Concave microwell plate facilitates chondrogenesis from mesenchymal stem cells.

Science.gov (United States)

Ko, Ji-Yun; Im, Gun-Il

2016-11-01

To compare in vitro chondrogenesis from bone marrow-derived mesenchymal stem cells using concave microwell plates with those obtained using culture tubes. Pellets cultured in concave microwell plates had a significantly higher level of GAG per DNA content and greater proteoglycan content than those cultured in tubes at day 7 and 14. Three chondrogenic markers, SOX-9, COL2A1 and aggrecan, showed significantly higher expression in pellets cultured in concave microwell plates than those cultured in tubes at day 7 and 14. At day 21, there was not a significant difference in the expression of these markers. COL10A1, the typical hypertrophy marker, was significantly lower in concave microwell plates during the whole culture period. Runx-2, a marker of hypertrophy and osteogenesis, was significantly lower at day 7 in pellets cultured in concave microwell plates than those cultured in tubes. Concave microwell plates provide a convenient and effective tool for the study of in vitro chondrogenesis and may replace the use of propylene culture tube.

Novel high-NA MRF toolpath supports production of concave hemispheres

Science.gov (United States)

Maloney, Chris; Supranowitz, Chris; Dumas, Paul

2017-10-01

Many optical system designs rely on high numerical aperture (NA) optics, including lithography and defense systems. Lithography systems require high-NA optics to image the fine patterns from a photomask, and many defense systems require the use of domes. The methods for manufacturing such optics with large half angles have often been treated as proprietary by most manufacturers due to the challenges involved. In the past, many high-NA concave surfaces could not be polished by magnetorheological finishing (MRF) due to collisions with the hardware underneath the polishing head. By leveraging concepts that were developed to enable freeform raster MRF capabilities, QED Technologies has implemented a novel toolpath to facilitate a new high-NA rotational MRF mode. This concept involves the use of the B-axis (rotational axis) in combination with a "virtual-axis" that utilizes the geometry of the polishing head. Hardware collisions that previously restricted the concave half angle limit can now be avoided and the new functionality has been seamlessly integrated into the software. This new MRF mode overcomes past limitations for polishing concave surfaces to now accommodate full concave hemispheres as well as extend the capabilities for full convex hemispheres. We discuss some of the previous limitations, and demonstrate the extended capabilities using this novel toolpath. Polishing results are used to qualify the new toolpath to ensure similar results to the "standard" rotational MRF mode.

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

Science.gov (United States)

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.

Cylindrical concave body of composite fibrous material

International Nuclear Information System (INIS)

1979-01-01

The invention is concerned with a cylindrical concave body of compound fibrous material which is intended to be exposed to high rotation speeds around its own longitudinal axis. The concave body in question has at least one layer of fibrils that are interwoven and enclose an identical angle with the longitudinal axis of the concave body in both directions. The concave body in question also has at least a second layer of fibrils that run in the direction of the circumference and are fitted radially to the outside. The cylindrical concave body of the invention is particularly well suited for application as a rotor tube in a gas ultra-centrifuge

Log-concavity property for some well-known distributions

Directory of Open Access Journals (Sweden)

G. R. Mohtashami Borzadaran

2011-12-01

Full Text Available Interesting properties and propositions, in many branches of science such as economics have been obtained according to the property of cumulative distribution function of a random variable as a concave function. Caplin and Nalebuff (1988,1989, Bagnoli and Khanna (1989 and Bagnoli and Bergstrom (1989 , 1989, 2005 have discussed the log-concavity property of probability distributions and their applications, especially in economics. Log-concavity concerns twice differentiable real-valued function g whose domain is an interval on extended real line. g as a function is said to be log-concave on the interval (a,b if the function ln(g is a concave function on (a,b. Log-concavity of g on (a,b is equivalent to g'/g being monotone decreasing on (a,b or (ln(g" 6] have obtained log-concavity for distributions such as normal, logistic, extreme-value, exponential, Laplace, Weibull, power function, uniform, gamma, beta, Pareto, log-normal, Student's t, Cauchy and F distributions. We have discussed and introduced the continuous versions of the Pearson family, also found the log-concavity for this family in general cases, and then obtained the log-concavity property for each distribution that is a member of Pearson family. For the Burr family these cases have been calculated, even for each distribution that belongs to Burr family. Also, log-concavity results for distributions such as generalized gamma distributions, Feller-Pareto distributions, generalized Inverse Gaussian distributions and generalized Log-normal distributions have been obtained.

ON THE GENERALIZED CONVEXITY AND CONCAVITY

Directory of Open Access Journals (Sweden)

Bhayo B.

2015-11-01

Full Text Available A function ƒ : R+ → R+ is (m1, m2-convex (concave if ƒ(m1(x,y ≤ (≥ m2(ƒ(x, ƒ(y for all x,y Є R+ = (0,∞ and m1 and m2 are two mean functions. Anderson et al. [1] studies the dependence of (m1, m2-convexity (concavity on m1 and m2 and gave the sufficient conditions of (m1, m2-convexity and concavity of a function defined by Maclaurin series. In this paper, we make a contribution to the topic and study the (m1, m2-convexity and concavity of a function where m1 and m2 are identric mean, Alzer mean mean. As well, we prove a conjecture posed by Bruce Ebanks in [2].

Fast approximate convex decomposition using relative concavity

KAUST Repository

Ghosh, Mukulika; Amato, Nancy M.; Lu, Yanyan; Lien, Jyh-Ming

2013-01-01

Approximate convex decomposition (ACD) is a technique that partitions an input object into approximately convex components. Decomposition into approximately convex pieces is both more efficient to compute than exact convex decomposition and can also generate a more manageable number of components. It can be used as a basis of divide-and-conquer algorithms for applications such as collision detection, skeleton extraction and mesh generation. In this paper, we propose a new method called Fast Approximate Convex Decomposition (FACD) that improves the quality of the decomposition and reduces the cost of computing it for both 2D and 3D models. In particular, we propose a new strategy for evaluating potential cuts that aims to reduce the relative concavity, rather than absolute concavity. As shown in our results, this leads to more natural and smaller decompositions that include components for small but important features such as toes or fingers while not decomposing larger components, such as the torso, that may have concavities due to surface texture. Second, instead of decomposing a component into two pieces at each step, as in the original ACD, we propose a new strategy that uses a dynamic programming approach to select a set of n c non-crossing (independent) cuts that can be simultaneously applied to decompose the component into n c+1 components. This reduces the depth of recursion and, together with a more efficient method for computing the concavity measure, leads to significant gains in efficiency. We provide comparative results for 2D and 3D models illustrating the improvements obtained by FACD over ACD and we compare with the segmentation methods in the Princeton Shape Benchmark by Chen et al. (2009) [31]. © 2012 Elsevier Ltd. All rights reserved.

Fast approximate convex decomposition using relative concavity

KAUST Repository

Ghosh, Mukulika

2013-02-01

Approximate convex decomposition (ACD) is a technique that partitions an input object into approximately convex components. Decomposition into approximately convex pieces is both more efficient to compute than exact convex decomposition and can also generate a more manageable number of components. It can be used as a basis of divide-and-conquer algorithms for applications such as collision detection, skeleton extraction and mesh generation. In this paper, we propose a new method called Fast Approximate Convex Decomposition (FACD) that improves the quality of the decomposition and reduces the cost of computing it for both 2D and 3D models. In particular, we propose a new strategy for evaluating potential cuts that aims to reduce the relative concavity, rather than absolute concavity. As shown in our results, this leads to more natural and smaller decompositions that include components for small but important features such as toes or fingers while not decomposing larger components, such as the torso, that may have concavities due to surface texture. Second, instead of decomposing a component into two pieces at each step, as in the original ACD, we propose a new strategy that uses a dynamic programming approach to select a set of n c non-crossing (independent) cuts that can be simultaneously applied to decompose the component into n c+1 components. This reduces the depth of recursion and, together with a more efficient method for computing the concavity measure, leads to significant gains in efficiency. We provide comparative results for 2D and 3D models illustrating the improvements obtained by FACD over ACD and we compare with the segmentation methods in the Princeton Shape Benchmark by Chen et al. (2009) [31]. © 2012 Elsevier Ltd. All rights reserved.

Alpha-Concave Hull, a Generalization of Convex Hull

OpenAIRE

Asaeedi, Saeed; Didehvar, Farzad; Mohades, Ali

2013-01-01

Bounding hull, such as convex hull, concave hull, alpha shapes etc. has vast applications in different areas especially in computational geometry. Alpha shape and concave hull are generalizations of convex hull. Unlike the convex hull, they construct non-convex enclosure on a set of points. In this paper, we introduce another generalization of convex hull, named alpha-concave hull, and compare this concept with convex hull and alpha shape. We show that the alpha-concave hull is also a general...

Convex and Radially Concave Contoured Distributions

Directory of Open Access Journals (Sweden)

Wolf-Dieter Richter

2015-01-01

Full Text Available Integral representations of the locally defined star-generalized surface content measures on star spheres are derived for boundary spheres of balls being convex or radially concave with respect to a fan in Rn. As a result, the general geometric measure representation of star-shaped probability distributions and the general stochastic representation of the corresponding random vectors allow additional specific interpretations in the two mentioned cases. Applications to estimating and testing hypotheses on scaling parameters are presented, and two-dimensional sample clouds are simulated.

Directable weathering of concave rock using curvature estimation.

Science.gov (United States)

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.

Au@Pd core-shell nanobricks with concave structures and their catalysis of ethanol oxidation.

Science.gov (United States)

Wang, Wenjin; Zhang, Jie; Yang, Shengchun; Ding, Bingjun; Song, Xiaoping

2013-10-01

Au@Pd core-shell nanobricks (CNBs) with concave surfaces and Pd shells with a thickness of approximately 5 nm were synthesized by co-reduction of HAuCl4 and H2 PdCl4 in the presence of Au seeds and Ag ions. These as-synthesized concave CNBs exhibit significantly enhanced catalytic activity for the electrooxidation of ethanol in alkaline media compared to the commercially-used Pd black. The improved performance of the Au@Pd CNBs can be attributed to the exposed stepped surfaces, high-index facets, and the synergistic effects of the core and shell metals. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integration of polystyrene microlenses with both convex and concave profiles in a polymer-based microfluidic system

KAUST Repository

Fan, Yiqiang

2013-12-20

This paper reports a new technique of fabricating polystyrene microlenses with both convex and concave profiles that are integrated in polymer-based microfluidic system. The polystyrene microlenses, or microlens array, are fabricated using the free-surface thermal compression molding method. The laser fabricated poly(methyl methacrylate) (PMMA) sheet is used as the mold for the thermal compression molding process. With different surface treatment methods of the PMMA mold, microlenses with either convex or concave profiles could be achieved during the thermal molding process. By integrating the microlenses in the microfluidic systems, observing the flow inside the microchannels is easier. This new technique is rapid, low cost, and it does not require cleanroom facilities. Microlenses with both convex and concave profiles can be easily fabricated and integrated in microfluidic system with this technique. © 2013 Springer-Verlag Berlin Heidelberg.

Neural Network to Solve Concave Games

OpenAIRE

Liu, Zixin; Wang, Nengfa

2014-01-01

The issue on neural network method to solve concave games is concerned. Combined with variational inequality, Ky Fan inequality, and projection equation, concave games are transformed into a neural network model. On the basis of the Lyapunov stable theory, some stability results are also given. Finally, two classic games’ simulation results are given to illustrate the theoretical results.

Log-concave Probability Distributions: Theory and Statistical Testing

DEFF Research Database (Denmark)

An, Mark Yuing

1996-01-01

This paper studies the broad class of log-concave probability distributions that arise in economics of uncertainty and information. For univariate, continuous, and log-concave random variables we prove useful properties without imposing the differentiability of density functions. Discrete...... and multivariate distributions are also discussed. We propose simple non-parametric testing procedures for log-concavity. The test statistics are constructed to test one of the two implicati ons of log-concavity: increasing hazard rates and new-is-better-than-used (NBU) property. The test for increasing hazard...... rates are based on normalized spacing of the sample order statistics. The tests for NBU property fall into the category of Hoeffding's U-statistics...

The concave iris in pigment dispersion syndrome.

Science.gov (United States)

Liu, Lance; Ong, Ee Lin; Crowston, Jonathan

2011-01-01

To visualize the changes of the iris contour in patients with pigment dispersion syndrome after blinking, accommodation, and pharmacologic miosis using anterior segment optical coherence tomography. Observational case series. A total of 33 eyes of 20 patients with pigment dispersion syndrome. Each eye was imaged along the horizontal 0- to 180-degree meridian using the Visante Anterior Segment Imaging System (Carl Zeiss Meditec, Dublin, CA). Scans were performed at baseline and after focusing on an internal fixation target for 5 minutes, forced blinking, accommodation, and pharmacologic miosis with pilocarpine 2%. Quantitative analysis of the changes in the iris configuration. After 5 minutes of continual fixation, the iris became planar with the mean ± standard deviation curvature decreasing from 214 ± 74 μm to 67 ± 76 μm (P pigment dispersion syndrome after forced blinking, but the iris concavity recovered to 227 ± 113 μm (P = 0.34) and 238 ± 119 μm (P = 0.19) with the -3.0 and -6.0 diopter lenses, respectively. Pilocarpine-induced miosis caused the iris to assume a planar configuration in all subjects. This study shows that the iris in pigment dispersion syndrome assumes a planar configuration when fixating and that the concavity of the iris surface is not restored by blinking. Accommodation restored the iris concavity, suggesting that the posterior curvature of the iris in pigment dispersion syndrome is induced and probably maintained, at least in part, by accommodation. Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Apparatus including concave reflectors and a line of optical fibers

International Nuclear Information System (INIS)

Dolan, J.T.

1992-01-01

This patent describes an apparatus including a radiation source which emits in a multiplicity of directions for focusing radiation on an object which may receive radiation within a certain solid angle. It comprises a first reflector and a second reflector, the first reflector being elliptical in cross section and having a first focus and a second focus, the second reflector being circular in cross section and having a center, and a radius equal to the distance between the second reflector and the first focus, the first reflector and the second reflector being arranged so that a concave reflecting surface of the first reflector faces a concave reflecting surface of the second reflector, and so arranged that the first focus of the first reflector corresponds to the center of the second reflector, the radiation source being an elongated discharge bulb, the object being a group of two or more optical fibers defining at least one line of optical fibers which are located at the second focus of the first reflector

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

Science.gov (United States)

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

Partial null astigmatism-compensated interferometry for a concave freeform Zernike mirror

Science.gov (United States)

Dou, Yimeng; Yuan, Qun; Gao, Zhishan; Yin, Huimin; Chen, Lu; Yao, Yanxia; Cheng, Jinlong

2018-06-01

Partial null interferometry without using any null optics is proposed to measure a concave freeform Zernike mirror. Oblique incidence on the freeform mirror is used to compensate for astigmatism as the main component in its figure, and to constrain the divergence of the test beam as well. The phase demodulated from the partial nulled interferograms is divided into low-frequency phase and high-frequency phase by Zernike polynomial fitting. The low-frequency surface figure error of the freeform mirror represented by the coefficients of Zernike polynomials is reconstructed from the low-frequency phase, applying the reverse optimization reconstruction technology in the accurate model of the interferometric system. The high-frequency surface figure error of the freeform mirror is retrieved from the high-frequency phase adopting back propagating technology, according to the updated model in which the low-frequency surface figure error has been superimposed on the sag of the freeform mirror. Simulations verified that this method is capable of testing a wide variety of astigmatism-dominated freeform mirrors due to the high dynamic range. The experimental result using our proposed method for a concave freeform Zernike mirror is consistent with the null test result employing the computer-generated hologram.

Pd@Au core-shell nanocrystals with concave cubic shapes: kinetically controlled synthesis and electrocatalytic properties.

Science.gov (United States)

Zhang, Ling; Niu, Wenxin; Zhao, Jianming; Zhu, Shuyun; Yuan, Yali; Hua, Lianzhe; Xu, Guobao

2013-01-01

A new type of concave cubic Pd@Au core-shell nanocrystals is synthesized through a kinetically controlled growth process. Pd nanocubes of 56 nm are used as the inner core, and CTAC and Br(-) are used as the capping agent and selective adsorbent, respectively. A suitable ratio of HAuCl4 and cubic Pd seeds and the presence of Br(-) anions are critical to the growth of the concave cubic Pd@Au core-shell nanocrystals. The fast deposition rate on the corners of the cubic Pd seeds promotes the overgrowth of the Au outer shell along the direction, leading to the formation of concave cubic nanostructures. The reduction process is monitored by the surface plasmon resonance spectra of the nanocrystals, and the extinction band became broader and red shifted as the nanocrystals became larger. The electrocatalytic properties of the concave cubic Pd@Au core-shell nanocrystals were investigated with the cathodic electrochemiluminescence reaction of luminol and H2O2. A possible electrocatalytic mechanism was proposed and analyzed.

Availability of cosmetic treatment using novel cosmetics-based material on patients with craniofacial concavity.

Science.gov (United States)

Koyama, Shigeto; Kanetaka, Hiroyasu; Sagehashi, Yoshinori; Sasaki, Keiichi; Sato, Naoko

2018-03-08

Patients treated with maxillofacial prosthetics often experience emotional problems because of the remaining facial skin concavity such as a surgical scar. In such cases, cosmetic treatment can potentially correct their skin tone imperfections and deformities. This study aimed to evaluate the clinical availability of novel cosmetics-based material for craniofacial small concavity by initiating a cosmetic treatment in a preliminary case. Eighteen patients with aesthetic problems such as craniofacial deformities, small defects, and concavities on their faces underwent cosmetic treatment that was performed by makeup practitioners. Data were collected from the patient's charts and a survey questionnaire. A visual analog scale was used to conduct a survey regarding the satisfaction levels of the patients following cosmetic treatment with a novel cosmetics-based material. The cosmetic treatment was performed for a concavity on the left midface of a 67-year-old woman with partial maxillectomy. The novel cosmetics-based material was manufactured from a semi-translucent oil base. The satisfaction level of the patient increased after undergoing the cosmetic treatment. Regarding clinical applications, the novel cosmetics-based material can help reduce their cosmetic disturbance and restore the small deformity. These results suggest that the cosmetic treatment with the novel cosmetics-based material can be used as a subsidiary method for facial prostheses or an independent new method for correcting patients' small craniofacial concavity and for reducing visible deformity. Copyright © 2018 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Evaluation of Parameters Affecting Magnetic Abrasive Finishing on Concave Freeform Surface of Al Alloy via RSM Method

Directory of Open Access Journals (Sweden)

Mehrdad Vahdati

2016-01-01

Full Text Available The attempts of researchers in industries to obtain accurate and high quality surfaces led to the invention of new methods of finishing. Magnetic abrasive finishing (MAF is a relatively new type of finishing in which the magnetic field is used to control the abrasive tools. Applications such as the surface of molds are ones of the parts which require very high surface smoothness. Usually this type of parts has freeform surface. In this study, the effect of magnetic abrasive process parameters on freeform surfaces of parts made of aluminum is examined. This method is obtained through combination of magnetic abrasive process and Control Numerical Computer (CNC. The use of simple hemisphere for installation on the flat area of the magnets as well as magnets’ spark in curve form is a measure done during testing the experiments. The design of experiments is based on response surface methodology. The gap, the rotational speed of the spindle, and the feed rate are found influential and regression equations governing the process are also determined. The impact of intensity of the magnetic field is obtained using the finite element software of Maxwell. Results show that in concave areas of the surface, generally speaking, the surface roughness decreases to 0.2 μm from its initial 1.3 μm roughness. However, in some points the lowest surface roughness of 0.08 μm was measured.

Water experiment of high-speed, free-surface, plane jet along concave wall

International Nuclear Information System (INIS)

Nakamura, Hideo; Ida, Mizuho; Kato, Yoshio; Maekawa, Hiroshi; Itoh, Kazuhiro; Kukita, Yutaka

1997-01-01

In the International Fusion Materials Irradiation Facility (IFMIF), an intense 14 MeV neutron beam will be generated in the high-speed liquid lithium (Li) plane jet target flowing along concave wall in vacuum. As part of the conceptual design activity (CDA) of the IFMIF, the stability of the plane liquid jet flow was studied experimentally with water in a well-defined channel geometry for non-heating condition. A two-dimensional double-reducer nozzle being newly proposed for the IFMIF target successfully provided a high-speed (≤ 17 m/s) stable water jet with uniform velocity distribution at the nozzle exit without flow separation in the nozzle. The free surface of the jet was covered by two-dimensional and/or three-dimensional waves, the size of which did not change much over the tested jet length of ∼130 mm. The jet velocity profile changed around the nozzle exit from uniform to that of free-vortex flow where the product of the radius of stream line and local velocity is constant in the jet thickness. The jet thickness increased immediately after exiting the nozzle because of the velocity profile change. The predicted jet thickness by a modified one-dimensional momentum model agreed with the data well. (author)

Generalized concavity in fuzzy optimization and decision analysis

CERN Document Server

Ramík, Jaroslav

2002-01-01

Convexity of sets in linear spaces, and concavity and convexity of functions, lie at the root of beautiful theoretical results that are at the same time extremely useful in the analysis and solution of optimization problems, including problems of either single objective or multiple objectives. Not all of these results rely necessarily on convexity and concavity; some of the results can guarantee that each local optimum is also a global optimum, giving these methods broader application to a wider class of problems. Hence, the focus of the first part of the book is concerned with several types of generalized convex sets and generalized concave functions. In addition to their applicability to nonconvex optimization, these convex sets and generalized concave functions are used in the book's second part, where decision-making and optimization problems under uncertainty are investigated. Uncertainty in the problem data often cannot be avoided when dealing with practical problems. Errors occur in real-world data for...

Experimental analysis of an MIM capacitor with a concave shield

International Nuclear Information System (INIS)

Liu Lintao; Yu Mingyan; Wang Jinxiang

2009-01-01

A novel shielding scheme is developed by inserting a concave shield between a metal-insulator-metal (MIM) capacitor and the silicon substrate. Chip measurements reveal that the concave shield improves the quality factor by 11% at 11.8 GHz and 14% at 18.8 GHz compared with an unshielded MIM capacitor. It also alleviates the effect on shunt capacitance between the bottom plate of the MIM capacitor and the shield layer. Moreover, because the concave shields simplify substrate modeling, a simple circuit model of the MIM capacitor with concave shield is presented for radio frequency applications.

Bimacrocyclic concave N-heterocyclic carbenes (NHCs): synthesis, structure, and application in catalyses

OpenAIRE

Lüning , Ulrich; Winkelmann , Ole

2009-01-01

Abstract Imidazolinium moieties have been incorporated into bimacrocycles to generate precursors for concave N-heterocyclic carbenes (NHCs). Starting from 2-nitroresorcinol and alkenols, symmetric concave imidazolinium salts 1 were obtained. Bimacrocyclization was achieved via ring closing metathesis (RCM). In an analogous fashion, axially chiral concave imidazolinium salts 2 were obtained by using a naphthalene bridgehead devoid of local C2-symmetry. The concave NHCs derived from ...

Pt3Co concave nanocubes: synthesis, formation understanding, and enhanced catalytic activity toward hydrogenation of styrene.

Science.gov (United States)

Wang, Chenyu; Lin, Cuikun; Zhang, Lihua; Quan, Zewei; Sun, Kai; Zhao, Bo; Wang, Feng; Porter, Nathan; Wang, Yuxuan; Fang, Jiye

2014-02-03

We report a facile synthesis route to prepare high-quality Pt3Co nanocubes with a concave structure, and further demonstrate that these concave Pt3Co nanocubes are terminated with high-index crystal facets. The success of this preparation is highly dependent on an appropriate nucleation process with a successively anisotropic overgrowth and a preservation of the resultant high-index planes by control binding of oleyl-amine/oleic acid with a fine-tuned composition. Using a hydrogenation of styrene as a model reaction, these Pt3Co concave nanocubes as a new class of nanocatalysts with more open structure and active atomic sites located on their high-index crystallographic planes exhibit an enhanced catalytic activity in comparison with low-indexed surface terminated Pt3Co nanocubes in similar size. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhanced Absorption in Organic Thin-Films from Imprinted Concave Nanostructures

DEFF Research Database (Denmark)

Goszczak, Arkadiusz Jaroslaw; Rubahn, Horst-Günter; Madsen, Morten

2017-01-01

In this work, a rapid, replicable method for imprinting concave nanostructures to be used as functional light-trapping nanostructures in organic thin-films is presented. Porous anodic alumina templates were fabricated both by anodization of thick Al foils and by anodization of submicrometer thin Al...... patterns and used for imprinting of spin coated photoresist on glass substrates. We have investigated semi-periodic and aperiodic imprinted large concave patterns fabricated from rigid masters after anodization of Al in H3PO4. We show that metal covered imprinted concaves show enhancement in absorption...

Convexity and concavity constants in Lorentz and Marcinkiewicz spaces

Science.gov (United States)

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].

Modeling of Focused Acoustic Field of a Concave Multi-annular Phased Array Using Spheroidal Beam Equation

Science.gov (United States)

Yu, Li-Li; Shou, Wen-De; Hui, Chun

2012-02-01

A theoretical model of focused acoustic field for a multi-annular phased array on concave spherical surface is proposed. In this model, the source boundary conditions of the spheroidal beam equation (SBE) for multi-annular phased elements are studied. Acoustic field calculated by the dynamic focusing model of SBE is compared with numerical results of the O'Neil and Khokhlov—Zabolotskaya—Kuznetsov (KZK) model, respectively. Axial dynamic focusing and the harmonic effects are presented. The results demonstrate that the dynamic focusing model of SBE is good valid for a concave multi-annular phased array with a large aperture angle in the linear or nonlinear field.

Modeling of Focused Acoustic Field of a Concave Multi-annular Phased Array Using Spheroidal Beam Equation

International Nuclear Information System (INIS)

Yu Lili; Shou Wende; Hui Chun

2012-01-01

A theoretical model of focused acoustic field for a multi-annular phased array on concave spherical surface is proposed. In this model, the source boundary conditions of the spheroidal beam equation (SBE) for multi-annular phased elements are studied. Acoustic field calculated by the dynamic focusing model of SBE is compared with numerical results of the O'Neil and Khokhlov-Zabolotskaya-Kuznetsov (KZK) model, respectively. Axial dynamic focusing and the harmonic effects are presented. The results demonstrate that the dynamic focusing model of SBE is good valid for a concave multi-annular phased array with a large aperture angle in the linear or nonlinear field. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Enhanced Absorption in Organic Thin-Films from Imprinted Concave Nanostructures

Directory of Open Access Journals (Sweden)

Arkadiusz Jarosław GOSZCZAK

2017-02-01

Full Text Available In this work, a rapid, replicable method for imprinting concave nanostructures to be used as functional light-trapping nanostructures in organic thin-films is presented. Porous anodic alumina templates were fabricated both by anodization of thick Al foils and by anodization of submicrometer thin Al films evaporated via e-beam evaporation on Si substrates. The template formation leads to natural patterning of the underlying Al layers that are used as rigid masters for stamp fabrication, after selective etching of the porous anodic alumina. PDMS stamps were made after replicating the Al concave patterns and used for imprinting of spin coated photoresist on glass substrates. We have investigated semi-periodic and aperiodic imprinted large concave patterns fabricated from rigid masters after anodization of Al in H3PO4. We show that metal covered imprinted concaves show enhancement in absorption that is attributed to field enhancement and diffuse scattering, leading to efficient light trapping for a selected active layer material (P3HT:PCBM.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.14188

Concave distal end of ulna metaphysis alone is not a sign of rickets

Energy Technology Data Exchange (ETDEWEB)

Oestreich, Alan E. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, 5031, Cincinnati, OH (United States)

2015-07-15

Statements have been made in the literature and in legal testimony that misrepresent the radiographic finding of concave distal end of the ulnar metaphysis. To demonstrate that a concave distal end of the ossified ulna in infancy can be normal. Eighty distal wrists of randomly selected infants in the first year of life with radiographic evidence that ruled out rickets were reviewed. In 16 of the cases (20%), mild or moderate concavity of the distal end of the ulna was seen. An intact metaphyseal collar of distal radius or ulna confirmed the absence of radiographic rickets. The finding of 20% of concave distal ulnas in the first year of life confirms the widely acknowledged statements that concave distal end of the ulna alone is not indicative of rickets. Statements to the contrary are not justified. (orig.)

Concave distal end of ulna metaphysis alone is not a sign of rickets

International Nuclear Information System (INIS)

Oestreich, Alan E.

2015-01-01

Statements have been made in the literature and in legal testimony that misrepresent the radiographic finding of concave distal end of the ulnar metaphysis. To demonstrate that a concave distal end of the ossified ulna in infancy can be normal. Eighty distal wrists of randomly selected infants in the first year of life with radiographic evidence that ruled out rickets were reviewed. In 16 of the cases (20%), mild or moderate concavity of the distal end of the ulna was seen. An intact metaphyseal collar of distal radius or ulna confirmed the absence of radiographic rickets. The finding of 20% of concave distal ulnas in the first year of life confirms the widely acknowledged statements that concave distal end of the ulna alone is not indicative of rickets. Statements to the contrary are not justified. (orig.)

Field arrangement and dosimetry verification for concave target

International Nuclear Information System (INIS)

Chen Liang; Wang Huankun; Li Yumin

2005-01-01

Objective: To provide a method of radiotherapy field arrangement for concave paraspinal target. Methods: Plan was designed for concave target in wax phantom and the selected patients by the guidance of beam eye view (BEV) provided by a 3D treatment planning system (CREAT EXPERT). In BEV, the inner border of all tangential fields was 2 mm out of the organ at risk (OAR) and the outer border was 5 mm beyond the target. Dosimetry films and ion chamber were used to verify the dose distribution and point dose in the wax phantom. Results: Dose distribution in phantom and patient was homogeneous. The mean dose of OAR in phantom did not exceed 16% of the prescribed dose. Isodose curves dropped more than 8% per mm between the target and OAR in the phantom. Film dosimetry coincided well with the calculated results. Position error in high dose region was with- in 4 mm and absolute dose errors were no more than 5%. Conclusion: Tangential field arrangement is valuable and practical in radiotherapy for concave paraspinal targets. (authors)

Sound concentration caused by curved surfaces

NARCIS (Netherlands)

Vercammen, M.L.S.

2012-01-01

In room acoustics the focusing effect of reflections from concave surfaces is a wellknown problem. Although curved surfaces are found throughout the history of architecture, the occurrence of concave surfaces has tended to increase in modern architecture, due to new techniques in design, materials

STRONG ORACLE OPTIMALITY OF FOLDED CONCAVE PENALIZED ESTIMATION.

Science.gov (United States)

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.

Configuration design and accuracy analysis of a novel magneto rheological finishing machine tool for concave surfaces with small radius of curvature

International Nuclear Information System (INIS)

Liu, Henan; Chen, Mingjun; Yu, Bo; Zhen, Fang

2016-01-01

Magnetorheological finishing (MRF) is a computer-controlled deterministic polishing technique that is widely used in the production of high-quality optics. In order to overcome the defects of existing MRF processes that are unable to achieve concave surfaces with small radius of curvature, a configuration method of a novel structured MRF machine tool using small ball-end permanent-magnet polishing head is proposed in this paper. The preliminary design focuses on the structural configuration of the machine, which includes the machine body, motion units and accessory equipment, and so on. Structural deformation and fabrication accuracy of the machine are analyzed theoretically, in which the reasonable structure sizes, manufacturing errors and assembly errors of main structural components are given for configuration optimization. Based on the theoretical analysis, a four-axes linkage MRF machine tool is developed. Preliminary experiments of spot polishing are carried out and the results indicate that the proposed MRF process can achieve stable polishing area which meets requirement of deterministic polishing. A typical small-bore complex component is polished on the developed device and fine surface quality is obtained with sphericity of the finished spherical surfaces 1.3 μm and surface roughness Ra less than 0.018 μm.

Controlled synthesis of concave tetrahedral palladium nanocrystals by reducing Pd(acac)2 with carbon monoxide

International Nuclear Information System (INIS)

Zhu, Hai; Chi, Quan; Zhao, Yanxi; Li, Chunya; Tang, Heqing; Li, Jinlin; Huang, Tao; Liu, Hanfan

2012-01-01

Graphical abstract: By using CO as a reducing agent, uniform and well-defined concave tetrahedral Pd nanocrystals were successfully synthesized. CO flow rate was the most essential for the formation of the concave tetrahedral nanostructures. The morphologies and sizes of the final products can be well controlled by adjusting the flow rate of CO. Highlights: ► By using CO as a reducing agent, concave tetrahedral Pd nanocrystals were obtained. ► CO flow rate is critical to the formation of concave tetrahedral Pd nanocrystals. ► The selective adsorption of CO on (1 1 0) facets is essential to concave Pd tetrahedra. -- Abstract: CO reducing strategy to control the morphologies of palladium nanocrystals was investigated. By using CO as a reducing agent, uniform and well-defined concave tetrahedral Pd nanocrystals with a mean size of about 55 ± 2 nm were readily synthesized with Pd(acac) 2 as a precursor and PVP as a stabilizer. The structures of the as-prepared Pd nanocrystals were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), ultraviolet–visible (UV–vis) absorption spectroscopy and electrochemical measurements. The results demonstrated that CO was the most essential for the formation of the concave tetrahedral Pd nanostructures. The morphologies and sizes of the final products can be well controlled by adjusting the flow rate of CO. The most appropriate CO flow rate, temperature and time for the formation of the ideal concave tetrahedral Pd nanocrystals was 0.033 mL s −1 , 100 °C and 3 h, respectively.

Smith-Purcell radiation from concave dotted gratings

Science.gov (United States)

Sergeeva, D. Yu.; Tishchenko, A. A.; Aryshev, A. S.; Strikhanov, M. N.

2018-02-01

We present the first-principles theory of Smith-Purcell effect from the concave dotted grating consisting of bent chains of separated micro- or nanoparticles. The numerical analysis demonstrates that the obtained spectral-angular distributions change significantly depending on the structure of the grating.

Optimal Portfolio Selection Under Concave Price Impact

International Nuclear Information System (INIS)

Ma Jin; Song Qingshuo; Xu Jing; Zhang Jianfeng

2013-01-01

In this paper we study an optimal portfolio selection problem under instantaneous price impact. Based on some empirical analysis in the literature, we model such impact as a concave function of the trading size when the trading size is small. The price impact can be thought of as either a liquidity cost or a transaction cost, but the concavity nature of the cost leads to some fundamental difference from those in the existing literature. We show that the problem can be reduced to an impulse control problem, but without fixed cost, and that the value function is a viscosity solution to a special type of Quasi-Variational Inequality (QVI). We also prove directly (without using the solution to the QVI) that the optimal strategy exists and more importantly, despite the absence of a fixed cost, it is still in a “piecewise constant” form, reflecting a more practical perspective.

Optimal Portfolio Selection Under Concave Price Impact

Energy Technology Data Exchange (ETDEWEB)

Ma Jin, E-mail: jinma@usc.edu [University of Southern California, Department of Mathematics (United States); Song Qingshuo, E-mail: songe.qingshuo@cityu.edu.hk [City University of Hong Kong, Department of Mathematics (Hong Kong); Xu Jing, E-mail: xujing8023@yahoo.com.cn [Chongqing University, School of Economics and Business Administration (China); Zhang Jianfeng, E-mail: jianfenz@usc.edu [University of Southern California, Department of Mathematics (United States)

2013-06-15

In this paper we study an optimal portfolio selection problem under instantaneous price impact. Based on some empirical analysis in the literature, we model such impact as a concave function of the trading size when the trading size is small. The price impact can be thought of as either a liquidity cost or a transaction cost, but the concavity nature of the cost leads to some fundamental difference from those in the existing literature. We show that the problem can be reduced to an impulse control problem, but without fixed cost, and that the value function is a viscosity solution to a special type of Quasi-Variational Inequality (QVI). We also prove directly (without using the solution to the QVI) that the optimal strategy exists and more importantly, despite the absence of a fixed cost, it is still in a 'piecewise constant' form, reflecting a more practical perspective.

Principle and geomorphological applicability of summit level and base level technique using Aster Gdem satellite-derived data and the original software Baz

Directory of Open Access Journals (Sweden)

Akihisa Motoki

2015-05-01

Full Text Available This article presents principle and geomorphological applicability of summit level technique using Aster Gdem satellite-derived topographicdata. Summit level corresponds to thevirtualtopographic surface constituted bylocalhighest points, such as peaks and plateau tops, and reconstitutes palaeo-geomorphology before the drainage erosion. Summit level map is efficient for reconstitution of palaeo-surfaces and detection of active tectonic movement. Base level is thevirtualsurface composed oflocallowest points, as valley bottoms. The difference between summit level and base level is called relief amount. Thesevirtualmapsareconstructed by theoriginalsoftwareBaz. Themacroconcavity index, MCI, is calculated from summit level and relief amount maps. The volume-normalised three-dimensional concavity index, TCI, is calculated from hypsometric diagram. The massifs with high erosive resistance tend to have convex general form and low MCI and TCI. Those with low resistance have concave form and high MCI and TCI. The diagram of TCI vs. MCI permits to distinguish erosive characteristics of massifs according to their constituent rocks. The base level map for ocean bottom detects the basement tectonic uplift which occurred before the formation of the volcanic seamounts.

A versatile curve-fit model for linear to deeply concave rank abundance curves

NARCIS (Netherlands)

Neuteboom, J.H.; Struik, P.C.

2005-01-01

A new, flexible curve-fit model for linear to concave rank abundance curves was conceptualized and validated using observational data. The model links the geometric-series model and log-series model and can also fit deeply concave rank abundance curves. The model is based ¿ in an unconventional way

Concave pulse shaping of a circularly polarized laser pulse from non-uniform overdense plasmas

Energy Technology Data Exchange (ETDEWEB)

Hur, Min Sup [School of Natural Science, UNIST, BanYeon-Ri 100, Ulju-gun, Ulsan, 689-798 (Korea, Republic of); Kulagin, Victor V. [Sternberg Astronomical Institute, Moscow State University, Universitetsky prosp. 13, Moscow, 119992 (Russian Federation); Suk, Hyyong, E-mail: hysuk@gist.ac.kr [Department of Physics and Photon Science, GIST, 123 Cheomdan-gwangiro, Buk-gu, Gwangju, 500-712 (Korea, Republic of)

2015-03-20

Pulse shaping of circularly polarized laser pulses in nonuniform overdense plasmas are investigated numerically. Specifically we show by two-dimensional particle-in-cell simulations the generation of a concave pulse front of a circularly polarized, a few tens of petawatt laser pulse from a density-tapered, overdense plasma slab. The concept used for the transverse-directional shaping is the differential transmittance depending on the plasma density, and the laser intensity. For suitable selection of the slab parameters for the concave pulse shaping, we studied numerically the pulse transmittance, which can be used for further parameter design of the pulse shaping. The concavely shaped circularly polarized pulse is expected to add more freedom in controlling the ion-beam characteristics in the RPDA regime. - Highlights: • Laser pulse shaping for a concave front by non-uniform overdense plasma was studied. • Particle-in-cell (PIC) simulations were used for the investigation. • A laser pulse can be shaped by a density-tapered overdense plasma. • The concave and sharp pulse front are useful in many laser–plasma applications. • They are important for ion acceleration, especially in the radiation pressure dominant regime.

Site-Selective Carving and Co-Deposition: Transformation of Ag Nanocubes into Concave Nanocrystals Encased by Au-Ag Alloy Frames.

Science.gov (United States)

Ahn, Jaewan; Wang, Daniel; Ding, Yong; Zhang, Jiawei; Qin, Dong

2018-01-23

We report a facile synthesis of Ag nanocubes with concave side faces and Au-Ag alloy frames, namely Ag@Au-Ag concave nanocrystals, by titrating HAuCl 4 solution into an aqueous mixture of Ag nanocubes, ascorbic acid (H 2 Asc), NaOH, and cetyltrimethylammonium chloride (CTAC) at an initial pH of 11.6 under ambient conditions. Different from all previous studies involving poly(vinylpyrrolidine), the use of CTAC at a sufficiently high concentration plays an essential role in carving away Ag atoms from the side faces through galvanic replacement. Concurrent co-deposition of Au and Ag atoms via chemical reduction at orthogonal sites on the surface of Ag nanocubes leads to the generation of Ag@Au-Ag concave nanocrystals with well-defined and controllable structures. Specifically, in the presence of CTAC-derived Cl - ions, the titrated HAuCl 4 is maintained in the AuCl 4 - species, enabling its galvanic replacement with the Ag atoms located on the side faces of nanocubes. The released Ag + ions can be retained in the soluble form of AgCl 2 - by complexing with the Cl - ions. Both the AuCl 4 - and AgCl 2 - in the solution are then reduced by ascorbate monoanion, a product of the neutralization reaction between H 2 Asc and NaOH, to Au and Ag atoms for their preferential co-deposition onto the edges and corners of the Ag nanocubes. Compared with Ag nanocubes, the Ag@Au-Ag concave nanocrystals exhibit much stronger SERS activity at an excitation of 785 nm, making it feasible to monitor the Au-catalyzed reduction of 4-nitrothiophenol by NaBH 4 in situ. When the Ag cores are removed, the concave nanocrystals evolve into Au-Ag nanoframes with controllable ridge thicknesses.

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

Science.gov (United States)

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.

Visualizing RNA Secondary Structure Base Pair Binding Probabilities using Nested Concave Hulls

OpenAIRE

Sansen , Joris; Bourqui , Romain; Thebault , Patricia; Allali , Julien; Auber , David

2015-01-01

International audience; The challenge 1 of the BIOVIS 2015 design contest consists in designing an intuitive visual depiction of base pairs binding probabilities for secondary structure of ncRNA. Our representation depicts the potential nucleotide pairs binding using nested concave hulls over the computed MFE ncRNA secondary structure. Thus, it allows to identify regions with a high level of uncertainty in the MFE computation and the structures which seem to match to reality.

Fabricating small-scale, curved, polymeric structures with convex and concave menisci through interfacial free energy equilibrium.

Science.gov (United States)

Cheng, Chao-Min; Matsuura, Koji; Wang, I-Jan; Kuroda, Yuka; LeDuc, Philip R; Naruse, Keiji

2009-11-21

Polymeric curved structures are widely used in imaging systems including optical fibers and microfluidic channels. Here, we demonstrate that small-scale, poly(dimethylsiloxane) (PDMS)-based, curved structures can be fabricated through controlling interfacial free energy equilibrium. Resultant structures have a smooth, symmetric, curved surface, and may be convex or concave in form based on surface tension balance. Their curvatures are controlled by surface characteristics (i.e., hydrophobicity and hydrophilicity) of the molds and semi-liquid PDMS. In addition, these structures are shown to be biocompatible for cell culture. Our system provides a simple, efficient and economical method for generating integrateable optical components without costly fabrication facilities.

Reactive solid surface morphology variation via ionic diffusion.

Science.gov (United States)

Sun, Zhenchao; Zhou, Qiang; Fan, Liang-Shih

2012-08-14

In gas-solid reactions, one of the most important factors that determine the overall reaction rate is the solid morphology, which can be characterized by a combination of smooth, convex and concave structures. Generally, the solid surface structure varies in the course of reactions, which is classically noted as being attributed to one or more of the following three mechanisms: mechanical interaction, molar volume change, and sintering. Here we show that if a gas-solid reaction involves the outward ionic diffusion of a solid-phase reactant then this outward ionic diffusion could eventually smooth the surface with an initial concave and/or convex structure. Specifically, the concave surface is filled via a larger outward diffusing surface pointing to the concave valley, whereas the height of the convex surface decreases via a lower outward diffusion flux in the vertical direction. A quantitative 2-D continuum diffusion model is established to analyze these two morphological variation processes, which shows consistent results with the experiments. This surface morphology variation by solid-phase ionic diffusion serves to provide a fourth mechanism that supplements the traditionally acknowledged solid morphology variation or, in general, porosity variation mechanisms in gas-solid reactions.

Log-Concavity Properties of Minkowski Valuations

OpenAIRE

Berg, Astrid; Parapatits, Lukas; Schuster, Franz E.; Weberndorfer, Manuel

2014-01-01

New Orlicz Brunn-Minkowski inequalities are established for rigid motion compatible Minkowski valuations of arbitrary degree. These extend classical log-concavity properties of intrinsic volumes and generalize seminal results of Lutwak and others. Two different approaches which refine previously employed techniques are explored. It is shown that both lead to the same class of Minkowski valuations for which these inequalities hold. An appendix by Semyon Alesker contains the proof of a new clas...

Whole surface image reconstruction for machine vision inspection of fruit

Science.gov (United States)

Reese, D. Y.; Lefcourt, A. M.; Kim, M. S.; Lo, Y. M.

2007-09-01

Automated imaging systems offer the potential to inspect the quality and safety of fruits and vegetables consumed by the public. Current automated inspection systems allow fruit such as apples to be sorted for quality issues including color and size by looking at a portion of the surface of each fruit. However, to inspect for defects and contamination, the whole surface of each fruit must be imaged. The goal of this project was to develop an effective and economical method for whole surface imaging of apples using mirrors and a single camera. Challenges include mapping the concave stem and calyx regions. To allow the entire surface of an apple to be imaged, apples were suspended or rolled above the mirrors using two parallel music wires. A camera above the apples captured 90 images per sec (640 by 480 pixels). Single or multiple flat or concave mirrors were mounted around the apple in various configurations to maximize surface imaging. Data suggest that the use of two flat mirrors provides inadequate coverage of a fruit but using two parabolic concave mirrors allows the entire surface to be mapped. Parabolic concave mirrors magnify images, which results in greater pixel resolution and reduced distortion. This result suggests that a single camera with two parabolic concave mirrors can be a cost-effective method for whole surface imaging.

Classroom Note: Concavity and the Second Law of Thermodynamics

Science.gov (United States)

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.

Manipulating the kinetics of seeded growth for edge-selective metal deposition and the formation of concave au nanocrystals.

Science.gov (United States)

Laskar, Moitree; Zhong, Xiaolan; Li, Zhi-Yuan; Skrabalak, Sara E

2013-10-01

By manipulating the kinetics of seeded growth through judicious control of reaction conditions, edge-selective metal deposition can be achieved to synthesize new Au nanostructures with face-centered concavities, referred to herein as Au overgrown trisoctahedra. These nanostructures display higher sensitivity to changes in refractive index compared to both Au traditional trisoctahedra and the Au nanocube seeds from which they are grown. Often, concave nanostructures are achieved by selective etching processes or corner-selective overgrowth and adopt a stellated profile rather than a profile with face-centered concavities. The presented results illustrate another strategy toward concave nanostructures and can facilitate the synthesis of new concave nanostructures for applications in catalysis and chemical sensing. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Local matching indicators for concave transport costs

OpenAIRE

Delon , Julie; Salomon , Julien; Sobolevskii , A.

2010-01-01

International audience; In this note, we introduce a class of indicators that enable to compute efficiently optimal transport plans associated to arbitrary distributions of $N$ demands and $N$ supplies in $\\mathbf{R}$ in the case where the cost function is concave. The computational cost of these indicators is small and independent of $N$. A hierarchical use of them enables to obtain an efficient algorithm.

Structural Health Monitoring of Tall Buildings with Numerical Integrator and Convex-Concave Hull Classification

Directory of Open Access Journals (Sweden)

Suresh Thenozhi

2012-01-01

Full Text Available An important objective of health monitoring systems for tall buildings is to diagnose the state of the building and to evaluate its possible damage. In this paper, we use our prototype to evaluate our data-mining approach for the fault monitoring. The offset cancellation and high-pass filtering techniques are combined effectively to solve common problems in numerical integration of acceleration signals in real-time applications. The integration accuracy is improved compared with other numerical integrators. Then we introduce a novel method for support vector machine (SVM classification, called convex-concave hull. We use the Jarvis march method to decide the concave (nonconvex hull for the inseparable points. Finally the vertices of the convex-concave hull are applied for SVM training.

A theoretical model for flow boiling CHF from short concave heaters

International Nuclear Information System (INIS)

Galloway, J.E.; Mudawar, I.

1995-01-01

Experiments were performed to enable the development of a new theoretical mode for the enhancement in CHF commonly observed with flow boiling on concave heater as compared to straight heaters. High-speed video imaging and photomicrography were employed to capture the trigger mechanism for CHF each type heater. A wavy vapor layer was observed to engulf the heater surface in each case, permitting liquid access to the surface only in regions where depressions (troughs) in the liquid vapor interface made contact with the surface. CHF in each case occurred when the pressure force exerted upon the wavy vapor-liquid inter ace in the contact region could no longer overcome the momentum of the vapor produced in these regional. Shorter interfacial wavelengths with greater curvature were measured on the curve, heater than on the straight heater, promoting a greater pressure force on the wave interface and a corresponding increase in CHF for the curved heater. A theoretics. CHF model is developed from these observations, based upon a new theory for hydrodynamic instability, along a curved interface. CHF data are predicted with good accuracy for both heaters. 23 refs., 9 figs

The Backscattering Phase Function for a Sphere with a Two-Scale Relief of Rough Surface

Science.gov (United States)

Klass, E. V.

2017-12-01

The backscattering of light from spherical surfaces characterized by one and two-scale roughness reliefs has been investigated. The analysis is performed using the three-dimensional Monte-Carlo program POKS-RG (geometrical-optics approximation), which makes it possible to take into account the roughness of objects under study by introducing local geometries of different levels. The geometric module of the program is aimed at describing objects by equations of second-order surfaces. One-scale roughness is set as an ensemble of geometric figures (convex or concave halves of ellipsoids or cones). The two-scale roughness is modeled by convex halves of ellipsoids, with surface containing ellipsoidal pores. It is shown that a spherical surface with one-scale convex inhomogeneities has a flatter backscattering phase function than a surface with concave inhomogeneities (pores). For a sphere with two-scale roughness, the dependence of the backscattering intensity is found to be determined mostly by the lower-level inhomogeneities. The influence of roughness on the dependence of the backscattering from different spatial regions of spherical surface is analyzed.

A new signal restoration method based on deconvolution of the Point Spread Function (PSF) for the Flat-Field Holographic Concave Grating UV spectrometer system

Science.gov (United States)

Dai, Honglin; Luo, Yongdao

2013-12-01

In recent years, with the development of the Flat-Field Holographic Concave Grating, they are adopted by all kinds of UV spectrometers. By means of single optical surface, the Flat-Field Holographic Concave Grating can implement dispersion and imaging that make the UV spectrometer system design quite compact. However, the calibration of the Flat-Field Holographic Concave Grating is very difficult. Various factors make its imaging quality difficult to be guaranteed. So we have to process the spectrum signal with signal restoration before using it. Guiding by the theory of signals and systems, and after a series of experiments, we found that our UV spectrometer system is a Linear Space- Variant System. It means that we have to measure PSF of every pixel of the system which contains thousands of pixels. Obviously, that's a large amount of calculation .For dealing with this problem, we proposes a novel signal restoration method. This method divides the system into several Linear Space-Invariant subsystems and then makes signal restoration with PSFs. Our experiments turn out that this method is effective and inexpensive.

Sharing a common resource with concave benefits

OpenAIRE

Ambec, S.

2006-01-01

A group of agents enjoy concave and single-peak benefit functions from consuming a shared resource. They also value money (transfers). The resource is scarce in the sense that not everybody can consume its peak. The paper characterizes the unique (resource and money) allocation that is efficient, incentive compatible and equal-sharing individual rational. It can be implemented (i) by selling the resource or taxing extraction and redistributing the money collected equally, or (ii) by assigning...

Processing convexity and concavity along a 2-D contour: figure-ground, structural shape, and attention.

Science.gov (United States)

Bertamini, Marco; Wagemans, Johan

2013-04-01

Interest in convexity has a long history in vision science. For smooth contours in an image, it is possible to code regions of positive (convex) and negative (concave) curvature, and this provides useful information about solid shape. We review a large body of evidence on the role of this information in perception of shape and in attention. This includes evidence from behavioral, neurophysiological, imaging, and developmental studies. A review is necessary to analyze the evidence on how convexity affects (1) separation between figure and ground, (2) part structure, and (3) attention allocation. Despite some broad agreement on the importance of convexity in these areas, there is a lack of consensus on the interpretation of specific claims--for example, on the contribution of convexity to metric depth and on the automatic directing of attention to convexities or to concavities. The focus is on convexity and concavity along a 2-D contour, not convexity and concavity in 3-D, but the important link between the two is discussed. We conclude that there is good evidence for the role of convexity information in figure-ground organization and in parsing, but other, more specific claims are not (yet) well supported.

Hydrogen storage in pure and Li-doped carbon nanopores: combined effects of concavity and doping.

