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Sample records for triangular metal wedges

  1. Triangular metal wedges for subwavelength plasmon-polariton guiding at telecom wavelengths

    DEFF Research Database (Denmark)

    Boltasseva, Alexandra; Volkov, V.S.; Nielsen, Rasmus Bundgaard

    2008-01-01

    We report on subwavelength plasmon-polariton guiding by triangular metal wedges at telecom wavelengths. A high-quality fabrication procedure for making gold wedge waveguides, which is also mass- production compatible offering large-scale parallel fabrication of plasmonic components, is developed...

  2. Graphene Plasmons in Triangular Wedges and Grooves

    DEFF Research Database (Denmark)

    Gonçalves, P. A. D.; Dias, E. J. C.; Xiao, Sanshui

    2016-01-01

    and tunability of graphene plasmons guided along the apex of a graphene-covered dielectric wedge or groove. In particular, we present a quasi-analytic model to describe the plasmonic eigenmodes in such a system, including the complete determination of their spectrum and corresponding induced potential...... and electric-field distributions. We have found that the dispersion of wedge/groove graphene plasmons follows the same functional dependence as their flat-graphene plasmon counterparts, but now scaled by a (purely) geometric factor in which all the information about the system’s geometry is contained. We...

  3. Robust band gap and half-metallicity in graphene with triangular perforations

    DEFF Research Database (Denmark)

    Gregersen, Søren Schou; Power, Stephen; Jauho, Antti-Pekka

    2016-01-01

    . The inclusion of spin polarization within a mean-field Hubbard approach gives rise to a large overall magnetic moment at each antidot due to the sublattice imbalance imposed by the triangular geometry. Half-metallic behavior arises from the formation of spin-split dispersive states near the Fermi energy...... disorders. Here we study a rectangular array of triangular antidots with zigzag edge geometries and show that their band gap behavior qualitatively differs from the standard behavior which is exhibited, e.g., by rectangular arrays of armchair-edged triangles. In the spin unpolarized case, zigzag......, and furthermore, of exploiting the strong spin dependence of the system for spintronic applications....

  4. Robust band gap and half-metallicity in graphene with triangular perforations

    Science.gov (United States)

    Gregersen, Søren Schou; Power, Stephen R.; Jauho, Antti-Pekka

    2016-06-01

    Ideal graphene antidot lattices are predicted to show promising band gap behavior (i.e., EG≃500 meV) under carefully specified conditions. However, for the structures studied so far this behavior is critically dependent on superlattice geometry and is not robust against experimentally realistic disorders. Here we study a rectangular array of triangular antidots with zigzag edge geometries and show that their band gap behavior qualitatively differs from the standard behavior which is exhibited, e.g., by rectangular arrays of armchair-edged triangles. In the spin unpolarized case, zigzag-edged antidots give rise to large band gaps compared to armchair-edged antidots, irrespective of the rules which govern the existence of gaps in armchair-edged antidot lattices. In addition the zigzag-edged antidots appear more robust than armchair-edged antidots in the presence of geometrical disorder. The inclusion of spin polarization within a mean-field Hubbard approach gives rise to a large overall magnetic moment at each antidot due to the sublattice imbalance imposed by the triangular geometry. Half-metallic behavior arises from the formation of spin-split dispersive states near the Fermi energy, reducing the band gaps compared to the unpolarized case. This behavior is also found to be robust in the presence of disorder. Our results highlight the possibilities of using triangular perforations in graphene to open electronic band gaps in systems with experimentally realistic levels of disorder, and furthermore, of exploiting the strong spin dependence of the system for spintronic applications.

  5. Magnetic anisotropy of two-dimensional nanostructures: Transition-metal triangular stripes

    International Nuclear Information System (INIS)

    Dorantes-Davila, J.; Villasenor-Gonzalez, P.; Pastor, G.M.

    2005-01-01

    The magnetic anisotropy energy (MAE) of one-dimensional stripes having infinite length and triangular lateral structure are investigated in the framework of a self-consistent tight-binding method. One observes discontinuous changes in the easy magnetization direction along the crossover from one to two dimensions. The MAE oscillates as a function of stripe width and depends strongly on the considered transition metal (TM). The MAE of the two-leg ladder is strongly reduced as compared to that of the monoatomic chain and the convergence to the two-dimensional limit is rather slow

  6. Effectiveness of Rotation-free Triangular and Quadrilateral Shell Elements in Sheet-metal Forming Simulations

    International Nuclear Information System (INIS)

    Brunet, M.; Sabourin, F.

