Interacts with the Concave Surface of TATA-Binding Protein To Inhibit Its DNA Binding Activity

    PubMed Central

    Pereira, Lloyd A.; van der Knaap, Jan A.; van den Boom, Vincent; van den Heuvel, Fiona A. J.; Timmers, H. T. Marc

    2001-01-01

    The human RNA polymerase II transcription factor B-TFIID consists of TATA-binding protein (TBP) and the TBP-associated factor (TAF) TAFII170 and can rapidly redistribute over promoter DNA. Here we report the identification of human TBP-binding regions in human TAFII170. We have defined the TBP interaction domain of TAFII170 within three amino-terminal regions: residues 2 to 137, 290 to 381, and 380 to 460. Each region contains a pair of Huntington-elongation-A subunit-Tor repeats and exhibits species-specific interactions with TBP family members. Remarkably, the altered-specificity TBP mutant (TBPAS) containing a triple mutation in the concave surface is defective for binding the TAFII170 amino-terminal region of residues 1 to 504. Furthermore, within this region the TAFII170 residues 290 to 381 can inhibit the interaction between Drosophila TAFII230 (residues 2 to 81) and TBP through competition for the concave surface of TBP. Biochemical analyses of TBP binding to the TATA box indicated that TAFII170 region 290-381 inhibits TBP-DNA complex formation. Importantly, the TBPAS mutant is less sensitive to TAFII170 inhibition. Collectively, our results support a mechanism in which TAFII170 induces high-mobility DNA binding by TBP through reversible interactions with its concave DNA binding surface. PMID:11585931

  1. GABA and GABA receptors alterations in the primary visual cortex of concave lens-induced myopic model.

    PubMed

    Zhao, Wen; Bi, Ai-Ling; Xu, Chao-Li; Ye, Xiang; Chen, Mei-Qing; Wang, Xin-Ting; Zhang, Xiao-Yan; Guo, Jun-Guo; Jiang, Wen-Jun; Zhang, Jin; Bi, Hong-Sheng

    2017-02-02

    Until recently most researches on myopia mechanisms have mainly been focused on the eye ball and few investigations were explored on the upper visual pathway, such as the visual cortex. The roles of gamma-aminobutyric acid (GABA) in the retinal and in the upper visual pathway are inter-correlated. As the retinal glutamate decarboxylase (GAD), GABA, and the mRNA levels of GABA receptors increased during the concave lens induced myopia formation, however, whether GABA alterations also occurred in the visual cortex during the concave lens induction is still unknown. In the present study, using HPLC, Enzyme-Linked Immunosorbent Assay (ELISA) and Real-Time Quantitative-PCR (RT-PCR) methods, we observed the changing trends of GABA, glutamate decarboxylase (GAD), and GABA receptors in the visual cortex of concave lens-induced myopic guinea pigs. Similar to the changing patterns of retinal GABA, the concentrations of GAD, GABA and the mRNA levels of GABA receptors in the visual cortex also increased. These results indicate that the exploration on myopia mechanisms should possibly be investigated on the whole visual pathway and the detailed significance of cortical GABA alterations needs further investigation.

  2. Etude aerodynamique d'un jet turbulent impactant une paroi concave

    NASA Astrophysics Data System (ADS)

    LeBlanc, Benoit

    Etant donne la demande croissante de temperatures elevees dans des chambres de combustion de systemes de propulsions en aerospatiale (turbomoteurs, moteur a reaction, etc.), l'interet dans le refroidissement par jets impactant s'est vu croitre. Le refroidissement des aubes de turbine permet une augmentation de temperature de combustion, ce qui se traduit en une augmentation de l'efficacite de combustion et donc une meilleure economie de carburant. Le transfert de chaleur dans les au bages est influence par les aspects aerodynamiques du refroidissement a jet, particulierement dans le cas d'ecoulements turbulents. Un manque de comprehension de l'aerodynamique a l'interieur de ces espaces confinees peut mener a des changements de transfert thermique qui sont inattendus, ce qui augmente le risque de fluage. Il est donc d'interet pour l'industrie aerospatiale et l'academie de poursuivre la recherche dans l'aerodynamique des jets turbulents impactant les parois courbes. Les jets impactant les surfaces courbes ont deja fait l'objet de nombreuses etudes. Par contre des conditions oscillatoires observees en laboratoire se sont averees difficiles a reproduire en numerique, puisque les structures d'ecoulements impactants des parois concaves sont fortement dependantes de la turbulence et des effets instationnaires. Une etude experimentale fut realisee a l'institut PPRIME a l'Universite de Poitiers afin d'observer le phenomene d'oscillation dans le jet. Une serie d'essais ont verifie les conditions d'ecoulement laminaires et turbulentes, toutefois le cout des essais experimentaux a seulement permis d'avoir un apercu du phenomene global. Une deuxieme serie d'essais fut realisee numeriquement a l'Universite de Moncton avec l'outil OpenFOAM pour des conditions d'ecoulement laminaire et bidimensionnel. Cette etude a donc comme but de poursuivre l'enquete de l'aerodynamique oscillatoire des jets impactant des parois courbes, mais pour un regime d'ecoulement transitoire, turbulent

  3. ANISOTROPY OF X-RAY BURSTS FROM NEUTRON STARS WITH CONCAVE ACCRETION DISKS

    SciTech Connect

    He, C.-C.; Keek, L.

    2016-03-01

    Emission from neutron stars and accretion disks in low-mass X-ray binaries is anisotropic. The non-spherical shape of the disk as well as blocking of the neutron star by the disk make the observed flux dependent on the inclination angle of the disk with respect to the line of sight. This is of importance for the interpretation of thermonuclear X-ray bursts from neutron stars. Because part of the X-ray burst is reflected off the disk, the observed burst flux depends on the anisotropies for both direct emission from the neutron star and reflection off the disk. This influences measurements of source distance, mass accretion rate, and constraints on the neutron star’s equation of state. Previous predictions of the anisotropy factors assumed a geometrically flat disk. Detailed observations of two so-called superbursts allowed for the direct and the reflected burst fluxes to each be measured separately. The reflection fraction was much higher than what the anisotropies of a flat disk can account for. We create numerical models to calculate the anisotropy factors for different disk shapes, including concave disks. We present the anisotropy factors of the direct and reflected burst fluxes separately, as well as the anisotropy of the persistent flux. Reflection fractions substantially larger than unity are produced in the case where the inner accretion disk increases steeply in height, such that part of the star is blocked from view. Such a geometry could possibly be induced by the X-ray burst if X-ray heating causes the inner disk to puff up.

  4. Effect of Concave Sound Reflecting Surfaces on Speech Intelligibility and Articulation Index.

    NASA Astrophysics Data System (ADS)

    Khaiyat, Sami Abdulrahman

    Three different methods are used to assess speech intelligibility in spaces with and without concave sound reflecting surfaces: calculated articulation index (AI), measured rapid speech transmission index (RASTI), and modified rhyme tests (MRT) with occupants. Factors such as the room size, size of curvature, the speaker's position, and the background noise level are considered in the two on -site testing methods. The MRT results show unexpectedly significant deviation from results obtained through the other methods such that they are de-emphasized in all discussions. Results from rooms without curvatures show no significant differences between the AI and RASTI values; whereas, these differences are significant when rooms with curvatures are considered. A modification factor to be subtracted from calculated AI values to account for erosional effects of the curved surfaces is developed according to further analysis of the differences between the AI and RASTI values. The magnitude of the modification factors depends on all the above factors as well as the location of the listeners within the room. There are no clear indications of any dead spots, however, the sound foci from both the 2ft. and 8ft. curvatures have caused certain group locations to have smaller modification factors than that of all other locations. The magnitude of the developed modification factors ranges between 0.01, for the 16ft. curvature in the small rooms, to 0.17, for the 8ft. curvature in the large room with NC-45 and the speaker's position is on the center. This range is of almost the same magnitude as that of the erosional corrections to calculated AI due to elevated reverberation time. This range is also of almost same magnitude as that of improvement in calculated AI due to presence of visual cues.

  5. Profile measurement of concave spherical mirror and a flat mirror using a high-speed nanoprofiler.

    PubMed

    Usuki, Koji; Kitayama, Takao; Matsumura, Hiroki; Kojima, Takuya; Uchikoshi, Junichi; Higashi, Yasuo; Endo, Katsuyoshi

    2013-05-16

    Ultraprecise aspheric mirrors that offer nanofocusing and high coherence are indispensable for developing third-generation synchrotron radiation and X-ray free-electron laser sources. In industry, the extreme ultraviolet (wavelength: 13.5 nm) lithography used for high-accuracy aspheric mirrors is a promising technology for fabricating semiconductor devices. In addition, ultraprecise mirrors with a radius of curvature of less than 10 mm are needed in many digital video instruments. We developed a new type of nanoprofiler that traces the normal vector of a mirror's surface. The principle of our measuring method is that the normal vector at each point on the surface is determined by making the incident light beam on the mirror surface and the reflected beam at that point coincide, using two sets of two pairs of goniometers and one linear stage. From the acquired normal vectors and their coordinates, the three-dimensional shape is calculated by a reconstruction algorithm. The characteristics of the measuring method are as follows: the profiler uses the straightness of laser light without using a reference surface. Surfaces of any shape can be measured, and there is no limit on the aperture size. We calibrated this nanoprofiler by considering the system error resulting from the assembly error and encoder scale error, and evaluated the performance at the nanometer scale. We suppressed the effect of random errors by maintaining the temperature in a constant-temperature room within ±0.01°C. We measured a concave spherical mirror with a radius of curvature of 400 mm and a flat mirror and compared the results with those obtained using a Fizeau interferometer. The profiles of the mirrors were consistent within the range of system errors.

  6. Profile measurement of concave spherical mirror and a flat mirror using a high-speed nanoprofiler

    PubMed Central

    2013-01-01

    Ultraprecise aspheric mirrors that offer nanofocusing and high coherence are indispensable for developing third-generation synchrotron radiation and X-ray free-electron laser sources. In industry, the extreme ultraviolet (wavelength: 13.5 nm) lithography used for high-accuracy aspheric mirrors is a promising technology for fabricating semiconductor devices. In addition, ultraprecise mirrors with a radius of curvature of less than 10 mm are needed in many digital video instruments. We developed a new type of nanoprofiler that traces the normal vector of a mirror's surface. The principle of our measuring method is that the normal vector at each point on the surface is determined by making the incident light beam on the mirror surface and the reflected beam at that point coincide, using two sets of two pairs of goniometers and one linear stage. From the acquired normal vectors and their coordinates, the three-dimensional shape is calculated by a reconstruction algorithm. The characteristics of the measuring method are as follows: the profiler uses the straightness of laser light without using a reference surface. Surfaces of any shape can be measured, and there is no limit on the aperture size. We calibrated this nanoprofiler by considering the system error resulting from the assembly error and encoder scale error, and evaluated the performance at the nanometer scale. We suppressed the effect of random errors by maintaining the temperature in a constant-temperature room within ±0.01°C. We measured a concave spherical mirror with a radius of curvature of 400 mm and a flat mirror and compared the results with those obtained using a Fizeau interferometer. The profiles of the mirrors were consistent within the range of system errors. PMID:23680514

  7. Loss of anterior concavity of the first sacrum can predict spinal involvement in ankylosing spondylitis.

    PubMed

    Kim, Ji Young; Lee, Seunghun; Joo, Kyung Bin; Song, Yoonah; Joo, Young Bin; Kim, Tae-Hwan

    2016-01-01

    In this study, we evaluated the frequency of squaring of the first sacrum (S1), defined as the loss of anterior concavity, in patients with ankylosing spondylitis (AS). We also determined the interobserver reliability in the assessment of S1 squaring and the relationships of S1 squaring with MRI findings and the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). To this end, we performed a retrospective study of 100 patients with AS (mean age 33.2 years; range 19-57 years) and 100 control patients (mean age 35.6 years; range 19-50 years). Four experienced radiologists independently assessed the presence of S1 squaring in the AS and control groups. The frequencies of S1 squaring as scored by the four observers were 47, 48, 46, and 42 in the AS group and 3, 6, 4, and 6 in the control group. The interobserver agreement among the four observers with respect to S1 squaring was excellent (κ value 0.80) in the AS group and fair to good (κ value 0.61) in the control group. In patients with AS, the presence of S1 squaring showed fair to good agreement with the MRI changes (κ value 0.74). Moreover, the mSASSSs of patients with versus without S1 squaring were significantly different (mean 23.9 vs 7.0, p < 0.001). In conclusion, S1 squaring is relatively common in patients with AS. Moreover, S1 squaring is closely correlated with MRI changes and significantly associated with the mSASSS. Assessment of S1 squaring could be a simple method that is potentially useful for predicting early spinal structural involvement in patients with AS.

  8. New feature of delayed luminescence: preillumination-induced concavity and convexity in delayed luminescence decay curve in the green alga Pseudokirchneriella subcapitata.

    PubMed

    Katsumata, Masakazu; Takeuchi, Ayano; Kazumura, Kimiko; Koike, Takashi

    2008-03-28

    A new method for measuring delayed luminescence (delayed fluorescence) employs preillumination and a dark waiting period before normal excitation. The preillumination results in a concavity and a convexity in the decay curve in delayed luminescence in the green alga Pseudokirchneriella subcapitata. Formation of the concavity and the convexity is not affected by excitation wavelength (680 nm and 700 nm). However, the concavity and the convexity progressively decrease as the dark waiting period increases after preillumination. The formation of the concavity and the convexity was inhibited by exposure to the electron transport inhibitors DBMIB (644 microg/L, 2.0 microM) and Antimycin A (55 microg/L, 0.1 microM). Samples exposed to DBMIB exhibited noticeable reduction in the concavity, whereas samples exposed to Antimycin A exhibited pronounced reduction in the convexity. There is a possibility that the formation and disappearance of the concavity and the convexity are due to the reduction-oxidation state of the plastoquinone pool and the cyclic electron transport. We expect this method being useful in evaluating the effects of chemicals (particularly toxic chemicals) on photosynthetic reactions, and the method may also help to resolve questions regarding the source of long delayed luminescence.

  9. Novel concave-convex electrode for colonic anastomoses by radiofrequency thermo-fusion.

    PubMed

    Zhao, Lingxi; Song, Chengli; Wang, Zhigang; Zhou, Yu; Li, Xinxiang; Zhu, Wei; Cuschieri, Alfred

    2015-07-01

    Successful vascular sealing by radiofrequency (RF)-induced tissue fusion is well established. The present study reports on a novel electrode structure design together with its experimental assessment for RF thermo-fusion of porcine colonic segments. Two types of electrode were constructed and used in the present study: one with a conventional smooth surface (S) and the other with a novel reciprocating concave-convex (CC) configuration. Finite element modeling was used to study the thermal distribution profile of the CC electrode. Ex vivo porcine colonic segments were used to create end-to-end serosa-to-serosa colonic anastomoses by applying a pulse of 160 W RF power for 20 s. Different compression pressures (S1, S2, S3) and (C1, C2, C3, C4, C5), were applied, via specially designed ring carriers, to the S and CC electrodes, respectively. Assessment was based on anastomotic burst pressures and histological appearances using light microscopy of paraffin sections. In total, 22 RF-induced circular anastomoses were performed. Similar burst pressures were observed for anastomoses created by the two types of electrodes (S, CC) performed under the same compression pressure. In contrast, significant differences were observed on histological examination of tissue anastomotic site. In particular, fusion areas between gaps of the CC electrode showed normal histological appearance, while the S electrode produced a completely flat featureless appearance. Furthermore, the CC electrode produced significantly different burst pressures depending on the applied compression pressure during thermo-fusion: compression pressures C1 vs. C4 produced circular anastomotic fusions with burst pressures of 21.9 ± 9.3 vs. 44.6 ± 8.9 mmHg, (p = 0.034); but the burst pressure beyond C4, declined significantly, with C4 vs. C5, burst pressures of 44.6 ± 8.9 vs. 24.7 ± 8.0 mmHg, (p = 0.034). The CC electrode exhibits larger and faster thermal diffusion profiles resulting in normal histological

  10. Elastomeric inverse moulding and vacuum casting process characterization for the fabrication of arrays of concave refractive microlenses

    NASA Astrophysics Data System (ADS)

    Desmet, L.; Van Overmeire, S.; Van Erps, J.; Ottevaere, H.; Debaes, C.; Thienpont, H.

    2007-01-01

    We present a complete and precise quantitative characterization of the different process steps used in an elastomeric inverse moulding and vacuum casting technique. We use the latter replication technique to fabricate concave replicas from an array of convex thermal reflow microlenses. During the inverse elastomeric moulding we obtain a secondary silicone mould of the original silicone mould in which the master component is embedded. Using vacuum casting, we are then able to cast out of the second mould several optical transparent poly-urethane arrays of concave refractive microlenses. We select ten particular representative microlenses on the original, the silicone moulds and replica sample and quantitatively characterize and statistically compare them during the various fabrication steps. For this purpose, we use several state-of-the-art and ultra-precise characterization tools such as a stereo microscope, a stylus surface profilometer, a non-contact optical profilometer, a Mach-Zehnder interferometer, a Twyman-Green interferometer and an atomic force microscope to compare various microlens parameters such as the lens height, the diameter, the paraxial focal length, the radius of curvature, the Strehl ratio, the peak-to-valley and the root-mean-square wave aberrations and the surface roughness. When appropriate, the microlens parameter under test is measured with several different measuring tools to check for consistency in the measurement data. Although none of the lens samples shows diffraction-limited performance, we prove that the obtained replicated arrays of concave microlenses exhibit sufficiently low surface roughness and sufficiently high lens quality for various imaging applications.

  11. Crystal Quality and Light Output Power of GaN-Based LEDs Grown on Concave Patterned Sapphire Substrate.

    PubMed

    Wu, YewChung Sermon; Isabel, A Panimaya Selvi; Zheng, Jian-Hsuan; Lin, Bo-Wen; Li, Jhen-Hong; Lin, Chia-Chen

    2015-04-22

    The crystal quality and light output power of GaN-based light-emitting diodes (LEDs) grown on concave patterned sapphire substrate (CPSS) were investigated. It was found that the crystal quality of GaN-based LEDs grown on CPSS improved with the decrease of the pattern space (percentage of c-plane). However, when the pattern space decreased to 0.41 μm (S0.41-GaN), the GaN crystallinity dropped. On the other hand, the light output power of GaN-based LEDs was increased with the decrease of the pattern space due to the change of the light extraction efficiency.

  12. Thermal Stability of Metal Nanocrystals: An Investigation of the Surface and Bulk Reconstructions of Pd Concave Icosahedra [On the Thermal Stability of Metal Nanocrystals: An Investigation of the Surface and Bulk Reconstructions of Pd Concave Icosahedra

    DOE PAGES

    Gilroy, Kyle D.; Elnabawy, Ahmed O.; Yang, Tung -Han; ...

    2017-04-27

    Despite the remarkable success in controlling the synthesis of metal nanocrystals, it still remains a grand challenge to stabilize and preserve the shapes or internal structures of metastable kinetic products. In this work, we address this issue by systematically investigating the surface and bulk reconstructions experienced by a Pd concave icosahedron when subjected to heating up to 600 °C in vacuum. We used in situ high-resolution transmission electron microscopy to identify the equilibration pathways of this far-from-equilibrium structure. We were able to capture key structural transformations occurring during the thermal annealing process, which were mechanistically rationalized by implementing self-consistent plane-wavemore » density functional theory (DFT) calculations. Specifically, the concave icosahedron was found to evolve into a regular icosahedron via surface reconstruction in the range of 200–400 °C, and then transform into a pseudospherical crystalline structure through bulk reconstruction when further heated to 600 °C. As a result, the mechanistic understanding may lead to the development of strategies for enhancing the thermal stability of metal nanocrystals.« less

  13. Heat transfer and fluid dynamics of concave-surface curvature. Final report, 1 January 1986-31 December 1988

    SciTech Connect

    Bradshaw, P.; Johnston, J.P.; Moffat, R.J.

    1988-04-21

    This project investigated the mechanisms responsible for the known increases in shear stress and convective heat transfer when a turbulent boundary layer flows over a concave wall compared to a similar flow over a flat wall. The effects of grid-generated Free-Stream Turbulence (FST level< or = 7.5% ) were also examined for flat and concave-wall TBL's. The work was conducted in a large scale boundary layer using low-speed water flow. Momentum thickness Re was = 1400. Surface heat-transfer rate was measured with a constant-temperature metal surface and by use of a liquid-crystal surface. Temperature profiles were obtained by miniature thermocouple probe down to y+ = 3 and all three velocity components by a 3-D, laser velocimeter down to y+ = 7. Heat transfer and wall shear stress were both found to be augmented by curvature and free-stream turbulence applied separately, but the combined effect of curvature and FST is not simply the sum of the individual effects. In the case of wall stress, the effects of curvature are much larger than FST effects once the flow develops downstream. The nature of the interaction is being investigated using a working hypothesis based on the ideas of active (Reynolds stress producing) and inactive can stimulate only a limited increase (order 25%) in wall friction coefficient. However, for the moderate levels of FST used in this study, no such saturation process exists to limit the increase in surface heat-transfer rate.

  14. Thermal Stability of Metal Nanocrystals: An Investigation of the Surface and Bulk Reconstructions of Pd Concave Icosahedra

    DOE PAGES

    Gilroy, Kyle D.; Elnabawy, Ahmed O.; Yang, Tung-Han; ...

    2017-05-02

    Despite the remarkable success in controlling the synthesis of metal nanocrystals, it still remains a grand challenge to stabilize and preserve the shapes or internal structures of metastable kinetic products. In this work, we address this issue by systematically investigating the surface and bulk reconstructions experienced by a Pd concave icosahedron when subjected to heating up to 600 °C in vacuum. We used in situ high-resolution transmission electron microscopy to identify the equilibration pathways of this far-from-equilibrium structure. We were able to capture key structural transformations occurring during the thermal annealing process, which were mechanistically rationalized by implementing self-consistent plane-wavemore » density functional theory (DFT) calculations. Specifically, the concave icosahedron was found to evolve into a regular icosahedron via surface reconstruction in the range of 200–400 °C, and then transform into a pseudospherical crystalline structure through bulk reconstruction when further heated to 600 °C. The mechanistic understanding may lead to the development of strategies for enhancing the thermal stability of metal nanocrystals.« less

  15. Restricted mobility of side chains on concave surfaces of solenoid proteins may impart heightened potential for intermolecular interactions.

    PubMed

    Ramya, L; Gautham, N; Chaloin, Laurent; Kajava, Andrey V

    2015-09-01

    Significant progress has been made in the determination of the protein structures with their number today passing over a hundred thousand structures. The next challenge is the understanding and prediction of protein-protein and protein-ligand interactions. In this work we address this problem by analyzing curved solenoid proteins. Many of these proteins are considered as "hub molecules" for their high potential to interact with many different molecules and to be a scaffold for multisubunit protein machineries. Our analysis of these structures through molecular dynamics simulations reveals that the mobility of the side-chains on the concave surfaces of the solenoids is lower than on the convex ones. This result provides an explanation to the observed preferential binding of the ligands, including small and flexible ligands, to the concave surface of the curved solenoid proteins. The relationship between the landscapes and dynamic properties of the protein surfaces can be further generalized to the other types of protein structures and eventually used in the computer algorithms, allowing prediction of protein-ligand interactions by analysis of protein surfaces.

  16. Small human sperm vacuoles observed under high magnification are pocket-like nuclear concavities linked to chromatin condensation failure.

    PubMed

    Boitrelle, F; Albert, M; Petit, J-M; Ferfouri, F; Wainer, R; Bergere, M; Bailly, M; Vialard, F; Selva, J

    2013-08-01

    Since an embryo's ability to grow to the blastocyst stage and implant can be improved by selection of a normal spermatozoon with a vacuole-free head, this study set out to determine the nature of small sperm vacuoles observed under high magnification (>×6300). For 15 infertile men with various sperm profiles, high-magnification microscopy was used to select motile, morphometrically normal spermatozoa with no vacuoles (n=450) or more than two small vacuoles (each of which occupied less than 4% of the head's area; n=450). Spermatozoa acrosome reaction status and degree of chromatin condensation were analysed. Three-dimensional deconvolution microscopy was used to accurately image the nucleus and acrosome at all depths in all spermatozoa. In all 450 spermatozoa with small vacuoles, the latter were seen to be abnormal, DNA-free nuclear concavities. Spermatozoa with small vacuoles were significantly more likely than vacuole-free spermatozoa to have noncondensed chromatin (39.8% versus 9.3%, respectively; P<0.0001). There was no significant difference between the two groups of spermatozoa in terms of acrosome reaction status. No association between chromatin condensation and acrosome reaction status was observed. Small human sperm vacuoles observed under high magnification are pocket-like nuclear concavities related to failure of chromatin condensation.

  17. A plano-concave, 1-3 piezocomposite transducer for swept-frequency calibration of ultrasound hydrophones below 2 MHz

    NASA Astrophysics Data System (ADS)

    Harris, Gerald R.; Gammell, Paul M.

    2002-11-01

    Rapid calibration of hydrophones used in biomedical ultrasound is possible with swept-frequency techniques such as time-delay spectrometry. However, the range below 2 MHz has largely been neglected because of insufficient source transducer bandwidth [P. M. Gammell and G. R. Harris, J. Acoust. Soc. Am. 106, L41-L46 (1999)]. Calibration in this range is important when recording pressure waveforms distorted by nonlinear propagation, especially for accurate measurement of the peak rarefactional pressure. Therefore, a 1-3 piezocomposite transducer designed for this range has been developed and tested (poled piezocomposite element, Smart Material Corp., Sarasota, FL; transducer assembly, UTX, Inc., Holmes, NY). The element has plane front and spherically concave back faces. The nonuniform thickness disperses the thickness resonance, and the composite structure suppresses radial-mode resonances. Also, the composite's lower acoustic impedance provides a more efficient match to water. A 4-cm-diameter transducer having maximum and minimum thicknesses of 1.5 cm and 1 mm produced a smooth pressure spectrum at an axial distance of 35 cm that varied <15 dB from 0.1-2 MHz. Compared to plano-concave, single-element designs having similar dimensions, the new transducer had equivalent transmit sensitivity, and its response was significantly more uniform, possibly due in part to decreased contributions from radial modes.

  18. Synthesis of Pd-Pt bimetallic nanocrystals with a concave structure through a bromide-induced galvanic replacement reaction.

    PubMed

    Zhang, Hui; Jin, Mingshang; Wang, Jinguo; Li, Weiyang; Camargo, Pedro H C; Kim, Moon J; Yang, Deren; Xie, Zhaoxiong; Xia, Younan

    2011-04-20

    This article describes a systematic study of the galvanic replacement reaction between PtCl(6)(2-) ions and Pd nanocrystals with different shapes, including cubes, cuboctahedrons, and octahedrons. It was found that Br(-) ions played an important role in initiating, facilitating, and directing the replacement reaction. The presence of Br(-) ions led to the selective initiation of galvanic replacement from the {100} facets of Pd nanocrystals, likely due to the preferential adsorption of Br(-) ions on this crystallographic plane. The site-selective galvanic replacement resulted in the formation of Pd-Pt bimetallic nanocrystals with a concave structure owing to simultaneous dissolution of Pd atoms from the {100} facets and deposition of the resultant Pt atoms on the {111} facets. The Pd-Pt concave nanocubes with different weight percentages of Pt at 3.4, 10.4, 19.9, and 34.4 were also evaluated as electrocatalysts for the oxygen reduction reaction (ORR). Significantly, the sample with a 3.4 wt.% of Pt exhibited the largest specific electrochemical surface area and was found to be four times as active as the commercial Pt/C catalyst for the ORR in terms of equivalent Pt mass.

  19. Concave slab out board of the Tonga subduction zone caused by opposite toroidal flows under the North Fiji Basin

    NASA Astrophysics Data System (ADS)

    Martin, A. K.

    2014-05-01

    An alternative scenario is proposed for the origin of a concave NE-facing slab under the North Fiji Basin between the Tonga subduction slab and Vanuatu Arc. During rollback of the Australian Plate, Vanuatu Arc rotated clockwise, whereas Fiji Platform rotated counterclockwise from 12/10 Ma until 1.5 Ma ago. Thereafter, only Vanuatu Arc rotated until the present. During the period of opposite rotations, toroidal flows entered the mantle around the northwest slab edge of Vanuatu Arc and from the northeast slab edge of Fiji Platform. The latter lies close to the northern end of the Tonga slab where arc-parallel flows are shown by volcanic geochemistry and mantle anisotropy. Opposite toroidal flows with upwelling and downwelling components generate the concave form of the combined Vanuatu/Fiji Platform slab, match its extent to mapped deep seismicity, explain its position overlying the Tonga slab, provide a mechanism for high heat flow in the North Fiji Basin as well as enriched MORB and OIB basalts in the northern NFB, and obviate slab collisions invoked to produce slab curvature.

  20. Three novel polyoxoanion-supported compounds: confinement of polyoxoanions in Ni-containing rigid concave surfaces with enhanced NLO properties.

    PubMed

    Dong, Yayu; Xu, Xiao; Zhou, Guangpeng; Miao, Hao; Hu, GongHao; Xu, Yan

    2015-11-14

    Three novel polyoxoanion-supported compounds modified by conjugated organic ligand tris(2-benzimidazylmethyl)amine (NTB) and nickel ions, [Ni(NTB)(H2O)]2(H2P2Mo5O23)·9.25H2O (1), [Ni(H2O)(NTB)]2(PMoMo(V)O40)·4.5H2O (2) and [Ni(NTB)]2(Mo8O26)·9H2O (3), have been successfully synthesized under hydrothermal conditions at different pH values. The compounds 1-3 contain similar rigid concave surfaces composed of [Ni(NTB)](2+) cations, which connect with different clusters to form the first examples of metal-NTB-modified polyoxoanion-supported compounds. Transition metal-containing rigid concave surfaces successfully confine polyoxoanions in compounds 1-3. In the synthesis of the three compounds, the pH values play an important role in the formation of polyoxoanions and the stability of the compounds. Additionally, the third-order nonlinear optical properties (NLO) and electrochemical behaviors were also investigated.

  1. Nonlinear 3D Projection Printing of Concave Hydrogel Microstructures for Long-Term Multicellular Spheroid and Embryoid Body Culture

    PubMed Central

    Hribar, K.C; Finlay, D.; Ma, X.; Qu, X.; Ondeck, M. G.; Chung, P. H.; Zanella, F.; Engler, A. J.; Sheikh, F.; Vuori, K.; Chen, S.

    2015-01-01

    Long-term culture and monitoring of individual multicellular spheroids and embryoid bodies (EBs) remains a challenge for in vitro cell propogation. Here, we used a continuous 3D projection printing approach – with an important modification of nonlinear exposure — to generate concave hydrogel microstructures that permit spheroid growth and long-term maintenance, without the need for spheroid transfer. Breast cancer spheroids grown to 10 d in the concave structures showed hypoxic cores and signs of necrosis using immunofluorescent and histochemical staining, key features of the tumor microenvironment in vivo. EBs consisting of induced pluripotent stem cells (iPSCs) grown on the hydrogels demonstrated narrow size distribution and undifferentiated markers at 3 d, followed by signs of differentiation by the presence of cavities and staining of the three germ layers at 10 d. These findings demonstrate a new method for long-term (e.g. beyond spheroid formation at day 2, and with media exchange) 3D cell culture that should be able to assist in cancer spheroid studies as well as embryogenesis and patient-derived disease modeling with iPSC EBs. PMID:25900329

  2. Design and verification of an aberration-corrected free-form concave blaze grating with variable line spacing for hyperspectral imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Ko, Cheng-Hao; Wang, Bang-Ji; Tsai, Jih-Run; Wu, Yueh-Hsun; Tsai, Sheng-Yu; Lin, Shin-Fa; Hsiao, Chiu-Der

    2017-04-01

    A flat-field aberration corrected concave blaze grating for 400-1100nm is designed and fabricated. The concave grating, which has a free-form profile with blaze grating pitch and variable line spacing, is fabricated using five-axis CNC machine with nanometer machining precision. An optical system is setup to measure the focused spot size, spectral resolution and diffraction efficiency to evaluate the performance of aberration-corrected concave grating. The blaze grating reaches a diffraction efficiency of 70%. The focused vertical spot size is 50µm, which indicates a 50µm spatial resolution at the image plane. The focused horizontal spot size is 300µm, which converts to a spectral resolution of 6nm. The design methodology can be applied to an Offner type hyperspectral imager with a free-form convex grating and variable line spacing to achieve high efficiency and high spatial and high spectral resolving power.