Science.gov (United States)

Cabria, I; López, M J; Alonso, J A

2008-04-14

Density functional calculations are reported for the adsorption of molecular hydrogen on carbon nanopores. Two models for the pores have been considered: (i) The inner walls of (7,7) carbon nanotubes and (ii) the highly curved inner surface of nanotubes capped on one end. The effect of Li doping is investigated in all cases. The hydrogen physisorption energies increase due to the concavity effect inside the clean nanotubes and on the bottom of the capped nanotubes. Li doping also enhances the physisorption energies. The sum of those two effects leads to an increase by a factor of almost 3 with respect to the physisorption in the outer wall of undoped nanotubes and in flat graphene. Application of a quantum-thermodynamical model to clean cylindrical pores of diameter 9.5 A, the diameter of the (7,7) tube, indicates that cylindrical pores of this size can store enough hydrogen to reach the volumetric and gravimetric goals of the Department of Energy at 77 K and low pressures, although not at 300 K. The results are useful to explain the experiments on porous carbons. Optimizations of the pore size, concavity, and doping appear as promising alternatives for achieving the goals at room temperature.

Irradiation of target volumes with concave outlines

Energy Technology Data Exchange (ETDEWEB)

De Neve, W; Fortan, L; Derycke, S; Van Duyse, B; DE Wagter, C [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde

1995-12-01

A heuristic planning procedure allowing to obtain a 3-dimensional conformal dose distribution for target volumes with concavities has been investigated. The procedure divides the planning problem into a number of sub-problems each solvable by known methods. By patching together the solutions to the sub-problems, a solution with a predictable dosimetric outcome can be obtained. The procedure can be applied to most 3-dimensional systems. The procedure is described and its applications to the irradiation of neoplasms are discussed. (A.S.).

Irradiation of target volumes with concave outlines

International Nuclear Information System (INIS)

De Neve, W.; Fortan, L.; Derycke, S.; Van Duyse, B.; DE Wagter, C.

1995-01-01

A heuristic planning procedure allowing to obtain a 3-dimensional conformal dose distribution for target volumes with concavities has been investigated. The procedure divides the planning problem into a number of sub-problems each solvable by known methods. By patching together the solutions to the sub-problems, a solution with a predictable dosimetric outcome can be obtained. The procedure can be applied to most 3-dimensional systems. The procedure is described and its applications to the irradiation of neoplasms are discussed. (A.S.)

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

DEFF Research Database (Denmark)

Goszczak, Arkadiusz Jaroslaw; Adam, Jost; Cielecki, Pawel Piotr

2016-01-01

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...

Sensitive visual test for concave diffraction gratings.

Science.gov (United States)

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.

Endophthalmitis after descemet stripping endothelial keratoplasty with concave-oriented dislocation on slit-lamp optical coherence topography.

Science.gov (United States)

Kaiura, Terry L; Ritterband, David C; Koplin, Richard S; Shih, Carolyn; Palmierto, Pat M; Seedor, John A

2010-02-01

To present the first reported case of Descemet membrane stripping endothelial keratoplasty (DSEK)-associated endophthalmitis with concave dislocation on slit-lamp optical coherence topography (SL-OCT). An 86-year-old man underwent DSEK for corneal decompensation secondary to prior surgery. On all postoperative visits, a slit-lamp examination and SL-OCT were performed. On the first postoperative day, the lenticle was dislocated in a concave configuration as imaged with the SL-OCT. On the second postoperative day, the patient had eye pain, nausea, and increased intraocular pressure. On SL-OCT imaging, the concave configuration and fibrin stranding were imaged. With intraocular pressure lowering, the patient's pain subsided, and he was scheduled for a lenticle refloat the following day. The next day, endophthalmitis was diagnosed secondary to exuberant purulent inflammation. At surgery, the lenticle was removed, cultures were obtained, and pars plana vitrectomy and intravitreal injections were administered. Intraoperative cultures were positive for heavy growth of Streptococcus pneumoniae. Endophthalmitis is a potential complication for any intraocular procedure including DSEK. SL-OCT imaging postoperatively may reveal concave lenticle configuration and subtle anterior chamber fibrin stranding may be early sign of endophthalmitis.

Transient river response, captured by channel steepness and its concavity

Science.gov (United States)

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.

An analytic solution for calculating the beam intensity profiles useful to irradiate target volumes with bi-concave outlines

Energy Technology Data Exchange (ETDEWEB)

De Neve, W; Derycke, S; De Wagter, C [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde

1995-12-01

A heuristic planing procedure allowing to obtain a 3-dimensional conformal dose distribution in radiotherapy for target volumes with a bi-concave or multi-concave shape has been developed. The described method is tested on a phantom simulating a pelvic target, described by Brahme.

Concave utility, transaction costs, and risk in measuring discounting of delayed rewards.

Science.gov (United States)

Kirby, Kris N; Santiesteban, Mariana

2003-01-01

Research has consistently found that the decline in the present values of delayed rewards as delay increases is better fit by hyperbolic than by exponential delay-discounting functions. However, concave utility, transaction costs, and risk each could produce hyperbolic-looking data, even when the underlying discounting function is exponential. In Experiments 1 (N = 45) and 2 (N = 103), participants placed bids indicating their present values of real future monetary rewards in computer-based 2nd-price auctions. Both experiments suggest that utility is not sufficiently concave to account for the superior fit of hyperbolic functions. Experiment 2 provided no evidence that the effects of transaction costs and risk are large enough to account for the superior fit of hyperbolic functions.

Thermal-hydraulic performance of a multiple jet cooling module with a concave dimple array in a helium-cooled divertor

Energy Technology Data Exchange (ETDEWEB)

Jung, Hyo-Yeon; Kim, Kwang-Yong, E-mail: kykim@inha.ac.kr

2017-01-15

A numerical study was performed to evaluate the thermal-hydraulic performance of a finger type cooling module, where multiple jets impinge on the surface with concave dimples, in the divertor of a nuclear fusion reactor. Conjugate heat transfer was analyzed in both the solid and fluid domains using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. The computational domain consisted of a single fluid domain and three solid domains: tile, thimble, and cartridge. The numerical results for the temperature variation on the tile were validated in comparison with the experimental data. A parametric study was performed with two design variables, the ratios of dimple diameter and dimple height to the nozzle diameter, and two dimple arrays (inline and staggered arrays). The parametric study showed that the heat transfer rate was increased by up to 2.62% by introducing concave dimples, and that the heat transfer and pressure drop performances increased with increasing diameter and height of the dimples for a specified dimple array.

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

International Nuclear Information System (INIS)

Norek, Małgorzata; Łuka, Grzegorz; Włodarski, Maksymilian

2016-01-01

Highlights: • Al nano-concave arrays with different interpore distance (D c ) were prepared. • PL of ZnO thin films deposited directly on the Al nano-concaves were studied. • The effect of 10 nm Al 2 O 3 spacer on PL emission from ZnO thin films was analyzed. • Plasmonic enhancement of the PL emission was dependent on the D c and the spacer. • The highest 9-fold enhancement was obtained for the Al/ZnO sample with D c ∼333 nm. - Abstract: Surface plasmons (SPs) supported by Al nano-concave arrays with increasing interpore distance (D c ) 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 − Al 2 O 3 spacer was placed between the textured Al and the ZnO films (the Al/Al 2 O 3 -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 (D c = 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/Al 2 O 3 -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/Al 2 O 3 -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.

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

Energy Technology Data Exchange (ETDEWEB)

Norek, Małgorzata, E-mail: mnorek@wat.edu.pl [Department of Advanced Materials and Technologies, Faculty of Advanced Technologies and Chemistry, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Łuka, Grzegorz [Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw (Poland); Włodarski, Maksymilian [Institute of Optoelectronics, Military University of Technology, Str. Kaliskiego 2, 00-908 Warszawa (Poland)

2016-10-30

Highlights: • Al nano-concave arrays with different interpore distance (D{sub c}) were prepared. • PL of ZnO thin films deposited directly on the Al nano-concaves were studied. • The effect of 10 nm Al{sub 2}O{sub 3} spacer on PL emission from ZnO thin films was analyzed. • Plasmonic enhancement of the PL emission was dependent on the D{sub c} and the spacer. • The highest 9-fold enhancement was obtained for the Al/ZnO sample with D{sub c} ∼333 nm. - Abstract: Surface plasmons (SPs) supported by Al nano-concave arrays with increasing interpore distance (D{sub c}) 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 − Al{sub 2}O{sub 3} spacer was placed between the textured Al and the ZnO films (the Al/Al{sub 2}O{sub 3}-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 (D{sub c} = 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{sub (0,1)} SPP resonance mode. In the Al/Al{sub 2}O{sub 3}-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{sub (0,1)} plasmonic mode. The results obtained in this work indicate that better tuning of the NBE − λ{sub (0,1)} SPP resonance mode coupling is possible through a proper modification of geometrical parameters in the Al/Al{sub 2}O{sub 3}-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

1-concave basis for TU games and the library game

NARCIS (Netherlands)

Driessen, Theo; Khmelnitskaya, Anna Borisovna; Sales, J.

2012-01-01

The study of 1-convex/1-concave TU games possessing a nonempty core and for which the nucleolus is linear was initiated by Driessen and Tijs (Methods Oper. Res. 46:395–406, 1983) and Driessen (OR Spectrum 7:19–26, 1985). However, until recently appealing abstract and practical examples of these

The Successor Function and Pareto Optimal Solutions of Cooperative Differential Systems with Concavity. I

DEFF Research Database (Denmark)

Andersen, Kurt Munk; Sandqvist, Allan

1997-01-01

We investigate the domain of definition and the domain of values for the successor function of a cooperative differential system x'=f(t,x), where the coordinate functions are concave in x for any fixed value of t. Moreover, we give a characterization of a weakly Pareto optimal solution.......We investigate the domain of definition and the domain of values for the successor function of a cooperative differential system x'=f(t,x), where the coordinate functions are concave in x for any fixed value of t. Moreover, we give a characterization of a weakly Pareto optimal solution....

Designs of contraction nozzle and concave back-wall for IFMIF target

Energy Technology Data Exchange (ETDEWEB)

Ida, Mizuho E-mail: ida@ifmif.tokai.jaeri.go.jp; Nakamura, Hideo; Nakamura, Hiroo; Takeuchi, Hiroshi

2004-02-01

For the liquid lithium flow target of International Fusion Materials Irradiation Facility (IFMIF), the double reducer (two-step contraction) nozzle with a high-contraction ratio of 10 which generated high-speed uniform jet flows up to 20 m/s was proposed. Multi-dimensional hydraulic analyses were carried out to verify the performance of the proposed nozzle. The analytical results showed that the double reducer nozzle would well generate high-speed uniform flow, while one-step contraction nozzle generated non-uniform flow and resulted in flow thickening at the beam footprint. For the target design, the range of the concave back-wall radius with no lithium boiling due to the centrifugal force and proper component arrangement in the irradiation test cell was determined by the thermal-hydraulic analysis of a free-surface flow. It was verified that the back-wall radius from 0.25 to 10 m was acceptable in the velocity range of 10-20 m/s.

Designs of contraction nozzle and concave back-wall for IFMIF target

International Nuclear Information System (INIS)

Ida, Mizuho; Nakamura, Hideo; Nakamura, Hiroo; Takeuchi, Hiroshi

2004-01-01

For the liquid lithium flow target of International Fusion Materials Irradiation Facility (IFMIF), the double reducer (two-step contraction) nozzle with a high-contraction ratio of 10 which generated high-speed uniform jet flows up to 20 m/s was proposed. Multi-dimensional hydraulic analyses were carried out to verify the performance of the proposed nozzle. The analytical results showed that the double reducer nozzle would well generate high-speed uniform flow, while one-step contraction nozzle generated non-uniform flow and resulted in flow thickening at the beam footprint. For the target design, the range of the concave back-wall radius with no lithium boiling due to the centrifugal force and proper component arrangement in the irradiation test cell was determined by the thermal-hydraulic analysis of a free-surface flow. It was verified that the back-wall radius from 0.25 to 10 m was acceptable in the velocity range of 10-20 m/s

Monotonicity and Logarithmic Concavity of Two Functions Involving Exponential Function

Science.gov (United States)

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"…

Fabrication of complex free-standing nanostructures with concave and convex curvature via the layer-by-layer approach.

Science.gov (United States)

Raoufi, Mohammad; Schönherr, Holger

2014-02-18

We report on the fabrication of unprecedented free-standing complex polymeric nanoobjects, which possess both concave and convex curvatures, by exploiting the layer-by-layer (LBL) deposition of polyelectrolytes. In a combined top-down/bottom-up replication approach pore diameter-modulated anodic aluminum oxide (AAO) templates, fabricated by temperature modulation hard anodization (TMHA), were replicated with multilayers of poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) to yield open nanotubes with diameters in the wide and narrow segments of 210 and 150 nm, respectively. To obtain stable pore diameter-modulated nanopores, which possess segment lengths between 1 and 5 μm and 5 and 10 μm in the narrow and wide pore portion, respectively, conventional hard anodization of aluminum was followed by a subsequent temperature-modulated anodization. After removing the backside aluminum electrode, silanizing the aluminum oxide, and passivating the exposed membrane surface with a thin layer of gold, PSS and PAH were deposited alternatingly to yield LBL multilayers. For optimized LBL multilayer thicknesses and compactness, established in separate experiments on silicon substrates and nanoporous AAO with straight pores, free-standing polymeric nanoobjects with concave and convex curvatures, were obtained. These were stable for wall thickness to pore diameter ratios of ≥0.08.

A facile method to fabricate close-packed concave microlens array on cylindrical glass

International Nuclear Information System (INIS)

Deng, Zefang; Chen, Feng; Yang, Qing; Liu, Hewei; Bian, Hao; Du, Guangqing; Hu, Yang; Si, Jinhai; Meng, Xiangwei; Hou, Xun

2012-01-01

This work presents a facile method to fabricate concave microlens arrays (MLAs) with controllable shape and high fill factor on cylindrical silica glass by a femtosecond laser-enhanced chemical wet etching process. The hexagonal and rectangular MLAs are flexibly fabricated on the silica glass cylinder with a diameter of 3 mm. The morphological characteristics of MLAs are measured by a scanning electron microscope and a laser scanning confocal microscope. The measurements show that the good uniformity and high packing density MLA structures are generated. It has also been demonstrated that the shape and size of the concave structures could be easily tuned by changing laser power and the arrangement of laser exposure spots. The convex MLAs replicated by the polymer casting method experience excellent image quality. (paper)

Ribosomal protein L5 has a highly twisted concave surface and flexible arms responsible for rRNA binding.

Science.gov (United States)

Nakashima, T; Yao, M; Kawamura, S; Iwasaki, K; Kimura, M; Tanaka, I

2001-05-01

Ribosomal protein L5 is a 5S rRNA binding protein in the large subunit and plays an essential role in the promotion of a particular conformation of 5S rRNA. The crystal structure of the ribosomal protein L5 from Bacillus stearothermophilus has been determined at 1.8 A resolution. The molecule consists of a five-stranded antiparallel beta-sheet and four alpha-helices, which fold in a way that is topologically similar to the ribonucleoprotein (RNP) domain. The molecular shape and electrostatic representation suggest that the concave surface and loop regions are involved in 5S rRNA binding. To identify amino acid residues responsible for 5S rRNA binding, we made use of Ala-scanning mutagenesis of evolutionarily conserved amino acids occurring in the beta-strands and loop regions. The mutations of Asn37 at the beta1-strand and Gln63 at the loop between helix 2 and beta3-strand as well as that of Phe77 at the tip of the loop structure between the beta2- and beta3-strands caused a significant reduction in 5S rRNA binding. In addition, the mutations of Thr90 on the beta3-strand and Ile141 and Asp144 at the loop between beta4- and beta5-strands moderately reduced the 5S rRNA-binding affinity. Comparison of these results with the more recently analyzed structure of the 50S subunit from Haloarcula marismortui suggests that there are significant differences in the structure at N- and C-terminal regions and probably in the 5S rRNA binding.

A Lower Bound on the Differential Entropy of Log-Concave Random Vectors with Applications

Directory of Open Access Journals (Sweden)

Arnaud Marsiglietti

2018-03-01

Full Text Available We derive a lower bound on the differential entropy of a log-concave random variable X in terms of the p-th absolute moment of X. The new bound leads to a reverse entropy power inequality with an explicit constant, and to new bounds on the rate-distortion function and the channel capacity. Specifically, we study the rate-distortion function for log-concave sources and distortion measure d ( x , x ^ = | x − x ^ | r , with r ≥ 1 , and we establish that the difference between the rate-distortion function and the Shannon lower bound is at most log ( π e ≈ 1 . 5 bits, independently of r and the target distortion d. For mean-square error distortion, the difference is at most log ( π e 2 ≈ 1 bit, regardless of d. We also provide bounds on the capacity of memoryless additive noise channels when the noise is log-concave. We show that the difference between the capacity of such channels and the capacity of the Gaussian channel with the same noise power is at most log ( π e 2 ≈ 1 bit. Our results generalize to the case of a random vector X with possibly dependent coordinates. Our proof technique leverages tools from convex geometry.

[Influence of different surface treatments on porcelain surface topography].

Science.gov (United States)

Tai, Yinxia; Zhu, Xianchun; Sen, Yan; Liu, Chang; Zhang, Xian; Shi, Xueming

2013-02-01

To evaluate the influence of different surface treatments on porcelain surface topography. Metal ceramic prostheses in 6 groups were treated according to the different surface treatment methods, and the surface topography was observed through scanning electron microscope (SEM). Group A was the control one (untreated), group B was etched by 9.6% hydrofluoric acid(HF), group C was deglazed by grinding and then etched by 9.6% HF, group D was treated with Nd: YAG laser irradiation(0.75 W) and HF etching, group E was treated with Nd: YAG laser irradiation (1.05 W) and HF etching, and group F was treated with laser irradiation (1.45 W) and HF etching. Surface topography was different in different groups. A lot of inerratic cracks with the shapes of rhombuses and grid, and crater with a shape of circle were observed on the ceramic surface after treatment with energy parameters of 1.05 W Nd: YAG laser irradiation and 9.6% HF etching (group E). Surface topography showed a lot of concaves on the inner wall of the cracks, and the concaves with diameter of 1-5 microm could be observed on the inner wall of the holes, which had a diameter of 20 microm under SEM. The use of Nd: YAG laser irradiation with the energy parameters of 1.05 W and the HF with a concentration of 9.6% can evenly coarsen the porcelain surface, that is an effective surface treatment method.

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

Science.gov (United States)

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

Environmental protection stability of river bed and banks using convex, concave, and linear bed sills.

Science.gov (United States)

Keshavarzi, Alireza; Noori, Lila Khaje

2010-12-01

River bed scourings are a major environmental problem for fish and aquatic habitat resources. In this study, to prevent river bed and banks from scouring, different types of bed sills including convex, concave and linear patterns were installed in a movable channel bed in a laboratory flume. The bed sills were tested with nine different arrangements and under different flow conditions. To find the most effective bed sill pattern, the scouring depth was measured downstream of the bed sill for a long experimental duration. The scour depth was measured at the middle and at the end of each experimental test for different ratios of the arch radius to the channel width [r/w]. The experimental results indicated that the convex pattern with r/w=0.35 produced minimum bed scouring depth at the center line whereas the concave pattern with r/w=0.23 produced the minimum scour depth at the wall banks. Therefore, the convex pattern was the most effective configuration for prevention of scouring at the center line of the river while the concave pattern was very effective to prevent scouring at the river banks. These findings can be suggested to be used in practical applications.

Singular elliptic systems involving concave terms and critical Caffarelli-Kohn-Nirenberg exponents

Directory of Open Access Journals (Sweden)

Mohammed E. O. El Mokhtar

2012-03-01

Full Text Available In this article, we establish the existence of at least four solutions to a singular system with a concave term, a critical Caffarelli-Kohn-Nirenberg exponent, and sign-changing weight functions. Our main tools are the Nehari manifold and the mountain pass theorem.

Pierce-type electron gun with a large concave LaB6 cathode

International Nuclear Information System (INIS)

Shintake, Tumoru; Ohba, Kunio; Matoba, Masaru; Katase, Akira

1981-01-01

A Pierce-type electron gun with a concave cathode of lanthanum hexaboride (LaB 6 ) 30 mm in diameter is described. At an accelerating voltage of 3 kV and a cathode temperature of 1340 0 C, a focussed electron beam of DC 300 mA was obtained. (author)

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

Science.gov (United States)

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…

Transient disturbance growth in flows over convex surfaces

Science.gov (United States)

Karp, Michael; Hack, M. J. Philipp

2017-11-01

Flows over curved surfaces occur in a wide range of applications including airfoils, compressor and turbine vanes as well as aerial, naval and ground vehicles. In most of these applications the surface has convex curvature, while concave surfaces are less common. Since monotonic boundary-layer flows over convex surfaces are exponentially stable, they have received considerably less attention than flows over concave walls which are destabilized by centrifugal forces. Non-modal mechanisms may nonetheless enable significant disturbance growth which can make the flow susceptible to secondary instabilities. A parametric investigation of the transient growth and secondary instability of flows over convex surfaces is performed. The specific conditions yielding the maximal transient growth and strongest instability are identified. The effect of wall-normal and spanwise inflection points on the instability process is discussed. Finally, the role and significance of additional parameters, such as the geometry and pressure gradient, is analyzed.

A numerical study on the behavior of the water meniscus formed between a flat surface and a flat or circular tip

Energy Technology Data Exchange (ETDEWEB)

Son, Sung Wan; Ha, Man Yeong; Yoon, Hyun Sik; Kim, Chang Min [Pusan National University, Busan (Korea, Republic of); Kim, Sang Sun [Korea Aerospace Industries, Sacheon (Korea, Republic of)

2014-04-15

We numerically investigated the behavior of the water meniscus formed between a flat surface and a tip surface, which is flat or circular in shape, using the lattice Boltzmann method (LBM). The shape of the water meniscus formed between the flat bottom surface and the tip surface depends on the tip shape and the interaction between the water meniscus and the bottom or tip surface. The interaction is determined by the contact angles of the bottom and tip surfaces, resulting in different contact lengths between the water meniscus and the bottom or tip surface. The difference in these contact lengths depends on the effects of both the tip curvature and the interaction between the water meniscus and the bottom or tip surface. We classified the shapes of the water meniscus into seven different patterns as a function of the contact angles of the flat bottom and tip surfaces: concave, semi-concave, inverse semi-concave, column, convex, semiconvex, and inverse semi-convex.

A numerical study on the behavior of the water meniscus formed between a flat surface and a flat or circular tip

International Nuclear Information System (INIS)

Son, Sung Wan; Ha, Man Yeong; Yoon, Hyun Sik; Kim, Chang Min; Kim, Sang Sun

2014-01-01

We numerically investigated the behavior of the water meniscus formed between a flat surface and a tip surface, which is flat or circular in shape, using the lattice Boltzmann method (LBM). The shape of the water meniscus formed between the flat bottom surface and the tip surface depends on the tip shape and the interaction between the water meniscus and the bottom or tip surface. The interaction is determined by the contact angles of the bottom and tip surfaces, resulting in different contact lengths between the water meniscus and the bottom or tip surface. The difference in these contact lengths depends on the effects of both the tip curvature and the interaction between the water meniscus and the bottom or tip surface. We classified the shapes of the water meniscus into seven different patterns as a function of the contact angles of the flat bottom and tip surfaces: concave, semi-concave, inverse semi-concave, column, convex, semiconvex, and inverse semi-convex

Wear Behavior of Medium Carbon Steel with Biomimetic Surface Under Starved Lubricated Conditions

Science.gov (United States)

Zhang, Zhihui; Shao, Feixian; Liang, Yunhong; Lin, Pengyu; Tong, Xin; Ren, Luquan

2017-07-01

Friction and wear under starved lubrication condition are both key life-related factors for mechanical performance of many structural parts. In this paper, different surface morphologies on medium carbon steel were fabricated using laser, inspired by the surface coupling effect of biological system. The friction and sliding wear behaviors of biomimetic specimens (characterized by convex and concave units on the specimen surface) were studied under starved lubrication condition. The stress distribution on different sliding surfaces under sliding friction was studied using finite element method. The results showed that the tribological performance of studied surfaces under starved lubrication condition depended not only on the surface morphology but also on the structure of biomimetic units below surface (subsurface structure). The friction coefficient of biomimetic surface was effectively reduced by the concave unit depth, while the refined microstructure with higher hardness led to the much better wear resistance. In addition to lubricant reserving and wear debris trapping effect derived from the surface concave morphology, it was believed that the well-formed subsurface structure of biomimetic units could carry much heavy loads against tribopair, which enhanced the function of surface topography and resulted in complementary lubrication in the wear contact area. The uniform stress distribution on the entire biomimetic surface also played an important role in stabilizing the friction coefficient and reducing the wear cracks.

Assessment of CHF enhancement mechanisms in a curved, rectangular channel subjected to concave heating

International Nuclear Information System (INIS)

Sturgis, J.C.; Mudawar, I.

1999-01-01

An experimental study was undertaken to examine the enhancement in critical heat flux (CHF) provided by streamwise curvature. Curved and straight rectangular flow channels were fabricated with identical 5.0 x 2.5 mm cross sections and heated lengths of 101.6 mm in which the heat was applied to only one wall--the concave wall (32.3 mm radius) in the curved channel and a side wall in the straight. Tests were conducted using FC-72 liquid with mean inlet velocity and outlet subcooling of 0.25 to 10 m s -1 and 3 to 29 C, respectively. Centripetal acceleration for curved flow reached 315 times earth's gravitational acceleration. Critical heat flux was enhanced due to flow curvature at all conditions but the enhancement decreased with increasing subcooling. For near-saturated conditions, the enhancement was approximately 60% while for highly subcooled flow it was only 20%. The causes for the enhancement were identified as (1) increased pressure on the liquid-vapor interface at wetting fronts, (2) buoyancy forces and (3) increased subcooling at the concave wall. Flow visualization tests were conducted in transparent channels to explore the role of buoyancy forces in enhancing the critical heat flux. These forces were observed to remove vapor from the concave wall and distribute it throughout the cross section. Vapor removal was only effective at near-saturated conditions, yielding the observed substantial enhancement in CHF relative to the straight channel

Diffusion accessibility as a method for visualizing macromolecular surface geometry.

Science.gov (United States)

Tsai, Yingssu; Holton, Thomas; Yeates, Todd O

2015-10-01

Important three-dimensional spatial features such as depth and surface concavity can be difficult to convey clearly in the context of two-dimensional images. In the area of macromolecular visualization, the computer graphics technique of ray-tracing can be helpful, but further techniques for emphasizing surface concavity can give clearer perceptions of depth. The notion of diffusion accessibility is well-suited for emphasizing such features of macromolecular surfaces, but a method for calculating diffusion accessibility has not been made widely available. Here we make available a web-based platform that performs the necessary calculation by solving the Laplace equation for steady state diffusion, and produces scripts for visualization that emphasize surface depth by coloring according to diffusion accessibility. The URL is http://services.mbi.ucla.edu/DiffAcc/. © 2015 The Protein Society.

Effects of atomic-level nano-structured hydroxyapatite on adsorption of bone morphogenetic protein-7 and its derived peptide by computer simulation.

Science.gov (United States)

Wang, Qun; Wang, Menghao; Lu, Xiong; Wang, Kefeng; Fang, Liming; Ren, Fuzeng; Lu, Guoming

2017-11-09

Hydroxyapatite (HA) is the principal inorganic component of bones and teeth and has been widely used as a bone repair material because of its good biocompatibility and bioactivity. Understanding the interactions between proteins and HA is crucial for designing biomaterials for bone regeneration. In this study, we evaluated the effects of atomic-level nano-structured HA (110) surfaces on the adsorption of bone morphogenetic protein-7 (BMP-7) and its derived peptide (KQLNALSVLYFDD) using molecular dynamics and density functional theory methods. The results indicated that the atomic-level morphology of HA significantly affected the interaction strength between proteins and HA substrates. The interactions of BMP-7 and its derived peptide with nano-concave and nano-pillar HA surfaces were stronger than those with flat or nano-groove HA surfaces. The results also revealed that if the groove size of nano-structured HA surfaces matched that of residues in the protein or peptide, these residues were likely to spread into the grooves of the nano-groove, nano-concave, and nano-pillar HA, further strengthening the interactions. These results are helpful in better understanding the adsorption behaviors of proteins onto nano-structured HA surfaces, and provide theoretical guidance for designing novel bioceramic materials for bone regeneration and tissue engineering.

Outlet strut fracture and leaflet escape of Bjork-Shiley convexo-concave valve.

Science.gov (United States)

Uchino, Gaku; Yoshida, Hideo; Sakoda, Naoya; Hattori, Shigeru; Kawabata, Takuya; Saiki, Munehiro; Fujita, Yasufumi; Yunoki, Keiji; Hisamochi, Kunikazu; Mine, Yoshinari

2017-06-01

Prosthetic valve fracture is a serious complication and may arise in patient post-valve replacement. We experienced an outlet strut fracture and leaflet escape of a Bjork-Shiley convexo-concave valve. We performed an emergency redo mitral valve replacement and successfully retrieved the fractured strut and escaped leaflet from superficial femoral artery and the abdominal aorta. The patient showed an uneventful postoperative recovery.

Polarization of concave domains by traveling wave pinning.

Directory of Open Access Journals (Sweden)

Slawomir Bialecki

Full Text Available Pattern formation is one of the most fundamental yet puzzling phenomena in physics and biology. We propose that traveling front pinning into concave portions of the boundary of 3-dimensional domains can serve as a generic gradient-maintaining mechanism. Such a mechanism of domain polarization arises even for scalar bistable reaction-diffusion equations, and, depending on geometry, a number of stationary fronts may be formed leading to complex spatial patterns. The main advantage of the pinning mechanism, with respect to the Turing bifurcation, is that it allows for maintaining gradients in the specific regions of the domain. By linking the instant domain shape with the spatial pattern, the mechanism can be responsible for cellular polarization and differentiation.

Study on Dynamic Development of Three-dimensional Weld Pool Surface in Stationary GTAW

Science.gov (United States)

Huang, Jiankang; He, Jing; He, Xiaoying; Shi, Yu; Fan, Ding

2018-04-01

The weld pool contains abundant information about the welding process. In particular, the type of the weld pool surface shape, i. e., convex or concave, is determined by the weld penetration. To detect it, an innovative laser-vision-based sensing method is employed to observe the weld pool surface of the gas tungsten arc welding (GTAW). A low-power laser dots pattern is projected onto the entire weld pool surface. Its reflection is intercepted by a screen and captured by a camera. Then the dynamic development process of the weld pool surface can be detected. By observing and analyzing, the change of the reflected laser dots reflection pattern, for shape of the weld pool surface shape, was found to closely correlate to the penetration of weld pool in the welding process. A mathematical model was proposed to correlate the incident ray, reflected ray, screen and surface of weld pool based on structured laser specular reflection. The dynamic variation of the weld pool surface and its corresponding dots laser pattern were simulated and analyzed. By combining the experimental data and the mathematical analysis, the results show that the pattern of the reflected laser dots pattern is closely correlated to the development of weld pool, such as the weld penetration. The concavity of the pool surface was found to increase rapidly after the surface shape was changed from convex to concave during the stationary GTAW process.

On the equivalence of the Choquet, pan- and concave integrals on finite spaces

Czech Academy of Sciences Publication Activity Database

Ouyang, Y.; Li, J.; Mesiar, Radko

2017-01-01

Roč. 456, č. 1 (2017), s. 151-162 ISSN 0022-247X Institutional support: RVO:67985556 Keywords : (M)-property * Choquet integral * Concave integral * Minimal atom * Monotone measure * Pan-integral Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.064, year: 2016 http://library.utia.cas.cz/separaty/2017/E/mesiar-0477091.pdf

Iris concavity, corneal biomechanics, and their correlations with ocular biometry in a cohort of 10- to 12-year-old UK school boys: baseline data.

Science.gov (United States)

Shah, Ameet; Low, Sancy; Garway-Heath, David F; Foster, Paul J; Barton, Keith

2014-04-17

Pigment dispersion syndrome is associated with iris concavity. This study investigated the prevalence of iris concavity, defined as a measurement of ≤-0.1 mm, in a cohort of 10- to 12-year-old boys, and explored the relationship between iris curvature and anterior segment biometry. Associations with corneal biomechanical parameters also were explored. A cohort of school boys (n = 96) was recruited from a local school. Anterior segment optical coherence tomography (AS-OCT) was performed under accommodative and nonaccommodative conditions, and iris curvature quantified. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured with the ocular response analyzer (ORA). Noncontact axial biometry was performed using laser interferometry. The prevalence of iris concavity was 24% on distance fixation, increasing to 65% on accommodation. Variables significantly associated with nonaccommodating iris curvature were lens vault (P = 0.02) and mean keratometry (P = 0.02). For both variables acting jointly, R(2) = 0.30. Variables associated significantly with accommodating iris curvature were anterior chamber depth (P = 0.009), lens vault (P = 0.049), and mean scleral spur angle (P Iris concavity was a common finding in this cohort and related to anterior segment biometric parameters. Further work is required to clarify whether anatomical differences exist between iris concavity seen in the adolescent eye and that found in adults with pigment dispersion syndrome. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Integration of polystyrene microlenses with both convex and concave profiles in a polymer-based microfluidic system

KAUST Repository

Fan, Yiqiang; Li, Huawei; Foulds, Ian G.

2013-01-01

This paper reports a new technique of fabricating polystyrene microlenses with both convex and concave profiles that are integrated in polymer-based microfluidic system. The polystyrene microlenses, or microlens array, are fabricated using the free

Verification of aspheric contact lens back surfaces.

Science.gov (United States)

Dietze, Holger H; Cox, Michael J; Douthwaite, William A

2003-08-01

To suggest a tolerance level for the degree of asphericity of aspheric rigid gas-permeable contact lenses and to find a simple method for its verification. Using existing tolerances for the vertex radius, tolerance limits for eccentricity and p values and were calculated. A keratometer-based method and a method based on sag measurements were used to measure the vertex radius and eccentricity of eight concave progressively aspheric surfaces and six concave ellipsoidal surfaces. The results were compared with a gold standard measurement made using a high-precision mechanical instrument (Form Talysurf). The suggested tolerance for eccentricity and p value and is +/-0.05. The keratometer method was very accurate and precise at measuring the vertex radius (mean deviation +/- SD from Talysurf results, -0.002 +/- 0.008 mm). The keratometer was more precise than and similar in accuracy to the sag method for measurement of asphericity (mean deviation of keratometer method results from Talysurf results, 0.017 +/- 0.018; mean deviation of sag method results from Talysurf results using five semichords, -0.016 +/- 0.032). Neither method was precise enough to verify the asphericity within the suggested tolerance. The keratometer can be efficiently used to verify the back vertex radius within its International Organization for Standardization tolerance and the back surface asphericity within an eccentricity/p value tolerance of +/-0.1. The method is poor for progressive aspheres with large edge blending zones. Deriving the eccentricity from sag measurements is a potential alternative if the mathematical description of the surface is known. The limiting factor of this method is the accuracy and precision of individual sag measurements.

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

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

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

2015-01-01

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 H_2PtCl_6 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. (paper)

Posterior all-pedicle screw instrumentation combined with multiple chevron and concave rib osteotomies in the treatment of adolescent congenital kyphoscoliosis.

Science.gov (United States)

Ayvaz, Mehmet; Olgun, Z Deniz; Demirkiran, H Gokhan; Alanay, Ahmet; Yazici, Muharrem

2014-01-01

complications were recorded. Deformity in both coronal and sagittal planes was analyzed for correction and maintenance of the correction in preoperative, postoperative, and follow-up radiographs. Patients' health-related quality of life was assessed using the SRS-22 questionnaire at the final follow-up. Eighteen patients met the inclusion criteria. Their average age was 13.6 years (range, 11-16 years). Chevron osteotomies were performed at apical segments (three to seven levels) and concave rib osteotomies at Cobb-to-Cobb (five to eight levels). No patient had preoperative cord compression because of the sharply angulated deformity or neurologic deficit. The average preoperative scoliosis was 66.0° (range, 31°-116°), 52.4° (range, 22°-85°) on flexibility X-rays, and became 24.9° (range, 12°-52°) postoperatively. The average preoperative global kyphosis (T2-T12) of 75.9° (range, 50°-106°) became 49.5° (range, 18°-66°). The average preoperative local kyphosis of 71.9° (range, 35°-114°) became 31.4° (range, -44° to 64°). The average intraoperative bleeding was 989 cc, surgical time was 292 minutes, and intraoperative transfusion was 2.3 units. The maximum PACU stay was overnight. There were no neurologic complications except one pneumothorax and one pneumonia. The average follow-up was 34.3 months. At follow-up, average scoliosis was 27.5° (range, 10°-50°), global kyphosis was 50.3° (range, 28°-73°), and local kyphosis was 36.9°(range, -36° to 58°). Performed on the last follow-up, the average scores for the five domains of SRS-22 were 4.3, 4.4, 4.2, 4.1, and 4.8 for function, pain, self-image, mental health, satisfaction, and total, respectively. Multiple chevron and concave rib osteotomies with posterior instrumentation provide an acceptable rate of deformity correction and maintenance of correction at 2 years with acceptable intraoperative bleeding, surgical time, postoperative morbidity, and rate of complications. It can be considered as an

Flow features that arise due to the interaction of a plane shock wave with concave profiles

CSIR Research Space (South Africa)

MacLucas, David A

2012-10-01

Full Text Available The focus of the author's thesis was the aerodynamic flow field that develops as a result of the interaction of a moving plane shock wave with concave profiles. In this presentation, he discusses some of the interesting flow phenomena that arise...

Double concave cesium encapsulation by two charged sumanenyl bowls

Energy Technology Data Exchange (ETDEWEB)

Spisak, Sarah N.; Wei, Zheng; Petrukhina, Marina A. [Department of Chemistry, University at Albany, State University of New York, Albany, NY (United States); Rogachev, Andrey Yu. [Department of Chemistry, Illinois Institute of Technology, Chicago, IL (United States); Amaya, Toru [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita (Japan); Hirao, Toshikazu [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita (Japan); The Institute of Scientific and Industrial Research, Osaka University (Japan)

2017-03-01

The controlled reaction of Na and Cs, two alkali metals of different ionic sizes and binding abilities, with sumanene (C{sub 21}H{sub 12}) affords a novel type of organometallic sandwich [Cs(C{sub 21}H{sub 11}{sup -}){sub 2}]{sup -}, which crystallized as a solvent-separated ion pair with a [Na(18-crown-6)(THF){sub 2}]{sup +} cation (where THF=tetrahydrofuran). The unprecedented double concave encapsulation of a metal ion by two bowl-shaped sumanenyl anions in [Cs(C{sub 21}H{sub 11}{sup -}){sub 2}]{sup -} was revealed crystallographically. Evaluation of bonding and energetics of the remarkable product was accomplished computationally (B2PLYP-D/TZVP/ZORA), providing insights into its formation. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Elective removal of convexo-concave Björk-Shiley valves.

Science.gov (United States)

Rajesh, P B; Smith, G H; Lawford, P V; Black, M M

1994-08-01

Replacement has been an accepted method for treating advanced cardiac valvular disease for more than 25 years. However, the perfect prosthesis has yet to be developed, judging by the number of devices available. A prosthesis that initially appears promising may cause problems in due course, and indeed some devices have been modified or withdrawn from clinical use. A notable example of a prosthetic valve that has give problems is the Björk-Shiley convexo-concave prosthesis, some models of which have undergone mechanical failure due to strut fracture. We report the elective removal of such a valve and the subsequent examination of the prosthesis. The results of this examination suggest that a policy of elective removal is justified.

Radiation Level Changes at RAM Package Surfaces

Energy Technology Data Exchange (ETDEWEB)

Opperman, Erich [Washington Savannah River Company; Hawk, Mark B [ORNL; Kapoor, Ashok [U.S. Department of Energy, Office of Packaging and Transportation; Natali, Ronald [R. B. Natali Consulting, Inc.

2010-01-01

This paper will explore design considerations required to meet the regulations that limit radiation level variations at external surfaces of radioactive material (RAM) packages. The radiation level requirements at package surfaces (e.g. TS-R-1 paragraphs 531 and 646) invoke not only maximum radiation levels, but also strict limits on the allowable increase in the radiation level during transport. This paper will explore the regulatory requirements by quantifying the amount of near surface movement and/or payload shifting that results in a 20% increase in the radiation level at the package surface. Typical IP-2, IP-3, Type A and Type B packaging and source geometries will be illustrated. Variations in surface radiation levels are typically the result of changes in the geometry of the surface due to an impact, puncture or crush event, or shifting and settling of radioactive contents.

Feedback-Capacity of Degraded Gaussian Vector BC using Directed Information and Concave Envelopes

OpenAIRE

Ramachandran, Viswanathan

2017-01-01

It is known that the capacity region of a two user physically degraded discrete memoryless (DM) broadcastchannel (BC) is not enlarged by feedback. An identical result holds true for a physically degraded Gaussian BC,established later using a variant of the Entropy Power Inequality (EPI). In this paper, we extend the latter resultto a physically degraded Gaussian Vector BC (PD-GVBC). However, the extension is not EPI based, but employs arecent result on the factorization of concave envelopes. ...

The improvement of GaN-based LED grown on concave nano-pattern sapphire substrate with SiO2 blocking layer

International Nuclear Information System (INIS)

Lin, Jyun-Hao; Huang, Shyh-Jer; Su, Yan-Kuin; Huang, Kai-Wen

2015-01-01

Highlights: • Concave nano-patterned sapphire substrates with SiO 2 blocking layer. • The IQE is almost two times larger than that of conventional one. • The EQE was extremely enhanced more than 100%. - Abstract: In contrast to convex nano-pattern sapphire substrates (NPSS), which are frequently used to fabricate high-quality nitride-based light-emitting diodes (LEDs), concave NPSS have been paid relatively less attention. In this study, a concave NPSS was fabricated, and its nitride epitaxial growth process was evaluated in a step by step manner. A SiO 2 layer was used to avoid nucleation over the sidewall and bottom of the nano-patterns to reduce dislocation reformation. Traditional LED structures were grown on the NPSS layer to determine its influence on device performance. X-ray diffraction, etched pit density, inverse leakage current, and internal quantum efficiency (IQE) results showed that dislocations and non-radiative recombination centers are reduced by the NPSS constructed with a SiO 2 blocking layer. An IQE twice that on a planar substrate was also achieved; such a high IQE significantly enhanced the external quantum efficiency of the resultant device. Taken together, the results demonstrate that the SiO 2 blocking layer proposed in this work can enhance the performance of LEDs.

The Björk-Shiley 70 degree convexo-concave prosthesis strut fracture problem (present state of information).

Science.gov (United States)

Ostermeyer, J; Horstkotte, D; Bennett, J; Huysmans, H; Lindblom, D; Olin, C; Orinius, E; Semb, G

1987-04-01

Between June 1980 and June 1983 4028 Björk-Shiley 70 degree convexo-concave prosthetic heart valves were distributed and implanted in Australia, Canada, Europe and South Africa. As of March 1986, a total of 52 outlet strut fractures (1.29%; 70% CL: 1.1%-1.5%) have been reported from 29 implant institutions in 12 countries. The majority (82.7%) occurred in Europe. Intervals between implantation and fracture were 13 days to 45.3 months (mean: 18.4 months; 70% CL: 16.6 months-20.1 months). The mortality rate after strut fracture was 78.7% (70% CL: 72.5%-84.9%). Upon stratification of the fracture by valve sizes and types it becomes evident that 75% (70% CL: 68.8%-81.2%) of all fractures are related to the sizes 29 mm to 33 mm (which virtually represent the same valve size) and predominantly to mitral valves (p less than 0.01). The large valves again have been stratified into two subsets, namely those fabricated from flanges originally machined as Björk-Shiley 60 degree convexo-concave valves (group I) and later produced valves machined initially to 70 degree specifications (group II). In group I the fracture rate was 5.2% (70% CL: 4.2%-6.2%) versus 1.6% (70% CL: 1.1%-2.1%) in group II (p less than 0.01), which identifies the group I 29 mm-33 mm Björk-Shiley 70 degree convexo-concave valves as the highest risk group for strut fracture. The rates are based upon all available information as of March 16, 1986.(ABSTRACT TRUNCATED AT 250 WORDS)

Surface-to-surface registration using level sets

DEFF Research Database (Denmark)

Hansen, Mads Fogtmann; Erbou, Søren G.; Vester-Christensen, Martin

2007-01-01

This paper presents a general approach for surface-to-surface registration (S2SR) with the Euclidean metric using signed distance maps. In addition, the method is symmetric such that the registration of a shape A to a shape B is identical to the registration of the shape B to the shape A. The S2SR...... problem can be approximated by the image registration (IR) problem of the signed distance maps (SDMs) of the surfaces confined to some narrow band. By shrinking the narrow bands around the zero level sets the solution to the IR problem converges towards the S2SR problem. It is our hypothesis...... that this approach is more robust and less prone to fall into local minima than ordinary surface-to-surface registration. The IR problem is solved using the inverse compositional algorithm. In this paper, a set of 40 pelvic bones of Duroc pigs are registered to each other w.r.t. the Euclidean transformation...

Analysis of the skin surface and inner structure around pores on the face.

Science.gov (United States)

Mizukoshi, Koji; Takahashi, Kazuhiro

2014-02-01

Facial pores do not appear to close again in old skin. Therefore, the tissue structure around the pore has been speculated to keep the pore open. To elucidate the reason for pore enlargement, we examined the relationship between the skin surface and inner skin structural characteristics in the same regions especially around the pore. Samples of the skin surface were obtained from the cheek and examined using a laser image processor to obtain three-dimensional (3D) data. The inner structure of the skin was analyzed using in vivo confocal laser scanning microscopy (CLSM). The conspicuous pore not only had a concave structure but also a discontinuous convex structure on the skin surface surrounding the pore. Furthermore, CLSM image indicated that the skin inner structure developed a discontinuous dermal papilla structure and isotropic dermal fiber structure. There were structural changes in the skin surface around conspicuous pores, including not only a concave structure but also a convex structure with skin inner structure changing. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Numerical investigation of mist/air impingement cooling on ribbed blade leading-edge surface.

Science.gov (United States)

Bian, Qingfei; Wang, Jin; Chen, Yi-Tung; Wang, Qiuwang; Zeng, Min

2017-12-01

The working gas turbine blades are exposed to the environment of high temperature, especially in the leading-edge region. The mist/air two-phase impingement cooling has been adopted to enhance the heat transfer on blade surfaces and investigate the leading-edge cooling effectiveness. An Euler-Lagrange particle tracking method is used to simulate the two-phase impingement cooling on the blade leading-edge. The mesh dependency test has been carried out and the numerical method is validated based on the available experimental data of mist/air cooling with jet impingement on a concave surface. The cooling effectiveness on three target surfaces is investigated, including the smooth and the ribbed surface with convex/concave columnar ribs. The results show that the cooling effectiveness of the mist/air two-phase flow is better than that of the single-phase flow. When the ribbed surfaces are used, the heat transfer enhancement is significant, the surface cooling effectiveness becomes higher and the convex ribbed surface presents a better performance. With the enhancement of the surface heat transfer, the pressure drop in the impingement zone increases, but the incremental factor of the flow friction is smaller than that of the heat transfer enhancement. Copyright © 2017 Elsevier Ltd. All rights reserved.

Wavelet Radiosity on Arbitrary Planar Surfaces

OpenAIRE

Holzschuch , Nicolas; Cuny , François; Alonso , Laurent

2000-01-01

Colloque avec actes et comité de lecture. internationale.; International audience; Wavelet radiosity is, by its nature, restricted to parallelograms or triangles. This paper presents an innovative technique enabling wavelet radiosity computations on planar surfaces of arbitrary shape, including concave contours or contours with holes. This technique replaces the need for triangulating such complicated shapes, greatly reducing the complexity of the wavelet radiosity algorithm and the computati...

Revisiting maximum-a-posteriori estimation in log-concave models: from differential geometry to decision theory

OpenAIRE

Pereyra, Marcelo

2016-01-01

Maximum-a-posteriori (MAP) estimation is the main Bayesian estimation methodology in many areas of data science such as mathematical imaging and machine learning, where high dimensionality is addressed by using models that are log-concave and whose posterior mode can be computed efficiently by using convex optimisation algorithms. However, despite its success and rapid adoption, MAP estimation is not theoretically well understood yet, and the prevalent view is that it is generally not proper ...

Fabrication and characterization of stable superhydrophobic surface with good friction-reducing performance on Al foil

Energy Technology Data Exchange (ETDEWEB)

Li, Peipei [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Chen, Xinhua, E-mail: xuc0374@hotmail.com [College of Chemistry and Chemical Engineering, Xuchang University, Xuchang 461000 (China); Yang, Guangbin; Yu, Laigui [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Zhang, Pingyu, E-mail: pingyu@henu.edu.cn [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China)

2014-05-01

Graphical abstract: A lotus-leaf-like hierarchical structure was successfully created on Al foil by a facile three-step solution–immersion method. As-obtained etched-immersed Al/STA rough surface contains interconnected convex–concave micro-structure and uniformly distributed nano-sheets that endow the surface with excellent superhydrophobicity (WCA: 164.2°; WSA: below 5°). Besides, the as-prepared etched-immersed Al/STA superhydrophobic surface on Al foil exhibits good friction-reducing ability and stable superhydrophobicity. - Highlights: • A stable superhydrophobic surface was created on aluminum foil by a facile three-step solution–immersion method. • A lotus-leaf-like hierarchical structure consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets has been constructed on the aluminum surface. • The superhydrophobic surfaces on aluminum substrate showing effective friction-reducing performance and self-cleaning ability. - Abstract: A lotus-leaf-like hierarchical structure with superhydrophobicity was created on Al foil by a facile three-step solution–immersion method involving etching in hydrochloric acid solution and immersing in hot water as well as surface-modification by stearic acid (denoted as STA). As-prepared etched-immersed Al/STA rough surface was characterized by means of scanning electron microscopy and X-ray photoelectron spectroscopy. Moreover, the water contact angles and water sliding angles of as-prepared etched-immersed Al/STA rough surface were measured, and the friction-reducing performance and self-cleaning ability of the as-prepared surface were also evaluated. Results indicate that the etched-immersed Al/STA rough surface consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets. Besides, it exhibits stable superhydrophobicity and good friction-reducing ability. Namely, it has a contact angle of water as high as 164.2° and a water sliding

Fabrication and characterization of stable superhydrophobic surface with good friction-reducing performance on Al foil

International Nuclear Information System (INIS)

Li, Peipei; Chen, Xinhua; Yang, Guangbin; Yu, Laigui; Zhang, Pingyu

2014-01-01

Graphical abstract: A lotus-leaf-like hierarchical structure was successfully created on Al foil by a facile three-step solution–immersion method. As-obtained etched-immersed Al/STA rough surface contains interconnected convex–concave micro-structure and uniformly distributed nano-sheets that endow the surface with excellent superhydrophobicity (WCA: 164.2°; WSA: below 5°). Besides, the as-prepared etched-immersed Al/STA superhydrophobic surface on Al foil exhibits good friction-reducing ability and stable superhydrophobicity. - Highlights: • A stable superhydrophobic surface was created on aluminum foil by a facile three-step solution–immersion method. • A lotus-leaf-like hierarchical structure consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets has been constructed on the aluminum surface. • The superhydrophobic surfaces on aluminum substrate showing effective friction-reducing performance and self-cleaning ability. - Abstract: A lotus-leaf-like hierarchical structure with superhydrophobicity was created on Al foil by a facile three-step solution–immersion method involving etching in hydrochloric acid solution and immersing in hot water as well as surface-modification by stearic acid (denoted as STA). As-prepared etched-immersed Al/STA rough surface was characterized by means of scanning electron microscopy and X-ray photoelectron spectroscopy. Moreover, the water contact angles and water sliding angles of as-prepared etched-immersed Al/STA rough surface were measured, and the friction-reducing performance and self-cleaning ability of the as-prepared surface were also evaluated. Results indicate that the etched-immersed Al/STA rough surface consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets. Besides, it exhibits stable superhydrophobicity and good friction-reducing ability. Namely, it has a contact angle of water as high as 164.2° and a water sliding

Molecular Dynamics Simulations of Slip on Curved Surfaces

Directory of Open Access Journals (Sweden)

Ross D.A.

2016-07-01

Full Text Available We present Molecular Dynamics (MD simulations of liquid water confined within nanoscale geometries, including slit-like and cylindrical graphitic pores. These equilibrium results are used for calculating friction coefficients, which in turn can be used to calculate slip lengths. The slip length is a material property independent of the fluid flow rate. It is therefore a better quantity for study than the fluid velocity at the wall, also known as the slip velocity. Once the slip length has been found as a function of surface curvature, it can be used to parameterise Lattice Boltzmann (LB simulations. These larger scale simulations are able to tell us about how fluid transport is affected by slip in complex geometries; not just limited to single pores. Applications include flow and transport in nano-porous engine valve deposits and gas shales. The friction coefficient is found to be a function of curvature and is higher for fluid on convex surfaces and lower for concave surfaces. Both concave and convex surfaces approach the same value of the friction coefficient, which is constant above some critical radius of curvature, here found to be 7.4 ± 2.9 nm. The constant value of the friction coefficient is 10,000 ± 600 kg m−2 s−1, which is equivalent to a slip length of approximately 67 ± 4 nm.