    2005-01-01

    This paper is concerned with the effectiveness of triangular 3-node shell element without rotational d.o.f. and the extension to a new 4-node quadrilateral shell element called S4 with only 3 translational degrees of freedom per node and one-point integration. The curvatures are computed resorting to the surrounding elements. Extension from rotation-free triangular element to a quadrilateral element requires internal curvatures in order to avoid singular bending stiffness. Two numerical examples with regular and irregular meshes are performed to show the convergence and accuracy. Deep-drawing of a box, spring-back analysis of a U-shape strip sheet and the crash simulation of a beam-box complete the demonstration of the bending capabilities of the proposed rotation-free triangular and quadrilateral elements

  7. Radiographic evaluation of 19 patients with Paprosky 3A and 3B submitted to acetabular review with trabecular metal wedge

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Benvindo Rosal da Fonseca Neto

    Full Text Available ABSTRACT Objective: This study is aimed at evaluating the fixation of trabecular metal wedges in patients who underwent revision of total hip arthroplasty with large acetabular bone defects. Methods: The radiographs of 19 patients (21 hips, who underwent revision of total hip arthroplasty using trabecular metal wedges from September 2010 to December 2014 were evaluated. This study included only cases of Paprosky 3A and 3B. Preoperative and postoperative images were analyzed. Non-fixation of the implant was defined by the presence of angular variation of the component higher 10 degrees or displacement greater than 6 mm. Patients with follow-up times of less than 24 months or who did not attend the last two appointments were excluded from the study. Results: The mean follow-up time was 39.4 months (25-61. Fixation was achieved in all cases despite its complexity. There was only one case of dislocation that was treated with open reduction. One case developed infection, and was surgically approached on two occasions, with extensive debridement and intravenous antibiotics following protocol, with good evolution. Conclusion: The implanted trabecular metal wedges showed excellent results in the short- and medium-term and may represent another option in the reconstruction of large acetabular defects, sometimes replacing bone reconstruction that uses bone tissue banks or autologous graft.

  8. Triangular Numbers

    Indian Academy of Sciences (India)

    Admin

    Triangular number, figurate num- ber, rangoli, Brahmagupta–Pell equation, Jacobi triple product identity. Figure 1. The first four triangular numbers. Left: Anuradha S Garge completed her PhD from. Pune University in 2008 under the supervision of Prof. S A Katre. Her research interests include K-theory and number theory.

  9. Robust band gap and half-metallicity in graphene with triangular perforations

    DEFF Research Database (Denmark)

    Gregersen, Søren Schou; Power, Stephen; Jauho, Antti-Pekka

    2016-01-01

    Ideal graphene antidot lattices are predicted to show promising band gap behavior (i.e., EG ≅ 500 meV) under carefully specified conditions. However, for the structures studied so far this behavior is critically dependent on superlattice geometry and is not robust against experimentally realistic...... disorders. Here we study a rectangular array of triangular antidots with zigzag edge geometries and show that their band gap behavior qualitatively differs from the standard behavior which is exhibited, e.g., by rectangular arrays of armchair-edged triangles. In the spin unpolarized case, zigzag......-edged antidots give rise to large band gaps compared to armchair-edged antidots, irrespective of the rules which govern the existence of gaps in armchair-edged antidot lattices. In addition the zigzag-edged antidots appear more robust than armchair-edged antidots in the presence of geometrical disorder...

  10. An ancient stone facing strengthening with metal wedges at Iasos (Caria

    Directory of Open Access Journals (Sweden)

    Paolo Vitti

    2017-12-01

    Full Text Available This paper discusses a masonry strengthening on the wall of the Great bath building at Iasos in Caria. The analysis is based on the observation of a peculiar use of iron elements, inserted in the joints of a wall of the caldarium. The survey and the study of the wall has demonstrated that the facing of the wall separated from its core, probably due to an earthquake. The damage is likely to have occurred because of the big and heavy stones of the facing which were not bonded to the core of the wall. The use of iron wedges might have been an ideal solution for strengthening the wall without dismantling it.

  11. Wedges I

    International Nuclear Information System (INIS)

    DeWitt-Morette, C.; Low, S.G.; Schulman, L.S.; Shiekh, A.Y.