  3. SU-E-T-379: Concave Approximations of Target Volume Dose Metrics for Intensity- Modulated Radiotherapy Treatment Planning

    SciTech Connect

    Xie, Y; Chen, Y; Wickerhauser, M; Deasy, J

    2014-06-01

    Purpose: The widely used treatment plan metric Dx (mimimum dose to the hottest x% by volume of the target volume) is simple to interpret and use, but is computationally poorly behaved (non-convex), this impedes its use in computationally efficient intensity-modulated radiotherapy (IMRT) treatment planning algorithms. We therefore searched for surrogate metrics that are concave, computationally efficient, and accurately correlated to Dx values in IMRT treatment plans. Methods: To find concave surrogates of D95—and more generally, Dx values with variable x values—we tested equations containing one or two generalized equivalent uniform dose (gEUD) functions. Fits were obtained by varying gEUD ‘a’ parameter values, as well as the linear equation coefficients. Fitting was performed using a dataset of dose-volume histograms from 498 de-identified head and neck IMRT treatment plans. Fit characteristics were tested using a crossvalidation process. Reported root-mean-square error values were averaged over the cross-validation shuffles. Results: As expected, the two-gEUD formula provided a superior fit, compared to the single-gEUD formula. The best approximation uses two gEUD terms: 16.25 x gEUD[a=0.45] – 15.30 x gEUD[a=1.75] – 0.69. The average root-mean-square error on repeated (70/30) cross validation was 0.94 Gy. In addition, a formula was found that reasonably approximates Dx for x between 80% and 96%. Conclusion: A simple concave function using two gEUD terms was found that correlates well with PTV D95s for these head and neck treatment plans. More generally, a formula was found that represents well the Dx for x values from 80% to 96%, thus providing a computationally efficient formula for use in treatment planning optimization. The formula may need to be adjusted for other institutions with different treatment planning protocols. We conclude that the strategy of replacing Dx values with gEUD-based formulas is promising.

  4. Steepness and Concavity Controls on the Expression of Reach-Scale Channel Morphology, Debris Flow Deposition, and the Spatial Distribution of Salmonids in the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    May, C. L.; Dietrich, W. E.

    2004-12-01

    Steepness and concavity indexes derived from the power function relationship between drainage area and channel slope provide a first-order control on (1) the expression of reach-scale channel morphology, (2) runout potential of debris flows, and (3) the spatial distribution of anadromous fish in the Pacific Northwest. Channels steeper than about 10% are typically dominated by the effects of periodic debris flow scour and subsequent accumulation of coarse sediment. Downstream of this area, channels with slopes between 3 to 10% represent a transition from debris flow to fluvial process dominance. In this transitional region of the network, debris flow deposits often form fill deposits that are subsequently incised by fluvial re-working that leads to the formation of step-pool sequences. Such reaches have restricted salmonid access, generally being most favorable to steelhead and cutthroat trout. The stronger the concavity of a channel profile, the shorter the length of this transitional reach. In the Oregon Coast Range, steepness and concavity values are high and the spatial extent of transitional channels is greatly restricted (typically only occurring in reaches with draining areas between 0.5 and 1.5 km2). The abrupt change in slope from steep debris flow prone channels to low-gradient pool-riffle and bedrock channels promotes debris flow deposition and fan formation at tributary junctions. In these highly concave basins, a relatively large proportion of the fluvial channel network have gradients below 3% and are accessible to salmonids, resulting in a broad spatial distribution. This broad distribution allows for a spreading of risk that may enhance a population's ability to persist during severe disturbance. In contrast, many catchments in the Klamath Mountains of northern California have high steepness values but low concavity. In this region, the portion of the network occupied by transitional reaches is greatly expanded. Step-pool channels dominate the

  5. Synthesis of Phosphorus-Centered and Chalcogen-Bridged Concave Molecules: Modulation of Bowl Geometries and Packing Structures by Changing Bridging Atoms.

    PubMed

    Yamamura, Masaki; Hasegawa, Toru; Nabeshima, Tatsuya

    2016-02-19

    A series of phosphorus-centered concave molecules having oxygen and sulfur as bridging atoms, C3v-symmetric P4 and Cs-symmetric P2 and P3, were newly synthesized. The packing diagrams of the concave molecules P1-P4 are dependent on the bridging atoms, columnar structures for P1 and P4, and zigzag structures for P2 and P3. The bowl depth becomes shallower in the order of P1, P2, P3, and P4 as the number of bridging sulfur atoms increases.

  6. Self-assembly of metallosupramolecular rhombi from chiral concave 9,9'-spirobifluorene-derived bis(pyridine) ligands.

    PubMed

    Hovorka, Rainer; Hytteballe, Sophie; Piehler, Torsten; Meyer-Eppler, Georg; Topić, Filip; Rissanen, Kari; Engeser, Marianne; Lützen, Arne

    2014-01-01

    Two new 9,9'-spirobifluorene-based bis(4-pyridines) were synthesised in enantiopure and one also in racemic form. These ligands act as concave templates and form metallosupramolecular [(dppp)2M2L2] rhombi with cis-protected [(dppp)Pd](2+) and [(dppp)Pt](2+) ions. The self-assembly process of the racemic ligand preferably occurs in a narcissistic self-recognising manner. Hence, a mixture of all three possible stereoisomers [(dppp)2M2{(R)-L}2](OTf)4, [(dppp)2M2{(S)-L}2](OTf)4, and [(dppp)2M2{(R)-L}{(S)-L}](OTf)4 was obtained in an approximate 1.5:1.5:1 ratio which corresponds to an amplification of the homochiral assemblies by a factor of approximately three as evidenced by NMR spectroscopy and mass spectrometry. The racemic homochiral assemblies could also be characterised by single crystal X-ray diffraction.

  7. Tank Tests of a Model of a Flying-boat Hull Having a Longitudinally Concave Planing Bottom

    NASA Technical Reports Server (NTRS)

    Parkinson, J B

    1935-01-01

    The NACA model 11-B, which has a longitudinally concave planing bottom forward of the step, was tested over a wide range of loading. The results of the tests are presented as curves of resistance and trimming moment plotted against speed for various trim angles and as curves of resistance coefficient at best trim angle, and trimming-moment coefficient. The characteristics of the form at the optimum trim are compared with those of NACA model 11-C which has the same form with the exception of a planing bottom longitudinally straight near the step. Photographs of the models being towed in the tank are included for a comparison of the spray patterns. At the best angles of trim in each case model 11-B has lower resistance at high speeds, a higher maximum positive trimming moment near the hump speed, and a more favorable spray pattern than of model 11-C.

  8. Unsteady aerodynamic flow field analysis of the space shuttle configuration. Part 3: Unsteady aerodynamics of bodies with concave nose geometries

    NASA Technical Reports Server (NTRS)

    Ericsson, L. E.; Reding, J. P.

    1976-01-01

    An analysis of the unsteady aerodynamics of bodies with concave nose geometries was performed. The results show that the experimentally observed pulsating flow on spiked bodies and in forward facing cavities can be described by the developed simple mathematical model of the phenomenon. Static experimental data is used as a basis for determination of the oscillatory frequency of spike-induced flow pulsations. The agreement between predicted and measured reduced frequencies is generally very good. The spiked-body mathematical model is extended to describe the pulsations observed in forward facing cavities and it is shown that not only the frequency but also the pressure time history can be described with the accuracy needed to predict the experimentally observed time average effects. This implies that it should be possible to determine analytically the impact of the flow pulsation on the structural integrity of the nozzles for the jettisoned empty SRM-shells.

  9. Self-assembly of metallosupramolecular rhombi from chiral concave 9,9’-spirobifluorene-derived bis(pyridine) ligands

    PubMed Central

    Hovorka, Rainer; Hytteballe, Sophie; Piehler, Torsten; Meyer-Eppler, Georg; Topić, Filip; Rissanen, Kari; Engeser, Marianne

    2014-01-01

    Summary Two new 9,9’-spirobifluorene-based bis(4-pyridines) were synthesised in enantiopure and one also in racemic form. These ligands act as concave templates and form metallosupramolecular [(dppp)2M2L2] rhombi with cis-protected [(dppp)Pd]2+ and [(dppp)Pt]2+ ions. The self-assembly process of the racemic ligand preferably occurs in a narcissistic self-recognising manner. Hence, a mixture of all three possible stereoisomers [(dppp)2M2{(R)-L}2](OTf)4, [(dppp)2M2{(S)-L}2](OTf)4, and [(dppp)2M2{(R)-L}{(S)-L}](OTf)4 was obtained in an approximate 1.5:1.5:1 ratio which corresponds to an amplification of the homochiral assemblies by a factor of approximately three as evidenced by NMR spectroscopy and mass spectrometry. The racemic homochiral assemblies could also be characterised by single crystal X-ray diffraction. PMID:24605163

  10. Development of a variable focal length concave mirror for on-shot thermal lens correction in rod amplifiers.

    PubMed

    Schwarz, Jens; Geissel, Matthias; Rambo, Patrick; Porter, John; Headley, Daniel; Ramsey, Marc

    2006-11-13

    An optical surface of variable concave parabolic shape and a clear aperture of 30 mm was created using two rings to deform a flat 50.8 mm diameter mirror. The deformable mirror assembly was modeled using finite element analysis software as well as analytical solutions. Measured parabolic surface deformation showed good agreement with those models. Mirror performance was quantitatively studied using an interferometer and focal lengths from hundreds of meters down to the meter scale have been achieved. In this publication, the deformable mirror has been applied to compensate on shot thermal lensing in 16 mm diameter and 25 mm diameter Nd:Phosphate glass rod amplifiers by using only a single actuator. The possibility to rapidly change focal lengths across two to three orders of magnitude has applications for remote sensing, such as laser induced breakdown spectroscopy, LIDAR, and control of laser filament formation.

  11. Development of a variable focal length concave mirror for on-shot thermal lens correction in rod amplifiers

    NASA Astrophysics Data System (ADS)

    Schwarz, Jens; Geissel, Matthias; Rambo, Patrick; Porter, John; Headley, Daniel; Ramsey, Marc

    2006-11-01

    An optical surface of variable concave parabolic shape and a clear aperture of 30 mm was created using two rings to deform a flat 50.8 mm diameter mirror. The deformable mirror assembly was modeled using finite element analysis software as well as analytical solutions. Measured parabolic surface deformation showed good agreement with those models. Mirror performance was quantitatively studied using an interferometer and focal lengths from hundreds of meters down to the meter scale have been achieved. In this publication, the deformable mirror has been applied to compensate on shot thermal lensing in 16 mm diameter and 25 mm diameter Nd:Phosphate glass rod amplifiers by using only a single actuator. The possibility to rapidly change focal lengths across two to three orders of magnitude has applications for remote sensing, such as laser induced breakdown spectroscopy, LIDAR, and control of laser filament formation.

  12. Concave microwell array-mediated three-dimensional tumor model for screening anticancer drug-loaded nanoparticles.

    PubMed

    Kang, AhRan; Seo, Hye In; Chung, Bong Geun; Lee, Sang-Hoon

    2015-07-01

    We investigated the effect of anticancer drug-loaded functional polymeric nanoparticles on drug resistance of three-dimensional (3D) breast tumor spheroids. 3D tumor models were built using concave microwells with different diameters (300-700μm) and nanoparticles were prepared using thermo-responsive poly(N-isopropylacrylamide) (PNIPAM)-co-acrylic acid (AA). Upon culturing with doxorubicin-loaded PNIPAM-co-AA nanoparticles for 96hours, the smallest tumor spheroids were extensively disrupted, resulting in a reduction in spheroid diameter. In contrast, the sizes of the largest tumor spheroids were not changed. Scanning electron microscopy revealed that the circular shape of 3D spheroids treated with doxorubicin-loaded PNIPAM-co-AA nanoparticles had collapsed severely. Cell viability assays also demonstrated that the largest tumor spheroids cultured with doxorubicin-loaded PNIPAM-co-AA nanoparticles were highly resistant to the anticancer drug. We confirmed that tight cell-cell contacts within largest tumor spheroids significantly improved the anticancer drug resistance. Therefore, this uniform-sized 3D breast tumor model could be a potentially powerful tool for anticancer drug screening applications. The battle against cancer is a big challenge. With new anti-cancer drugs being developed under the nanotechnology platform, there is a need to have a consistent and reliable testing system that mimics the in-vivo tumor scenario. The authors successfully designed a 3D tumor model using concave microwells to produce different tumor diameters. This will be of value for future drug screening. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Plasmonic enhancement of UV emission from ZnO thin films induced by Al nano-concave arrays

    NASA Astrophysics Data System (ADS)

    Norek, Małgorzata; Łuka, Grzegorz; Włodarski, Maksymilian

    2016-10-01

    Surface plasmons (SPs) supported by Al nano-concave arrays with increasing interpore distance (Dc) were used to enhance the ultraviolet light emission from ZnO thin films. Two sets of samples were prepared: in the first set the thin ZnO films were deposited directly on Al nanoconcaves (the Al/ZnO samples) and in the second set a 10 nm - Al2O3 spacer was placed between the textured Al and the ZnO films (the Al/Al2O3-ALD/ZnO samples). In the Al/ZnO samples the enhancement was limited by a nonradiative energy dissipation due to the Ohmic loss in the Al metal. However, for the ZnO layer deposited directly on Al nanopits synthesized at 150 V (Dc = 333 ± 18 nm), the largest 9-fold enhancement was obtained by achieving the best energy fit between the near band-edge (NBE) emission from ZnO and the λ(0,1) SPP resonance mode. In the Al/Al2O3-ALD/ZnO samples the amplification of the UV emission was smaller than in the Al/ZnO samples due to a big energy mismatch between the NBE emission and the λ(0,1) plasmonic mode. The results obtained in this work indicate that better tuning of the NBE - λ(0,1) SPP resonance mode coupling is possible through a proper modification of geometrical parameters in the Al/Al2O3-ALD/ZnO system such as Al nano-concave spacing and the thickness of the corresponding layer. This approach will reduce the negative influence of the non-radiative plasmonic modes and most likely will lead to further enhancement of the SP-modulated UV emission from ZnO thin films.

  14. MOF-templated synthesis of porous Co(3)O(4) concave nanocubes with high specific surface area and their gas sensing properties.

    PubMed

    Lü, Yinyun; Zhan, Wenwen; He, Yue; Wang, Yiting; Kong, Xiangjian; Kuang, Qin; Xie, Zhaoxiong; Zheng, Lansun

    2014-03-26

    Porous metal oxides nanomaterials with controlled morphology have received great attention because of their promising applications in catalysis, energy storage and conversion, gas sensing, etc. In this paper, porous Co3O4 concave nanocubes with extremely high specific surface area (120.9 m(2)·g(-1)) were synthesized simply by calcining Co-based metal-organic framework (Co-MOF, ZIF-67) templates at the optimized temperature (300 °C), and the formation mechanism of such highly porous structures as well as the influence of the calcination temperature are well explained by taking into account thermal behavior and intrinsic structural features of the Co-MOF precursors. The gas-sensing properties of the as-synthesized porous Co3O4 concave nanocubes were systematically tested towards volatile organic compounds including ethanol, acetone, toluene, and benzene. Experimental results reveal that the porous Co3O4 concave nanocubes present the highest sensitivity to ethanol with fast response/recovery time (< 10 s) and a low detection limit (at least 10 ppm). Such outstanding gas sensing performance of the porous Co3O4 concave nanocubes benefits from their high porosity, large specific surface area, and remarkable capabilities of surface-adsorbed oxygen.

  15. Ag@Au concave cuboctahedra: A unique probe for monitoring Au-catalyzed reduction and oxidation reactions by surface-enhanced Raman spectroscopy

    SciTech Connect

    Zhang, Jiawei; Winget, Sarah A.; Wu, Yiren; Su, Dong; Sun, Xiaojun; Xie, Zhao -Xiong; Qin, Dong

    2016-01-26

    In this paper, we report a facile synthesis of Ag@Au concave cuboctahedra by titrating aqueous HAuCl4 into a suspension of Ag cuboctahedra in the presence of ascorbic acid (AA), NaOH, and poly(vinylpyrrolidone) (PVP) at room temperature. Initially, the Au atoms derived from the reduction of Au3+ by AA are conformally deposited on the entire surface of a Ag cuboctahedron. Upon the formation of a complete Au shell, however, the subsequently formed Au atoms are preferentially deposited onto the Au{100} facets, resulting in the formation of a Ag@Au cuboctahedron with concave structures at the sites of {111} facets. The concave cuboctahedra embrace excellent SERS activity that is more than 70-fold stronger than that of the original Ag cuboctahedra at an excitation wavelength of 785 nm. The concave cuboctahedra also exhibit remarkable stability in the presence of an oxidant such as H2O2 because of the protection by a complete Au shell. These two unique attributes enable in-situ SERS monitoring of the reduction of 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-ATP) by NaBH4 through a 4,4'-dimercaptoazobenzene (trans-DMAB) intermediate and the subsequent oxidation of 4-ATP back to trans-DMAB upon the introduction of H2O2.

  16. Ag@Au concave cuboctahedra: A unique probe for monitoring Au-catalyzed reduction and oxidation reactions by surface-enhanced Raman spectroscopy

    DOE PAGES

    Zhang, Jiawei; Winget, Sarah A.; Wu, Yiren; ...

    2016-01-26

    In this paper, we report a facile synthesis of Ag@Au concave cuboctahedra by titrating aqueous HAuCl4 into a suspension of Ag cuboctahedra in the presence of ascorbic acid (AA), NaOH, and poly(vinylpyrrolidone) (PVP) at room temperature. Initially, the Au atoms derived from the reduction of Au3+ by AA are conformally deposited on the entire surface of a Ag cuboctahedron. Upon the formation of a complete Au shell, however, the subsequently formed Au atoms are preferentially deposited onto the Au{100} facets, resulting in the formation of a Ag@Au cuboctahedron with concave structures at the sites of {111} facets. The concave cuboctahedramore » embrace excellent SERS activity that is more than 70-fold stronger than that of the original Ag cuboctahedra at an excitation wavelength of 785 nm. The concave cuboctahedra also exhibit remarkable stability in the presence of an oxidant such as H2O2 because of the protection by a complete Au shell. These two unique attributes enable in-situ SERS monitoring of the reduction of 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-ATP) by NaBH4 through a 4,4'-dimercaptoazobenzene (trans-DMAB) intermediate and the subsequent oxidation of 4-ATP back to trans-DMAB upon the introduction of H2O2.« less

  17. Synthesis of Au@Pt bimetallic nanoparticles with concave Au nanocuboids as seeds and their enhanced electrocatalytic properties in the ethanol oxidation reaction

    NASA Astrophysics Data System (ADS)

    Tan, Lingyu; Li, Lidong; Peng, Yi; Guo, Lin

    2015-12-01

    Herein, a new type of uniform and well-structured Au@Pt bimetallic nanoparticles (BNPs) with highly active concave Au nanocuboids (NCs) as seeds was successfully synthesized by using the classic seed-mediated method. Electrochemical measurements were conducted to demonstrate their greatly enhanced catalytic performance in the ethanol oxidation reaction (EOR). It was found that the electrochemical performance for Au@Pt BNPs with the concave Au NCs as seeds, which were enclosed by {611} high-index facets, could be seven times higher than that of the Au@Pt bimetallic nanoparticles with regular spherical Au NPs as seeds. Furthermore, our findings show that the morphology and electrocatalytic activity of the Au@Pt BNPs can be tuned simply by changing the compositional ratios of the growth solution. The lower the amount of H2PtCl6 used in the growth solution, the thinner the Pt shell grew, and the more high-index facets of concave Au NCs seeds were exposed in Au@Pt BNPs, leading to higher electrochemical activity. These as-prepared concave Au@Pt BNPs will open up new strategies for improving catalytic efficiency and reducing the use of the expensive and scarce resource of platinum in the ethanol oxidation reaction, and are potentially applicable as electrochemical catalysts for direct ethanol fuel cells.

  18. Synthesis of Au@Pt bimetallic nanoparticles with concave Au nanocuboids as seeds and their enhanced electrocatalytic properties in the ethanol oxidation reaction.

    PubMed

    Tan, Lingyu; Li, Lidong; Peng, Yi; Guo, Lin

    2015-12-18

    Herein, a new type of uniform and well-structured Au@Pt bimetallic nanoparticles (BNPs) with highly active concave Au nanocuboids (NCs) as seeds was successfully synthesized by using the classic seed-mediated method. Electrochemical measurements were conducted to demonstrate their greatly enhanced catalytic performance in the ethanol oxidation reaction (EOR). It was found that the electrochemical performance for Au@Pt BNPs with the concave Au NCs as seeds, which were enclosed by {611} high-index facets, could be seven times higher than that of the Au@Pt bimetallic nanoparticles with regular spherical Au NPs as seeds. Furthermore, our findings show that the morphology and electrocatalytic activity of the Au@Pt BNPs can be tuned simply by changing the compositional ratios of the growth solution. The lower the amount of H2PtCl6 used in the growth solution, the thinner the Pt shell grew, and the more high-index facets of concave Au NCs seeds were exposed in Au@Pt BNPs, leading to higher electrochemical activity. These as-prepared concave Au@Pt BNPs will open up new strategies for improving catalytic efficiency and reducing the use of the expensive and scarce resource of platinum in the ethanol oxidation reaction, and are potentially applicable as electrochemical catalysts for direct ethanol fuel cells.

  19. Pd@Pt core-shell concave decahedra: A class of catalysts for the oxygen reduction reaction with enhanced activity and durability

    DOE PAGES

    Wang, Xue; Vera, Madeline; Chi, Miaofang; ...

    2015-11-13

    Here, we report a facile synthesis of multiply twinned Pd@Pt core shell concave decahedra by controlling the deposition of Pt on preformed Pd decahedral seeds. The Pt atoms are initially deposited on the vertices of a decahedral seed, followed by surface diffusion to other regions along the edges/ridges and then across the faces. Different from the coating of a Pd icosahedral seed, the Pt atoms prefer to stay at the vertices and edges/ridges of a decahedral seed even when the deposition is conducted at 200 degrees C, naturally generating a core shell structure covered by concave facets. The nonuniformity inmore » the Pt coating can be attributed to the presence of twin boundaries at the vertices, as well as the {100} facets and twin defects along the edges/ridges of a decahedron, effectively trapping the Pt adatoms at these high-energy sites. As compared to a commercial Pt/C catalyst, the Pd@Pt concave decahedra show substantial enhancement in both catalytic activity and durability toward the oxygen reduction reaction (ORR). For the concave decahedra with 29.6% Pt by weight, their specific (1.66 mA/cm2pt) and mass (1.60 A/mg/2pt) ORR activities are enhanced by 4.4 and 6.6 times relative to those of the Pt/C catalyst (0.36 mA/cm2pt and 0.32 A/mgpt, respectively). After 10 000 cycles of accelerated durability test, the concave decahedra still exhibit a mass activity of 0.69 A/mgpt, more than twice that of the pristine Pt/C catalyst.« less

  20. Pd@Pt core-shell concave decahedra: A class of catalysts for the oxygen reduction reaction with enhanced activity and durability

    SciTech Connect

    Wang, Xue; Vera, Madeline; Chi, Miaofang; Xia, Younan; Luo, Ming; Huang, Hongwen; Ruditskiy, Aleksey; Park, Jinho; Bao, Shixiong; Liu, Jingyue; Howe, Jane; Xie, Zhaoxiong

    2015-11-13

    Here, we report a facile synthesis of multiply twinned Pd@Pt core shell concave decahedra by controlling the deposition of Pt on preformed Pd decahedral seeds. The Pt atoms are initially deposited on the vertices of a decahedral seed, followed by surface diffusion to other regions along the edges/ridges and then across the faces. Different from the coating of a Pd icosahedral seed, the Pt atoms prefer to stay at the vertices and edges/ridges of a decahedral seed even when the deposition is conducted at 200 degrees C, naturally generating a core shell structure covered by concave facets. The nonuniformity in the Pt coating can be attributed to the presence of twin boundaries at the vertices, as well as the {100} facets and twin defects along the edges/ridges of a decahedron, effectively trapping the Pt adatoms at these high-energy sites. As compared to a commercial Pt/C catalyst, the Pd@Pt concave decahedra show substantial enhancement in both catalytic activity and durability toward the oxygen reduction reaction (ORR). For the concave decahedra with 29.6% Pt by weight, their specific (1.66 mA/cm2pt) and mass (1.60 A/mg/2pt) ORR activities are enhanced by 4.4 and 6.6 times relative to those of the Pt/C catalyst (0.36 mA/cm2pt and 0.32 A/mgpt, respectively). After 10 000 cycles of accelerated durability test, the concave decahedra still exhibit a mass activity of 0.69 A/mgpt, more than twice that of the pristine Pt/C catalyst.

  1. Pd@Pt Core-Shell Concave Decahedra: A Class of Catalysts for the Oxygen Reduction Reaction with Enhanced Activity and Durability.

    PubMed

    Wang, Xue; Vara, Madeline; Luo, Ming; Huang, Hongwen; Ruditskiy, Aleksey; Park, Jinho; Bao, Shixiong; Liu, Jingyue; Howe, Jane; Chi, Miaofang; Xie, Zhaoxiong; Xia, Younan

    2015-12-02

    We report a facile synthesis of multiply twinned Pd@Pt core-shell concave decahedra by controlling the deposition of Pt on preformed Pd decahedral seeds. The Pt atoms are initially deposited on the vertices of a decahedral seed, followed by surface diffusion to other regions along the edges/ridges and then across the faces. Different from the coating of a Pd icosahedral seed, the Pt atoms prefer to stay at the vertices and edges/ridges of a decahedral seed even when the deposition is conducted at 200 °C, naturally generating a core-shell structure covered by concave facets. The nonuniformity in the Pt coating can be attributed to the presence of twin boundaries at the vertices, as well as the {100} facets and twin defects along the edges/ridges of a decahedron, effectively trapping the Pt adatoms at these high-energy sites. As compared to a commercial Pt/C catalyst, the Pd@Pt concave decahedra show substantial enhancement in both catalytic activity and durability toward the oxygen reduction reaction (ORR). For the concave decahedra with 29.6% Pt by weight, their specific (1.66 mA/cm(2)Pt) and mass (1.60 A/mgPt) ORR activities are enhanced by 4.4 and 6.6 times relative to those of the Pt/C catalyst (0.36 mA/cm(2)Pt and 0.32 A/mgPt, respectively). After 10,000 cycles of accelerated durability test, the concave decahedra still exhibit a mass activity of 0.69 A/mgPt, more than twice that of the pristine Pt/C catalyst.

  2. Linear QoS goals of additive and concave metrics in ad hoc cognitive packet routing.

    PubMed

    Lent, Ricardo

    2006-12-01

    This paper addresses two scalability problems related to the cognitive map of packets in ad hoc cognitive packet networks and proposes a solution. Previous works have included latency as part of the routing goal of smart packets, which requires packets to collect their arrival time at each node in a path. Such a requirement resulted in a packet overhead proportional to the path length. The second problem is that the multiplicative form of path availability, which was employed to measure resources, loses accuracy in long paths. To solve these problems, new goals are proposed in this paper. These goals are linear functions of low-overhead metrics and can provide similar performance results with lower cost. One direct result shown in simulation is that smart packets driven by a linear function of path length and buffer occupancy can effectively balance the traffic of multiple flows without the large overhead that would be needed if round-trip delay was used. In addition, energy-aware routing is also studied under this scheme as well as link selection based on their expected level of security.

  3. Flat-ramp vs. convex-concave thrust geometries in a deformable hanging wall: new insights from analogue modeling experiments

    NASA Astrophysics Data System (ADS)

    Almeida, Pedro; Tomas, Ricardo; Rosas, Filipe; Duarte, Joao; Terrinha, Pedro

    2015-04-01

    Different modes of strain accommodation affecting a deformable hanging-wall in a flat-ramp-flat thrust system were previously addressed through several (sandbox) analog modeling studies, focusing on the influence of different variables, such as: a) thrust ramp dip angle and friction (Bonini et al, 2000); b) prescribed thickness of the hanging-wall (Koy and Maillot, 2007); and c) sin-thrust erosion (compensating for topographic thrust edification, e.g. Persson and Sokoutis, 2002). In the present work we reproduce the same experimental procedure to investigate the influence of two different parameters on hanging-wall deformation: 1) the geometry of the thrusting surface; and 2) the absence of a velocity discontinuity (VD) that is always present in previous similar analogue modeling studies. Considering the first variable we use two end member ramp geometries, flat-ramp-flat and convex-concave, to understand the control exerted by the abrupt ramp edges in the hanging-wall stress-strain distribution, comparing the obtain results with the situation in which such edge singularities are absent (convex-concave thrust ramp). Considering the second investigated parameter, our motivation was the recognition that the VD found in the different analogue modeling settings simply does not exist in nature, despite the fact that it has a major influence on strain accommodation in the deformable hanging-wall. We thus eliminate such apparatus artifact from our models and compare the obtained results with the previous ones. Our preliminary results suggest that both investigated variables play a non-negligible role on the structural style characterizing the hanging-wall deformation of convergent tectonic settings were such thrust-ramp systems were recognized. Acknowledgments This work was sponsored by the Fundação para a Ciência e a Tecnologia (FCT) through project MODELINK EXPL/GEO-GEO/0714/2013. Pedro Almeida wants to thank to FCT for the Ph.D. grant (SFRH/BD/52556/2014) under the

  4. Concave gold nanocube assemblies as nanotraps for surface-enhanced Raman scattering-based detection of proteins

    NASA Astrophysics Data System (ADS)

    Matteini, Paolo; de Angelis, Marella; Ulivi, Lorenzo; Centi, Sonia; Pini, Roberto

    2015-02-01

    SERS detection of proteins is typically performed by using labeling agents with stable and high Raman scattering cross sections. This is a valuable approach for trace detection and quantification of a target protein but is unsuitable for inspecting its inherent structural and functional properties. On the other hand, direct SERS of proteins has been mainly devoted to the study of short peptides and aminoacid sequences or of prosthetic groups with intense Raman signals, which is of scarce interest for a thorough characterization of most proteins. Here we try to overcome these limitations by setting-up an effective platform for the structural SERS analysis of proteins. The platform consists of an extended bidimensional array of gold concave nanocubes (CNCs) supported on a PDMS film. CNCs are closely-packed through face-face and face-corner interactions generating a monolayered arrangement featuring well distributed nanoholes. Here the protein homogeneously experiences an E-field enhancement outward from the metal surfaces surrounding it, which causes a large number of vibrations to be contemporarily amplified. The proposed platform provides stable and detailed SERS spectra and confers rapidity and reproducibility to the analysis.SERS detection of proteins is typically performed by using labeling agents with stable and high Raman scattering cross sections. This is a valuable approach for trace detection and quantification of a target protein but is unsuitable for inspecting its inherent structural and functional properties. On the other hand, direct SERS of proteins has been mainly devoted to the study of short peptides and aminoacid sequences or of prosthetic groups with intense Raman signals, which is of scarce interest for a thorough characterization of most proteins. Here we try to overcome these limitations by setting-up an effective platform for the structural SERS analysis of proteins. The platform consists of an extended bidimensional array of gold concave

  5. A wear simulation study of nanostructured CVD diamond-on-diamond articulation involving concave/convex mating surfaces.