Surface topography of a palladium cathode after electrolysis in heavy water

International Nuclear Information System (INIS)

Silver, D.S.; Dash, J.; Keefe, P.S.

1993-01-01

Electrolysis was performed with a palladium cathode and an electrolyte containing both hydrogen and deuterium ions. The cathode bends toward the anode during this process. Examination of both the concave and the convex surfaces with the scanning electron microscope, scanning tunneling microscope, and atomic force microscope shows unusual surface characteristics. Rimmed craters with faceted crystals inside and multitextural surfaces were observed on an electrolyzed palladium cathode but not on palladium that has not been electrolyzed. 9 refs., 9 figs

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

Science.gov (United States)

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.

Electron optical characteristics of a concave electrostatic electron mirror for a scanning electron microscope

International Nuclear Information System (INIS)

Hamarat, R.T.; Witzani, J.; Hoerl, E.M.

1984-08-01

Numerical computer calculations are used to explore the design characteristics of a concave electrostatic electron mirror for a mirror attachment for a conventional scanning electron microscope or an instrument designed totally as a scanning electron mirror microscope. The electron paths of a number of set-ups are calculated and drawn graphically in order to find the optimum shape and dimensions of the mirror geometry. This optimum configuration turns out to be the transition configuration between two cases of electron path deflection, towards the optical axis of the system and away from it. (Author)

Inference from concave stochastic frontiers and the covariance of firm efficiency measures across firms

International Nuclear Information System (INIS)

Dashti, Imad

2003-01-01

This paper uses a Bayesian stochastic frontier model to obtain confidence intervals on firm efficiency measures of electric utilities rather than the point estimates reported in most previous studies. Results reveal that the stochastic frontier model yields imprecise measures of firm efficiency. However, the application produces much more precise inference on pairwise efficiency comparisons of firms due to a sometimes strong positive covariance of efficiency measures across firms. In addition, we examine the sensitivity to functional form by repeating the analysis for Cobb-Douglas, translog and Fourier frontiers, with and without imposing monotonicity and concavity

Surface-Level Diversity and Decision-Making in Groups: When Does Deep-Level Similarity Help?

OpenAIRE

2006-01-01

Abstract We examined how surface-level diversity (based on race) and deep-level similarities influenced three-person decision-making groups on a hidden-profile task. Surface-level homogeneous groups perceived their information to be less unique and spent less time on the task than surface-level diverse groups. When the groups were given the opportunity to learn about their deep-level similarities prior to t...

Etude aerodynamique d'un jet turbulent impactant une paroi concave

Science.gov (United States)

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

A reappraisal of pediatric thoracic surface anatomy.

Science.gov (United States)

Fischer, Nicholas J; Morreau, Jonty; Sugunesegran, Ramanen; Taghavi, Kiarash; Mirjalili, S Ali

2017-09-01

Accurate knowledge of surface anatomy is fundamental to safe clinical practice. A paucity of evidence in the literature regarding thoracic surface anatomy in children was identified. The associations between surface landmarks and internal structures were meticulously analyzed by reviewing high quality computed tomography (CT) images of 77 children aged from four days to 12 years. The results confirmed that the sternal angle is an accurate surface landmark for the azygos-superior vena cava junction in a plane through to the level of upper T4 from birth to age four, and to lower T4 in older children. The concavity of the aortic arch was slightly below this plane and the tracheal and pulmonary artery bifurcations were even lower. The cardiac apex was typically at the 5 th intercostal space (ICS) from birth to age four, at the 4 th ICS and 5 th rib in 4-12 year olds, and close to the midclavicular line at all ages. The lower border of the diaphragm was at the level of the 6 th or 7 th rib at the midclavicular line, the 7 th ICS and 8 th rib at the midaxillary line, and the 11 th thoracic vertebra posteriorly. The domes of the diaphragm were generally flatter and lower in children, typically only one rib level higher than its anterior level at the midclavicular line. Diaphragm apertures were most commonly around the level of T9, T10, and T11 for the IVC, esophagus and aorta, respectively. This is the first study to provide an evidence-base for thoracic surface anatomy in children. Clin. Anat. 30:788-794, 2017. © 2017Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

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

Directory of Open Access Journals (Sweden)

Ralph C A Rippe

Full Text Available 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.

Facile synthesis and electrochemiluminescence application of concave trisoctahedral Pd@Au core-shell nanocrystals bound by {331} high-index facets.

Science.gov (United States)

Zhang, Ling; Niu, Wenxin; Li, Zhiyuan; Xu, Guobao

2011-10-07

Concave trisoctahedral (TOH) Pd@Au core-shell nanocrystals bound by {331} facets have been synthesized for the first time. Pd nanocubes and cetyltrimethylammonium chloride were used as the structure-directing cores and capping agents, respectively. Their optical and electrocatalytic properties were investigated. This journal is © The Royal Society of Chemistry 2011

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

Science.gov (United States)

Sandri, P.

2017-12-01

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.

Effect of surface conditions on blast wave propagation

International Nuclear Information System (INIS)

Song, Seung Ho; Li, Yi Bao; Lee, Chang Hoon; Choi, Jung Il

2016-01-01

We performed numerical simulations of blast wave propagations on surfaces by solving axisymmetric two-dimensional Euler equations. Assuming the initial stage of fireball at the breakaway point after an explosion, we investigated the effect of surface conditions considering surface convex or concave elements and thermal conditions on blast wave propagations near the ground surface. Parametric studies were performed by varying the geometrical factors of the surface element as well as thermal layer characteristics. We found that the peak overpressure near the ground zero was increased due to the surface elements, while modulations of the blast wave propagations were limited within a region for the surface elements. Because of the thermal layer, the precursor was formed in the propagations, which led to the attenuation of the peak overpressure on the ground surface

STM imaging of electronic waves on the surface of Bi2Te3: topologically protected surface states and hexagonal warping effects

Energy Technology Data Exchange (ETDEWEB)

Alpichshev, Zhanybek; /SIMES, Stanford /SLAC /Stanford U., Phys. Dept.; Analytis, J.G.; /SIMES, Stanford /SLAC /Stanford U., Phys. Dept.; Chu, J.-H.; Fisher, I.R.; /SIMES, Stanford /SLAC /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.; Chen, Y.L.; /SIMES, Stanford /SLAC /Stanford U., Phys. Dept.; Shen, Z.X.; /SIMES, Stanford /SLAC /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.; Fang, A.; /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.; Kapitulnik, A.; /SIMES, Stanford /SLAC /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

2010-06-02

Scanning tunneling spectroscopy studies on high-quality Bi{sub 2}Te{sub 3} crystals exhibit perfect correspondence to ARPES data, hence enabling identification of different regimes measured in the local density of states (LDOS). Oscillations of LDOS near a step are analyzed. Within the main part of the surface band oscillations are strongly damped, supporting the hypothesis of topological protec- tion. At higher energies, as the surface band becomes concave, oscillations appear which disperse with a particular wave-vector that may result from an unconventional hexagonal warping term.

Locally Different Endothelial Nitric Oxide Synthase Protein Levels in Ascending Aortic Aneurysms of Bicuspid and Tricuspid Aortic Valve

Directory of Open Access Journals (Sweden)

Salah A. Mohamed

2012-01-01

Full Text Available Aims. Dysregulated expression of the endothelial nitric oxide synthase (eNOS is observed in aortic aneurysms associated with bicuspid aortic valve (BAV. We determined eNOS protein levels in various areas in ascending aortic aneurysms. Methods and Results. Aneurysmal specimens were collected from 19 patients, 14 with BAV and 5 with tricuspid aortic valve (TAV. ENOS protein levels were measured in the outer curve (convexity, the opposite side (concavity, the distal and above the sinotubular junction (proximal aneurysm. Cultured aortic cells were treated with NO synthesis inhibitor L-NAME and the amounts of 35 apoptosis-related proteins were determined. In patients with BAV, eNOS levels were significantly lower in the proximal aorta than in the concavity and distal aorta. ENOS protein levels were also lower in the convexity than in the concavity. While the convexity and distal aorta showed similar eNOS protein levels in BAV and TAV patients, levels were higher in TAV proximal aorta. Inhibition of NO synthesis in aneurysmal aortic cells by L-NAME led to a cytosolic increase in the levels of mitochondrial serine protease HTRA2/Omi. Conclusion. ENOS protein levels were varied at different areas of the aneurysmal aorta. The dysregulation of nitric oxide can lead to an increase in proapoptotic HTRA2/Omi.

Longitudinal study of iris concavity, corneal biomechanics, and correlations to ocular biometry in a cohort of 10- to 12-year-old UK schoolboys: 2-year follow-up data.

Science.gov (United States)

Shah, Ameet; Lascaratos, Gerassimos; Garway-Heath, David F; Foster, Paul J; Barton, Keith

2014-06-10

To explore changes in iris curvature over a 2-year period. To investigate associations between iris curvature and ocular biometric parameters. To explore relationships between a number of nonocular measurements and ocular biometric parameters. Schoolboys enrolled 2 years previously were invited to return for anterior segment optical coherence tomography, corneal hysteresis (CH), corneal resistance factor (CRF), and axial biometric measurements. Refractive error was assessed and measures of height, weight, waist circumference, digit ratio, and percentage body fat taken. Mean spherical equivalent refraction reduced by 0.76 diopters and mean iris concavity, defined as a measurement of less than or equal to -0.1 mm, increased by 0.018 mm at distance fixation and 0.04 mm on accommodation. Compared with 2 years previously, the prevalence of iris concavity increased from 24% to 32% on distance fixation and from 65% to 84% on accommodation. Variables significantly associated with nonaccommodating iris curvature were anterior chamber depth (ACD, P = 0.029) and mean scleral spur angle (P = 0.0001). Variables significantly associated with accommodating iris curvature were ACD (P = 0.02), lens vault (P = 0.047), and scleral spur angle (P Iris concavity was more prevalent in this cohort of schoolboys than 2 years earlier. The degree of concavity remains related to ACD and lens vault. The association between spur-to-spur distance and CH was similar at baseline and after 2 years. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Topographic characterization of nanostructures on curved polymer surfaces

DEFF Research Database (Denmark)

Feidenhans'l, Nikolaj Agentoft; Petersen, Jan C.; Taboryski, Rafael J.

2014-01-01

The availability of portable instrumentation for characterizing surface topography on the micro- and nanometer scale is very limited. Particular the handling of curved surfaces, both concave and convex, is complicated or not possible on current instrumentation. However, the currently growing use...... method with a portable instrument that can be used in a production environment, and topographically characterize nanometer-scale surface structures on both flat and curved surfaces. To facilitate the commercialization of injection moulded polymer parts featuring nanostructures, it is pivotal...... of injection moulding of polymer parts featuring nanostructured surfaces, requires an instrument that can characterize these structures to ensure replication-confidence between master structure and replicated polymer parts. This project concerns the development of a metrological traceable quality control...

Three-dimensional imaging of a complex concaved cuboctahedron copper sulfide crystal by x-ray nanotomography

International Nuclear Information System (INIS)

Chen Jie; Tian Jinping; Li Wenjie; Tian Yangchao; Wu Chunyan; Yu Shuhong

2008-01-01

By combining Fresnel zone-plate based transmission x-ray microscopy with computed tomography, the nanoscale features in materials with complex shapes can be imaged using synchrotron radiation. The tomographic data sets of a complex copper sulfide crystal were acquired in the angle range ±70 deg. at photon energy of 8.0 keV and then were reconstructed by a standard filtered-back-projection algorithm. This experiment shows the quantifiable three-dimensional information of the copper sulfide crystal, which offers a complete understanding of the concaved cuboctahedron structure with 14 faces comprising of six squares and eight triangles

Fabrication of agarose concave petridish for 3D-culture microarray method for spheroids formation of hepatic cells.

Science.gov (United States)

Zhang, Binbin; Li, Yang; Wang, Gaoshang; Jia, Zhidong; Li, Haiyan; Peng, Qing; Gao, Yi

2018-04-19

Liver is one of the most important organ in the body. But there are many limitations about liver transplantation for liver failure. It is quite important to develop the xenogeneic biological liver for providing an alternation to transplantation or liver regeneration. In this paper, we proposed a method to construct a novel kind of agarose 3D-culture concave microwell array for spheroids formation of hepatic cells. Using the 3D printing method, the microwell array was fabricated with an overall size of 6.4 mm × 6.4 mm, containing 121 microwells with 400 μm width/400 μm thickness. By exploiting the Polydimethylsiloxane (PDMS) membranes as a bridge, we finally fabricated the agarose one. We co-cultured three types of liver cells with bionics design in the microwell arrays. Using the methods described above, the resulting co-formed hepatocyte spheroids maintained the high viability and stable liver-specific functions. This engineered agarose concave microwell array could be a potentially useful tool for forming the elements for biological liver support. After developing the complete system, we also would consider to scale up the application of this system. It will be not only applied to the therapy of human organ damage, but also to the development of disease models and drug screening models.

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

Science.gov (United States)

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

Studies on the zeros of Bessel functions and methods for their computation: 2. Monotonicity, convexity, concavity, and other properties

Science.gov (United States)

Kerimov, M. K.

2016-07-01

This work continues the study of real zeros of first- and second-kind Bessel functions and Bessel general functions with real variables and orders begun in the first part of this paper (see M.K. Kerimov, Comput. Math. Math. Phys. 54 (9), 1337-1388 (2014)). Some new results concerning such zeros are described and analyzed. Special attention is given to the monotonicity, convexity, and concavity of zeros with respect to their ranks and other parameters.

太阳能技术在“绿色凹宅”中的应用%Application of Solar Energy Technology in Green Concave House

Institute of Scientific and Technical Information of China (English)

莫理莉

2014-01-01

This paper introduced the application of solar energy technology in green concave house.The grid-connection photovoltaic power generation was used,which sent the redundant power back to the power network.The photovoltaic solar-thermal integrated solar panels provided the output of electricity and daily at the same time.The smart home system provided the comfortable environment for green concave house.The green concave house is a successful and low energy consumption example,which could provide references for the area of abundant solar energy and dispersal residence.%介绍了太阳能技术在“绿色凹宅”中的应用。采用的并网型太阳能光伏发电系统，当有余电时可回馈电网。铺设的光伏光热一体化太阳能板，在电力输出的同时提供生活热水。智能家居系统给“绿色凹宅”提供舒适的环境。“绿色凹宅”是一个比较成功的环保、低能耗的住宅实例，对太阳能资源丰富而又居住分散的地区有很好的借鉴意义。

Approximal morphology as predictor of approximal caries in primary molar teeth

DEFF Research Database (Denmark)

Cortes, A; Martignon, S; Qvist, V

2018-01-01

consent was given, participated. Upper and lower molar teeth of one randomly selected side received a 2-day temporarily separation. Bitewing radiographs and silicone impressions of interproximal area (IPA) were obtained. One-year procedures were repeated in 52 children (84%). The morphology of the distal...... surfaces of the first molar teeth and the mesial surfaces on the second molar teeth (n=208) was scored from the occlusal aspect on images from the baseline resin models resulting in four IPA variants: concave-concave; concave-convex; convex-concave, and convex-convex. Approximal caries on the surface...

Sea level and turbidity controls on mangrove soil surface elevation change

Science.gov (United States)

Lovelock, Catherine E.; Fernanda Adame, Maria; Bennion, Vicki; Hayes, Matthew; Reef, Ruth; Santini, Nadia; Cahoon, Donald R.

2015-01-01

Increases in sea level are a threat to seaward fringing mangrove forests if levels of inundation exceed the physiological tolerance of the trees; however, tidal wetlands can keep pace with sea level rise if soil surface elevations can increase at the same pace as sea level rise. Sediment accretion on the soil surface and belowground production of roots are proposed to increase with increasing sea level, enabling intertidal habitats to maintain their position relative to mean sea level, but there are few tests of these predictions in mangrove forests. Here we used variation in sea level and the availability of sediments caused by seasonal and inter-annual variation in the intensity of La Nina-El Nino to assess the effects of increasing sea level on surface elevation gains and contributing processes (accretion on the surface, subsidence and root growth) in mangrove forests. We found that soil surface elevation increased with mean sea level (which varied over 250 mm during the study) and with turbidity at sites where fine sediment in the water column is abundant. In contrast, where sediments were sandy, rates of surface elevation gain were high, but not significantly related to variation in turbidity, and were likely to be influenced by other factors that deliver sand to the mangrove forest. Root growth was not linked to soil surface elevation gains, although it was associated with reduced shallow subsidence, and therefore may contribute to the capacity of mangroves to keep pace with sea level rise. Our results indicate both surface (sedimentation) and subsurface (root growth) processes can influence mangrove capacity to keep pace with sea level rise within the same geographic location, and that current models of tidal marsh responses to sea level rise capture the major feature of the response of mangroves where fine, but not coarse, sediments are abundant.

Evaluation of concave dose distributions created using an inverse planning system

International Nuclear Information System (INIS)

Hunt, Margie A.; Hsiung, C.-Y.; Spirou, Spirodon V.; Chui, C.-S.; Amols, Howard I.; Ling, Clifton C.

2002-01-01

Purpose: To evaluate and develop optimum inverse treatment planning strategies for the treatment of concave targets adjacent to normal tissue structures. Methods and Materials: Optimized dose distributions were designed using an idealized geometry consisting of a cylindrical phantom with a concave kidney-shaped target (PTV) and cylindrical normal tissues (NT) placed 5-13 mm from the target. Targets with radii of curvature from 1 to 2.75 cm were paired with normal tissues with radii between 0.5 and 2.25 cm. The target was constrained to a prescription dose of 100% and minimum and maximum doses of 95% and 105% with relative penalties of 25. Maximum dose constraint parameters for the NT varied from 10% to 70% with penalties from 10 to 1000. Plans were evaluated using the PTV uniformity index (PTV D max /PTV D 95 ) and maximum normal tissue doses (NT D max /PTV D 95 ). Results: In nearly all situations, the achievable PTV uniformity index and the maximum NT dose exceeded the corresponding constraints. This was particularly true for small PTV-NT separations (5-8 mm) or strict NT dose constraints (10%-30%), where the achievable doses differed from the requested by 30% or more. The same constraint parameters applied to different PTV-NT separations yielded different dose distributions. For most geometries, a range of constraints could be identified that would lead to acceptable plans. The optimization results were fairly independent of beam energy and radius of curvature, but improved as the number of beams increased, particularly for small PTV-NT separations or strict dose constraints. Conclusion: Optimized dose distributions are strongly affected by both the constraint parameters and target-normal tissue geometry. Standard site-specific constraint templates can serve as a starting point for optimization, but the final constraints must be determined iteratively for individual patients. A strategy whereby NT constraints and penalties are modified until the highest

Self-centring technique for fibre optic microlens mounting using a concave cone-etched fibre

International Nuclear Information System (INIS)

Demagh, Nacer-Eddine; Guessoum, Assia; Zegari, Rabah; Gharbi, Tijani

2011-01-01

Several techniques of centring a microlens onto the fibre optic end face are studied. In most of them, microsphere lenses are centred with the aid of high-accuracy micro-positioners. This process is complicated with regard to the difficulty in manipulating microsphere lenses. In this paper, a simple and accurate self-centring method for mounting microsphere lenses using a concave cone etched fibre (Demagh et al 2006 Meas. Sci. Technol. 17 119–22) is described. This technique allows the centring of a wide variety of microlens radii, typically 7 µm to over 24 µm. The proposed process, however, is not affected by any spatial positioning control of microspheres. In over 85% of the attempts, the microsphere lenses were centred on the fibre axis to within 0.12 µm

Surface core-level shifts for simple metals

DEFF Research Database (Denmark)

Aldén, Magnus; Skriver, Hans Lomholt; Johansson, Börje

1994-01-01

screening, whereby a SCLS becomes equivalent to the surface segregation energy of a core-ionized atom, a quantity we obtain by separate bulk and surface impurity calculations. The results are in good agreement with experiment in most of those cases where the data originates from single-crystal measurements....... We discuss the surface shifts of the electrostatic potentials and the band centers in order to trace the microscopic origin of the SCLS in the simple metals and find that the anomalous subsurface core-level shifts in beryllium are caused by charge dipoles, which persist several layers into the bulk...

Effects of Topography and Surface Soil Cover on Erosion for Mining Reclamation: The Experimental Spoil Heap at El Machorro Mine (Central Spain)

OpenAIRE

Martín Moreno, Cristina; Martín Duque, J. F.; Nicolau, J. M.; Hernando, N.; Sanz, M. A.; Sánchez Castillo, L.

2013-01-01

Mining reclamation tries to reduce environmental impacts, including accelerated runoff, erosion and sediment load in the nearby fluvial networks and their ecosystems. This study compares the effects of topography and surface soil cover on erosion on man-made slopes coming from surface mining reclamation in Central Spain. Two topographic profiles, linear and concave, with two surface soil covers, subsoil and topsoil, were monitored for two hydrologic years. Sediment load, rill development and ...

FJ-2207 measuring instrument detection pipe surface a level of pollution method

International Nuclear Information System (INIS)

Wang Jiangong

2010-01-01

On the pipe surface contamination were detected α level of pollution is a frequently encountered dose-detection work. Because the pipeline surface arc, while the measuring probe for the plane, which for accurate measurement difficult. In this paper, on the FJ-2207-type pipe surface contamination measuring instrument measuring pollution levels in the α method was studied. Introduced the FJ-2207 measuring instrument detection pipe surface α pollution levels. Studied this measuring instrument on the same sources of surface, plane α level of radioactivity measured differences in the results obtained control of the apparatus when the direct measurement of the surface correction factor, and gives 32-216 specifications commonly used pipe direct measurement of the amendment factor. Convenient method, test results are reliable for the accurate measurement of pipe pollution levels in the surface of α as a reference and learning. (authors)

Level crossing analysis of growing surfaces

International Nuclear Information System (INIS)

Shahbazi, F; Sobhanian, S; Tabar, M Reza Rahimi; Khorram, S; Frootan, G R; Zahed, H

2003-01-01

We investigate the average frequency of positive slope ν + α , crossing the height α = h - h-bar in the surface growing processes. The exact level crossing analysis of the random deposition model and the Kardar-Parisi-Zhang equation in the strong coupling limit before creation of singularities is given

Self-Similar Solutions of Rényi’s Entropy and the Concavity of Its Entropy Power

Directory of Open Access Journals (Sweden)

Agapitos N. Hatzinikitas

2015-08-01

Full Text Available We study the class of self-similar probability density functions with finite mean and variance, which maximize Rényi’s entropy. The investigation is restricted in the Schwartz space S(Rd and in the space of l-differentiable compactly supported functions Clc (Rd. Interestingly, the solutions of this optimization problem do not coincide with the solutions of the usual porous medium equation with a Dirac point source, as occurs in the optimization of Shannon’s entropy. We also study the concavity of the entropy power in Rd with respect to time using two different methods. The first one takes advantage of the solutions determined earlier, while the second one is based on a setting that could be used for Riemannian manifolds.

Ab initio surface core-level shifts and surface segregation energies

DEFF Research Database (Denmark)

Aldén, Magnus; Skriver, Hans Lomholt; Johansson, Börje

1993-01-01

We have calculated the surface core-level energy shifts of the 4d and 5d transition metals by means of local-density theory and a Green’s-function technique based on the linear muffin-tin orbitals method. Final-state effects are included by treating the core-ionized atom as an impurity located in...

Influence of surface microstructure and chemistry on osteoinduction and osteoclastogenesis by biphasic calcium phosphate discs

Directory of Open Access Journals (Sweden)

NL Davison

2015-06-01

Full Text Available It has been reported that surface microstructural dimensions can influence the osteoinductivity of calcium phosphates (CaPs, and osteoclasts may play a role in this process. We hypothesised that surface structural dimensions of ≤ 1 μm trigger osteoinduction and osteoclast formation irrespective of macrostructure (e.g., concavities, interconnected macropores, interparticle space or surface chemistry. To test this, planar discs made of biphasic calcium phosphate (BCP: 80 % hydroxyapatite, 20 % tricalcium phosphate were prepared with different surface structural dimensions – either ~ 1 μm (BCP1150 or ~ 2-4 μm (BCP1300 – and no macropores or concavities. A third material was made by sputter coating BCP1150 with titanium (BCP1150Ti, thereby changing its surface chemistry but preserving its surface structure and chemical reactivity. After intramuscular implantation in 5 dogs for 12 weeks, BCP1150 formed ectopic bone in 4 out of 5 samples, BCP1150Ti formed ectopic bone in 3 out of 5 samples, and BCP1300 formed no ectopic bone in any of the 5 samples. In vivo, large multinucleated osteoclast-like cells densely colonised BCP1150, smaller osteoclast-like cells formed on BCP1150Ti, and osteoclast-like cells scarcely formed on BCP1300. In vitro, RAW264.7 cells cultured on the surface of BCP1150 and BCP1150Ti in the presence of osteoclast differentiation factor RANKL (receptor activator for NF-κB ligand proliferated then differentiated into multinucleated osteoclast-like cells with positive tartrate resistant acid phosphatase (TRAP activity. However, cell proliferation, fusion, and TRAP activity were all significantly inhibited on BCP1300. These results indicate that of the material parameters tested – namely, surface microstructure, macrostructure, and surface chemistry – microstructural dimensions are critical in promoting osteoclastogenesis and triggering ectopic bone formation.

Research on near-surface disposal of very low level radioactive waste

International Nuclear Information System (INIS)

Wang Shaowei; Yue Huiguo; Hou Jie; Chen Haiying; Zuo Rui; Wang Jinsheng

2012-01-01

Radioactive waste disposal is one of the most sensitive environmental problems to control and solve. As the arriving of decommissioning of early period nuclear facilities in China, large amounts of very low level radioactive waste will be produced inevitably. The domestic and abroad definitions about very low level radioactive waste and its disposal were introduced, and then siting principles of near-surface disposal of very low level radioactive waste were discussed. The near- surface disposal siting methods of very low level radioactive waste were analyzed from natural and geographical conditions assessment, geological conditions analysis, hydrogeological conditions analysis, geological hazard assessment and radioactive background investigation; the near-surface disposal sites'natural barriers of very low level radioactive waste were analyzed from the crustal structure and physico-chemical characteristics, the dynamics characteristics of groundwater, the radionuclide adsorption characteristics of natural barriers and so on; the near-surface disposal sites' engineered barriers of very low level radioactive waste were analyzed from the repository design, the repository barrier materials selection and so on. Finally, the improving direction of very low level radioactive waste disposal was proposed. (authors)

Optimization of radiotherapy to target volumes with concave outlines: target-dose homogenization and selective sparing of critical structures by constrained matrix inversion

Energy Technology Data Exchange (ETDEWEB)

Colle, C; Van den Berge, D; De Wagter, C; Fortan, L; Van Duyse, B; De Neve, W

1995-12-01

The design of 3D-conformal dose distributions for targets with concave outlines is a technical challenge in conformal radiotherapy. For these targets, it is impossible to find beam incidences for which the target volume can be isolated from the tissues at risk. Commonly occurring examples are most thyroid cancers and the targets located at the lower neck and upper mediastinal levels related to some head and neck. A solution to this problem was developed, using beam intensity modulation executed with a multileaf collimator by applying a static beam-segmentation technique. The method includes the definition of beam incidences and beam segments of specific shape as well as the calculation of segment weights. Tests on Sherouse`s GRATISTM planning system allowed to escalate the dose to these targets to 65-70 Gy without exceeding spinal cord tolerance. Further optimization by constrained matrix inversion was investigated to explore the possibility of further dose escalation.

Surface Chloride Levels in Colorado Structural Concrete

Science.gov (United States)

2018-01-01

This project focused on the chloride-induced corrosion of reinforcing steel in structural concrete. The primary goal of this project is to analyze the surface chloride concentration level of the concrete bridge decks throughout Colorado. The study in...

Automatic Measurement of Low Level Contamination on Concrete Surfaces

International Nuclear Information System (INIS)

Tachibana, M.; Itoh, H.; Shimada, T.; Yanagihara, S.

2002-01-01

Automatic measurement of radioactivity is necessary for considering cost effectiveness in final radiological survey of building structures in decommissioning nuclear facilities. The RAPID (radiation measuring pilot device for surface contamination) was developed to be applied to automatic measurement of low level contamination on concrete surfaces. The RAPID has a capability to measure contamination with detection limit of 0.14 Bq/cm2 for 60Co in 30 seconds of measurement time and its efficiency is evaluated to be 5 m2/h in a normal measurement option. It was confirmed that low level contamination on concrete surfaces could be surveyed by the RAPID efficiently compared with direct measurement by workers through its actual application

Photo-responsive surface topology in chiral nematic media

Science.gov (United States)

Liu, Danqing; Bastiaansen, Cees W. M.; Toonder, Jaap. M. J.; Broer, Dirk J.

2012-03-01

We report on the design and fabrication of 'smart surfaces' that exhibit dynamic changes in their surface topology in response to exposure to light. The principle is based on anisotropic geometric changes of a liquid crystal network upon a change of the molecular order parameter. The photomechanical property of the coating is induced by incorporating an azobenzene moiety into the liquid crystal network. The responsive surface topology consists of regions with two different types of molecular order: planar chiral-nematic areas and homeotropic. Under flood exposure with 365 nm light the surfaces deform from flat to one with a surface relief. The height of the relief structures is of the order of 1 um corresponding to strain difference of around 20%. Furthermore, we demonstrate surface reliefs can form either convex or concave structures upon exposure to UV light corresponding to the decrease or increase molecular order parameter, respectively, related to the isomeric state of the azobenzene crosslinker. The reversible deformation to the initial flat state occurs rapidly after removing the light source.

Dynamics of gas-surface interactions atomic-level understanding of scattering processes at surfaces

CERN Document Server

Díez Muniño, Ricardo

2013-01-01

This book gives a representative survey of the state of the art of research on gas-surface interactions. It provides an overview of the current understanding of gas surface dynamics and, in particular, of the reactive and non-reactive processes of atoms and small molecules at surfaces. Leading scientists in the field, both from the theoretical and the experimental sides, write in this book about their most recent advances. Surface science grew as an interdisciplinary research area over the last decades, mostly because of new experimental technologies (ultra-high vacuum, for instance), as well as because of a novel paradigm, the ‘surface science’ approach. The book describes the second transformation which is now taking place pushed by the availability of powerful quantum-mechanical theoretical methods implemented numerically. In the book, experiment and theory progress hand in hand with an unprecedented degree of accuracy and control. The book presents how modern surface science targets the atomic-level u...

Surface drainage in leveled land: Implication of slope

Directory of Open Access Journals (Sweden)

Antoniony S. Winkler

Full Text Available ABSTRACT In the lowlands of Rio Grande do Sul, land leveling is mostly carried out with no slope for the purpose of rice production. In this environment, soils with a low hydraulic conductivity are predominant owing to the presence of a practically impermeable B-horizon near the surface. Land leveling leads to soil accommodation resulting in the formation of depressions where water accumulates after heavy rainfalls, subsequently leading to problems with crops implanted in succession to rice, such as soybeans. The objective of this research was to quantify the areas and volumes of water accumulation in soil as a function of the slope of land leveling. Five typical leveled lowland areas were studied as a part of this research. The original areas presented slopes of 0, 0.20, 0.25, 0.28 and 0.40%, which were used to generate new digital elevation models with slopes between 0 and 0.5%. These newly generated digital models were used to map the depressions with surface water storage. In conclusion, land leveling with slopes higher than 0.1% is recommended to minimize problems with superficial water storage in rice fields.

Decommissioning high-level waste surface facilities

International Nuclear Information System (INIS)

1978-04-01

The protective storage, entombment and dismantlement options of decommissioning a High-Level Waste Surface Facility (HLWSF) was investigated. A reference conceptual design for the facility was developed based on the designs of similar facilities. State-of-the-art decommissioning technologies were identified. Program plans and cost estimates for decommissioning the reference conceptual designs were developed. Good engineering design concepts were on the basis of this work identified

Surface core level shifts of clean and oxygen covered Ir(111)

Energy Technology Data Exchange (ETDEWEB)

Bianchi, M; Cassese, D; Cavallin, A; Comin, R; Orlando, F; Postregna, L [Universita degli Studi di Trieste, Via A Valerio 2, 34127, Trieste (Italy); Golfetto, E; Baraldi, A [Dipartimento di Fisica e CENMAT, Universita degli Studi di Trieste, Via A Valerio 2, 34127, Trieste (Italy); Lizzit, S [Sincrotrone Trieste S.C.p.A., S.S. 14 Km 163.5, 34012 Trieste (Italy)], E-mail: alessandro.baraldi@elettra.trieste.it

2009-06-15

We present the results of high resolution core level photoelectron spectroscopy employed to investigate the electronic structure of clean and oxygen covered Ir(111) surface. Ir 4f{sub 7/2} core level spectra are shown to be very sensitive to the local atomic environment. For the clean surface we detected two distinct components shifted by 550 meV, originated by surface and bulk atoms. The larger Gaussian width of the bulk component is explained as due to experimentally unresolved subsurface components. In order to determine the relevance of the phonon contribution we examined the thermal behaviour of the core level lineshape using the Hedin-Rosengren theory. From the phonon-induced spectral broadening we found the Debye temperature of bulk and surface atoms to be 298 and 181 K, respectively, which confirms the softening of the vibrational modes at the surface. Oxygen adsorption leads to the appearance of new surface core level components at -200 meV and +230 meV, which are interpreted as due to first-layer Ir atoms differently coordinated with oxygen. The coverage dependence of these components demonstrates that the oxygen saturation corresponds to 0.38 ML, in good agreement with recent density functional theory calculations.

Sea level: measuring the bounding surfaces of the ocean

Science.gov (United States)

Tamisiea, Mark E.; Hughes, Chris W.; Williams, Simon D. P.; Bingley, Richard M.

2014-01-01

The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. PMID:25157196

Origin of metallic surface core-level shifts

DEFF Research Database (Denmark)

Aldén, Magnus; Skriver, Hans Lomholt; Abrikosov, I. A.

1995-01-01

The unique property of the open 4f energy shell in the lanthanide metals is used to show that the initial-state energy shift gives an insufficient description of surface core-level shifts. Instead a treatment, which fully includes the final-state screening, account for the experimentally observed...

Five-year results after valve replacement with the Björk-Shiley 70 degrees convexo-concave prosthesis.

Science.gov (United States)

Koldsland, S; Svennevig, J L; Abdelnoor, M; Aas, H; Semb, G

1992-01-01

In the 18 months up to July 1983, 120 Björk-Shiley convexo-concave prostheses with 70 degrees opening angle were implanted in 47 women and 61 men aged 19-78 (mean 58.6) years. The prosthetic valves were aortic in 65 cases, mitral in 23 and both aortic and mitral in 20 cases. Emergency operation was required in ten cases, and concomitant surgery was performed in 43 (39.8%). The early mortality was 5.5%. A follow-up study, comprising 498 patient years, revealed 73.1% 5-year survival. There were three mechanical failures of prosthesis, in one of which re-replacement was successful. Elective prosthesis replacement was performed in four other cases judged to be at high risk of strut fracture.

Sea level: measuring the bounding surfaces of the ocean.

Science.gov (United States)

Tamisiea, Mark E; Hughes, Chris W; Williams, Simon D P; Bingley, Richard M

2014-09-28

The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Mikro-Elektro-Mechanisches System und Verfahren zum Herstellen desselben

OpenAIRE

Lisec, Thomas; Stoppel, Fabian

2015-01-01

A microelectromechanical system comprises a deflectable actuator plate and a stop surface. An integral piezoelectric functional layer of the deflectable actuator plate is formed over an area (APS) of the actuator plate. The deflectable actuator plate is designed to implement a concave curvature in at least one driven or non-driven state, wherein the stop surface is arranged in a manner facing a concave side of the deflectable actuator plate defined by the concave curvature. The deflectable ac...

Loading Mode and Environment Effects on Surface Profile Characteristics of Martensite Plates in Cu-Based SMAs

Science.gov (United States)

Suru, Marius-Gabriel; Paraschiv, Adrian-Liviu; Lohan, Nicoleta Monica; Pricop, Bogdan; Ozkal, Burak; Bujoreanu, Leandru-Gheorghe

2014-07-01

The present work reports the influence of the loading mode provided during training under constant stress, in bending, applied to lamellar specimens of Cu-Zn-Al shape memory alloys (SMAs). During training, the specimens were bent by a load fastened at their free end, while being martensitic at room temperature and they lifted the load by one-way effect (1WE), during heating up to austenitic field. On cooling to martensite field, the lower concave surface of bent specimens was compressed, and during heating it was elongated, being subjected to a series of tension-compression cycles, during heating-cooling, respectively. Conversely, the upper convex surface of bent specimens was elongated during cooling and compressed during heating, being subjected to compression-tension cycles. Furthermore, 2WE-trained actuators were tested by means of a hydraulic installation where, this time heating-cooling cycles were performed in oil conditions. Considering that the lower concave surface of the specimens was kept in compressed state, while the upper convex surface was kept in elongated state, the study reveals the influence of the two loading modes and environments on the width of martensite plates of the specimens trained under various numbers of cycles. In this purpose, Cu-Zn-Al specimens, trained under 100-300-500 cycles, were prepared and analyzed by atomic force microscopy (AFM) as well as optical and scanning electron microscopy (OM and SEM, respectively). The analysis also included AFM micrographs corroborated with statistical evaluations in order to reveal the effects of loading mode (tension or compression) in different environmental conditions of the specimens, on the surface profile characteristics of martensite plates, revealed by electropolishing.

Manufacturing microsystems-on-a-chip with 5-level surface micromachining technology

Energy Technology Data Exchange (ETDEWEB)

Sniegowski, J.; Rodgers, M.S.

1998-05-01

An agile microsystem manufacturing technology has been developed that provides unprecedented 5 levels of independent polysilicon surface-micromachine films for the designer. Typical surface-micromachining processes offer a maximum of 3 levels, making this the most complex surface-micromachining process technology developed to date. Leveraged from the extensive infrastructure present in the microelectronics industry, the manufacturing method of polysilicon surface-micromachining offers similar advantages of high-volume, high-reliability, and batch-fabrication to microelectromechanical systems (MEMS) as has been accomplished with integrated circuits (ICs). These systems, comprised of microscopic-sized mechanical elements, are laying the foundation for a rapidly expanding, multi-billion dollar industry 2 which impacts the automotive, consumer product, and medical industries to name only a few.

Practical Calculation of Thermal Deformation and Manufacture Error uin Surface Grinding

Institute of Scientific and Technical Information of China (English)

周里群; 李玉平

2002-01-01

The paper submits a method to calculate thermal deformation and manufacture error in surface grinding.The author established a simplified temperature field model.and derived the thermal deformaiton of the ground workpiece,It is found that there exists not only a upwarp thermal deformation,but also a parallel expansion thermal deformation.A upwarp thermal deformation causes a concave shape error on the profile of the workpiece,and a parallel expansion thermal deformation causes a dimension error in height.The calculations of examples are given and compared with presented experiment data.

Optimized surface-slab excited-state muffin-tin potential and surface core level shifts

International Nuclear Information System (INIS)

Rundgren, J.

2003-01-01

An optimized muffin-tin (MT) potential for surface slabs with preassigned surface core-level shifts (SCLS's) is presented. By using the MT radii as adjustable parameters the model is able to conserve the definition of the SCLS with respect to the bulk and concurrently to generate a potential that is continuous at the MT radii. The model is conceived for elastic electron scattering in a surface slab with exchange-correlation interaction described by the local density approximation. The model employs two data bases for the self-energy of the signal electron (after Hedin and Lundqvist or Sernelius). The potential model is discussed in detail with two surface structures Be(101-bar0), for which SCLS's are available, and Cu(111)p(2x2)Cs, in which the close-packed radii of the atoms are extremely different. It is considered plausible that tensor LEED based on an optimized MT potential can be used for determining SCLS's

On conservation of renewable resources with stock-dependent return and non-concave production

International Nuclear Information System (INIS)

Olson, Lars J.; Roy, Santanu

1994-05-01

An analysis is presented of the intertemporal choice foundations underlying the conservation or extinction of renewable resources when the resource production function is non-concave and the immediate return function depends on both current consumption and the size of the resource stock. This case may exhibit nonlinear dynamics and extinction is possible from high stocks even if conservation occurs from lower stocks. The paper focusses on the influence of preferences and the production function on the efficiency of: global conservation, the existence of a safe standard of conservation, or extinction. We show that conservation is efficient under weaker conditions than the 'δ-productivity' requirements derived in models where return function is not stock-dependent. The marginal rate of substitution between investment and the stock plays an important role in addition to the discount factor and the marginal productivity of the resource. Extinction need not be optimal even if the intrinsic growth rate of the resource is less than the external rate of return. Our analysis demonstrates the potential role of taxes, subsidies, demand forces, and harvest costs in determining the efficiency of conservation or extinction. 3 figs., 1 appendix, 24 refs

On conservation of renewable resources with stock-dependent return and non-concave production

Energy Technology Data Exchange (ETDEWEB)

Olson, Lars J. [Department of Agricultural and Resource Economics, University of Maryland, College Park, MD (United States); Roy, Santanu [Econometric Institute, Erasmus University, Rotterdam (Netherlands)

1994-05-01

An analysis is presented of the intertemporal choice foundations underlying the conservation or extinction of renewable resources when the resource production function is non-concave and the immediate return function depends on both current consumption and the size of the resource stock. This case may exhibit nonlinear dynamics and extinction is possible from high stocks even if conservation occurs from lower stocks. The paper focusses on the influence of preferences and the production function on the efficiency of: global conservation, the existence of a safe standard of conservation, or extinction. We show that conservation is efficient under weaker conditions than the `{delta}-productivity` requirements derived in models where return function is not stock-dependent. The marginal rate of substitution between investment and the stock plays an important role in addition to the discount factor and the marginal productivity of the resource. Extinction need not be optimal even if the intrinsic growth rate of the resource is less than the external rate of return. Our analysis demonstrates the potential role of taxes, subsidies, demand forces, and harvest costs in determining the efficiency of conservation or extinction. 3 figs., 1 appendix, 24 refs.

A Level Set Discontinuous Galerkin Method for Free Surface Flows

DEFF Research Database (Denmark)

Grooss, Jesper; Hesthaven, Jan

2006-01-01

We present a discontinuous Galerkin method on a fully unstructured grid for the modeling of unsteady incompressible fluid flows with free surfaces. The surface is modeled by embedding and represented by a levelset. We discuss the discretization of the flow equations and the level set equation...

Distinction of heterogeneity on Au nanostructured surface based on phase contrast imaging of atomic force microscopy

International Nuclear Information System (INIS)

Jung, Mi; Choi, Jeong-Woo

2010-01-01

The discrimination of the heterogeneity of different materials on nanostructured surfaces has attracted a great deal of interest in biotechnology as well as nanotechnology. Phase imaging through tapping mode of atomic force microscopy (TMAFM) can be used to distinguish the heterogeneity on a nanostructured surface. Nanostructures were fabricated using anodic aluminum oxide (AAO). An 11-mercaptoundecanoic acid (11-MUA) layer adsorbed onto the Au nanodots through self-assembly to improve the bio-compatibility. The Au nanostructures that were modified with 11-MUA and the concave surfaces were investigated using the TMAFM phase images to compare the heterogeneous and homogeneous nanostructured surfaces. Although the topography and phase images were taken simultaneously, the images were different. Therefore, the contrast in the TMAFM phase images revealed the different compositional materials on the heterogeneous nanostructure surface.

Honeycomb surface-plasma negative-ion source

International Nuclear Information System (INIS)

Bel'chenko, Yu.I.

1983-01-01

A honeycomb surface-plasma source (SPS) of negative hydrogen ions the cathode of which consists of a great number of cells with spherical-concave surfaces, is described. Negative ions, knocked off the cathode by cesium-hydrogen discharge fast particles are accelerated in the near-cathode potential drop layer and focused geometrically on small emission apertures in the anode. Due to this, the gas and energy efficiency of the source is increased and the power density on the cathode is decreased. The H - yield is proportional to the number of celts. A pulse beam of negative ions with current up to 4 A is obtained and accelerated to 25 kV from the cathode effective area of 10.6 cm 2 through emission ports of 0.5 cm 2 total area. The honeycomb SPSs with a greater number of cells are promising as regards obtaining negative ion-beams with the current of scores of amperes

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

Science.gov (United States)

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

Three-Dimensional Steady Supersonic Euler Flow Past a Concave Cornered Wedge with Lower Pressure at the Downstream

Science.gov (United States)

Qu, Aifang; Xiang, Wei

2018-05-01

In this paper, we study the stability of the three-dimensional jet created by a supersonic flow past a concave cornered wedge with the lower pressure at the downstream. The gas beyond the jet boundary is assumed to be static. It can be formulated as a nonlinear hyperbolic free boundary problem in a cornered domain with two characteristic free boundaries of different types: one is the rarefaction wave, while the other one is the contact discontinuity, which can be either a vortex sheet or an entropy wave. A more delicate argument is developed to establish the existence and stability of the square jet structure under the perturbation of the supersonic incoming flow and the pressure at the downstream. The methods and techniques developed here are also helpful for other problems involving similar difficulties.

Trace-level mercury removal from surface water

International Nuclear Information System (INIS)

Klasson, K.T.; Bostick, D.T.

1998-01-01

Many sorbents have been developed for the removal of mercury and heavy metals from waters; however, most of the data published thus far do not address the removal of mercury to the target levels represented in this project. The application to which these sorbents are targeted for use is the removal of mercury from microgram-per-liter levels to low nanogram-per-liter levels. Sorbents with thiouronium, thiol, amine, sulfur, and proprietary functional groups were selected for these studies. Mercury was successfully removed from surface water via adsorption onto Ionac SR-4 and Mersorb resins to levels below the target goal of 12 ng/L in batch studies. A thiol-based resin performed the best, indicating that over 200,000 volumes of water could be treated with one volume of resin. The cost of the resin is approximately $0.24 per 1,000 gal of water

Multiple patterns of diblock copolymer confined in irregular geometries with soft surface

Science.gov (United States)

Li, Ying; Sun, Min-Na; Zhang, Jin-Jun; Pan, Jun-Xing; Guo, Yu-Qi; Wang, Bao-Feng; Wu, Hai-Shun

2015-12-01

The different confinement shapes can induce the formation of various interesting and novel morphologies, which might inspire potential applications of materials. In this paper, we study the directed self-assembly of diblock copolymer confined in irregular geometries with a soft surface by using self-consistent field theory. Two types of confinement geometries are considered, namely, one is the concave pore with one groove and the other is the concave pore with two grooves. We obtain more novel and different structures which could not be produced in other two-dimensional (2D) confinements. Comparing these new structures with those obtained in regular square confinement, we find that the range of ordered lamellae is enlarged and the range of disordered structure is narrowed down under the concave pore confinement. We also compare the different structures obtained under the two types of confinement geometries, the results show that the effect of confinement would increase, which might induce the diblock copolymer to form novel structures. We construct the phase diagram as a function of the fraction of B block and the ratio of h/L of the groove. The simulation reveals that the wetting effect of brushes and the shape of confinement geometries play important roles in determining the morphologies of the system. Our results improve the applications in the directed self-assembly of diblock copolymer for fabricating the irregular structures. Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20121404110004), the Research Foundation for Excellent Talents of Shanxi Provincial Department of Human Resources and Social Security, China, and the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province, China.

Surface waves on currents with arbitrary vertical shear

Science.gov (United States)

Smeltzer, Benjamin K.; Ellingsen, Simen Å.

2017-04-01

We study dispersion properties of linear surface gravity waves propagating in an arbitrary direction atop a current profile of depth-varying magnitude using a piecewise linear approximation and develop a robust numerical framework for practical calculation. The method has been much used in the past for the case of waves propagating along the same axis as the background current, and we herein extend and apply it to problems with an arbitrary angle between the wave propagation and current directions. Being valid for all wavelengths without loss of accuracy, the scheme is particularly well suited to solve problems involving a broad range of wave vectors, such as ship waves and Cauchy-Poisson initial value problems. We examine the group and phase velocities over different wavelength regimes and current profiles, highlighting characteristics due to the depth-variable vorticity. We show an example application to ship waves on an arbitrary current profile and demonstrate qualitative differences in the wake patterns between concave down and concave up profiles when compared to a constant shear profile with equal depth-averaged vorticity. We also discuss the nature of additional solutions to the dispersion relation when using the piecewise-linear model. These are vorticity waves, drifting vortical structures which are artifacts of the piecewise model. They are absent for a smooth profile and are spurious in the present context.

Solvent-induced synthesis of nitrogen-doped hollow carbon spheres with tunable surface morphology for supercapacitors

Science.gov (United States)

Liu, Feng; Yuan, Ren-Lu; Zhang, Ning; Ke, Chang-Ce; Ma, Shao-Xia; Zhang, Ru-Liang; Liu, Lei

2018-04-01

Nitrogen doped hollow carbon spheres (NHCSs) with tunable surface morphology have been prepared through one-pot carbonization method by using melamine-formaldehyde spheres as template and resorcinol-based resin as carbon precursor in ethanol-water solution. Well-dispersed NHCSs with particle size of 800 nm were obtained and the surface of NHCSs turn from smooth to tough, wrinkled, and finally concave by increasing the ethanol concentration. The fabricated NHCSs possessed high nitrogen content (3.99-4.83%) and hierarchical micro-dual mesoporous structure with surface area range of 265-405 m2 g-1 and total pore volume of 0.18-0.29 cm3 g-1, which contributed to high specific capacitance, excellent rate capability and long cycle life.

Two Surface-Tension Formulations For The Level Set Interface-Tracking Method

International Nuclear Information System (INIS)

Shepel, S.V.; Smith, B.L.

2005-01-01

The paper describes a comparative study of two surface-tension models for the Level Set interface tracking method. In both models, the surface tension is represented as a body force, concentrated near the interface, but the technical implementation of the two options is different. The first is based on a traditional Level Set approach, in which the surface tension is distributed over a narrow band around the interface using a smoothed Delta function. In the second model, which is based on the integral form of the fluid-flow equations, the force is imposed only in those computational cells through which the interface passes. Both models have been incorporated into the Finite-Element/Finite-Volume Level Set method, previously implemented into the commercial Computational Fluid Dynamics (CFD) code CFX-4. A critical evaluation of the two models, undertaken in the context of four standard Level Set benchmark problems, shows that the first model, based on the smoothed Delta function approach, is the more general, and more robust, of the two. (author)

Definition and measurement of statistical gloss parameters from curved objects

Energy Technology Data Exchange (ETDEWEB)

Kuivalainen, Kalle; Oksman, Antti; Peiponen, Kai-Erik

2010-09-20

Gloss standards are commonly defined for gloss measurement from flat surfaces, and, accordingly, glossmeters are typically developed for flat objects. However, gloss inspection of convex, concave, and small products is also important. In this paper, we define statistical gloss parameters for curved objects and measure gloss data on convex and concave surfaces using two different diffractive-optical-element-based glossmeters. Examples of measurements with the two diffractive-optical-element-based glossmeters are given for convex and concave aluminum pipe samples with and without paint. The defined gloss parameters for curved objects are useful in the characterization of the surface quality of metal pipes and other objects.

Definition and measurement of statistical gloss parameters from curved objects

International Nuclear Information System (INIS)

Kuivalainen, Kalle; Oksman, Antti; Peiponen, Kai-Erik

2010-01-01

Gloss standards are commonly defined for gloss measurement from flat surfaces, and, accordingly, glossmeters are typically developed for flat objects. However, gloss inspection of convex, concave, and small products is also important. In this paper, we define statistical gloss parameters for curved objects and measure gloss data on convex and concave surfaces using two different diffractive-optical-element-based glossmeters. Examples of measurements with the two diffractive-optical-element-based glossmeters are given for convex and concave aluminum pipe samples with and without paint. The defined gloss parameters for curved objects are useful in the characterization of the surface quality of metal pipes and other objects.

Improved acoustic levitation apparatus

Science.gov (United States)

Berge, L. H.; Johnson, J. L.; Oran, W. A.; Reiss, D. A.

1980-01-01

Concave driver and reflector enhance and shape levitation forces in acoustic resonance system. Single-mode standing-wave pattern is focused by ring element situated between driver and reflector. Concave surfaces increase levitating forces up to factor of 6 as opposed to conventional flat surfaces, making it possible to suspend heavier objects.

[Strut fracture of a convex-concave 60 degree Björk-Shiley mitral valve prosthesis 5 years after implantation--metallurgic analysis of the prosthesis strut].

Science.gov (United States)

Lemke, B; Rathmann, J; Wiebe, V; Witzel, U

1991-08-01

Acute mechanical failure of prosthetic heart valves is rare, but associated with high mortality when occurring. For convexo-concave Björk-Shiley prostheses only fractures of the outlet strut are reported. We present a case of lethal mechanical complication 5 years after implantation. By additional metallurgic analysis we were able to identify a sequential course of the outlet strut fracture. This could lead to new approaches for early detection of this complication.

Outlet strut fracture of Björk-Shiley convexo-concave valves: can valve-manufacturing characteristics explain the risk?