    1986-01-01

    The wedge problem, that is, the propagation of radiation or particles in the presence of a wedge, is examined in different contexts. Generally, the paper follows the historical order from Sommerfeld's early work to recent stochastic results - hindsights and new results being woven in as appropriate. In each context, identifying the relevant mathematical problem has been the key to the solution. Thus each section can be given both a physics and a mathematics title: Section 2: diffraction by reflecting wedge; boundary value problem of differential equations; solutions defined on multiply connected spaces. Section 3: geometrical theory of diffraction; identification of function spaces. Section 4: path integral solutions; path integration on multiply connected spaces; asymptotics on the boundaries of function spaces. Section 5: probing the shape of the wedge and the roughness of its surface; stochastic calculus. Several propagators and Green functions are given explicitly, some old ones and some new ones. They include the knife-edge propagator for Dirichlet and Neumann boundary conditions, the absorbing knife edge propagator, the wedge propagators, the propagator for a free particle on a /sigma phi/-sheeted Riemann surface, the Dirichlet and the Neumann wedge Green function

  12. Reliability Tests of Aluminium Wedge Wire Bonding on Auto-catalytic Silver Immersion Gold (ASIG) PCB Metallization

    CERN Document Server

    Drozd, A; Kaufmann, S; Manolescu, F; McGill, I

    2011-01-01

    The Auto-catalytic Silver Immersion Gold (ASIG) PCB metallization is a new process that has clear advantages for PCB assembly especially with regard to lead-free soldering. As it may become a popular process in the future for electronics used in physics experiments, the quality of this metallization for aluminium wire bonding has been studied. Aluminium wedge wire bonding continues to be the interconnection method of choice for many physics detector sensors, for high density signal routing and for unpackaged die. Although advertised as having good quality for aluminium wire bonding, this study was performed to verify this claim as well as to test the longer term reliability of the wire bonds taking into consideration the environmental conditions and life-expectancy of devices, in particular for high energy physics detector applications. The tests were performed on PCBs made with the ASIG and ENIG (Electro-less Nickel Immersion Gold) processes at the same time in order to make a comparison with the current ind...

  13. Simultaneous triangularization

    CERN Document Server

    Radjavi, Heydar

    2000-01-01

    A collection of matrices is said to be triangularizable if there is an invertible matrix S such that S1 AS is upper triangular for every A in the collection. This generalization of commutativity is the subject of many classical theorems due to Engel, Kolchin, Kaplansky, McCoy and others. The concept has been extended to collections of bounded linear operators on Banach spaces: such a collection is defined to be triangularizable if there is a maximal chain of subspaces of the Banach space, each of which is invariant under every member of the collection. Most of the classical results have been generalized to compact operators, and there are also recent theorems in the finite-dimensional case. This book is the first comprehensive treatment of triangularizability in both the finite and infinite-dimensional cases. It contains numerous very recent results and new proofs of many of the classical theorems. It provides a thorough background for research in both the linear-algebraic and operator-theoretic aspects of tr...

  14. Rethinking wedges

    Science.gov (United States)

    Davis, Steven J.; Cao, Long; Caldeira, Ken; Hoffert, Martin I.

    2013-03-01

    Abstract Stabilizing CO2 emissions at current levels for fifty years is not consistent with either an atmospheric CO2 concentration below 500 ppm or global temperature increases below 2 °C. Accepting these targets, solving the climate problem requires that emissions peak and decline in the next few decades, and ultimately fall to near zero. Phasing out emissions over 50 years could be achieved by deploying on the order of 19 'wedges', each of which ramps up linearly over a period of 50 years to ultimately avoid 1 GtC y-1 of CO2 emissions. But this level of mitigation will require affordable carbon-free energy systems to be deployed at the scale of tens of terawatts. Any hope for such fundamental and disruptive transformation of the global energy system depends upon coordinated efforts to innovate, plan, and deploy new transportation and energy systems that can provide affordable energy at this scale without emitting CO2 to the atmosphere. 1. Introduction In 2004, Pacala and Socolow published a study in Science arguing that '[h]umanity can solve the carbon and climate problem in the first half of this century simply by scaling up what we already know how to do' [1]. Specifically, they presented 15 options for 'stabilization wedges' that would grow linearly from zero to 1 Gt of carbon emissions avoided per year (GtC y-1 1 Gt = 1012 kg) over 50 years. The solution to the carbon and climate problem, they asserted, was 'to deploy the technologies and/or lifestyle changes necessary to fill all seven wedges of the stabilization triangle'. They claimed this would offset the growth of emissions and put us on a trajectory to stabilize atmospheric CO2 concentration at 500 ppm if emissions decreased sharply in the second half of the 21st century. The wedge concept has proven popular as an analytical tool for considering the potential of different technologies to reduce CO2 emissions. In the years since the paper was published, it has been cited more than 400 times, and

  15. Radial wedge flange clamp

    Science.gov (United States)

    Smith, Karl H.