    PubMed

    Baker, Paul A; Thompson, Raymond G; Catledge, Shane A

    2016-03-01

    Using microwave-plasma Chemical Vapor Deposition (CVD), a 3-micron thick nanostructured-diamond (NSD) layer was deposited onto polished, convex and concave components that were machined from Ti-6Al-4V alloy. These components had the same radius of curvature, 25.4mm. Wear testing of the surfaces was performed by rotating articulation of the diamond-deposited surfaces (diamond-on-diamond) with a load of 225N for a total of 5 million cycles in bovine serum resulting in polishing of the diamond surface and formation of very shallow, linear wear grooves of less than 50nm depth. The two diamond surfaces remained adhered to the components and polished each other to an average surface roughness that was reduced by as much as a factor of 80 for the most polished region located at the center of the condyle. Imaging of the surfaces showed that the initial wearing-in phase of diamond was only beginning at the end of the 5 million cycles. Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, and surface profilometry were used to characterize the surfaces and verify that the diamond remained intact and uniform over the surface, thereby protecting the underlying metal. These wear simulation results show that diamond deposition on Ti alloy has potential application for joint replacement devices with improved longevity over existing devices made of cobalt chrome and ultra-high molecular weight polyethylene (UHMWPE).

  6. A Linear Programming Approach to Routing Control in Networks of Constrained Nonlinear Positive Systems with Concave Flow Rates

    NASA Technical Reports Server (NTRS)

    Arneson, Heather M.; Dousse, Nicholas; Langbort, Cedric

    2014-01-01

    We consider control design for positive compartmental systems in which each compartment's outflow rate is described by a concave function of the amount of material in the compartment.We address the problem of determining the routing of material between compartments to satisfy time-varying state constraints while ensuring that material reaches its intended destination over a finite time horizon. We give sufficient conditions for the existence of a time-varying state-dependent routing strategy which ensures that the closed-loop system satisfies basic network properties of positivity, conservation and interconnection while ensuring that capacity constraints are satisfied, when possible, or adjusted if a solution cannot be found. These conditions are formulated as a linear programming problem. Instances of this linear programming problem can be solved iteratively to generate a solution to the finite horizon routing problem. Results are given for the application of this control design method to an example problem. Key words: linear programming; control of networks; positive systems; controller constraints and structure.

  7. The evolution of orientational order in sheared, 2D granular media of convex and concave elongated particles

    NASA Astrophysics Data System (ADS)

    Marschall, Theodore; Teitel, Stephen

    We simulate granular media consisting of elongated grains in two dimensions with a uniform background shear. We study the orientational distribution and rotation over a wide range of packing fractions, and find that the distribution reaches a stable steady-state under most initial conditions. The nematic director increases with the packing fraction, but the nematic order parameter exhibits non-monotonic behavior, which occurs well below jamming. We observe the evolution of the orientational distribution starting from configurations with the director out of alignment from its steady state orientation, and the evolution of highly ordered initial states. In general, the tumbling motion caused by the background shear causes such systems to reorder into the steady-state, but some dense, highly-ordered configurations maintain their order and exhibit wagging behavior. This can occur both above and below the jamming transition. These results for smooth, convex, spherocylindrical particles are contrasted with those for concave cross-like particles. This work is supported by NSF Grant DMRPD-09-1765.

  8. Establishment and experimental verification of the photoresist model considering interface slip between photoresist and concave spherical substrate

    SciTech Connect

    Yang, S. E-mail: guozhongupenn@gmail.com; Zhao, X. L.; Jiang, Y. X.; Bayanheshig, E-mail: guozhongupenn@gmail.com; Wu, N.; Jiao, Q. B.; Li, W. H.; Tan, X.; Xing, S. E-mail: guozhongupenn@gmail.com

    2015-07-15

    A thickness distribution model of photoresist spin-coating on concave spherical substrate (CSS) has been developed via both theoretical studies and experimental verification. The stress of photoresist on rotating CSS is analyzed and the boundary conditions of hydrodynamic equation are presented under the non-lubricating condition. Moreover, a multivariable polynomial equation of photoresist-layer thickness distribution is derived by analyzing and deducing the flow equation where the evaporation rate, substrate topography, interface slip between liquid and CSS, and the variation of rotational speed and photoresist parameters are considered in detail. Importantly, the photoresist-layer thickness at various CSS rotational speeds and liquid concentrations can be obtained according to the theoretical equation. The required photoresist viscosity and concentration parameters of different photoresist coating thickness under a certain coating speeds can be also solved through this equation. It is noted that the calculated theoretical values are well consistent with the experimental results which were measured with various CSS rotational speeds and liquid concentrations at steady state. Therefore, both our experimental results and theoretical analysis provide the guidance for photoresist dilution and pave the way for potential improvements and microfabrication applications in the future.

  9. Design for an aberration-corrected concave grating for a mid-infrared long-slit spectrometer.

    PubMed

    Onaka, T; Miyata, T; Kataza, H; Okamoto, Y

    2000-04-01

    A new design for an aberration-corrected concave grating for the spectral region near 10 microm is presented. It was designed for use in the ground-based astronomical medium-resolution (lambda/Dlambda approximately 100) Mid-Infrared Camera and Spectrometer (MICS). It provides a flat focal plane for a wide spectral range (7.5-13.5 microm) with small aberrations, permitting efficient long-slit observations in the mid-infrared region. It permits a simple design of the spectrometer without collimator and camera mirrors, which is quite advantageous for cryogenic instruments. The grating has variable spacing grooves to reduce aberrations. In addition, the grating surface figure is designed to be toroidal and in the direction perpendicular to the grooves, aspherical, to suppress the aberrations further over a wide spectral range. The angle of the grooves is also varied to yield better efficiency near the blaze angle. The grating was fabricated by high-quality ultraprecision machining, which made these features possible. Test observations confirmed that the designed spectral resolution was achieved.

  10. Correction of Spherical Aberration in Grazing-Incidence X-ray Optics by Combination of Spherical-Concave Mirrors

    SciTech Connect

    Suzuki, Y.; Takeuchi, A.

    2011-09-09

    In grazing-incidence total-reflection mirror optics for x-rays, spherical aberrations and coma are the most serious aberrations for microfocusing and microimaging. High-resolution imaging is believed to be possible only when an aspherical mirror system is used. However, the spherical aberrations of a spherical-concave mirror in a grazing-incidence condition can be eliminated by sequential reflection of spherical mirrors of similar shapes. A sub-micrometer one-dimensional focusing is easily achieved by the spherical-aberration-corrected tandem-spherical mirror optics. By configuring four spherical mirrors in an analogy of the crossed mirror optics (Kirkpatrick-Baez optics), it is possible to achieve sub-micrometer focused beam size in the hard x-ray region. Preliminary experiments on x-ray microfocusing have been carried out at beamline 20XU of SPring-8, and a 0.5 {mu}mx0.4 {mu}m beam size was achieved at 8 keV.

  11. Numerical investigation of oscillatory thermocapillary flows under zero gravity in a circular liquid film with concave free surfaces

    NASA Astrophysics Data System (ADS)

    Yamamoto, T.; Takagi, Y.; Okano, Y.; Dost, S.

    2016-03-01

    NASA astronaut Pettit has conducted thermocapillary flow experiments in water films suspended in a solid ring onboard the International Space Station (ISS) in 2003 and 2011. In one of these experiments, an oscillatory thermocapillary flow was observed. The developed flow broke its symmetry along the centerline of the film. To the best of our knowledge, there are no studies on such oscillatory thermocapillary flows in thin films, and the flow-mechanism giving rise to such oscillatory flows is also not well understood. In order to shed light on the subject, we have carried out a numerical simulation study. The simulation results have shown that the water film geometry (film surface shape; being concave) is an important parameter and give rise to three oscillatory flow structures in the film, namely, a hydrothermal wave developing near the heated section, a symmetric oscillatory flow due to temperature variations, and a symmetry breaking flow due to the hydrodynamic instability along the free boundary layer (mixing layer) and the development of the hydrothermal waves. Simulation results show that the symmetry-breaking phenomenon observed in the thin film experiment on the ISS can be explained by the hydrodynamic instability and the development of hydrothermal waves.

  12. Wavefront error measurement of the concave ellipsoidal mirrors of the METIS coronagraph on ESA Solar Orbiter mission

    NASA Astrophysics Data System (ADS)

    Sandri, P.

    2017-04-01

    The paper describes the alignment technique developed for the wavefront error measurement of ellipsoidal mirrors presenting a central hole. The achievement of a good alignment with a classic setup at the finite conjugates when mirrors are uncoated cannot be based on the identification and materialization at naked eye of the retro-reflected spot by the mirror under test as the intensity of the retro-reflected spot results to be ≈1E-3 of the intensity of the injected laser beam of the interferometer. We present the technique developed for the achievement of an accurate alignment in the setup at the finite conjugate even in condition of low intensity based on the use of an autocollimator adjustable in focus position and a small polished flat surface on the rear side of the mirror. The technique for the alignment has successfully been used for the optical test of the concave ellipsoidal mirrors of the METIS coronagraph of the ESA Solar Orbiter mission. The presented method results to be advantageous in terms of precision and of time saving also when the mirrors are reflective coated and integrated into their mechanical hardware.

  13. An investigation of student understanding of the real image formed by a converging lens or concave mirror

    NASA Astrophysics Data System (ADS)

    Goldberg, Fred M.; McDermott, Lillian C.

    1987-02-01

    Student understanding of the real images produced by converging lenses and concave mirrors was investigated both before and after instruction in geometrical optics. The primary data were gathered through interviews in which undergraduates taking introductory physics were asked to perform a set of prescribed tasks based on a simple demonstration. The criterion used to assess understanding was the ability to apply appropriate concepts and principles, including ray diagrams, to predict and explain image formation by an actual lens or mirror. Performance on the tasks, especially by students who had not had college instruction in geometrical optics, suggested the presence of certain naive conceptions. Students who had just completed the study of geometrical optics in their physics courses were frequently unable to relate the concepts, principles, and ray-tracing techniques that had been taught in class to an actual physical system consisting of an object, a lens or a mirror, and a screen. Many students did not seem to understand the function of the lens, mirror, or screen, nor the uniqueness of the relationship among the components of the optical system. Difficulties in drawing and interpreting ray diagrams indicated inadequate understanding of the concept of a light ray and its graphical representation.

  14. Concave gold nanocube assemblies as nanotraps for surface-enhanced Raman scattering-based detection of proteins.

    PubMed

    Matteini, Paolo; de Angelis, Marella; Ulivi, Lorenzo; Centi, Sonia; Pini, Roberto

    2015-02-28

    SERS detection of proteins is typically performed by using labeling agents with stable and high Raman scattering cross sections. This is a valuable approach for trace detection and quantification of a target protein but is unsuitable for inspecting its inherent structural and functional properties. On the other hand, direct SERS of proteins has been mainly devoted to the study of short peptides and aminoacid sequences or of prosthetic groups with intense Raman signals, which is of scarce interest for a thorough characterization of most proteins. Here we try to overcome these limitations by setting-up an effective platform for the structural SERS analysis of proteins. The platform consists of an extended bidimensional array of gold concave nanocubes (CNCs) supported on a PDMS film. CNCs are closely-packed through face-face and face-corner interactions generating a monolayered arrangement featuring well distributed nanoholes. Here the protein homogeneously experiences an E-field enhancement outward from the metal surfaces surrounding it, which causes a large number of vibrations to be contemporarily amplified. The proposed platform provides stable and detailed SERS spectra and confers rapidity and reproducibility to the analysis.

  15. A wear simulation study of nanostructured CVD diamond-on-diamond articulation involving concave/convex mating surfaces

    PubMed Central

    Baker, Paul A.; Thompson, Raymond G.; Catledge, Shane A.

    2015-01-01

    Using microwave-plasma Chemical Vapor Deposition (CVD), a 3-micron thick nanostructured-diamond (NSD) layer was deposited onto polished, convex and concave components that were machined from Ti-6Al-4V alloy. These components had the same radius of curvature, 25.4mm. Wear testing of the surfaces was performed by rotating articulation of the diamond-deposited surfaces (diamond-on-diamond) with a load of 225N for a total of 5 million cycles in bovine serum resulting in polishing of the diamond surface and formation of very shallow, linear wear grooves of less than 50nm depth. The two diamond surfaces remained adhered to the components and polished each other to an average surface roughness that was reduced by as much as a factor of 80 for the most polished region located at the center of the condyle. Imaging of the surfaces showed that the initial wearing-in phase of diamond was only beginning at the end of the 5 million cycles. Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, and surface profilometry were used to characterize the surfaces and verify that the diamond remained intact and uniform over the surface, thereby protecting the underlying metal. These wear simulation results show that diamond deposition on Ti alloy has potential application for joint replacement devices with improved longevity over existing devices made of cobalt chrome and ultra-high molecular weight polyethylene (UHMWPE). PMID:26989457

  16. Experiments in Transitional Boundary Layers With Emphasis on High Free-Stream Disturbance Level, Surface Concave Curvature and Strong Favorable Streamwise Pressure Gradient Effects

    NASA Technical Reports Server (NTRS)

    Simon, T. W.; Volino, R. J.

    2007-01-01

    Experiments on boundary layer transition with flat, concave and convex walls and various levels of free-stream disturbance and with zero and strong streamwise acceleration have been conducted. Measurements of both fluid mechanics and heat transfer processes were taken. Examples are profiles of mean velocity and temperature; Reynolds normal and shear stresses; turbulent streamwise and cross-stream heat fluxed; turbulent Prandtl number; and streamwise variations of wall skin friction and heat transfer coefficient values. Free-stream turbulence levels were varied over the range from about 0.3 percent to about 8 percent. The effects of curvature on the onset of transition under low disturbance conditions are clear; concave curvature leads to an earlier and more rapid transition and the opposite is true for convex curvature This was previously known but little documentation of the transport processes in the flow was available

  17. Simulation of concave-convex imaging mirror system for development of a compact and achromatic full-field x-ray microscope.

    PubMed

    Yamada, Jumpei; Matsuyama, Satoshi; Sano, Yasuhisa; Yamauchi, Kazuto

    2017-02-01

    We propose the use of two pairs of concave-convex mirrors as imaging optics for the compact full-field x-ray microscope with high resolution and magnification factors. The optics consists of two pairs of hyperbolic convex and elliptical concave mirrors with the principal surface near the object, consequently enabling the focal length to be 10 times shorter than conventional advanced Kirkpatrick-Baez mirror optics. This paper describes characteristics of the optics calculated by ray-tracing and wave-optical simulators. The expected spatial resolution is approximately 40 nm with a wide field of view of more than 10 μm and a total length of about 2 m, which may lead to the possibility of laboratory-sized, achromatic, and high-resolution full-field x-ray microscopes.

  18. Hydrazine-linked convergent self-assembly of sophisticated concave polyhedrons of beta-Ni(OH)(2) and NiO from nanoplate building blocks.

    PubMed

    Zhou, Wei; Yao, Meng; Guo, Lin; Li, Yueming; Li, Jinghong; Yang, Shihe

    2009-03-04

    Intelligent self-assembly of nanobuilding blocks during the formation of Ni(OH)(2) single crystals with concave polyhedron structure was studied. The nickel hydroxide nanoplates pile up together with the aid of hydrazine molecules and grow along the [001] direction to form the brand-new geometry of concave polyhedrons. The novel nanostructure looks like a regularly twisted triangular prism wringed smoothly in the middle and could be attributed to the inherent spatial asymmetry of the nickel hydroxide crystal structure and the hydrogen bonds linked with the added hydrazine molecules. On the basis of the putative mechanism, polyhedrons with different longitudinal sizes (0.3-1 mum) were synthesized by adjusting the quantities of hydrazine. We also obtained NiO polyhedron crystals with similarly piled plates by calcinations of the Ni(OH)(2) polyhedrons. Our preliminary electrochemical experiments show that the Ni(OH)(2) polyhedrons have potential applications in electrochemical storage.

  19. Retrospective study of the bone morphology in the posterior mandibular region. Evaluation of the prevalence and the degree of lingual concavity and their possible complications

    PubMed Central

    Herranz-Aparicio, Judit; Marques, José; Almendros-Marqués, Nieves

    2016-01-01

    Background In order to choose the appropriate implant size and to prevent complications, an oral surgeon must know the size and shape of the mandible. In the posterior mandibular region, a lingual undercut is often found and could represent a difficulty hard to manage if a lingual or buccal perforation occur. A large series of computed tomography (CT) images of the mandibular first molar was evaluated and the bone morphology, the prevalence and the degree of the lingual concavity in the first molar region were studied. Material and Methods One hundred and fifty-one computed tomography (CT) examinations of patients were retrospectively evaluated to determine anatomical variations in bone morphology in the submandibular fossa region. Results A total of 151 subjects were included, consisting of 64 males (M) (42.4%) and 87 females (F) (57.6%). The under-cut type ridge was present in 64.2% of the cases. The concavity angle was 66.6 ± 8.9° (M) and 71.6 ± 8.4° (F) and the linear concavity depth 4.5 ± 2.3 mm (M) and 3.1 ± 1.7 mm (F) (p>0.05). Conclusions Mandibles with any lingual concavity present a potential increased risk of lingual cortical perforation during implant placement surgery. CT imaging allows characterizing the anatomy of the submandibular fossa and provides other important information for the preoperative assessment of the posterior mandible for dental implants placement. Key words:Anatomy, computed tomography, dental implants, intraoperative complications, mandible, panoramic radiography, radiographic examination. PMID:27694785

  20. Solution structure of histone chaperone ANP32B: interaction with core histones H3-H4 through its acidic concave domain.

    PubMed

    Tochio, Naoya; Umehara, Takashi; Munemasa, Yoshiko; Suzuki, Toru; Sato, Shin; Tsuda, Kengo; Koshiba, Seizo; Kigawa, Takanori; Nagai, Ryozo; Yokoyama, Shigeyuki

    2010-08-06

    Eukaryotic gene expression is regulated by histone deposition onto and eviction from nucleosomes, which are mediated by several chromatin-modulating factors. Among them, histone chaperones are key factors that facilitate nucleosome assembly. Acidic nuclear phosphoprotein 32B (ANP32B) belongs to the ANP32 family, which shares N-terminal leucine-rich repeats (LRRs) and a C-terminal variable anionic region. The C-terminal region functions as an inhibitor of histone acetylation, but the functional roles of the LRR domain in chromatin regulation have remained elusive. Here, we report that the LRR domain of ANP32B possesses histone chaperone activity and forms a curved structure with a parallel beta-sheet on the concave side and mostly helical elements on the convex side. Our analyses revealed that the interaction of ANP32B with the core histones H3-H4 occurs on its concave side, and both the acidic and hydrophobic residues that compose the concave surface are critical for histone binding. These results provide a structural framework for understanding the functional mechanisms of acidic histone chaperones. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  1. 2D numerical simulation of impinging jet onto the concave surface by k - w - overline{{v2 }} - f turbulence model

    NASA Astrophysics Data System (ADS)

    Seifi, Zeinab; Nazari, Mohammad Reza; Khalaji, Erfan

    2017-01-01

    In the present article, the characteristics of turbulent jet impinging onto a concave surface is studied using k - w - overline{{v2 }} - f turbulence model. Dependent parameters such as inlet Reynolds number (2960 < Re < 12,000), nozzle-plate distance (4 < H/B < 10), concavity (D/B = 30, 60) of confined and unconfined impinging jet are scrutinized to find out whether this approach would bring any privileges compared to other investigations or not. The obtained results indicate better performance in low nozzle-plate distance in comparison with those mentioned in other literatures. Furthermore, the average Nusselt number of confined impinging jet overtakes unconfined one (similar circumstances) while this trend will decline as relative concavity increases. Moreover, local heat transfer of stagnation area and wall jet goes up and down through nozzle-plate distance enhancement respectively. Finally, the effects of sinusoidal pulsed inlet profile on heat transfer of unconfined impinging jet indicate direct affiliation of amplitude and neutral impact of frequency on Nusselt number distribution.

  2. One-pot synthesis of high-index faceted AgCl nanocrystals with trapezohedral, concave hexoctahedral structures and their photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Zhang, Haibin; Lu, Yonggang; Liu, Hong; Fang, Jingzhong

    2015-07-01

    AgCl semiconductor nanocrystals (NCs) with trapezohedral (TPH) and concave hexoctahedral (HOH) structures have been successfully synthesized for the first time in high yield by a direct one-pot solvothermal method. The as-prepared TPH, concave HOH AgCl NCs with unconventional polyhedral shapes and smooth surfaces were enclosed by 24 high-index {311} facets and 48 high-index {15 5 2} facets, respectively. A specific ionic liquid poly(diallyldimethylammonium) chloride (PDDA) acted as both a Cl- ion precursor and a morphology-controlled stabilizer, which was indispensable for the formation of these high-index faceted AgCl polyhedra and the derived uniform octahedral AgCl in an appropriate concentration of hot AgNO3 and ethylene glycol (EG) solution. With high-index facets exposed, both TPH and concave HOH AgCl NCs exhibit much higher photocatalytic activity than octahedral AgCl NCs that have mainly {111} faces exposed, with lower surface areas and surface energies, for the degradation of organics under sunlight. It is expected that the use of polyhedral AgCl NCs with high-index facets is an effective approach for the design of alternative semiconductor photocatalysts with a high performance, which may find potential applications such as in photochromics and environmental management.

  3. In-cylinder flows of a motored four-stroke engine with flat-crown and slightly concave-crown pistons

    SciTech Connect

    Huang, R.F.; Yang, H.S.; Yeh, C.-N.

    2008-04-15

    The temporal and spatial evolution processes of the in-cylinder flow structures and turbulence intensities in the symmetry and offset planes of a motored four-valve, four-stroke engine during the intake and compression strokes are diagnosed by using a particle image velocimeter. Two pistons of different crown shapes (flat-crown and slightly concave-crown pistons) are studied. The inception, establishment, and evolution of the tumbling vortical flow structures during the intake and compression strokes are clearly depicted. Quantitative strengths of the rotating vortical flow motions are presented by a dimensionless parameter, the tumble ratio, which can represent the mean angular velocity of the vortices in the target plane. The turbulence intensity of the in-cylinder flow is also calculated by using the measured time-varying velocity data. The results show that the flat-crown piston induces higher bulk-averaged tumble ratio and turbulence intensity than the slightly concave-crown piston does because the tumble ratio and turbulence generated by the flat-crown piston in the offset planes during the compression stroke are particularly large. The engine with the flat-crown piston also presents larger torque and power outputs and lower hydrocarbon emission than that with the slightly concave-crown piston. This might be caused by the enhanced combustion in the engine cylinder due to the stronger tumble ratio and turbulence intensity. (author)

  4. A development of red internal mirror He-Ne lasers with near critical concave-convex stable resonators

    SciTech Connect

    Li Xianshu; Chen Yuchuan; Li Taoyu; Wang Yongni; He Yongjun; Gao Yangqiu; Cao Huiying; Deng Shousong

    1996-12-31

    Basic properties of the concave-convex stable resonator (CCSR) with cavity parameter g{sub 1}g{sub 2} near to 1 are discussed in the infinite aperture approximation. The field distributions and diffraction losses of the low order transverse modes of related resonators with finite aperture are analyzed numerically. The stability of the output power of the lasers with CCSR are studied experimentally. The authors have made a total of 120 red internal mirror He-Ne lasers with CCSR (g{sub 1}g{sub 2} {ge} 0.90) whose cavity lengths are approximately 63 cm and the effective lengths of discharge tubes are about 52 cm. Most of the lasers operate with TEM{sub 00} stably, and the highest output power is 30 mw. The laser beam waist lies outside the resonator at a distance of 1.0m from the convex mirror, and the beam divergence is 0.45mrad. For the TEM{sub 00} lasers operate normally, the misalignment angle of the resonator mirrors must be less than 10{sup {minus}5} rad. The following facts are of particular value. (1) When the resonant frequency spacing between two successive transverse modes of a CCSR {Delta}{nu} is so small that its effect on the competition among transverse modes in the lasers with the CCSR can be negligible, such a CCSR is called near critical CCSR (NCSR). It is observed that even if the round trip total loss (including the transmission loss and so on) of TEM{sub 01} is only about 0.2 round trip small signal gain of the laser, and the round trip diffraction loss of TEM{sub 00} is only about 0.001, still the laser with the NCSR operate with pure TEM{sub 00} stably. It is clear that the mode competition in a laser with NCSR is extraordinarily favorable for TEM{sub 00}. (2) While the TEM{sub 00} lasers operate normally, the center frequency of every longitudinal mode is stable, its drift per hour is less than 0.1 longitudinal mode spacing ({approx}2.4 {times} 10{sup 7} Hz). (3) The superradiant transition at 3.30 {micro}m is suppressed.

  5. Formation of palladium concave nanocrystals via auto-catalytic tip overgrowth by interplay of reduction kinetics, concentration gradient and surface diffusion

    NASA Astrophysics Data System (ADS)

    Su, Na; Chen, Xueying; Yue, Bin; He, Heyong

    2016-04-01

    A clear understanding of the growth mechanism involved in the shape-controlled synthesis of noble-metal nanocrystals with concave surfaces can provide useful information for the rational design of novel anisotropic nanostructures with controllable properties. In this paper, we conducted a systematic study of the detailed growth mechanism of the Pd arrow-headed tripods and revealed how the formation of the concave Pd nanocrystals was collectively controlled by the reduction kinetics, concentration gradient of Pd precursors, and surface diffusion of atoms. The formation of the arrow-headed tripods can be attributed to an auto-catalytic tip overgrowth process, where the Pd triangular nanoplate seeds formed under a suitably slow reduction rate can auto-catalyze the dehydrogenation of benzyl alcohol to generate hydrogen atoms [H]. The presence of [H] further dramatically accelerates the reduction of Pd(acac)2, which introduces a concentration gradient of Pd precursors in our non-stirring synthesis system and facilitates the kinetically-controlled tip overgrowth under a concentration gradient to form tripods with troughs on the arms. The final shapes of the concave nanocrystals depend on the relative rate of atom deposition and surface diffusion of atoms, which can be tuned by manipulating the reaction conditions such as the reaction temperature and the stirring conditions. This study presents a new possibility for the rational synthesis of various Pd nanostructures by manipulating the auto-catalytic process and tuning the relative rate of atom deposition and surface diffusion of atoms, which provides useful information for understanding the growth mechanism and the design of other anisotropic noble-metal nanostructures.

  6. Extrasinus zygomatic implants: three year experience from a new surgical approach for patients with pronounced buccal concavities in the edentulous maxilla.

    PubMed

    Aparicio, Carlos; Ouazzani, Wafaa; Aparicio, Arnau; Fortes, Vanessa; Muela, Rosa; Pascual, Andrés; Codesal, Maria; Barluenga, Natalia; Manresa, Carolina; Franch, Monica

    2010-03-01

    The surgical protocol for zygomatic fixtures prescribes an intrasinus approach ideally maintaining the sinus membrane intact and the implant body inside the sinus while gaining access to the zygomatic bone. In the presence of a pronounced buccal concavity, the implant head has to be placed far from the alveolar crest in a palatal direction, which results in a bulky bridge construction. The aim of this study was to report on the preliminary experiences with zygomatic implants placed with an extrasinus approach in order to have the implant head emerging at or near the top of the alveolar crest. Twenty consecutive patients with pronounced buccal concavities in the edentulous posterior maxilla were treated with 104 regular and 36 zygomatic implants as support of fixed dental bridges. Sixteen patients were treated bilaterally and four patients were treated unilaterally. The zygomatic implants were inserted by using an extrasinus surgical approach with the implant body passing from the alveolar crest through the buccal concavity into the zygomatic bone. This enabled placement of the implant head at or close to the alveolar crest. The patients were followed from 36 to 48 months after occlusal loading with a mean follow-up of 41 months. The relation of the zygomatic implants to the crest was measured and compared with a control group of 20 patients treated with conventional placement of zygomatic implants. No implants were lost during the study period. No pain, discomfort, or complications related to the extrasinus path of the zygomatic implants were recorded after the initial healing period and up to the 36th-month checkup. The zygomatic implants emerged, on average, 3.8 mm (SD 2.6) palatal to the top of the crest compared with 11.2 mm (SD 5.3) to the conventional technique. The present 3-year clinical study shows that an extrasinus approach can be utilized when placing zygomatic implants in patients with pronounced buccal concavities in the posterior maxilla. Moreover

  7. Cost goals

    NASA Technical Reports Server (NTRS)

    Hoag, J.

    1981-01-01

    Cost goal activities for the point focusing parabolic dish program are reported. Cost goals involve three tasks: (1) determination of the value of the dish systems to potential users; (2) the cost targets of the dish system are set out; (3) the value side and cost side are integrated to provide information concerning the potential size of the market for parabolic dishes. The latter two activities are emphasized.

  8. Tracking Costs

    ERIC Educational Resources Information Center

    Erickson, Paul W.

    2010-01-01

    Even though there's been a slight reprieve in energy costs, the reality is that the cost of non-renewable energy is increasing, and state education budgets are shrinking. One way to keep energy and operations costs from overshadowing education budgets is to develop a 10-year energy audit plan to eliminate waste. First, facility managers should…

  9. Tracking Costs

    ERIC Educational Resources Information Center

    Erickson, Paul W.

    2010-01-01

    Even though there's been a slight reprieve in energy costs, the reality is that the cost of non-renewable energy is increasing, and state education budgets are shrinking. One way to keep energy and operations costs from overshadowing education budgets is to develop a 10-year energy audit plan to eliminate waste. First, facility managers should…

  10. Measurement method of particle concentration and acoustic properties in suspension using a focused ultrasonic impulse radiated from a plano-concave transducer.

    PubMed

    Kobayashi, Tsutomu; Tai, Hidekazu; Kato, Suguru

    2006-12-22

    As a method to measure the concentration and property of a particle suspension, we proposed an ultrasonic measurement method using a plano-concave ultrasonic transducer. To carry out the experiment, we used a focused ultrasonic impulse with a broad frequency bandwidth radiated from the transducer, instead of utilizing continuous waves as in the conventional method. By analyzing the frequency components of the echo returned from the reflector put at the focal region of the transducer in suspension, we measured the concentration, etc., from variations of attenuation in the frequency spectrum. As specimens, we used some substances containing fine particles for which the acoustic properties or sizes are heterogeneous to each other. Specifically, the milk fat included in milk was examined in detail to characterize the best-tasting milk. In conclusion, we determined that the particle concentration and acoustic properties were easily and instantaneously measurable using the frequency spectrum obtained from pulse echoes passed through the specimen liquid, and the plano-concave transducer was advantageous in these measurements.

  11. Effects of Periodic Unsteady Wake Flow and Pressure Gradient on Boundary Layer Transition Along the Concave Surface of a Curved Plate. Part 3

    NASA Technical Reports Server (NTRS)

    Schobeiri, M. T.; Radke, R. E.

    1996-01-01

    Boundary layer transition and development on a turbomachinery blade is subjected to highly periodic unsteady turbulent flow, pressure gradient in longitudinal as well as lateral direction, and surface curvature. To study the effects of periodic unsteady wakes on the concave surface of a turbine blade, a curved plate was utilized. On the concave surface of this plate, detailed experimental investigations were carried out under zero and negative pressure gradient. The measurements were performed in an unsteady flow research facility using a rotating cascade of rods positioned upstream of the curved plate. Boundary layer measurements using a hot-wire probe were analyzed by the ensemble-averaging technique. The results presented in the temporal-spatial domain display the transition and further development of the boundary layer, specifically the ensemble-averaged velocity and turbulence intensity. As the results show, the turbulent patches generated by the wakes have different leading and trailing edge velocities and merge with the boundary layer resulting in a strong deformation and generation of a high turbulence intensity core. After the turbulent patch has totally penetrated into the boundary layer, pronounced becalmed regions were formed behind the turbulent patch and were extended far beyond the point they would occur in the corresponding undisturbed steady boundary layer.