Science.gov (United States)

Omar, R Z; Morton, L S; Beirne, M; Blot, W J; Lawford, P V; Hose, R; Taylor, K M

2001-06-01

Björk-Shiley 60 degrees convexo-concave prosthetic heart valves (Shiley, Inc, Irvine, Calif, a subsidiary of Pfizer, Inc) continue to be a concern for approximately 35,000 nonexplanted patients worldwide, with approximately 600 events reported to the manufacturer to date. Fractures of the outlet struts of the valves began to appear in the early 1980s and have continued to the present, but their causes are only partially understood. A matched case-control study was conducted evaluating manufacturing records for 52 valves with outlet strut fractures and 248 control subjects matched for age at implantation, valve size, and valve position. In addition to the risk factors recognized as determinants of outlet strut fracture, the United Kingdom case-control study has observed 7- to 9-fold increased risk with performance of multiple hook deflection tests. This test was performed more than once, usually after rework on the valve. Six valves in this study underwent multiple hook deflection tests, of which 4 experienced an outlet strut fracture. Cracks and further rework were noted for these valves. Significant associations were also observed between outlet strut fracture and disc-to-strut gap measurements taken before the attachment of the sewing ring. It is our view that a combination of factors related to valve design, manufacturing process, and patient characteristics are responsible for outlet strut fractures of Björk-Shiley convexo-concave valves. Multiple hook deflection tests have emerged as a potential new risk factor for outlet strut fracture in both The Netherlands and the United Kingdom. This factor appears to be correlated with the presence of other abnormalities. A further study is needed to investigate the factors correlated with multiple hook deflection tests. On confirmation of risk, the presence of multiple hook deflection tests may be added to equations, quantifying the risk of outlet strut fracture for comparison against risk of mortality and serious

Structural dependence of the 5d-metal surface energies as deduced from surface core-level shift measurements

International Nuclear Information System (INIS)

Mrartensson, N.; Saalfeld, H.B.; Kuhlenbeck, H.; Neumann, M.

1989-01-01

Surface core-level shift measurements performed at the BESSY storage ring yield -0.41(2) eV for Os(0001) and 0.00(10) eV for Re(0001). An analysis of the surface shifts in the 5d transition series shows that the surface energy as a function of Z has a maximum at lower Z for the bcc phase than for the fcc-hcp phases, at W and between Re and Os, respectively

Mapping Hydrophobicity on the Protein Molecular Surface at Atom-Level Resolution

Science.gov (United States)

Nicolau Jr., Dan V.; Paszek, Ewa; Fulga, Florin; Nicolau, Dan V.

2014-01-01

A precise representation of the spatial distribution of hydrophobicity, hydrophilicity and charges on the molecular surface of proteins is critical for the understanding of the interaction with small molecules and larger systems. The representation of hydrophobicity is rarely done at atom-level, as this property is generally assigned to residues. A new methodology for the derivation of atomic hydrophobicity from any amino acid-based hydrophobicity scale was used to derive 8 sets of atomic hydrophobicities, one of which was used to generate the molecular surfaces for 35 proteins with convex structures, 5 of which, i.e., lysozyme, ribonuclease, hemoglobin, albumin and IgG, have been analyzed in more detail. Sets of the molecular surfaces of the model proteins have been constructed using spherical probes with increasingly large radii, from 1.4 to 20 Å, followed by the quantification of (i) the surface hydrophobicity; (ii) their respective molecular surface areas, i.e., total, hydrophilic and hydrophobic area; and (iii) their relative densities, i.e., divided by the total molecular area; or specific densities, i.e., divided by property-specific area. Compared with the amino acid-based formalism, the atom-level description reveals molecular surfaces which (i) present an approximately two times more hydrophilic areas; with (ii) less extended, but between 2 to 5 times more intense hydrophilic patches; and (iii) 3 to 20 times more extended hydrophobic areas. The hydrophobic areas are also approximately 2 times more hydrophobicity-intense. This, more pronounced “leopard skin”-like, design of the protein molecular surface has been confirmed by comparing the results for a restricted set of homologous proteins, i.e., hemoglobins diverging by only one residue (Trp37). These results suggest that the representation of hydrophobicity on the protein molecular surfaces at atom-level resolution, coupled with the probing of the molecular surface at different geometric resolutions

The hydrogen abstraction reaction O(3P) + CH4: A new analytical potential energy surface based on fit to ab initio calculations

International Nuclear Information System (INIS)

González-Lavado, Eloisa; Corchado, Jose C.; Espinosa-Garcia, Joaquin

2014-01-01

Based exclusively on high-level ab initio calculations, a new full-dimensional analytical potential energy surface (PES-2014) for the gas-phase reaction of hydrogen abstraction from methane by an oxygen atom is developed. The ab initio information employed in the fit includes properties (equilibrium geometries, relative energies, and vibrational frequencies) of the reactants, products, saddle point, points on the reaction path, and points on the reaction swath, taking especial caution respecting the location and characterization of the intermediate complexes in the entrance and exit channels. By comparing with the reference results we show that the resulting PES-2014 reproduces reasonably well the whole set of ab initio data used in the fitting, obtained at the CCSD(T) = FULL/aug-cc-pVQZ//CCSD(T) = FC/cc-pVTZ single point level, which represents a severe test of the new surface. As a first application, on this analytical surface we perform an extensive dynamics study using quasi-classical trajectory calculations, comparing the results with recent experimental and theoretical data. The excitation function increases with energy (concave-up) reproducing experimental and theoretical information, although our values are somewhat larger. The OH rotovibrational distribution is cold in agreement with experiment. Finally, our results reproduce experimental backward scattering distribution, associated to a rebound mechanism. These results lend confidence to the accuracy of the new surface, which substantially improves the results obtained with our previous surface (PES-2000) for the same system

Self-consistent Green’s-function technique for bulk and surface impurity calculations: Surface core-level shifts by complete screening

DEFF Research Database (Denmark)

Aldén, M.; Abrikosov, I. A.; Johansson, B.

1994-01-01

of the frozen-core and atomic-sphere approximation but, in addition, includes the dipole contribution to the intersphere potential. Within the concept of complete screening, we identify the surface core-level binding-energy shift with the surface segregation energy of a core-ionized atom and use the Green......'s-function impurity technique in a comprehensive study of the surface core-level shifts (SCLS) of the 4d and 5d transition metals. In those cases, where observed data refer to single crystals, we obtain good agreement with experiment, whereas the calculations typically underestimate the measured shift obtained from...

A high resolution photoemission study of surface core-level shifts in clean and oxygen-covered Ir(2 1 0) surfaces

Energy Technology Data Exchange (ETDEWEB)

Gladys, M.J.; Ermanoski, I.; Jackson, G.; Quinton, J.S.; Rowe, J.E.; Madey, T.E. E-mail: madey@physics.rutgers.edu

2004-04-01

High resolution soft X-ray photoemission electron spectroscopy (SXPS), using synchrotron radiation, is employed to investigate 4f core-level features of four differently-prepared Ir(2 1 0) surfaces: clean planar, oxygen-covered planar, oxygen-induced faceted, and clean faceted surfaces. Surface and bulk peak identifications are supported by measurements at different photon energies (thus probing different electron escape depths) and variable emission angles. Iridium 4f{sub 7/2} photoemission spectra are fitted with Doniach-Sunjic lineshapes. The surface components are identified with core levels positioned at lower binding energies than the bulk components, in contrast to previous reports of binding energy inversion on Ir(1 0 0) (1x1) and (5x1) surfaces. For clean planar Ir(2 1 0) three surface Ir 4f{sub 7/2} features are observed with core-level shifts of -765, -529, and -281 meV, with respect to the bulk; these are associated with the first, second and third layers of atoms, respectively, for atomically rough Ir(2 1 0). Adsorption of oxygen onto the planar Ir(2 1 0) surface is found to cause a suppression and shift of the surface features to higher binding energies. Annealing at T{>=}600 K in oxygen produces a faceted surface as verified by low energy electron diffraction (LEED). A comparison of planar and faceted oxygen-covered surfaces reveals minor differences in the normal emission SXPS spectra, while grazing emission spectra exhibit differences. The SXPS spectrum of the clean, faceted Ir(2 1 0) exhibits small differences in comparison to the clean planar case, with surface features having binding energy shifts of -710, -450, and -230 meV.

Influence of Layup Sequence on the Surface Accuracy of Carbon Fiber Composite Space Mirrors

Science.gov (United States)

Yang, Zhiyong; Liu, Qingnian; Zhang, Boming; Xu, Liang; Tang, Zhanwen; Xie, Yongjie

2018-04-01

Layup sequence is directly related to stiffness and deformation resistance of the composite space mirror, and error caused by layup sequence can affect the surface precision of composite mirrors evidently. Variation of layup sequence with the same total thickness of composite space mirror changes surface form of the composite mirror, which is the focus of our study. In our research, the influence of varied quasi-isotropic stacking sequences and random angular deviation on the surface accuracy of composite space mirrors was investigated through finite element analyses (FEA). We established a simulation model for the studied concave mirror with 500 mm diameter, essential factors of layup sequences and random angular deviations on different plies were discussed. Five guiding findings were described in this study. Increasing total plies, optimizing stacking sequence and keeping consistency of ply alignment in ply placement are effective to improve surface accuracy of composite mirror.

Detection for flatness of large surface based on structured light

Science.gov (United States)

He, Wenyan; Cao, Xuedong; Long, Kuang; Peng, Zhang

2016-09-01

In order to get flatness of a large plane, this paper set up a measurement system, composed by Line Structured Light, imaging system, CCD, etc. Line Structured Light transmits parallel fringes at a proper angle onto the plane which is measured; the imaging system and CCD locate above the plane to catch the fringes. When the plane is perfect, CCD will catch straight fringes; however, the real plane is not perfect; according to the theory of projection, the fringes caught by CCD will be distorted by convex and concave. Extract the center of line fringes to obtain the distortion of the fringe, according to the functional relationship between the distortion of fringes and the height which is measured, then we will get flatness of the entire surface. Data from experiment approached the analysis of theory. In the simulation, the vertical resolution is 0.0075 mm per pixel when measuring a plane of 400mm×400mm, choosing the size of CCD 4096×4096, at the angle 85°. Helped by sub-pixel, the precision will get the level of submicron. There are two obvious advantages: method of surface sampling can increase the efficiency for auto-repairing of machines; considering the center of fringe is required mainly in this system, as a consequence, there is no serious demand for back light.

Assessment of surface contamination level in an operating uranium ore processing facility of Jaduguda, India

International Nuclear Information System (INIS)

Meena, J.S.; Patnaik, R.L.; Jha, V.N.; Sahoo, S.K.; Ravi, P.M.; Tripathi, R.M.

2014-01-01

Radiological concern of the occupational workers and the area is given priority over other safety issue in confirmation with the stipulated guideline of national regulatory agency (AERB/FEFCF/SG-2, 2007). The key concern from the radiological hazard evaluation point of view is air activity, external gamma level and surface contamination. Present investigations was carried out to ascertain the surface contamination level of uranium ore processing facility at Jaduguda, Jharkhand. For a low grade uranium ore processing industry surface contamination is a major concern in product precipitation and recovery section. In view of this, the ore processing plant can broadly be classified into three areas i.e. ion exchange area, precipitation and product recovery section and other areas. The monitoring results incorporate the level of surface contamination of the plant during the last five years. The geometric mean activity of surface contamination level was 31.1, 34.5 and 9.8 Bq dm -2 in ion exchange, product precipitation and recovery and other areas with GSD of 2, 2.5 and 1.9. In most of the cases the surface contamination level was well within the recommended limit of 100 Bq dm -2 for M class uranium compound. Occasional cases of surface contamination levels exceeding the recommended limit were addressed and areas were decontaminated. Based on the study, modification in the design feature of the surface of the finished product section was also suggested so that the decontamination procedure can be more effectively implemented

Behavior of Rydberg atoms at surfaces: energy level shifts and ionization

Energy Technology Data Exchange (ETDEWEB)

Dunning, F.B. E-mail: fbd@rice.edu; Dunham, H.R.; Oubre, C.; Nordlander, P

2003-04-01

The ionization of xenon atoms excited to the extreme red and blue states in high-lying Xe(n) Stark manifolds at a metal surface is investigated. The data show that, despite their very different initial spatial characteristics, the extreme members of a given Stark manifold ionize at similar atom/surface separations. This is explained, with the aid of complex scaling calculations, in terms of the strong perturbations in the energies and structure of the atomic states induced by the presence of the surface which lead to avoided crossings between neighboring levels as the surface is approached.

Behavior of Rydberg atoms at surfaces: energy level shifts and ionization

CERN Document Server

Dunning, F B; Oubre, C D; Nordlander, P

2003-01-01

The ionization of xenon atoms excited to the extreme red and blue states in high-lying Xe(n) Stark manifolds at a metal surface is investigated. The data show that, despite their very different initial spatial characteristics, the extreme members of a given Stark manifold ionize at similar atom/surface separations. This is explained, with the aid of complex scaling calculations, in terms of the strong perturbations in the energies and structure of the atomic states induced by the presence of the surface which lead to avoided crossings between neighboring levels as the surface is approached.

Improvements to the swath-level near-surface atmospheric state parameter retrievals within the NRL Ocean Surface Flux System (NFLUX)

Science.gov (United States)

May, J. C.; Rowley, C. D.; Meyer, H.

2017-12-01

The Naval Research Laboratory (NRL) Ocean Surface Flux System (NFLUX) is an end-to-end data processing and assimilation system used to provide near-real-time satellite-based surface heat flux fields over the global ocean. The first component of NFLUX produces near-real-time swath-level estimates of surface state parameters and downwelling radiative fluxes. The focus here will be on the satellite swath-level state parameter retrievals, namely surface air temperature, surface specific humidity, and surface scalar wind speed over the ocean. Swath-level state parameter retrievals are produced from satellite sensor data records (SDRs) from four passive microwave sensors onboard 10 platforms: the Special Sensor Microwave Imager/Sounder (SSMIS) sensor onboard the DMSP F16, F17, and F18 platforms; the Advanced Microwave Sounding Unit-A (AMSU-A) sensor onboard the NOAA-15, NOAA-18, NOAA-19, Metop-A, and Metop-B platforms; the Advanced Technology Microwave Sounder (ATMS) sensor onboard the S-NPP platform; and the Advanced Microwave Scannin Radiometer 2 (AMSR2) sensor onboard the GCOM-W1 platform. The satellite SDRs are translated into state parameter estimates using multiple polynomial regression algorithms. The coefficients to the algorithms are obtained using a bootstrapping technique with all available brightness temperature channels for a given sensor, in addition to a SST field. For each retrieved parameter for each sensor-platform combination, unique algorithms are developed for ascending and descending orbits, as well as clear vs cloudy conditions. Each of the sensors produces surface air temperature and surface specific humidity retrievals. The SSMIS and AMSR2 sensors also produce surface scalar wind speed retrievals. Improvement is seen in the SSMIS retrievals when separate algorithms are used for the even and odd scans, with the odd scans performing better than the even scans. Currently, NFLUX treats all SSMIS scans as even scans. Additional improvement in all of

Scaling of heat transfer augmentation due to mechanical distortions in hypervelocity boundary layers

Science.gov (United States)

Flaherty, W.; Austin, J. M.

2013-10-01

We examine the response of hypervelocity boundary layers to global mechanical distortions due to concave surface curvature. Surface heat transfer and visual boundary layer thickness data are obtained for a suite of models with different concave surface geometries. Results are compared to predictions using existing approximate methods. Near the leading edge, good agreement is observed, but at larger pressure gradients, predictions diverge significantly from the experimental data. Up to a factor of five underprediction is reported in regions with greatest distortion. Curve fits to the experimental data are compared with surface equations. We demonstrate that reasonable estimates of the laminar heat flux augmentation may be obtained as a function of the local turning angle for all model geometries, even at the conditions of greatest distortion. This scaling may be explained by the application of Lees similarity. As a means of introducing additional local distortions, vortex generators are used to impose streamwise structures into the boundary layer. The response of the large scale vortices to an adverse pressure gradient is investigated. Surface streak evolution is visualized over the different surface geometries using fast response pressure sensitive paint. For a flat plate baseline case, heat transfer augmentation at similar levels to turbulent flow is measured. For the concave geometries, increases in heat transfer by factors up to 2.6 are measured over the laminar values. The scaling of heat transfer with turning angle that is identified for the laminar boundary layer response is found to be robust even in the presence of the imposed vortex structures.

Myopic keratomileusis by excimer laser on a lathe.

Science.gov (United States)

Ganem, S; Aron-Rosa, D; Gross, M; Rosolen, S

1994-01-01

We designed an excimer laser keratomileusis delivery system to increase the regularity of the refractive cut surface and allow greater precision in the level and shape of the ablated zone. A parallel faced corneal disc was produced by microkeratectomy from six human eyes and surgical keratectomy in 12 beagle corneas. A 193-nanometer excimer laser that was used to project an oval beam onto the corneal disc was rotated on a flat surface to ensure overlapping of the ovally ablated areas between pulses. Electron microscopy of eye bank lenticules demonstrated a circular smooth regularly concave ablation zone. Histological examination of nine clear corneas confirmed thinning of the stroma without fibroblastic reaction and no epithelial hypertrophy. Mean preoperative corneal power of 43.15 +/- 2.18 decreased postoperatively to 33.61 +/- 2.34. The new technique of excimer laser keratomileusis has the advantage of a cut surface smoother and the clear zone is devoid of the stepwise concavity and irregularity seen in diaphragm based photoablation delivery systems.

Evaluation of the levels of phthalate ester plasticizers in surface ...

African Journals Online (AJOL)

Evaluation of the levels of phthalate ester plasticizers in surface water of Ethiope ... Gas chromatography (GC) coupled with mass spectrometer (MS) was used to ... with their common use in plastic materials and other industrial chemicals.

Severity of MIH findings at tooth surface level among German school children.

Science.gov (United States)

Petrou, M A; Giraki, M; Bissar, A-R; Wempe, C; Schäfer, M; Schiffner, U; Beikler, T; Schulte, A G; Splieth, C H

2015-06-01

This study was to investigate the distribution and clinical characteristics of teeth diagnosed with MIH at surface and defect type level in a cohort of German children. The study cohort included 242 children diagnosed with MIH which had been recorded during the compulsory dental school examinations of 20 German primary schools. The subjects had been enrolled by cluster sampling. All children attended the second to fourth grade (age 7-10 years, mean 8.1 ± 0.8). The children were examined by five calibrated examiners (kappa = 0.9) after tooth brushing. The recording comprised teeth, surfaces, type and severity of MIH defects and was conducted using a portable light, mirrors and cotton rolls. MIH was registered according to the EAPD criteria. Defects MIH defects at various surfaces of the same tooth were common. The number of affected tooth surfaces was positively correlated with the severity of MIH at child (p MIH teeth. The knowledge of the intra-oral distribution and severity of MIH findings at the enamel surface level is important for assessing the treatment needs.

Gait Characteristics Associated with Trip-Induced Falls on Level and Sloped Irregular Surfaces

Directory of Open Access Journals (Sweden)

Andrew Merryweather

2011-11-01

Full Text Available Same level falls continue to contribute to an alarming number of slip/trip/fall injuries in the mining workforce. The objective of this study was to investigate how walking on different surface types and transverse slopes influences gait parameters that may be associated with a trip event. Gait analysis was performed for ten subjects on two orientations (level and sloped on smooth, hard surface (control and irregular (gravel, larger rocks surfaces. Walking on irregular surfaces significantly increased toe clearance compared to walking on the smooth surface. There was a significant (p < 0.05 decrease in cadence (steps/min, stride length (m, and speed (m/s from control to gravel to larger rocks. Significant changes in external rotation and increased knee flexion while walking on irregular surfaces were observed. Toe and heel clearance requirements increased on irregular surfaces, which may provide an explanation for trip-induced falls; however, the gait alterations observed in the experienced workers used as subjects would likely improve stability and recovery from a trip.

Functional levels of floor surface roughness for the prevention of slips and falls: clean-and-dry and soapsuds-covered wet surfaces.

Science.gov (United States)

Kim, In-Ju; Hsiao, Hongwei; Simeonov, Peter

2013-01-01

Literature has shown a general trend that slip resistance performance improves with floor surface roughness. However, whether slip resistance properties are linearly correlated with surface topographies of the floors or what roughness levels are required for effective slip resistance performance still remain to be answered. This pilot study aimed to investigate slip resistance properties and identify functional levels of floor surface roughness for practical design applications in reducing the risk of slip and fall incidents. A theory model was proposed to characterize functional levels of surface roughness of floor surfaces by introducing a new concept of three distinctive zones. A series of dynamic friction tests were conducted using 3 shoes and 9 floor specimens under clean-and-dry as well as soapsuds-covered slippery wet environments. The results showed that all the tested floor-shoe combinations provided sufficient slip resistances performance under the clean-and-dry condition. A significant effect of floor type (surface roughness) on dynamic friction coefficient (DFC) was found in the soapsuds-covered wet condition. As compared to the surface roughness effects, the shoe-type effects were relatively small. Under the soapsuds-covered wet condition, floors with 50 μm in Ra roughness scale seemed to represent an upper bound in the functional range of floor surface roughness for slip resistance because further increase of surface roughness provided no additional benefit. A lower bound of the functional range for slip resistance under the soapsuds-covered wet condition was estimated from the requirement of DFC > 0.4 at Ra ≅ 17 μm. Findings from this study may have potential safety implications in the floor surface design for reducing slip and fall hazards. Published by Elsevier Ltd.

Retrievable surface storage: interim storage of solidified high-level waste

International Nuclear Information System (INIS)

LaRiviere, J.R.; Nelson, D.C.

1976-01-01

Studies have been conducted on retrievable-surface-storage concepts for the interim storage of solidified high-level wastes. These studies have been reviewed by the Panel on Engineered Storage, convened by the Committee on Radioactive Waste Management of the National Research Council-National Academy of Sciences. The Panel has concluded that ''retrievable surface storage is an acceptable interim stage in a comprehensive system for managing high-level radioactive wastes.'' The scaled storage cask concept, which was recommended by the Panel on Engineered Storage, consists of placing a canister of waste inside a carbon-steel cask, which in turn is placed inside a thick concrete cylinder. The waste is cooled by natural convection air flow through an annulus between the cask and the inner wall of the concrete cylinder. The complete assembly is placed above ground in an outdoor storage area

GHRSST Level 4 ODYSSEA Global Foundation Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

Immobilized enzymes: understanding enzyme - surface interactions at the molecular level.

Science.gov (United States)

Hoarau, Marie; Badieyan, Somayesadat; Marsh, E Neil G

2017-11-22

Enzymes immobilized on solid supports have important and industrial and medical applications. However, their uses are limited by the significant reductions in activity and stability that often accompany the immobilization process. Here we review recent advances in our understanding of the molecular level interactions between proteins and supporting surfaces that contribute to changes in stability and activity. This understanding has been facilitated by the application of various surface-sensitive spectroscopic techniques that allow the structure and orientation of enzymes at the solid/liquid interface to be probed, often with monolayer sensitivity. An appreciation of the molecular interactions between enzyme and surface support has allowed the surface chemistry and method of enzyme attachement to be fine-tuned such that activity and stability can be greatly enhanced. These advances suggest that a much wider variety of enzymes may eventually be amenable to immobilization as green catalysts.

Structures of pseudechetoxin and pseudecin, two snake-venom cysteine-rich secretory proteins that target cyclic nucleotide-gated ion channels: implications for movement of the C-terminal cysteine-rich domain

International Nuclear Information System (INIS)

Suzuki, Nobuhiro; Yamazaki, Yasuo; Brown, R. Lane; Fujimoto, Zui; Morita, Takashi; Mizuno, Hiroshi

2008-01-01

The structures of pseudechetoxin and pseudecin suggest that both proteins bind to cyclic nucleotide-gated ion channels in a manner in which the concave surface occludes the pore entrance. Cyclic nucleotide-gated (CNG) ion channels play pivotal roles in sensory transduction by retinal photoreceptors and olfactory neurons. The elapid snake toxins pseudechetoxin (PsTx) and pseudecin (Pdc) are the only known protein blockers of CNG channels. These toxins belong to a cysteine-rich secretory protein (CRISP) family containing an N-terminal pathogenesis-related proteins of group 1 (PR-1) domain and a C-terminal cysteine-rich domain (CRD). PsTx and Pdc are highly homologous proteins, but their blocking affinities on CNG channels are different: PsTx blocks both the olfactory and retinal channels with ∼15–30-fold higher affinity than Pdc. To gain further insights into their structure and function, the crystal structures of PsTx, Pdc and Zn 2+ -bound Pdc were determined. The structures revealed that most of the amino-acid-residue differences between PsTx and Pdc are located around the concave surface formed between the PR-1 domain and the CRD, suggesting that the concave surface is functionally important for CNG-channel binding and inhibition. A structural comparison in the presence and absence of Zn 2+ ion demonstrated that the concave surface can open and close owing to movement of the CRD upon Zn 2+ binding. The data suggest that PsTx and Pdc occlude the pore entrance and that the dynamic motion of the concave surface facilitates interaction with the CNG channels

Structures of pseudechetoxin and pseudecin, two snake-venom cysteine-rich secretory proteins that target cyclic nucleotide-gated ion channels: implications for movement of the C-terminal cysteine-rich domain

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Nobuhiro [Department of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan); Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); Yamazaki, Yasuo [Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588 (Japan); Brown, R. Lane [Neurological Science Institute, Oregon Health and Science University, Beaverton, Oregon 97006 (United States); Fujimoto, Zui [Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); Morita, Takashi, E-mail: tmorita@my-pharm.ac.jp [Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588 (Japan); Mizuno, Hiroshi, E-mail: tmorita@my-pharm.ac.jp [Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); VALWAY Technology Center, NEC Soft Ltd, Koto-ku, Tokyo 136-8627 (Japan); Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology, Central 6, Tsukuba, Ibaraki 305-8566 (Japan); Department of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan)

2008-10-01

The structures of pseudechetoxin and pseudecin suggest that both proteins bind to cyclic nucleotide-gated ion channels in a manner in which the concave surface occludes the pore entrance. Cyclic nucleotide-gated (CNG) ion channels play pivotal roles in sensory transduction by retinal photoreceptors and olfactory neurons. The elapid snake toxins pseudechetoxin (PsTx) and pseudecin (Pdc) are the only known protein blockers of CNG channels. These toxins belong to a cysteine-rich secretory protein (CRISP) family containing an N-terminal pathogenesis-related proteins of group 1 (PR-1) domain and a C-terminal cysteine-rich domain (CRD). PsTx and Pdc are highly homologous proteins, but their blocking affinities on CNG channels are different: PsTx blocks both the olfactory and retinal channels with ∼15–30-fold higher affinity than Pdc. To gain further insights into their structure and function, the crystal structures of PsTx, Pdc and Zn{sup 2+}-bound Pdc were determined. The structures revealed that most of the amino-acid-residue differences between PsTx and Pdc are located around the concave surface formed between the PR-1 domain and the CRD, suggesting that the concave surface is functionally important for CNG-channel binding and inhibition. A structural comparison in the presence and absence of Zn{sup 2+} ion demonstrated that the concave surface can open and close owing to movement of the CRD upon Zn{sup 2+} binding. The data suggest that PsTx and Pdc occlude the pore entrance and that the dynamic motion of the concave surface facilitates interaction with the CNG channels.

GHRSST Level 4 GAMSSA Global Foundation Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Australian Bureau...

GHRSST Level 4 OSPO Global Foundation Sea Surface Temperature Analysis (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Office of...

Evaluation of hydrogen and oxygen impurity levels on silicon surfaces

Energy Technology Data Exchange (ETDEWEB)

Kenny, M.J.; Wielunski, L.S.; Netterfield, R.P.; Martin, P.J.; Leistner, A. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics

1996-12-31

This paper reports on surface analytical techniques used to quantify surface concentrations of impurities such as oxygen and hydrogen. The following analytical techniques were used: Rutherford and Backscattering, elastic recoil detection, time-of-flight SIMS, spectroscopic ellipsometry, x-ray photoelectron spectroscopy. The results have shown a spread in thickness of oxide layer, ranging from unmeasurable to 1.6 nm. The data must be considered as preliminary at this stage, but give some insight into the suitability of the techniques and a general idea of the significance of impurities at the monolayer level. These measurements have been carried out on a small number of silicon surfaces both semiconductor grade <111> crystalline material and silicon which has been used in sphere fabrication. 5 refs., 1 fig.

Evaluation of hydrogen and oxygen impurity levels on silicon surfaces

Energy Technology Data Exchange (ETDEWEB)

Kenny, M J; Wielunski, L S; Netterfield, R P; Martin, P J; Leistner, A [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics

1997-12-31

This paper reports on surface analytical techniques used to quantify surface concentrations of impurities such as oxygen and hydrogen. The following analytical techniques were used: Rutherford and Backscattering, elastic recoil detection, time-of-flight SIMS, spectroscopic ellipsometry, x-ray photoelectron spectroscopy. The results have shown a spread in thickness of oxide layer, ranging from unmeasurable to 1.6 nm. The data must be considered as preliminary at this stage, but give some insight into the suitability of the techniques and a general idea of the significance of impurities at the monolayer level. These measurements have been carried out on a small number of silicon surfaces both semiconductor grade <111> crystalline material and silicon which has been used in sphere fabrication. 5 refs., 1 fig.

Routing the asteroid surface vehicle with detailed mechanics

Science.gov (United States)

Yu, Yang; Baoyin, He-Xi

2014-06-01

The motion of a surface vehicle on/above an irregular object is investigated for a potential interest in the insitu explorations to asteroids of the solar system. A global valid numeric method, including detailed gravity and geomorphology, is developed to mimic the behaviors of the test particles governed by the orbital equations and surface coupling effects. A general discussion on the surface mechanical environment of a specified asteroid, 1620 Geographos, is presented to make a global evaluation of the surface vehicle's working conditions. We show the connections between the natural trajectories near the ground and differential features of the asteroid surface, which describes both the good and bad of typical terrains from the viewpoint of vehicles' dynamic performances. Monte Carlo simulations are performed to take a further look at the trajectories of particles initializing near the surface. The simulations reveal consistent conclusions with the analysis, i.e., the open-field flat ground and slightly concave basins/valleys are the best choices for the vehicles' dynamical security. The dependence of decending trajectories on the releasing height is studied as an application; the results show that the pole direction (where the centrifugal force is zero) is the most stable direction in which the shift of a natural trajectory will be well limited after landing. We present this work as an example for pre-analysis that provides guidance to engineering design of the exploration site and routing the surface vehicles.

Monitoring sea level and sea surface temperature trends from ERS satellites

DEFF Research Database (Denmark)

Andersen, Ole Baltazar; Knudsen, Per; Beckley, B.

2002-01-01

Data from the two ESA satellites ERS-1 and ERS-2 are used in global and regional analysis of sea level and sea surface temperature trends over the last, 7.8 years. T he ERS satellites and in the future the ENVISAT satellite provide unique opportunity for monitoring both changes in sea level and sea...

Observations of the structure and evolution of surface and flight-level wind asymmetries in Hurricane Rita (2005)

Science.gov (United States)

Rogers, Robert; Uhlhorn, Eric

2008-11-01

Knowledge of the magnitude and distribution of surface winds, including the structure of azimuthal asymmetries in the wind field, are important factors for tropical cyclone forecasting. With its ability to remotely measure surface wind speeds, the stepped frequency microwave radiometer (SFMR) has assumed a prominent role for the operational tropical cyclone forecasting community. An example of this instrument's utility is presented here, where concurrent measurements of aircraft flight-level and SFMR surface winds are used to document the wind field evolution over three days in Hurricane Rita (2005). The amplitude and azimuthal location (phase) of the wavenumber-1 asymmetry in the storm-relative winds varied at both levels over time. The peak was found to the right of storm track at both levels on the first day. By the third day, the peak in flight-level storm-relative winds remained to the right of storm track, but it shifted to left of storm track at the surface, resulting in a 60-degree shift between the surface and flight-level and azimuthal variations in the ratio of surface to flight-level winds. The asymmetric differences between the surface and flight-level maximum wind radii also varied, indicating a vortex whose tilt was increasing.

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

Science.gov (United States)

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.

Serum levels of vitamin A, visual function and ocular surface after bariatric surgery

Directory of Open Access Journals (Sweden)

Luana Paula Nogueira de Araújo BRANDÃO

Full Text Available ABSTRACT BACKGROUND Bariatric surgery is the most effective treatment for severe obesity, but the surgery increases the risk of developing nutritional deficiencies, such as vitamin A deficiency. In human metabolism, vitamin A plays a role in vision. OBJECTIVE To evaluate serum vitamin A, visual function and ocular surface of patients undergoing bariatric surgery. METHODS A cross-sectional and analytical study was conduced with 28 patients undergoing bariatric surgery for at least 6 months. Ophthalmologic evaluation was done through color vision test, contrast sensitivity test, ocular surface tests and confocal microscopy, as well as vitamin A serum measurement. RESULTS Vertical sleeve gastrectomy was performed in seven (25.0% patients and Roux -en-Y gastric by-pass in 21 (75.0%. Mean serum vitamin A level was 1.7±0.5 µmoL/L. Most patients (60.7% had symptoms of dry eye. Five (17.9% patients had contrast sensitivity impairment and 18 (64.3% color vision changes. In the group of patients undergoing Roux -en-Y gastric by-pass , mean vitamin A levels were 1.8±0.6 µmoL/L, whereas they were 1.7±0.5 µmoL/L in patients submitted to the restrictive technique vertical sleeve gastrectomy . The analysis of the influence of serum levels of vitamin A in the visual function and ocular surface was performed by Pearson correlation test and there was no significant correlation between any of the variables and vitamin A. CONCLUSION There was no influence of the bariatric surgery technique used on serum vitamin A levels, on the visual function or on the ocular surface. Moreover, there was no correlation between serum levels of vitamin A and the visual function or the ocular surface changes.

Deep layer-resolved core-level shifts in the beryllium surface

DEFF Research Database (Denmark)

Aldén, Magnus; Skriver, Hans Lomholt; Johansson, Börje

1993-01-01

Core-level energy shifts for the beryllium surface region are calculated by means of a Green’s function technique within the tight-binding linear muffin-tin orbitals method. Both initial- and final-state effects in the core-ionization process are fully accounted for. Anomalously large energy shifts...

Molecular-level chemistry of model single-crystal oxide surfaces with model halogenated compounds

Science.gov (United States)

Adib, Kaveh

Synchrotron-based X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD) and low energy electron diffraction (LEED) have been used to investigate, at a molecular level, the chemistry of different terminations of single crystal iron-oxide surfaces with probe molecules (CCl4 and D2O). Comparisons of the reactivity of these surfaces towards CCl4, indicate that the presence of an uncapped surface Fe cation (strong Lewis acid site) and an adjacent oxygen site capped by that cation can effect the C-Cl bond cleavage in CCl4, resulting in dissociatively adsorbed Cl-adatoms and carbon-containing fragments. If in addition to these sites, an uncapped surface oxygen (Lewis base) site is also available, the carbon-containing moiety can then move that site, coordinate itself with that uncapped oxygen, and stabilize itself. At a later step, the carbon-containing fragment may form a strong covalent bond with the uncapped oxygen and may even abstract that surface oxygen. On the other hand, if an uncapped oxygen is not available to stabilize the carbon-containing fragment, the surface coordination will not occur and upon the subsequent thermal annealing of the surface the Cl-adatoms and the carbon-containing fragments will recombine and desorb as CCl4. Finally, the presence of surface deuteroxyls blocking the strong Lewis acid and base sites of the reactive surface, passivates this surface. Such a deuteroxylated surface will be unreactive towards CCl 4. Such a molecular level understanding of the surface chemistry of metal-oxides will have applications in the areas of selective catalysis, including environmental catalysis, and chemical sensor technology.

Spatially-varying surface roughness and ground-level air quality in an operational dispersion model

International Nuclear Information System (INIS)

Barnes, M.J.; Brade, T.K.; MacKenzie, A.R.; Whyatt, J.D.; Carruthers, D.J.; Stocker, J.; Cai, X.; Hewitt, C.N.

2014-01-01

Urban form controls the overall aerodynamic roughness of a city, and hence plays a significant role in how air flow interacts with the urban landscape. This paper reports improved model performance resulting from the introduction of variable surface roughness in the operational air-quality model ADMS-Urban (v3.1). We then assess to what extent pollutant concentrations can be reduced solely through local reductions in roughness. The model results suggest that reducing surface roughness in a city centre can increase ground-level pollutant concentrations, both locally in the area of reduced roughness and downwind of that area. The unexpected simulation of increased ground-level pollutant concentrations implies that this type of modelling should be used with caution for urban planning and design studies looking at ventilation of pollution. We expect the results from this study to be relevant for all atmospheric dispersion models with urban-surface parameterisations based on roughness. -- Highlights: • Spatially variable roughness improved performance of an operational model. • Scenario modelling explored effect of reduced roughness on air pollution. • Reducing surface roughness can increase modelled ground-level pollution. • Damped vertical mixing outweighs increased horizontal advection in model study. • Result should hold for any model with a land-surface coupling based on roughness. -- Spatially varying roughness improves model simulations of urban air pollutant dispersion. Reducing roughness does not always decrease ground-level pollution concentrations

An ontology design pattern for surface water features

Science.gov (United States)

Sinha, Gaurav; Mark, David; Kolas, Dave; Varanka, Dalia; Romero, Boleslo E.; Feng, Chen-Chieh; Usery, E. Lynn; Liebermann, Joshua; Sorokine, Alexandre

2014-01-01

Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities exist due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology for other more context-dependent ontologies. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex or specialized surface water ontologies. A fundamental distinction is made in this ontology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is implemented in OWL, but Description Logic axioms and a detailed explanation is provided in this paper. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. Also provided is a discussion of why there is a need to complement the pattern with other ontologies, especially the previously developed Surface Network pattern. Finally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through an annotated geospatial dataset and sample queries using the classes of the Surface Water pattern.

Propagation of waves from an arbitrary shaped surface-A generalization of the Fresnel diffraction integral

Science.gov (United States)

Feshchenko, R. M.; Vinogradov, A. V.; Artyukov, I. A.

2018-04-01

Using the method of Laplace transform the field amplitude in the paraxial approximation is found in the two-dimensional free space using initial values of the amplitude specified on an arbitrary shaped monotonic curve. The obtained amplitude depends on one a priori unknown function, which can be found from a Volterra first kind integral equation. In a special case of field amplitude specified on a concave parabolic curve the exact solution is derived. Both solutions can be used to study the light propagation from arbitrary surfaces including grazing incidence X-ray mirrors. They can find applications in the analysis of coherent imaging problems of X-ray optics, in phase retrieval algorithms as well as in inverse problems in the cases when the initial field amplitude is sought on a curved surface.

Surface geometry of protoplanetary disks inferred from near-infrared imaging polarimetry

Energy Technology Data Exchange (ETDEWEB)

Takami, Michihiro; Hasegawa, Yasuhiro; Gu, Pin-Gao; Karr, Jennifer L.; Chapillon, Edwige; Tang, Ya-Wen [Institute of Astronomy and Astrophysics, Academia Sinica, PO Box 23-141, Taipei 10617, Taiwan, ROC (China); Muto, Takayuki [Division of Liberal Arts, Kogakuin University, 1-24-2, Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677 (Japan); Dong, Ruobing [Nuclear Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Hashimoto, Jun [H. L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St. Norman, OK 73019 (United States); Kusakabe, Nobuyuki; Akiyama, Eiji; Kwon, Jungmi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Itoh, Youchi [Nishi-Harima Astronomical Observatory, Center for Astronomy, University of Hyogo, 407-2 Nishigaichi, Sayo, Sayo, Hyogo 679-5313 (Japan); Carson, Joseph [Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States); Follette, Katherine B. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Mayama, Satoshi [The Center for the Promotion of Integrated Sciences, The Graduate University for Advanced Studies (SOKENDAI), Shonan International Village, Hayama-cho, Miura-gun, Kanagawa 240-0193 (Japan); Sitko, Michael [Department of Physics, University of Cincinnati, Cincinnati, OH 45221 (United States); Janson, Markus [Astrophysics Research Center, Queen' s University Belfast, BT7 1NN (United Kingdom); Grady, Carol A. [Eureka Scientific, 2452 Delmer Suite 100, Oakland, CA 96402 (United States); Kudo, Tomoyuki, E-mail: hiro@asiaa.sinica.edu.tw [Subaru Telescope, 650 North Aohoku Place, Hilo, HI 96720 (United States); and others

2014-11-01

We present a new method of analysis for determining the surface geometry of five protoplanetary disks observed with near-infrared imaging polarimetry using Subaru-HiCIAO. Using as inputs the observed distribution of polarized intensity (PI), disk inclination, assumed properties for dust scattering, and other reasonable approximations, we calculate a differential equation to derive the surface geometry. This equation is numerically integrated along the distance from the star at a given position angle. We show that, using these approximations, the local maxima in the PI distribution of spiral arms (SAO 206462, MWC 758) and rings (2MASS J16042165-2130284, PDS 70) are associated with local concave-up structures on the disk surface. We also show that the observed presence of an inner gap in scattered light still allows the possibility of a disk surface that is parallel to the light path from the star, or a disk that is shadowed by structures in the inner radii. Our analysis for rings does not show the presence of a vertical inner wall as often assumed in studies of disks with an inner gap. Finally, we summarize the implications of spiral and ring structures as potential signatures of ongoing planet formation.

Surface geometry of protoplanetary disks inferred from near-infrared imaging polarimetry

International Nuclear Information System (INIS)

Takami, Michihiro; Hasegawa, Yasuhiro; Gu, Pin-Gao; Karr, Jennifer L.; Chapillon, Edwige; Tang, Ya-Wen; Muto, Takayuki; Dong, Ruobing; Hashimoto, Jun; Kusakabe, Nobuyuki; Akiyama, Eiji; Kwon, Jungmi; Itoh, Youchi; Carson, Joseph; Follette, Katherine B.; Mayama, Satoshi; Sitko, Michael; Janson, Markus; Grady, Carol A.; Kudo, Tomoyuki

2014-01-01

We present a new method of analysis for determining the surface geometry of five protoplanetary disks observed with near-infrared imaging polarimetry using Subaru-HiCIAO. Using as inputs the observed distribution of polarized intensity (PI), disk inclination, assumed properties for dust scattering, and other reasonable approximations, we calculate a differential equation to derive the surface geometry. This equation is numerically integrated along the distance from the star at a given position angle. We show that, using these approximations, the local maxima in the PI distribution of spiral arms (SAO 206462, MWC 758) and rings (2MASS J16042165-2130284, PDS 70) are associated with local concave-up structures on the disk surface. We also show that the observed presence of an inner gap in scattered light still allows the possibility of a disk surface that is parallel to the light path from the star, or a disk that is shadowed by structures in the inner radii. Our analysis for rings does not show the presence of a vertical inner wall as often assumed in studies of disks with an inner gap. Finally, we summarize the implications of spiral and ring structures as potential signatures of ongoing planet formation.

New configuration factors for curved surfaces

International Nuclear Information System (INIS)

Cabeza-Lainez, Jose M.; Pulido-Arcas, Jesus A.

2013-01-01

Curved surfaces have not been thoroughly considered in radiative transfer analysis mainly due to the difficulties arisen in the integration process and perhaps because of the lack of spatial vision of the researchers. It is a fact, especially for architectural lighting, that when concave geometries appear inside a curved space, they are mostly avoided. In this way, a vast repertoire of significant forms is neglected and energy waste is evident. Starting from the properties of volumes enclosed by the minimum number of surfaces, the authors formulate, with little calculus, new simple laws, which enable them to discover a set of configuration factors for caps and various segments of the sphere. The procedure is subsequently extended to previously unimagined surfaces as the paraboloid, the ellipsoid or the cone. Appropriate combination of the said forms with right truncated cones produces several complex volumes, often used in architectural and engineering creations and whose radiative performance could not be accurately predicted for decades. To complete the research, a new method for determining interreflections in curved volumes is also presented. Radiative transfer simulation benefits from these findings, as the simplicity of the results has led the authors to create innovative software more efficient for design and evaluation and applicable to emerging fields like LED lighting. -- Highlights: ► Friendly revision of fundamentals of radiative transfer. ► New configuration factors for curved surfaces obtained without calculus. ► New method for interreflections in curved geometries. ► Enhanced simulation algorithms. ► Fast comparison of radiative performances of surfaces

The Influence of As-Built Surface Conditions on Mechanical Properties of Ti-6Al-4V Additively Manufactured by Selective Electron Beam Melting

Science.gov (United States)

Sun, Y. Y.; Gulizia, S.; Oh, C. H.; Fraser, D.; Leary, M.; Yang, Y. F.; Qian, M.

2016-03-01

Achieving a high surface finish is a major challenge for most current metal additive manufacturing processes. We report the first quantitative study of the influence of as-built surface conditions on the tensile properties of Ti-6Al-4V produced by selective electron beam melting (SEBM) in order to better understand the SEBM process. Tensile ductility was doubled along with noticeable improvements in tensile strengths after surface modification of the SEBM-fabricated Ti-6Al-4V by chemical etching. The fracture surfaces of tensile specimens with different surface conditions were characterised and correlated with the tensile properties obtained. The removal of a 650- μm-thick surface layer by chemical etching was shown to be necessary to eliminate the detrimental influence of surface defects on mechanical properties. The experimental results and analyses underline the necessity to modify the surfaces of SEBM-fabricated components for structural applications, particularly for those components which contain complex internal concave and convex surfaces and channels.

Left-Right Asymmetric Morphogenesis in the Xenopus Digestive System

Science.gov (United States)

Muller, Jennifer K.; Prather, D.R.; Nascone-Yoder, N. M.

2003-01-01

The morphogenetic mechanisms by which developing organs become left-right asymmetric entities are unknown. To investigate this issue, we compared the roles of the left and right sides of the Xenopus embryo during the development of anatomic asymmetries in the digestive system. Although both sides contribute equivalently to each of the individual digestive organs, during the initial looping of the primitive gut tube, the left side assumes concave topologies where the right side becomes convex. Of interest, the concave surfaces of the gut tube correlate with expression of the LR gene, Pitx2, and ectopic Pitx2 mRNA induces ectopic concavities in a localized manner. A morphometric comparison of the prospective concave and convex surfaces of the gut tube reveals striking disparities in their rate of elongation but no significant differences in cell proliferation. These results provide insight into the nature of symmetry-breaking morphogenetic events during left-right asymmetric organ development. ?? 2003 Wiley-Liss, Inc.

Fabrication of hydrophobic structures on coronary stent surface based on direct three-beam laser interference lithography

Science.gov (United States)

Gao, Long-yue; Zhou, Wei-qi; Wang, Yuan-bo; Wang, Si-qi; Bai, Chong; Li, Shi-ming; Liu, Bin; Wang, Jun-nan; Cui, Cheng-kun; Li, Yong-liang

2016-05-01

To solve the problems with coronary stent implantation, coronary artery stent surface was directly modified by three-beam laser interference lithography through imitating the water-repellent surface of lotus leaf, and uniform micro-nano structures with the controllable period were fabricated. The morphological properties and contact angle (CA) of the microstructure were measured by scanning electron microscope (SEM) and CA system. The water repellency of stent was also evaluated by the contact and then separation between the water drop and the stent. The results show that the close-packed concave structure with the period of about 12 μm can be fabricated on the stent surface with special parameters (incident angle of 3°, laser energy density of 2.2 J·cm-2 and exposure time of 80 s) by using the three-beam laser at 1 064 nm, and the structure has good water repellency with CA of 120°.

GHRSST Level 4 DMI_OI Global Foundation Sea Surface Temperature Analysis (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the Danish...

Surface tension-induced PDMS micro-pillars with controllable tips and tilt angles

KAUST Repository

Li, Huawei; Fan, Yiqiang; Conchouso Gonzalez, David; Foulds, Ian G.

2013-01-01

This paper reports a novel method to fabricate three-dimensional (3D) polydimethylsiloxane (PDMS) micro-pillars using a CO2 laser-machined poly(methyl methacrylate) (PMMA) mold with through-holes. This method eliminates the requirements of expensive and complicated facilities to fabricate a 3D mold. The micro-pillars were formed by the capillary force that draws PDMS into the through-holes of the PMMA mold. The tilt angles of the micro-pillars depend on the tilt angles of the through-holes in the mold, and the concave and convex micro-lens tip shapes of the PDMS micro-pillars can be modified by changing the surface wettability of the PMMA through-holes.

Surface tension-induced PDMS micro-pillars with controllable tips and tilt angles

KAUST Repository

Li, Huawei

2013-12-21

This paper reports a novel method to fabricate three-dimensional (3D) polydimethylsiloxane (PDMS) micro-pillars using a CO2 laser-machined poly(methyl methacrylate) (PMMA) mold with through-holes. This method eliminates the requirements of expensive and complicated facilities to fabricate a 3D mold. The micro-pillars were formed by the capillary force that draws PDMS into the through-holes of the PMMA mold. The tilt angles of the micro-pillars depend on the tilt angles of the through-holes in the mold, and the concave and convex micro-lens tip shapes of the PDMS micro-pillars can be modified by changing the surface wettability of the PMMA through-holes.

Influence of surface pre-treatment on the electronic levels in silicon MaWCE nanowires.

Science.gov (United States)

Venturi, Giulia; Castaldini, Antonio; Schleusener, Alexander; Sivakov, Vladimir; Cavallini, Anna

2015-05-15

Deep level transient spectroscopy (DLTS) was performed on n-doped silicon nanowires grown by metal-assisted wet chemical etching (MaWCE) with gold as the catalyst in order to investigate the energetic scheme inside the bandgap. To observe the possible dependence of the level scheme on the processing temperature, DLTS measurements were performed on the nanowires grown on a non-treated Au/Si surface and on a thermally pre-treated Au/Si surface. A noticeable modification of the configuration of the energy levels was observed, induced by the annealing process. Based on our results on these MaWCE nanowires and on literature data about deep levels in bulk silicon, some hypotheses were advanced regarding the identification of the defects responsible of the energy levels revealed.

GHRSST Level 4 OSPO Global Nighttime Foundation Sea Surface Temperature Analysis (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Office of...

GHRSST Level 4 RAMSSA Australian Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Australian Bureau...

An Ontology Design Pattern for Surface Water Features

Energy Technology Data Exchange (ETDEWEB)

Sinha, Gaurav [Ohio University; Mark, David [University at Buffalo (SUNY); Kolas, Dave [Raytheon BBN Technologies; Varanka, Dalia [U.S. Geological Survey, Rolla, MO; Romero, Boleslo E [University of California, Santa Barbara; Feng, Chen-Chieh [National University of Singapore; Usery, Lynn [U.S. Geological Survey, Rolla, MO; Liebermann, Joshua [Tumbling Walls, LLC; Sorokine, Alexandre [ORNL

2014-01-01

Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities can be found due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology. It can then be used to systematically incor-porate concepts that are specific to a culture, language, or scientific domain. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex surface water ontologies. A fundamental distinction is made in this on-tology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is imple-mented in OWL, but Description Logic axioms and a detailed explanation is provided. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. A discussion about why there is a need to complement the pattern with other ontologies, es-pecially the previously developed Surface Network pattern is also provided. Fi-nally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through a few queries and annotated geospatial datasets.

On the Problem of Determining Aggregation Numbers from Surface Tension Measurements.

Science.gov (United States)

Rusanov, Anatoly I

2017-11-07

In view of the recent discovery of variable aggregation numbers in the vicinity of the critical micelle concentration (CMC), the mass-action-law theory of the surface tension isotherm of a micellar solution with variable aggregation numbers is formulated both for nonionic and ionic surfactants. It is shown that the shape of the surface tension isotherm should be concave in the logarithmic scale above the CMC. Considering a change in the isotherm slope at the CMC apparent break point, the problems of determining the aggregation number for nonionic micelles and the degree of counterion binding for ionic micelles are discussed. In case of the aggregation number variability near the CMC, finding the aggregation number above the CMC apparent break point is considered and a computational scheme is elaborated, requiring a higher precision for experiment. Some experimental data from the literature are analyzed, and the method of estimating the degree of counterion binding is improved.

GHRSST Level 4 MW_OI Global Foundation Sea Surface Temperature analysis (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) global Level 4 sea surface temperature analysis produced daily on a 0.25 degree grid at Remote Sensing...

Active surface model improvement by energy function optimization for 3D segmentation.

Science.gov (United States)

Azimifar, Zohreh; Mohaddesi, Mahsa

2015-04-01

This paper proposes an optimized and efficient active surface model by improving the energy functions, searching method, neighborhood definition and resampling criterion. Extracting an accurate surface of the desired object from a number of 3D images using active surface and deformable models plays an important role in computer vision especially medical image processing. Different powerful segmentation algorithms have been suggested to address the limitations associated with the model initialization, poor convergence to surface concavities and slow convergence rate. This paper proposes a method to improve one of the strongest and recent segmentation algorithms, namely the Decoupled Active Surface (DAS) method. We consider a gradient of wavelet edge extracted image and local phase coherence as external energy to extract more information from images and we use curvature integral as internal energy to focus on high curvature region extraction. Similarly, we use resampling of points and a line search for point selection to improve the accuracy of the algorithm. We further employ an estimation of the desired object as an initialization for the active surface model. A number of tests and experiments have been done and the results show the improvements with regards to the extracted surface accuracy and computational time of the presented algorithm compared with the best and recent active surface models. Copyright © 2015 Elsevier Ltd. All rights reserved.