    2002-01-01

    A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

  16. Triangularization of a Matrix

    Indian Academy of Sciences (India)

    Much of linear algebra is devoted to reducing a matrix (via similarity or unitary similarity) to another that has lots of zeros. The simplest such theorem is the Schur triangularization theorem. This says that every matrix is unitarily similar to an upper triangular matrix. Our aim here is to show that though it is very easy to prove it ...

  17. Heredity for triangular operators

    Directory of Open Access Journals (Sweden)

    Henry Crawford Rhaly Jr.

    2013-12-01

    Full Text Available A proof is given that if the lower triangular infinite matrix $T$ acts boundedly on $\\ell^2$ and U is the unilateral shift, the sequence $(U^*^nTU^n$ inherits from $T$ the following properties: posinormality, dominance, $M$-hyponormality, hyponormality, normality, compactness, and noncompactness.  Also, it is demonstrated that the upper triangular matrix $T^*$ is dominant if and only if $T$ is a diagonal matrix.

  18. Role of an anatomically contoured plate and metal block for balanced stability between the implant and lateral hinge in open-wedge high-tibial osteotomy.

    Science.gov (United States)

    Jang, Young Woong; Lim, DoHyung; Seo, Hansol; Lee, Myung Chul; Lee, O-Sung; Lee, Yong Seuk

    2018-07-01

    Open-wedge high tibial osteotomy (OWHTO) is a well-established surgical option for medial compartment osteoarthritis of the varus knee. The initial strength of the fixation plate is critical for successful correction maintenance and healing of the osteotomy site. This study was conducted to verify if a newly designed anatomical plate (LCfit) improves the stability of both the medial implant and lateral hinge area, as well as to evaluate how the metal block contributes to both medial and lateral stability. A finite element (FE) tibial model was combined with TomoFix plate, a LCfit plate with and without a metal block. Data analysis was conducted to evaluate the balanced stability, which refers to the enforced lateral stability resulting from redistribution of overall stress. We assessed the balanced stability of the medial implant and lateral hinge area in three cases using the same Sawbones and loads using the tibia FE model. The LCfit plate reduced stress by 23.1% at the lateral hinge compared to the TomoFix plate (TomoFix vs. LCfit: 34.2 ± 23.3 MPa vs. 26.3 ± 17.5 MPa). The LCfit plate with a metal block reduced stress by 40.1% at the medial plate (210.1 ± 64.2 MPa vs. 125.8 ± 65.7 MPa) and by 31.2% (26.3 ± 17.5 MPa vs. 18.1 ± 12.1 MPa) at the lateral hinge area compared to the reduction using the LCfit plate without a metal block. The newly designed fixation system for OWHTO balanced the overall stress distribution and reduced stress at the lateral hinge area compared to that using a conventional fixation system. The addition of the metal block showed additional benefits for balanced stability between the medial implant and lateral hinge area. However, this conclusion could only be drawn using the FE model in this study. Therefore, further clinical studies are necessary to reveal the clinical effect of reduced lateral stress on the occurrence of the lateral hinge fracture and the biologic effect of the metal block on the

  19. Triangular spiral tilings

    International Nuclear Information System (INIS)

    Sushida, Takamichi; Hizume, Akio; Yamagishi, Yoshikazu

    2012-01-01

    The topology of spiral tilings is intimately related to phyllotaxis theory and continued fractions. A quadrilateral spiral tiling is determined by a suitable chosen triple (ζ, m, n), where ζ element of D/R, and m and n are relatively prime integers. We give a simple characterization when (ζ, m, n) produce a triangular spiral tiling. When m and n are fixed, the admissible generators ζ form a curve in the unit disk. The family of triangular spiral tilings with opposed parastichy pairs (m, n) is parameterized by the divergence angle arg (ζ), while triangular spiral tilings with non-opposed parastichy pairs are parameterized by the plastochrone ratio 1/|ζ|. The generators for triangular spiral tilings with opposed parastichy pairs are not dense in the complex parameter space, while those with non-opposed parastichy pairs are dense. The proofs will be given in a general setting of spiral multiple tilings. We present paper-folding (origami) sheets that build spiral towers whose top-down views are triangular tilings. (paper)

  20. Modelling the wedge shape for the virtual wedge

    International Nuclear Information System (INIS)

    Chang Liyun; Ho Shengyow; Chen, Helen H W

    2003-01-01

    We present a method to model the virtual wedge shape in a 3D treatment planning system as a physical wedge. The virtual wedge shape was determined using the measured dose profile of the virtual wedge at a chosen reference depth. The differences between the calculated and the measured dose profiles for the virtual wedge were within 0.5% at the reference depth, and within 2.5% at other depths. This method provides a fast and accurate way to implement the virtual wedge into our planning system for any wedge angles. This method is also applicable to model the physical wedge shapes with comparable good results