  12. High-performance chromatofocusing using linear and concave pH gradients formed with simple buffer mixtures. II. Separation of proteins.

    PubMed

    Kang, X; Bates, R C; Frey, D D

    2000-08-18

    The separation of proteins using high-performance chromatofocusing with linear or concave pH gradients formed using simple mixtures of buffering species in the elution buffer is investigated experimentally. The separation achieved is comparable to that using polyampholyte elution buffers with these types of systems. More specifically, protein band widths at one half of the band height in the range between 0.1 and 0.025 pH units were observed, and good resolution was achieved of protein variants differing by a single amino acid residue in separation times of 30 min or less. An especially useful elution buffer is investigated that contains only four buffering species and that produces a linear pH gradient in the range between pH 9.5 and 6.0 when used together with a particular high-performance column packing made specifically for chromatofocusing. This elution buffer and column packing combination is evaluated by using it for the chromatofocusing of equine myoglobin and human hemoglobin variants. Additional applications are described in which a polyethyleneimine derivatized silica column packing and a pH gradient that is concave in shape are used for the separation of proteins in an E. coli cell lysate.

  13. On the piecewise convex or concave nature of ground state energy as a function of fractional number of electrons for approximate density functionals.

    PubMed

    Li, Chen; Yang, Weitao

    2017-02-21

    We provide a rigorous proof that the Hartree Fock energy, as a function of the fractional electron number, E(N), is piecewise concave. Moreover, for semi-local density functionals, we show that the piecewise convexity of the E(N) curve, as stated in the literature, is not generally true for all fractions. By an analysis based on exchange-only local density approximation and careful examination of the E(N) curve, we find for some systems, there exists a very small concave region, corresponding to adding a small fraction of electrons to the integer system, while the remaining E(N) curve is convex. Several numerical examples are provided as verification. Although the E(N) curve is not convex everywhere in these systems, the previous conclusions on the consequence of the delocalization error in the commonly used density functional approximations, in particular, the underestimation of ionization potential, and the overestimation of electron affinity, and other related issues, remain unchanged. This suggests that instead of using the term convexity, a modified and more rigorous description for the delocalization error is that the E(N) curve lies below the straight line segment across the neighboring integer points for these approximate functionals.

  14. Constructing minimum-cost flow-dependent networks

    NASA Astrophysics Data System (ADS)

    Thomas, Doreen A.; Weng, Jia F.

    2002-09-01

    In the construction of a communication network, the length of the network is an important but not unique factor determining the cost of the network. Among many possible network models, Gilbert proposed a flow-dependent model in which flow demands are assigned between each pair of points in a given point set A, and the cost per unit length of a link in the network is a function of the flow through the link. In this paper we first investigate the properties of this Gilbert model: the concavity of the cost function, decomposition, local minimality, the number of Steiner points and the maximum degree of Steiner points. Then we propose three heuristics for constructing minimum cost Gilbert networks. Two of them come from the fact that generally a minimum cost Gilbert network stands between two extremes: the complete network G(A) on A and the edge-weighted Steiner minimal tree W(A) on A. The first heuristic starts with G(A) and reduces the cost by splitting angles; the second one starts with both G(A) and W(A), and reduces the cost by selecting low cost paths. As a generalisation of the second heuristic, the third heuristic constructs a new Gilbert network of less cost by hybridising known Gilbert networks. Finally we discuss some considerations in practical applications.

  15. Effect of Platform Shift/Switch and Concave Abutments on Crestal Bone Levels and Mucosal Profile following Flap and Flapless Implant Surgery.

    PubMed

    Gamborena, Inãki; Lee, Jaebum; Fiorini, Tiago; Wenzel, Brent A; Schüpbach, Peter; Wikesjö, Ulf M E; Susin, Cristiano

    2015-10-01

    Crestal remodeling/bone loss appears to be a common sequel to dental implant placement. Several hypotheses/clinical strategies have been proposed to explain/avert crestal remodeling; however, causative mechanisms remain unclear and the efficacy of these clinical approaches uncertain. The objective of the present study was to provide a histological account of crestal bone levels and mucosal profile at platform shift/switch and concave abutments following flapless and conventional flap surgery and subcrestal implant placement using a dog model. Four dental implants each were placed in the left/right mandibular posterior jaw quadrants in five adult male Hound/Labrador mongrel dogs using flap surgery with a 1 × 5 mm gap defect or using a flapless approach, both involving placement 2 mm subcrestally and platform shift/switch versus concave abutments. Block biopsies for histological/histometric analysis were collected at 8 weeks. No significant differences were observed regarding crestal bone levels, with all groups showing mean bone levels above the implant platform. Similarly, crestal bone-implant contact was not significantly different among groups. Moreover, peri-implant mucosal profiles were not statistically different among groups for buccal sites; average mucosal height reached 4.1 to 4.9 mm above the implant platform. Comparison between buccal and lingual sites showed a nonsignificant tendency toward greater crestal resorption at buccal sites, adjusting for other factors. Mean crestal bone-implant contact level approximated the implant platform for lingual sites while consistently remaining below the platform at the buccal sites. Peri-implant mucosal height was significantly higher at buccal than at lingual sites, with the epithelial attachment located a significant distance away from the implant platform at buccal sites. The surgical approaches (subcrestal implant placement by flap surgery or a flapless approach) and abutment designs (platform shift/switch or

  16. Cost in Cost-Effectiveness

    DTIC Science & Technology

    2002-07-01

    Just to make sure we’re all talking about the same thing, I will run down the steps involved in conducting a cost -effectiveness study. The problem...systems, and forecasts of the costs of developing and producing the systems. Industry works closely with the prospective buying military departments...separate from the buying military department. These estimates are now done by the OSD Cost Analysis Improvement Group, a part of the OSD Staff

  17. Troubleshooting Costs

    NASA Astrophysics Data System (ADS)

    Kornacki, Jeffrey L.

    Seventy-six million cases of foodborne disease occur each year in the United States alone. Medical and lost productivity costs of the most common pathogens are estimated to be 5.6-9.4 billion. Product recalls, whether from foodborne illness or spoilage, result in added costs to manufacturers in a variety of ways. These may include expenses associated with lawsuits from real or allegedly stricken individuals and lawsuits from shorted customers. Other costs include those associated with efforts involved in finding the source of the contamination and eliminating it and include time when lines are shut down and therefore non-productive, additional non-routine testing, consultant fees, time and personnel required to overhaul the entire food safety system, lost market share to competitors, and the cost associated with redesign of the factory and redesign or acquisition of more hygienic equipment. The cost associated with an effective quality assurance plan is well worth the effort to prevent the situations described.

  18. Focused, phased-array plane piston and spherically-shaped concave piston transducers: comparison for the same aperture and focal point.

    PubMed

    Warriner, Renée K; Cobbold, Richard S C

    2012-04-01

    It has sometimes been assumed that the phased-array plane piston transducer and the spherically-shaped concave piston transducer are equivalent structures when both have the same aperture and focal point. This assumption has not been previously examined, nor has an expression for the on-axis impulse response of the focused, phased-array plane piston transducer been derived. It is shown in this paper how such an expression can be obtained. Comparisons of the impulse response for both structures show similarities, as well as some differences that could be significant as the observation point approaches the focal point. Comparisons are also performed for wide-band pulses close to the focus as well as for sinusoidal excitation. A physical explanation for the cause of the impulse response discrepancy is shown to be due to the nature of the piston focusing delay and its effect on the Rayleigh integral.

  19. High-performance chromatofocusing using linear and concave pH gradients formed with simple buffer mixtures. I. Effect of buffer composition on the gradient shape.

    PubMed

    Bates, R C; Kang, X; Frey, D D

    2000-08-18

    Numerical calculations together with simplified analytical relations based on local equilibrium theory are used to determine the factors which govern the shape of the gradient formed during chromatofocusing when simple mixtures of buffering species are employed to produce linear or concave pH gradients. The numerical and analytical development is also used to determine the relation between the gradient shape and the buffering capacities of the adsorbed and liquid phases. Experiments which verify the theoretical methods are described where internally generated, retained pH gradients of various shapes are formed using high-performance chromatography columns. The resulting experimental and theoretical basis can be employed as means for the selection of the buffer composition for use in chromatofocusing.

  20. Exploiting concave-convex linear resonators to design end-pumped solid-state lasers with flexible cavity lengths: Application for exploring the self-mode-locked operation.

    PubMed

    Tuan, P H; Chang, C C; Lee, C Y; Cho, C Y; Liang, H C; Chen, Y F

    2016-11-14

    The characteristics of a convex-concave linear resonator under the thermal lensing effect are theoretically analyzed to find an analytical model for designing end-pumped solid-state lasers with flexible cavity lengths. By exploiting the design model, the power scaling for continuous-wave operation under strong thermal lensing can be easily achieved in the proposed resonator with different cavity lengths. Furthermore, the proposed resonator is applied to explore the exclusive influence of cavity length on the self-mode-locked (SML) operation. It is discovered that the lasing longitudinal modes will split into multiple groups in optical spectrum to lead to a multi-pulse mode-locked temporal state when the cavity length increases. Finally, a theoretical model is derived to reconstruct the experimental results of SML operation to deduce a simple relationship between the group number of lasing modes and the cavity length.

  1. Preparation of concave magnetoplasmonic core-shell supraparticles of gold-coated iron oxide via ion-reducible layer-by-layer method for surface enhanced Raman scattering.

    PubMed

    Lee, Dong Kyu; Song, Younseong; Tran, Van Tan; Kim, Jeonghyo; Park, Enoch Y; Lee, Jaebeom

    2017-03-23

    Preparation of suprastructure assemblies with unique colloidal and optical properties remains challenging. Non-uniform covering of magnetic nanoparticles (NPs) with an external inert Au shell has been attempted to protect the magnetic core against oxidation as well as to produce multifunctional supraparticles (SPs) possessing respective optical and magnetic properties. In this study, a concave Au NP coating was deposited on magnetic nanoparticles (MNPs) with precise control of the shell thickness and roughness through a layer-by-layer (LbL) assisted ionic reduction method termed ion-reducible LbL (IR-LbL) method. Surface enhanced Raman spectra were obtained using graphene quantum dots (GQDs) on the magnetically aligned structure of the prepared core-shell SPs. It is probable that this synthesis method and the generated SPs are essential for characterizing the merge of electronics and magnetism in the nano-regime and may be applicable for further electronics, magnetic storage, and biomedical applications.

  2. 3D modelling of interaction of strongly nonlinear internal seiches with a concave lake topography and a phenomenon of the "lake monsters".

    NASA Astrophysics Data System (ADS)

    Terletska, Kateryna; Maderich, Vladimir; Brovchenko, Igor; Jung, Kyung Tae

    2013-04-01

    In the freshwater lakes in moderate latitudes stratification occurs as a result of the seasonal warming of the surface water layer. Than the intense wind surges (usually in autumn) tilt the surface and generate long basin-scale low-frequency standing internal waves (seiches). Depending on the initial interface tilt and stratification wide spectra of possible flow regimes can be observed [1]-[2].They varied from small amplitude symmetric seiches to large amplitude nonlinear waves.Nonlinearity leads to an asymmetry of internal waves and appearance of the surge or bore and further disintegration of it on a sequence of solitary waves. In present study degeneration of the strongly nonlinear internal seiches in elongated lakes with a concave "spoon-like" topography is investigated.Two different three-dimensional non-hydrostatic free-surface numerical models are used to investigate degeneration of large internal waves and its subsequent interaction with the concave lake slope. One of this model is non-hydrostatic model [3] and the other is a well-known MIT model. At first we consider idealized elongated elliptic-shape lake with the dimension of 5 km X 1 km with the maximal depth 30 m. The stratification in lake is assumed to be given in a form of the tangent function with a density difference between upper and lower layers 2 kgm-3 . It is assumed that motion in such lake is initiated by inclination of thermocline on a certain angle. Than lake adjusts to return to its original state producing internal seiches which begin interacting with a bottom topography. The process of degeneration of internal seiches in the lake with concave ends consist of chain of elementary processes: 1) steeping of long basin scale large amplitude wave, that evolve into internal surge, 2) surge interact with concave lake ends that leads the concentration of the flow and formation of down slope bottom jet along the lake axis, 3) due to cumulative effect local velocity in the jet accelerates up to

  3. Cost Control

    ERIC Educational Resources Information Center

    Foreman, Phillip

    2009-01-01

    Education administrators involved in construction initiatives unanimously agree that when it comes to change orders, less is more. Change orders have a negative rippling effect of driving up building costs and producing expensive project delays that often interfere with school operations and schedules. Some change orders are initiated by schools…

  4. Recent developments in finishing of deep concave, aspheric, and plano surfaces utilizing the UltraForm 5-axes computer controlled system

    NASA Astrophysics Data System (ADS)

    Bambrick, Scott; Bechtold, Mike; DeFisher, Scott; Mohring, David; Meisenzahl, Joe

    2009-05-01

    OptiPro Systems has developed a robust 5-axes computer controlled platform, for implementation of the sub-aperture UltraForm Finishing (UFF) process specifically focused on finishing AlON, spinel and transparent polycrystalline alumina (PCA) steep concave, convex and ogive shaped infrared domes and aspheres. Traditional manufacturing of optical components typically involves a three-stage process: grinding, lapping and polishing. The lapping and polishing stages are focused at reducing the surface roughness while preserving the integrity of the form acquired during grinding. Polishing of non spherical and irregular shapes is nearly impossible using traditional full aperture techniques. However, finishing these non-spherical and irregular shapes is possible using UltraForm Finishing. A brief description of the evolution of the UltraForm hardware and processes will be presented, with the current hardware developments. A review of the results with regard to form/figure and roughness improvements on glass, AlON and transparent PCA will be presented using a variety of grinding and finishing abrasives. Differences in the abrasive materials, some bound, and others loose in a slurry have a large impact on the process cycle time and resultant surface roughness.

  5. Welder identity, weld date, and the risk of outlet strut fracture in Björk-Shiley convexo-concave valves: the Dutch cohort study.

    PubMed

    Kallewaard, M; Algra, A; van der Graaf, Y

    1996-12-01

    To establish whether there is an association between subsequent fracture of the outlet strut and welder identity and the weld date of Björk-Shiley convexo-concave (BScc) valves. Cohort study. All Dutch BScc valve recipients (n = 2266). Documented outlet strut fracture during follow up. Weld dates were known for 97.0% of all BScc valves (n = 2534) implanted in Dutch patients (n = 2266) and welder identity was known for 52.2%. During a mean follow up of 9.4 years, 46 fractures were documented. For 60 degrees valves welded from 1981 to 1984 the fracture rate (0.22 per 100 person-years (95% CI 0.13 to 0.34)) was higher than that for valves welded before 1981 (0.04 (95% CI 0.01-0.10)). When all fracture related risk factors were taken into account, fracture rates per welder did not show any statistically significant differences. Welder identity does not contribute to the risk of strut fracture. Other factors in the production of BScc valves may explain the increased risk for valves welded from 1981 to 1984.

  6. Welder identity, weld date, and the risk of outlet strut fracture in Björk-Shiley convexo-concave valves: the Dutch cohort study.

    PubMed Central

    Kallewaard, M.; Algra, A.; van der Graaf, Y.

    1996-01-01

    OBJECTIVE: To establish whether there is an association between subsequent fracture of the outlet strut and welder identity and the weld date of Björk-Shiley convexo-concave (BScc) valves. DESIGN: Cohort study. PATIENTS: All Dutch BScc valve recipients (n = 2266). MEAN OUTCOME MEASURES: Documented outlet strut fracture during follow up. RESULTS: Weld dates were known for 97.0% of all BScc valves (n = 2534) implanted in Dutch patients (n = 2266) and welder identity was known for 52.2%. During a mean follow up of 9.4 years, 46 fractures were documented. For 60 degrees valves welded from 1981 to 1984 the fracture rate (0.22 per 100 person-years (95% CI 0.13 to 0.34)) was higher than that for valves welded before 1981 (0.04 (95% CI 0.01-0.10)). When all fracture related risk factors were taken into account, fracture rates per welder did not show any statistically significant differences. CONCLUSIONS: Welder identity does not contribute to the risk of strut fracture. Other factors in the production of BScc valves may explain the increased risk for valves welded from 1981 to 1984. PMID:9014800

  7. The Economics of NASA Mission Cost Reserves

    NASA Technical Reports Server (NTRS)

    Whitley, Sally; Shinn, Stephen

    2012-01-01

    Increases in NASA mission costs are well-noted but not well-understood, and there is little evidence that they are decreasing in frequency or amount over time. The need to control spending has led to analysis of the causes and magnitude of historical mission overruns, and many program control efforts are being implemented to attempt to prevent or mitigate the problem (NPR 7120). However, cost overruns have not abated, and while some direct causes of increased spending may be obvious (requirements creep, launch delays, directed changes, etc.), the underlying impetus to spend past the original budget may be more subtle. Gaining better insight into the causes of cost overruns will help NASA and its contracting organizations to avoid .them. This paper hypothesizes that one cause of NASA mission cost overruns is that the availability of reserves gives project team members an incentive to make decisions and behave in ways that increase costs. We theorize that the presence of reserves is a contributing factor to cost overruns because it causes organizations to use their funds less efficiently or to control spending less effectively. We draw a comparison to the insurance industry concept of moral hazard, the phenomenon that the presence of insurance causes insureds to have more frequent and higher insurance losses, and we attempt to apply actuarial techniques to quantifY the increase in the expected cost of a mission due to the availability of reserves. We create a theoretical model of reserve spending motivation by defining a variable ReserveSpending as a function of total reserves. This function has a positive slope; for every dollar of reserves available, there is a positive probability of spending it. Finally, the function should be concave down; the probability of spending each incremental dollar of reserves decreases progressively. We test the model against available NASA CADRe data by examining missions with reserve dollars initially available and testing whether

  8. Telescope costs and cost reduction

    NASA Astrophysics Data System (ADS)

    Schmidt-Kaler, Theodor; Rucks, Peter

    1997-03-01

    The prices of more than 60 telescopes of the most diverse types and sizes are analyzed according to telescope aperture. Actualized prices in 1995 were calculated taking inflation into account, as well as fluctuations in the DM exchange rate. We discuss the dependence of prices on factors like size, mass, optical system, number of construction parts (similarity laws), as well as on special technical requirements. The relationship between telescope aperture and costs shows interesting differences between the classical astronomical telescopes and the new, large telescope projects. The number of repeated construction parts and the number of realized instruments with the same design is of great importance. Cost reductions are best achieved in the conception and design phase of telescope development.

  9. Velocity of closure of Björk-Shiley Convexo-Concave mitral valves: effect of mitral annulus orientation and rate of left ventricular pressure rise.

    PubMed

    Blick, E F; Wieting, D W; Inderbitzen, R; Schreck, S; Stein, P D

    1995-07-01

    The purpose of this study was to determine analytically the hemodynamic factors that affect the closing velocity of the disc of Björk-Shiley convexo-concave (BSCC) prosthetic mitral valves. The motion of the BSCC disk was modelled by Newton's second law written in the form of a second order differential equation which expressed the instantaneous angle of the disc with respect to the valve ring as a function of the instantaneous pressure drop across the mitral valve, delta P(t), and the angle of the pressure gradient vector acting upon the disc during closure. The disc closes in response to the negative pressure drop created by the crossover of left atrial and left ventricular (LV) pressures. The rate of closure depends on the rate of development of the pressure drop across the valve, d delta P/dt, which is largely dependent upon the rate of change of left ventricular pressure during isovolumic contraction, LV dP/dt. The closure rate is also strongly dependent on the initial angle of the pressure drop vector with respect to the disc. The disc was predicted to reach its highest velocity at the moment of impact, based on the Runge-Kutta solution. Modelling suggests that a high LV dP/dt during valve closure or distorted LV geometry, causing the angle between the fully open disc and the pressure drop vector to shift, will cause the valve to have a high velocity at the moment of impact and may produce high impact loads.

  10. Parametric Cost Deployment

    NASA Technical Reports Server (NTRS)

    Dean, Edwin B.

    1995-01-01

    Parametric cost analysis is a mathematical approach to estimating cost. Parametric cost analysis uses non-cost parameters, such as quality characteristics, to estimate the cost to bring forth, sustain, and retire a product. This paper reviews parametric cost analysis and shows how it can be used within the cost deployment process.

  11. The effect of fight cost structure on fighting behaviour.

    PubMed

    Broom, Mark; Johanis, Michal; Rychtář, Jan

    2015-10-01

    A common feature of animal populations is the stealing by animals of resources such as food from other animals. This has previously been the subject of a range of modelling approaches, one of which is the so called "producer-scrounger" model. In this model a producer finds a resource that takes some time to be consumed, and some time later a (generally) conspecific scrounger discovers the producer with its resource and potentially attempts to steal it. In this paper we consider a variant of this scenario where each individual can choose to invest an amount of energy into this contest, and the level of investment of each individual determines the probability of it winning the contest, but also the additional cost it has to bear. We analyse the model for a specific set of cost functions and maximum investment levels and show how the evolutionarily stable behaviour depends upon them. In particular we see that for high levels of maximum investment, the producer keeps the resource without a fight for concave cost functions, but for convex functions the scrounger obtains the resource (albeit at some cost).

  12. A concave-patterned TiN/PECVD-Si3N4 /TiN diaphragm MEMS acoustic sensor based on a polyimide sacrificial layer

    NASA Astrophysics Data System (ADS)

    Lee, Jaewoo; Jeon, J. H.; Je, C. H.; Kim, Y.-G.; Lee, S. Q.; Yang, W. S.; Lee, J. S.; Lee, S.-G.

    2015-12-01

    In this paper, we present a concave-patterned TiN/PECVD-Si3N4 /TiN diaphragm micro-electro-mechanical system (MEMS) acoustic sensor based on a polyimide sacrificial layer. The use of the spin-coated polyimide eliminates the additional Al pad process of conventional device fabrication due to simple O2 ashing to release the sacrificial layer, simplifying the photolithography process. Also, to adjust the acoustic sensor for a bottom-ported package, its diaphragm was implemented to be placed over the back-plate. The TiN/PECVD-Si3N4/TiN multi-layer diaphragm was formed with the stress controllability of PECVD-Si3N4 from  -162 MPa to  +109 MPa. Furthermore, a parallel-plate capacitance model on the basis of an approximately linearized electric field method (ALEM) is proposed to evaluate the capacitance of two plates. The modelled capacitance showed less than 3.7% error in FEM simulation, demonstrating the validity of the proposed model. At a zero-bias voltage, the effective intrinsic and parasitic capacitances in the active area were 1.656 pF and 0.388 pF, respectively. Moreover, with a pull-in analytical model by using ALEM, the effective tensile stress for the diaphragm was extracted to  +31.5 MPa, where the pull-in voltage was 10.7 V. In succession, the dynamic response for the open-circuit sensitivity was modelled with an equivalent circuit model based on lumped parameters. The measured open-circuit sensitivity of  -45.1 dBV Pa-1 at 1 kHz with a bias of 9.6 V was only slightly different from the modelled sensitivity of  -45.0 dBV Pa-1. Thus, these results demonstrate that the proposed sensor is suitable for a front-end voice capture module.

  13. Costs and cost containment in nursing homes.

    PubMed Central

    Smith, H L; Fottler, M D

    1981-01-01

    The study examines the impact of structural and process variables on the cost of nursing home care and the utilization of various cost containment methods in 43 california nursing homes. Several predictors were statistically significant in their relation to cost per patient day. A diverse range of cost containment techniques was discovered along with strong predictors of the utilization of these techniques by nursing home administrators. The trade-off between quality of care and cost of care is discussed. PMID:7228713

  14. Unraveling Higher Education's Costs.

    ERIC Educational Resources Information Center

    Gordon, Gus; Charles, Maria

    1998-01-01

    The activity-based costing (ABC) method of analyzing institutional costs in higher education involves four procedures: determining the various discrete activities of the organization; calculating the cost of each; determining the cost drivers; tracing cost to the cost objective or consumer of each activity. Few American institutions have used the…

  15. Unraveling Higher Education's Costs.

    ERIC Educational Resources Information Center

    Gordon, Gus; Charles, Maria

    1998-01-01

    The activity-based costing (ABC) method of analyzing institutional costs in higher education involves four procedures: determining the various discrete activities of the organization; calculating the cost of each; determining the cost drivers; tracing cost to the cost objective or consumer of each activity. Few American institutions have used the…

  16. Solar array cost reduction

    NASA Technical Reports Server (NTRS)

    Bernatowicz, D. T.

    1972-01-01

    A brief description is given of the cost of solar power systems over the last decade and means by which cost reductions may be achieved in the future. Costs were broken down into nonrecurring and recurring costs for solar array, battery, and power conditioning. Correlation of costs with power were poor; however, costs correlated reasonably well with the array area.

  17. Equipment costs rise moderately

    SciTech Connect

    Farrar, G.

    1996-10-07

    The paper presents data on costs for the five equipment items which make up the Nelson-Farrar cost index. Equipment includes pumps and compressors, electrical machinery, engines, instruments, and heat exchangers. Data are also presented on refining costs, broken down into the following categories: operating costs, operating labor cost, construction labor cost, and equipment and materials.

  18. Costs and cost-minimisation analysis.

    PubMed

    Robinson, R

    1993-09-18

    Whatever kind of economic evaluation you plan to undertake, the costs must be assessed. In health care these are first of all divided into costs borne by the NHS (like drugs), by patients and their families (like travel), and by the rest of society (like health education). Next the costs have to be valued in monetary terms; direct costs, like wages, pose little problem, but indirect costs (like time spent in hospital) have to have values imputed to them. And that is not all: costs must be further subdivided into average, marginal, and joint costs, which help decisions on how much of a service should be provided. Capital costs (investments in plant, buildings, and machinery) are also important, as are discounting and inflation. In this second article in the series Ray Robinson defines the types of costs, their measurement, and how they should be valued in monetary terms.

  19. Costs and cost-minimisation analysis.

    PubMed Central

    Robinson, R

    1993-01-01

    Whatever kind of economic evaluation you plan to undertake, the costs must be assessed. In health care these are first of all divided into costs borne by the NHS (like drugs), by patients and their families (like travel), and by the rest of society (like health education). Next the costs have to be valued in monetary terms; direct costs, like wages, pose little problem, but indirect costs (like time spent in hospital) have to have values imputed to them. And that is not all: costs must be further subdivided into average, marginal, and joint costs, which help decisions on how much of a service should be provided. Capital costs (investments in plant, buildings, and machinery) are also important, as are discounting and inflation. In this second article in the series Ray Robinson defines the types of costs, their measurement, and how they should be valued in monetary terms. Images p727-a PMID:8401098

  20. Equipment Cost Estimator

    SciTech Connect

    2016-08-24

    The ECE application forecasts annual costs of preventive and corrective maintenance for budgeting purposes. Features within the application enable the user to change the specifications of the model to customize your forecast to best fit their needs and support “what if” analysis. Based on the user's selections, the ECE model forecasts annual maintenance costs. Preventive maintenance costs include the cost of labor to perform preventive maintenance activities at the specific frequency and labor rate. Corrective maintenance costs include the cost of labor and the cost of replacement parts. The application presents forecasted maintenance costs for the next five years in two tables: costs by year and costs by site.

  1. Predicting hospital accounting costs

    PubMed Central

    Newhouse, Joseph P.; Cretin, Shan; Witsberger, Christina J.

    1989-01-01

    Two alternative methods to Medicare Cost Reports that provide information about hospital costs more promptly but less accurately are investigated. Both employ utilization data from current-year bills. The first attaches costs to utilization data using cost-charge ratios from the previous year's cost report; the second uses charges from current year's bills. The first method is the more accurate of the two, but even using it, only 40 percent of hospitals had predicted costs within plus or minus 5 percent of actual costs. The feasibility and cost of obtaining cost reports from a small, fast-track sample of hospitals should be investigated. PMID:10313352

  2. Process-based costing.

    PubMed

    Lee, Robert H; Bott, Marjorie J; Forbes, Sarah; Redford, Linda; Swagerty, Daniel L; Taunton, Roma Lee

    2003-01-01

    Understanding how quality improvement affects costs is important. Unfortunately, low-cost, reliable ways of measuring direct costs are scarce. This article builds on the principles of process improvement to develop a costing strategy that meets both criteria. Process-based costing has 4 steps: developing a flowchart, estimating resource use, valuing resources, and calculating direct costs. To illustrate the technique, this article uses it to cost the care planning process in 3 long-term care facilities. We conclude that process-based costing is easy to implement; generates reliable, valid data; and allows nursing managers to assess the costs of new or modified processes.

  3. Price and cost estimation

    NASA Technical Reports Server (NTRS)

    Stewart, R. D.

    1979-01-01

    Price and Cost Estimating Program (PACE II) was developed to prepare man-hour and material cost estimates. Versatile and flexible tool significantly reduces computation time and errors and reduces typing and reproduction time involved in preparation of cost estimates.

  4. Life Cycle Costing.

    ERIC Educational Resources Information Center

    McCraley, Thomas L.

    1985-01-01

    Life cycle costing establishes a realistic comparison of the cost of owning and operating products. The formula of initial cost plus maintenance plus operation divided by useful life identifies the best price over the lifetime of the product purchased. (MLF)

  5. Price and cost estimation

    NASA Technical Reports Server (NTRS)

    Stewart, R. D.

    1979-01-01

    Price and Cost Estimating Program (PACE II) was developed to prepare man-hour and material cost estimates. Versatile and flexible tool significantly reduces computation time and errors and reduces typing and reproduction time involved in preparation of cost estimates.

  6. Measuring Library Costs.

    ERIC Educational Resources Information Center

    Mlynarczyk, Frank, Jr.

    Based on the premise that cost measurement for a library can be performed in the same manner as for an industrial organization, this paper presents a hypothetical cost determination problem of a small company which produces bricks. A summary of the five steps taken to develop the various cost figures are: (1) Assign all cost items to the…

  7. Design-to-cost

    NASA Technical Reports Server (NTRS)

    Bradley, F. E.

    1974-01-01

    Attempts made to design to costs equipment, vehicles and subsystems for various space projects are discussed. A systematic approach, based on mission requirement analysis, definition of a mission baseline design, benefit and cost analysis, and a benefit-cost analysis was proposed for implementing the cost control program.

  8. Costing for Policy Analysis.

    ERIC Educational Resources Information Center

    National Association of College and University Business Officers, Washington, DC.

    Cost behavior analysis, a costing process that can assist managers in estimating how certain institutional costs change in response to volume, policy, and environmental factors, is described. The five steps of this approach are examined, and the application of cost behavior analysis at four college-level settings is documented. The institutions…

  9. GME: at what cost?

    PubMed

    Young, David W

    2003-11-01

    Current computing methods impede determining the real cost of graduate medical education. However, a more accurate estimate could be obtained if policy makers would allow for the application of basic cost-accounting principles, including consideration of department-level costs, unbundling of joint costs, and other factors.

  10. OOTW COST TOOLS

    SciTech Connect

    HARTLEY, D.S.III; PACKARD, S.L.

    1998-09-01

    This document reports the results of a study of cost tools to support the analysis of Operations Other Than War (OOTW). It recommends the continued development of the Department of Defense (DoD) Contingency Operational Support Tool (COST) as the basic cost analysis tool for 00TWS. It also recommends modifications to be included in future versions of COST and the development of an 00TW mission planning tool to supply valid input for costing.

  11. Cost Benefit Analysis vs Cost Consequences Analysis.

    ERIC Educational Resources Information Center

    Wilkinson, David

    1999-01-01

    Describes cost consequences analysis as a means to estimate whether the value of results obtained is worth the investment. Discusses how CCA differs from other evaluation tools, return on investment, and theoretical underpinnings of cost benefit analysis (CBA), and contends that there is no substantive difference between CCA and CBA. (Author/LRW)

  12. Total Cost Management: Analyzing Operational Support Costs.

    ERIC Educational Resources Information Center

    Jenny, Hans J.