Radiographic detection of single-leg fracture in Björk-Shiley Convexo-Concave prosthetic valves: a phantom model study.

Science.gov (United States)

Gilchrist, I C; Cardella, J F; Fox, P S; Pae, W E; el-Ghamry Sabe, A A; Landis, J R; Localio, A R; Kunselman, A R; Hopper, K D

1997-02-01

Cineradiography can identify patients with single-leg fractured Björk-Shiley Convexo-Concave valves, although little is known about the sensitivity and specificity of this technique. We evaluated three normal and six (0 microm gap) single-leg fractured Björk-Shiley valves that were placed in a working phantom model. Valves were randomly imaged a total of 33 times and duplicated into a 120-valve series with a 1:9 ratio of abnormal/normal valves. Six reviewers independently graded each valve and demonstrated markedly different rates of identifying the fractured valves. Average sensitivity at the grade that clinically results in valve explanation was 47%. Among the normal valves, a correct identification was made 96% (range 91% to 99%) of the time. Present radiographic technology may have significant difficulty in identifying true single-leg fracture in Björk-Shiley valves with limb separations that are common among clinically explanted valves.

Strong compensation hinders the p-type doping of ZnO: a glance over surface defect levels

Science.gov (United States)

Huang, B.

2016-07-01

We propose a surface doping model of ZnO to elucidate the p-type doping and compensations in ZnO nanomaterials. With an N-dopant, the effects of N on the ZnO surface demonstrate a relatively shallow acceptor level in the band gap. As the dimension of the ZnO materials decreases, the quantum confinement effects will increase and render the charge transfer on surface to influence the shifting of Fermi level, by evidence of transition level changes of the N-dopant. We report that this can overwhelm the intrinsic p-type conductivity and transport of the ZnO bulk system. This may provide a possible route of using surface doping to modify the electronic transport and conductivity of ZnO nanomaterials.

Levels of surface contamination with radioactive materials at workplaces of nuclear research centre at Rez

International Nuclear Information System (INIS)

Hoelgye, Z.; Nemcova, I.; Kasikova, M.; Popper, J.; Chysky, J.

1983-01-01

A hygiene supervision unit at workplaces of the nuclear Research Institute in Rez monitored on a long-term basis surface contamination with radioactive substances. Surface contamination was found at workplaces with open sources. Of the 4343 monitored places action levels were only exceeded in 13 cases. The obtained data were used for typifying workplaces with the highest level of surface contamination, to determine in certain instances the mechanism of the escape of radioactive substances from insulating facilities and to determine the rate of the spread of the radioactive substance into adjacent non-active workplaces. (author)

Tarantula toxins use common surfaces for interacting with Kv and ASIC ion channels.

Science.gov (United States)

Gupta, Kanchan; Zamanian, Maryam; Bae, Chanhyung; Milescu, Mirela; Krepkiy, Dmitriy; Tilley, Drew C; Sack, Jon T; Yarov-Yarovoy, Vladimir; Kim, Jae Il; Swartz, Kenton J

2015-05-07

Tarantula toxins that bind to voltage-sensing domains of voltage-activated ion channels are thought to partition into the membrane and bind to the channel within the bilayer. While no structures of a voltage-sensor toxin bound to a channel have been solved, a structural homolog, psalmotoxin (PcTx1), was recently crystalized in complex with the extracellular domain of an acid sensing ion channel (ASIC). In the present study we use spectroscopic, biophysical and computational approaches to compare membrane interaction properties and channel binding surfaces of PcTx1 with the voltage-sensor toxin guangxitoxin (GxTx-1E). Our results show that both types of tarantula toxins interact with membranes, but that voltage-sensor toxins partition deeper into the bilayer. In addition, our results suggest that tarantula toxins have evolved a similar concave surface for clamping onto α-helices that is effective in aqueous or lipidic physical environments.

Application of identifying transmission spheres for spherical surface testing

Science.gov (United States)

Han, Christopher B.; Ye, Xin; Li, Xueyuan; Wang, Quanzhao; Tang, Shouhong; Han, Sen

2017-06-01

We developed a new application on Microsoft Foundation Classes (MFC) to identify correct transmission spheres (TS) for Spherical Surface Testing (SST). Spherical surfaces are important optical surfaces, and the wide application and high production rate of spherical surfaces necessitates an accurate and highly reliable measuring device. A Fizeau Interferometer is an appropriate tool for SST due to its subnanometer accuracy. It measures the contour of a spherical surface using a common path, which is insensitive to the surrounding circumstances. The Fizeau Interferometer transmits a wide laser beam, creating interference fringes from re-converging light from the transmission sphere and the test surface. To make a successful measurement, the application calculates and determines the appropriate transmission sphere for the test surface. There are 3 main inputs from the test surfaces that are utilized to determine the optimal sizes and F-numbers of the transmission spheres: (1) the curvatures (concave or convex), (2) the Radii of Curvature (ROC), and (3) the aperture sizes. The application will firstly calculate the F-numbers (i.e. ROC divided by aperture) of the test surface, secondly determine the correct aperture size of a convex surface, thirdly verify that the ROC of the test surface must be shorter than the reference surface's ROC of the transmission sphere, and lastly calculate the percentage of area that the test surface will be measured. However, the amount of interferometers and transmission spheres should be optimized when measuring large spherical surfaces to avoid requiring a large amount of interferometers and transmission spheres for each test surface. Current measuring practices involve tedious and potentially inaccurate calculations. This smart application eliminates human calculation errors, optimizes the selection of transmission spheres (including the least number required) and interferometer sizes, and increases efficiency.

Paramphistomum cervi: surface topography of the tegument of adult fluke.

Science.gov (United States)

Panyarachun, Busaba; Sobhon, Prasert; Tinikul, Yotsawan; Chotwiwatthanakun, Charoonroj; Anupunpisit, Vipavee; Anuracpreeda, Panat

2010-06-01

Adult Paramphistomum cervi or rumen fluke are pear-shaped, slightly concave ventrally and convex dorsally. The worm measures about 5-13 mm in length and 2-5 mm in width across the mid-section. As observed by scanning electron microscopy (SEM), the tegumental surface in all part of the body, appears highly corrugated with transverse folds alternating with grooves and is spineless. At high magnification, the surface of the fold is composed of microfolds or ridges separated by microgrooves or pits. Corrugations and invaginations of the ventral surface are also more extensive than on the dorsal surface of the body. Both anterior and posterior suckers have thick rims covered with transverse folds without spine. The genital pore is situated at the anterior third of the body. There are two types of sensory papillae on the surface: type 1 is bulbous in shape, measuring 10-15 microm in diameter at the base with nipple-like tips, and type 2 has a similar shape and size and also a short cilia on top. These sensory papillae usually occur in large clusters, each having between 5 and 20 units depending on the region of the body. Clusters of papillae on the ventral surface and around the anterior suckers tend to be more numerous and larger in size. The dorsal surface of the body has the least number of papillae. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Quadrilateral mesh fitting that preserves sharp features based on multi-normals for Laplacian energy

Directory of Open Access Journals (Sweden)

Yusuke Imai

2014-04-01

Full Text Available Because the cost of performance testing using actual products is expensive, manufacturers use lower-cost computer-aided design simulations for this function. In this paper, we propose using hexahedral meshes, which are more accurate than tetrahedral meshes, for finite element analysis. We propose automatic hexahedral mesh generation with sharp features to precisely represent the corresponding features of a target shape. Our hexahedral mesh is generated using a voxel-based algorithm. In our previous works, we fit the surface of the voxels to the target surface using Laplacian energy minimization. We used normal vectors in the fitting to preserve sharp features. However, this method could not represent concave sharp features precisely. In this proposal, we improve our previous Laplacian energy minimization by adding a term that depends on multi-normal vectors instead of using normal vectors. Furthermore, we accentuate a convex/concave surface subset to represent concave sharp features.

The need for national diagnostic reference levels: entrance surface dose measurement in intraoral radiography

International Nuclear Information System (INIS)

Mortazavi, S. M. J.; Shareghi, A.; Kavousi, A.; Ghiassi-Nejad, M.; Jafari-Zadeh, M.; Nazeri, F.; Mozdarani, H.

2004-01-01

Background: Intraoral radiographies are the most frequent X-ray examinations in humans. According to International Commission on Radiation Protection recommendations, the selection of a diagnostic reference level should be specific to a country or region. Critical organs such as thyroid gland are exposed to X-rays in intraoral radiography and these exposures should be kept as low as reasonably achievable. To assist the development of DRLs for intraoral radiography, a National Radiation Protection Department-sponsored pilot study was carried out. Materials and methods: thermoluminescent dosimetry is widely acknowledged to be the recommended method for measuring entrance surface doses. In this study, entrance surface doses was measured using LiF thermoluminescent dosimeters on the skin (either mandibular or maxillary arcs) of 40 patients. Three thermoluminescent dosimetry chips were placed on the skin of each patient. The doses were averaged for each radiography and mean entrance surface doses of all patients calculated. Results: the mean ±SD entrance surface dose at the center of the beam on the patient's skin in intraoral radiography was 1.173 ±0.606 mGy (ranged from 0.01 o 0.40 m Gy). The mean entrance surface doses for male and female patients were 1.380± 0.823, and 1.004± 0.258 respectively. No statistically significant difference was found between these means. Despite its necessity , in national level , there is no published data on the diagnostic reference levels for intraoral radiography. However, the results obtained in this study are lower than those reported by investigators in other countries. Conclusion: in IR Iran , due to lack of large scale studies, no diagnostic reference levels have been set for X-ray diagnostic procedures. Due to lack of national diagnostic reference levels, it is not possible to clarify whether in intraoral radiographies any dose reduction techniques are needed. We intend to perform similar nationwide studies to set the

Comparisons of predicted steady-state levels in rooms with extended- and local-reaction bounding surfaces

Science.gov (United States)

Hodgson, Murray; Wareing, Andrew

2008-01-01

A combined beam-tracing and transfer-matrix model for predicting steady-state sound-pressure levels in rooms with multilayer bounding surfaces was used to compare the effect of extended- and local-reaction surfaces, and the accuracy of the local-reaction approximation. Three rooms—an office, a corridor and a workshop—with one or more multilayer test surfaces were considered. The test surfaces were a single-glass panel, a double-drywall panel, a carpeted floor, a suspended-acoustical ceiling, a double-steel panel, and glass fibre on a hard backing. Each test surface was modeled as of extended or of local reaction. Sound-pressure levels were predicted and compared to determine the significance of the surface-reaction assumption. The main conclusions were that the difference between modeling a room surface as of extended or of local reaction is not significant when the surface is a single plate or a single layer of material (solid or porous) with a hard backing. The difference is significant when the surface consists of multilayers of solid or porous material and includes a layer of fluid with a large thickness relative to the other layers. The results are partially explained by considering the surface-reflection coefficients at the first-reflection angles.

Correlation of Cell Surface Biomarker Expression Levels with Adhesion Contact Angle Measured by Lateral Microscopy.

Science.gov (United States)

Walz, Jenna A; Mace, Charles R

2018-06-05

Immunophenotyping is typically achieved using flow cytometry, but any influence a biomarker may have on adhesion or surface recognition cannot be determined concurrently. In this manuscript, we demonstrate the utility of lateral microscopy for correlating cell surface biomarker expression levels with quantitative descriptions of cell morphology. With our imaging system, we observed single cells from two T cell lines and two B cell lines adhere to antibody-coated substrates and quantified this adhesion using contact angle measurements. We found that SUP-T1 and CEM CD4+ cells, both of which express similar levels of CD4, experienced average changes in contact angle that were not statistically different from one another on surfaces coated in anti-CD4. However, MAVER-1 and BJAB K20 cells, both of which express different levels of CD20, underwent average changes in contact angle that were significantly different from one another on surfaces coated in anti-CD20. Our results indicate that changes in cell contact angles on antibody-coated substrates reflect the expression levels of corresponding antigens on the surfaces of cells as determined by flow cytometry. Our lateral microscopy approach offers a more reproducible and quantitative alternative to evaluate adhesion compared to commonly used wash assays and can be extended to many additional immunophenotyping applications to identify cells of interest within heterogeneous populations.

Probability distribution for the Gaussian curvature of the zero level surface of a random function

Science.gov (United States)

Hannay, J. H.

2018-04-01

A rather natural construction for a smooth random surface in space is the level surface of value zero, or ‘nodal’ surface f(x,y,z)  =  0, of a (real) random function f; the interface between positive and negative regions of the function. A physically significant local attribute at a point of a curved surface is its Gaussian curvature (the product of its principal curvatures) because, when integrated over the surface it gives the Euler characteristic. Here the probability distribution for the Gaussian curvature at a random point on the nodal surface f  =  0 is calculated for a statistically homogeneous (‘stationary’) and isotropic zero mean Gaussian random function f. Capitalizing on the isotropy, a ‘fixer’ device for axes supplies the probability distribution directly as a multiple integral. Its evaluation yields an explicit algebraic function with a simple average. Indeed, this average Gaussian curvature has long been known. For a non-zero level surface instead of the nodal one, the probability distribution is not fully tractable, but is supplied as an integral expression.

Estimation of surface UV levels based on Meteor-3/TOMS ozone data

Energy Technology Data Exchange (ETDEWEB)

Borisov, Y A [Central Aerological Observatory, Moscow (Russian Federation); Geogdzhaev, I V [Moscow Inst. of Physics and Technology, Moscow (Russian Federation); Khattatov, V U [Central Aerological Observatory, Moscow (Russian Federation)

1996-12-31

The major consequence of ozone layer depletion for the environment is an increase of harmful ultraviolet (UV) radiation on the Earth surface and in the upper ocean. This implies the importance of environmental UV monitoring. Since the direct global monitoring is not currently possible, indirect estimations of surface UV levels may be used based on satellite ozone data (Madronich, S. 1992). Total Ozone Mapping Spectrometer (TOMS) on board the METEOR-3 satellite provided regular set of data for such estimates. During the time of its operation (August, 1991 - December, 1994) the instrument registered several ozone hole events over Antarctica, when ozone levels dropped by as much as 60 % from their unperturbed values. Probably even more alarming ozone depletions were observed over highly populated regions of middle latitudes of northern hemisphere. Radiative transfer modeling was used to convert METEOR-3/TOMS daily ozone values into regional and global maps of biologically active UV. Calculations demonstrate the effect on surface UV levels produced by ozone hole over Antarctica and ozone depletions over the territory of Russia (March, 1994). UV contour lines deviate from the normal appearance which is determined by growing southward solar elevation. UV contour lines are almost perpendicular to the ozone ones in the ozone depletions areas. The 30 % ozone depletion, over Siberia caused more than 30 % increase in noontime erythemal UV levels, which is equivalent to 10-15 degrees southward latitude displacement. Higher UV radiation increases were found in ozone hole over South America (October 1992) equivalent to about 20 degrees southward displacement

Estimation of surface UV levels based on Meteor-3/TOMS ozone data

Energy Technology Data Exchange (ETDEWEB)

Borisov, Y.A. [Central Aerological Observatory, Moscow (Russian Federation); Geogdzhaev, I.V. [Moscow Inst. of Physics and Technology, Moscow (Russian Federation); Khattatov, V.U. [Central Aerological Observatory, Moscow (Russian Federation)

1995-12-31

The major consequence of ozone layer depletion for the environment is an increase of harmful ultraviolet (UV) radiation on the Earth surface and in the upper ocean. This implies the importance of environmental UV monitoring. Since the direct global monitoring is not currently possible, indirect estimations of surface UV levels may be used based on satellite ozone data (Madronich, S. 1992). Total Ozone Mapping Spectrometer (TOMS) on board the METEOR-3 satellite provided regular set of data for such estimates. During the time of its operation (August, 1991 - December, 1994) the instrument registered several ozone hole events over Antarctica, when ozone levels dropped by as much as 60 % from their unperturbed values. Probably even more alarming ozone depletions were observed over highly populated regions of middle latitudes of northern hemisphere. Radiative transfer modeling was used to convert METEOR-3/TOMS daily ozone values into regional and global maps of biologically active UV. Calculations demonstrate the effect on surface UV levels produced by ozone hole over Antarctica and ozone depletions over the territory of Russia (March, 1994). UV contour lines deviate from the normal appearance which is determined by growing southward solar elevation. UV contour lines are almost perpendicular to the ozone ones in the ozone depletions areas. The 30 % ozone depletion, over Siberia caused more than 30 % increase in noontime erythemal UV levels, which is equivalent to 10-15 degrees southward latitude displacement. Higher UV radiation increases were found in ozone hole over South America (October 1992) equivalent to about 20 degrees southward displacement

Electron mobility on the surface of liquid Helium: influence of surface level atoms and depopulation of lowest subbands

International Nuclear Information System (INIS)

Grigoriev, P. D.; Dyugaev, A. M.; Lebedeva, E. V.

2008-01-01

The temperature dependence of electron mobility is examined. We calculate the contribution to the electron scattering rate from the surface level atoms (SLAs), proposed in [10]. This contribution is substantial at low temperatures T < 0.5, when the He vapor concentration is exponentially small. We also study the effect of depopulation of the lowest energy subband, which leads to an increase in the electron mobility at high temperature. The results explain certain long-standing discrepancies between the existing theory and experiment on electron mobility on the surface of liquid helium

Elevation of Matrix Metalloproteinases in Different Areas of Ascending Aortic Aneurysms in Patients with Bicuspid and Tricuspid Aortic Valves

Directory of Open Access Journals (Sweden)

Salah A. Mohamed

2012-01-01

Full Text Available Our aim is to investigate the elevation of matrix proteins in tissues obtained from distal, above the sinotubular junction (proximal, concave, and convex sites of aneurysms in the ascending aorta using a simultaneous multiplex protein detection system. Tissues were collected from 41 patients with ascending aortic aneurysms. A total of 31 patients had a bicuspid aortic valve (BAV, whereas 10 had a tricuspid aortic valve (TAV. Concave and convex aortic site samples were collected from all patients, whereas proximal and distal convexity samples were obtained from 19 patients with BAV and 7 patients with TAV. Simultaneous detection of matrix metalloproteinases (MMPs and their inhibitors (TIMPs was performed at each of the four aortic sites. MMP-2 levels were higher in the concave aortic sites than in the convex aortic sites. In contrast, MMP-8 levels were higher in the convex sites than in the concave sites, as were MMP-9 levels. In both BAV and TAV patients, TIMP-3 levels were higher in the concave sites than in the convex sites. However, TIMP-2 and TIMP-4 levels were significantly elevated in the sinotubular proximal aorta of BAV patients. Simultaneous detection of MMPs and TIMPs revealed different levels at different aortic sites in the same patient.

GHRSST Level 4 EUR Mediterranean Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily by Ifremer/CERSAT (France) using optimal...

GHRSST Level 4 MUR North America Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced as a retrospective dataset at the JPL Physical...

GHRSST Level 4 ODYSSEA Mediterranean Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

An automated three-dimensional detection and segmentation method for touching cells by integrating concave points clustering and random walker algorithm.

Directory of Open Access Journals (Sweden)

Yong He

Full Text Available Characterizing cytoarchitecture is crucial for understanding brain functions and neural diseases. In neuroanatomy, it is an important task to accurately extract cell populations' centroids and contours. Recent advances have permitted imaging at single cell resolution for an entire mouse brain using the Nissl staining method. However, it is difficult to precisely segment numerous cells, especially those cells touching each other. As presented herein, we have developed an automated three-dimensional detection and segmentation method applied to the Nissl staining data, with the following two key steps: 1 concave points clustering to determine the seed points of touching cells; and 2 random walker segmentation to obtain cell contours. Also, we have evaluated the performance of our proposed method with several mouse brain datasets, which were captured with the micro-optical sectioning tomography imaging system, and the datasets include closely touching cells. Comparing with traditional detection and segmentation methods, our approach shows promising detection accuracy and high robustness.

Radiation levels in the poll surface of IEA-R1 reactor

International Nuclear Information System (INIS)

Pasqualetto, H.

1978-01-01

A theoretical model for the calculation of the radioactivity level in the pool surface of the research reactor IEA-RI (INSTITUTO DE ENERGIA ATOMICA, BRAZIL) is developed. The radioactivity is caused by radionuclides (Mainly 24 Na and 27 Mg) produced by nuclear reactions of neutrons with: a) oxygen of the water b); gaseous elements dissolved in water (Ar,N); c) structural materials of the fuel can. Considerations about expected radiation level after eventual increase of reactor power from 2 MW to 10 MW are also presented [pt

GHRSST Level 4 G1SST Global Foundation Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the JPL OurOcean...

GHRSST Level 4 OSTIA Global Foundation Sea Surface Temperature Analysis (GDS versions 1 and 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the UK Met Office...

Calculation of reasonable exemption levels for surface contamination by measuring overall gamma ray

International Nuclear Information System (INIS)

Ogino, Haruyuki; Hattori, Takatoshi

2008-01-01

The present regulation on surface contamination [Bq/cm 2 ] is determined from a simple radiological model for the most hazardous radionuclides (Pu-239 for alpha emitters and Sr-90 for beta emitters) and its extremely conservative model is applied for all other alpha and beta emitters. In this study, reasonable exemption levels for surface contamination are calculated for each radionuclide by adopting an original radiological dose evaluation method for surface contamination that can be applied in radiation safety, transport safety and waste safety. Furthermore, a new concept of judging the exemption by estimating the overall contamination [Bq] on the objects from the measurement of gamma ray has been designed and a reasonable value was derived. We conclude that the overall exemption levels obtained by gamma ray measurement can be one order smaller than those obtained by the conventional method for some radionuclides, such as Mn-54, Co-60, Nb-94, Cs-134, Cs-137, Eu-152 and Eu-154. (author)

Sensitive determination of dopamine levels via surface-enhanced Raman scattering of Ag nanoparticle dimers.

Science.gov (United States)

Yu, Xiantong; He, XiaoXiao; Yang, Taiqun; Zhao, Litao; Chen, Qichen; Zhang, Sanjun; Chen, Jinquan; Xu, Jianhua

2018-01-01

Dopamine (DA) is an important neurotransmitter in the hypothalamus and pituitary gland, which can produce a direct influence on mammals' emotions in midbrain. Additionally, the level of DA is highly related with some important neurologic diseases such as schizophrenia, Parkinson, and Huntington's diseases, etc. In light of the important roles that DA plays in the disease modulation, it is of considerable significance to develop a sensitive and reproducible approach for monitoring DA. The objective of this study was to develop an efficient approach to quantitatively monitor the level of DA using Ag nanoparticle (NP) dimers and enhanced Raman spectroscopy. Ag NP dimers were synthesized for the sensitive detection of DA via surface-enhanced Raman scattering (SERS). Citrate was used as both the capping agent of NPs and sensing agent to DA, which is self-assembled on the surface of Ag NP dimers by reacting with the surface carboxyl group to form a stable amide bond. To improve accuracy and precision, the multiplicative effects model for surface-enhanced Raman spectroscopy was utilized to analyze the SERS assays. A low limits of detection (LOD) of 20 pM and a wide linear response range from 30 pM to 300 nM were obtained for DA quantitative detection. The SERS enhancement factor was theoretically valued at approximately 10 7 by discrete dipole approximation. DA was self-assembled on the citrate capped surface of Ag NPs dimers through the amide bond. The adsorption energy was estimated to be 256 KJ/mol using the Langmuir isotherm model. The density functional theory was used to simulate the spectral characteristics of SERS during the adsorption of DA on the surface of the Ag dimers. Furthermore, to improve the accuracy and precision of quantitative analysis of SERS assays with a multiplicative effects model for surface-enhanced Raman spectroscopy. A LOD of 20 pM DA-level was obtained, and the linear response ranged from 30 pM to 300 nM for quantitative DA detection. The

Radiation dose rate measuring device

International Nuclear Information System (INIS)

Sorber, R.

1987-01-01

A portable device is described for in-field usage for measuring the dose rate of an ambient beta radiation field, comprising: a housing, substantially impervious to beta radiation, defining an ionization chamber and having an opening into the ionization chamber; beta radiation pervious electrically-conductive window means covering the opening and entrapping, within the ionization chamber, a quantity of gaseous molecules adapted to ionize upon impact with beta radiation particles; electrode means disposed within the ionization chamber and having a generally shallow concave surface terminating in a generally annular rim disposed at a substantially close spacing to the window means. It is configured to substantially conform to the window means to define a known beta radiation sensitive volume generally between the window means and the concave surface of the electrode means. The concave surface is effective to substantially fully expose the beta radiation sensitive volume to the radiation field over substantially the full ambient area faced by the window means

GHRSST Level 4 AVHRR_AMSR_OI Global Blended Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) global Level 4 sea surface temperature analysis produced daily on a 0.25 degree grid at the NOAA...

Surface-induced patterns from evaporating droplets of aqueous carbon nanotube dispersions

KAUST Repository

Zeng, Hongbo; Kristiansen, Kai De Lange; Wang, Peng; Bergli, Joakim; Israelachvili, Jacob N.

2011-01-01

Evaporation of aqueous droplets of carbon nanotubes (CNTs) coated with a physisorbed layer of humic acid (HA) on a partially hydrophilic substrate induces the formation of a film of CNTs. Here, we investigate the role that the global geometry of the substrate surfaces has on the structure of the CNT film. On a flat mica or silica surface, the evaporation of a convex droplet of the CNT dispersion induces the well-known "coffee ring", while evaporation of a concave droplet (capillary meniscus) of the CNT dispersion in a wedge of two planar mica sheets or between two crossed-cylinder sheets induces a large area (>mm 2) of textured or patterned films characterized by different short- and long-range orientational and positional ordering of the CNTs. The resulting patterns appear to be determined by two competing or cooperative sedimentation mechanisms: (1) capillary forces between CNTs giving micrometer-sized filaments parallel to the boundary line of the evaporating droplet and (2) fingering instability at the boundary line of the evaporating droplet and subsequent pinning of CNTs on the surface giving micrometer-sized filaments of CNTs perpendicular to this boundary line. The interplay between substrate surface geometry and sedimentation mechanisms gives an extra control parameter for manipulating patterns of self-assembling nanoparticles at substrate surfaces. © 2011 American Chemical Society.

Surface-induced patterns from evaporating droplets of aqueous carbon nanotube dispersions

KAUST Repository

Zeng, Hongbo

2011-06-07

Evaporation of aqueous droplets of carbon nanotubes (CNTs) coated with a physisorbed layer of humic acid (HA) on a partially hydrophilic substrate induces the formation of a film of CNTs. Here, we investigate the role that the global geometry of the substrate surfaces has on the structure of the CNT film. On a flat mica or silica surface, the evaporation of a convex droplet of the CNT dispersion induces the well-known "coffee ring", while evaporation of a concave droplet (capillary meniscus) of the CNT dispersion in a wedge of two planar mica sheets or between two crossed-cylinder sheets induces a large area (>mm 2) of textured or patterned films characterized by different short- and long-range orientational and positional ordering of the CNTs. The resulting patterns appear to be determined by two competing or cooperative sedimentation mechanisms: (1) capillary forces between CNTs giving micrometer-sized filaments parallel to the boundary line of the evaporating droplet and (2) fingering instability at the boundary line of the evaporating droplet and subsequent pinning of CNTs on the surface giving micrometer-sized filaments of CNTs perpendicular to this boundary line. The interplay between substrate surface geometry and sedimentation mechanisms gives an extra control parameter for manipulating patterns of self-assembling nanoparticles at substrate surfaces. © 2011 American Chemical Society.

Formation of Sheeting Joints as a Result of Compression Parallel to Convex Surfaces, With Examples from Yosemite National Park, California

Science.gov (United States)

Martel, S. J.

2008-12-01

The formation of sheeting joints has been an outstanding problem in geology. New observations and analyses indicate that sheeting joints develop in response to a near-surface tension induced by compressive stresses parallel to a convex slope (hypothesis 1) rather than by removal of overburden by erosion, as conventionally assumed (hypothesis 2). Opening mode displacements across the joints together with the absence of mineral precipitates within the joints mean that sheeting joints open in response to a near-surface tension normal to the surface rather than a pressurized fluid. Consideration of a plot of this tensile stress as a function of depth normal to the surface reveals that a true tension must arise in the shallow subsurface if the rate of that tensile stress change with depth is positive at the surface. Static equilibrium requires this rate (derivative) to equal P22 k2 + P33 k3 - ρ g cosβ, where k2 and k3 are the principal curvatures of the surface, P22 and P33 are the respective surface- parallel normal stresses along the principal curvatures, ρ is the material density, g is gravitational acceleration, and β is the slope. This derivative will be positive and sheeting joints can open if at least one principal curvature is sufficiently convex (negative) and the surface-parallel stresses are sufficiently compressive (negative). At several sites with sheeting joints (e.g., Yosemite National Park in California), the measured topographic curvatures and the measured surface-parallel stresses of about -10 MPa combine to meet this condition. In apparent violation of hypothesis 1, sheeting joints occur locally at the bottom of Tenaya Canyon, one of the deepest glaciated, U-shaped (concave) canyons in the park. The canyon-bottom sheeting joints only occur, however, where the canyon is convex downstream, a direction that nearly coincides with direction of the most compressive stress measured in the vicinity. The most compressive stress acting along the convex

One-level modeling for diagnosing surface winds over complex terrain. II - Applicability to short-range forecasting

Science.gov (United States)

Alpert, P.; Getenio, B.; Zak-Rosenthal, R.

1988-01-01

The Alpert and Getenio (1988) modification of the Mass and Dempsey (1985) one-level sigma-surface model was used to study four synoptic events that included two winter cases (a Cyprus low and a Siberian high) and two summer cases. Results of statistical verification showed that the model is not only capable of diagnosing many details of surface mesoscale flow, but might also be useful for various applications which require operative short-range prediction of the diurnal changes of high-resolution surface flow over complex terrain, for example, in locating wildland fires, determining the dispersion of air pollutants, and predicting changes in wind energy or of surface wind for low-level air flights.

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

International Nuclear Information System (INIS)

Park, Jongho; Kim, Beomjoon

2016-01-01

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. (paper)

A statistical method to get surface level air-temperature from satellite observations of precipitable water

Digital Repository Service at National Institute of Oceanography (India)

Pankajakshan, T.; Shikauchi, A; Sugimori, Y.; Kubota, M.

-T a and precipitable water. The rms errors of the SSMI-T a , in this case are found to be reduced to 1.0°C. 1. Introduction Satellite derived surface-level meteorological parameters are considered to be a better alternative to sparse ship... Vol. 49, pp. 551 to 558. 1993 A Statistical Method to Get Surface Level Air-Temperature from Satellite Observations of Precipitable Water PANKAJAKSHAN THADATHIL*, AKIRA SHIKAUCHI, YASUHIRO SUGIMORI and MASAHISA KUBOTA School of Marine Science...

The Interior City. Infinity and Concavity in the No-Stop City(1970-1971

Directory of Open Access Journals (Sweden)

Pablo Martínez Capdevila

2013-10-01

Full Text Available AbstractIn the late 60s it had become clear how the environment technification had allowed some typologies (supermarkets, car parks, factories to reach potentially unlimited built depths becoming, therefore, independent from the outside. The No-Stop City is born from a very simple idea: to extend this technification to the totality of built reality encompassing, not only almost all functions, but ultimately, the whole city. This operation has paradoxical effects: as architecture grows, it loses most of the features that have traditionally defined it. A dissolution by hypertrophy that gives rise to an homogeneous, concave and potentially infinite space.But beyond the pure technical feasibility, there are two key influences, seemingly contradictory, that explain this endeavor for an interior and endless city: Marxism and Pop Art. The project is, in many senses, a built manifesto reflecting the militancy of the group members within the Italian Marxism. But it is also the embodiment of the group's declared interest in Pop Art, popular culture and mass society. The cross-influence of communism and consumerism explains this "quantitative utopia" in which the society and the factory, the production and consumption, would match. A city based on the centrality of consumer products and the subsequent loss of prominence of architecture, in which the urban phenomenon, while spreading endlessly over territory, ignoring its rural exteriority, dissolves the home as a sphere of privacy, ignoring its domestic interiority.A project, also in the wake of Marshall McLuhan, that illustrates like few others the conversion of the urbane into a virtually omnipresent "condition" and that still interrogates us with questions that are, on the other hand, eternal: What is a building? What is a city?Key wordsBranzi, dissolution, pop, Marxism, neo-avant-garde

Wetland Ecohydrology: stochastic description of water level fluctuations across the soil surface

Science.gov (United States)

Tamea, S.; Muneepeerakul, R.; Laio, F.; Ridolfi, L.; Rodriguez-Iturbe, I.

2009-12-01

Wetlands provide a suite of social and ecological critical functions such as being habitats of disease-carrying vectors, providing buffer zones against hurricanes, controlling sediment transport, filtering nutrients and contaminants, and a repository of great biological diversity. More recently, wetlands have also been recognized as crucial for carbon storage in the context of global climate change. Despite such importance, quantitative approaches to many aspects of wetlands are far from adequate. Therefore, improving our quantitative understanding of wetlands is necessary to our ability to maintain, manage, and restore these invaluable environments. In wetlands, hydrologic factors and ecosystem processes interplay and generate unique characteristics and a delicate balance between biotic and abiotic elements. The main hydrologic driver of wetland ecosystems is the position of the water level that, being above or below ground, determines the submergence or exposure of soil. When the water level is above the soil surface, soil saturation and lack of oxygen causes hypoxia, anaerobic functioning of microorganisms and anoxic stress in plants, that might lead to the death of non-adapted organisms. When the water level lies below the soil surface, the ecosystem becomes groundwater-dependent, and pedological and physiological aspects play their role in the soil water balance. We propose here a quantitative description of wetland ecohydrology, through a stochastic process-based water balance, driven by a marked compound Poisson noise representing rainfall events. The model includes processes such as rainfall infiltration, evapotranspiration, capillary rise, and the contribution of external water bodies, which are quantified in a simple yet realistic way. The semi-analytical steady-state probability distributions of water level spanning across the soil surface are validated with data from the Everglades (Florida, USA). The model and its results allow for a quantitative

Uniform surface-to-line integral reduction of physical optics for curved surfaces by modified edge representation with higher-order correction

Science.gov (United States)

Lyu, Pengfei; Ando, Makoto

2017-09-01

The modified edge representation is one of the equivalent edge currents approximation methods for calculating the physical optics surface radiation integrals in diffraction analysis. The Stokes' theorem is used in the derivation of the modified edge representation from the physical optics for the planar scatterer case, which implies that the surface integral is rigorously reduced into the line integral of the modified edge representation equivalent edge currents, defined in terms of the local shape of the edge. On the contrary, for curved surfaces, the results of radiation integrals depend upon the global shape of the scatterer. The physical optics surface integral consists of two components, from the inner stationary phase point and the edge. The modified edge representation is defined independently from the orientation of the actual edge, and therefore, it could be available not only at the edge but also at the arbitrary points on the scatterer except the stationary phase point where the modified edge representation equivalent edge currents becomes infinite. If stationary phase point exists inside the illuminated region, the physical optics surface integration is reduced into two kinds of the modified edge representation line integrations, along the edge and infinitesimally small integration around the inner stationary phase point, the former and the latter give the diffraction and reflection components, respectively. The accuracy of the latter has been discussed for the curved surfaces and published. This paper focuses on the errors of the former and discusses its correction. It has been numerically observed that the modified edge representation works well for the physical optics diffraction in flat and concave surfaces; errors appear especially for the observer near the reflection shadow boundary if the frequency is low for the convex scatterer. This paper gives the explicit expression of the higher-order correction for the modified edge representation.

Monitoring the variability of sea level and surface circulation with satellite altimetry

NARCIS (Netherlands)

Volkov, Denis L. "Jr"

2004-01-01

Variability in the ocean plays an important role in determining global weather and climate conditions. The advent of satellite altimetry has significantly facilitated the study of the variability of sea level and surface circulation. Satellites provide high-quality regular and nearly global

The appearance of liquid surfaces and layers in routine radiographs

International Nuclear Information System (INIS)

Nilson, A.E.; Sahlgrenska Sjukhuset, Goeteborg

1986-01-01

As has been demonstrated, the interfaces between a gas and a body fluid or a contrast medium may be visualized in the radiographic image as various kinds of boundaries, as also may interfaces between a contrast medium and a body fluid. These can provide little diagnostic information. Data of clinical value are usually derived from boundaries that represent bounding surfaces of anatomic structures touched by the roentgen rays. In the interpretation of the radiographic image it is important to recognize whether a boundary represents an anatomic structure, a liquid surface or a diffusion layer. It is a traditional view that a liquid surface is visualized by a horizontal beam as a straight horizontal boundary and that the imaged surface is then also horizontal. As has been shown in the earlier investigations and the present one, this is not always the case, for these boundaries are usually curved with an upward concavity. It is important to bear in mind that also rays departing considerably from the horizontal may still touch the liquid surface in its meniscoid. Even a vertical beam will form a boundary when touching a meniscoid. It would also appear that the simple layering phenomenon can present difficulty in interpretation. Examples of this phenomenon that illustrate particularly important situations have been presented. Ambiguity associated with the interpretation of images produced by a vertical beam may be resolved with the aid of supplementary films exposed with a horizontal beam. (orig.)

Trends in Upper-Level Cloud Cover and Surface Divergence Over the Tropical Indo-Pacific Ocean Between 1952 And 1997

Science.gov (United States)

Norris, Joel R.

2005-01-01

This study investigated the spatial pattern of linear trends in surface-observed upper-level (combined mid-level and High-level) cloud cover, precipitation, and surface divergence over the tropical Indo-Pacific Ocean during 1952-1957. Cloud values were obtained from the Extended Edited Cloud Report Archive (EECRA), precipitation values were obtained from the Hulme/Climate Research Unit Data Set, and surface divergence was alternatively calculated from wind reported Comprehensive Ocean-Atmosphere Data Set and from Smith and Reynolds Extended Reconstructed sea level pressure data.

Surface Morphology and Bending Deformation of 2024-T3 Thin Sheets with Laser Peen Forming

Directory of Open Access Journals (Sweden)

Wu Junfeng

2018-01-01

Full Text Available Laser peen forming (LPF is a pure mechanical forming method through accumulated plastic strain, which has been successfully applied in wing components. Experimental investigation has been performed to understand the effect of process parameters such as constraint conditions, sheet thickness and laser energy on surface morphology and bending deformation of 2024-T3 thin sheets of dimensions of 76 mm ×19 mm (length × width. The research results indicated that bulges on the aluminum foil were generated at the bottom surface and not generated at the topmost surface. It was different for transition value of two-way bending deformations of thin sheets after LPF with different constraint conditions. Remain flat thicknesses of thin sheets after LPF were about 1 mm ~ 2 mm for 20 J, 25 J and 30 J. Arc heights and curvatures of 3 mm thickness sheets increased with laser energy and those of 2 mm thickness sheets only made little change. It was found that convex deformation, flat, concave deformation and laser deep drawing for thin sheets with different thicknesses after LPF.

Observation of core-level binding energy shifts between (100) surface and bulk atoms of epitaxial CuInSe2

International Nuclear Information System (INIS)

Nelson, A.J.; Berry, G.; Rockett, A.

1997-01-01

Core-level and valence band photoemission from semiconductors has been shown to exhibit binding energy differences between surface atoms and bulk atoms, thus allowing one to unambiguously distinguish between the two atomic positions. Quite clearly, surface atoms experience a potential different from the bulk due to the lower coordination number - a characteristic feature of any surface is the incomplete atomic coordination. Theoretical accounts of this phenomena are well documented in the literature for III-V and II-VI semiconductors. However, surface state energies corresponding to the equilibrium geometry of (100) and (111) surfaces of Cu-based ternary chalcopyrite semiconductors have not been calculated or experimental determined. These compounds are generating great interest for optoelectronic and photovoltaic applications, and are an isoelectronic analog of the II-VI binary compound semiconductors. Surface core-level binding energy shifts depend on the surface cohesive energies, and surface cohesive energies are related to surface structure. For ternary compound semiconductor surfaces, such as CuInSe 2 , one has the possibility of variations in surface stoichiometry. Applying standard thermodynamical calculations which consider the number of individual surface atoms and their respective chemical potentials should allow one to qualitatively determine the magnitude of surface core-level shifts and, consequently, surface state energies

Development, Characterization, and Optimization of Protein Level in Date Bars Using Response Surface Methodology

Directory of Open Access Journals (Sweden)

Muhammad Nadeem

2012-01-01

Full Text Available This project was designed to produce a nourishing date bar with commercial value especially for school going children to meet their body development requirements. Protein level of date bars was optimized using response surface methodology (RSM. Economical and underutilized sources, that is, whey protein concentrate and vetch protein isolates, were explored for protein supplementation. Fourteen date bar treatments were produced using a central composite design (CCD with 2 variables and 3 levels for each variable. Date bars were then analyzed for nutritional profile. Proximate composition revealed that addition of whey protein concentrate and vetch protein isolates improved the nutritional profile of date bars. Protein level, texture, and taste were considerably improved by incorporating 6.05% whey protein concentrate and 4.35% vetch protein isolates in date bar without affecting any sensory characteristics during storage. Response surface methodology was observed as an economical and effective tool to optimize the ingredient level and to discriminate the interactive effects of independent variables.

GHRSST Level 4 K10_SST Global 1 meter Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Naval...

GHRSST Level 4 ODYSSEA Eastern Central Pacific Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

GHRSST Level 4 ODYSSEA North-Western Europe Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

High performance reliability fuel pellet

International Nuclear Information System (INIS)

Beuchel, P.H.; Lee, Y.C.

1989-01-01

A fuel pellet for a nuclear reactor fuel rod is described comprising: a substantially cylindrical central section; a convex first end section smoothly joined to one axial end of the central section at a first junction, the first junction approximating a smooth and continuous curved surface; a concave second end section joined to the central section at a second junction, the second junction approximating a smooth and continuous curved surface, wherein the curvature of the concave second end section is conformed to the curvature of the convex first end section

GHRSST Level 4 CMC0.1deg Global Foundation Sea Surface Temperature Analysis (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature (SST) analysis produced daily on an operational basis at the Canadian...

GHRSST Level 4 CMC0.2deg Global Foundation Sea Surface Temperature Analysis (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature (SST) analysis produced daily on an operational basis at the Canadian...

Experimental investigations of sensor-based surface following performed by a mobile manipulator

Energy Technology Data Exchange (ETDEWEB)

Reister, D.B.; Unseren, M.A.; Baker, J.E.; Pin, F.G.

1994-10-01

We discuss a series of surface following experiments using a range finder mounted on the end of an arm that is mounted on a vehicle. The goal is to keep the range finder at a fixed distance from an unknown surface and to keep the orientation of the range finder perpendicular to the surface. During the experiments, the vehicle moves along a predefined trajectory while planning software determines the position and orientation of the arm. To keep the range finder perpendicular to the surface, the planning software calculates the surface normal for the unknown surface. We assume that the unknown surface is a cylinder (the surface depends on x and y but does not depend on z). To calculate the surface normal, the planning software must calculate the locations (x,y) of points on the surface in world coordinates. The calculation requires data on the position and orientation of the vehicle, the position and orientation of the arm, and the distance from the range finder to the surface. We discuss four series of experiments. During the first series of experiments, the calculated surface normal values had large high frequency random variations. A filter was used to produce an average value for the surface normal and we limited the rate of change in the yaw angle target for the arm. We performed the experiment for a variety of concave and convex surfaces. While the experiments were qualitative successes, the measured distance to the surface was significantly different than the target. The distance errors were systematic, low frequency, and had magnitudes up to 25 mm. During the second series of experiments, we reduced the variations in the calculated surface normal values. While reviewing the data collected while following the surface of a barrel, we found that the radius of the calculated surface was significantly different than the measured radius of the barrel.

An optomechatronic curvature measurement array based on fiber Bragg gratings

International Nuclear Information System (INIS)

Chang, Hsing-Cheng; Lin, Shyan-Lung; Hung, San-Shan; Chang, I-Nan; Chen, Ya-Hui; Lin, Jung-Chih; Liu, Wen-Fung

2014-01-01

This study investigated an optomechatronic array-integrated signal processing module and a human–machine interface based on fiber Bragg grating sensing elements embedded in an elastic support matrix that involves using a self-located electromagnetic mechanism for curvature sensing and solid contour reconstruction. Using bilinear interpolation and average calculation methods, the smooth and accurate surface contours of convex and concave lenses are reconstructed in real-time. The elastic supporting optical sensing array is self-balanced to reduce operational errors. Compared with our previous single-head sensor, the sensitivity of the proposed array is improved by more than 15%. In the curvature range from −20.15 to +27.09 m −1 , the sensitivities are 3.53 pm m for the convex measurement and 2.15 pm m for the concave measurement with an error rate below 8.89%. The curvature resolutions are 0.283 and 0.465 m −1 for convex and concave lenses, respectively. This array could be applied in the curvature measurement of solar collectors to monitor energy conversion efficiency or could be used to monitor the wafer-level thin-film fabrication process. (paper)

High Compressive Stresses Near the Surface of the Sierra Nevada, California

Science.gov (United States)

Martel, S. J.; Logan, J. M.; Stock, G. M.

2012-12-01

Observations and stress measurements in granitic rocks of the Sierra Nevada, California reveal strong compressive stresses parallel to the surface of the range at shallow depths. New overcoring measurements show high compressive stresses at three locations along an east-west transect through Yosemite National Park. At the westernmost site (west end of Tenaya Lake), the mean compressive stress is 1.9. At the middle site (north shore of Tenaya Lake) the mean compressive stress is 6.8 MPa. At the easternmost site (south side of Lembert Dome) the mean compressive stress is 3.0 MPa. The trend of the most compressive stress at these sites is within ~30° of the strike of the local topographic surface. Previously published hydraulic fracturing measurements by others elsewhere in the Sierra Nevada indicate surface-parallel compressive stresses of several MPa within several tens of meters of the surface, with the stress magnitudes generally diminishing to the west. Both the new and the previously published compressive stress magnitudes are consistent with the presence of sheeting joints (i.e., "exfoliation joints") in the Sierra Nevada, which require lateral compressive stresses of several MPa to form. These fractures are widespread: they are distributed in granitic rocks from the north end of the range to its southern tip and across the width of the range. Uplift along the normal faults of the eastern escarpment, recently measured by others at ~1-2 mm/yr, probably contributes to these stresses substantially. Geodetic surveys reveal that normal faulting flexes a range concave upwards in response to fault slip, and this flexure is predicted by elastic dislocation models. The topographic relief of the eastern escarpment of the Sierra Nevada is 2-4 km, and since alluvial fill generally buries the bedrock east of the faults, the offset of granitic rocks is at least that much. Compressive stresses of several MPa are predicted by elastic dislocation models of the range front

Preferences of lame cows for type of surface and level of social contact in hospital pens

DEFF Research Database (Denmark)

Jensen, Margit Bak; Herskin, Mette S; Thomsen, Peter T.

2015-01-01

To investigate preferences of lame cows for flooring and level of social contact, 37 lame, lactating dairy cows (diagnosed with sole ulcer or white line disease) were housed individually for 6 d in experimental hospital pens, where they could choose between 2 equally sized areas (6m × 4.5m......) with either deep-bedded sand or a rubber surface. On both surfaces, cows could choose between 2 equally sized areas either near or away from heifers in a neighboring group pen. Cows spent more time lying on the deep-bedded sand than on the rubber surface (870 vs. 71min/d), whereas they spent less time upright...... (standing or walking) on the sand than on the rubber surface (180 vs. 319min/d). In addition, cows spent less time self-grooming on the sand than on the rubber surface (2.2 vs. 4.7% of time spent upright). With regard to level of social contact, cows spent more time near the neighboring heifers than away...

Microbiological levels of randomly selected food contact surfaces in hotels located in Spain during 2007-2009.

Science.gov (United States)

Doménech-Sánchez, Antonio; Laso, Elena; Pérez, María José; Berrocal, Clara Isabel

2011-09-01

The aim of this study was to survey the microbial levels of food contact surfaces in hotels. Microbiological levels of 4611 surfaces (chopping machines, kitchenware, knives, worktops, and cutting boards) from 280 different facilities in Spain were determined in a 3-year period. The contact-plate technique was used throughout the survey. Overall, the mean of the log of total aerobic count cm(-2) was 0.62, better than those reported for child-care and assisted living facilities. Significant differences were detected among different types of surfaces, time of sampling, season, and year. The majority (74%) of food contact surfaces sampled in Spanish hotels was within the recommended standard of <1.3 log CFU cm(-2), and differences depend on several factors. Our results set a representative picture of the actual situation in our resorts and establish the basis for the development of educational programs to improve food handlers' knowledge of foodborne diseases and their transmission via food contact surfaces.

Patch layout generation by detecting feature networks

KAUST Repository

Cao, Yuanhao

2015-02-01

The patch layout of 3D surfaces reveals the high-level geometric and topological structures. In this paper, we study the patch layout computation by detecting and enclosing feature loops on surfaces. We present a hybrid framework which combines several key ingredients, including feature detection, feature filtering, feature curve extension, patch subdivision and boundary smoothing. Our framework is able to compute patch layouts through concave features as previous approaches, but also able to generate nice layouts through smoothing regions. We demonstrate the effectiveness of our framework by comparing with the state-of-the-art methods.

Statistical analysis of global surface temperature and sea level using cointegration methods

DEFF Research Database (Denmark)

Schmidt, Torben; Johansen, Søren; Thejll, Peter

2012-01-01

Global sea levels are rising which is widely understood as a consequence of thermal expansion and melting of glaciers and land-based ice caps. Due to the lack of representation of ice-sheet dynamics in present-day physically-based climate models being unable to simulate observed sea level trends......, semi-empirical models have been applied as an alternative for projecting of future sea levels. There is in this, however, potential pitfalls due to the trending nature of the time series. We apply a statistical method called cointegration analysis to observed global sea level and land-ocean surface air...... temperature, capable of handling such peculiarities. We find a relationship between sea level and temperature and find that temperature causally depends on the sea level, which can be understood as a consequence of the large heat capacity of the ocean. We further find that the warming episode in the 1940s...

Cavity-ligand binding in a simple two-dimensional water model

Directory of Open Access Journals (Sweden)

G. Mazovec

2016-02-01

Full Text Available By means of Monte Carlo computer simulations in the isothermal-isobaric ensemble, we investigated the interaction of a hydrophobic ligand with the hydrophobic surfaces of various curvatures (planar, convex and concave. A simple two-dimensional model of water, hydrophobic ligand and surface was used. Hydration/dehidration phenomena concerning water molecules confined close to the molecular surface were investigated. A notable dewetting of the hydrophobic surfaces was observed together with the reorientation of the water molecules close to the surface. The hydrogen bonding network was formed to accommodate cavities next to the surfaces as well as beyond the first hydration shell. The effects were most strongly pronounced in the case of concave surfaces having large curvature. This simplified model can be further used to evaluate the thermodynamic fingerprint of the docking of hydrophobic ligands.

Debris thickness patterns on debris-covered glaciers

Science.gov (United States)

Anderson, Leif S.; Anderson, Robert S.

2018-06-01

Many debris-covered glaciers have broadly similar debris thickness patterns: surface debris thickens and tends to transition from convex- to concave-up-down glacier. We explain this pattern using theory (analytical and numerical models) paired with empirical observations. Down glacier debris thickening results from the conveyor-belt-like nature of the glacier surface in the ablation zone (debris can typically only be added but not removed) and from the inevitable decline in ice surface velocity toward the terminus. Down-glacier thickening of debris leads to the reduction of sub-debris melt and debris emergence toward the terminus. Convex-up debris thickness patterns occur near the up-glacier end of debris covers where debris emergence dominates (ablation controlled). Concave-up debris thickness patterns occur toward glacier termini where declining surface velocities dominate (velocity controlled). A convex-concave debris thickness profile inevitably results from the transition between ablation-control and velocity-control down-glacier. Debris thickness patterns deviating from this longitudinal shape are most likely caused by changes in hillslope debris supply through time. By establishing this expected debris thickness pattern, the effects of climate change on debris cover can be better identified.

Friction welding method

International Nuclear Information System (INIS)

Ishida, Ryuichi; Hatanaka, Tatsuo.