  1. Physical characteristics comparison of virtual wedge device with physical wedge

    International Nuclear Information System (INIS)

    Cho, Jung Keun; Choi, Kye Sook; Lim, Cheong Hwan; Kim, Jeong Koo; Jung, Hong Ryang; Lee, Jung Ok; Lee, Man Goo

    2001-01-01

    We compared the characteristics of Siemens virtual wedge device with physical wedges for clinical application. We investigated the characteristics of virtual and physical wedges for various wedge angles (15, 30, 45, and 60) using 6- and 15- MV photon beams. Wedge factors were measured in water using an ion chamber for various field sizes and depths. In case of virtual wedge device, as upper jaw moves during irradiation, wedge angles were estimated by accumulated doses. These measurements were performed at off-axis points perpendicular to the beam central axis in water for a 15 cm x 20 cm radiation field size at the depth of 10 cm. Surface does without and with virtual or physical wedges were measured using a parallel plate ion chamber at surface. Field size was 15 cm * 20 cm and a polystyrene phantom was used. For various field sizes, virtual and physical wedge factors were changed by maximum 2.1% and 3.9%, respectively. For various depths, virtual and physical wedge factors were changed by maximum 1.9% and 2.9%, respectively. No major difference was found between the virtual and physical wedge angles and the difference was within 0.5. Surface dose with physical wedge was reduced by maximum 20% (x-ray beam : 6 MV, wedge angle : 45, SSD : 80 cm) relative to one with virtual wedge or without wedge. Comparison of the characteristics of Siemens virtual wedge device with physical wedges was performed. Depth dependence of virtual wedge factor was smaller than that of physical wedge factor. Virtual and physical wedge factors were nearly independent of field sizes. The accuracy of virtual and physical wedge angles was excellent. Surface dose was found to be reduced using a physical wedge

  2. Physical characteristics comparison of virtual wedge device with physical wedge

    International Nuclear Information System (INIS)

    Choi, Dong Rak; Shin, Kyung Hwan; Lee, Kyu Chan; Kim, Dae Yong; Ahn, Yong Chan; Lim, Do Hoon; Kim, Moon Kyung; Huh, Seung Jae

    1999-01-01

    We have compared the characteristics of Siemens virtual wedge device with physical wedges for clinical application. We investigated the characteristics of virtual and physical wedges for various wedge angles (15, 30, 45, and 60 ) using 6- and 15MV photon beams. Wedge factors were measured in water using an ion chamber for various field sizes and depths. In case of virtual wedge device, as upper jaw moves during irradiation, wedge angles were estimated by accumulated doses. These measurements were performed at off-axis points perpendicular to the beam central axis in water for a 15 cm x 20 cm radiation field size at the depth of 10 cm. Surface doses without and with virtual or physical wedges were measured using a parallel plate ion chamber at surface. Field size was 15 cm x 20 cm and a polystyrene phantom was used. For various field sizes, virtual and physical wedge factors were changed by maximum 2.1% and 3.9%, respectively. For various depths, virtual and physical wedge factors were changed by maximum 1.9% and 2.9%, respectively. No major difference was found between the virtual and physical wedge angles and the difference was within 0.5 .deg. . Surface dose with physical wedge was reduced by maximum 20% (x-ray beam: 6 MV, wedge angle: 45 .deg. , SSD: 80cm) relative to one with virtual wedge or without wedge. Comparison of the characteristics of Siemens virtual wedge device with physical wedges was performed. Depth dependence of virtual wedge factor was smaller than that of physical wedge factor. Virtual and physical wedge factors were nearly independent of field sizes. The accuracy of virtual and physical wedge angles was excellent. Surface dose was found to be reduced using physical wedge

  3. Wedged multilayer Laue lens

    International Nuclear Information System (INIS)

    Conley, Ray; Liu Chian; Qian Jun; Kewish, Cameron M.; Macrander, Albert T.; Yan Hanfei; Maser, Joerg; Kang, Hyon Chol; Stephenson, G. Brian

    2008-01-01

    A multilayer Laue lens (MLL) is an x-ray focusing optic fabricated from a multilayer structure consisting of thousands of layers of two different materials produced by thin-film deposition. The sequence of layer thicknesses is controlled to satisfy the Fresnel zone plate law and the multilayer is sectioned to form the optic. An improved MLL geometry can be created by growing each layer with an in-plane thickness gradient to form a wedge, so that every interface makes the correct angle with the incident beam for symmetric Bragg diffraction. The ultimate hard x-ray focusing performance of a wedged MLL has been predicted to be significantly better than that of a nonwedged MLL, giving subnanometer resolution with high efficiency. Here, we describe a method to deposit the multilayer structure needed for an ideal wedged MLL and report our initial deposition results to produce these structures

  4. Wedges of Anxiety

    DEFF Research Database (Denmark)

    Hellström, Maria; Brandt, Eva

    2005-01-01

    The Heraclitian notion of a reality in constant flux seems to have settled even in the public consciousness. We are, to an ever-increasing extent, on the move; in motion between different places of abode, between domiciles and places of residence, between temporary addresses and provisory settlem...... cones of light, as the cut their way into the unknown, like wedges of anxiety...