    1996-01-01

    Total cost management, an innovation useful in higher education, is best implemented in the institution's support services. Total cost management is the practice of analyzing and improving an institution's financial and qualitative performance when producing a particular product or service, paying attention to the complete work process and all…

  13. Measurement of costs.

    PubMed

    Riewpaiboon, Arthorn

    2008-06-01

    Costing plays an important role in health economics, particularly economic evaluation. However, there are some controversial issues: concepts, methods and reference values. Hence, it is pivotal to standardize can be con costing methods and use these as national guidelines to produce comparable studies. This report is divided perspectives. into 3 parts: theoretical issues, international guidelines comparison, and recommendations for the Thai technology assessment guidelines. Each section is composed of three general costing steps: identification, appropriate, measuring and valuation. It is recommended to measure economic or opportunity cost mainly in societal perspective. Cost category is composed of direct medical, direct non-medical and indirect costs. The level of reliability of each kind of costing source data is provided. Valuation of resource use based on national government, standard cost menu is recommended for national policy making. The recommendations on cost measurement are appropriate for the Thai context and in the current situation.

  14. Net Shape Spin Formed Cryogenic Aluminum Lithium Cryogenic Tank Domes for Lower Cost Higher Performance Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Curreri, Peter A.; Hoffman, Eric; Domack, Marcia; Brewster, Jeb; Russell, Carolyn

    2013-01-01

    With the goal of lower cost (simplified manufacturing and lower part count) and higher performance (higher strength to weight alloys) the NASA Technical Maturation Program in 2006 funded a proposal to investigate spin forming of space launch vehicle cryogenic tank domes. The project funding continued under the NASA Exploration Technology Development Program through completion in FY12. The first phase of the project involved spin forming of eight, 1 meter diameter "path finder" domes. Half of these were processed using a concave spin form process (MT Aerospace, Augsburg Germany) and the other half using a convex process (Spincraft, Boston MA). The convex process has been used to produce the Ares Common Bulkhead and the concave process has been used to produce dome caps for the Space Shuttle light weight external tank and domes for the NASDA H2. Aluminum Lithium material was chosen because of its higher strength to weight ratio than the Aluminum 2219 baseline. Aluminum lithium, in order to obtain the desired temper (T8), requires a cold stretch after the solution heat treatment and quench. This requirement favors the concave spin form process which was selected for scale up. This paper describes the results of processing four, 5.5 meter diameter (upper stage scale) net shaped spin formed Aluminum Lithium domes. In order to allow scalability beyond the limits of foundry and rolling mills (about 12 foot width) the circular blank contained one friction stir weld (heavy lifter scales require a flat blank containing two welds). Mechanical properties data (tensile, fracture toughness, stress corrosion, and simulated service testing) for the parent metal and weld will also be discussed.

  15. Structure of drying costs

    SciTech Connect

    Sztabert, Z.T.

    1996-05-01

    A knowledge of cost structure and cost behavior is necessary in the management activities, particularly in the domain of investment or production decision making, as well as in the areas of production cost planning and control. Prediction and analysis of values of cost components for different technologies of drying are important when selection of a drying method and drying equipment should be done. Cost structures of lumber and coal drying processes together with an application of the factor method for prediction of the drying cost are presented.

  16. Clinical process cost analysis.

    PubMed

    Marrin, C A; Johnson, L C; Beggs, V L; Batalden, P B

    1997-09-01

    New systems of reimbursement are exerting enormous pressure on clinicians and hospitals to reduce costs. Using cheaper supplies or reducing the length of stay may be a satisfactory short-term solution, but the best strategy for long-term success is radical reduction of costs by reengineering the processes of care. However, few clinicians or institutions know the actual costs of medical care; nor do they understand, in detail, the activities involved in the delivery of care. Finally, there is no accepted method for linking the two. Clinical process cost analysis begins with the construction of a detailed flow diagram incorporating each activity in the process of care. The cost of each activity is then calculated, and the two are linked. This technique was applied to Diagnosis Related Group 75 to analyze the real costs of the operative treatment of lung cancer at one institution. Total costs varied between $6,400 and $7,700. The major driver of costs was personnel time, which accounted for 55% of the total. Forty percent of the total cost was incurred in the operating room. The cost of care decreased progressively during hospitalization. Clinical process cost analysis provides detailed information about the costs and processes of care. The insights thus obtained may be used to reduce costs by reengineering the process.

  17. Cost of energy evaluation

    NASA Technical Reports Server (NTRS)

    Hasbrouck, T. M.

    1979-01-01

    The estimated cost per kilowatt hour, the wind resources in the utilities service area, and the reliability of the units are considered in computing the cost of energy of the wind turbine generator system.

  18. Managing Information On Costs

    NASA Technical Reports Server (NTRS)

    Taulbee, Zoe A.

    1990-01-01

    Cost Management Model, CMM, software tool for planning, tracking, and reporting costs and information related to costs. Capable of estimating costs, comparing estimated to actual costs, performing "what-if" analyses on estimates of costs, and providing mechanism to maintain data on costs in format oriented to management. Number of supportive cost methods built in: escalation rates, production-learning curves, activity/event schedules, unit production schedules, set of spread distributions, tables of rates and factors defined by user, and full arithmetic capability. Import/export capability possible with 20/20 Spreadsheet available on Data General equipment. Program requires AOS/VS operating system available on Data General MV series computers. Written mainly in FORTRAN 77 but uses SGU (Screen Generation Utility).

  19. Design to Cost and Life Cycle Cost.

    DTIC Science & Technology

    1980-07-01

    Command (NAVAIR) to estimate Operating and Support (O&S) cost. To a large degree, this improvement is due to the appearance in Fiscal Year (FY) 1975 of...they be based on existing data. These reports are available for four full years plus the transition fiscal year for Navy aircraft. While the VAMOSC MS...All costs are in Fiscal Year 80 $. Figure 7 For the purposes of this example, the baseline and hypothetical equipment were divided into major

  20. Cost and Price Collaboration

    DTIC Science & Technology

    2016-04-30

    and individual relationships. This paper examines the state of current collaboration between price and cost analysts in four Army ground vehicle...detailed costs for labor, material, and overhead, but the CSDRs also provide costs by a standardized detailed work breakdown structure. Currently , this...information in addition to the PNMs that supported their cost and budgeting efforts. Current Contractor Rates enabled the estimation of current

  1. Flash xenon CPV simulator with low-cost elastic bent-trough mirrors

    NASA Astrophysics Data System (ADS)

    Yamada, Noboru; Okamoto, Kazuya; Ijiro, Toshikazu; Kiryu, Mitsugu; Yoshida, Takanori

    2013-09-01

    In the research and development of concentrator photovoltaic (CPV) systems, a highly collimated artificial sunlight source with a wide irradiated area is very helpful in the reliable evaluation of module efficiency and optical performance. To collimate the light, a conventional flash xenon CPV simulator uses an expensive large concave mirror. This paper introduces a new flash xenon CPV simulator that consists of two low-cost elastic bent-trough mirrors. The prototype simulator achieved an irradiance deviation of less than 10%, collimation of 0.228° - 0.330°, and good spectral matching at an irradiated area of 700 mm × 500 mm. The major drawback of the present concept is that the flash lamp must provide higher emissive power than the conventional method because of the light attenuation caused by the two reflections from the mirrors.

  2. Estimating 'costs' for cost-effectiveness analysis.

    PubMed

    Miners, Alec

    2008-01-01

    Since 1999, the National Institute for Health and Clinical Excellence (NICE) Technology Appraisal Programme has been charged with producing guidance for the NHS in England and Wales on the appropriate use of new and existing healthcare programmes. Guidance is based on an assessment of a number of factors, including cost effectiveness. The identification, measurement and valuation of costs are important components of any cost-effectiveness analysis. However, working through these steps raises a number of important methodological questions. For example, how should 'future' resource use be estimated, and is there a need to consider all 'future' costs? Given that NICE produces national guidance, should national unit cost data be used to value resources or should local variations in negotiated prices be taken into account? This paper was initially prepared as a briefing paper as part of the process of updating NICE's 2004 Guide to the Methods of Technology Appraisal for a workshop on 'costs'. It outlines the issues that were raised in the original briefing paper and the subsequent questions that were discussed at the workshop.

  3. COST OF MTBE REMEDIATION

    EPA Science Inventory

    Widespread contamination of methyl tert-butyl ether (MTBE) in ground water has raised concerns about the increased cost of remediation of MTBE releases compared to BTEX-only sites. To evaluate these cost, cost information for 311 sites was furnished by U.S. EPA Office of Undergr...

  4. Educational Cost Analysis.

    ERIC Educational Resources Information Center

    Flynn, Donald L.

    Traditional approaches to the cost analysis of educational programs involve examining annual budgets. Such approaches do not properly consider the cost of either new capital expenditures or the current value of previously purchased items. This paper presents the methodology for a new approach to educational cost analysis that identifies the actual…

  5. Unit Cost Compendium Calculations

    EPA Pesticide Factsheets

    The Unit Cost Compendium (UCC) Calculations raw data set was designed to provide for greater accuracy and consistency in the use of unit costs across the USEPA Office of Resource Conservation and Recovery (ORCR), as well as increased accessibility to unit costs inside and outside the ORCR.

  6. COST OF MTBE REMEDIATION

    EPA Science Inventory

    Widespread contamination of methyl tert-butyl ether (MTBE) in ground water has raised concerns about the increased cost of remediation of MTBE releases compared to BTEX-only sites. To evaluate these cost, cost information for 311 sites was furnished by U.S. EPA Office of Undergr...

  7. Opportunity Cost: A Reexamination

    ERIC Educational Resources Information Center

    Parkin, Michael

    2016-01-01

    Is opportunity cost an ambiguous and arbitrary concept or a simple, straightforward, and fruitful one? This reexamination of opportunity cost addresses this question, and shows that opportunity cost is an ambiguous concept because "two" definitions are in widespread use. One of the definitions is indeed simple, fruitful, and one that…

  8. Conceptual Cost Estimating

    NASA Technical Reports Server (NTRS)

    Brown, J. A.

    1983-01-01

    Kennedy Space Center data aid in efficient construction-cost managment. Report discusses development and use of NASA TR-1508, Kennedy Space Center Aerospace Construction price book for preparing conceptual budget, funding cost estimating, and preliminary cost engineering reports. Report based on actual bid prices and Government estimates.

  9. Trends in Institutional Costs.

    ERIC Educational Resources Information Center

    Kirshstein, Rita J.; And Others

    This report describes the cost of nonprofit undergraduate collegiate education, how that cost has grown throughout the 1980s, and reasons for increases in college costs. The study analyzed multiple data sources to determine that college tuition growth has outpaced general price inflation since about 1980, but the American public believes that the…

  10. Cost Planning System

    ERIC Educational Resources Information Center

    Bowen, Brian

    1974-01-01

    The third installment of a Building Cost File points out the necessity of providing a framework for overall cost control during design. A cost analysis (see EA 504 571) illustrates how the use of construction elements or subsystems provide a suitable means. Other related articles are EA 503 949, 950, 951, and EA 504 578-579. (MF)

  11. Costing and pricing.

    PubMed

    Jones, T

    1993-01-01

    With spreadsheets at the ready, accountants in the NHS are waiting to apply the uniform costing methodology emerging from the National Steering Group on Costing. Before the money-number-crunchers hijack its eventual final report Costing for contracts, general managers need to work out the implications for their role in pricing services and contracts.

  12. Plagiarism and Costs

    ERIC Educational Resources Information Center

    Liebler, Robert

    2009-01-01

    It is costly for faculty to deal with cheating. Keith-Spiegel et al. (1998) identified several of these costs and argued that they can be grouped into four categories: emotionality, difficult, fear, and denial. I argue that the emotional and fear costs for faculty make it unlikely that the common approaches to dealing with plagiarism will be…

  13. Opportunity Cost: A Reexamination

    ERIC Educational Resources Information Center

    Parkin, Michael

    2016-01-01

    Is opportunity cost an ambiguous and arbitrary concept or a simple, straightforward, and fruitful one? This reexamination of opportunity cost addresses this question, and shows that opportunity cost is an ambiguous concept because "two" definitions are in widespread use. One of the definitions is indeed simple, fruitful, and one that…

  14. Conceptual Cost Estimating

    NASA Technical Reports Server (NTRS)

    Brown, J. A.

    1983-01-01

    Kennedy Space Center data aid in efficient construction-cost managment. Report discusses development and use of NASA TR-1508, Kennedy Space Center Aerospace Construction price book for preparing conceptual budget, funding cost estimating, and preliminary cost engineering reports. Report based on actual bid prices and Government estimates.

  15. Power Plant Cycling Costs

    SciTech Connect

    Kumar, N.; Besuner, P.; Lefton, S.; Agan, D.; Hilleman, D.

    2012-07-01

    This report provides a detailed review of the most up to date data available on power plant cycling costs. The primary objective of this report is to increase awareness of power plant cycling cost, the use of these costs in renewable integration studies and to stimulate debate between policymakers, system dispatchers, plant personnel and power utilities.

  16. Melanoma Treatment Costs

    PubMed Central

    Guy, Gery P.; Ekwueme, Donatus U.; Tangka, Florence K.; Richardson, Lisa C.

    2015-01-01

    Context Melanoma is the most deadly form of skin cancer and an important public health concern. Given the substantial health burden associated with melanoma, it is important to examine the economic costs associated with its treatment. The purpose of the current study was to systematically review the literature on the direct medical care costs of melanoma. Evidence acquisition A systematic review was performed using multiple databases including MEDLINE, Embase, CINAHL, and Econlit. Nineteen articles on the direct medical costs of melanoma were identified. Evidence synthesis Detailed information on the study population, study country/setting, study perspective, costing approach, disease severity (stage), and key study results were abstracted. The overall costs of melanoma were examined as well as per-patient costs, costs by phase of care, stage of diagnosis, and setting/type of care. Among studies examining all stages of melanoma, annual treatment costs ranged from $44.9 million among Medicare patients with existing cases to $932.5 million among newly diagnosed cases across all age groups. Conclusions Melanoma leads to substantial direct medical care costs, with estimates varying widely because of the heterogeneity across studies in terms of the study setting, populations studied, costing approach, and study methods. Melanoma treatment costs varied by phase of care and stage at diagnoses; costs were highest among patients diagnosed with late-stage disease and in the initial and terminal phases of care. Aggregate treatment costs were generally highest in the outpatient/office-based setting; per-patient/per-case treatment costs were highest in the hospital inpatient setting. Given the substantial costs of treating melanoma, public health strategies should include efforts to enhance both primary prevention (reduction of ultraviolet light exposure) and secondary prevention (earlier detection) of melanoma. PMID:23079178

  17. Ion propulsion cost effectivity

    NASA Technical Reports Server (NTRS)

    Zafran, S.; Biess, J. J.

    1978-01-01

    Ion propulsion modules employing 8-cm thrusters and 30-cm thrusters were studied for Multimission Modular Spacecraft (MMS) applications. Recurring and nonrecurring cost elements were generated for these modules. As a result, ion propulsion cost drivers were identified to be Shuttle charges, solar array, power processing, and thruster costs. Cost effective design approaches included short length module configurations, array power sharing, operation at reduced thruster input power, simplified power processing units, and power processor output switching. The MMS mission model employed indicated that nonrecurring costs have to be shared with other programs unless the mission model grows. Extended performance missions exhibited the greatest benefits when compared with monopropellant hydrazine propulsion.

  18. Cost characteristics of hospitals.

    PubMed

    Smet, Mike

    2002-09-01

    Modern hospitals are complex multi-product organisations. The analysis of a hospital's production and/or cost structure should therefore use the appropriate techniques. Flexible functional forms based on the neo-classical theory of the firm seem to be most suitable. Using neo-classical cost functions implicitly assumes minimisation of (variable) costs given that input prices and outputs are exogenous. Local and global properties of flexible functional forms and short-run versus long-run equilibrium are further issues that require thorough investigation. In order to put the results based on econometric estimations of cost functions in the right perspective, it is important to keep these considerations in mind when using flexible functional forms. The more recent studies seem to agree that hospitals generally do not operate in their long-run equilibrium (they tend to over-invest in capital (capacity and equipment)) and that it is therefore appropriate to estimate a short-run variable cost function. However, few studies explicitly take into account the implicit assumptions and restrictions embedded in the models they use. An alternative method to explain differences in costs uses management accounting techniques to identify the cost drivers of overhead costs. Related issues such as cost-shifting and cost-adjusting behaviour of hospitals and the influence of market structure on competition, prices and costs are also discussed shortly.

  19. Concepts of Cost and Cost Analysis for Higher Education.

    ERIC Educational Resources Information Center

    Brinkman, Paul T.; Allen, Richard H.

    1986-01-01

    Concepts of costs and cost analysis in higher education are examined, along with how to prepare for a cost study. Specific cost analysis techniques are identified, along with types of data generated and potential problems. In preparing for cost studies, it is important to consider: purpose, types of cost analysis, types of cost, common…

  20. Cost effective lighting

    SciTech Connect

    Morse, O.; Verderber, R.

    1987-07-01

    Long-life replacement lamps for the incandescent lamp have been evaluated with regard to their cost effectiveness. The replacements include the use of energy buttons that extend lamp life as well as an adaptive fluorescent circline lamp that will fit into existing incandescent lamp sockets. The initial, operating, and replacement costs for one million lumen-hours are determined for each lamp system. We find the most important lighting cost component is the operating cost. Using lamps that are less efficient or devices that cause lamps to operate less efficiently are not cost-effective. The adaptive fluorescent circline lamp, even at an initial cost of $15.00, is the most cost effective source of illumination compared to the incandescent lamp and lamp systems examined. 3 refs., 6 tabs.

  1. Cost optimization in anaesthesia.

    PubMed

    Bauer, M; Bach, A; Martin, E; Böttiger, B W

    2001-04-01

    As a result of the progress which has been made in medicine and technology and the increase in morbidity associated this demographic development, the need and thus the costs for medical care have increased as well. The financial resources which are available for medical care, however, are still limited and hence the funds which are available must be distributed more efficiently. Cost optimisation measures can help make better use of the profitability reserves in hospitals. The authors show how costs can be optimised in the anaesthesiology department of a clinic. Pharmacoeconomic evaluation of the new inhalation anaesthetics shows an example of how the cost structures in anaesthesia can be made more obvious and potential ways savings be implemented. To reduce material and personnel costs, a more rational means of internal process management is presented. According to cost-effectiveness analysis, medications are not divided into the categories inexpensive and expensive but rather cost-effective or non-cost-effective. By selecting a cost-effective drug it is possible to reduce cost at a hospital. For example, sevoflurane at a fresh gas flow of below 3 l/min has been shown to be a cost-effective inhalation anaesthetic which, in terms of the economics, is also superior to intravenous anaesthesia with propofol. In addition to these measures of reducing material costs, other examples are given of how personnel costs can be reduced by optimising work procedures: e.g. effective operating theatre co-ordination, short switchover times by overlapping anaesthesia induction and the use of multifunctional personnel. The gain in productivity which is a result of these measures can positively affect profits, and by optimising the organisation of procedures to shorten the times required to carry out a procedure, costs can be reduced.

  2. Costs optimization in anaesthesia.

    PubMed

    Martelli, Alessandra

    2015-04-27

    The aim of this study is to analyze the direct cost of different anaesthetic techniques used within the Author's hospital setting and compare with costs reported in the literature. Mean cost of drugs and devices used in our local Department of Anaesthesia was considered in the present study. All drugs were supplied by the in-house Pharmacy Service of Parma's General Hospital. All calculation have been made using an hypothetical ASA1 patient weighting 70 kg. The quality of consumption and cost of inhalation anaesthesia with sevoflurane or desflurane at different fresh gas flow were analyzed, and the cost of total venous anaesthesia (TIVA) using propofol and remifentanil with balanced anaesthesia were also analyzed. In addition, direct costs of general, spinal and sciatic-femoral nerve block anaesthesia used for common plastic surgery procedures were assessed. The results of our study show that the cost of inhalational anaesthesia decreases using fresh gas flow below 1L, and the use of desflurane is more expensive. In our Hospital, the cost of TIVA is more or less equivalent to the costs of balanced anaesthesia with sevoflurane in surgical procedure lasting more than five hours. The direct cost was lower for the spinal anaesthesia compared with general anaesthesia and sciatic- femoral nerve block for some surgical procedures. (www.actabiomedica.it).

  3. Heliostat cost optimization study

    NASA Astrophysics Data System (ADS)

    von Reeken, Finn; Weinrebe, Gerhard; Keck, Thomas; Balz, Markus

    2016-05-01

    This paper presents a methodology for a heliostat cost optimization study. First different variants of small, medium sized and large heliostats are designed. Then the respective costs, tracking and optical quality are determined. For the calculation of optical quality a structural model of the heliostat is programmed and analyzed using finite element software. The costs are determined based on inquiries and from experience with similar structures. Eventually the levelised electricity costs for a reference power tower plant are calculated. Before each annual simulation run the heliostat field is optimized. Calculated LCOEs are then used to identify the most suitable option(s). Finally, the conclusions and findings of this extensive cost study are used to define the concept of a new cost-efficient heliostat called `Stellio'.

  4. Schizophrenia costs and treatment cost-effectiveness.

    PubMed

    Knapp, M

    2000-01-01

    The paper sets out to summarize evidence on the costs of schizophrenia and on the cost-effectiveness of three broad treatment areas. Evidence from a number of countries was examined, both published and unpublished, and systematic reviews and meta-analyses were consulted. The costs of schizophrenia are high and wide-ranging. They fall not only to health-care agencies but also to other parts of the public sector, to families, to sufferers themselves and to the wider society. However, there are interventions--a counselling intervention to address non-compliance with medication, family interventions to reduce levels of expressed emotion, and atypical antipsychotic drugs--that have been found to be not only effective (improving patient outcomes) but also appear to be cost-effective. Resource constraints and policy pressures make it increasingly common for economic as well as clinical questions to be asked about new modes of treatment. This is the new reality of mental health practice. Reliable evidence is now available to address these economic questions and can be factored into decision-making processes.

  5. Low cost concentrator

    NASA Technical Reports Server (NTRS)

    Bedard, R. J., Jr.; Overly, P.

    1981-01-01

    The key to concentrator cost effectiveness is the proper design of the reflector surface panels. The low cost concentrator reflective surface design is based on use of a thin, backsilvered mirror glass reflector bonded to a molded structural plastic substrate. This combination of reflective panel material offers excellent optical performance at low cost. The design approach, rationale for the selected configuration, and the development status are described. Reflective panel development and demonstration results are also presented.

  6. NASA's attack on costs

    NASA Technical Reports Server (NTRS)

    Low, George M.

    1994-01-01

    This article's concern is regarding the high costs of space travel and the need to minimize or reduce these costs in order to effectively provide the continuation of the space programs and space exploration needs of the future. Discussed is the possibility and need to optimize payloads in order to lower the costs associated with them. Design phase principles and implementation phase points are discussed.

  7. LMFBR fuel component costs

    SciTech Connect

    Epperson, E.M.; Borisch, R.R.; Rice, L.H.

    1981-10-29

    A significant portion of the cost of fabricating LMFBR fuels is in the non-fuel components such as fuel pin cladding, fuel assembly ducts and end fittings. The contribution of these to fuel fabrication costs, based on FFTF experience and extrapolated to large LMFBR fuel loadings, is discussed. The extrapolation considers the expected effects of LMFBR development programs in progress on non-fuel component costs.

  8. 76 FR 81295 - Cost Accounting Standards: Cost Accounting Standards 412 and 413-Cost Accounting Standards...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-27

    ... 9904 Cost Accounting Standards: Cost Accounting Standards 412 and 413--Cost Accounting Standards... Policy 48 CFR Part 9904 Cost Accounting Standards: Cost Accounting Standards 412 and 413--Cost Accounting Standards Pension Harmonization Rule AGENCY: Cost Accounting Standards Board, Office of Federal Procurement...

  9. Cost model for biobanks.

    PubMed

    Gonzalez-Sanchez, M Beatriz; Lopez-Valeiras, Ernesto; Morente, Manuel M; Fernández Lago, Orlando

    2013-10-01

    Current economic conditions and budget constraints in publicly funded biomedical research have brought about a renewed interest in analyzing the cost and economic viability of research infrastructures. However, there are no proposals for specific cost accounting models for these types of organizations in the international scientific literature. The aim of this paper is to present the basis of a cost analysis model useful for any biobank regardless of the human biological samples that it stores for biomedical research. The development of a unique cost model for biobanks can be a complicated task due to the diversity of the biological samples they store. Different types of samples (DNA, tumor tissues, blood, serum, etc.) require different production processes. Nonetheless, the common basic steps of the production process can be identified. Thus, the costs incurred in each step can be analyzed in detail to provide cost information. Six stages and four cost objects were obtained by taking the production processes of biobanks belonging to the Spanish National Biobank Network as a starting point. Templates and examples are provided to help managers to identify and classify the costs involved in their own biobanks to implement the model. The application of this methodology will provide accurate information on cost objects, along with useful information to give an economic value to the stored samples, to analyze the efficiency of the production process and to evaluate the viability of some sample collections.

  10. Designer's unified cost model

    NASA Technical Reports Server (NTRS)

    Freeman, William T.; Ilcewicz, L. B.; Swanson, G. D.; Gutowski, T.

    1992-01-01

    A conceptual and preliminary designers' cost prediction model has been initiated. The model will provide a technically sound method for evaluating the relative cost of different composite structural designs, fabrication processes, and assembly methods that can be compared to equivalent metallic parts or assemblies. The feasibility of developing cost prediction software in a modular form for interfacing with state of the art preliminary design tools and computer aided design programs is being evaluated. The goal of this task is to establish theoretical cost functions that relate geometric design features to summed material cost and labor content in terms of process mechanics and physics. The output of the designers' present analytical tools will be input for the designers' cost prediction model to provide the designer with a data base and deterministic cost methodology that allows one to trade and synthesize designs with both cost and weight as objective functions for optimization. The approach, goals, plans, and progress is presented for development of COSTADE (Cost Optimization Software for Transport Aircraft Design Evaluation).

  11. Designers' unified cost model

    NASA Technical Reports Server (NTRS)

    Freeman, W.; Ilcewicz, L.; Swanson, G.; Gutowski, T.

    1992-01-01

    The Structures Technology Program Office (STPO) at NASA LaRC has initiated development of a conceptual and preliminary designers' cost prediction model. The model will provide a technically sound method for evaluating the relative cost of different composite structural designs, fabrication processes, and assembly methods that can be compared to equivalent metallic parts or assemblies. The feasibility of developing cost prediction software in a modular form for interfacing with state-of-the-art preliminary design tools and computer aided design programs is being evaluated. The goal of this task is to establish theoretical cost functions that relate geometric design features to summed material cost and labor content in terms of process mechanics and physics. The output of the designers' present analytical tools will be input for the designers' cost prediction model to provide the designer with a database and deterministic cost methodology that allows one to trade and synthesize designs with both cost and weight as objective functions for optimization. This paper presents the team members, approach, goals, plans, and progress to date for development of COSTADE (Cost Optimization Software for Transport Aircraft Design Evaluation).

  12. Cost Containment in Europe

    PubMed Central

    Culyer, A. J.

    1989-01-01

    Health care cost containment is not in itself a sensible policy objective, because any assessment of the appropriateness of health care expenditure in aggregate, as of that on specific programs, requires a balancing of costs and benefits at the margin. International data on expenditures can, however, provide indications of the likely impact on costs and expenditures of structural features of health care systems. Data from the Organization for Economic Cooperation and Development for both European countries and a wider set are reviewed, and some current policies in Europe that are directed at controlling health care costs are outlined. PMID:10313433

  13. Avoidable waste management costs

    SciTech Connect

    Hsu, K.; Burns, M.; Priebe, S.; Robinson, P.

    1995-01-01

    This report describes the activity based costing method used to acquire variable (volume dependent or avoidable) waste management cost data for routine operations at Department of Energy (DOE) facilities. Waste volumes from environmental restoration, facility stabilization activities, and legacy waste were specifically excluded from this effort. A core team consisting of Idaho National Engineering Laboratory, Los Alamos National Laboratory, Rocky Flats Environmental Technology Site, and Oak Ridge Reservation developed and piloted the methodology, which can be used to determine avoidable waste management costs. The method developed to gather information was based on activity based costing, which is a common industrial engineering technique. Sites submitted separate flow diagrams that showed the progression of work from activity to activity for each waste type or treatability group. Each activity on a flow diagram was described in a narrative, which detailed the scope of the activity. Labor and material costs based on a unit quantity of waste being processed were then summed to generate a total cost for that flow diagram. Cross-complex values were calculated by determining a weighted average for each waste type or treatability group based on the volume generated. This study will provide DOE and contractors with a better understanding of waste management processes and their associated costs. Other potential benefits include providing cost data for sites to perform consistent cost/benefit analysis of waste minimization and pollution prevention (WMIN/PP) options identified during pollution prevention opportunity assessments and providing a means for prioritizing and allocating limited resources for WMIN/PP.

  14. Cost of mask fabrication

    NASA Astrophysics Data System (ADS)

    Trybula, Walter J.; Dance, Daren L.

    1997-07-01

    The development of the cost of ownership methodology provided the semiconductor industry with a process that is employed to evaluate the life cycle costs of any particular equipment. Applying this technique has provided a cost focus on areas of potential improvement. The existing methodology is equipment centric. The limitation of this process is that there has not been a means of evaluating the impact of the cost of ownership for a process. An evaluation of process requirements indicated that such a tool would provide an advantage for evaluating not only the process flow cost but also allocate the individual cost of ownership values according to the planned volumes and yields. This would not be the comprehensive evaluation that can be done with dynamic simulation, but a static first approximation at total process costs based on a combined process flow. This paper describes the application of this new process to the development of the process cost of ownership to the optical mask production process. The program employed in work, PRO COOLTM, was developed by WWK in conjunction with SEMATECH. This paper describes the application of process cost of ownership to the optical mask production process sequence. Using a generic mask fabrication flow, process sequence cost of ownership analysis is used to identify cost drivers, throughput limitations, and process cost sensitivities. This generic process flow consists of the data evaluation and general number crunching requirements at the beginning of the process, followed by exposure, develop, inspection, measure, CD, pelliclize, inspect, and ship. Understanding of the relationship of these factors will help evaluate future mask fabrication technologies and requirements. Analyzing a generic optical mask production process sequence showed that the simple approach of adding process step cost of ownership values underestimates the process cost of ownership. Thus a complete analysis must consider the cost of unused capacity in

  15. Updated Conceptual Cost Estimating

    NASA Technical Reports Server (NTRS)

    Brown, J. A.

    1987-01-01

    16-page report discusses development and use of NASA TR-1508, the Kennedy Space Center Aerospace Construction Price Book for preparing conceptual, budget, funding, cost-estimating, and preliminary cost-engineering reports. Updated annually from 1974 through 1985 with actual bid prices and government estimates. Includes labor and material quantities and prices with contractor and subcontractor markups for buildings, facilities, and systems at Kennedy Space Center. While data pertains to aerospace facilities, format and cost-estimating techniques guide estimation of costs in other construction applications.

  16. ''When Cost Measures Contradict''

    SciTech Connect

    Montgomery, W. D.; Smith, A. E.; Biggar, S. L.; Bernstein, P. M.