1969-01-01

A friction welding method for forming a lattice-shaped base and tie plate supporter for fuel elements is disclosed in which a plate formed with a concavity along its edge is pressure welded to a rotating member such as a boss by longitudinally contacting the projecting surfaces remaining on either side of the concavity with the rotating member during the high speed rotation thereof in the presence of an inert gas. Since only the two projecting surfaces of the plate are fused by friction to the rotary member, heat expansion is absorbed by the concavity to prevent distortion; moreover, a two point contact surface assures a stable fitting and promotes the construction of a rigid lattice in which a number of the abovementioned plates are friction welded between rotating members to form any desired complex arrangement. The inert has serves to protect the material quality of the contacting surfaces from air during the welding step. The present invention thus provides a method in which even Zircaloy may be friction welded in place of casting stainless steel in the construction of supporting lattices to thereby enhance neutron economy. (K. J. Owens)

Atomic-level spatial distributions of dopants on silicon surfaces: toward a microscopic understanding of surface chemical reactivity

Science.gov (United States)

Hamers, Robert J.; Wang, Yajun; Shan, Jun

1996-11-01

We have investigated the interaction of phosphine (PH 3) and diborane (B 2H 6) with the Si(001) surface using scanning tunneling microscopy, infrared spectroscopy, and ab initio molecular orbital calculations. Experiment and theory show that the formation of PSi heterodimers is energetically favorable compared with formation of PP dimers. The stability of the heterodimers arises from a large strain energy associated with formation of PP dimers. At moderate P coverages, the formation of PSi heterodimers leaves the surface with few locations where there are two adjacent reactive sites. This in turn modifies the chemical reactivity toward species such as PH 3, which require only one site to adsorb but require two adjacent sites to dissociate. Boron on Si(001) strongly segregates into localized regions of high boron concentration, separated by large regions of clean Si. This leads to a spatially-modulated chemical reactivity which during subsequent growth by chemical vapor deposition (CVD) leads to formation of a rough surface. The implications of the atomic-level spatial distribution of dopants on the rates and mechanisms of CVD growth processes are discussed.

Observation of core-level binding energy shifts between (100) surface and bulk atoms of epitaxial CuInSe{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Nelson, A.J. [Colorado School of Mines, Golden, CO (United States); Berry, G.; Rockett, A. [Univ. of Illinois, Urbana-Champaign, IL (United States)] [and others

1997-04-01

Core-level and valence band photoemission from semiconductors has been shown to exhibit binding energy differences between surface atoms and bulk atoms, thus allowing one to unambiguously distinguish between the two atomic positions. Quite clearly, surface atoms experience a potential different from the bulk due to the lower coordination number - a characteristic feature of any surface is the incomplete atomic coordination. Theoretical accounts of this phenomena are well documented in the literature for III-V and II-VI semiconductors. However, surface state energies corresponding to the equilibrium geometry of (100) and (111) surfaces of Cu-based ternary chalcopyrite semiconductors have not been calculated or experimental determined. These compounds are generating great interest for optoelectronic and photovoltaic applications, and are an isoelectronic analog of the II-VI binary compound semiconductors. Surface core-level binding energy shifts depend on the surface cohesive energies, and surface cohesive energies are related to surface structure. For ternary compound semiconductor surfaces, such as CuInSe{sub 2}, one has the possibility of variations in surface stoichiometry. Applying standard thermodynamical calculations which consider the number of individual surface atoms and their respective chemical potentials should allow one to qualitatively determine the magnitude of surface core-level shifts and, consequently, surface state energies.

Unraveling origins of the heterogeneous curvature dependence of polypeptide interactions with carbon nanostructures.

Science.gov (United States)

Jana, Asis K; Tiwari, Mrityunjay K; Vanka, Kumar; Sengupta, Neelanjana

2016-02-17

Emerging nanotechnology has rapidly broadened interfacial prospects of biological molecules with carbon nanomaterials (CNs). A prerequisite for effectively harnessing such hybrid materials is a multi-faceted understanding of their complex interfacial interactions as functions of the physico-chemical characteristics and the surface topography of the individual components. In this article, we address the origins of the curvature dependence of polypeptide adsorption on CN surfaces (CNSs), a phenomenon bearing an acute influence upon the behavior and activity of CN-protein conjugates. Our benchmark molecular dynamics (MD) simulations with the amphiphilic full-length amyloid beta (Aβ) peptide demonstrate that protein adsorption is strongest on the concave (inner) CN surface, weakest on the convex (outer) surface, and intermediary on the planar surface, in agreement with recent experimental reports. The curvature effects, however, are found to manifest non-uniformly between the amino acid subtypes. To understand the underlying interplay of the chemical nature of the amino acids and surface topography of the CNs, we performed high-level quantum chemical (QM) calculations with amino acid analogs (AAA) representing their five prominent classes, and convex, concave and planar CN fragments. Molecular electrostatic potential maps reveal pronounced curvature dependence in the mixing of electron densities, and a resulting variance in the stabilization of the non-covalently bound molecular complexes. Interestingly, our study revealed that the interaction trends of the high-level QM calculations were captured well by the empirical force field. The findings in this study have important bearing upon the design of carbon based bio-nanomaterials, and additionally, provide valuable insights into the accuracy of various computational techniques for probing non-bonded interfacial interactions.

A Study of Electrostatic Charge on Insulating Film by Electrostatic Force Microscopy

International Nuclear Information System (INIS)

Kikunaga, K; Toosaka, K; Kamohara, T; Sakai, K; Nonaka, K

2011-01-01

Electrostatic charge properties on polypropylene film have been characterized by atomic force microscopy and electrostatic force microscopy. The measurements have been carried out after the polypropylene film was electrified by contact and separation process in an atmosphere of controlled humidity. The negative and positive charge in concave surface has been observed. The correlation between concave surface and charge position suggests that the electrostatic charges could be caused by localized contact. On the other hand, positive charge on a flat surface has been observed. The absence of a relationship between surface profile and charge position suggests that the electrostatic charge should be caused by discharge during the separation process. The spatial migration of other positive charges through surface roughness has been observed. The results suggest that there could be some electron traps on the surface roughness and some potentials on the polypropylene film.

GHRSST Level 4 REMO_OI_SST_5km Regional Foundation Sea Surface Temperature Analysis (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature (SST) analysis produced daily on an operational basis by the...

Alkyl-terminated Si(111) surfaces: A high-resolution, core level photoelectron spectroscopy study

Energy Technology Data Exchange (ETDEWEB)

Terry, J.; Linford, M.R.; Wigren, C.; Cao, R.; Pianetta, P.; Chidsey, C.E. [Stanford University, Stanford, California 94309 (United States)

1999-01-01

The bonding of alkyl monolayers to Si(111) surfaces has been studied with high-resolution core level photoelectron spectroscopy (PES). Two very different wet-chemical methods have been used to prepare the alkyl monolayers: (i) Olefin insertion into the H{endash}Si bond of the H{endash}Si(111) surface, and (ii) replacement of Cl on the Cl{endash}Si(111) surface by an alkyl group from an alkyllithium reagent. In both cases, PES has revealed a C 1s component shifted to lower binding energy and a Si 2p component shifted to higher binding energy. Both components are attributed to the presence of a C{endash}Si bond at the interface. Along with photoelectron diffraction data [Appl. Phys. Lett. {bold 71}, 1056, (1997)], these data are used to show that these two synthetic methods can be used to functionalize the Si(111) surface. {copyright} {ital 1999 American Institute of Physics.}

Polarization-induced renormalization of molecular levels at metallic and semiconducting surfaces

DEFF Research Database (Denmark)

García Lastra, Juan Maria; Rostgaard, Carsten; Rubio, A.

2009-01-01

On the basis of first-principles G0W0 calculations we systematically study how the electronic levels of a benzene molecule are renormalized by substrate polarization when physisorbed on different metallic and semiconducting surfaces. The polarization-induced reduction in the energy gap between oc...... find that error cancellations lead to remarkably good agreement between the G0W0 and Kohn-Sham energies for the occupied orbitals of the adsorbed molecule....

Molecular-level removal of proteinaceous contamination from model surfaces and biomedical device materials by air plasma treatment.

Science.gov (United States)

Banerjee, K K; Kumar, S; Bremmell, K E; Griesser, H J

2010-11-01

Established methods for cleaning and sterilising biomedical devices may achieve removal of bioburden only at the macroscopic level while leaving behind molecular levels of contamination (mainly proteinaceous). This is of particular concern if the residue might contain prions. We investigated at the molecular level the removal of model and real-life proteinaceous contamination from model and practical surfaces by air plasma (ionised air) treatment. The surface-sensitive technique of X-ray photoelectron spectroscopy (XPS) was used to assess the removal of proteinaceous contamination, with the nitrogen (N1s) photoelectron signal as its marker. Model proteinaceous contamination (bovine serum albumin) adsorbed on to a model surface (silicon wafer) and the residual proteinaceous contamination resulting from incubating surgical stainless steel (a practical biomaterial) in whole human blood exhibited strong N1s signals [16.8 and 18.5 atomic percent (at.%), respectively] after thorough washing. After 5min air plasma treatment, XPS detected no nitrogen on the sample surfaces, indicating complete removal of proteinaceous contamination, down to the estimated XPS detection limit 10ng/cm(2). Applying the same plasma treatment, the 7.7at.% nitrogen observed on a clinically cleaned dental bur was reduced to a level reflective of new, as-received burs. Contact angle measurements and atomic force microscopy also indicated complete molecular-level removal of the proteinaceous contamination upon air plasma treatment. This study demonstrates the effectiveness of air plasma treatment for removing proteinaceous contamination from both model and practical surfaces and offers a method for ensuring that no molecular residual contamination such as prions is transferred upon re-use of surgical and dental instruments. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Two-Level Micro-to-Nanoscale Hierarchical TiO2 Nanolayers on Titanium Surface

Directory of Open Access Journals (Sweden)

Elena G. Zemtsova

2016-12-01

Full Text Available Joint replacement is being actively developed within modern orthopedics. One novel material providing fast implantation is bioactive coatings. The synthesis of targeted nanocoatings on metallic nanotitanium surface is reported in this paper. TiO2-based micro- and nanocoatings were produced by sol-gel synthesis using dip-coating technology with subsequent fast (shock drying in hot plate mode at 400 °C. As a result of shock drying, the two-level hierarchical TiO2 nanolayer on the nanotitanium was obtained. This two-level hierarchy includes nanorelief of porous xerogel and microrelief of the micron-sized “defect” network (a crack network. The thickness of TiO2 nanolayers was controlled by repeating dip-coating process the necessary number of times after the first layer deposition. The state of the MS3T3-E1 osteoblast cell line (young cells that form bone tissue on the two-level hierarchical surface has been studied. Particularly, adhesion character, adhesion time and morphology have been studied. The reported results may serve the starting point for the development of novel bioactive coatings for bone and teeth implants.

GHRSST Level 4 MW_IR_OI Global Foundation Sea Surface Temperature analysis (GDS versions 1 and 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) global Level 4 sea surface temperature analysis produced daily on a 0.81 degree grid at Remote Sensing...

Statistical analysis of global surface air temperature and sea level using cointegration methods

DEFF Research Database (Denmark)

Schmith, Torben; Johansen, Søren; Thejll, Peter

Global sea levels are rising which is widely understood as a consequence of thermal expansion and melting of glaciers and land-based ice caps. Due to physically-based models being unable to simulate observed sea level trends, semi-empirical models have been applied as an alternative for projecting...... of future sea levels. There is in this, however, potential pitfalls due to the trending nature of the time series. We apply a statistical method called cointegration analysis to observed global sea level and surface air temperature, capable of handling such peculiarities. We find a relationship between sea...... level and temperature and find that temperature causally depends on the sea level, which can be understood as a consequence of the large heat capacity of the ocean. We further find that the warming episode in the 1940s is exceptional in the sense that sea level and warming deviates from the expected...

The visual system prioritizes locations near corners of surfaces (not just locations near a corner).

Science.gov (United States)

Bertamini, Marco; Helmy, Mai; Bates, Daniel

2013-11-01

When a new visual object appears, attention is directed toward it. However, some locations along the outline of the new object may receive more resources, perhaps as a consequence of their relative importance in describing its shape. Evidence suggests that corners receive enhanced processing, relative to the straight edges of an outline (corner enhancement effect). Using a technique similar to that in an original study in which observers had to respond to a probe presented near a contour (Cole et al. in Journal of Experimental Psychology: Human Perception and Performance 27:1356-1368, 2001), we confirmed this effect. When figure-ground relations were manipulated using shaded surfaces (Exps. 1 and 2) and stereograms (Exps. 3 and 4), two novel aspects of the phenomenon emerged: We found no difference between corners perceived as being convex or concave, and we found that the enhancement was stronger when the probe was perceived as being a feature of the surface that the corner belonged to. Therefore, the enhancement is not based on spatial aspects of the regions in the image, but critically depends on figure-ground stratification, supporting the link between the prioritization of corners and the representation of surface layout.

Physical basis for river segmentation from water surface observables

Science.gov (United States)

Samine Montazem, A.; Garambois, P. A.; Calmant, S.; Moreira, D. M.; Monnier, J.; Biancamaria, S.

2017-12-01

With the advent of satellite missions such as SWOT we will have access to high resolution estimates of the elevation, slope and width of the free surface. A segmentation strategy is required in order to sub-sample the data set into reach master points for further hydraulic analyzes and inverse modelling. The question that arises is : what will be the best node repartition strategy that preserves hydraulic properties of river flow? The concept of hydraulic visibility introduced by Garambois et al. (2016) is investigated in order to highlight and characterize the spatio-temporal variations of water surface slope and curvature for different flow regimes and reach geometries. We show that free surface curvature is a powerful proxy for characterizing the hydraulic behavior of a reach since concavity of water surface is driven by variations in channel geometry that impacts the hydraulic properties of the flow. We evaluated the performance of three segmentation strategies by means of a well documented case, that of the Garonne river in France. We conclude that local extrema of free surface curvature appear as the best candidate for locating the segment boundaries for an optimal hydraulic representation of the segmented river. We show that for a given river different segmentation scales are possible: a fine-scale segmentation which is driven by fine-scale hydraulic to large-scale segmentation driven by large-scale geomorphology. The segmentation technique is then applied to high resolution GPS profiles of free surface elevation collected on the Negro river basin, a major contributor of the Amazon river. We propose two segmentations: a low-resolution one that can be used for basin hydrology and a higher resolution one better suited for local hydrodynamic studies.

The role of surface and subsurface processes in keeping pace with sea level rise in intertidal wetlands of Moreton Bay, Queensland, Australia

Science.gov (United States)

Lovelock, Catherine E.; Bennion, Vicki; Grinham, Alistair; Cahoon, Donald R.

2011-01-01

Increases in the elevation of the soil surfaces of mangroves and salt marshes are key to the maintenance of these habitats with accelerating sea level rise. Understanding the processes that give rise to increases in soil surface elevation provides science for management of landscapes for sustainable coastal wetlands. Here, we tested whether the soil surface elevation of mangroves and salt marshes in Moreton Bay is keeping up with local rates of sea level rise (2.358 mm y-1) and whether accretion on the soil surface was the most important process for keeping up with sea level rise. We found variability in surface elevation gains, with sandy areas in the eastern bay having the highest surface elevation gains in both mangrove and salt marsh (5.9 and 1.9 mm y-1) whereas in the muddier western bay rates of surface elevation gain were lower (1.4 and -0.3 mm y-1 in mangrove and salt marsh, respectively). Both sides of the bay had similar rates of surface accretion (~7–9 mm y-1 in the mangrove and 1–3 mm y-1 in the salt marsh), but mangrove soils in the western bay were subsiding at a rate of approximately 8 mm y-1, possibly due to compaction of organic sediments. Over the study surface elevation increments were sensitive to position in the intertidal zone (higher when lower in the intertidal) and also to variation in mean sea level (higher at high sea level). Although surface accretion was the most important process for keeping up with sea level rise in the eastern bay, subsidence largely negated gains made through surface accretion in the western bay indicating a high vulnerability to sea level rise in these forests.

Detecting local ligand-binding site similarity in nonhomologous proteins by surface patch comparison.

Science.gov (United States)

Sael, Lee; Kihara, Daisuke

2012-04-01

Functional elucidation of proteins is one of the essential tasks in biology. Function of a protein, specifically, small ligand molecules that bind to a protein, can be predicted by finding similar local surface regions in binding sites of known proteins. Here, we developed an alignment free local surface comparison method for predicting a ligand molecule which binds to a query protein. The algorithm, named Patch-Surfer, represents a binding pocket as a combination of segmented surface patches, each of which is characterized by its geometrical shape, the electrostatic potential, the hydrophobicity, and the concaveness. Representing a pocket by a set of patches is effective to absorb difference of global pocket shape while capturing local similarity of pockets. The shape and the physicochemical properties of surface patches are represented using the 3D Zernike descriptor, which is a series expansion of mathematical 3D function. Two pockets are compared using a modified weighted bipartite matching algorithm, which matches similar patches from the two pockets. Patch-Surfer was benchmarked on three datasets, which consist in total of 390 proteins that bind to one of 21 ligands. Patch-Surfer showed superior performance to existing methods including a global pocket comparison method, Pocket-Surfer, which we have previously introduced. Particularly, as intended, the accuracy showed large improvement for flexible ligand molecules, which bind to pockets in different conformations. Copyright © 2011 Wiley Periodicals, Inc.

Robust space-time extraction of ventricular surface evolution using multiphase level sets

Science.gov (United States)

Drapaca, Corina S.; Cardenas, Valerie; Studholme, Colin

2004-05-01

This paper focuses on the problem of accurately extracting the CSF-tissue boundary, particularly around the ventricular surface, from serial structural MRI of the brain acquired in imaging studies of aging and dementia. This is a challenging problem because of the common occurrence of peri-ventricular lesions which locally alter the appearance of white matter. We examine a level set approach which evolves a four dimensional description of the ventricular surface over time. This has the advantage of allowing constraints on the contour in the temporal dimension, improving the consistency of the extracted object over time. We follow the approach proposed by Chan and Vese which is based on the Mumford and Shah model and implemented using the Osher and Sethian level set method. We have extended this to the 4 dimensional case to propagate a 4D contour toward the tissue boundaries through the evolution of a 5D implicit function. For convergence we use region-based information provided by the image rather than the gradient of the image. This is adapted to allow intensity contrast changes between time frames in the MRI sequence. Results on time sequences of 3D brain MR images are presented and discussed.

Semi-analytical computation of the acoustic field of a segment of a cylindrically concave transducer in lossless and attenuating media.

Science.gov (United States)

Karbeyaz, Başak Ulker; Miller, Eric L; Cleveland, Robin O

2007-02-01

Conventional ultrasound transducers used for medical diagnosis generally consist of linearly aligned rectangular apertures with elements that are focused in one plane. While traditional beamforming is easily accomplished with such transducers, the development of quantitative, physics-based imaging methods, such as tomography, requires an accurate, and computationally efficient, model of the field radiated by the transducer. The field can be expressed in terms of the Helmholtz-Kirchhoff integral; however, its direct numerical evaluation is a computationally intensive task. Here, a fast semianalytical method based on Stepanishen's spatial impulse response formulation [J. Acoust. Soc. Am. 49, 1627-1638 (1971)] is developed to compute the acoustic field of a rectangular element of cylindrically concave transducers in a homogeneous medium. The pressure field, for, lossless and attenuating media, is expressed as a superposition of Bessel functions, which can be evaluated rapidly. In particular, the coefficients of the Bessel series are frequency independent and need only be evaluated once for a given transducer. A speed up of two orders of magnitude is obtained compared to an optimized direct numerical integration. The numerical results are compared with Field II and the Fresnel approximation.

Levels of Cd, Hg and Zn in some surface waters from the Eastern ...

African Journals Online (AJOL)

Total trace metals levels - Cd, Hg and Zn, which may affect human health and the "health" of the aquatic ecosystem, were determined in the Umtata, Buffalo, Keiskamma and Tyume Rivers and in the Sandile and Umtata Dams. These elements were also determined in sediment samples from some of these surface waters.

Time lag between the tropopause height and the levels of 7Be concentration in near surface air

Science.gov (United States)

Ioannidou, A.; Vasileiadis, A.; Melas, D.

2012-04-01

The concentration of 7Be at near surface air has been determined over 2009, a year of a deep solar minimum, in the region of Thessaloniki, Greece at 40°62' N, 22°95'E. In geomagnetic latitudes over 40° N, the elevation of the tropopause during the warm summer months and the vertical exchange of air masses within the troposphere cause greater mixture of the air masses resulting in higher concentration levels for 7Be in surface air. The positive correlation between the monthly activity concentration of 7Be and the tropopause height (0.94, p rate of vertical transport within the troposphere, especially during warmer summer months, has as a result the descent to surface of air masses enriched in 7Be. However, the 7Be concentration levels in near surface air are not expected to respond immediately to the change of elevation of the tropopause. It was found that there's a time lag of ~ 3 days between the change in the daily surface concentrations of 7Be the change in the elevation of the tropopause.

Dirty snowball - now is too primitive for a scientific description of comets

Science.gov (United States)

Kochemasov, G.

Success of the "Deep Space 1" scientists which acquired excellent pictures of comet Borrelli, brings comets into the family of small celestial bodies with common regularities of shaping. Often attracted accidental impact process never can explain constantly repeated shapes of small bodies. Understanding their shaping is important in view of coming missions to small bodies. "Orbits make structures". This fundamental notion is unfolded into 4 theorems of planetary tectonics [1]: 1. Celestial bodies are dichotomic; 2. -" - are sectoral; 3. -"- are granular; 4. Angular momenta of different level blocks tend to be equal. All these general rules of shaping and structurization are a consequence of interferences of warping any body standing planetary waves due to inertia forces acting in any moving in non-circular orbit body. Dichotomy is the most global tectonic feature due to the fundamental waves (wave 1). It is typical to all planetary spheres. In Earth it is in the core, mantle, crust, atmosphere. At Venus it is very pronounced in the crust and in atmosphere: lying Y-feature and inverse C-feature in the cloud layer. Coherent martian lithosphere- atmosphere dichotomies are well known. In small bodies the dichotomy is specifically pronounced as ubiquitous convexo -concave shape. Most detailed studied at Eros this shape was also observed at comet Halley and recently at Borrelli. Borrelli's convex extended half is strongly jagged (not easy to find a place for landing!), the contracted concave half spits out tremendous tail. Surface areas around the tail outlets are whitish and lighter than surroundings. It seems that the gas-dust material squeezed out of interiors not only disappears in space but leaves traces on the concave surface. The concave hemisphere has shorter radius than the convex one and tends to compensate loosing angular momentum by denser material extracted from interiors (Theorem 4 [1];compare with the basaltic Pacific hemisphere opposed by the granitic

Near-surface storage facilities for vitrified high-level wastes

International Nuclear Information System (INIS)

Kondrat'ev, A.N.; Kulichenko, V.V.; Kryukov, I.I.; Krylova, N.V.; Paramoshkin, V.I.; Strakhov, M.V.

1980-01-01

Concurrently with the development of methods for solidifying liquid radioactive wastes, reliable and safe methods for the storage and disposal of solidified wastes are being devised in the USSR and other countries. One of the main factors affecting the choice of storage conditions for solidified wastes originating from the vitrification of high-level liquid wastes from fuel reprocessing plants is the problem of removing the heat produced by radioactive decay. In order to prevent the temperature of solidified wastes from exceeding the maximum permissible level for the material concerned, it is necessary to limit either the capacity of waste containers or the specific heat release of the wastes themselves. In order that disposal of high-level wastes in geological formations should be reliable and economic, solidified wastes undergo interim storage in near-surface storage facilities with engineered cooling systems. The paper demonstrates the relative influences of specific heat release, of the maximum permissible storage temperature for vitrified wastes and of the methods chosen for cooling wastes in order for the dimensions of waste containers to be reduced to the extent required. The effect of concentrating wastes to a given level in the vitrification process on the cost of storage in different types of storage facility is also examined. Calculations were performed for the amount of vitrified wastes produced by a reprocessing plant with a capacity of five tonnes of uranium per 24 hours. Fuel elements from reactors of the water-cooled, water-moderated type are sent for reprocessing after having been held for about two years. The dimensions of the storage facility are calculated on the assumption that it will take five years to fill

GHRSST Level 4 MUR Global Foundation Sea Surface Temperature Analysis (v4.1) (GDS versions 1 and 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced as a retrospective dataset (four day latency) and...

Travelling-wave similarity solutions for a steadily translating slender dry patch in a thin fluid film

KAUST Repository

Yatim, Y. M.

2013-01-01

A novel family of three-dimensional travelling-wave similarity solutions describing a steadily translating slender dry patch in an infinitely wide thin fluid film on an inclined planar substrate when surface-tension effects are negligible is obtained, the flow being driven by gravity and/or a prescribed constant shear stress on the free surface of the film. For both driving mechanisms, the dry patch has a parabolic shape (which may be concave up or concave down the substrate), and the film thickness increases monotonically away from the contact lines to its uniform far-field value. The two most practically important cases of purely gravity-driven flow and of purely surface-shear-stress-driven flow are analysed separately. © 2013 AIP Publishing LLC.

3D morphometry of red blood cells by digital holography.

Science.gov (United States)

Memmolo, Pasquale; Miccio, Lisa; Merola, Francesco; Gennari, Oriella; Netti, Paolo Antonio; Ferraro, Pietro

2014-12-01

Three dimensional (3D) morphometric analysis of flowing and not-adherent cells is an important aspect for diagnostic purposes. However, diagnostics tools need to be quantitative, label-free and, as much as possible, accurate. Recently, a simple holographic approach, based on shape from silhouette algorithm, has been demonstrated for accurate calculation of cells biovolume and displaying their 3D shapes. Such approach has been adopted in combination with holographic optical tweezers and successfully applied to cells with convex shape. Nevertheless, unfortunately, the method fails in case of specimen with concave surfaces. Here, we propose an effective approach to achieve correct 3D shape measurement that can be extended in case of cells having concave surfaces, thus overcoming the limit of the previous technique. We prove the new procedure for healthy red blood cells (RBCs) (i.e., discocytes) having a concave surface in their central region. Comparative analysis of experimental results with a theoretical 3D geometrical model of RBC is discussed in order to evaluate accuracy of the proposed approach. Finally, we show that the method can be also useful to classify, in terms of morphology, different varieties of RBCs. © 2014 International Society for Advancement of Cytometry.

What Are Normal Metal Ion Levels After Total Hip Arthroplasty? A Serologic Analysis of Four Bearing Surfaces.

Science.gov (United States)

Barlow, Brian T; Ortiz, Philippe A; Boles, John W; Lee, Yuo-Yu; Padgett, Douglas E; Westrich, Geoffrey H

2017-05-01

The recent experiences with adverse local tissue reactions have highlighted the need to establish what are normal serum levels of cobalt (Co), chromium (Cr), and titanium (Ti) after hip arthroplasty. Serum Co, Cr, and Ti levels were measured in 80 nonconsecutive patients with well-functioning unilateral total hip arthroplasty and compared among 4 bearing surfaces: ceramic-on-ceramic (CoC); ceramic-on-polyethylene (CoP); metal-on-polyethylene (MoP), and dual mobility (DM). The preoperative and most recent University of California, Los Angeles (UCLA) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were compared among the different bearing surfaces. No significant difference was found among serum Co and Cr levels between the 4 bearing surface groups (P = .0609 and P = .1577). Secondary analysis comparing metal and ceramic femoral heads demonstrated that the metal group (MoP, modular dual mobility (Stryker Orthopedics, Mahwah, NJ) [metal]) had significant higher serum Co levels compared with the ceramic group (CoC, CoP, MDM [ceramic]) (1.05 mg/L ± 1.25 vs 0.59 mg/L ± 0.24; P = .0411). Spearman coefficient identified no correlation between metal ion levels and patient-reported outcome scores. No serum metal ion level differences were found among well-functioning total hip arthroplasty with modern bearing couples. Significantly higher serum Co levels were seen when comparing metal vs ceramic femoral heads in this study and warrants further investigation. Metal ion levels did not correlate with patient-reported outcome measures. Copyright © 2016 Elsevier Inc. All rights reserved.

Morphology of compressed dipalmitoyl phosphatidylcholine monolayers investigated by atomic force microscopy

International Nuclear Information System (INIS)

Yang, Y.-P.; Tsay, R.-Y.

2007-01-01

The effectiveness of a substitute of natural lung surfactants on replacement therapy strongly depends on the stability of the monolayer of those substitute molecules. An atomic force microscope is utilized to investigate the microstructure of the films of the major components of natural lung surfactants, dipalmitoyl phosphatidylcholine-DPPC, which are transferred to mica substrates by the Langmuir-Blodgett film technique. A concave deformation structure was first observed for DPPC in solid phase. The depth of the concave domain was about 6 nm and was remarkably uniform. For a collapsed DPPC monolayer, the surface film consists of a granular convex multilayer structure and a disc-like concave structure. Dynamic cyclic compression-expansion experiments indicate that the formation of the concave domain is a reversible process while the process for convex multilayer formation is irreversible. This gives direct evidence that convex grain is the collapsed structure of DPPC monolayer and the concave shallow disc corresponds to the elastic deformation of a DPPC solid film. Results of atomic force microscopy indicate that the nucleation and growth model instead of the fracture model can better describe the collapse behavior of a DPPC monolayer

Evaluation of bubbler/diaphragm techniques to measure surface level in the waste storage tanks

International Nuclear Information System (INIS)

Peters, T.J.; Hickman, B.J.; Colson, J.B.

1993-10-01

This report describes the results of tests conducted at the Pacific Northwest Laboratory (PNL) to determine if a bubbler technique can be used to determine the surface level in the waste tanks. Two techniques were evaluated. The first technique is a standard bubbler system in which a tube is placed below the surface of the liquid to be measured and air pressure inside a tube is increased until bubbles begin to become emitted from the tube. The air pressure then is a function of the pressure at the bottom of the tube. The second technique involves a system similar to the standard bubbler technique, but instead of bubbles being released into the material to be gauged, air pressure is increased against a diaphragm until enough pressure is applied to overcome the pressure of the liquid at the given depth, at which time the air then flows in a return loop back to a vent. The advantage of the diaphragm system is that it is a sealed system; thus no air is released into the waste tank materials, and it is not possible for the waste tank materials to get into the air flow. Based on the results of the tests conducted in this program, it appears that the bubbler and diaphragm systems that were tested could not be used for accurate measurements of the level in the waste tanks. Both exhibited deposits of simulated waste tank material at the end of the devices which affected the ability of the gauge to accurately determine changes in the surface level even though the measured value of the level was inaccurate. Further investigations into the cause of this inaccuracy may be warranted. Alternate diaphragm materials may improve the performance of this gauge

Low-Cost Alternative for the Measurement of Water Levels in Surface Water Streams

Directory of Open Access Journals (Sweden)

Luis E. PEÑA

2017-11-01

Full Text Available Flood risk management and water resources planning involve a deep knowledge of surface streams so that mitigation strategies and climate change adaptations can be implemented. Commercially, there is a wide range of technologies for the measurement of hydroclimatic variables; however, many of these technologies may not be affordable for institutions with limited budgets. This paper has two main objectives: 1 Present the design of an ultrasound-based water level measurement system, and 2 Propose a methodological alternative for the development of instruments, according to the needs of institutions conducting monitoring of surface waterbodies. To that end, the proposed methodology is based on selection processes defined according to the specific needs of each waterbody. The prototype was tested in real-world scale, with the potential to obtain accurate measurements. Lastly, we present the design of the ultrasound-based water level measurement instrument, which can be built at a low cost. Low-cost instruments can potentially contribute to the sustainable instrumental autonomy of environmental entities and help define measurement and data transmission standards based on the specific requirements of the monitoring.

Detecting Local Ligand-Binding Site Similarity in Non-Homologous Proteins by Surface Patch Comparison

Science.gov (United States)

Sael, Lee; Kihara, Daisuke

2012-01-01

Functional elucidation of proteins is one of the essential tasks in biology. Function of a protein, specifically, small ligand molecules that bind to a protein, can be predicted by finding similar local surface regions in binding sites of known proteins. Here, we developed an alignment free local surface comparison method for predicting a ligand molecule which binds to a query protein. The algorithm, named Patch-Surfer, represents a binding pocket as a combination of segmented surface patches, each of which is characterized by its geometrical shape, the electrostatic potential, the hydrophobicity, and the concaveness. Representing a pocket by a set of patches is effective to absorb difference of global pocket shape while capturing local similarity of pockets. The shape and the physicochemical properties of surface patches are represented using the 3D Zernike descriptor, which is a series expansion of mathematical 3D function. Two pockets are compared using a modified weighted bipartite matching algorithm, which matches similar patches from the two pockets. Patch-Surfer was benchmarked on three datasets, which consist in total of 390 proteins that bind to one of 21 ligands. Patch-Surfer showed superior performance to existing methods including a global pocket comparison method, Pocket-Surfer, which we have previously introduced. Particularly, as intended, the accuracy showed large improvement for flexible ligand molecules, which bind to pockets in different conformations. PMID:22275074

Unusual shapes for a catenary under the effects of surface tension and gravity: A variational treatment

International Nuclear Information System (INIS)

Behroozi, F.; Mohazzabi, P.; McCrickard, J.

1995-01-01

The familiar catenary is the shape assumed by a chain or string as it hangs from two points. The mathematical equation of the catenary was first published more than three hundred years ago by Leibnitz and Huygen, among others. Here we consider the shapes assumed by a hanging string in the presence of gravity and surface tension. The surface tension is introduced by suspending the string from a thin horizontal rod while the area bounded by the string and the rod is covered with a soap film. The string then assumes new and wonderful shapes depending on the relative strength of the surface tension and the weight per unit length of the string. When surface tension dominates, the string is pulled inward, assuming a convex shape similar to the Greek letter γ. On the other hand, when gravity is dominant the string is pulled outward and assumes a concave shape best described as a distorted catenary. However, when the gravitational force normal to the string matches the surface tension, the string takes a linear configuration similar to the letter V. Under suitable conditions, the string can be made to assume any of the three configurations by adjusting the separation of its end points. The equations that describe the shape of the string are derived by minimizing the total energy of the system and are presented for the three principal configurations

Implications of long-term surface or near-surface storage of intermediate and low-level wastes in the UK

International Nuclear Information System (INIS)

Murray, N.; Vande Putte, D.; Ware, R.J.

1986-02-01

Various options for 200 year-long storage of all Low- and Intermediate-Level wastes generated to the year 2030 are considered. On-site storage and centralised storage have been examined and compared. The feasibility of storing some of the wastes in underground facilities that are convertible to repositories has been demonstrated, but it is shown that centralised, surface storage of wastes would be more economical. There appears to be little merit in storing Intermediate Level wastes in separate facilities that could be converted to repositories. Storage is shown to be more expensive than direct disposal, except if future costs are discounted by more than about 10%. With carefully designed stores and remote handling, the collective dose to operators could be limited to about 20-40 man Sv over the whole period of storage. (author)

Past and future sea-level change from the surface mass balance of glaciers

Directory of Open Access Journals (Sweden)

B. Marzeion

2012-11-01

Full Text Available We present estimates of sea-level change caused by the global surface mass balance of glaciers, based on the reconstruction and projection of the surface mass balance of all the individual glaciers of the world, excluding the ice sheets in Greenland and Antarctica. The model is validated using a leave-one-glacier-out cross-validation scheme against 3997 observed surface mass balances of 255 glaciers, and against 756 geodetically observed, temporally integrated volume and surface area changes of 341 glaciers. When forced with observed monthly precipitation and temperature data, the glaciers of the world are reconstructed to have lost mass corresponding to 114 ± 5 mm sea-level equivalent (SLE between 1902 and 2009. Using projected temperature and precipitation anomalies from 15 coupled general circulation models from the Coupled Model Intercomparison Project phase 5 (CMIP5 ensemble, they are projected to lose an additional 148 ± 35 mm SLE (scenario RCP26, 166 ± 42 mm SLE (scenario RCP45, 175 ± 40 mm SLE (scenario RCP60, or 217 ± 47 mm SLE (scenario RCP85 during the 21st century. Based on the extended RCP scenarios, glaciers are projected to approach a new equilibrium towards the end of the 23rd century, after having lost either 248 ± 66 mm SLE (scenario RCP26, 313 ± 50 mm SLE (scenario RCP45, or 424 ± 46 mm SLE (scenario RCP85. Up until approximately 2100, ensemble uncertainty within each scenario is the biggest source of uncertainty for the future glacier mass loss; after that, the difference between the scenarios takes over as the biggest source of uncertainty. Ice mass loss rates are projected to peak 2040 ∼ 2050 (RCP26, 2050 ∼ 2060 (RCP45, 2070 ∼ 2090 (RCP60, or 2070 ∼ 2100 (RCP85.

Ray splitting in the reflection and refraction of surface acoustic waves in anisotropic solids.

Science.gov (United States)

Every, A G; Maznev, A A

2010-05-01

This paper examines the conditions for, and provides examples of, ray splitting in the reflection and refraction of surface acoustic waves (SAW) in elastically anisotropic solids at straight obstacles such as edges, surface breaking cracks, and interfaces between different solids. The concern here is not with the partial scattering of an incident SAW's energy into bulk waves, but with the occurrence of more than one SAW ray in the reflected and/or transmitted wave fields, by analogy with birefringence in optics and mode conversion of bulk elastic waves at interfaces. SAW ray splitting is dependent on the SAW slowness curve possessing concave regions, which within the constraint of wave vector conservation parallel to the obstacle allows multiple outgoing SAW modes for certain directions of incidence and orientation of obstacle. The existence of pseudo-SAW for a given surface provides a further channel for ray splitting. This paper discusses some typical material configurations for which SAW ray splitting occurs. An example is provided of mode conversion entailing backward reflection or negative refraction. Experimental demonstration of ray splitting in the reflection of a laser generated SAW in GaAs(111) is provided. The calculation of SAW mode conversion amplitudes lies outside the scope of this paper.

Surface Water Connectivity, Flow Pathways and Water Level Fluctuation in a Cold Region Deltaic Ecosystem

Science.gov (United States)

Peters, D. L.; Niemann, O.; Skelly, R.; Monk, W. A.; Baird, D. J.

2017-12-01

The Peace-Athabasca Delta (PAD) is a 6000 km2 deltaic floodplain ecosystem of international importance (Wood Buffalo National Park, Ramsar Convention, UNESCO World Heritage, and SWOT satellite water level calibration/validation site). The low-relief floodplain formed at the confluence of the Peace, Athabasca and Birch rivers with Lake Athabasca. More than 1000 wetland and lake basins have varying degrees of connectivity to the main flow system. Hydroperiod and water storage is influenced by ice-jam and open-water inundations and prevailing semi-arid climate that control water drawdown. Prior studies have identified pathways of river-to-wetland floodwater connection and historical water level fluctuation/trends as a key knowledge gaps, limiting our knowledge of deltaic ecosystem status and potential hydroecological responses to climate change and upstream water alterations to flow contributions. To address this knowledge gap, surface elevation mapping of the PAD has been conducted since 2012 using aerial remote sensing Light Detection and Ranging (LiDAR), plus thousands of ground based surface and bathymetric survey points tied to Global Positioning System (GPS) were obtained. The elevation information was used to develop a high resolution digital terrain model to simulate and investigate surface water connectivity. Importantly, the surveyed areas contain a set of wetland monitoring sites where ground-based surface water connectivity, water level/depth, water quality, and aquatic ecology (eg, vegetation, macroinvertebrate and muskrat) have been examined. The goal of this presentation is to present an assessment of: i) surface water fluctuation and connectivity for PAD wetland sites; ii) 40+ year inter-annual hydroperiod reconstruction for a perched basin using a combination of field measurements, remote sensing estimates, and historical documents; and iii) outline an approach to integrate newly available hydro-bio-geophysical information into a novel, multi

Assessment of the SMAP Level-4 Surface and Root-Zone Soil Moisture Product Using In Situ Measurements

NARCIS (Netherlands)

Reichle, Rolf H.; De Lannoy, Gabrielle J. M.; Liu, Qing; Ardizzone, Joseph V.; Colliander, Andreas; Conaty, Austin; Crow, Wade; Jackson, Thomas J.; Jones, Lucas A.; Kimball, John S.; Koster, Randal D.; Mahanama, Sarith P.; Smith, Edmond B.; Berg, Aaron; Bircher, Simone; Bosch, David; Caldwell, Todd G.; Cosh, Michael; Holifield Collins, Chandra D.; Jensen, Karsten H.; Livingston, Stan; Lopez-baeza, Ernesto; Martínez-fernández, José; Mcnairn, Heather; Moghaddam, Mahta; Pacheco, Anna; Pellarin, Thierry; Prueger, John; Rowlandson, Tracy; Seyfried, Mark; Starks, Patrick; Su, Bob; Thibeault, Marc; Van Der Velde, Rogier; Walker, Jeffrey; Wu, Xiaoling; Zeng, Yijian

2017-01-01

The Soil Moisture Active Passive (SMAP) mission Level-4 Surface and Root-Zone Soil Moisture (L4_SM) data product is generated by assimilating SMAP L-band brightness temperature observations into the NASA Catchment land surface model. The L4_SM product is available from 31 March 2015 to present

Prediction and Optimization of Phase Transformation Region After Spot Continual Induction Hardening Process Using Response Surface Method

Science.gov (United States)

Qin, Xunpeng; Gao, Kai; Zhu, Zhenhua; Chen, Xuliang; Wang, Zhou

2017-09-01

The spot continual induction hardening (SCIH) process, which is a modified induction hardening, can be assembled to a five-axis cooperating computer numerical control machine tool to strengthen more than one small area or relatively large area on complicated component surface. In this study, a response surface method was presented to optimize phase transformation region after the SCIH process. The effects of five process parameters including feed velocity, input power, gap, curvature and flow rate on temperature, microstructure, microhardness and phase transformation geometry were investigated. Central composition design, a second-order response surface design, was employed to systematically estimate the empirical models of temperature and phase transformation geometry. The analysis results indicated that feed velocity has a dominant effect on the uniformity of microstructure and microhardness, domain size, oxidized track width, phase transformation width and height in the SCIH process while curvature has the largest effect on center temperature in the design space. The optimum operating conditions with 0.817, 0.845 and 0.773 of desirability values are expected to be able to minimize ratio (tempering region) and maximize phase transformation width for concave, flat and convex surface workpieces, respectively. The verification result indicated that the process parameters obtained by the model were reliable.

How well Can We Classify SWOT-derived Water Surface Profiles?

Science.gov (United States)

Frasson, R. P. M.; Wei, R.; Picamilh, C.; Durand, M. T.

2015-12-01

The upcoming Surface Water Ocean Topography (SWOT) mission will detect water bodies and measure water surface elevation throughout the globe. Within its continental high resolution mask, SWOT is expected to deliver measurements of river width, water elevation and slope of rivers wider than ~50 m. The definition of river reaches is an integral step of the computation of discharge based on SWOT's observables. As poorly defined reaches can negatively affect the accuracy of discharge estimations, we seek strategies to break up rivers into physically meaningful sections. In the present work, we investigate how accurately we can classify water surface profiles based on simulated SWOT observations. We assume that most river sections can be classified as either M1 (mild slope, with depth larger than the normal depth), or A1 (adverse slope with depth larger than the critical depth). This assumption allows the classification to be based solely on the second derivative of water surface profiles, with convex profiles being classified as A1 and concave profiles as M1. We consider a HEC-RAS model of the Sacramento River as a representation of the true state of the river. We employ the SWOT instrument simulator to generate a synthetic pass of the river, which includes our best estimates of height measurement noise and geolocation errors. We process the resulting point cloud of water surface heights with the RiverObs package, which delineates the river center line and draws the water surface profile. Next, we identify inflection points in the water surface profile and classify the sections between the inflection points. Finally, we compare our limited classification of simulated SWOT-derived water surface profile to the "exact" classification of the modeled Sacramento River. With this exercise, we expect to determine if SWOT observations can be used to find inflection points in water surface profiles, which would bring knowledge of flow regimes into the definition of river reaches.

Iterative algorithm for reconstructing rotationally asymmetric surface deviation with pixel-level spatial resolution

Science.gov (United States)

Quan, Haiyang; Wu, Fan; Hou, Xi

2015-10-01

New method for reconstructing rotationally asymmetric surface deviation with pixel-level spatial resolution is proposed. It is based on basic iterative scheme and accelerates the Gauss-Seidel method by introducing an acceleration parameter. This modified Successive Over-relaxation (SOR) is effective for solving the rotationally asymmetric components with pixel-level spatial resolution, without the usage of a fitting procedure. Compared to the Jacobi and Gauss-Seidel method, the modified SOR method with an optimal relaxation factor converges much faster and saves more computational costs and memory space without reducing accuracy. It has been proved by real experimental results.

Laser surface processing with controlled nitrogen-argon concentration levels for regulated surface life time

Science.gov (United States)

Obeidi, M. Ahmed; McCarthy, E.; Brabazon, D.

2018-03-01

Laser surface modification can be used to enhance the mechanical properties of a material, such as hardness, toughness, fatigue strength, and corrosion resistance. Surface nitriding is a widely used thermochemical method of surface modification, in which nitrogen is introduced into a metal or other material at an elevated temperature within a furnace. It is used on parts where there is a need for increased wear resistance, corrosion resistance, fatigue life, and hardness. Laser nitriding is a novel method of nitriding where the surface is heated locally by a laser, either in an atmosphere of nitrogen or with a jet of nitrogen delivered to the laser heated site. It combines the benefits of laser modification with those of nitriding. Recent work on high toughness tool steel samples has shown promising results due to the increased nitrogen gas impingement onto the laser heated region. Increased surface activity and nitrogen adsorption was achieved which resulted in a deeper and harder surface compared to conventional hardening methods. In this work, the effects of the laser power, pulse repetition frequency, and overlap percentage on laser surface treatment of 316 L SST steel samples with an argon-nitrogen jet will be presented. Resulting microstructure, phase type, microhardness, and wear resistance are presented.

Strut fracture of Björk-Shiley convexo-concave valve in Japan--risk of small valve size--.

Science.gov (United States)

Watarida, S; Shiraishi, S; Nishi, T; Imura, M; Yamamoto, Y; Hirokawa, R; Fujita, M

2001-08-01

The Björk-Shiley convexo-concave (BSCC) prosthetic valve was introduced in 1979. Between 1979 and 1986, approximately 86,000 BSCC valves were implanted. By December 31, 1994, 564 complete strut fractures had been reported to the manufacture. We experienced a case of an outlet strut fracture and investigated the risk of BSCC prosthetic valve fractures in Japan. To investigate the risk factor of a strut fracture in Japan, we investigated published cases of strut fractures. Between 1979 and 1986, 2021 BSCC valves were implanted in Japan. By January 31, 2000, 11 complete strut fractures of 60-degree BSCC valves including our case had occurred. The patients were eight males and three females. The average age at valve replacement was 42.4+/-8.1 years, and nine of eleven (81.8%) were patients valve fractured was 47.7+/-6.4 years, and eight of eleven (72.7%) were patients valve were 27 mm (n=5) (45.5%), 29 mm (n=3) (27.2%), and 31 mm (n=3) (27.2%). Four patients died and seven patients survived. Although only 11 BSCC valve struts fractured and statistical analysis could not be performed, our findings suggest that the high risk group for a strut fracture in Japan is young male patients with a mitral valve, >= 27 mm in size with BSCC models manufactured before March 1982. When following-up patients with BSCC models manufactured before March 1982, the possibility of a strut fracture in all BSCC valve sizes should be kept in mind.

Migrating Pools in Yangtze River

NARCIS (Netherlands)

Li, Y.

2002-01-01

The severity and location of bank erosion and bed scour changes with the variation of water level. At low flows, the main flow thread tends to follow the concave bank. As the discharge increases, the flow tends to cut across the convex bar, to concentrate against concave bank only downstream the

3D surface parameterization using manifold learning for medial shape representation

Science.gov (United States)

Ward, Aaron D.; Hamarneh, Ghassan

2007-03-01

The choice of 3D shape representation for anatomical structures determines the effectiveness with which segmentation, visualization, deformation, and shape statistics are performed. Medial axis-based shape representations have attracted considerable attention due to their inherent ability to encode information about the natural geometry of parts of the anatomy. In this paper, we propose a novel approach, based on nonlinear manifold learning, to the parameterization of medial sheets and object surfaces based on the results of skeletonization. For each single-sheet figure in an anatomical structure, we skeletonize the figure, and classify its surface points according to whether they lie on the upper or lower surface, based on their relationship to the skeleton points. We then perform nonlinear dimensionality reduction on the skeleton, upper, and lower surface points, to find the intrinsic 2D coordinate system of each. We then center a planar mesh over each of the low-dimensional representations of the points, and map the meshes back to 3D using the mappings obtained by manifold learning. Correspondence between mesh vertices, established in their intrinsic 2D coordinate spaces, is used in order to compute the thickness vectors emanating from the medial sheet. We show results of our algorithm on real brain and musculoskeletal structures extracted from MRI, as well as an artificial multi-sheet example. The main advantages to this method are its relative simplicity and noniterative nature, and its ability to correctly compute nonintersecting thickness vectors for a medial sheet regardless of both the amount of coincident bending and thickness in the object, and of the incidence of local concavities and convexities in the object's surface.

Surface shift of the occupied and unoccupied 4f levels of the rare-earth metals

Science.gov (United States)

Aldén, M.; Johansson, B.; Skriver, H. L.

1995-02-01

The surface energy shifts of the occupied and unoccupied 4f levels for the lanthanide metals have been calculated from first principles by means of a Green's-function technique within the tight-binding linear muffin-tin orbitals method. We use the concept of complete screening to identify the occupied and unoccupied 4f energy level shifts as the surface segregation energy of a 4fn-1 and 4fn+1 impurity atom, respectively, in a 4fn host metal. The calculations include both initial- and final-state effects and give values that are considerably lower than those measured on polycrystalline samples as well as those found in previous initial-state model calculations. The present theory agrees well with very recent high-resolution, single-crystal film measurements for Gd, Tb, Dy, Ho, Er, Tm, and Lu. We furthermore utilize the unique possibility offered by the lanthanide metals to clarify the roles played by the initial and the different final states of the core-excitation process, permitted by the fact that the so-called initial-state effect is identical upon 4f removal and 4f addition. Surface energy and work function calculations are also reported.

GHRSST Level 4 DMI_OI North Sea and Baltic Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the Danish...

Self-reported quality of life and health among Björk-Shiley convexo-concave prosthetic heart valve patients.

Science.gov (United States)

Signorello, L B; Kennedy, J A; Richmond, R A; Sieu, K L; Blot, W J; Harrison, D C

2001-03-01

The risk of fracture of Björk-Shiley convexo-concave (BSCC) prosthetic heart valves has resulted in consideration of prophylactic explantation and replacement for patients with high-risk valves. Little information exists on perceived quality of life, health status, and serious morbidity among BSCC patients, including those who have undergone explantation. Self-administered questionnaires were completed by a cohort of 585 BSCC patients who participated in an X-ray imaging study to detect precursors to valve fracture up to seven years (average 3.9 years) previously. Responses from 31 explant patients were contrasted with those from 554 BSCC patients in whom explant surgery was not attempted. Perceived quality of life and health status and risk of hospitalization after participating in the imaging study varied considerably among patients, but on average tended not to differ significantly between those with and without explants. A slightly greater proportion of explantees tended to report both improved health status and high rates of heart attack and pacemaker implantation. The health status of these patients was, in general, considerably worse than previously reported among valve implant patients. Over half the cohort were hospitalized during follow up, and half were unable to walk up more than one flight of stairs without shortness of breath. The less than optimal health status of most BSCC patients and relatively high rates of morbidity should be taken into account when considering potential explantation of the valves.

Formation of halo-structures in oxygen isotopes through change of occupancy of levels near Fermi surface

International Nuclear Information System (INIS)

Bhattacharya, Rupayan

2000-01-01

Recently a new parametrisation of Skyrme interaction has been formulated in order to study the level inversions of A=9 isobars. The role of occupancy of 2s 1/2 level in determining the halo structures of O, N, C, B and Be nuclei was shown. A thorough investigation on the binding energies, rms charge, neutron and matter distribution and occupation probabilities of levels near the Fermi surface has been done in the present work

Fabrication of Surface Level Cu/SiCp Nanocomposites by Friction Stir Processing Route

Directory of Open Access Journals (Sweden)

Cartigueyen Srinivasan

2015-01-01

Full Text Available Friction stir processing (FSP technique has been successfully employed as low energy consumption route to prepare copper based surface level nanocomposites reinforced with nanosized silicon carbide particles (SiCp. The effect of FSP parameters such as tool rotational speed, processing speed, and tool tilt angle on microstructure and microhardness was investigated. Single pass FSP was performed based on Box-Behnken design at three factors in three levels. A cluster of blind holes 2 mm in diameter and 3 mm in depth was used as particulate deposition technique in order to reduce the agglomeration problem during composite fabrication. K-type thermocouples were used to measure temperature histories during FSP. The results suggest that the heat generation during FSP plays a significant role in deciding the microstructure and microhardness of the surface composites. Microstructural observations revealed a uniform dispersion of nanosized SiCp without any agglomeration problem and well bonded with copper matrix at different process parameter combinations. X-ray diffraction study shows that no intermetallic compound was produced after processing. The microhardness of nanocomposites was remarkably enhanced and about 95% more than that of copper matrix.