  5. Triangular arbitrage in the foreign exchange market

    Science.gov (United States)

    Aiba, Yukihiro; Hatano, Naomichi

    2004-12-01

    We first review our previous work, showing what is the triangular arbitrage transaction and how to quantify the triangular arbitrage opportunity. Next we explain that the correlation of the foreign exchange rates can appear without actual triangular arbitrage transaction.

  6. Clinical Application of Wedge Factor

    International Nuclear Information System (INIS)

    Choi, Dong Rak; Ahn, Yong Chan; Huh, Sueng Jae

    1995-01-01

    Purpose : In general. The wedge factors which are used clinical practices are ignored of dependency on field sizes and depths. In this present, we investigated systematically the depth and field size dependency to determine the absorbed dose more accurately. Methods : The wedge factors for each wedge filter were measured at various depth (depth of Dmax, 5cm, 10cm, and 15cm) and field sizes (5 X 5cm, 10 X 10cm, 15 X 15cm, 20 X 20 cm) by using 4-,6-, and 10-MV X rays. By convention, wedge factors are determined by taking the ratio of the central axis ionization readings when the wedge filter is in place to those of the open field in same field size and measurement depth. In this present work, we determined the wedge factors for 4-, 6-, and 10-MV X rays from Clinac 600C and 2100C linear accelerators (manufactured by Varian Associates, Inc., Palo Alto, CA). To confirm that the wedge was centered., measurements were done with the two possible wedge position and various collimator orientations. Results : The standard deviations of measured values are within 0.3% and the depth dependence of wedge factor is greater for the lower energies. Especially, the variation of wedge factor is no less than 5% for 4- and 6- MV X rays with more than 45 .deg. wedge filter. But there seems to be a small dependence on field size. Conclusion : The results of this study show a dependence on the point of measurement. There also seems to be a small dependence on field size. And so, we should consider the depth and field size dependence in determining the wedge factors. If one wedge factor were to be used for each wedge filter, it seems that the measurement for a 10cm X 10cm field size at a depth of 10cm would be a reasonable choice

  7. Impartial Triangular Chocolate Bar Games

    OpenAIRE

    Miyadera, Ryohei; Nakamura, Shunsuke; Fukui, Masanori

    2017-01-01

    Chocolate bar games are variants of the game of Nim in which the goal is to leave your opponent with the single bitter part of the chocolate bar. The rectangular chocolate bar game is a thinly disguised form of classical multi-heap Nim. In this work, we investigate the mathematical structure of triangular chocolate bar games in which the triangular chocolate bar can be cut in three directions. In the triangular chocolate bar game, a position is a $\\mathcal{P}$-position if and only if $x \\oplu...

  8. Heavy Metal Contents of Municipal and Rural Dumpsite Soils and Rate of Accumulation by Carica papaya and Talinum triangulare in Uyo, Nigeria

    Directory of Open Access Journals (Sweden)

    G. A. Ebong

    2008-01-01

    Full Text Available Dumpsites in Uyo and most cities in Nigeria are used nutrients rich soils for cultivating fruits and vegetables without regards to the risk of toxic metal pollution by the wastes. This development necessitated the research on the assessment of the impact of municipal and rural dumpsites on the metal levels of the underlying soils, the relationship between the dumpsite- soil metal content and the rate of bio-accumulation by plants, the effect of plant specie and plant part on the rate of metal uptake. Atomic absorption spectrophotometer was employed for the analysis of the samples and results obtained from municipal dumpsite soil indicated the following mean concentrations: Fe, 1711.20 μg/g; Pb, 43.28 ug/g; Zn, 88.34 ug/g; Ni, 12.18 ug/g; Cd, 14.10 ug/g and Cu, 56.33 ug/g. These concentrations were relatively higher than the following concentrations: Fe, 1016.98 ug/g; Pb, 18.57 ug/g; Zn, 57.90 ug/g; Ni, 7.98 ug/g; Cd, 9.25 ug/g and Cu, 33.70 ug/g recorded for the rural dumpsite soil. Consequently, plants grown on municipal dumpsites soil accumulated higher concentrations of the metals than those on rural dumpsites. Results obtained from this study also revealed that plants grown on dumpsite soils bio-accumulated higher metal concentrations than their counterparts obtained from normal agricultural soils. The ability of plants to bioaccumulate these metals were also observed as being different from one plant to the other and from one plant parts to the other. And apart from Fe and Zn which recorded higher concentrations in the leaves of the plants studied, other metals recorded higher concentrations in the roots. The general results obtained revealed that the levels of Cd in dumpsite-soil were above the standard while the levels of Cd and Pb in plants were also above the recommended levels in plants. The implications of these high concentrations of these metals in soil and plants have been discussed. Some useful recommendations on the proper