    2003-05-09

    When regulators put forward new economic or regulatory policies, there is a need to compare the costs and benefits of these new policies to existing policies and other alternatives to determine which policy is most cost-effective. For command and control policies, it is quite difficult to compute costs, but for more market-based policies, economists have had a great deal of success employing general equilibrium models to assess a policy's costs. Not all cost measures, however, arrive at the same ranking. Furthermore, cost measures can produce contradictory results for a specific policy. These problems make it difficult for a policy-maker to determine the best policy. For a cost measures to be of value, one would like to be confident of two things. First one wants to be sure whether the policy is a winner or loser. Second, one wants to be confident that a measure produces the correct policy ranking. That is, one wants to have confidence in a policy measure's ability to correctly rank policies from most beneficial to most harmful. This paper analyzes empirically these two properties of different costs measures as they pertain to assessing the costs of the carbon abatement policies, especially the Kyoto Protocol, under alternative assumptions about implementation.

  17. 45 CFR 149.115 - Cost threshold and cost limit.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 1 2011-10-01 2011-10-01 false Cost threshold and cost limit. 149.115 Section 149... REQUIREMENTS FOR THE EARLY RETIREE REINSURANCE PROGRAM Reinsurance Amounts § 149.115 Cost threshold and cost limit. The following cost threshold and cost limits apply individually, to each early retiree as...

  18. Improving hospital cost accounting with activity-based costing.

    PubMed

    Chan, Y C

    1993-01-01

    In this article, activity-based costing, an approach that has proved to be an improvement over the conventional costing system in product costing, is introduced. By combining activity-based costing with standard costing, health care administrators can better plan and control the costs of health services provided while ensuring that the organization's bottom line is healthy.

  19. Transaction Cost Economics (TCE) and Cost Estimation Methodology

    DTIC Science & Technology

    2008-05-15

    TRANSACTION COST ECONOMICS (TCE) – MAKE OR BUY , AND ASSOCIATED DIFFICULTIES • OUR VIEW OF TCE AND COST ...1 Transaction Cost Economics (TCE) and Cost Estimation Methodology Diana Angelis, Francois Melese (DRMI) John Dillard, Chip Franck (GSBPP) NAVAL...TITLE AND SUBTITLE Transaction Cost Economics (TCE) and Cost Estimation Methodology 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  20. What Does it Really Cost? Allocating Indirect Costs.

    ERIC Educational Resources Information Center

    Snyder, Herbert; Davenport, Elisabeth

    1997-01-01

    Better managerial control in terms of decision making and understanding the costs of a system/service result from allocating indirect costs. Allocation requires a three-step process: selecting cost objectives, pooling related overhead costs, and selecting costs bases to connect the objectives to the pooled costs. Argues that activity-based costing…

  1. What Does it Really Cost? Allocating Indirect Costs.

    ERIC Educational Resources Information Center

    Snyder, Herbert; Davenport, Elisabeth

    1997-01-01

    Better managerial control in terms of decision making and understanding the costs of a system/service result from allocating indirect costs. Allocation requires a three-step process: selecting cost objectives, pooling related overhead costs, and selecting costs bases to connect the objectives to the pooled costs. Argues that activity-based costing…

  2. ECOM - ESA's cost modelling

    NASA Astrophysics Data System (ADS)

    Fatelnig, Peter K.

    1996-01-01

    ESA, as an international procurement agency dealing with more than 1200 companies at the same time, must have the ability to assess the price for a product independently from other sources. Especially in the today's environment of flat or even declining budgets ESA has to ensure the value of the contributions coming from their member states. The paper presents a software tool developed by the Cost Analysis Division of ESTEC/ESA, which fits exactly the need for precise and retracable cost estimates for space business projects and components. As an introduction the driving needs and basic cost estimation techniques are presented. ECOM was conceived as a tool for independent price assessment and cost estimation. The gem within ECOM is the database, it contains historical data from ESA projects. The items are grouped in classes and the available data comprises the cost breakdown and the technical description, which are the main performance parameter, number of models, design status and beside the comments, also pictures are available. On the estimate part of ECOM it features all the well-known cost estimation techniques, like estimating using analogy, cost estimating relationship, parametric cost modelling, and includes links to commercial products (PCM, Price-H) as well. ECOM is capable of escalating for any given economical condition and any member state. To prepare reliable prize estimates, the cost analysts need the product tree, the work-package description, the technical description and the HW-matrix. The paper shows examples for the important steps of producing an estimate and is enhanced with authentical screen prints. ECOM is used by the Cost Analysis Division as an expert tool for professional cost estimation for space business projects.

  3. Inventory-driven costs.

    PubMed

    Callioni, Gianpaolo; de Montgros, Xavier; Slagmulder, Regine; Van Wassenhove, Luk N; Wright, Linda

    2005-03-01

    In the 199os, Hewlett-Packard's PC business was struggling to turn a dollar, despite the company's success in winning market share. By 1997, margins on its PCs were as thin as a silicon wafer, and some product lines hadn't turned a profit since 1993. The problem had everything to do with the PC industry's notoriously short product cycles and brutal product and component price deflation. A common rule of thumb was that the value of a fully assembled PC decreased 1% a week. In such an environment, inventory costs become critical. But not just the inventory costs companies traditionally track, HP found, after a thorough review of the problem. The standard "holding cost of inventory"--the capital and physical costs of inventory--accounted for only about 10% of HP's inventory costs. The greater risks, it turned out, resided in four other, essentially hidden costs, which stemmed from mismatches between demand and supply: Component devaluation costs for components still held in production; Price protection costs incurred when product prices drop on the goods distributors still have on their shelves; Product return costs that have to be absorbed when distributors return and receive refunds on overstock items, and; Obsolescence costs for products still unsold when new models are introduced. By developing metrics to track those costs in a consistent way throughout the PC division, HP has found it can manage its supply chains with much more sophistication. Gone are the days of across-the-board measures such as,"Everyone must cut inventories by 20% by the end of the year," which usually resulted in a flurry of cookie-cutter lean production and just-in-time initiatives. Now, each product group is free to choose the supply chain configuration that best suits its needs. Other companies can follow HP's example.

  4. An Eye on Cost.

    ERIC Educational Resources Information Center

    Agron, Joe

    2000-01-01

    Presents the 11th annual residence hall construction report showing larger sized residence halls are costing less to construct. Statistics are presented of cost ranges for residence hall construction, the amenities being added to today's residence halls, and classroom- and science-building construction. (GR)

  5. Controlling Health Care Costs

    ERIC Educational Resources Information Center

    Dessoff, Alan

    2009-01-01

    This article examines issues on health care costs and describes measures taken by public districts to reduce spending. As in most companies in America, health plan designs in public districts are being changed to reflect higher out-of-pocket costs, such as higher deductibles on visits to providers, hospital stays, and prescription drugs. District…

  6. Curriculum Costs: Vocational Subjects.

    ERIC Educational Resources Information Center

    Cumming, C. E.

    To establish a definition of costs in education, a "concept map" is established to which inevitable questions of inclusion and exclusion can be addressed. A specific case, namely the costs of practical/vocational subjects, is then presented. It also includes a profile of benefits, since with regard to vocational education, much more than…

  7. Analyzing Bilingual Education Costs.

    ERIC Educational Resources Information Center

    Bernal, Joe J.

    This paper examines the particular problems involved in analyzing the costs of bilingual education and suggests that cost analysis of bilingual education requires a fundamentally different approach than that followed in other recent school finance studies. Focus of the discussion is the Intercultural Development Research Association's (IDRA)…

  8. Controlling Health Care Costs

    ERIC Educational Resources Information Center

    Dessoff, Alan

    2009-01-01

    This article examines issues on health care costs and describes measures taken by public districts to reduce spending. As in most companies in America, health plan designs in public districts are being changed to reflect higher out-of-pocket costs, such as higher deductibles on visits to providers, hospital stays, and prescription drugs. District…

  9. Grounds Maintenance Cost Report.

    ERIC Educational Resources Information Center

    Joice, Donald K.

    A grounds maintenance study was accomplished over the period of March 1965 through February 1966 to--(1) determine current grounds maintenance cost distribution; (2) provide basis for future grounds maintenance budgeting, and (3) provide basic data by which future landscape project designs can be developed to project or reduce maintenance costs.…

  10. Designing for Cost

    NASA Technical Reports Server (NTRS)

    Dean, Edwin B.; Unal, Resit

    1991-01-01

    Designing for cost is a state of mind. Of course, a lot of technical knowledge is required and the use of appropriate tools will improve the process. Unfortunately, the extensive use of weight based cost estimating relationships has generated a perception in the aerospace community that the primary way to reduce cost is to reduce weight. Wrong! Based upon an approximation of an industry accepted formula, the PRICE H (tm) production-production equation, Dean demonstrated theoretically that the optimal trajectory for cost reduction is predominantly in the direction of system complexity reduction, not system weight reduction. Thus the phrase "keep it simple" is a primary state of mind required for reducing cost throughout the design process.

  11. The Whole Cost of Libraries.

    ERIC Educational Resources Information Center

    Dunn, John A., Jr.; Martin, Murray S.

    1994-01-01

    Reviews costs involved in running libraries that are usually not considered. Topics discussed include building and maintenance costs, including insurance; growth costs, including print and/or electronic materials; physical expansion and staff; electronics; cost recovery, i.e., user fees; cost centers and overhead; user-related costs, including…

  12. Transmission line capital costs

    SciTech Connect

    Hughes, K.R.; Brown, D.R.

    1995-05-01

    The displacement or deferral of conventional AC transmission line installation is a key benefit associated with several technologies being developed with the support of the U.S. Department of Energy`s Office of Energy Management (OEM). Previous benefits assessments conducted within OEM have been based on significantly different assumptions for the average cost per mile of AC transmission line. In response to this uncertainty, an investigation of transmission line capital cost data was initiated. The objective of this study was to develop a database for preparing preliminary estimates of transmission line costs. An extensive search of potential data sources identified databases maintained by the Bonneville Power Administration (BPA) and the Western Area Power Administration (WAPA) as superior sources of transmission line cost data. The BPA and WAPA data were adjusted to a common basis and combined together. The composite database covers voltage levels from 13.8 to 765 W, with cost estimates for a given voltage level varying depending on conductor size, tower material type, tower frame type, and number of circuits. Reported transmission line costs vary significantly, even for a given voltage level. This can usually be explained by variation in the design factors noted above and variation in environmental and land (right-of-way) costs, which are extremely site-specific. Cost estimates prepared from the composite database were compared to cost data collected by the Federal Energy Regulatory Commission (FERC) for investor-owned utilities from across the United States. The comparison was hampered because the only design specifications included with the FERC data were voltage level and line length. Working within this limitation, the FERC data were not found to differ significantly from the composite database. Therefore, the composite database was judged to be a reasonable proxy for estimating national average costs.

  13. Cost Modeling for low-cost planetary missions

    NASA Technical Reports Server (NTRS)

    Kwan, Eric; Habib-Agahi, Hamid; Rosenberg, Leigh

    2005-01-01

    This presentation will provide an overview of the JPL parametric cost models used to estimate flight science spacecrafts and instruments. This material will emphasize the cost model approaches to estimate low-cost flight hardware, sensors, and instrumentation, and to perform cost-risk assessments. This presentation will also discuss JPL approaches to perform cost modeling and the methodologies and analyses used to capture low-cost vs. key cost drivers.

  14. Profitable capitation requires accurate costing.

    PubMed

    West, D A; Hicks, L L; Balas, E A; West, T D

    1996-01-01

    In the name of costing accuracy, nurses are asked to track inventory use on per treatment basis when more significant costs, such as general overhead and nursing salaries, are usually allocated to patients or treatments on an average cost basis. Accurate treatment costing and financial viability require analysis of all resources actually consumed in treatment delivery, including nursing services and inventory. More precise costing information enables more profitable decisions as is demonstrated by comparing the ratio-of-cost-to-treatment method (aggregate costing) with alternative activity-based costing methods (ABC). Nurses must participate in this costing process to assure that capitation bids are based upon accurate costs rather than simple averages.

  15. Mask cost and specification

    NASA Astrophysics Data System (ADS)

    Watanabe, Hisashi; Higashikawa, Iwao

    2003-12-01

    At the panel discussion of Photomask Japan 2003, we discussed about Mask cost and specification. The topics are (1) Mask price trend and its impact, (2) How to reduce the mask costs; solutions from a mask shop, mask writing tool and mask inspection tool 3) Partnering mask suppliers with mask users; reasonable mask specification and OPC strategies. The choice of DUV laser writer instead of e-beam writer is one solution for reduction of mask cost. The continuous improvement of e-beam writer and resist sensitivity for high throughput is another solution. The partnership between designer, EDA vender, mask maker and wafer lithographer becomes more important.

  16. Cost accounting for the radiologist.

    PubMed

    Gentili, Amilcare

    2014-05-01

    Cost accounting is the branch of managerial accounting that deals with the analysis of the costs of a product or service. This article reviews methods of classifying and allocating costs and relationships among costs, volume, and revenues. Radiology practices need to know the cost of a procedure or service to determine the selling price of a product, bid on contracts, analyze profitability, and facilitate cost control and cost reduction.

  17. The cost of dishonesty

    PubMed Central

    Viljugrein, H.

    1997-01-01

    The handicap principle states that stable biological signals must be honest and costly to produce. The cost of the signal should reflect the true quality of the signaller. Here, it is argued that honest signalling may be maintained although the used signals are not handicaps. A game theoretic model in the form of a game of signalling is presented: all the existing evolutionarily stable strategies (ESSs) are found. Honest and cheap signalling of male quality is shown to be evolutionarily stable if females divorce the mate if it turns out that he has cheated about his quality. However, for this ESS to apply, the cost of lost time must not be too great. The stability of the honest signalling is based on deceivers being prevented from spreading in the population because they suffer from a cost of divorce. Under some fairly strict conditions, a mixed polymorphism of dishonesty and honesty represents another possible ESS.

  18. Costs of Emergency Care

    MedlinePlus

    ... Campaigns ACEP Ads Published Letters/Articles Journalism Awards Social Media Health & Safety Tips Contact Us Site Body Left ... Campaigns ACEP Ads Published Letters/Articles Journalism Awards Social Media Health & Safety Tips Contact Us Main Content Costs ...

  19. Biosimilar Insulin and Costs

    PubMed Central

    Heinemann, Lutz

    2015-01-01

    The costs for insulin treatment are high, and the steady increase in the number of patients with diabetes on insulin presents a true challenge to health care systems. Therefore, all measures to lower these costs are welcomed by patients, physicians, and health care providers. The market introduction of biosimilar insulins presents an option to lower treatment costs as biosimilars are usually offered at a lower price than the originator product. However, the assumption that a drastic reduction in insulin prices will take place, as was observed with many generic drugs, is most probably not realistic. As the first biosimilar insulin has now been approved in the EU, this commentary discusses a number of aspects that are relevant when it comes to the potential cost reduction we will see with the use of biosimilar insulins. PMID:26350722

  20. Planning for Cost Effectiveness.

    ERIC Educational Resources Information Center

    Schlaebitz, William D.

    1984-01-01

    A heat pump life-cycle cost analysis is used to explain the technique. Items suggested for the life-cycle analysis approach include lighting, longer-life batteries, site maintenance, and retaining experts to inspect specific building components. (MLF)

  1. Planning for Cost Effectiveness.

    ERIC Educational Resources Information Center

    Schlaebitz, William D.

    1984-01-01

    A heat pump life-cycle cost analysis is used to explain the technique. Items suggested for the life-cycle analysis approach include lighting, longer-life batteries, site maintenance, and retaining experts to inspect specific building components. (MLF)

  2. [Costs of hand emergencies].

    PubMed

    Raimbeau, G

    2003-10-01

    In France at the present time, there is no comprehensive registry of hand injuries. Three types of occurrences; motor vehicle accidents, work accidents, and accidents incident to activities of daily living, are covered by different types of insurance. It is the individual insurance companies, payers of the indemnification, who maintain registries of these accidents. Statistics on work accidents are very detailed and consistent, but they are oriented toward risk management. The aggregate cost of traumatic injuries to the hand is not known. Only large financial institutions are equipped to determine appropriate preventive measures and to establish premium rates based on loss experience. In 2001, hand injuries accounted for 27% of work accidents causing loss of work of at least 1 day. About 29.8% of these work accidents caused permanent partial impairment. About 17.7% of total days lost and 18.2% of the total costs of permanent impairment were due to hand injuries. In the system of compensation for work accidents, there is a major difference in the cost according to the severity of the impairment. If the permanent impairment is equal to or less than 9%, a lump sum payment is made, but if the permanent impairment is over 9%, the worker receives regular payments for the rest of his life. In 2000, the average cost of a work injury with partial permanent impairment of over 9% was [symbol: see text] 85,405, while the average cost of a lump sum settlement was only [symbol: see text] 1479, a ratio of 57 to 1. The compensation costs represent 80% of the cost of work accidents, while the cost of treatment, including all providers and institutions, makes up only 20% of the cost. Compensation for sequelae of accidents in the course of daily life is new for the insurance companies, although these accidents are frequent and often cause significant repercussions in the professional lives of victims because of the loss of hand function. Provision of optimal treatment for these

  3. Hardwood sawmill downtime costs

    Treesearch

    Jan Wiedenbeck; Kyle Blackwell

    2003-01-01

    How time flies when you don't pay attention to it. With hardwood sawmill operating costs ranging from $4 to $25 per operating minute ($95/MBF to $335/MBF) and gross profit margins ranging from $0.10/BF to $0.35/BF, five extra minutes of downtime per day will cost a sawmill that produces an average of 20,000 BF per day (5 MMBF annually) between $21 and $73 per day...

  4. Implementing Replacement Cost Accounting

    DTIC Science & Technology

    1976-12-01

    the life of the assets used by the venture or for any changes in the buying power of money. Insuring that all transactions were recorded in an... make the use of such a system very difficult. It has not been widely supported as an alternative to historical costing . Exit values have been...previous research, procedures were proposed for making and reporting general price-level changes as supplemental information to historical cost financial

  5. Wakeflow analysis by cost

    NASA Technical Reports Server (NTRS)

    Anselmo, V. J.

    1981-01-01

    COST (Computerized Optical Scanning Tomography) is proposed for visualizing wakeflows of aircraft and wind-tunnel models. Operating very close to real time, COST hardware could be installed at airports to monitor turbulent flow trailing large aircraft, so that smaller aircraft could be directed to avoid turbulence. Real-time analysis of jet-engine exhaust plumes, to reduce pollution and optimize performance, is also possible.

  6. How much does curation cost?

    PubMed Central

    2016-01-01

    NIH administrators have recently expressed concerns about the cost of curation for biological databases. However, they did not articulate the exact costs of curation. Here we calculate the cost of biocuration of articles for the EcoCyc database as $219 per article over a 5-year period. That cost is 6–15% of the cost of open-access publication fees for publishing biomedical articles, and we estimate that cost is 0.088% of the cost of the overall research project that generated the experimental results. Thus, curation costs are small in an absolute sense, and represent a miniscule fraction of the cost of the research. PMID:27504008

  7. Costing the satellite power system

    NASA Technical Reports Server (NTRS)

    Hazelrigg, G. A., Jr.

    1978-01-01

    The paper presents a methodology for satellite power system costing, places approximate limits on the accuracy possible in cost estimates made at this time, and outlines the use of probabilistic cost information in support of the decision-making process. Reasons for using probabilistic costing or risk analysis procedures instead of standard deterministic costing procedures are considered. Components of cost, costing estimating relationships, grass roots costing, and risk analysis are discussed. Risk analysis using a Monte Carlo simulation model is used to estimate future costs.

  8. Tokamak reactor cost model based on STARFIRE/WILDCAT costing

    SciTech Connect

    Evans, K. Jr.

    1983-03-01

    A cost model is presented which is useful for survey and comparative studies of tokamak reactors. The model is heavily based on STARFIRE and WILDCAT costing guidelines, philosophies, and procedures and reproduces the costing for these devices quite accurately.

  9. Reducing Life-Cycle Costs.

    ERIC Educational Resources Information Center

    Roodvoets, David L.

    2003-01-01

    Presents factors to consider when determining roofing life-cycle costs, explaining that costs do not tell the whole story; discussing components that should go into the decision (cost, maintenance, energy use, and environmental costs); and concluding that important elements in reducing life-cycle costs include energy savings through increased…

  10. Reducing Life-Cycle Costs.

    ERIC Educational Resources Information Center

    Roodvoets, David L.

    2003-01-01

    Presents factors to consider when determining roofing life-cycle costs, explaining that costs do not tell the whole story; discussing components that should go into the decision (cost, maintenance, energy use, and environmental costs); and concluding that important elements in reducing life-cycle costs include energy savings through increased…

  11. Costs of predicting IDDM.

    PubMed

    Hahl, J; Simell, T; Ilonen, J; Knip, M; Simell, O

    1998-01-01

    Programmes aiming at prediction and prevention of insulin-dependent diabetes mellitus (IDDM), a multifactorial autoimmune disease, have been launched or are in the planning phase in several countries. We hypothesized that the costs of finding the correct target subjects for preventive interventions are likely to vary markedly according to the prediction strategy chosen. Average direct costs accruing in the Finnish IDDM Prediction and Prevention Project (DIPP) were analysed from the health care provider's viewpoint. The genetically targeted strategy included costs of assessing genetic IDDM susceptibility followed by measurement of marker(s) of islet autoimmunity in the susceptibility restricted population at 3 to 6-month intervals. In the pure immunological strategy markers of autoimmunity were repeatedly analysed in the entire population. The data were finally exposed to sensitivity analysis. The genetically targeted prediction strategy is cost-saving in the first year if autoimmune markers are analysed as frequently as under the DIPP project, and in all circumstances later. The 10-year direct costs per child are US$ 245 (present value $ 217, 5% discount rate) if the genetically targeted approach is used and $ 733 (present value $ 619) if the pure immunological strategy is chosen. In sensitivity analysis the 10-year costs (present value) per child of the genetically targeted strategy and of the pure immunological strategy varied from $ 152 to $ 241 and from $ 430 to $ 788, respectively. The genetically targeted IDDM prediction strategy is remarkably cost-saving as compared with the pure immunological strategy mainly because fewer subjects will need retesting during the follow-up.

  12. Orbits on a Concave Frictionless Surface

    DTIC Science & Technology

    2007-01-01

    ABSTRACT The equations of motion of a puck sliding frictionlessly inside a parabolic bowl can be straightforwardly deduced using the conservation laws...STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The equations of motion of a puck sliding...the complete code we wrote to solve and plot the motion of the puck using the commercial software program Maple™ for the case R 0 = 1 = V 0 , as

  13. General methodology: Costing, budgeting, and techniques for benefit-cost and cost-effectiveness analysis

    NASA Technical Reports Server (NTRS)

    Stretchberry, D. M.; Hein, G. F.

    1972-01-01

    The general concepts of costing, budgeting, and benefit-cost ratio and cost-effectiveness analysis are discussed. The three common methods of costing are presented. Budgeting distributions are discussed. The use of discounting procedures is outlined. The benefit-cost ratio and cost-effectiveness analysis is defined and their current application to NASA planning is pointed out. Specific practices and techniques are discussed, and actual costing and budgeting procedures are outlined. The recommended method of calculating benefit-cost ratios is described. A standardized method of cost-effectiveness analysis and long-range planning are also discussed.

  14. Factors Impacting Decommissioning Costs - 13576

    SciTech Connect

    Kim, Karen; McGrath, Richard

    2013-07-01

    The Electric Power Research Institute (EPRI) studied United States experience with decommissioning cost estimates and the factors that impact the actual cost of decommissioning projects. This study gathered available estimated and actual decommissioning costs from eight nuclear power plants in the United States to understand the major components of decommissioning costs. Major costs categories for decommissioning a nuclear power plant are removal costs, radioactive waste costs, staffing costs, and other costs. The technical factors that impact the costs were analyzed based on the plants' decommissioning experiences. Detailed cost breakdowns by major projects and other cost categories from actual power plant decommissioning experiences will be presented. Such information will be useful in planning future decommissioning and designing new plants. (authors)

  15. The Cost of Online Learning.

    ERIC Educational Resources Information Center

    Milshtein, Amy

    2001-01-01

    Examines development considerations and tips for controlling costs when a university decides to develop an online distance learning service. Use of the interactive Web Site for Determining Costs tool for unveiling hidden costs is highlighted. (GR)

  16. COSTS OF URBAN STORMWATER CONTROL

    EPA Science Inventory

    This paper presents information on the cost of stormwater pollution control facilities in urban areas, including collection, control, and treatment systems. Information on prior cost studies of control technologies and cost estimating models used in these studies was collected, r...

  17. Sweetener lowers costs

    SciTech Connect

    Muller, T.; Rosenstock, G.

    1983-10-01

    Mericat sweetening was used to get increased capacity needed by debottlenecking the FCCU at the Ruhr Refinery, Deutsche BP. A low conversion cost initiated the decision to adapt an existing copper chloride sweetener to Mericat but operating experience underscores the value of the choice because operating costs have been only 84% of design while anticipated capacity has been exceeded. Consequently, payout was accelerated to only about four months. Design specifications required that Light Cat Cracked Naphtha (LCCN) containing a maximum of 100 ppmw of mercaptan sulfur be sweetened to a maximum of 10 ppmw while caustic carryover sodium content not exceed 5 ppmw and that the sweetened LCCN meet Copper Strip No. 1 rating. Official tests based on runs with two different crude sources resulted in performance as shown in this paper. Operating costs of the copper chloride sweetening system before conversion and the Mericat system after conversion are also shown.

  18. Containing Health Care Costs

    PubMed Central

    Derzon, Robert A.

    1980-01-01

    As the federal government shifted from its traditional roles in health to the payment for personal health care, the relationship between public and private sectors has deteriorated. Today federal and state revenue funds and trusts are the largest purchasers of services from a predominantly private health system. This financing or “gap-filling” role is essential; so too is the purchaser's concern for the costs and prices it must meet. The cost per person for personal health care in 1980 is expected to average $950, triple for the aged. Hospital costs vary considerably and inexplicably among states; California residents, for example, spend 50 percent more per year for hospital care than do state of Washington residents. The failure of each sector to understand the other is potentially damaging to the parties and to patients. First, and most important, differences can and must be moderated through definite changes in the attitudes of the protagonists. PMID:6770551

  19. Technology and healthcare costs

    PubMed Central

    Kumar, R Krishna

    2011-01-01

    Medicine in the 21st century is increasingly dependent on technology. Unlike in many other areas, the cost of medical technology is not declining and its increasing use contributes to the spiraling healthcare costs. Many medical professionals equate progress in medicine to increasing use of sophisticated technology that is often expensive and beyond the reach of the average citizen. Pediatric heart care is very technology-intensive and therefore very expensive and beyond the reach of the vast majority of children in the developing world. There is an urgent need to address this situation through development and use of appropriate technology in accordance with the needs and priorities of the society. A number of simple and inexpensive quality measures that have the potential of improving outcomes substantially without the need for expensive equipment should be instituted before embracing high-end technology. Innovations to reduce costs that are commonly used in limited resource environments should be tested systematically. PMID:21677816

  20. Underestimation of Project Costs

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2015-01-01

    Large projects almost always exceed their budgets. Estimating cost is difficult and estimated costs are usually too low. Three different reasons are suggested: bad luck, overoptimism, and deliberate underestimation. Project management can usually point to project difficulty and complexity, technical uncertainty, stakeholder conflicts, scope changes, unforeseen events, and other not really unpredictable bad luck. Project planning is usually over-optimistic, so the likelihood and impact of bad luck is systematically underestimated. Project plans reflect optimism and hope for success in a supposedly unique new effort rather than rational expectations based on historical data. Past project problems are claimed to be irrelevant because "This time it's different." Some bad luck is inevitable and reasonable optimism is understandable, but deliberate deception must be condemned. In a competitive environment, project planners and advocates often deliberately underestimate costs to help gain project approval and funding. Project benefits, cost savings, and probability of success are exaggerated and key risks ignored. Project advocates have incentives to distort information and conceal difficulties from project approvers. One naively suggested cure is more openness, honesty, and group adherence to shared overall goals. A more realistic alternative is threatening overrun projects with cancellation. Neither approach seems to solve the problem. A better method to avoid the delusions of over-optimism and the deceptions of biased advocacy is to base the project cost estimate on the actual costs of a large group of similar projects. Over optimism and deception can continue beyond the planning phase and into project execution. Hard milestones based on verified tests and demonstrations can provide a reality check.

  1. Drilling cost-cutting

    SciTech Connect

    Capuano, L.E. Jr.

    1996-12-31

    This presentation by Louis E. Capuano, Jr., President, ThermaSource, Inc., discusses cost-cutting in the drilling phase of geothermal energy exploration and production. All aspects of a geothermal project including the drilling must be streamlined to make it viable and commercial. If production could be maximized from each well, there would be a reduction in drilling costs. This could be achieved in several ways, including big hole and multi-hole completion, directional drilling, better knowledge of the resource and where to penetrate, etc.

  2. Low Cost, Durable Seal

    SciTech Connect

    Roberts, George; Parsons, Jason; Friedman, Jake

    2010-12-17

    Seal durability is critical to achieving the 2010 DOE operational life goals for both stationary and transportation PEM fuel cell stacks. The seal material must be chemically and mechanically stable in an environment consisting of aggressive operating temperatures, humidified gases, and acidic membranes. The seal must also be producible at low cost. Currentlyused seal materials do not meet all these requirements. This project developed and demonstrated a high consistency hydrocarbon rubber seal material that was able to meet the DOE technical and cost targets. Significant emphasis was placed on characterization of the material and full scale molding demonstrations.

  3. Cost efficient command management

    NASA Technical Reports Server (NTRS)

    Brandt, Theresa; Murphy, C. W.; Kuntz, Jon; Barlett, Tom

    1996-01-01

    The design and implementation of a command management system (CMS) for a NASA control center, is described. The technology innovations implemented in the CMS provide the infrastructure required for operations cost reduction and future development cost reduction through increased operational efficiency and reuse in future missions. The command management design facilitates error-free operations which enables the automation of the routine control center functions and allows for the distribution of scheduling responsibility to the instrument teams. The reusable system was developed using object oriented methodologies.

  4. Cost Validation Using PRICE H

    NASA Technical Reports Server (NTRS)

    Jack, John; Kwan, Eric; Wood, Milana

    2011-01-01

    PRICE H was introduced into the JPL cost estimation tool set circa 2003. It became more available at JPL when IPAO funded the NASA-wide site license for all NASA centers. PRICE H was mainly used as one of the cost tools to validate proposal grassroots cost estimates. Program offices at JPL view PRICE H as an additional crosscheck to Team X (JPL Concurrent Engineering Design Center) estimates. PRICE H became widely accepted ca, 2007 at JPL when the program offices moved away from grassroots cost estimation for Step 1 proposals. PRICE H is now one of the key cost tools used for cost validation, cost trades, and independent cost estimates.

  5. Cost Validation Using PRICE H

    NASA Technical Reports Server (NTRS)

    Jack, John; Kwan, Eric; Wood, Milana

    2011-01-01

    PRICE H was introduced into the JPL cost estimation tool set circa 2003. It became more available at JPL when IPAO funded the NASA-wide site license for all NASA centers. PRICE H was mainly used as one of the cost tools to validate proposal grassroots cost estimates. Program offices at JPL view PRICE H as an additional crosscheck to Team X (JPL Concurrent Engineering Design Center) estimates. PRICE H became widely accepted ca, 2007 at JPL when the program offices moved away from grassroots cost estimation for Step 1 proposals. PRICE H is now one of the key cost tools used for cost validation, cost trades, and independent cost estimates.

  6. Turbulence induces metabolically costly behaviors and inhibits food capture in oyster larvae, causing net energy loss.