GHRSST Level 4 RTO Terra MODIS-AMSRE Day North America Regional Blended Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the JPL Physical...

GHRSST Level 4 RTO Terra MODIS-AMSRE Night North America Regional Blended Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the JPL Physical...

GHRSST Level 4 RTO Aqua MODIS-AMSRE Night North America Regional Blended Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the JPL Physical...

GHRSST Level 4 RTO Aqua MODIS-AMSRE Day North America Regional Blended Sea Surface Temperature Analysis (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the JPL Physical...

Surface Defects in Sheet Metal Forming: a Simulative Laboratory Device and Comparison with FE Analysis

Science.gov (United States)

Thuillier, Sandrine; Le Port, Alban; Manach, Pierre-Yves

2011-08-01

Surface defects are small concave imperfections that can develop during forming on outer convex panels of automotive parts like doors. They occur during springback steps, after drawing in the vicinity of bending over a curved line and flanging/hemming in the vicinity of the upper corner of a door. They can alter significantly the final quality of the automobile and it is of primary importance to deal with them as early as possible in the design of the forming tools. The aim of this work is to reproduce at the laboratory scale such a defect, in the case of the flanging along a curved edge, made of two orthogonal straight part of length 50 mm and joint by a curved line. A dedicated device has been designed and steel samples were tested. Each sample was measured initially (after laser cutting) and after flanging, with a 3D measuring machine. 2D profiles were extracted and the curvature was calculated. Surface defects were defined between points where the curvature sign changed. Isovalues of surface defect depth could then be plotted, thus displaying also the spatial geometry on the part surface. An experimental database has been created on the influence of process parameters like the flanging height and the flanging radius. Numerical simulations have been performed with the finite element code Abaqus to predict the occurrence of such surface defects and to analyze stress and strain distribution within the defect area.

The impact of accelerometer mounting methods on the level of vibrations recorded at ground surface

Directory of Open Access Journals (Sweden)

Krzysztof Czech

2014-08-01

Full Text Available The paper presents the results of field research based on the measurements of accelerations recorded at ground surface. The source of the vibration characterized by high repetition rate of pulse parameters was light falling weight deflectometer ZFG-01. Measurements of vibrations have been carried out using top quality high-precision measuring system produced by Brüel&Kiær. Accelerometers were mounted on a sandy soil surface at the measuring points located radially at 5-m and 10-m distances from the source of vibration. The paper analyses the impact that the method of mounting accelerometers on the ground has on the level of the recorded values of accelerations of vibrations. It has been shown that the method of attaching the sensor to the surface of the ground is crucial for the credibility of the performed measurements.[b]Keywords[/b]: geotechnics, surface vibrations, ground, vibration measurement

Time lag between the tropopause height and the levels of 7Be concentration in near surface air

Directory of Open Access Journals (Sweden)

Melas D.

2012-04-01

Full Text Available The concentration of 7Be at near surface air has been determined over 2009, a year of a deep solar minimum, in the region of Thessaloniki, Greece at 40°62′ N, 22°95'E. In geomagnetic latitudes over 40° N, the elevation of the tropopause during the warm summer months and the vertical exchange of air masses within the troposphere cause greater mixture of the air masses resulting in higher concentration levels for 7Be in surface air. The positive correlation between the monthly activity concentration of 7Be and the tropopause height (0.94, p < 0.0001, and also between 7Be concentration and the temperature T (°C (R = 0.97, p < 0.001, confirm that the increased rate of vertical transport within the troposphere, especially during warmer summer months, has as a result the descent to surface of air masses enriched in 7Be. However, the 7Be concentration levels in near surface air are not expected to respond immediately to the change of elevation of the tropopause. It was found that there's a time lag of ~ 3 days between the change in the daily surface concentrations of 7Be the change in the elevation of the tropopause.

Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

Science.gov (United States)

Jones, Perry M.; Trost, Jared J.; Erickson, Melinda L.

2016-10-19

OverviewThis study assessed lake-water levels and regional and local groundwater and surface-water exchanges near northeast Twin Cities Metropolitan Area lakes applying three approaches: statistical analysis, field study, and groundwater-flow modeling.  Statistical analyses of lake levels were completed to assess the effect of physical setting and climate on lake-level fluctuations of selected lakes. A field study of groundwater and surface-water interactions in selected lakes was completed to (1) estimate potential percentages of surface-water contributions to well water across the northeast Twin Cities Metropolitan Area, (2) estimate general ages for waters extracted from the wells, and (3) assess groundwater inflow to lakes and lake-water outflow to aquifers downgradient from White Bear Lake.  Groundwater flow was simulated using a steady-state, groundwater-flow model to assess regional groundwater and surface-water exchanges and the effects of groundwater withdrawals, climate, and other factors on water levels of northeast Twin Cities Metropolitan Area lakes.

Structure model index does not measure rods and plates in trabecular bone

Directory of Open Access Journals (Sweden)

Phil L Salmon

2015-10-01

Full Text Available Structure model index (SMI is widely used to measure rods and plates in trabecular bone. It exploits the change in surface curvature that occurs as a structure varies from spherical (SMI = 4, to cylindrical (SMI = 3 to planar (SMI = 0. The most important assumption underlying SMI is that the entire bone surface is convex and that the curvature differential is positive at all points on the surface. The intricate connections within the trabecular continuum suggest that a high proportion of the surface could be concave, violating the assumption of convexity and producing regions of negative differential. We implemented SMI in the BoneJ plugin and included the ability to measure the amounts of surface that increased or decreased in area after surface mesh dilation, and the ability to visualize concave and convex regions. We measured SMI and its positive (SMI+ and negative (SMI- components, bone volume fraction (BV/TV, the fraction of the surface that is concave (CF, and mean ellipsoid factor (EF in trabecular bone using 38 X-ray microtomography (XMT images from a rat ovariectomy model of sex steroid rescue of bone loss, and 169 XMT images from a broad selection of 87 species' femora (mammals, birds, and a crocodile. We simulated bone resorption by eroding an image of elephant trabeculae and recording SMI and BV/TV at each erosion step. Up to 70%, and rarely less than 20%, of the trabecular surface is concave (CF 0.155 – 0.700. SMI is unavoidably influenced by aberrations from SMI-, which is strongly correlated with BV/TV and CF. The plate-to-rod transition in bone loss is an erroneous observation resulting from SMI's close and artefactual relationship with BV/TV. SMI cannot discern between the distinctive trabecular geometries typical of mammalian and avian bone, whereas EF clearly detects birds' more plate-like trabeculae. EF is free from confounding relationships with BV/TV and CF. SMI results reported in the literature should be treated with

Lathe leveler

Energy Technology Data Exchange (ETDEWEB)

Lovelady, III, Michael W.J.

2018-03-06

A lathe leveler for centering a cutting tool in relation to a cylindrical work piece includes a first leveling arm having a first contact point disposed adjacent a distal end of the first leveling arm, a second leveling arm having a second contact point disposed adjacent a distal end of the second leveling arm, a leveling gage, and a leveling plate having a cutting tool receiving surface positioned parallel to a horizontal axis of the leveling gage and on a same plane as a midpoint of the first contact point and the second contact point. The leveling arms and leveling plate are dimensioned and configured such that the cutting tool receiving surface is centered in relation to the work piece when the first and second contact points are in contact with one of the inner surface and outer surface of the cylindrical work piece and the leveling gage is centered.

Surface shift of the occupied and unoccupied 4f levels of the rare-earth metals

DEFF Research Database (Denmark)

Aldén, Magnus; Johansson, Börje; Skriver, Hans Lomholt

1995-01-01

The surface energy shifts of the occupied and unoccupied 4f levels for the lanthanide metals have been calculated from first principles by means of a Green’s-function technique within the tight-binding linear muffin-tin orbitals method. We use the concept of complete screening to identify...... the occupied and unoccupied 4f energy level shifts as the surface segregation energy of a 4fn-1 and 4fn+1 impurity atom, respectively, in a 4fn host metal. The calculations include both initial- and final-state effects and give values that are considerably lower than those measured on polycrystalline samples...... as well as those found in previous initial-state model calculations. The present theory agrees well with very recent high-resolution, single-crystal film measurements for Gd, Tb, Dy, Ho, Er, Tm, and Lu. We furthermore utilize the unique possibility offered by the lanthanide metals to clarify the roles...

Mechanized covering application in equipment surfaces; Aplicacao mecanizada de revestimento em superficies de equipamentos

Energy Technology Data Exchange (ETDEWEB)

Abreu, Billy A. de; Broering, Carlos E. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica

2004-07-01

Facing such challenges, the main objective of this work is to develop automated equipment and new welding procedures to be used to repair tank reservoirs operating in corrosive media. The equipment is expected to be applied directly in the maintenance of petrochemical plants. The project consists on a mechanical displacement device, able to move along a flexible rail, which can be fixed to a concave or convex surface and fitting itself to the geometry. A transversal arm gives it a second movement ability, allowing oscillatory displacements and the exact positioning of the pistol. As it is widely known, the automated welding process results in a considerably increase in productivity and quality, when comparing to the hand made process. Therefore, knowing the parameters involved and adjusted the welding variables to the best values, it is expected to achieve welding free of imperfections, inconsistencies and errors, and able to be repetitive. (author)

Effects of Multilevel Facetectomy and Screw Density on Postoperative Changes in Spinal Rod Contour in Thoracic Adolescent Idiopathic Scoliosis Surgery.

Directory of Open Access Journals (Sweden)

Terufumi Kokabu

Full Text Available Flattening of the preimplantation rod contour in the sagittal plane influences thoracic kyphosis (TK restoration in adolescent idiopathic scoliosis (AIS surgery. The effects of multilevel facetectomy and screw density on postoperative changes in spinal rod contour have not been documented. This study aimed to evaluate the effects of multilevel facetectomy and screw density on changes in spinal rod contour from before implantation to after surgical correction of thoracic curves in patients with AIS prospectively. The concave and convex rod shapes from patients with thoracic AIS (n = 49 were traced prior to insertion. Postoperative sagittal rod shape was determined by computed tomography. The angle of intersection of the tangents to the rod end points was measured. Multiple stepwise linear regression analysis was used to identify variables independently predictive of change in rod contour (Δθ. Average Δθ at the concave and convex side were 13.6° ± 7.5° and 4.3° ± 4.8°, respectively. The Δθ at the concave side was significantly greater than that of the convex side (P < 0.0001 and significantly correlated with Risser sign (P = 0.032, the preoperative main thoracic Cobb angle (P = 0.031, the preoperative TK angle (P = 0.012, and the number of facetectomy levels (P = 0.007. Furthermore, a Δθ at the concave side ≥14° significantly correlated with the postoperative TK angle (P = 0.003, the number of facetectomy levels (P = 0.021, and screw density at the concave side (P = 0.008. Rod deformation at the concave side suggests that corrective forces acting on that side are greater than on the convex side. Multilevel facetectomy and/or screw density at the concave side have positive effects on reducing the rod deformation that can lead to a loss of TK angle postoperatively.

Study on high speed lithium jet for neutron source of boron neutron capture therapy (BNCT)

International Nuclear Information System (INIS)

Takahashi, Minoru; Kobayashi, Tooru; Zhang, Mingguang; Mak, Michael; Stefanica, Jiri; Dostal, Vaclav; Zhao Wei

2012-01-01

The feasibility study of a liquid lithium type proton beam target was performed for the neutron source of the boron neutron capture therapy (BNCT). As the candidates of the liquid lithium target, a thin sheet jet and a thin film flow on a concave wall were chosen, and a lithium flow experiment was conducted to investigate the hydrodynamic stability of the targets. The surfaces of the jets and film flows with a thickness of 0.5 mm and a width of 50 mm were observed by means of photography. It has been found that a stable sheet jet and a stable film flow on a concave wall can be formed up to certain velocities by using a straight nozzle and a curved nozzle with the concave wall, respectively. (author)

WE-A-17A-01: Absorbed Dose Rate-To-Water at the Surface of a Beta-Emitting Planar Ophthalmic Applicator with a Planar, Windowless Extrapolation Chamber

Energy Technology Data Exchange (ETDEWEB)

Riley, A [of Wisconsin Medical Radiation Research Center, Madison, WI (United States); Soares, C [NIST (Retired), Gaithersburg, MD (United States); Micka, J; Culberson, W [University of Wisconsin Medical Radiation Research Center, Madison, WI (United States); DeWerd, L [University of WIMadison/ ADCL, Madison, WI (United States)

2014-06-15

Purpose: Currently there is no primary calibration standard for determining the absorbed dose rate-to-water at the surface of β-emitting concave ophthalmic applicators and plaques. Machining tolerances involved in the design of concave window extrapolation chambers are a limiting factor for development of such a standard. Use of a windowless extrapolation chamber avoids these window-machining tolerance issues. As a windowless extrapolation chamber has never been attempted, this work focuses on proof of principle measurements with a planar, windowless extrapolation chamber to verify the accuracy in comparison to initial calibration, which could be extended to the design of a hemispherical, windowless extrapolation chamber. Methods: The window of an extrapolation chamber defines the electrical field, aids in aligning the source parallel to the collector-guard assembly, and decreases the backscatter due to attenuation of lower electron energy. To create a uniform and parallel electric field in this research, the source was made common to the collector-guard assembly. A precise positioning protocol was designed to enhance the parallelism of the source and collector-guard assembly. Additionally, MCNP5 was used to determine a backscatter correction factor to apply to the calibration. With these issues addressed, the absorbed dose rate-to-water of a Tracerlab 90Sr planar ophthalmic applicator was determined using National Institute of Standards and Technology's (NIST) calibration formalism, and the results of five trials with this source were compared to measurements at NIST with a traditional extrapolation chamber. Results: The absorbed dose rate-to-water of the planar applicator was determined to be 0.473 Gy/s ±0.6%. Comparing these results to NIST's determination of 0.474 Gy/s yields a −0.6% difference. Conclusion: The feasibility of a planar, windowless extrapolation chamber has been demonstrated. A similar principle will be applied to developing a

Relict benthic foraminifera in surface sediments off central east coast of India as indicator of sea level changes

Digital Repository Service at National Institute of Oceanography (India)

Rana, S.S.; Nigam, R.; Panchang, R.

surface samples is characteristic of coral reef environment and has been inferred as evidence for past low sea levels. Based on extrapolation of previously published radiocarbon dates from the region, we propose a pliable sea level curve for the period...

Occupational exposure to beryllium in French enterprises: a survey of airborne exposure and surface levels.

Science.gov (United States)

Vincent, Raymond; Catani, Jacques; Créau, Yvon; Frocaut, Anne-Marie; Good, Andrée; Goutet, Pierre; Hou, Alain; Leray, Fabrice; André-Lesage, Marie-Ange; Soyez, Alain

2009-06-01

An assessment survey of occupational exposure to beryllium (Be) was conducted in France between late 2004 and the end of 2006. Exposure estimates were based on the analytical results of samples collected from workplace air and from work surfaces in 95 facilities belonging to 37 sectors of activity. The results of this study indicated airborne Be concentrations in excess of the occupational exposure limit value of 2 microg m(-3) recommended in France. Metallurgy and electronic component manufacturing represented the activities and occupations where workers had the highest arithmetic mean exposures to Be. Surface contamination levels were also high and frequently exceeded thresholds recommended by different bodies. These results should prompt the development of prevention programmes that include Be substitution, process control and surface decontamination, in conjunction with suitable medical surveillance.

Planation surfaces as a record of medium to large wavelength deformation: the example of the Lake Albert Rift (Uganda) on the East African Dome

Science.gov (United States)

Brendan, Simon; François, Guillocheau; Cécile, Robin; Jean, Braun; Olivier, Dauteuil; Massimo, Dall'Asta

2016-04-01

African relief is characterized by planation surfaces, some of them of continental scale. These surfaces are slightly deformed according to different wavelengths (x10 km; x100 km, x1000 km) which record both mantle dynamics (very long wavelength, x 1000 km) and lithosphere deformation (long wavelength deformation, x 100 km). Different types of these planation surfaces are recognized: - Etchplains capped by iron-duricrust which correspond to erosional nearly flat weathered surfaces resulting from the growth of laterites under warm and humid conditions. - Pediments which define mechanical erosional surfaces with concave or rectilinear profiles delimited by upslope scarps connected upstream with the upper landforms. We here focused on the Lake Albert Rift at the northern termination of the western branch of the East African Rift System of which the two branches are surimposed on the East-African Dome. Different wavelengths of deformation were characterized based on the 3D mapping of stepped planation surfaces: (1) very long wavelength deformations resulting from the uplift of the East African Dome; (2) long wavelength deformations resulting from the opening of the eastern branch and (3) medium wavelength deformations represented by the uplift of rift shoulders like the Rwenzori Mountains. The paleo-landscape reconstruction of Uganda shows the existence of four generations of landforms dated according to their geometrical relationships with volcanic rocks. A four stepped evolution of the Ugandan landforms is proposed: • 70 - 22 Ma: generation of two weathered planation surfaces (etchplain Uw and Iw). The upper one (Uw) records a very humid period culminating at time of the Early Eocene Climatic Optimum (70-45 Ma). It corresponds to the African Surface. A first uplift of the East African Dome generates a second lower planation surface (Iw) connected to the Atlantic Ocean base level; • 17-2.7 Ma: planation of large pediplains connected to the local base level induced

OMI/Aura Surface Reflectance Climatology Level 3 Global 0.5deg Lat/Lon Grid V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI Earth Surface Reflectance Climatology product, OMLER (Global 0.5deg Lat/Lon grid) which is based on Version 003 Level-1B top of atmosphere upwelling radiance...

An improved empirical dynamic control system model of global mean sea level rise and surface temperature change

Science.gov (United States)

Wu, Qing; Luu, Quang-Hung; Tkalich, Pavel; Chen, Ge

2018-04-01

Having great impacts on human lives, global warming and associated sea level rise are believed to be strongly linked to anthropogenic causes. Statistical approach offers a simple and yet conceptually verifiable combination of remotely connected climate variables and indices, including sea level and surface temperature. We propose an improved statistical reconstruction model based on the empirical dynamic control system by taking into account the climate variability and deriving parameters from Monte Carlo cross-validation random experiments. For the historic data from 1880 to 2001, we yielded higher correlation results compared to those from other dynamic empirical models. The averaged root mean square errors are reduced in both reconstructed fields, namely, the global mean surface temperature (by 24-37%) and the global mean sea level (by 5-25%). Our model is also more robust as it notably diminished the unstable problem associated with varying initial values. Such results suggest that the model not only enhances significantly the global mean reconstructions of temperature and sea level but also may have a potential to improve future projections.

Improving Limit Surface Search Algorithms in RAVEN Using Acceleration Schemes: Level II Milestone

Energy Technology Data Exchange (ETDEWEB)

Alfonsi, Andrea [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Rabiti, Cristian [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Mandelli, Diego [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Cogliati, Joshua Joseph [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Sen, Ramazan Sonat [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Smith, Curtis Lee [Idaho National Laboratory (INL), Idaho Falls, ID (United States)

2015-07-01

, subject of the analysis. These methodologies are named, in the RAVEN environment, adaptive sampling strategies. These methodologies infer system responses from surrogate models constructed from already existing samples (produced using high fidelity simulations) and suggest the most relevant location (coordinate in the input space) of the next sampling point to be explored in the uncertain/parametric domain. When using those methodologies, it is possible to understand features of the system response with a small number of carefully selected samples. This report focuses on the development and improvement of the limit surface search. The limit surface is an important concept in system reliability analysis. Without going into the details, which will be covered later in the report, the limit surface could be briefly described as an hyper-surface in the system uncertainty/parametric space separating the regions leading to a prescribed system outcome. For example, if the uncertainty/parametric space is the one generated by the reactor power level and the duration of the batteries, the system is a nuclear power plant and the system outcome discriminating variable is the clad failure in a station blackout scenario, then the limit surface separates the combinations of reactor power level and battery duration that lead to clad failure from the ones that do not.

Comparison between evaluations of the glenoid concavity by double oblique axial MR arthrography and clinical results in arthroscopic bankart repair

International Nuclear Information System (INIS)

Maeda, Shugo; Ishibashi, Yasuyuki; Tsuda, Eiichi; Yamamoto, Yuji; Toh, Satoshi; Sasaki, Taisuke

2011-01-01

The purpose of this study was to compare the findings obtained in the glenoid concavity by double oblique axial MR arthrography (DOA-MRA) and the clinical outcome after arthroscopic Bankart repair. The results in 57 shoulders of 50 patients who underwent arthroscopic Bankart repair were reviewed. The pre and postoperative lesions in the inferior glenohumeral ligament labrum complex (IGHLLC) were classified into 5 morphological types based on the DOA-MRA findings prominent (P), split (S), flat (F), detached (D), and capsular tear (C). The height and slope of the anterior labrum from the glenoid fossa were measured on the DOA-MRA images. The Japan Shoulder Society Shoulder Instability Score (JSS-SIS) system was used to evaluate the affected shoulder of all of the patients after surgery. There were no significant differences between the JSS-SISs of the shoulders in the P group, F group, and S+D group (recurrent Bankart lesion) 6 months postoperatively. There were significant increases in the slope and height of all of the shoulders as a whole between the preoperative period and 3 months postoperatively, but there were no statistically significant differences in the slope or height between 3 months and 6 months postoperatively. The initial capsulolabral buttress property was maintained at 6 months after arthroscopic Bankart repair, and there was no correlation between the morphology of the IGHLLC and the JSS-SISs. (author)

[Directions for reoperation of patients with Björk-Shiley convexo-concave valve prosthesis, based on long-term experience].

Science.gov (United States)

Yamaki, F; Nakano, K; Endo, M; Hashimoto, A; Koyanagi, H

1994-02-01

Although a high incidence of strut fracture of the Björk-Shiley convexo-concave (C-C) valve prosthesis has been reported, it is still controversial whether the prosthesis functioning normally should be replaced electively. To clarify our policy for this issue, we reviewed 28 patients who had undergone mitral valve replacement with a C-C valve prosthesis, and evaluated long-term results according to STS guidelines. The incidence of valve-related complications expressed as % patient-year were; structural deterioration 0.30, nonstructural dysfunction 0.30, thromboembolism 1.20. There were no thrombosed valves, anticoagulant-related hemorrhage or prosthetic valve endocarditis. The actuarial free rate after valve replacement with the C-C at 10 years, constructed by the Kaplan-Meier method, were compared with those with St. Jude Medical (SJM) valve prosthesis. (1) Actuarial survival: 77.9 vs 87.3 (NS), (2) Reoperation-free: 91.6 vs 98.0 (p valve-related complications: 71.2 vs 77.7 (NS). The long-term results with the C-C were compatible to those with a SJM valve prosthesis. However, if a strut fracture occurs, it is very difficult to save the patient's life. The hospital mortality of re-replacement of valve prosthesis during the last 10 years, at our institute, was 2.6%, which is almost equal to the cumulative risk of strut fracture of the C-C valve after 10 years (3.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Surface textures of quartz grains from Goa coast - An application of the scanning electron microscope

Digital Repository Service at National Institute of Oceanography (India)

Ambre, N.V.; Gujar, A.R.; Mislankar, P.G.

in the coastal area of Goa. Subaqueous environment is predominant and is revealed in the form of mechanical impact features like conchoidal breakage, abrasion marks, impact V-marks, grooves, concave fractures while chemically dominant environment shows etch V...

An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

Science.gov (United States)

Vinš, Václav; Hošek, Jan; Hykl, Jiří; Hrubý, Jan

2015-05-01

New experimental apparatus for measurement of the surface tension of liquids under the metastable supercooled state has been designed and assembled in the study. The measuring technique is similar to the method employed by P.T. Hacker [NACA TN 2510] in 1951. A short liquid thread of the liquid sample was sucked inside a horizontal capillary tube partly placed in a temperature-controlled glass chamber. One end of the capillary tube was connected to a setup with inert gas which allowed for precise tuning of the gas overpressure in order of hundreds of Pa. The open end of the capillary tube was precisely grinded and polished before the measurement in order to assure planarity and perpendicularity of the outer surface. The liquid meniscus at the open end was illuminated by a laser beam and observed by a digital camera. Application of an increasing overpressure of the inert gas at the inner meniscus of the liquid thread caused variation of the outer meniscus such that it gradually changed from concave to flat and subsequently convex shape. The surface tension at the temperature of the inner meniscus could be evaluated from the overpressure corresponding to exactly planar outer meniscus. Detailed description of the new setup together with results of the preliminary tests is provided in the study.

Reduction of Fermi level pinning and recombination at polycrystalline CdTe surfaces by laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Simonds, Brian J. [Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Kheraj, Vipul [Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Department of Applied Physics, S. V. National Institute of Technology, Surat 395 007 (India); Palekis, Vasilios; Ferekides, Christos [Electrical Engineering, University of South Florida, Tampa, Florida 33620 (United States); Scarpulla, Michael A., E-mail: scarpulla@eng.utah.edu [Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112 (United States)

2015-06-14

Laser processing of polycrystalline CdTe is a promising approach that could potentially increase module manufacturing throughput while reducing capital expenditure costs. For these benefits to be realized, the basic effects of laser irradiation on CdTe must be ascertained. In this study, we utilize surface photovoltage spectroscopy (SPS) to investigate the changes to the electronic properties of the surface of polycrystalline CdTe solar cell stacks induced by continuous-wave laser annealing. The experimental data explained within a model consisting of two space charge regions, one at the CdTe/air interface and one at the CdTe/CdS junction, are used to interpret our SPS results. The frequency dependence and phase spectra of the SPS signal are also discussed. To support the SPS findings, low-temperature spectrally-resolved photoluminescence and time-resolved photoluminescence were also measured. The data show that a modest laser treatment of 250 W/cm{sup 2} with a dwell time of 20 s is sufficient to reduce the effects of Fermi level pinning at the surface due to surface defects.

Simple fabrication of closed-packed IR microlens arrays on silicon by femtosecond laser wet etching

Science.gov (United States)

Meng, Xiangwei; Chen, Feng; Yang, Qing; Bian, Hao; Du, Guangqing; Hou, Xun

2015-10-01

We demonstrate a simple route to fabricate closed-packed infrared (IR) silicon microlens arrays (MLAs) based on femtosecond laser irradiation assisted by wet etching method. The fabricated MLAs show high fill factor, smooth surface and good uniformity. They can be used as optical devices for IR applications. The exposure and etching parameters are optimized to obtain reproducible microlens with hexagonal and rectangular arrangements. The surface roughness of the concave MLAs is only 56 nm. This presented method is a maskless process and can flexibly change the size, shape and the fill factor of the MLAs by controlling the experimental parameters. The concave MLAs on silicon can work in IR region and can be used for IR sensors and imaging applications.

Fabrication of Surface Level Cu/Si Cp Nano composites by Friction Stir Processing Route

International Nuclear Information System (INIS)

Srinivasan, R. C.; Karunanithi, M.

2015-01-01

Friction stir processing (FSP) technique has been successfully employed as low energy consumption route to prepare copper based surface level nano composites reinforced with nano sized silicon carbide particles (Si Cp). The effect of FSP parameters such as tool rotational speed, processing speed, and tool tilt angle on microstructure and microhardness was investigated. Single pass FSP was performed based on Box-Behnken design at three factors in three levels. A cluster of blind holes 2 mm in diameter and 3 mm in depth was used as particulate deposition technique in order to reduce the agglomeration problem during composite fabrication. K-type thermocouples were used to measure temperature histories during FSP. The results suggest that the heat generation during FSP plays a significant role in deciding the microstructure and microhardness of the surface composites. Microstructural observations revealed a uniform dispersion of nano sized Si Cp without any agglomeration problem and well bonded with copper matrix at different process parameter combinations. X-ray diffraction study shows that no intermetallic compound was produced after processing. The microhardness of nano composites was remarkably enhanced and about 95% more than that of copper matrix

Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

Energy Technology Data Exchange (ETDEWEB)

Puthirath, Anand B.; Varma, Sreekanth J.; Jayalekshmi, S., E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin, Kerala 682022 (India); Methattel Raman, Shijeesh [Nanophotonic and Optoelectronic Devices Laboratory, Department of Physics, Cochin University of Science and Technology, Cochin, Kerala 682022 (India)

2016-04-18

Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra can be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.

Relative impacts of worldwide tropospheric ozone changes and regional emission modifications on European surface-ozone levels

International Nuclear Information System (INIS)

Szopa, S.; Hauglustaine, D.A.

2007-01-01

Multi-scale models were applied to assess the surface ozone changes in 2030. Several emission scenarios are considered, ranging from (a) a pessimistic anthropogenic emission increase to (b) an optimistic decrease of emissions, and including (c) a realistic scenario that assumes the implementation of control legislations [CLE]. The two extreme scenarios lead respectively to homogeneous global increase and decrease of surface ozone, whereas low and inhomogeneous changes associated with a slight global increase of ozone are found for the CLE scenario. Over western Europe, for the CLE scenario, the benefit of European emission reduction is significantly counterbalanced by increasing global ozone levels. Considering warmer conditions over Europe and future emission modifications, the human health exposure to surface ozone is found to be significantly worsened. (authors)

Surface deformation as a guide to kinematics and three-dimensional shape of slow-moving, clay-rich landslides, Honolulu, Hawaii

Science.gov (United States)

Baum, R.L.; Messerich, J.; Fleming, R.W.

1998-01-01

Two slow-moving landslides in Honolulu, Hawaii, were the subject of photogrammetric measurements, field mapping, and subsurface investigation to learn whether surface observations can yield useful information consistent with results of subsurface investigation. Mapping focused on structural damage and on surface features such as scarps, shears, and toes. The x-y-z positions of photo-identifiable points were obtained from aerial photographs taken at three different times. The measurements were intended to learn if the shape of the landslide failure surface can be determined from systematic surface observations and whether surface observations about deformation are consistent with photogrammetrically-obtained displacement gradients. Field and aerial photographic measurements were evaluated to identify the boundaries of the landslides, distinguish areas of incipient landslide enlargement, and identify zones of active and passive failure in the landslides. Data reported here apply mainly to the Alani-Paty landslide, a translational, earth-block landslide that damaged property in a 3.4-ha residential area. It began moving in the 1970s and displacement through 1991 totaled 4 m. Thickness, determined from borehole data, ranges from about 7 to 10 m; and the slope of the ground surface averages about 9??. Field evidence of deformation indicated areas of potential landslide enlargement outside the well-formed landslide boundaries. Displacement gradients obtained photogrammetrically and deformation mapping both identified similar zones of active failure (longitudinal stretching) and passive failure (longitudinal shortening) within the body of the landslide. Surface displacement on the landslide is approximately parallel to the broadly concave slip surface.

Residue determination and levels of glyphosate in surface waters, sediments and soils associated with oil palm plantation in Tasik Chini, Pahang, Malaysia

Science.gov (United States)

Mardiana-Jansar, K.; Ismail, B. S.

2014-09-01

Levels of glyphosate and its main metabolite were determined in surface water, soil and sediment samples from an oil palm plantation area located at Tasik Chini, Pahang, Malaysia. The optimization analytical method has been developed for the determination of glyphosate herbicide and its metabolite amino-methyl-phosphonic acid (AMPA) in surface waters to a level of 0.1μg/L, while in sediments and soils to a level of 0.5μg/g with a good linearity in the calibration range of 1-100μg/L. The procedure involves a pre-columnderivatization step with 9-fluorenyl-methyl-chloroformate (FMOC-Cl) yielding highly fluorescent derivatives of the analytes which can be determined by HPLC with fluorescence detection. In the field, levels of glyphosate in surface waters ranges from not detected to 1.0mg/L, while in soils and sediments were from not detected to 6.0mg/kg. For AMPA, the residues in surface waters were between not detected to 2.0mg/L, while in soil and sediment samples were from not detected to 5mg/kg. This variation of glyphosate and AMPA levels depended directly on time of pesticide application and the season.

Orientation-dependent surface core-level shifts and chemical shifts on clean and H 2S-covered GaAs

Science.gov (United States)

Ranke, W.; Finster, J.; Kuhr, H. J.

1987-08-01

Photoelectron spectra of the As 3d and Ga 3d core levels were studied in situ on a cylindrically shaped GaAs single crystal for the six inequivalent orientations (001), (113), (111), (110), (11¯1) and (11¯3). On the clean surface, prepared by molecular beam epitaxy (MBE), surface core levels are shifted by 0.25 to 0.55 eV towards smaller binding energy (BE) for As 3d and -0.25 to -0.35 eV towards higher BE for Ga, depending on orientation. Additional As causes As 3d contributions shifted between -0.45 and -0.7 eV towards higher BE. The position and intensity of them is influenced by H 2S adsorption. At 150 K, H 2S adsorbs preferentially on As sites. As chemical shifts appear at -0.6 to -0.9 eV towards higher BE. Simultaneously, As accumulation occurs on all orientations with the exception of (110). High temperature adsorption (550 K, 720 K) influences mainly the Ga 3d peaks. Two peaks shifted by about -0.45 and -0.8 eV towards higher Be were found which are attributed to Ga atoms with one or two sulfur ligands, respectively. At 720 K, also As depletion is observed. The compatibility of surface core-level positions and intensities with recent structural models for the (111) and (11¯1) surfaces is discussed.

Response of groundwater level and surface-water/groundwater interaction to climate variability: Clarence-Moreton Basin, Australia

Science.gov (United States)

Cui, Tao; Raiber, Matthias; Pagendam, Dan; Gilfedder, Mat; Rassam, David

2018-03-01

Understanding the response of groundwater levels in alluvial and sedimentary basin aquifers to climatic variability and human water-resource developments is a key step in many hydrogeological investigations. This study presents an analysis of groundwater response to climate variability from 2000 to 2012 in the Queensland part of the sedimentary Clarence-Moreton Basin, Australia. It contributes to the baseline hydrogeological understanding by identifying the primary groundwater flow pattern, water-level response to climate extremes, and the resulting dynamics of surface-water/groundwater interaction. Groundwater-level measurements from thousands of bores over several decades were analysed using Kriging and nonparametric trend analysis, together with a newly developed three-dimensional geological model. Groundwater-level contours suggest that groundwater flow in the shallow aquifers shows local variations in the close vicinity of streams, notwithstanding general conformance with topographic relief. The trend analysis reveals that climate variability can be quickly reflected in the shallow aquifers of the Clarence-Moreton Basin although the alluvial aquifers have a quicker rainfall response than the sedimentary bedrock formations. The Lockyer Valley alluvium represents the most sensitively responding alluvium in the area, with the highest declining (-0.7 m/year) and ascending (2.1 m/year) Sen's slope rates during and after the drought period, respectively. Different surface-water/groundwater interaction characteristics were observed in different catchments by studying groundwater-level fluctuations along hydrogeologic cross-sections. The findings of this study lay a foundation for future water-resource management in the study area.

Dynamic factor modeling of ground and surface water levels in an agricultural area adjacent to Everglades National Park

Science.gov (United States)

Ritter, A.; Muñoz-Carpena, R.

2006-02-01

The extensive eastern boundary of Everglades National Park (ENP) in south Florida (USA) is subject to one the most expensive and ambitious environmental restoration projects in history. Understanding and predicting the interaction between the shallow aquifer and surface water is a key component for fine-tuning the process. The Frog Pond is an intensively instrumented agricultural 2023 ha area adjacent to ENP. The interactions among 21 multivariate daily time series (ground and surface water elevations, rainfall and evapotranspiration) available from this area were studied by means of dynamic factor analysis, a novel technique in the field of hydrology. This method is designed to determine latent or background effects governing variability or fluctuations in non-stationary time series. Water levels in 16 wells and two drainage ditch locations inside the area were selected as response variables, and canal levels and net recharge as explanatory variables. Elevations in the two canals delimiting the Frog Pond area were found to be the main factors explaining the response variables. This influence of canal elevations on water levels inside the area was complementary and inversely related to the distance between the observation point and each canal. Rainfall events do not affect daily water levels significantly but are responsible for instantaneous or localized groundwater responses that in some cases can be directly associated with the risk of flooding. This close coupling between surface and groundwater levels, that corroborates that found by other authors using different methods, could hinder on-going environmental restoration efforts in the area by bypassing the function of wetlands and other surface features. An empirical model with a reduced set of parameters was successfully developed and validated in the area by interpolating the results from the dynamic factor analysis across the spatial domain (coefficient of efficiency across the domain: 0.66-0.99). Although

An intuitive concept for manufacturing and inspecting of aspherical components

Science.gov (United States)

Chou, Hsiao-Yu; Chang, Keng-Shou

2011-09-01

In this paper we propose an intuitive concept for manufacturing and inspecting of aspherical components. Two types, parabolic and cylinder, of plano-convex and plano-concave aspherical lenses were made by LOH 120S form generation machine. Three form error measurement methods were used known as coordinate measuring machine (CMM), interferometer with CGH null lens and inspection with combined pair lenses. Ultra high accuracy CMM from Panasonic Co., CGH cylinder null and CGH aspheric null from Diffraction International and OWI 150 ASPH CGH interferometer from OptoTech GmbH play the roll for measurement. CMM was used as a surface profiler to inspect the surface shape, and the software GRAPHER was also used as analysis tool to exam asphere numerical datum. The difference between theoretical and practical is as a surface polishing revised reference. The finished plano-convex and plano-concave aspherical lenses can be combined to be a plane lens. The individual and combined lenses were inspected on OPTOTECH OWI 150 ASPH CGH interferometer. The compared interference patterns have shown with the Diffration International CGH Aspheric Null "ASPHERIC 1" and CGH Cylinder Null "H80F2C". Through the procedure, the combined plano-convex and plano-concave aspherical lenses should be a perfect match plane lens and the individual lens might be an aspherical test standard element for quick inspection.

Project of the Year Submittal SY-101 Surface Level Rise Remediation Project

International Nuclear Information System (INIS)

BAUER, R.E.

2001-01-01

CH2M HILL Hanford Group is pleased to nominate the SY-101 Surface Level Rise Remediation Project (SLRRP) for the Project Management Institute's consideration as International Project of the Year for 2001. We selected this project as being our best recent example of effective project management, having achieved and exceeded our client's expectations in resolving urgent safety issues related to the storage of high level nuclear waste. In reflection, we consider the SY-101 SLRRP to be a prime example of safe and effective project delivery. The pages that follow present the tools and techniques employed to manage this complex and technically challenging project. Our objective in submitting this nomination is twofold--to share the lessons we have learned with other organizations, and to honor the men and women who contributed to this endeavor. It was by their diligent effort that the successes we relate here were accomplished 10 months ahead of schedule and one million dollars below the authorized budget

Cell surface N-glycans influence the level of functional E-cadherin at the cell–cell border

Directory of Open Access Journals (Sweden)

M. Kristen Hall

2014-01-01

Full Text Available E-cadherin is crucial for adhesion of cells to each other and thereby development and maintenance of tissue. While it is has been established that N-glycans inside the cell impact the level of E-cadherin at the cell surface of epithelial-derived cells, it is unclear whether N-glycans outside the cell control the clustering of E-cadherin at the cell–cell border. Here, we demonstrate reduction of N-glycans at the cell surface weakened the recruitment and retention of E-cadherin at the cell–cell border, and consequently reduced the strength of cell–cell interactions. We conclude that N-glycans at the cell surface are tightly linked to the placement of E-cadherin at the cell–cell border and thereby control E-cadherin mediated cell–cell adhesion.

Hydraulics and drones: observations of water level, bathymetry and water surface velocity from Unmanned Aerial Vehicles

DEFF Research Database (Denmark)

Bandini, Filippo

-navigable rivers and overpass obstacles (e.g. river structures). Computer vision, autopilot system and beyond visual line-of-sight (BVLOS) flights will ensure the possibility to retrieve hyper-spatial observations of water depth, without requiring the operator to access the area. Surface water speed can......The planet faces several water-related threats, including water scarcity, floods, and pollution. Satellite and airborne sensing technology is rapidly evolving to improve the observation and prediction of surface water and thus prevent natural disasters. While technological developments require....... Although UAV-borne measurements of surface water speed have already been documented in the literature, a novel approach was developed to avoid GCPs. This research is the first demonstration that orthometric water level can be measured from UAVs with a radar system and a GNSS (Global Navigation Satellite...

Composite Fermi surface in the half-filled Landau level with anisotropic electron mass

Science.gov (United States)

Ippoliti, Matteo; Geraedts, Scott; Bhatt, Ravindra

We study the problem of interacting electrons in the lowest Landau level at half filling in the quantum Hall regime, when the electron dispersion is given by an anisotropic mass tensor. Based on experimental observations and theoretical arguments, the ground state of the system is expected to consist of composite Fermions filling an elliptical Fermi sea, with the anisotropy of the ellipse determined by the competing effects of the isotropic Coulomb interaction and anisotropic electron mass tensor. We test this idea quantitatively by using a numerical density matrix renormalization group method for quantum Hall systems on an infinitely long cylinder. Singularities in the structure factor allow us to map the Fermi surface of the composite Fermions. We compute the composite Fermi surface anisotropy for several values of the electron mass anisotropy which allow us to deduce the functional dependence of the former on the latter. This research was supported by Department of Energy Office of Basic Energy Sciences through Grant No. DE-SC0002140.

Investigation of Surface Pre-Treatment Methods for Wafer-Level Cu-Cu Thermo-Compression Bonding

Directory of Open Access Journals (Sweden)

Koki Tanaka

2016-12-01

Full Text Available To increase the yield of the wafer-level Cu-Cu thermo-compression bonding method, certain surface pre-treatment methods for Cu are studied which can be exposed to the atmosphere before bonding. To inhibit re-oxidation under atmospheric conditions, the reduced pure Cu surface is treated by H2/Ar plasma, NH3 plasma and thiol solution, respectively, and is covered by Cu hydride, Cu nitride and a self-assembled monolayer (SAM accordingly. A pair of the treated wafers is then bonded by the thermo-compression bonding method, and evaluated by the tensile test. Results show that the bond strengths of the wafers treated by NH3 plasma and SAM are not sufficient due to the remaining surface protection layers such as Cu nitride and SAMs resulting from the pre-treatment. In contrast, the H2/Ar plasma–treated wafer showed the same strength as the one with formic acid vapor treatment, even when exposed to the atmosphere for 30 min. In the thermal desorption spectroscopy (TDS measurement of the H2/Ar plasma–treated Cu sample, the total number of the detected H2 was 3.1 times more than the citric acid–treated one. Results of the TDS measurement indicate that the modified Cu surface is terminated by chemisorbed hydrogen atoms, which leads to high bonding strength.

An analysis to optimize the process parameters of friction stir welded ...

African Journals Online (AJOL)

user

International Journal of Engineering, Science and Technology .... Figure.2 Schematic representation of (a) flat shoulder with cylindrical pin and (b) concave ... gap between the plate surface and tool shoulder which creates some pressure over ..... surface of the stir zone consists of fully ferritic grains, below the layer by which ...

GHRSST Level 4 AVHRR_OI Global Blended Sea Surface Temperature Analysis (GDS version 2) from NCEI (GDS versions 1 and 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) global Level 4 sea surface temperature analysis produced daily on a 0.25 degree grid at the NOAA...

Strut fracture with Björk-Shiley 70 degrees convexo-concave valve. An international multi-institutional follow-up study.

Science.gov (United States)

Ericsson, A; Lindblom, D; Semb, G; Huysmans, H A; Thulin, L I; Scully, H E; Bennett, J G; Ostermeyer, J; Grunkemeier, G L

1992-01-01

Between 1980 and 1983, 831 Björk-Shiley 70 degrees convexo-concave prosthetic heart valves were implanted at five institutions in Sweden, Germany. The Netherlands, and Canada. As of January 1991, there were 34 outlet strut fractures occurring from 0.2 to 10.1 years (median = 4.6 years) after implantation. In addition, there were 28 sudden, unexplained deaths. The mortality after strut fracture was 84%. The mortality after emergency valve replacement for strut fracture was 50%. The 10-year actuarial fracture rate (standard error) was 10.5 (2.4)% for large (29-33 mm) valves vs. 3.3 (1.2)% for 21-27 mm valves (P less than 0.001). Within valve size groups, fracture rates for aortic and mitral valves were similar. Cox regression analysis found only valve size to be significantly associated with strut fracture. There is a further subgrouping of the valves according to the manufacturer: group I are the earlier large 29-33 mm) valves; group II are the later large valves; group III are the small size (21-27 mm) valves. The risk of strut fracture was highest in group I (12.3% at 10 years) with an approximatively constant hazard (1.4% per year). A comparison was made with a statistical model incorporating all cases reported to the manufacturer. This model estimates fracture rates approximately 63%-73% of those found in the present study. These findings lead us to recommend that group I patients should be considered for elective reoperation on an individual basis, giving careful attention to risk factors and contraindications.

Digital data storage of core image using high resolution full color core scanner; Kokaizodo full color scanner wo mochiita core image no digital ka

Energy Technology Data Exchange (ETDEWEB)

Takahashi, W; Ujo, S; Osato, K; Takasugi, S [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan)

1996-05-01

This paper reports on digitization of core images by using a new type core scanner system. This system consists of a core scanner unit (equipped with a CCD camera), a personal computer and ancillary devices. This is a modification of the old type system, with measurable core length made to 100 cm/3 scans, and resolution enhanced to 5100 pixels/m (1024 pixels/m in the old type). The camera was changed to that of a color specification, and the A/D conversion was improved to 24-bit full color. As a result of carrying out a detail reproduction test on digital images of this core scanner, it was found that objects can be identified at a level of about the size of pixels constituting the image in the case when the best contrast is obtained between the objects and the background, and that in an evaluation test on visibility of concaves and convexes on core surface, reproducibility is not very good in large concaves and convexes. 2 refs., 6 figs.

The effect of a soap film on a catenary: measurement of surface tension from the triangular configuration

International Nuclear Information System (INIS)

Behroozi, F; Behroozi, P S

2011-01-01

A chain assumes the well-known shape known as a catenary when it hangs loosely from two points in a gravitational field. The correct solution of the catenary was one of the early triumphs of the newly invented calculus of variations at the end of the 17th century. Here we revisit the catenary and show that, for a chain hanging from a horizontal rod, three new and distinct configurations are possible if a soap film covers the area bounded by the chain and the rod. We first review the general problem and discuss the conditions under which the chain assumes a concave, triangular or convex configuration. The deciding factor is the strength of surface tension relative to the gravitational force per unit length of the chain. The conditions under which the chain assumes the shape of a perfect triangle are discussed in greater detail and analysed to obtain the tension along the chain. The triangular configuration is especially intriguing to undergraduates and may be used as a simple experiment to obtain the surface tension of the soap solution by measuring just one angle of the triangle.

The effect of a soap film on a catenary: measurement of surface tension from the triangular configuration

Energy Technology Data Exchange (ETDEWEB)

Behroozi, F [Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614 (United States); Behroozi, P S, E-mail: behroozi@uni.edu [Department of Physics, Stanford University, Stanford, CA 94305 (United States)

2011-09-15

A chain assumes the well-known shape known as a catenary when it hangs loosely from two points in a gravitational field. The correct solution of the catenary was one of the early triumphs of the newly invented calculus of variations at the end of the 17th century. Here we revisit the catenary and show that, for a chain hanging from a horizontal rod, three new and distinct configurations are possible if a soap film covers the area bounded by the chain and the rod. We first review the general problem and discuss the conditions under which the chain assumes a concave, triangular or convex configuration. The deciding factor is the strength of surface tension relative to the gravitational force per unit length of the chain. The conditions under which the chain assumes the shape of a perfect triangle are discussed in greater detail and analysed to obtain the tension along the chain. The triangular configuration is especially intriguing to undergraduates and may be used as a simple experiment to obtain the surface tension of the soap solution by measuring just one angle of the triangle.

Long-term effects of surface coal mining on ground-water levels and quality in two small watersheds in eastern Ohio

International Nuclear Information System (INIS)

Cunningham, W.L.; Jones, R.L.

1990-01-01

Two small eastern Ohio watersheds surface mined for coal and reclaimed were studied during 1986-89. Water level and water quality data were compared with data from investigations conducted during 1976-83 to determine long-term effects of surface mining on the hydrologic system. Before mining, the watersheds were characterized by flatlying sedimentary rocks above clay beds underlying two major coal seams. Two aquifers overlay each under clay. Surface mining removed the upper aquifer, stripped the coal seam, and replaced the spoil, creating a new aquifer with hydraulic and chemical characteristics different from those of the original upper aquifer. Water levels were measured continuously in one well in each aquifer and every 2 months in other wells. Water levels in upper aquifers reached hydraulic equilibrium from 2 to 5 years after mining and, in middle aquifers, water levels increased more than 5 ft during mining; equilibrium occurred almost immediately thereafter. Water samples were collected from three upper aquifer wells, one middle-aquifer well, a seep from the upper aquifer, and the stream in each watershed. Samples were collected in 1986, 1987, 1988, and 1989. In both watersheds, sulfate replaced bicarbonate as the dominant anion in the upper aquifer after mining. In general, significant increases in concentrations of dissolved constituents in groundwater resulted from surface mining. The continued decrease in pH indicates that groundwater had not reached complete geochemical equilibrium in either watershed more than 8 years after mining ended

Accurate prediction of complex free surface flow around a high speed craft using a single-phase level set method

Science.gov (United States)

Broglia, Riccardo; Durante, Danilo

2017-11-01

This paper focuses on the analysis of a challenging free surface flow problem involving a surface vessel moving at high speeds, or planing. The investigation is performed using a general purpose high Reynolds free surface solver developed at CNR-INSEAN. The methodology is based on a second order finite volume discretization of the unsteady Reynolds-averaged Navier-Stokes equations (Di Mascio et al. in A second order Godunov—type scheme for naval hydrodynamics, Kluwer Academic/Plenum Publishers, Dordrecht, pp 253-261, 2001; Proceedings of 16th international offshore and polar engineering conference, San Francisco, CA, USA, 2006; J Mar Sci Technol 14:19-29, 2009); air/water interface dynamics is accurately modeled by a non standard level set approach (Di Mascio et al. in Comput Fluids 36(5):868-886, 2007a), known as the single-phase level set method. In this algorithm the governing equations are solved only in the water phase, whereas the numerical domain in the air phase is used for a suitable extension of the fluid dynamic variables. The level set function is used to track the free surface evolution; dynamic boundary conditions are enforced directly on the interface. This approach allows to accurately predict the evolution of the free surface even in the presence of violent breaking waves phenomena, maintaining the interface sharp, without any need to smear out the fluid properties across the two phases. This paper is aimed at the prediction of the complex free-surface flow field generated by a deep-V planing boat at medium and high Froude numbers (from 0.6 up to 1.2). In the present work, the planing hull is treated as a two-degree-of-freedom rigid object. Flow field is characterized by the presence of thin water sheets, several energetic breaking waves and plungings. The computational results include convergence of the trim angle, sinkage and resistance under grid refinement; high-quality experimental data are used for the purposes of validation, allowing to

Surface anatomy and anatomical planes in the adult turkish population.

Science.gov (United States)

Uzun, C; Atman, E D; Ustuner, E; Mirjalili, S A; Oztuna, D; Esmer, T S

2016-03-01

Surface anatomy and anatomical planes are widely used in education and clinical practice. The planes are largely derived from cadaveric studies and their projections on the skin show discrepancies between and within anatomical reference textbooks. In this study, we reassessed the accuracy of common thoracic and abdominopelvic anatomical planes using computed tomography (CT) imaging in the live adult Turkish population. After patients with distorting pathologies had been excluded, CT images of 150 supine patients at the end tidal inspiration were analyzed. Sternal angle, transpyloric, subcostal, supracristal and pubic crest planes and their relationships to anatomical structures were established by dual consensus. The tracheal bifurcation, azygos vein/superior vena cava (SVC) junction and pulmonary bifurcation were usually below the sternal angle while the concavity of the aortic arch was generally within the plane. The tip of the tenth rib, the superior mesenteric artery and the portal vein were usually within the transpyloric plane while the renal hila and the fundus of the gallbladder were below it. The inferior mesenteric artery was below the subcostal plane and the aortic bifurcation was below the supracristal plane in most adults. Projectional surface anatomy is fundamental to medical education and clinical practice. Modern cross-sectional imaging techniques allow large groups of live patients to be examined. Classic textbook information regarding anatomy needs to be reviewed and updated using the data gathered from these recent studies, taking ethnic differences into consideration. © 2015 Wiley Periodicals, Inc.

Investigation of the Effect of Water Removal from Wells Surrounding Parishan Lake on Groundwater and Surface Water Levels

International Nuclear Information System (INIS)

Shafiei, M.; Raini Sarjaz, M.; Fazloli, R.; Gholami Sefidkouhi, M. A.