  9. Progress in triangular magnetohydrodynamics

    International Nuclear Information System (INIS)

    Schnack, D.D.; Mikic, Z.

    1993-01-01

    Many of the advances in our understanding of fusion plasmas over the past ten years has resulted from the application of techniques of large scale numerical simulation to three dimensional toroidal geometry. Since the dominant toroidal motions in a tokamak are generally long wavelength, finite Fourier series provides an efficient spatial representation for that coordinate. However, the next generation of numerical tokamak simulations will require that the poloidal cross section of actual experimental devices be more accurately represented. The authors address these difficulties by the application of an unstructured adaptive mesh to the representation of the poloidal plane, coupled with a finite Fourier representation of the toroidal coordinate. These meshes are not tied to a particular coordinate system, so that mesh points can be arbitrarily distributed to simulate the details of experimental apparatus. Since mesh points do not have a sequential orientation with their spatial neighbors, they can be easily added and deleted based on physical criteria. Evolving fine scale spatial structures are thus efficiently and accurately represented. The authors have derived an algorithm for the solution of the resistive MHD equations on these meshes. This algorithm is based on the triangulation of arbitrarily distributed points in the plane; hence the term triangular MHD. The algorithm preserves the solenoidal properties of B and J identically, and is a generalization of staggered mesh techniques used in structured, rectangular grids. A new 3-D MHD code, TRIM, based on this algorithm has been developed. Preliminary results from TRIM are presented

  10. Invariants of triangular Lie algebras

    International Nuclear Information System (INIS)

    Boyko, Vyacheslav; Patera, Jiri; Popovych, Roman

    2007-01-01

    Triangular Lie algebras are the Lie algebras which can be faithfully represented by triangular matrices of any finite size over the real/complex number field. In the paper invariants ('generalized Casimir operators') are found for three classes of Lie algebras, namely those which are either strictly or non-strictly triangular, and for so-called special upper triangular Lie algebras. Algebraic algorithm of Boyko et al (2006 J. Phys. A: Math. Gen.39 5749 (Preprint math-ph/0602046)), developed further in Boyko et al (2007 J. Phys. A: Math. Theor.40 113 (Preprint math-ph/0606045)), is used to determine the invariants. A conjecture of Tremblay and Winternitz (2001 J. Phys. A: Math. Gen.34 9085), concerning the number of independent invariants and their form, is corroborated

  11. Multiple Fano-Like MIM Plasmonic Structure Based on Triangular Resonator for Refractive Index Sensing

    OpenAIRE

    Jankovic, Nikolina; Cselyuszka, Norbert

    2018-01-01

    In this paper, we present a Fano metal-insulator-metal (MIM) structure based on an isosceles triangular cavity resonator for refractive index sensing applications. Due to the specific feeding scheme and asymmetry introduced in the triangular cavity, the resonator exhibits four sharp Fano-like resonances. The behavior of the structure is analyzed in detail and its sensing capabilities demonstrated through the responses for various refractive indices. The results show that the sensor has very g...

  12. Redesigning Triangular Dense Matrix Computations on GPUs

    KAUST Repository

    Charara, Ali; Ltaief, Hatem; Keyes, David E.

    2016-01-01

    A new implementation of the triangular matrix-matrix multiplication (TRMM) and the triangular solve (TRSM) kernels are described on GPU hardware accelerators. Although part of the Level 3 BLAS family, these highly computationally intensive kernels

  13. Subjectivity, objectivity, and triangular space.

    Science.gov (United States)

    Britton, Ronald

    2004-01-01

    The author reviews his ideas on subjectivity, objectivity, and the third position in the psychoanalytic encounter, particularly in clinical work with borderline and narcissistic patients. Using the theories of Melanie Klein and Wilfred Bion as a basis, the author describes his concept of triangular space. A case presentation of a particular type of narcissistic patient illustrates the principles discussed.