    PubMed

    Fuchs, Heidi L; Specht, Jaclyn A; Adams, Diane K; Christman, Adam J

    2017-10-01

    Planktotrophic invertebrate larvae require energy to develop, disperse and settle successfully, and it is unknown how their energetics are impacted by turbulence. Ciliated larvae gain metabolic energy from their phytoplankton food to offset the energetic costs of growth, development and ciliary activity for swimming and feeding. Turbulence may affect the energetic balance by inducing behaviors that alter the metabolic costs and efficiency of swimming, by raising the encounter rate with food particles and by inhibiting food capture. We used experiments and an empirical model to quantify the net rate of energy gain, swimming efficiency and food capture efficiency for eyed oyster larvae (Crassostrea virginica) in turbulence. At dissipation rates representative of coastal waters, larvae lost energy even when food concentrations were very high. Both feeding activity and turbulence-induced behaviors incurred high metabolic costs. Swimming efficiency was concave up versus dissipation rate, suggesting that ciliary activity for food handling became more costly while swimming became more efficient with turbulence intensity. Though counter-intuitive, swimming may have become more efficient in turbulence because vorticity-induced rotation caused larvae to swim more horizontally, which requires less effort than swimming vertically against the pull of gravity. Overall, however, larvae failed to offset high activity costs with food energy gains because turbulence reduced food capture efficiency more than it enhanced food encounter rates. Younger, smaller larvae may have some energetic advantages, but competent larvae would lose energy at turbulence intensities they experience frequently, suggesting that turbulence-induced starvation may account for much of oysters' high larval mortality. © 2017. Published by The Company of Biologists Ltd.

  7. 76 FR 53378 - Cost Accounting Standards: Accounting for Insurance Costs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... BUDGET Office of Federal Procurement Policy 48 CFR Part 9904 Cost Accounting Standards: Accounting for Insurance Costs AGENCY: Cost Accounting Standards Board (Board), Office of Federal Procurement Policy (OFPP... Office of Federal Procurement Policy (OFPP), Cost Accounting Standards (CAS) Board, is providing public...

  8. Costs and cost-effectiveness of periviable care.

    PubMed

    Caughey, Aaron B; Burchfield, David J

    2014-02-01

    With increasing concerns regarding rapidly expanding healthcare costs, cost-effectiveness analysis allows assessment of whether marginal gains from new technology are worth the increased costs. Particular methodologic issues related to cost and cost-effectiveness analysis in the area of neonatal and periviable care include how costs are estimated, such as the use of charges and whether long-term costs are included; the challenges of measuring utilities; and whether to use a maternal, neonatal, or dual perspective in such analyses. A number of studies over the past three decades have examined the costs and the cost-effectiveness of neonatal and periviable care. Broadly, while neonatal care is costly, it is also cost effective as it produces both life-years and quality-adjusted life-years (QALYs). However, as the gestational age of the neonate decreases, the costs increase and the cost-effectiveness threshold is harder to achieve. In the periviable range of gestational age (22-24 weeks of gestation), whether the care is cost effective is questionable and is dependent on the perspective. Understanding the methodology and salient issues of cost-effectiveness analysis is critical for researchers, editors, and clinicians to accurately interpret results of the growing body of cost-effectiveness studies related to the care of periviable pregnancies and neonates. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. 20 CFR 627.435 - Cost principles and allowable costs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Cost principles and allowable costs. 627.435... principles and allowable costs. (a) General. To be allowable, a cost shall be necessary and reasonable for... treatment through application of generally accepted accounting principles appropriate to the JTPA program...

  10. [Costing nuclear medicine diagnostic procedures].

    PubMed

    Markou, Pavlos

    2005-01-01

    To the Editor: Referring to a recent special report about the cost analysis of twenty-nine nuclear medicine procedures, I would like to clarify some basic aspects for determining costs of nuclear medicine procedure with various costing methodologies. Activity Based Costing (ABC) method, is a new approach in imaging services costing that can provide the most accurate cost data, but is difficult to perform in nuclear medicine diagnostic procedures. That is because ABC requires determining and analyzing all direct and indirect costs of each procedure, according all its activities. Traditional costing methods, like those for estimating incomes and expenses per procedure or fixed and variable costs per procedure, which are widely used in break-even point analysis and the method of ratio-of-costs-to-charges per procedure may be easily performed in nuclear medicine departments, to evaluate the variability and differences between costs and reimbursement - charges.

  11. Manned Mars mission cost estimate

    NASA Technical Reports Server (NTRS)

    Hamaker, Joseph; Smith, Keith

    1986-01-01

    The potential costs of several options of a manned Mars mission are examined. A cost estimating methodology based primarily on existing Marshall Space Flight Center (MSFC) parametric cost models is summarized. These models include the MSFC Space Station Cost Model and the MSFC Launch Vehicle Cost Model as well as other modes and techniques. The ground rules and assumptions of the cost estimating methodology are discussed and cost estimates presented for six potential mission options which were studied. The estimated manned Mars mission costs are compared to the cost of the somewhat analogous Apollo Program cost after normalizing the Apollo cost to the environment and ground rules of the manned Mars missions. It is concluded that a manned Mars mission, as currently defined, could be accomplished for under $30 billion in 1985 dollars excluding launch vehicle development and mission operations.

  12. Alignment-Insensitive Lower-Cost Telescope Architecture

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee; Hagopian, John; Dean, Bruce; Howard, Joe

    2008-01-01

    This architecture features an active wavefront sensing and control scheme along with methods for measuring the relative positions of the primary to aft optics, such as the secondary mirror, and should enable larger and cheaper telescope architectures needed for future applications. A wavefront source/sensor is placed at the center of curvature of the primary mirror. The system provides continuous light onto a primary mirror that is retro-reflected onto itself. This allows the wavefront controller to constantly update the positions of the primary mirror segments (or deformable mirror actuators). Another function of this innovation involves using a concave mirror on the back of the secondary mirror (or other aft optic) that has the same center-of-curvature location (in defocus) as the primary mirror. The two return beams can be aligned next to each other on a detector, or radially on top of each other. This provides a means with which to measure the relative position of the primary to the secondary (or other aft optics), thus allowing for the removal of misalignment of the center-of-curvature source/sensor (meaning it doesn't need precision placement) and also provides a means with which to monitor the relative alignment over time. This innovation does not require extremely good thermal stability on the primary mirror and can thus be used in any thermal environment and with cheaper materials. In addition to this, the architecture lets one phase (or align) the primary mirror independent of whether a star or scene is in the field. The segmented, spherical primary allows for cost-effective three-meter class (e.g. Midex and Discovery) missions as well as enabling 30-meter telescope solutions that can be manufactured in a reasonable amount of time. The continuous wavefront sensing and control architecture enables missions for low-Earth-orbit.

  13. MEOSAR Cost Escalation Risk

    DTIC Science & Technology

    2014-02-25

    Defence Research and Development Canada Recherche et développement pour la défense Canada DRDC-RDDC-2014-L Produced for Peter Iburg, CMA, Senior ......SME’s sensitivity analysis of their cost estimates. Senior project management’s input provides the majority opinion in the base estimates while DCostS’s

  14. Costing climate change

    NASA Astrophysics Data System (ADS)

    Reay, David S.

    2002-12-01

    Debate over how, when, and even whether man-made greenhouse-gas emissions should be controlled has grown in intensity even faster than the levels of greenhouse gas in our atmosphere. Many argue that the costs involved in reducing emissions outweigh the potential economic damage of human-induced climate change. Here, existing cost-benefit analyses of greenhouse-gas reduction policies are examined, with a view to establishing whether any such global reductions are currently worthwhile. Potential for, and cost of, cutting our own individual greenhouse-gas emissions is then assessed. I find that many abatement strategies are able to deliver significant emission reductions at little or no net cost. Additionally, I find that there is huge potential for individuals to simultaneously cut their own greenhouse-gas emissions and save money. I conclude that cuts in global greenhouse-gas emissions, such as those of the Kyoto Protocol, cannot be justifiably dismissed as posing too large an economic burden.

  15. Understanding Higher Education Costs

    ERIC Educational Resources Information Center

    Middaugh, Michael F.

    2005-01-01

    Public discussion of higher education costs frequently confuses price with expenditure. This article examines factors associated with increases in the sticker price of a college education and the expenditures incurred by institutions in delivering that education. The discussion suggests that while growth in college tuition is real, access to…

  16. Strategy Reduces Construction Costs.

    ERIC Educational Resources Information Center

    Flynn, Jim; Petters, Walt

    2000-01-01

    Reveals how a Florida school district had success when switching from a design-bid-build approach for school construction to a construction management (CM) at risk. The CM at risk process involving project delivery options, maximum price guarantees, and the school district's benefits in cost savings accrued are addressed. (GR)

  17. Costs and benefits

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Two models of cost benefit analysis are illustrated and the application of these models to assessing the economic scope of space applications programs was discussed. Four major areas cited as improvable through space derived information - food supply and distribution, energy sources, mineral reserves, and communication and navigation were - discussed. Specific illustrations are given for agriculture and maritime traffic.

  18. Cost Recovery Through Depreciation.

    ERIC Educational Resources Information Center

    Forrester, Robert T.; Wesolowski, Leonard V.

    1983-01-01

    The approach of adopting depreciation rather than use allowance in order to recover more accurately the cost of college buildings and equipment used on federal projects is considered. It is suggested that depreciation will offer most colleges and universities a higher annual recovery rate, and an opportunity for better facilities planning. For…

  19. Cutting Transportation Costs.

    ERIC Educational Resources Information Center

    Lewis, Barbara

    1982-01-01

    Beginning on the front cover, this article tells how school districts are reducing their transportation costs. Particularly effective measures include the use of computers for bus maintenance and scheduling, school board ownership of buses, and the conversion of gasoline-powered buses to alternative fuels. (Author/MLF)

  20. Cost Effective Prototyping

    NASA Technical Reports Server (NTRS)

    Wickman, Jerry L.; Kundu, Nikhil K.

    1996-01-01

    This laboratory exercise seeks to develop a cost effective prototype development. The exercise has the potential of linking part design, CAD, mold development, quality control, metrology, mold flow, materials testing, fixture design, automation, limited parts production and other issues as related to plastics manufacturing.

  1. Cutting Transportation Costs.

    ERIC Educational Resources Information Center

    Lewis, Barbara

    1982-01-01

    Beginning on the front cover, this article tells how school districts are reducing their transportation costs. Particularly effective measures include the use of computers for bus maintenance and scheduling, school board ownership of buses, and the conversion of gasoline-powered buses to alternative fuels. (Author/MLF)

  2. Help with housing costs.

    PubMed

    Moore, Alison

    2017-06-21

    Nurses working in the London area have benefited from a London 'weighting' for as long as many can remember. It can be the difference between being able to live and work in the capital and being forced to move elsewhere by the high cost of housing.

  3. Student Housing Cost Study.

    ERIC Educational Resources Information Center

    California Univ., Berkeley. Univ. Residential Building System.

    Target costs for the University Residential Building System (URBS) Project of the University of California are presented. Findings depict the effectiveness of building design and material applications and should be useful in guiding future student housing design work, whether the design utilizes the URBS system or not. Ten recently constructed…

  4. Covering Construction Costs.

    ERIC Educational Resources Information Center

    Hardy, Lawrence

    1997-01-01

    A 1996 U.S. General Accounting Office report indicates one-third of the nation's schools need $111 billion worth of repairs or partial replacement. Local school districts cannot keep up with enrollment increases or construction costs and will receive little help from federal or state governments. Capital improvement funding inequities are heating…

  5. Heliostat cost reduction study.

    SciTech Connect

    Jones, Scott A.; Lumia, Ronald. (University of New Mexico, Albuquerque, NM); Davenport, Roger (Science Applications International Corporation, San Diego, CA); Thomas, Robert C. (Advanced Thermal Systems, Centennial, CO); Gorman, David; Kolb, Gregory J.; Donnelly, Matthew W.

    2007-06-01

    Power towers are capable of producing solar-generated electricity and hydrogen on a large scale. Heliostats are the most important cost element of a solar power tower plant. Since they constitute {approx} 50% of the capital cost of the plant it is important to reduce heliostat cost as much as possible to improve the economic performance of power towers. In this study we evaluate current heliostat technology and estimate a price of $126/m{sup 2} given year-2006 materials and labor costs for a deployment of {approx}600 MW of power towers per year. This 2006 price yields electricity at $0.067/kWh and hydrogen at $3.20/kg. We propose research and development that should ultimately lead to a price as low as $90/m{sup 2}, which equates to $0.056/kWh and $2.75/kg H{sup 2}. Approximately 30 heliostat and manufacturing experts from the United States, Europe, and Australia contributed to the content of this report during two separate workshops conducted at the National Solar Thermal Test Facility.

  6. The Costs of Frontloading.

    ERIC Educational Resources Information Center

    Brinkman, Paul T.; Jones, Dennis P.

    The costs of directing additional instructional resources to lower-division instruction is assessed. "Frontloading," or directing additional resources toward lower-division students, was recommended by a national study group because first- and second-year students are frequently taught by junior instructors in large classes in which they…

  7. Cost Effective Prototyping

    NASA Technical Reports Server (NTRS)

    Wickman, Jerry L.; Kundu, Nikhil K.

    1996-01-01

    This laboratory exercise seeks to develop a cost effective prototype development. The exercise has the potential of linking part design, CAD, mold development, quality control, metrology, mold flow, materials testing, fixture design, automation, limited parts production and other issues as related to plastics manufacturing.

  8. Covering Construction Costs.

    ERIC Educational Resources Information Center

    Hardy, Lawrence

    1997-01-01

    A 1996 U.S. General Accounting Office report indicates one-third of the nation's schools need $111 billion worth of repairs or partial replacement. Local school districts cannot keep up with enrollment increases or construction costs and will receive little help from federal or state governments. Capital improvement funding inequities are heating…

  9. Opportunity Cost: A Reply

    ERIC Educational Resources Information Center

    Parkin, Michael

    2016-01-01

    The author's objective for this reply in reexamining opportunity cost was to draw attention to two conflicting definitions of the concept in current use and to argue the case for dropping one of them. The comments of Daniel Arce, Rod O'Donnell, and Daniel Stone might be read as demonstration that the author has failed on both counts. Such a…

  10. Opportunity Cost: A Reply

    ERIC Educational Resources Information Center

    Parkin, Michael

    2016-01-01

    The author's objective for this reply in reexamining opportunity cost was to draw attention to two conflicting definitions of the concept in current use and to argue the case for dropping one of them. The comments of Daniel Arce, Rod O'Donnell, and Daniel Stone might be read as demonstration that the author has failed on both counts. Such a…

  11. Measuring Retirees' Living Costs.

    ERIC Educational Resources Information Center

    Lamale, Helen H.

    1978-01-01

    The author evaluates the Consumer Price Index (CPI) used by the Bureau of Labor Statistics (BLS) to make cost-of-living adjustments to retirement benefits and considers the need for a separate retiree index. Stating that the CPI has underestimated inflation's impact on retirees, she recommends revised BLS retiree budgets. (MF)

  12. Cost Is Not Everything.

    ERIC Educational Resources Information Center

    Clement, Russell T.

    1985-01-01

    Reports results of survey of 21 smaller to medium-sized (50,000-200,000 volumes) libraries which was conducted to determine factors used to make selection decisions in purchase of automated turnkey systems from established vendors. Factors examined include costs, software, hardware, and vendors for parts A (actual experience) and B (hypothetical…

  13. Curbing Workers' Comp Costs.

    ERIC Educational Resources Information Center

    Deeb, William S.

    1998-01-01

    An actuarial study revealed that Pasadena Schools had an unfunded worker's compensation liability of over $10 million and 400 open claims. Advised to implement strong cost-containment measures (an early return-to-work program) and equally strong accountability measures (strict performance guides and safe work practices), the district achieved…

  14. Collaborating To Cut Costs.

    ERIC Educational Resources Information Center

    Strosnider, Kim

    1998-01-01

    Private colleges across the country are collaborating to cut costs, streamline services, and increase efficiency. An ambitious Ohio project, involving 35 colleges, to redesign business operations hopes to save $20-25 million. Other efforts include joint classes using interactive television, shared library resources, cross-registration, jointly…

  15. Educational Costs and Productivity.

    ERIC Educational Resources Information Center

    Hallak, Jacques, Comp.

    This seminar focused on costs and productivity as they are defined within both education and economics. Some topics that received special attention were: definition problems, estimating methods, analysis methods, existing research results, and examples of improvement in educational efficiency. The document groups seminar papers under (1) general…

  16. Cost Realism Handbook for Assuring More Realistic Contractor Cost Proposals

    DTIC Science & Technology

    1985-05-01

    realism. Solicitation: Specify cost realism in addition ,:) Government estimated cost as cost evaluation sub- - ieria in the solicitation and specify the...Analogy techniques involve extrapolations from actual costs for similar systems. Other techniques may include the use of industry wide factors. Parametric...of sources (e.g., actual costs for similar systems and industry wide factors) may be used to supplement the estimates based on specific contractor

  17. Tapping Transaction Costs to Forecast Acquisition Cost Breaches

    DTIC Science & Technology

    2016-01-01

    Government Accountability Office, active MDAPs in Fiscal Year (FY) 2011 collectively experienced a cost growth of $74.4 billion (Sullivan, 2011). The...measured to the current baseline. Nunn-McCurdy cost threshold breaches are based on original cost esti- mates for PAUC and APUC at project completion...In the case of a program that has rebaselined, cost threshold breaches are also based on the current (i.e., rebaselined) cost estimate for PAUC and

  18. Estimating decommissioning costs: The 1994 YNPS decommissioning cost study

    SciTech Connect

    Szymczak, W.J.

    1994-12-31

    Early this year, Yankee Atomic Electric Company began developing a revised decommissioning cost estimate for the Yankee Nuclear Power Station (YNPS) to provide a basis for detailed decommissioning planning and to reflect slow progress in siting low-level waste (LLW) and spent-nuclear-fuel disposal facilities. The revision also reflects the need to change from a cost estimate that focuses on overall costs to a cost estimate that is sufficiently detailed to implement decommissioning and identify the final cost of decommissioning.

  19. Antimicrobial stewardship programs - cost-minimizing or cost-effective?

    PubMed

    You, Joyce

    2015-02-01

    Antimicrobial stewardship programs (ASPs) are aimed to improve patient care and health care outcomes. It is encouraging to find ASP interventions to be cost-saving in many cost-minimization analyses in literature. Nevertheless, the cost-effectiveness of ASP interventions, measured in cost per quality-adjusted life-years, is less well-established. This Editorial aims to explore the barriers in assessing clinical effectiveness of ASPs and provide suggestions to conduct cost-effectiveness analysis of ASPs.

  20. The Concave Shape of the Forced Expiratory Flow-Volume Curve in 3 Seconds Is a Practical Surrogate of FEV1/FVC for the Diagnosis of Airway Limitation in Inadequate Spirometry.

    PubMed

    Li, Hao; Liu, Chunhong; Zhang, Yi; Xiao, Wei

    2017-03-01

    Spirometry is important for the differential diagnosis of dyspnea. However, some patients cannot exhale for ≥6 s to achieve the American Thoracic Society/European Respiratory Society criteria. The aim of this study was to demonstrate the reliability of a new parameter that quantifies the degree of concavity in the first 3 s to define airway limitation as a surrogate for the FEV1/FVC. Four hundred spirometry test results were selected through complete random sampling. The new parameter, termed the AUC3/AT3, was calculated as the area under the descending limb of the expiratory flow-volume curve before the end of the first 3 s (AUC3) divided by the area of the triangle before the end of the first 3 s (AT3). The AUC3/AT3 was compared with the FEV1/FVC using Pearson's correlation analysis. The level of agreement between the AUC3/AT3 and the FEV1/FVC in the detection of airway obstruction was analyzed using the kappa statistic. We also compared the diagnostic accuracy of the new index with that of the FEV1/forced expiratory volume in the first 3 s (FEV3). There was a strong correlation (r = 0.88, P < .001) between the AUC3/AT3 and the FEV1/FVC. There was also strong agreement between the AUC3/AT3 and the FEV1/FVC in the detection of obstruction with kappa indices of 0.72 (Global Initiative for Chronic Obstructive Lung Disease [GOLD] criterion) and 0.67 (lower limit of normal criterion), and these values were greater than those obtained for the FEV1/FEV3. The AUC3/AT3 also exhibited acceptable sensitivity, specificity, positive predictive value, and negative predictive value. The diagnostic accuracies of the AUC3/AT3 were 86.3% (GOLD criterion) and 83.8% (lower limit of normal criterion), which were greater than the 76.0 and 74.0% obtained for the FEV1/FEV3, respectively. The AUC3/AT3 can be utilized as a surrogate parameter for the FEV1/FVC when patients cannot complete a 6-s expiratory effort. Additionally, the performance of this index is better than that of the FEV

  1. Cost Accounting for Decision Makers.

    ERIC Educational Resources Information Center

    Kaneklides, Ann L.

    1985-01-01

    Underscores the importance of informed decision making through accurate anticipation of cost incurrence in light of changing economic and environmental conditions. Explains the concepts of cost accounting, full allocation of costs, the selection of an allocation base, the allocation of indirect costs, depreciation, and implications for community…

  2. Acquisition Cost/Price Estimating

    DTIC Science & Technology

    1981-01-01

    SYSTEMS, RECOMMENDING COST COALS FOR THOSE SYSTEMS, AND VALIDATING THOSE ESTIMATES THROUGH INDEPENDENT COSTING METHODS. INSTRUMENTS THROUGH WHICH SYSTEM...REVIEW AND VALIDATION, (3) RESEARCH AND METHODOLOGY AND (4) DATA ANALYSIS. THESE FUNCTIONAL THRUSTS ARE IN TURN FOCUSED TO ESTIMATING AND ANALISIS ...ANALYSIS OF COST ISSUES -- TO PROVIDE CONSISTENCY AND COMPLETENESS OF ESTIMATES PREPARED BY OTHER FUNCTIONAL ACTIVITIES. MANAGERIAL 1. COST ANALISIS HAS

  3. Variations in hospital administrative costs.

    PubMed

    McKay, Niccie L; Lemak, Christy Harris; Lovett, Annesha

    2008-01-01

    Administrative costs in hospitals are substantial and can have a major effect on performance. Despite this fact, not much research has been done to better understand such costs. This study examined variations in hospital administrative costs using a data set of acute care hospitals in Florida over the period 2000 through 2004. Results indicated that inflation-adjusted total administrative costs increased from about $22 million to $28 million on average over this time period. However, the percentage of total operating costs devoted to administrative costs was quite stable over the period, averaging approximately 23 percent in each of the five years. Compared with those in rural areas, urban hospitals on average had higher administrative costs per adjusted admission but lower administrative costs as a percentage of total operating costs. Hospital administrative costs also differed by ownership: For-profit hospitals on average had higher administrative costs per adjusted admission than not-for-profit and government hospitals, but administrative costs as a percentage of total operating costs were highest for for-profit hospitals and lowest for not-for-profit hospitals, with government hospitals falling in the middle. For bed size, administrative costs as a percentage of total operating costs were highest for the smallest hospitals. Results of this study will be useful to healthcare managers searching for ways to reduce unnecessary administrative costs while continuing to maintain the level of administrative activities required for the provision of safe, effective, high-quality care.

  4. Elements of Designing for Cost

    NASA Technical Reports Server (NTRS)

    Dean, Edwin B.; Unal, Resit

    1992-01-01

    During recent history in the United States, government systems development has been performance driven. As a result, systems within a class have experienced exponentially increasing cost over time in fixed year dollars. Moreover, little emphasis has been placed on reducing cost. This paper defines designing for cost and presents several tools which, if used in the engineering process, offer the promise of reducing cost. Although other potential tools exist for designing for cost, this paper focuses on rules of thumb, quality function deployment, Taguchi methods, concurrent engineering, and activity based costing. Each of these tools has been demonstrated to reduce cost if used within the engineering process.

  5. Elements of designing for cost

    NASA Technical Reports Server (NTRS)

    Dean, Edwin B.; Unal, Resit

    1992-01-01

    During recent history in the United States, government systems development has been performance driven. As a result, systems within a class have experienced exponentially increasing cost over time in fixed year dollars. Moreover, little emphasis has been placed on reducing cost. This paper defines designing for cost and presents several tools which, if used in the engineering process, offer the promise of reducing cost. Although other potential tools exist for designing for cost, this paper focuses on rules of thumb, quality function deployment, Taguchi methods, concurrent engineering, and activity-based costing. Each of these tools has been demonstrated to reduce cost if used within the engineering process.

  6. Space station: Cost and benefits

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Costs for developing, producing, operating, and supporting the initial space station, a 4 to 8 man space station, and a 4 to 24 man space station are estimated and compared. These costs include contractor hardware; space station assembly and logistics flight costs; and payload support elements. Transportation system options examined include orbiter modules; standard and extended duration STS fights; reusable spacebased perigee kick motor OTV; and upper stages. Space station service charges assessed include crew hours; energy requirements; payload support module storage; pressurized port usage; and OTV service facility. Graphs show costs for science missions, space processing research, small communication satellites; large GEO transportation; OVT launch costs; DOD payload costs, and user costs.

  7. Containing revenue-cycle costs.

    PubMed

    Geer, Robert; Burton, Eric

    2003-04-01

    Healthcare organizations can achieve revenue-cycle improvement while maintaining optimum staffing levels by taking a three-step approach-developing a plan, measuring costs, and using benchmarks to measure performance. Planned cost reductions can be achieved without a negative impact on the organization. Cost-reduction strategies should look at purchased services, staffing, and the cost-to-collect ratio. Healthcare organizations should reach target performance levels before implementing a cost-reduction strategy.

  8. Equipment life cycle costs minimised.

    PubMed

    Kuligowski, Sharon

    2004-11-01

    With the cost of energy now a major component of building operating costs, NHS Trust managers increasingly focus on estimating total life cycle costs of equipment such as boiler room and heat, steam and incineration plant. "Life cycle costing" is a broad term and encompasses a wide range of techniques that take into account both initial and future costs as well as the savings of an investment over a period of time.

  9. Solar energy systems cost

    SciTech Connect

    Lavender, J.A.

    1980-01-01

    Five major areas of work currently being pursued in the United States in solar energy which will have a significant impact on the world's energy situation in the future are addressed. The five significant areas discussed include a technical description of several solar technologies, current and projected cost of the selected solar systems, and cost methodologies which are under development. In addition, sensitivity considerations which are unique to solar energy systems and end user applications are included. A total of six solar technologies - biomass, photovoltaics, wind, ocean thermal energy conversion (OTEC), solar thermal, and industrial process heat (IPH) have been included in a brief technical description to present the variety of systems and their techncial status. System schematics have been included of systems which have been constructed, are currently in the detail design and test stage of development, or are of a conceptual nature.

  10. The costs of compliance.

    PubMed

    Leeman, Eve

    2007-01-01

    While the many costs of noncompliance have frequently been reviewed, this article addresses some of the costs of compliance, to the detriment of patients, doctors, and the doctor-patient relationship, and to the benefit of the pharmaceutical companies. Some psychiatric history is reviewed to analyze why psychiatric practice has become so focused on making specific diagnoses and treating those with specific medicines, even as fewer than 50% of patients follow medical advice. Some evidence for specific drug treatments is presented, and the powerful effects of nonspecific therapies, usually dismissed as confounders, are explored. Lastly, an argument for collaboration rather than compliance is made, imploring physicians to tailor individual treatment to each patient, and encouraging patients to be active in their own care.

  11. Getting the cost right in cost-effectiveness analyses.

    PubMed

    Wolff, N; Helminiak, T W; Tebes, J K

    1997-06-01

    The authors examined different ways of measuring unit costs and how methodological assumptions can affect the magnitude of cost estimates and the ratio of treatment costs in comparative studies of mental health interventions. Four methodological choices may bias cost estimates: study perspective, definition of the opportunity cost of resources, cost allocation rules, and measurement of service units. Unit costs for outpatient services, individual therapy, and group therapy were calculated under different assumptions for a single community mental health center (CMHC). Using hypothetical service utilization profiles, the authors used the unit costs to calculate the costs of mental health treatments provided by two programs of the CMHC. The unit costs for an hour of outpatient services ranged from $108 to $538. The unit costs for an hour of therapy varied by 156%; unit costs were lowest if the management perspective was assumed and highest if the economist perspective was assumed. The ratio of the outpatient costs in the two treatment programs ranged from 0.6 to 1.8. The potential errors introduced by methodological choices can bias cost-effectiveness findings based on randomized control trials. These errors go undetected because crucial methodological information is not reported.

  12. Exploration cost-cutting

    SciTech Connect

    Huttrer, J.

    1996-12-31

    This presentation by Jerry Huttrer, President, Geothermal Management Company, discusses the general state of exploration in the geothermal industry today, and mentions some ways to economize and perhaps save costs of geothermal exploration in the future. He suggests an increased use of satellite imagery in the mapping of geothermal resources and the identification of hot spots. Also, coordinating with oil and gas exploration efforts, the efficiency of the exploration task could be optimized.

  13. Cost Index Flying

    DTIC Science & Technology

    2011-06-01

    learning how they computed their particular cost indexes. Next, primary data was gathered from the AMC Fuel Efficiency Office and AMC Finance...fighting forces in the world . Today, the Air Mobility Command (AMC) has been called on to execute its mission like never before. With budgets...of the 2 previous DoD fuel consumption, with aviation accounting for approximately 84% of the Air Force’s energy consumption, or about 50% of the

  14. Geothermal probabilistic cost study

    NASA Technical Reports Server (NTRS)

    Orren, L. H.; Ziman, G. M.; Jones, S. C.; Lee, T. K.; Noll, R.; Wilde, L.; Sadanand, V.

    1981-01-01

    A tool is presented to quantify the risks of geothermal projects, the Geothermal Probabilistic Cost Model (GPCM). The GPCM model was used to evaluate a geothermal reservoir for a binary-cycle electric plant at Heber, California. Three institutional aspects of the geothermal risk which can shift the risk among different agents was analyzed. The leasing of geothermal land, contracting between the producer and the user of the geothermal heat, and insurance against faulty performance were examined.

  15. Ammunition Cost Research Study

    DTIC Science & Technology

    1976-06-01

    and discarding sabot projectiles, as well as aluminum, telescoped, and combustible cartridge cases. 2. The general difficulty of fuze estimating...size in millimeters ■ Average annual production rate in thousands COMBUSTIBLE LnZ = 1.2865 + 0.01015 X where: Z ■ Estimated unit cost in FY 74...APT, and TPT) 2. LAP (Metal and combustible cartridge cased) 3. Cartridge Case (Steel, spiral wrap, brass, and combustible ) 4. Fuze Initial

  16. Geothermal probabilistic cost study

    NASA Astrophysics Data System (ADS)

    Orren, L. H.; Ziman, G. M.; Jones, S. C.; Lee, T. K.; Noll, R.; Wilde, L.; Sadanand, V.

    1981-08-01

    A tool is presented to quantify the risks of geothermal projects, the Geothermal Probabilistic Cost Model (GPCM). The GPCM model was used to evaluate a geothermal reservoir for a binary-cycle electric plant at Heber, California. Three institutional aspects of the geothermal risk which can shift the risk among different agents was analyzed. The leasing of geothermal land, contracting between the producer and the user of the geothermal heat, and insurance against faulty performance were examined.

  17. Integrated Cost Accounting System.

    DTIC Science & Technology

    1992-07-27

    few other companies. Harvard Business Review contained articles explaining the ideas behind the new costing methods and examples of applications...technical report. Peter Drucker in an article in Harvard Business Review ’carefully explains that accounting must change in response to the changes in...Kaplan in a Harvard Business Review article develop the idea of four levels of activities: facility sustaining activities; product-sustaining activities

  18. [Operating cost analysis of anaesthesia: activity based costing (ABC analysis)].