2017-01-01

In recent decades the human impacts on global warming and, its consequences, climate change, stirred up earth ecosystems balance and has created many problems all over the world. Unauthorized underground water removal, especially in arid and semi-arid regions of Iran, along with recent decade drought occurrences significantly lowered underground and surface water levels. To investigate the impacts of water removal from surrounding wells in Parishan Lake water level, during 1996 to 2009 interval, 8 buffer layers surrounding the lake were mapped in ArcGIS 9.3 environment. Each buffer layer wells and their total annual discharges were determined. Using SPSS 16 software, the regression equations between wells water levels and water discharges were computed. By employing Thiessen function and creating Thiessen network (TIN) around observation wells, decline of groundwater levels was evaluated. Finally regression equations between wells discharges and groundwater level declines were created. The findings showed that there are highly significant correlations (p ≤ 0.01), in all buffer layers, between water levels and wells discharges. Investigation of the observation wells surrounding lake showed that severe groundwater level declines has been started since the beginning of the first decade of the 21st century. Using satellite images in ArcGIS 9.3 environment it was confirmed that lake’s area has been reduced significantly. In conclusion, it is obvious that human interferences on lake’s natural ecosystem by digging unauthorized wells and removing underground water more than annual recharges significantly impacted surface and groundwater levels.

Comparison pesticide residue levels in the surface of Bertam River in Cameron Highlands, Pahang

International Nuclear Information System (INIS)

Haron, S. H.; Ismail, B. S.

2015-01-01

The presence of pesticide residues in the surface water of Bertam River in the agricultural areas of Cameron Highlands in Pahang, Malaysia was monitored from May to October 2014. The sampling sites were located at 10 sampling points along the Bertam River in the vegetable planting areas. The extraction method of the pesticide (organophosphate/pyrethroid) from the river samples used solid phase extraction followed by gas chromatography (with electron capture detector, ECD). Insecticides, cypermethrin and chlorpyrifos were found in the surface water of Bertam River. High level concentrations of those insecticides in the river were observed during the period from May to October 2014, a period which included both seasons (wet and dry seasons). The highest concentration of 2.66 µg/mL and 1.23 µg/mL of cypermethrin was observed during the wet and dry seasons respectively. This could be due to the frequent usage of the above-mentioned insecticides coupled with contamination that could have originated from the application sites. Meanwhile, the lowest concentration detected in the surface water was chlorpyrifos (0.11 µg/mL and 0.17 µg/mL) during the dry and wet seasons, respectively

Comparison pesticide residue levels in the surface of Bertam River in Cameron Highlands, Pahang

Energy Technology Data Exchange (ETDEWEB)

Haron, S. H., E-mail: ismail@ukm.edu.my; Ismail, B. S., E-mail: sthumaira@yahoo.com [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 UKM, Bangi, Selangor (Malaysia)

2015-09-25

The presence of pesticide residues in the surface water of Bertam River in the agricultural areas of Cameron Highlands in Pahang, Malaysia was monitored from May to October 2014. The sampling sites were located at 10 sampling points along the Bertam River in the vegetable planting areas. The extraction method of the pesticide (organophosphate/pyrethroid) from the river samples used solid phase extraction followed by gas chromatography (with electron capture detector, ECD). Insecticides, cypermethrin and chlorpyrifos were found in the surface water of Bertam River. High level concentrations of those insecticides in the river were observed during the period from May to October 2014, a period which included both seasons (wet and dry seasons). The highest concentration of 2.66 µg/mL and 1.23 µg/mL of cypermethrin was observed during the wet and dry seasons respectively. This could be due to the frequent usage of the above-mentioned insecticides coupled with contamination that could have originated from the application sites. Meanwhile, the lowest concentration detected in the surface water was chlorpyrifos (0.11 µg/mL and 0.17 µg/mL) during the dry and wet seasons, respectively.

Concave omnidirectional imaging device for cylindrical object based on catadioptric panoramic imaging

Science.gov (United States)

Wu, Xiaojun; Wu, Yumei; Wen, Peizhi

2018-03-01

To obtain information on the outer surface of a cylinder object, we propose a catadioptric panoramic imaging system based on the principle of uniform spatial resolution for vertical scenes. First, the influence of the projection-equation coefficients on the spatial resolution and astigmatism of the panoramic system are discussed, respectively. Through parameter optimization, we obtain the appropriate coefficients for the projection equation, and so the imaging quality of the entire imaging system can reach an optimum value. Finally, the system projection equation is calibrated, and an undistorted rectangular panoramic image is obtained using the cylindrical-surface projection expansion method. The proposed 360-deg panoramic-imaging device overcomes the shortcomings of existing surface panoramic-imaging methods, and it has the advantages of low cost, simple structure, high imaging quality, and small distortion, etc. The experimental results show the effectiveness of the proposed method.

Site characterization field manual for near surface geologic disposal of low-level radioactive waste

International Nuclear Information System (INIS)

McCray, J.G.; Nowatzki, E.A.

1985-01-01

This field manual has been developed to aid states and regions to do a detailed characterization of a proposed near-surface low-level waste disposal site. The field manual is directed at planners, staff personnel and experts in one discipline to acquaint them with the requirements of other disciplines involved in site characterization. While it can provide a good review, it is not designed to tell experts how to do their job within their own discipline

Design and operational considerations of United States commercial nea-surface low-level radioactive waste disposal facilities

International Nuclear Information System (INIS)

Birk, Sandra M.

1997-01-01

Low-level radioactive waste disposal standards and techniques in the United States have evolved significantly since the early 1960's. Six commercial LLW disposal facilities(Barnwell, Richland, Ward Valley, Sierra Blanca, Wake County and Boyd County) operated and proposed between 1962 and 1997. This report summarizes each site's design and operational considerations for near-surface disposal of low-level radioactive waste. These new standards and mitigating efforts at closed facilities (Sheffield, Maxey Flats, Beatty and West Valley) have helped to ensure that the public has been safely protected from LLW. 15 refs

Sub-nanoscale surface ruggedness provides a water-tight seal for exposed regions in soluble protein structure.

Directory of Open Access Journals (Sweden)

Erica Schulz

2010-09-01

Full Text Available Soluble proteins must maintain backbone hydrogen bonds (BHBs water-tight to ensure structural integrity. This protection is often achieved by burying the BHBs or wrapping them through intermolecular associations. On the other hand, water has low coordination resilience, with loss of hydrogen-bonding partnerships carrying significant thermodynamic cost. Thus, a core problem in structural biology is whether natural design actually exploits the water coordination stiffness to seal the backbone in regions that are exposed to the solvent. This work explores the molecular design features that make this type of seal operative, focusing on the side-chain arrangements that shield the protein backbone. We show that an efficient sealing is achieved by adapting the sub-nanoscale surface topography to the stringency of water coordination: an exposed BHB may be kept dry if the local concave curvature is small enough to impede formation of the coordination shell of a penetrating water molecule. Examination of an exhaustive database of uncomplexed proteins reveals that exposed BHBs invariably occur within such sub-nanoscale cavities in native folds, while this level of local ruggedness is absent in other regions. By contrast, BHB exposure in misfolded proteins occurs with larger local curvature promoting backbone hydration and consequently, structure disruption. These findings unravel physical constraints fitting a spatially dependent least-action for water coordination, introduce a molecular design concept, and herald the advent of water-tight peptide-based materials with sufficient backbone exposure to remain flexible.

Substrate Curvature Regulates Cell Migration -A Computational Study

Science.gov (United States)

He, Xiuxiu; Jiang, Yi

Cell migration in host microenvironment is essential to cancer etiology, progression and metastasis. Cellular processes of adhesion, cytoskeletal polymerization, contraction, and matrix remodeling act in concert to regulate cell migration, while local extracellular matrix architecture modulate these processes. In this work we study how stromal microenvironment with native and cell-derived curvature at micron-meter scale regulate cell motility pattern. We developed a 3D model of single cell migration on a curved substrate. Mathematical analysis of cell morphological adaption to the cell-substrate interface shows that cell migration on convex surfaces deforms more than on concave surfaces. Both analytical and simulation results show that curved surfaces regulate the cell motile force for cell's protruding front through force balance with focal adhesion and cell contraction. We also found that cell migration on concave substrates is more persistent. These results offer a novel biomechanical explanation to substrate curvature regulation of cell migration. NIH 1U01CA143069.

Estimation of surface-level PM2.5 concentration using aerosol optical thickness through aerosol type analysis method

Science.gov (United States)

Chen, Qi-Xiang; Yuan, Yuan; Huang, Xing; Jiang, Yan-Qiu; Tan, He-Ping

2017-06-01

Surface-level particulate matter is closely related to column aerosol optical thickness (AOT). Previous researches have successfully used column AOT and different meteorological parameters to estimate surface-level PM concentration. In this study, the performance of a selected linear model that estimates surface-level PM2.5 concentration was evaluated following the aerosol type analysis method (ATAM) for the first time. We utilized 443 daily average data for Xuzhou, Jiangsu province, collected using Aerosol Robotic Network (AERONET) during the period October 2013 to April 2016. Several parameters including atmospheric boundary layer height (BLH), relative humidity (RH), and effective radius of the aerosol size distribution (Ref) were used to assess the relationship between the column AOT and PM2.5 concentration. By including the BLH, ambient RH, and effective radius, the correlation (R2) increased from 0.084 to 0.250 at Xuzhou, and with the use of ATAM, the correlation increased further to 0.335. To compare the results, 450 daily average data for Beijing, pertaining to the same period, were utilized. The study found that model correlations improved by varying degrees in different seasons and at different sites following ATAM. The average urban industry (UI) aerosol ratios at Xuzhou and Beijing were 0.792 and 0.451, respectively, demonstrating poorer air conditions at Xuzhou. PM2.5 estimation at Xuzhou showed lower correlation (R2 = 0.335) compared to Beijing (R2 = 0.407), and the increase of R2 at Xuzhou and Beijing site following use of ATAM were 33.8% and 12.4%, respectively.

Quantifying the Uncertainty in High Spatial and Temporal Resolution Synthetic Land Surface Reflectance at Pixel Level Using Ground-Based Measurements

Science.gov (United States)

Kong, J.; Ryu, Y.

2017-12-01

Algorithms for fusing high temporal frequency and high spatial resolution satellite images are widely used to develop dense time-series land surface observations. While many studies have revealed that the synthesized frequent high spatial resolution images could be successfully applied in vegetation mapping and monitoring, validation and correction of fused images have not been focused than its importance. To evaluate the precision of fused image in pixel level, in-situ reflectance measurements which could account for the pixel-level heterogeneity are necessary. In this study, the synthetic images of land surface reflectance were predicted by the coarse high-frequency images acquired from MODIS and high spatial resolution images from Landsat-8 OLI using the Flexible Spatiotemporal Data Fusion (FSDAF). Ground-based reflectance was measured by JAZ Spectrometer (Ocean Optics, Dunedin, FL, USA) on rice paddy during five main growth stages in Cheorwon-gun, Republic of Korea, where the landscape heterogeneity changes through the growing season. After analyzing the spatial heterogeneity and seasonal variation of land surface reflectance based on the ground measurements, the uncertainties of the fused images were quantified at pixel level. Finally, this relationship was applied to correct the fused reflectance images and build the seasonal time series of rice paddy surface reflectance. This dataset could be significant for rice planting area extraction, phenological stages detection, and variables estimation.

A novel model to assess the efficacy of steam surface pasteurization of cooked surimi gels inoculated with realistic levels of Listeria innocua.

Science.gov (United States)

Skåra, Torstein; Valdramidis, Vasilis P; Rosnes, Jan Thomas; Noriega, Estefanía; Van Impe, Jan F M

2014-12-01

Steam surface pasteurization is a promising decontamination technology for reducing pathogenic bacteria in different stages of food production. The effect of the artificial inoculation type and initial microbial load, however, has not been thoroughly assessed in the context of inactivation studies. In order to optimize the efficacy of the technology, the aim of this study was to design and validate a model system for steam surface pasteurization, assessing different inoculation methods and realistic microbial levels. More specifically, the response of Listeria innocua, a surrogate organism of Listeria monocytogenes, on a model fish product, and the effect of different inoculation levels following treatments with a steam surface pasteurization system was investigated. The variation in the resulting inoculation level on the samples was too large (77%) for the contact inoculation procedure to be further considered. In contrast, the variation of a drop inoculation procedure was 17%. Inoculation with high levels showed a rapid 1-2 log decrease after 3-5 s, and then no further inactivation beyond 20 s. A low level inoculation study was performed by analysing the treated samples using a novel contact plating approach, which can be performed without sample homogenization and dilution. Using logistic regression, results from this method were used to model the binary responses of Listeria on surfaces with realistic inoculation levels. According to this model, a treatment time of 23 s will result in a 1 log reduction (for P = 0.1). Copyright © 2014 Elsevier Ltd. All rights reserved.

Fermi level on hydrogen terminated diamond surfaces

Czech Academy of Sciences Publication Activity Database

Rezek, Bohuslav; Saurer, C.; Nebel, C. E.; Stutzmann, M.; Ristein, J.; Ley, L.; Snidero, E.; Bergonzo, P.

2003-01-01

Roč. 82, č. 14 (2003), s. 2266-2268 ISSN 0003-6951 EU Projects: European Commission(XE) HPRN-CT-1999-00139 Grant - others:DFC(DE) NE524-2 Institutional research plan: CEZ:AV0Z1010914 Keywords : atomic force microscope (AFM) * Kelvin probe experiments * diamond surface Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.049, year: 2003

Analysing the impact of reflectance distributions and well geometries on vertical surface daylight levels in atria for overcast skies

Energy Technology Data Exchange (ETDEWEB)

Du, Jiangtao; Sharples, Steve [School of Architecture, University of Sheffield, Crookesmoor Building, Conduit Road, Sheffield S10 1FL (United Kingdom)

2010-07-15

This study investigated the impacts of different diffuse reflectance distributions and well geometries on vertical daylight factors and vertical internally reflected components in atria. Two forms of reflectance distribution patterns of wall surface were examined: horizontal and vertical reflectance band variation. The square atrium models studied have a broader WI range of 0.25-2.0, which represent shallow, medium and high atria. Radiance, a powerful package based on backward ray tracing technique, was used for the simulations of vertical daylight levels. The results show that different reflectance distributions of square atrium walls do have an impact on the vertical daylight factors and vertical internally reflected components under overcast sky condition. The impact relates to the orientation of the band with different reflectance distributions on the wall. Compared with the vertical band surface, the horizontal band surface has a much more complicated effect. The horizontal distributions of the reflectances significantly affects the vertical daylight levels at the locations more than 30% atrium height on the wall. For an atrium with a height more than 1/2 the width, the effect tends to increase with the increasing well index. The vertical distributions of the reflectance, nevertheless, do not substantially take effect on the vertical daylight levels in atria except for some special reflectance distribution patterns. (author)

Surface-type repository for low and intermediate level radioactive waste in the Republic of Croatia

International Nuclear Information System (INIS)

Kucar-Dragicevic, S.; Zarkovic, V.; Subasic, D.

1995-01-01

The low-level intermediate-level (LL/IL) radioactive waste repository siting and construction project is one of the activities related to establishing the rad waste management system in the Republic of Croatia. The repository project design is one in an array of project activities which also include the site selection procedure and public attitude issues. The prepared design documentation gives technical, safety and financial background relevant for making a final decision on the waste disposal type, and it includes the technological, mechanical, civil and financial documentation on the preliminary/basic design level. During the last few years, the preliminary design has been prepared and safety assessment conducted for the tunnel-type LL/IL rad waste repository. As the surface-type repository is one of alternatives for final disposal the design documentation for that repository type was prepared during 1994. (author)

A method for the experimental determination of surface photoemission core-level shifts for 3d transition metals

NARCIS (Netherlands)

Shamsutdinov, N.R.; Sloof, W.G.; Böttger, A.J.

2005-01-01

A method is presented to determine the photoelectron surface core-level shift (SCLS) of 3d transition metals using x-ray photoelectron spectroscopy. The experimental difficulties arising from the relatively large broadening of photoemission lines in the 3d transition series can be overcome by the

Influence of surface states on deep level transient spectroscopy in AlGaN/GaN heterostructure

International Nuclear Information System (INIS)

Zhu Qing; Ma Xiao-Hua; Chen Wei-Wei; Hou Bin; Zhu Jie-Jie; Zhang Meng; Chen Li-Xiang; Cao Yan-Rong; Hao Yue

2016-01-01

Deep level transient spectroscopy (DLTS) as a method to investigate deep traps in AlGaN/GaN heterostructure or high electron mobility transistors (HEMTs) has been widely utilized. The DLTS measurements under different bias conditions are carried out in this paper. Two hole-like traps with active energies of E v + 0.47 eV, and E v + 0.10 eV are observed, which are related to surface states. The electron traps with active energies of E c − 0.56 eV are located in the channel, those with E c − 0.33 eV and E c − 0.88 eV are located in the AlGaN layer. The presence of surface states has a strong influence on the detection of electron traps, especially when the electron traps are low in density. The DLTS signal peak height of the electron trap is reduced and even disappears due to the presence of plentiful surface state. (paper)

Soils Developed on Geomorphic Surfaces in the Mountain Region of the State of Rio de Janeiro

Directory of Open Access Journals (Sweden)

Ademir Fontana

2018-01-01

Full Text Available ABSTRACT: The evaluation of soils in representative landscapes constitutes an opportunity to evaluate spatial distribution, discuss formation processes, and apply this knowledge to land use and management. In this sense, from the perspective of an environmentally diversified region, the aim of the present study is to evaluate the occurrence and understand the formation of soils in different geomorphic surfaces of a landscape from a mountain region in the state of Rio de Janeiro. The study was developed in the Pito Aceso microbasin in the municipality of Bom Jardim, composed of narrow valleys and a rugged mountain domain, with elevation between 640 and 1,270 m. In a representative landscape, the geomorphic surfaces were obtained from the slope segments and flow lines. On the geomorphic surfaces, soil profiles were described by their morphological properties, collected, and analyzed to describe the chemical and physical properties of each horizon. Geomorphological aspects and possible variations of the parent material directly affected pedogenesis and led to distinct soil classes in the landscape. Variation in the geomorphic surfaces directs the processes for soil formation under current conditions, as well as the preservation of polygenetic soils. Soils of lower development and with greater participation of the exchangeable cations were identified at the summit (talus deposit (Neossolo Litólico and Cambissolo Húmico and toeslope (colluvial-alluvial (Neossolo Flúvico, whereas more developed soils with lower nutrient content occur in the concave (Argissolos Vermelho and Amarelo and convex (Latossolo Amarelo backslope, except for the Argissolo Vermelho-Amarelo in the shoulder, which had high exchangeable cations contents.

Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise

Science.gov (United States)

Krauss, Ken W.; Cormier, Nicole; Osland, Michael J.; Kirwan, Matthew L.; Stagg, Camille L.; Nestlerode, Janet A.; Russell, Marc J.; From, Andrew; Spivak, Amanda C.; Dantin, Darrin D.; Harvey, James E.; Almario, Alejandro E.

2017-01-01

Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove wetlands over a 25 year developmental gradient. All created mangrove wetlands were exceeding current relative sea-level rise rates (2.6 mm yr−1), with surface elevation change of 4.2–11.0 mm yr−1 compared with 1.5–7.2 mm yr−1 for nearby reference mangroves. While mangrove wetlands store C persistently in roots/soils, storage capacity is most valuable if maintained with future sea-level rise. Through empirical modeling, we discovered that properly designed creation projects may not only yield enhanced C storage, but also can facilitate wetland persistence perennially under current rates of sea-level rise and, for most sites, for over a century with projected medium accelerations in sea-level rise (IPCC RCP 6.0). Only the fastest projected accelerations in sea-level rise (IPCC RCP 8.5) led to widespread submergence and potential loss of stored C for created mangrove wetlands before 2100.

Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise.

Science.gov (United States)

Krauss, Ken W; Cormier, Nicole; Osland, Michael J; Kirwan, Matthew L; Stagg, Camille L; Nestlerode, Janet A; Russell, Marc J; From, Andrew S; Spivak, Amanda C; Dantin, Darrin D; Harvey, James E; Almario, Alejandro E

2017-04-21

Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove wetlands over a 25 year developmental gradient. All created mangrove wetlands were exceeding current relative sea-level rise rates (2.6 mm yr -1 ), with surface elevation change of 4.2-11.0 mm yr -1 compared with 1.5-7.2 mm yr -1 for nearby reference mangroves. While mangrove wetlands store C persistently in roots/soils, storage capacity is most valuable if maintained with future sea-level rise. Through empirical modeling, we discovered that properly designed creation projects may not only yield enhanced C storage, but also can facilitate wetland persistence perennially under current rates of sea-level rise and, for most sites, for over a century with projected medium accelerations in sea-level rise (IPCC RCP 6.0). Only the fastest projected accelerations in sea-level rise (IPCC RCP 8.5) led to widespread submergence and potential loss of stored C for created mangrove wetlands before 2100.

Surface Functionalization of g-C 3 N 4 : Molecular-Level Design of Noble-Metal-Free Hydrogen Evolution Photocatalysts

KAUST Repository

Chen, Yin; Lin, Bin; Yu, Weili; Yang, Yong; Bashir, Shahid M.; Wang, Hong; Takanabe, Kazuhiro; Idriss, Hicham; Basset, Jean-Marie

2015-01-01

A stable noble-metal-free hydrogen evolution photocatalyst based on graphite carbon nitride (g-C3N4) was developed by a molecular-level design strategy. Surface functionalization was successfully conducted to introduce a single nickel active site

Surface radiological investigations of Trench 6 and low-level waste Line Leak Site 7.4b at the Oak Ridge National Laboratory, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Uziel, M.S.; Tiner, P.F.; Williams, J.K.

1991-08-01

A surface radiological investigation of Trench 6 and low-level radioactive waste (LLW) Line Leak Site 7.4b was conducted in July and August 1989 and January 1990 by the Measurement Applications and Development Group, Oak Ridge National Laboratory. The purposes of this survey were (1) to determine the presence, nature, and extent of surface radiological contamination and (2) to recommend interim corrective action to limit human exposures to radioactivity and minimize the potential for contaminant dispersion. Highest surface gamma levels encountered during the survey (39 mR/h) were found just south of the asphalt covering LLW Line Leak Site 7.4b. Elevated surface gamma levels (measuring 28 to 560 μR/h) extended from this area to a width of 100 ft, westward 250 ft, and beyond the survey boundary. Beta-gamma levels up to 17 mrad/h measured on contact with the trunks of trees growing in the area southwest of Trench 6 suggest that three roots are reaching contamination deep within the ground. Since no gamma activity is associated with the trees or their leaves, the elevated beta levels are probably due to the uptake of residual 90 Sr originating from the documented seepage at the Trench 6/Leak Site 7.4b area. Beta activity present in the leaf litter and surface soil indicate that decaying leaves are depositing measurable contaminants on the ground surface. Recommendations for corrective actions are included. 7 refs., 20 figs., 3 tabs

A Molecular-Level Account of the Antigenic Hantaviral Surface

Directory of Open Access Journals (Sweden)

Sai Li

2016-05-01

Full Text Available Hantaviruses, a geographically diverse group of zoonotic pathogens, initiate cell infection through the concerted action of Gn and Gc viral surface glycoproteins. Here, we describe the high-resolution crystal structure of the antigenic ectodomain of Gn from Puumala hantavirus (PUUV, a causative agent of hemorrhagic fever with renal syndrome. Fitting of PUUV Gn into an electron cryomicroscopy reconstruction of intact Gn-Gc spike complexes from the closely related but non-pathogenic Tula hantavirus localized Gn tetramers to the membrane-distal surface of the virion. The accuracy of the fitting was corroborated by epitope mapping and genetic analysis of available PUUV sequences. Interestingly, Gn exhibits greater non-synonymous sequence diversity than the less accessible Gc, supporting a role of the host humoral immune response in exerting selective pressure on the virus surface. The fold of PUUV Gn is likely to be widely conserved across hantaviruses.

PHOTOMETRIC STEREO SHAPE-AND-ALBEDO-FROM-SHADING FOR PIXEL-LEVEL RESOLUTION LUNAR SURFACE RECONSTRUCTION

Directory of Open Access Journals (Sweden)

W. C. Liu

2017-07-01

Full Text Available Shape and Albedo from Shading (SAfS techniques recover pixel-wise surface details based on the relationship between terrain slopes, illumination and imaging geometry, and the energy response (i.e., image intensity captured by the sensing system. Multiple images with different illumination geometries (i.e., photometric stereo can provide better SAfS surface reconstruction due to the increase in observations. Photometric stereo SAfS is suitable for detailed surface reconstruction of the Moon and other extra-terrestrial bodies due to the availability of photometric stereo and the less complex surface reflecting properties (i.e., albedo of the target bodies as compared to the Earth. Considering only one photometric stereo pair (i.e., two images, pixel-variant albedo is still a major obstacle to satisfactory reconstruction and it needs to be regulated by the SAfS algorithm. The illumination directional difference between the two images also becomes an important factor affecting the reconstruction quality. This paper presents a photometric stereo SAfS algorithm for pixel-level resolution lunar surface reconstruction. The algorithm includes a hierarchical optimization architecture for handling pixel-variant albedo and improving performance. With the use of Lunar Reconnaissance Orbiter Camera - Narrow Angle Camera (LROC NAC photometric stereo images, the reconstructed topography (i.e., the DEM is compared with the DEM produced independently by photogrammetric methods. This paper also addresses the effect of illumination directional difference in between one photometric stereo pair on the reconstruction quality of the proposed algorithm by both mathematical and experimental analysis. In this case, LROC NAC images under multiple illumination directions are utilized by the proposed algorithm for experimental comparison. The mathematical derivation suggests an illumination azimuthal difference of 90 degrees between two images is recommended to achieve

Beyond level planarity

NARCIS (Netherlands)

Angelini, P.; Da Lozzo, G.; Di Battista, G.; Frati, F.; Patrignani, M.; Rutter, I.; Hu, Y.; Nöllenburg, M.

2016-01-01

In this paper we settle the computational complexity of two open problems related to the extension of the notion of level planarity to surfaces different from the plane. Namely, we show that the problems of testing the existence of a level embedding of a level graph on the surface of the rolling

The SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) Product

Science.gov (United States)

Reichle, Rolf; Crow, Wade; Koster, Randal; Kimball, John

2010-01-01

The Soil Moisture Active and Passive (SMAP) mission is being developed by NASA for launch in 2013 as one of four first-tier missions recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space in 2007. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, the high resolution soil moisture mapping provided by SMAP has practical applications in weather and seasonal climate prediction, agriculture, human health, drought and flood decision support. In this paper we describe the assimilation of SMAP observations for the generation of the planned SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) product. The SMAP mission makes simultaneous active (radar) and passive (radiometer) measurements in the 1.26-1.43 GHz range (L-band) from a sun-synchronous low-earth orbit. Measurements will be obtained across a 1000 km wide swath using conical scanning at a constant incidence angle (40 deg). The radar resolution varies from 1-3 km over the outer 70% of the swath to about 30 km near the center of the swath. The radiometer resolution is 40 km across the entire swath. The radiometer measurements will allow high-accuracy but coarse resolution (40 km) measurements. The radar measurements will add significantly higher resolution information. The radar is however very sensitive to surface roughness and vegetation structure. The combination of the two measurements allows optimal blending of the advantages of each instrument. SMAP directly observes only surface soil moisture (in the top 5 cm of the soil column). Several of the key applications targeted by SMAP, however, require knowledge of root zone soil moisture (approximately top 1 m of the soil column), which is not directly measured by SMAP. The foremost objective of the SMAP L4_SM product is to fill this gap and provide estimates of root zone soil moisture

Structural origin of Si-2p core-level shifts from Si(100)-c[4x2] surface: A spectral x-ray photoelectron diffraction study

Energy Technology Data Exchange (ETDEWEB)

Chen, X.; Tonner, B.P. [Univ. of Wisconsin, Milwaukee, WI (United States); Denlinger, J. [Univ. of Wisconsin, Milwaukee, WI (United States)][Ernest Orlando Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

The authors have performed angle-resolved x-ray photoelectron diffraction (XPD) from a Si(100)-c(4x2) surface to study the structural origin of Si-2p core-level shifts. In the experiment, the highly resolved surface Si-2p core-level spectra were measured as a fine grid of hemisphere and photon energies, using the SpectroMicroscopy Facility {open_quotes}ultraESCA{close_quotes} instrument. By carefully decomposing the spectra into several surface peaks, the authors are able to obtain surface-atom resolved XPD patterns. Using a multiple scattering analysis, they derived a detailed atomic model for the Si(100)-c(4x2) surface. In this model, the asymmetric dimers were found tilted by 11.5 plus/minus 2.0 degrees with bond length of 2.32 plus/minus 0.05{angstrom}. By matching model XPD patterns to experiment, the authors can identify which atoms in the reconstructed surface are responsible for specific photoemission lines in the 2p spectrum.

Statistical characterization of global Sea Surface Salinity for SMOS level 3 and 4 products

Science.gov (United States)

Gourrion, J.; Aretxabaleta, A. L.; Ballabrera, J.; Mourre, B.

2009-04-01

The Soil Moisture and Ocean Salinity (SMOS) mission of the European Space Agency will soon provide sea surface salinity (SSS) estimates to the scientific community. Because of the numerous geophysical contamination sources and the instrument complexity, the salinity products will have a low signal to noise ratio at level 2 (individual estimates??) that is expected to increase up to mission requirements (0.1 psu) at level 3 (global maps with regular distribution) after spatio-temporal accumulation of the observations. Geostatistical methods such as Optimal Interpolation are being implemented at the level 3/4 production centers to operate this noise reduction step. The methodologies require auxiliary information about SSS statistics that, under Gaussian assumption, consist in the mean field and the covariance of the departures from it. The present study is a contribution to the definition of the best estimates for mean field and covariances to be used in the near-future SMOS level 3 and 4 products. We use complementary information from sparse in-situ observations and imperfect outputs from state-of-art model simulations. Various estimates of the mean field are compared. An alternative is the use of a SSS climatology such as the one provided by the World Ocean Atlas 2005. An historical SSS dataset from the World Ocean Database 2005 is reanalyzed and combined with the recent global observations obtained by the Array for Real-Time Geostrophic Oceanography (ARGO). Regional tendencies in the long-term temporal evolution of the near-surface ocean salinity are evident, suggesting that the use of a SSS climatology to describe the current mean field may introduce biases of magnitude similar to the precision goal. Consequently, a recent SSS dataset may be preferred to define the mean field needed for SMOS level 3 and 4 production. The in-situ observation network allows a global mapping of the low frequency component of the variability, i.e. decadal, interannual and seasonal

Programmable System-on-Chip (PSoC) Embedded Readout Designs for Liquid Helium Level Sensors.

Science.gov (United States)

Parasakthi, C; Gireesan, K; Usha Rani, R; Sheela, O K; Janawadkar, M P

2014-08-01

This article reports the development of programmable system-on-chip (PSoC)-based embedded readout designs for liquid helium level sensors using resistive liquid vapor discriminators. The system has been built for the measurement of liquid helium level in a concave-bottomed, helmet-shaped, fiber-reinforced plastic cryostat for magnetoencephalography. This design incorporates three carbon resistors as cost-effective sensors, which are mounted at desired heights inside the cryostat and were used to infer the liquid helium level by measuring their temperature-dependent resistance. Localized electrical heating of the carbon resistors was used to discriminate whether the resistor is immersed in liquid helium or its vapor by exploiting the difference in the heat transfer rates in the two environments. This report describes a single PSoC chip for the design and development of a constant current source to drive the three carbon resistors, a multiplexer to route the sensor outputs to the analog-to-digital converter (ADC), a buffer to avoid loading of the sensors, an ADC for digitizing the data, and a display using liquid crystal display cum light-emitting diode modules. The level sensor readout designed with a single PSoC chip enables cost-effective and reliable measurement system design. © 2014 Society for Laboratory Automation and Screening.

Photographic monitoring of soiling and decay of roadside walls in central Oxford, England

Science.gov (United States)

Thornbush, Mary J.; Viles, Heather A.

2008-12-01

As part of the Environmental Monitoring of Integrated Transport Strategies (EMITS) project, which examined the impact of the Oxford Transport Strategy (OTS) on the soiling and decay of buildings and structures in central Oxford, England, a simple photographic survey of a sample of roadside walls was carried out in 1997, with re-surveys in 1999 and 2003. Thirty photographs were taken each time, covering an area of stonework approximately 30 × 30 cm in dimensions at 1-1.3 m above pavement level. The resulting images have been used to investigate, both qualitatively as well as quantitatively, the progression of soiling and decay. Comparison of images by eye reveals a number of minor changes in soiling and decay patterns, but generally indicates stability except at one site where dramatic, superficial damage occurred over 2 years. Quantitative analysis of decay features (concavities resulting from surface blistering, flaking, and scaling), using simple techniques in Adobe Photoshop, shows variable pixel-based size proportions of concavities across 6 years of survey. Colour images (in Lab Color) generally have a reduced proportion of pixels, representing decay features in comparison to black and white (Grayscale) images. The study conveys that colour images provide more information both for general observations of soiling and decay patterns and for segmentation of decay-produced concavities. The study indicates that simple repeat photography can reveal useful information about changing patterns of both soiling and decay, although unavoidable variation in external lighting conditions between re-surveys is a factor limiting the accuracy of change detection.

An acceleration of the characteristics by a space-angle two-level method using surface discontinuity factors

Energy Technology Data Exchange (ETDEWEB)

Grassi, G. [Commissariat a l' Energie Atomique, CEA de Saclay, DM2S/SERMA/LENR, 91191, Gif-sur-Yvette (France)

2006-07-01

We present a non-linear space-angle two-level acceleration scheme for the method of the characteristics (MOC). To the fine level on which the MOC transport calculation is performed, we associate a more coarsely discretized phase space in which a low-order problem is solved as an acceleration step. Cross sections on the coarse level are obtained by a flux-volume homogenisation technique, which entails the non-linearity of the acceleration. Discontinuity factors per surface are introduced as additional degrees of freedom on the coarse level in order to ensure the equivalence of the heterogeneous and the homogenised problem. After each fine transport iteration, a low-order transport problem is iteratively solved on the homogenised grid. The solution of this problem is then used to correct the angular moments of the flux resulting from the previous free transport sweep. Numerical tests for a given benchmark have been performed. Results are discussed. (authors)

An acceleration of the characteristics by a space-angle two-level method using surface discontinuity factors

International Nuclear Information System (INIS)

Grassi, G.

2006-01-01

We present a non-linear space-angle two-level acceleration scheme for the method of the characteristics (MOC). To the fine level on which the MOC transport calculation is performed, we associate a more coarsely discretized phase space in which a low-order problem is solved as an acceleration step. Cross sections on the coarse level are obtained by a flux-volume homogenisation technique, which entails the non-linearity of the acceleration. Discontinuity factors per surface are introduced as additional degrees of freedom on the coarse level in order to ensure the equivalence of the heterogeneous and the homogenised problem. After each fine transport iteration, a low-order transport problem is iteratively solved on the homogenised grid. The solution of this problem is then used to correct the angular moments of the flux resulting from the previous free transport sweep. Numerical tests for a given benchmark have been performed. Results are discussed. (authors)

Evaluation of pressure transducers to measure surface level in the waste storage tanks

International Nuclear Information System (INIS)

Peters, T.J.; Colson, J.B.

1994-06-01

This report describes the results of tests conducted at the Pacific Northwest Laboratory (PNL) to determine if pressure transducers can be used to measure the surface level in the waste tanks. A survey was first conducted to evaluate which, if any, commercially available pressure transducers were available that could meet the requirements for use in the waste tanks. More than 35 companies were contacted to determine if they manufactured a pressure transducer that could be used in the 101-SY waste tank. The three basic requirements for a pressure transducer for this application were that they were radiation-hardened, could withstand a caustic environment, and were certified to be intrinsically safe. No manufacturer was able to meet all three of these requirements with a commercially available product. Seven companies were able to meet the requirements for being radiation-hardened and being able to withstand the caustic environment. However, only two of the nine companies were willing to supply a pressure transducer for laboratory testing. The two pressure transducers that were tested in this program were the VEGA D36-38 from HiTech Technologies, Inc., and the KP-1911-A from Kaman Instrumentation Corporation. Pressure transducers operate on the principle that the pressure at the location of a sensor increases directly with the depth of the liquid above it. A liquid is required in order for these devices to operate. For these tests, water was first used to determine the ideal operation of the devices, then the devices were placed in a 101-SY waste tank simulant. The simulant had a specific gravity of 1.96 and had the consistency similar to the convective layer in the 101-SY waste tank. In order to determine the surface level with pressure transducers, the density of the material needs to be known

Curvature recognition and force generation in phagocytosis

Directory of Open Access Journals (Sweden)

Prassler Jana

2010-12-01

Full Text Available Abstract Background The uptake of particles by actin-powered invagination of the plasma membrane is common to protozoa and to phagocytes involved in the immune response of higher organisms. The question addressed here is how a phagocyte may use geometric cues to optimize force generation for the uptake of a particle. We survey mechanisms that enable a phagocyte to remodel actin organization in response to particles of complex shape. Results Using particles that consist of two lobes separated by a neck, we found that Dictyostelium cells transmit signals concerning the curvature of a surface to the actin system underlying the plasma membrane. Force applied to a concave region can divide a particle in two, allowing engulfment of the portion first encountered. The phagosome membrane that is bent around the concave region is marked by a protein containing an inverse Bin-Amphiphysin-Rvs (I-BAR domain in combination with an Src homology (SH3 domain, similar to mammalian insulin receptor tyrosine kinase substrate p53. Regulatory proteins enable the phagocyte to switch activities within seconds in response to particle shape. Ras, an inducer of actin polymerization, is activated along the cup surface. Coronin, which limits the lifetime of actin structures, is reversibly recruited to the cup, reflecting a program of actin depolymerization. The various forms of myosin-I are candidate motor proteins for force generation in particle uptake, whereas myosin-II is engaged only in retracting a phagocytic cup after a switch to particle release. Thus, the constriction of a phagocytic cup differs from the contraction of a cleavage furrow in mitosis. Conclusions Phagocytes scan a particle surface for convex and concave regions. By modulating the spatiotemporal pattern of actin organization, they are capable of switching between different modes of interaction with a particle, either arresting at a concave region and applying force in an attempt to sever the particle

Diffusion induced flow on a wedge-shaped obstacle

International Nuclear Information System (INIS)

Zagumennyi, Ia V; Dimitrieva, N F

2016-01-01

In this paper the problem of evolution of diffusion induced flow on a wedge-shaped obstacle is analyzed numerically. The governing set of fundamental equations is solved using original solvers from the open source OpenFOAM package on supercomputer facilities. Due to breaking of naturally existing diffusion flux of a stratifying agent by the impermeable surface of the wedge a complex multi-level vortex system of compensatory fluid motions is formed around the obstacle. Sharp edges of the obstacle generate extended high-gradient horizontal interfaces which are clearly observed in laboratory experiments by high-resolution Schlieren visualization. Formation of an intensive pressure depression zone in front of the leading vertex of the wedge is responsible for generation of propulsive force resulting in a self-displacement of the obstacle along the neutral buoyancy horizon in a stably stratified environment. The size of the pressure deficiency area near the sharp vertex of a concave wedge is about twice that for a convex one. This demonstrates a more intensive propulsion mechanism in case of the concave wedge and, accordingly, a higher velocity of its self-movement in a continuously stratified medium. (paper)

Sensitivity analysis for near-surface disposal in argillaceous media using NAMMU-HYROCOIN Level 3-Test case 1

International Nuclear Information System (INIS)

Miller, D.R.; Paige, R.W.

1988-07-01

HYDROCOIN is an international project for comparing groundwater flow models and modelling strategies. Level 3 of the project concerns the application of groundwater flow models to repository performance assessment with emphasis on the treatment of sensitivity and uncertainty in models and data. Level 3, test case 1 concerns sensitivity analysis of the groundwater flow around a radioactive waste repository situated in a near surface argillaceous formation. Work on this test case has been carried out by Harwell and will be reported in full in the near future. This report presents the results obtained using the computer program NAMMU. (author)

Heat transfer from two-side heated helical channels

International Nuclear Information System (INIS)

Shimonis, V.; Ragaishis, V.; Poshkas, P.

1995-01-01

Experimental results are presented on the heat transfer from two-side heated helical channels to gas (air) flows. The study covered six configurations and wide ranges of geometrical (D/h=5.5 to 84.2) and performance (Re=10 3 to 2*10 5 ) parameters. Under the influence of Re and of the channel curvature, the heat transfer from both the convex and the concave surfaces for two-side heating (q w1 ≅ q w2 ) is augmented by 20-30% over one-side heating. Improved relations to predict the critical values of Reynolds Re cr1 and Re cr2 are suggested. They enable more exact predictions of the heat transfer from convex surface in transient flows for one-side heating. The relation for annular channels is suggested for the turbulent heat transfer from the convex and concave surfaces of two-side heated helical channels. It can be adapted by introducing earlier expresions for one-side heated helical channels. (author). 6 refs., 2 tabs., 3 figs

Pricing of Water Resources With Depletable Externality: The Effects of Pollution Charges

Science.gov (United States)

Kitabatake, Yoshifusa

1990-04-01

With an abstraction of a real-world situation, the paper views water resources as a depletable capital asset which yields a stream of services such as water supply and the assimilation of pollution discharge. The concept of the concave or convex water resource depletion function is then introduced and applied to a general two-sector, three-factor model. The main theoretical contribution is to prove that when the water resource depletion function is a concave rather than a convex function of pollution, it is more likely that gross regional income will increase with a higher pollution charge policy. The concavity of the function is meant to imply that with an increase in pollution released, the ability of supplying water at a certain minimum quality level diminishes faster and faster. A numerical example is also provided.

Reduction Expansion Synthesis as Strategy to Control Nitrogen Doping Level and Surface Area in Graphene

Directory of Open Access Journals (Sweden)

Russell Canty

2015-10-01

Full Text Available Graphene sheets doped with nitrogen were produced by the reduction-expansion (RES method utilizing graphite oxide (GO and urea as precursor materials. The simultaneous graphene generation and nitrogen insertion reactions are based on the fact that urea decomposes upon heating to release reducing gases. The volatile byproducts perform two primary functions: (i promoting the reduction of the GO and (ii providing the nitrogen to be inserted in situ as the graphene structure is created. Samples with diverse urea/GO mass ratios were treated at 800 °C in inert atmosphere to generate graphene with diverse microstructural characteristics and levels of nitrogen doping. Scanning electron microscopy (SEM and transmission electron microscopy (TEM were used to study the microstructural features of the products. The effects of doping on the samples structure and surface area were studied by X-ray diffraction (XRD, Raman Spectroscopy, and Brunauer Emmet Teller (BET. The GO and urea decomposition-reduction process as well as nitrogen-doped graphene stability were studied by thermogravimetric analysis (TGA coupled with mass spectroscopy (MS analysis of the evolved gases. Results show that the proposed method offers a high level of control over the amount of nitrogen inserted in the graphene and may be used alternatively to control its surface area. To demonstrate the practical relevance of these findings, as-produced samples were used as electrodes in supercapacitor and battery devices and compared with conventional, thermally exfoliated graphene.

Optical properties and defect levels in a surface layer found on CuInSe{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Abulfotuh, F.; Wangensteen, T.; Ahrenkiel, R.; Kazmerski, L.L. [National Renewable Energy Lab., Golden, CO (United States)

1996-05-01

In this paper the authors have used photoluminescence (PL) and wavelength scanning ellipsometry (WSE) to clarify the relationship among the electro-optical properties of copper indium diselenide (CIS) thin films, the type and origin of dominant defect states, and device performance. The PL study has revealed several shallow acceptor and donor levels dominating the semiconductor. PL emission from points at different depths from the surface of the CIS sample has been obtained by changing the angle of incidence of the excitation laser beam. The resulting data were used to determine the dominant defect states as a function of composition gradient at the surface of the chalcopyrite compound. The significance of this type of measurement is that it allowed the detection of a very thin layer with a larger bandgap (1.15-1.26 eV) than the CIS present on the surface of the CIS thin films. The presence of this layer has been correlated by several groups to improvement of the CIS cell performance. An important need that results from detecting this layer on the surface of the CIS semiconductor is the determination of its thickness and optical constants (n, k) as a function of wavelength. The thickness of this surface layer is about 500 {Angstrom}.

Surface erosion and hydrology of earth covers used in shallow land burial of low-level radioactive waste

International Nuclear Information System (INIS)

Bent, G.C.

1988-01-01

Shallow land burial is the current method of disposal of low-level radioactive waste in the United States. The most serious technical problems encountered in shallow land burial are water-related. Water is reported to come into contact with the waste by erosion of earth covers or through infiltration of precipitation through the earth covers. The objectives of this study were to: compare and evaluate the effects of crested wheatgrass and streambank wheatgrass on surface erosion of simulated earth covers at Idaho National Engineering Laboratory (INEL), characterize the surface hydrology, and estimate cumulative soil loss for average and extreme rainfall events and determine if the waste will become exposed during its burial life due to erosion. 30 refs., 26 figs., 21 tabs

Effect of age and gender on the surface electromyogram during various levels of isometric contraction.

Science.gov (United States)

Arjunan, Sridhar; Kumar, Dinesh; Kalra, Chandan; Burne, John; Bastos, Teodiano

2011-01-01

This study reports the effects of age and gender on the surface electromyogram while performing isometric contraction. Experiments were conducted with two age groups--Young (Age: 20-29) and Old (Age: 60-69) where they performed sustained isometric contractions at various force levels (50%, 75%, 100% of maximum voluntary contraction). Traditional features such as root mean square (RMS) and median frequency (MDF) were computed from the recorded sEMG. The result indicates that the MDF of sEMG was not significantly affected by age, but was impacted by gender in both age groups. Also there was a significant change in the RMS of sEMG with age and gender at all levels of contraction. The results also indicate a large inter-subject variation. This study will provide an understanding of the underlying physiological effects of muscle contraction and muscle fatigue in different cohorts.

Full-Dimensional Quantum Calculations of Vibrational Levels of NH4(+) and Isotopomers on An Accurate Ab Initio Potential Energy Surface.

Science.gov (United States)

Yu, Hua-Gen; Han, Huixian; Guo, Hua

2016-04-14

Vibrational energy levels of the ammonium cation (NH4(+)) and its deuterated isotopomers are calculated using a numerically exact kinetic energy operator on a recently developed nine-dimensional permutation invariant semiglobal potential energy surface fitted to a large number of high-level ab initio points. Like CH4, the vibrational levels of NH4(+) and ND4(+) exhibit a polyad structure, characterized by a collective quantum number P = 2(v1 + v3) + v2 + v4. The low-lying vibrational levels of all isotopomers are assigned and the agreement with available experimental data is better than 1 cm(-1).

Statistical analysis of lake levels and field study of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015: Chapter A of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

Science.gov (United States)

Jones, Perry M.; Trost, Jared J.; Diekoff, Aliesha L.; Rosenberry, Donald O.; White, Eric A.; Erickson, Melinda L.; Morel, Daniel L.; Heck, Jessica M.

2016-10-19

Water levels declined from 2003 to 2011 in many lakes in Ramsey and Washington Counties in the northeast Twin Cities Metropolitan Area, Minnesota; however, water levels in other northeast Twin Cities Metropolitan Area lakes increased during the same period. Groundwater and surface-water exchanges can be important in determining lake levels where these exchanges are an important component of the water budget of a lake. An understanding of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area has been limited by the lack of hydrologic data. The U.S. Geological Survey, in cooperation with the Metropolitan Council and Minnesota Department of Health, completed a field and statistical study assessing lake-water levels and regional and local groundwater and surface-water exchanges near northeast Twin Cities Metropolitan Area lakes. This report documents the analysis of collected hydrologic, water-quality, and geophysical data; and existing hydrologic and geologic data to (1) assess the effect of physical setting and climate on lake-level fluctuations of selected lakes, (2) estimate potential percentages of surface-water contributions to well water across the northeast Twin Cities Metropolitan Area, (3) estimate general ages for waters extracted from the wells, and (4) assess groundwater inflow to lakes and lake-water outflow to aquifers downgradient from White Bear Lake. Statistical analyses of lake levels during short-term (2002–10) and long-term (1925–2014) periods were completed to help understand lake-level changes across the northeast Twin Cities Metropolitan Area. Comparison of 2002–10 lake levels to several landscape and geologic characteristics explained variability in lake-level changes for 96 northeast Twin Cities Metropolitan Area lakes. Application of several statistical methods determined that (1) closed-basin lakes (without an active outlet) had larger lake-level declines than flow-through lakes with an outlet; (2

Maximum surface level and temperature histories for Hanford waste tanks

International Nuclear Information System (INIS)

Flanagan, B.D.; Ha, N.D.; Huisingh, J.S.

1994-01-01

Radioactive defense waste resulting from the chemical processing of spent nuclear fuel has been accumulating at the Hanford Site since 1944. This waste is stored in underground waste-storage tanks. The Hanford Site Tank Farm Facilities Interim Safety Basis (ISB) provides a ready reference to the safety envelope for applicable tank farm facilities and installations. During preparation of the ISB, tank structural integrity concerns were identified as a key element in defining the safety envelope. These concerns, along with several deficiencies in the technical bases associated with the structural integrity issues and the corresponding operational limits/controls specified for conduct of normal tank farm operations are documented in the ISB. Consequently, a plan was initiated to upgrade the safety envelope technical bases by conducting Accelerated Safety Analyses-Phase 1 (ASA-Phase 1) sensitivity studies and additional structural evaluations. The purpose of this report is to facilitate the ASA-Phase 1 studies and future analyses of the single-shell tanks (SSTs) and double-shell tanks (DSTs) by compiling a quantitative summary of some of the past operating conditions the tanks have experienced during their existence. This report documents the available summaries of recorded maximum surface levels and maximum waste temperatures and references other sources for more specific data

Model of the material removal function and an experimental study on a magnetorheological finishing process using a small ball-end permanent-magnet polishing head.

Science.gov (United States)

Chen, Mingjun; Liu, Henan; Cheng, Jian; Yu, Bo; Fang, Zhen

2017-07-01

In order to achieve the deterministic finishing of optical components with concave surfaces of a curvature radius less than 10 mm, a novel magnetorheological finishing (MRF) process using a small ball-end permanent-magnet polishing head with a diameter of 4 mm is introduced. The characteristics of material removal in the proposed MRF process are studied. The model of the material removal function for the proposed MRF process is established based on the three-dimensional hydrodynamics analysis and Preston's equation. The shear stress on the workpiece surface is calculated by means of resolving the presented mathematical model using a numerical solution method. The analysis result reveals that the material removal in the proposed MRF process shows a positive dependence on shear stress. Experimental research is conducted to investigate the effect of processing parameters on the material removal rate and improve the surface accuracy of a typical rotational symmetrical optical component. The experimental results show that the surface accuracy of the finished component of K9 glass material has been improved to 0.14 μm (PV) from the initial 0.8 μm (PV), and the finished surface roughness Ra is 0.0024 μm. It indicates that the proposed MRF process can be used to achieve the deterministic removal of surface material and perform the nanofinishing of small curvature radius concave surfaces.

A Continuous Liquid-Level Sensor for Fuel Tanks Based on Surface Plasmon Resonance

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Antonio M. Pozo

2016-05-01

Full Text Available A standard problem in large tanks at oil refineries and petrol stations is that water and fuel usually occupy the same tank. This is undesirable and causes problems such as corrosion in the tanks. Normally, the water level in tanks is unknown, with the problems that this entails. We propose herein a method based on surface plasmon resonance (SPR to detect in real time the interfaces in a tank which can simultaneously contain water, gasoline (or diesel and air. The plasmonic sensor is composed of a hemispherical glass prism, a magnesium fluoride layer, and a gold layer. We have optimized the structural parameters of the sensor from the theoretical modeling of the reflectance curve. The sensor detects water-fuel and fuel-air interfaces and measures the level of each liquid in real time. This sensor is recommended for inflammable liquids because inside the tank there are no electrical or electronic signals which could cause explosions. The sensor proposed has a sensitivity of between 1.2 and 3.5 RIU−1 and a resolution of between 5.7 × 10−4 and 16.5 × 10−4 RIU.

Genus- and species-level identification of dermatophyte fungi by surface-enhanced Raman spectroscopy

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Witkowska, Evelin; Jagielski, Tomasz; Kamińska, Agnieszka

2018-03-01

This paper demonstrates that surface-enhanced Raman spectroscopy (SERS) coupled with principal component analysis (PCA) can serve as a fast and reliable technique for detection and identification of dermatophyte fungi at both genus and species level. Dermatophyte infections are the most common mycotic diseases worldwide, affecting a quarter of the human population. Currently, there is no optimal method for detection and identification of fungal diseases, as each has certain limitations. Here, for the first time, we have achieved with a high accuracy, differentiation of dermatophytes representing three major genera, i.e. Trichophyton, Microsporum, and Epidermophyton. Two first principal components (PC), namely PC-1 and PC-2, gave together 97% of total variance. Additionally, species-level identification within the Trichophyton genus has been performed. PC-1 and PC-2, which are the most diagnostically significant, explain 98% of the variance in the data obtained from spectra of: Trichophyton rubrum, Trichophyton menatgrophytes, Trichophyton interdigitale and Trichophyton tonsurans. This study offers a new diagnostic approach for the identification of dermatophytes. Being fast, reliable and cost-effective, it has the potential to be incorporated in the clinical practice to improve diagnostics of medically important fungi.