    PubMed

    Majstorović, Branislava M; Kastratović, Dragana A; Vučović, Dragan S; Milaković, Branko D; Miličić, Biljana R

    2011-01-01

    Cost of anaesthesiology represent defined measures to determine a precise profile of expenditure estimation of surgical treatment, which is important regarding planning of healthcare activities, prices and budget. In order to determine the actual value of anaestesiological services, we started with the analysis of activity based costing (ABC) analysis. Retrospectively, in 2005 and 2006, we estimated the direct costs of anestesiological services (salaries, drugs, supplying materials and other: analyses and equipment.) of the Institute of Anaesthesia and Resuscitation of the Clinical Centre of Serbia. The group included all anesthetized patients of both sexes and all ages. We compared direct costs with direct expenditure, "each cost object (service or unit)" of the Republican Healthcare Insurance. The Summary data of the Departments of Anaesthesia documented in the database of the Clinical Centre of Serbia. Numerical data were utilized and the numerical data were estimated and analyzed by computer programs Microsoft Office Excel 2003 and SPSS for Windows. We compared using the linear model of direct costs and unit costs of anaesthesiological services from the Costs List of the Republican Healthcare Insurance. Direct costs showed 40% of costs were spent on salaries, (32% on drugs and supplies, and 28% on other costs, such as analyses and equipment. The correlation of the direct costs of anaestesiological services showed a linear correlation with the unit costs of the Republican Healthcare Insurance. During surgery, costs of anaesthesia would increase by 10% the surgical treatment cost of patients. Regarding the actual costs of drugs and supplies, we do not see any possibility of costs reduction. Fixed elements of direct costs provide the possibility of rationalization of resources in anaesthesia.

  19. The costs of rape.

    PubMed

    Perilloux, Carin; Duntley, Joshua D; Buss, David M

    2012-10-01

    The current study examined costs experienced by victims of completed rape (n=49) and attempted sexual assault (n=91) using quantitative analyses of 13 domains: health, self-esteem, self-perceived attractiveness, self-perceived mate value, family relationships,work life, social life, social reputation, sexual reputation, desire to have sex, frequency of sex, enjoyment of sex, and long-term, committed relationships. Women also provided descriptive accounts of their experiences, and we used these to illustrate the costs in the victims' own words.Compared to victims of an attempted sexual assault, victims of a completed rape reported significantly more negative outcomes in 11 of the 13 domains. The most negatively affected domains were self-esteem, sexual reputation, frequency of sex, desire to have sex, and self-perceived mate value. Although victims of rape experienced more negative effects than victims of attempted sexual assault,both groups of victims reported negative effects in every domain.Discussion focuses on the implications of the differing degrees and patterns of the costs of attempted and completed sexual victimization.

  20. Proposed reliability cost model

    NASA Technical Reports Server (NTRS)

    Delionback, L. M.

    1973-01-01

    The research investigations which were involved in the study include: cost analysis/allocation, reliability and product assurance, forecasting methodology, systems analysis, and model-building. This is a classic example of an interdisciplinary problem, since the model-building requirements include the need for understanding and communication between technical disciplines on one hand, and the financial/accounting skill categories on the other. The systems approach is utilized within this context to establish a clearer and more objective relationship between reliability assurance and the subcategories (or subelements) that provide, or reenforce, the reliability assurance for a system. Subcategories are further subdivided as illustrated by a tree diagram. The reliability assurance elements can be seen to be potential alternative strategies, or approaches, depending on the specific goals/objectives of the trade studies. The scope was limited to the establishment of a proposed reliability cost-model format. The model format/approach is dependent upon the use of a series of subsystem-oriented CER's and sometimes possible CTR's, in devising a suitable cost-effective policy.

  1. Is empathy cost efficient?

    PubMed

    Book, H E

    1991-01-01

    In an attempt to constrain rising health-care costs, third-party payers are currently encouraging psychiatrists and other physicians to focus on the financial aspects of their treatment approaches. This paper has attempted to address the impact of this cost-efficient attitude on our empathy and by tracking the evolution of our health-care-delivery system since the turn of the century. I have described three overlapping phases: the humanist, the scientific, and the current corporate phase, and emphasized the importance or trivialization of an empathic practice-style associated with each stage. I have warned how the corporate delivery system, with its focus on cost constraints, may inhibit our capacity to be empathic by stimulating self-serving concerns about the corporation's monetary welfare and our own financial well-being. This unempathic stance may result in treatment being driven by financial factors that override clinically driven needs of the patient. At its extreme, this approach may render psychiatrists vulnerable for viewing patients as bad objects that deprive financially, and for countertransferentially retaliating against them through "warehousing" and abandonment.

  2. Cost-utility analysis.

    PubMed Central

    Robinson, R

    1993-01-01

    Decisions have to be made about allocating health resources. Currently the best economic evaluation method for doing this is cost-utility analysis. This compares the costs of different procedures with their outcomes measured in "utility based" units--that is, units that relate to a person's level of wellbeing. The most commonly used unit is the quality adjusted life year (QALY). QALYs are calculated by estimating the total life years gained from a procedure and weighting each year to reflect the quality of life in that year. To compare outcomes of different programmes the Rosser index is one measure that is widely used to assign quality of life scores to patients. Combined with a measure of life years gained from a procedure, this enables QALYs to be calculated and procedures ranked according to cost per QALY gained. In this article Ray Robinson explains the measures used and discusses how QALY league tables can be used to guide decisions on resource allocation. Images p862-a PMID:8401133

  3. Accounting for future costs in medical cost-effectiveness analysis.

    PubMed

    Meltzer, D

    1997-02-01

    Most medical cost-effectiveness analyses include future costs only for related illnesses, but this approach is controversial. This paper demonstrates that cost-effectiveness analysis is consistent with lifetime utility maximization only if it includes all future medical and non-medical expenditures. Estimates of the magnitude of these future costs suggest that they may substantially alter both the absolute and relative cost-effectiveness of medical interventions, particularly when an intervention increases length of life more than quality of life. In older populations, current methods overstate the cost-effectiveness of interventions which extend life compared to interventions which improve the quality of life.

  4. Modeling costs of plastics recycling

    SciTech Connect

    Not Available

    1993-10-01

    This article describes TCM, a computer spreadsheet technique to simulate process costs. In a technical cost model, cost is assigned to each unit operation in a process flow diagram. Costs are summarized corresponding to unit operations, each representing a single machine or station with an associated production rate. Each station is characterized by factors including number of laborers, equipment and tooling costs, and other investment and operating costs. Technical cost models can be used to: simulate costs of manufacturing; establish direct comparisons between material, process, and design alternatives; investigate the effect of changes in the process options on overall cost; identify limiting process steps and parameters; determine merits of specific process and design improvements.

  5. Costing bias in economic evaluations.

    PubMed

    Frappier, Julie; Tremblay, Gabriel; Charny, Mark; Cloutier, L Martin

    2015-01-01

    Determining the cost-effectiveness of healthcare interventions is key to the decision-making process in healthcare. Cost comparisons are used to demonstrate the economic value of treatment options, to evaluate the impact on the insurer budget, and are often used as a key criterion in treatment comparison and comparative effectiveness; however, little guidance is available to researchers for establishing the costing of clinical events and resource utilization. Different costing methods exist, and the choice of underlying assumptions appears to have a significant impact on the results of the costing analysis. This editorial describes the importance of the choice of the costing technique and it's potential impact on the relative cost of treatment options. This editorial also calls for a more efficient approach to healthcare intervention costing in order to ensure the use of consistent costing in the decision-making process.

  6. How much does curation cost?

    PubMed

    Karp, Peter D

    2016-01-01

    NIH administrators have recently expressed concerns about the cost of curation for biological databases. However, they did not articulate the exact costs of curation. Here we calculate the cost of biocuration of articles for the EcoCyc database as $219 per article over a 5-year period. That cost is 6-15% of the cost of open-access publication fees for publishing biomedical articles, and we estimate that cost is 0.088% of the cost of the overall research project that generated the experimental results. Thus, curation costs are small in an absolute sense, and represent a miniscule fraction of the cost of the research. © The Author(s) 2016. Published by Oxford University Press.

  7. LIFE Cost of Electricity, Capital and Operating Costs

    SciTech Connect

    Anklam, T

    2011-04-14

    Successful commercialization of fusion energy requires economic viability as well as technical and scientific feasibility. To assess economic viability, we have conducted a pre-conceptual level evaluation of LIFE economics. Unit costs are estimated from a combination of bottom-up costs estimates, working with representative vendors, and scaled results from previous studies of fission and fusion plants. An integrated process model of a LIFE power plant was developed to integrate and optimize unit costs and calculate top level metrics such as cost of electricity and power plant capital cost. The scope of this activity was the entire power plant site. Separately, a development program to deliver the required specialized equipment has been assembled. Results show that LIFE power plant cost of electricity and plant capital cost compare favorably to estimates for new-build LWR's, coal and gas - particularly if indicative costs of carbon capture and sequestration are accounted for.

  8. The cost of IT security.

    PubMed

    McMillan, Mac

    2015-04-01

    Breaches in data security have become commonplace in health care, making IT security a necessary cost for healthcare organizations. Organizations that do not invest proactively in IT security face a significant risk of incurring much greater costs from incidents involving compromised data security. Direct costs of security breaches include the costs of discovery, response, investigation, and notification and also can include state or federal penalties and costs of compliance with corrective action plans and resolution agreements. Hidden costs can include damage to brand, loss of consumer confidence, reduced HCAHPS scores, and--by extension--reduced value-based purchasing payments.

  9. Cataract, cost: curious questions.

    PubMed

    Moran, D J

    1999-02-01

    An investigation of the pricing of implantable prosthetic devices in Australia reveals some alarming practices. A governmental mechanism exists to prop up the pricing of 7500 listed devices to levels that are unacceptably high by world standards. Private hospitals and doctors are able, legally, to profit by marking up the cost of these devices from the market price to this artificially inflated price. Even the open market prices of implantable prosthetic items, such as intra-ocular lenses, are high by international standards. In a time of budgetary constraint for health spending and rapidly increasing use of these devices, these issues urgently need to be addressed in Australia.

  10. Low cost space.

    NASA Technical Reports Server (NTRS)

    Tischler, A. O.

    1973-01-01

    It is pointed out that a contradiction between boundless space and limited resources has put the space program in the distressing position of cutting good and worthy projects from its activities during this decade. One approach to ameliorate the situation is to increase the productivity of space activities by greater utilization of the equipment developed for its projects. The Space Shuttle constitutes the first big step in that direction. The reusable character of the Shuttle orbiter will cut operational costs by permitting recovery and reuse of payload equipment through routine round-trip operations to space.

  11. Cost Improvement Analysis

    DTIC Science & Technology

    1986-06-01

    aaencies to aid in estimating the cost of selected Government hardware items. Its application has been quite conspicuous ir airframe production where...O r.0 OCCO I0 C COO.. - - . g ** *.~~~~. . .* . . .a .a e . . r . . C.Ot . .~C -0~O0 ag g 88-etc tea -c- ss..-e r este ~¶¶~ n:s a::: 9--t Tie~ c. a...qudntLt,-i Oil the fol lowing: LUT TOTAL LAuOR HIOURS AVLRAGL LABUR HOURS LOT SIZE PER LOT FOR LUT 1 8 2312 289 2 16 2672 167 3 26 3120 120 4 32 3040 95 5

  12. Activity-Based Costing: A Cost Management Tool.

    ERIC Educational Resources Information Center

    Turk, Frederick J.

    1993-01-01

    In college and university administration, overhead costs are often charged to programs indiscriminately, whereas the support activities that underlie those costs remain unanalyzed. It is time for institutions to decrease ineffective use of resources. Activity-based management attributes costs more accurately and can improve efficiency. (MSE)

  13. Cost Benefit Model Development. Cost Benefit Study. Final Report.

    ERIC Educational Resources Information Center

    Marson, Arthur A.; And Others

    Through an analysis of the economic costs and benefits of five vocational-technical programs, it was shown that the benefits of a vocational-technical education outweigh the costs. Four programs showing greater benefits than costs were auto body (courses at two technical institutes), materials management, and electronic servicing. Clothing…

  14. 20 CFR 627.435 - Cost principles and allowable costs.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Cost principles and allowable costs. 627.435 Section 627.435 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR GENERAL... Administrative Law Judge, are unallowable. (g) Costs of travel and incidental expenses incurred by volunteers are...

  15. Cost Differential Analysis: Providing Data for Added Cost Funding

    ERIC Educational Resources Information Center

    Nystrom, Dennis C.; Hennessy, James V.

    1975-01-01

    A 1972-73 statewide study conducted in Illinois to develop a cost accounting system which facilitates cost differential ratios for secondary vocational education courses indicated that vocational programs are approximately twice as expensive as nonvocational. Specific cost elements identified in the study provided essential information regarding…

  16. Cost-Plus-Percentage-of-Costs in Government Contracts

    DTIC Science & Technology

    1984-09-01

    you estimate what this research would have cost if it had been accomplished under contract or if it had been done in-house *. - in terms of manpower...Prohibition Based on Cost Type Contracts . .. .. .. .. .. ... .81 Safeguards to Prevent CPPC Cost manipulations................82 * VII. COMPENSATION UNDER ...ILLEGAL CPPC CONTRACTS ... *... . . .. .. .. .. . 85 Plain Illegality Rule .. ..... . . . . 85 * Implied Contract Recovery Under the Tucker Act

  17. Costs in Perspective: Understanding Cost-Effectiveness Analysis.

    PubMed

    Detsky

    1996-01-01

    This paper covers five questions: (1) What is cost-effectiveness analysis;quest; (2) How can cost-effectiveness analysis help policymakers allocate scarce resources;quest; (3) What are misconceptions about the cost effectiveness of health care interventions;quest; (4) What is an attractive cost-effectiveness ratio;quest; (5) What is the relevance of cost effectiveness to clinicians? The cost side of the equation includes more than simply the cost of the intervention, but rather the cost of all of the downstream clinical events that occur with either therapeutic alternative. Cost-effectiveness analyses are used to help decisionmakers rank programs competing for scarce resources in order to achieve the following objective: to maximize the net health benefits derived from a fixed budget for a target population. A simple example is shown. Measured cost-effectiveness ratios for selected cardiovascular interventions are displayed. The systematic use of information on effectiveness and cost effectiveness should help those involved in setting policies to have a more rational basis for funding of new programs and discontinuation of funding for old programs. In Canadian health care it is important that we use this information to make room for innovations that are effective and efficient, and to remove funding from programs that are either known to be ineffective and costly or inefficient use of resources. More energy should be put toward generating the information necessary to make these kinds of decisions.

  18. Activity-Based Costing: A Cost Management Tool.

    ERIC Educational Resources Information Center

    Turk, Frederick J.

    1993-01-01

    In college and university administration, overhead costs are often charged to programs indiscriminately, whereas the support activities that underlie those costs remain unanalyzed. It is time for institutions to decrease ineffective use of resources. Activity-based management attributes costs more accurately and can improve efficiency. (MSE)

  19. Cost Estimates for Federal Student Loans: The Market Cost Debate

    ERIC Educational Resources Information Center

    Delisle, Jason

    2008-01-01

    In an ongoing debate about the relative costs of the federal government's direct and guaranteed student loan programs, some budget experts and private lenders have argued for the use of "market cost" estimates. They assert that official government cost estimates for federal student loans differ from what private entities would likely charge…

  20. Costing and cost analysis in randomized controlled trials: caveat emptor.

    PubMed

    Polsky, Daniel; Glick, Henry

    2009-01-01

    This article provides an overview of the central issues regarding cost valuation and analysis for a decision maker's evaluation of costing performed within randomized controlled trials (RCTs). Costing involves specific choices for valuation and analysis that involve trade-offs. Understanding these choices and their implications is necessary for proper evaluation of how costs are valued and analyzed within an RCT and cannot be assessed through a checklist of adherence to general principles. Resource costing, the most common method of costing, involves measuring medical service use in study case report forms and translating this use into a cost by multiplying the number of units of each medical service by price weights for those services. A choice must be made as to how detailed the measurement of resources will be. Micro-costing improves the specificity of the cost estimate, but it is often impractical to precisely measure resources at this level and the price weights for these micro-units may not be available. Gross-costing may be more practical, and price weights are often easier to find and are more reliable, but important resource differences between treatment groups may be lost in the bundling of resources. Price weights can either be nationally determined or centre specific, but the appropriate price weight will depend on perspective, convenience, completeness and accuracy. Identifying the resource types and the appropriate price weights for these resources are the essential elements to an accurate valuation of costs. Once medical services are valued, the resulting individual patient cost estimates must be analysed. The difference in the mean cost between treatment groups is the important summary statistic for cost-effectiveness analysis from both the budgetary and the social perspectives. The statistical challenges with cost data typically stem from its skewed distribution and the resulting possibility that the sample mean may be inefficient and possibly

  1. National Variation in Urethroplasty Cost and Predictors of Extreme Cost: A Cost Analysis with Policy Implications

    PubMed Central

    Harris, Catherine R.; Osterberg, E. Charles; Sanford, Thomas; Alwaal, Amjad; Gaither, Thomas W.; McAninch, Jack W.; McCulloch, Charles E.; Breyer, Benjamin N.

    2016-01-01

    Objective To determine which factors are associated with higher urethroplasty procedural costs and whether they have been increasing or decreasing over time. Identification of determinants of extreme costs may help reduce cost while maintaining quality. Materials and Methods We conducted a retrospective analysis using the 2001–2010 Healthcare Cost and Utilization Project - Nationwide Inpatient Sample (HCUP-NIS). The HCUP-NIS captures hospital charges which we converted to cost using the HCUP Cost-to-Charge Ratio. Log cost linear regression with sensitivity analysis was used to determine variables associated with increased costs. Extreme cost was defined as the top 20th percentile of expenditure, analyzed with logistic regression and expressed as Odds Ratios (OR). Results A total of 2298 urethroplasties were recorded in NIS over the study period. The median (interquartile range) calculated costs was $7321 ($5677–$10000). Patients with multiple comorbid conditions were associated with extreme costs (OR 1.56 95% CI 1.19–2.04, p=0.02) compared to patients with no comorbid disease. Inpatient complications raised the odds of extreme costs OR 3.2 CI 2.14–4.75, p<0.001). Graft urethroplasties were associated with extreme costs (OR 1.78 95% CI 1.2–2.64, p=0.005). Variation in patient age, race, hospital region, bed size, teaching status, payer type, and volume of urethroplasty cases were not associated with extremes of cost. Conclusion Cost variation for perioperative inpatient urethroplasty procedures is dependent on preoperative patient comorbidities, postoperative complications and surgical complexity related to graft usage. Procedural cost and cost variation are critical for understanding which aspects of care have the greatest impact on cost. PMID:27107626

  2. National Variation in Urethroplasty Cost and Predictors of Extreme Cost: A Cost Analysis With Policy Implications.

    PubMed

    Harris, Catherine R; Osterberg, E Charles; Sanford, Thomas; Alwaal, Amjad; Gaither, Thomas W; McAninch, Jack W; McCulloch, Charles E; Breyer, Benjamin N

    2016-08-01

    To determine which factors are associated with higher costs of urethroplasty procedure and whether these factors have been increasing over time. Identification of determinants of extreme costs may help reduce cost while maintaining quality. We conducted a retrospective analysis using the 2001-2010 Healthcare Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS). The HCUP-NIS captures hospital charges which we converted to cost using the HCUP cost-to-charge ratio. Log cost linear regression with sensitivity analysis was used to determine variables associated with increased costs. Extreme cost was defined as the top 20th percentile of expenditure, analyzed with logistic regression, and expressed as odds ratios (OR). A total of 2298 urethroplasties were recorded in NIS over the study period. The median (interquartile range) calculated cost was $7321 ($5677-$10,000). Patients with multiple comorbid conditions were associated with extreme costs [OR 1.56, 95% confidence interval (CI) 1.19-2.04, P = .02] compared with patients with no comorbid disease. Inpatient complications raised the odds of extreme costs (OR 3.2, CI 2.14-4.75, P <.001). Graft urethroplasties were associated with extreme costs (OR 1.78, 95% CI 1.2-2.64, P = .005). Variations in patient age, race, hospital region, bed size, teaching status, payor type, and volume of urethroplasty cases were not associated with extremes of cost. Cost variation for perioperative inpatient urethroplasty procedures is dependent on preoperative patient comorbidities, postoperative complications, and surgical complexity related to graft usage. Procedural cost and cost variation are critical for understanding which aspects of care have the greatest impact on cost. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Beyond managed costs.

    PubMed

    Savage, G T; Campbell, K S; Patman, T; Nunnelley, L L

    2000-01-01

    Managed care organizations (MCOs) face an uncertain future. While consolidation and price competition have expanded their market share, health care expenditures are expected to rise in the near future, and the cost containment premise--and promise--of MCOs is being threatened by mixed blessing and nonsupportive stakeholders. To shed light on MCOs' situation, we discuss four drivers for change in health management in the U.S.: technology, regulation, consumerism, and demographics. Using those four drivers, we then assess the various stakeholders in the industry through a competitive analysis and a stakeholder analysis. These analyses suggest that the munificence of the MCO business environment has significantly declined, especially among supplier and buyer stakeholders. Hence, MCOs cannot continue to manage health care costs alone as this will no longer generate sufficient support among buyer and supplier stakeholders. Instead, MCOs must tackle five critical health care issues by working closely with other stakeholders and also by learning what they can from innovative health care initiatives both inside and outside the United States.

  4. The cost of linearization

    NASA Astrophysics Data System (ADS)

    Morel, Danielle; Levy, William B.

    2006-03-01

    Information processing in the brain is metabolically expensive and energy usage by the different components of the nervous system is not well understood. In a continuing effort to explore the costs and constraints of information processing at the single neuron level, dendritic processes are being studied. More specifically, the role of various ion channel conductances is explored in terms of integrating dendritic excitatory synaptic input. Biophysical simulations of dendritic behavior show that the complexity of voltage-dependent, non-linear dendritic conductances can produce simplicity in the form of linear synaptic integration. Over increasing levels of synaptic activity, it is shown that two types of voltage-dependent conductances produce linearization over a limited range. This range is determined by the parameters defining the ion channel and the 'passive' properties of the dendrite. A persistent sodium and a transient A-type potassium channel were considered at steady-state transmembrane potentials in the vicinity of and hyperpolarized to the threshold for action potential initiation. The persistent sodium is seen to amplify and linearize the synaptic input over a short range of low synaptic activity. In contrast, the A-type potassium channel has a broader linearization range but tends to operate at higher levels of synaptic bombardment. Given equivalent 'passive' dendritic properties, the persistent sodium is found to be less costly than the A-type potassium in linearizing synaptic input.

  5. The many costs of sex.

    PubMed

    Lehtonen, Jussi; Jennions, Michael D; Kokko, Hanna

    2012-03-01

    Explaining the evolution of sex is challenging for biologists. A 'twofold cost' compared with asexual reproduction is often quoted. If a cost of this magnitude exists, the benefits of sex must be large for it to have evolved and be maintained. Focusing on benefits can be misleading, as this sidelines important questions about the cost of sex: what is the source of the twofold cost: males, genome dilution or both? Does the cost deviate from twofold? What other factors make sex costly? How should the costs of sex be empirically measured? The total cost of sex and how it varies in different contexts must be known to determine the benefits needed to account for the origin and maintenance of sex.

  6. Aerobraking cost/risk decisions

    NASA Technical Reports Server (NTRS)

    Spencer, David A.; Tolson, Robert

    2005-01-01

    this paper provides a brief history of past and future aerobraking missions, describes the aerobraking technique, summarizes the costs associated with aerobraking, and concludes with a suggested methodology for evaluating the cost/risk trade when selecting the aerobraking approach.

  7. Army Manpower Cost System (AMCOS) Economic and Budget Cost Models.

    DTIC Science & Technology

    1985-06-30

    STANDARDS - 963 - A ZRDMServices0opaiy in (o FINAL REPORT Tm ARMY MANPOWER COST SYSTEM4 (ANCOS) ECONOMIC AND BUDGET I COST MODELS CONTRACT NO. N00014...34-- . . .+r7’’ .•. .’. FINAL REPORT ARMY MANPOWER COST SYSTEM (AMCOS) ECONOMIC AND BUDGET COST MODELS CONTRACT NO. N00014-84-C-0712 - JUNE 30, 1985...lack, the Army Research Institute is supporting the development of a family of models in the Army Manpower Cost System -AMCOS). .. ": The work reported

  8. Wind Integration Cost and Cost-Causation: Preprint

    SciTech Connect

    Milligan, M.; Kirby, B.; Holttinen, H.; Kiviluoma, J.; Estanqueiro, A.; Martin-Martinez, S.; Gomez-Lazaro, E.; Peneda, I.; Smith, C.

    2013-10-01

    The question of wind integration cost has received much attention in the past several years. The methodological challenges to calculating integration costs are discussed in this paper. There are other sources of integration cost unrelated to wind energy. A performance-based approach would be technology neutral, and would provide price signals for all technology types. However, it is difficult to correctly formulate such an approach. Determining what is and is not an integration cost is challenging. Another problem is the allocation of system costs to one source. Because of significant nonlinearities, this can prove to be impossible to determine in an accurate and objective way.

  9. Cost analysis for procedure comparisons.

    PubMed

    Trowers, E A; Batra, S C; Buessler, J; Anderson, L K

    1995-01-01

    Using the methodology of activity-based costing as a conceptual framework, the authors present the potential cost reduction of a new office routine and a medical procedure. The costs of a new instrument for colorectal cancer screening and a new surveying and follow-up of at-risk patients show that time and relevant costs in the G.I Clinic and G.I Endoscopy Lab were significantly reduced.

  10. Cost of dementia in Switzerland.

    PubMed

    Kraft, Eliane; Marti, Michael; Werner, Sarah; Sommer, Heini

    2010-09-10

    The aim of this study was (a) to estimate the cost of dementia in Switzerland, (b) to compare the average annual cost for people with dementia who live at home and those living in an institution and (c) to analyse how the average cost per person with dementia who lives at home increases with the severity of dementia. This prevalence-based cost-of-illness study from a societal perspective combined top-down and bottom-up approaches and included both direct and indirect costs of dementia. Cost estimations were based on Swiss national statistics and surveys, as well as international reviews and expert interviews. The total annual cost of dementia amounted up to CHF 6.3 billion for the year 2007. Together, institutional and informal care accounted for over 90% of the cost. The average annual cost was estimated at CHF 55'300 per person with dementia who lives at home and at CHF 68'900 per person who lives in an institution. The cost per person living at home with severe dementia was nearly five times the cost per person with mild dementia. The present study indicates that dementia imposes a considerable economic burden on Swiss society. The cost of dementia is dominated by the costs of care. Diagnosis and treatment related costs are minor. These findings are consistent with contemporary international studies on the subject. The contribution of informal caregivers is substantial since they account for 44% of the total cost of dementia (based on market cost valuation). Given demographic developments in Switzerland, healthcare decision making should have an interest in securing this potential for the future.

  11. Anatomy of backcountry management costs

    Treesearch

    Herbert E Echelberger; Harriet J. Plumley; Harriet J. Plumley

    1986-01-01

    Operation and management costs for several dispersed overnight site locations and backcountry trails in the White Mountain National Forest were studied. Average annual costs ranged from $200 to $1,500 per mile for trails and from $0.35 to $4.29 per visitor for overnight sites. Average annual costs for trails and overnight sites increased with elevation and use levels,...

  12. ARSENIC REMOVAL COST ESTIMATING PROGRAM

    EPA Science Inventory

    The Arsenic Removal Cost Estimating program (Excel) calculates the costs for using adsorptive media and anion exchange treatment systems to remove arsenic from drinking water. The program is an easy-to-use tool to estimate capital and operating costs for three types of arsenic re...

  13. LIFE CYCLE COSTING IN INDUSTRY

    DTIC Science & Technology

    The widespread use of Life Cycle Costing in non-defense industry and the enthusiasm exhibited toward it by company officials give strong support to...the value and the validity of the Life Cycle Cost concept. Industry’s ability to overcome problems associated with Life Cycle Costing provides

  14. Creative Control of Building Costs.

    ERIC Educational Resources Information Center

    Hunt, William Dudley, Jr., Ed.

    Architects and other authorities interested in cost control examine the importance and use of its methods and principles. They outline the major factors in design and construction that determine building costs. The discussions include those elements of maintenance, repair, and replacement that add to the cost of a finished building during its…

  15. ARSENIC REMOVAL COST ESTIMATING PROGRAM

    EPA Science Inventory

    The Arsenic Removal Cost Estimating program (Excel) calculates the costs for using adsorptive media and anion exchange treatment systems to remove arsenic from drinking water. The program is an easy-to-use tool to estimate capital and operating costs for three types of arsenic re...

  16. Reliability and cost analysis methods

    NASA Technical Reports Server (NTRS)

    Suich, Ronald C.

    1991-01-01

    In the design phase of a system, how does a design engineer or manager choose between a subsystem with .990 reliability and a more costly subsystem with .995 reliability? When is the increased cost justified? High reliability is not necessarily an end in itself but may be desirable in order to reduce the expected cost due to subsystem failure. However, this may not be the wisest use of funds since the expected cost due to subsystem failure is not the only cost involved. The subsystem itself may be very costly. We should not consider either the cost of the subsystem or the expected cost due to subsystem failure separately but should minimize the total of the two costs, i.e., the total of the cost of the subsystem plus the expected cost due to subsystem failure. This final report discusses the Combined Analysis of Reliability, Redundancy, and Cost (CARRAC) methods which were developed under Grant Number NAG 3-1100 from the NASA Lewis Research Center. CARRAC methods and a CARRAC computer program employ five models which can be used to cover a wide range of problems. The models contain an option which can include repair of failed modules.

  17. Attrition Cost Model Instruction Manual

    ERIC Educational Resources Information Center

    Yanagiura, Takeshi

    2012-01-01

    This instruction manual explains in detail how to use the Attrition Cost Model program, which estimates the cost of student attrition for a state's higher education system. Programmed with SAS, this model allows users to instantly calculate the cost of attrition and the cumulative attrition rate that is based on the most recent retention and…

  18. Hidden Costs of School Construction.

    ERIC Educational Resources Information Center

    Glass, Thomas E.

    1999-01-01

    Costs that may increase the original school construction estimates include school-design inefficiency, architect fees, and costs for land, site development, technology, demolition, consultants, and security. A quality-review team can plan to avoid hidden costs and ensure that the new facility will meet instructional needs at the least possible…

  19. An introduction to cost analysis.

    PubMed

    Camponovo, Ernest

    2015-04-01

    This article describes the basics of cost accounting for healthcare providers and how these concepts relate to decision making in medical practice. By understanding cost accounting and cost analysis, providers can be better prepared to compete and survive in a changing healthcare environment.

  20. The Costs of Knowledge

    NASA Technical Reports Server (NTRS)

    Prusak, Laurence

    2008-01-01

    Acquiring knowledge-genuinely learning something new-requires the consent and commitment of the person you're trying to learn from. In contrast to information, which can usually be effectively transmitted in a document or diagram, knowledge comes from explaining, clarifying, questioning, and sometimes actually working together. Getting this kind of attention and commitment often involves some form of negotiation, since even the most generous person's time and energy are limited. Few experts sit around waiting to share their knowledge with strangers or casual acquaintances. In reasonably collaborative enterprises- I think NASA is one-this sort of negotiation isn't too onerous. People want to help each other and share what they know, so the "cost" of acquiring knowledge is relatively low. In many organizations (and many communities and countries), however, there are considerable costs associated with this activity, and many situations in which negotiations fail. The greatest knowledge cost is in and adopting knowledge to one's own use. Sometimes this means formally organizing what one learns in writing. Sometimes it means just taking time to reflect on someone else's thoughts and experiences-thinking about knowledge that is not exactly what you need but can lead you to develop ideas that will be useful. A long, discursive conversation, with all the back-and-forth that defines conversation, can be a mechanism of knowledge exchange. I have seen many participants at NASA APPEL Masters Forums talking, reflecting, and thinking-adapting what they are hearing to their own needs. Knowledge transfer is not a simple proposition. An enormous amount of information flows through the world every day, but knowledge is local, contextual, and "stickyn-that is, it takes real effort to move it from one place to another. There is no way around this. To really learn a subject, you have to work at it, you have to pay your "knowledge dues." So while, thanks to advances in technology