  14. Lie bialgebras with triangular decomposition

    International Nuclear Information System (INIS)

    Andruskiewitsch, N.; Levstein, F.

    1992-06-01

    Lie bialgebras originated in a triangular decomposition of the underlying Lie algebra are discussed. The explicit formulas for the quantization of the Heisenberg Lie algebra and some motion Lie algebras are given, as well as the algebra of rational functions on the quantum Heisenberg group and the formula for the universal R-matrix. (author). 17 refs

  15. Strange distributionally chaotic triangular maps

    International Nuclear Information System (INIS)

    Paganoni, L.; Smital, J.

    2005-01-01

    The notion of distributional chaos was introduced by Schweizer, Smital [Measures of chaos and a spectral decompostion of dynamical systems on the interval. Trans. Amer. Math. Soc. 344;1994:737-854] for continuous maps of the interval. For continuous maps of a compact metric space three mutually nonequivalent versions of distributional chaos, DC1-DC3, can be considered. In this paper we study distributional chaos in the class T m of triangular maps of the square which are monotone on the fibres; such maps must have zero topological entropy. The main results: (i) There is an F-bar T m such that F-bar DC2 and F vertical bar Rec(F)-bar DC3. (ii) If no ω-limit set of an F-bar T m contains two minimal subsets then F-bar DC1. This completes recent results obtained by Forti et al. [Dynamics of homeomorphisms on minimal sets generated by triangular mappings. Bull Austral Math Soc 59;1999:1-20], Smital, Stefankova [Distributional chaos for triangular maps, Chaos, Solitons and Fractals 21;2004:1125-8], and Balibrea et al. [The three versions of distributional chaos. Chaos, Solitons and Fractals 23;2005:1581-3]. The paper contributes to the solution of a long-standing open problem by Sharkovsky concerning classification of triangular maps

  16. SOFTWARE FOR COMPUTER-AIDED DESIGN OF CROSS-WEDGE ROLLING

    OpenAIRE

    A. A. Abramov; S. V. Medvedev

    2013-01-01

    The issues of computer technology creation of 3D-design and engineering analysis of metal forming processes using cross wedge rolling methods (CWR) are considered. The developed software for computer-aided design and simulation of cross-wedge rolling is described.

  17. Chevron closing base wedge bunionectomy.

    Science.gov (United States)

    Bruyn, J M

    1993-01-01

    The Chevron-base wedge Association for Osteosynthesis fixated bunionectomy provides a stable, aggressive correction of the severe hallux abducto valgus deformity. It is intended for the bunion requiring a double osteotomy in order to adequately reduce both intermetatarsal and proximal articular facet angle with minimal shortening and elevation. This article presents the rationale for the procedure, technique, and a 4-year follow-up of six patients with eight Chevron-base wedge bunionectomies.

  18. Phase Space Exchange in Thick Wedge Absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2017-01-01

    The problem of phase space exchange in wedge absorbers with ionization cooling is discussed. The wedge absorber exchanges transverse and longitudinal phase space by introducing a position-dependent energy loss. In this paper we note that the wedges used with ionization cooling are relatively thick, so that single wedges cause relatively large changes in beam phase space. Calculation methods adapted to such “thick wedge” cases are presented, and beam phase-space transformations through such wedges are discussed.

  19. Triangular fibrocartilage complex injury treated with prolotherapy

    Directory of Open Access Journals (Sweden)

    Serdar Kesikburun

    2016-06-01

    Full Text Available Triangular fibrocartilage complex has a crucial role in stability and functionality of the wrist. Traumatic or degenerative injury of the triangular fibrocartilage complex is a common cause of ulnar side wrist pain. Arthroscopic treatment has been offered in chronic triangular fibrocartilage complex injury. A 19-year old male patient presented with pain at ulnar side of the wrist. He was diagnosed as having triangular fibrocartilage complex injury after assessment with MR imaging. The patients who did not benefit from drugs underwent prolotherapy three times. After treatment, he had pain relief and reported that he could use his wrist better. In this case, triangular fibrocartilage complex injury improved with prolotherapy and arthroscopic treatment was not required. Further clinical trials are needed to show better the role of prolotherapy in the treatment of triangular fibrocartilage complex injury. [Cukurova Med J 2016; 41(2.000: 403-405

  20. Clinical implementation of enhanced dynamic wedge

    International Nuclear Information System (INIS)

    Klein, Eric E.; Zhu Xiaorong; Low, Daniel A.; Drzymala, Robert E.; Harms, William B.; Purdy, James A.

    1996-01-01

    Purpose/Objective: Our clinic has been using dynamic wedge since 1993. We appreciate the customized wedge shaped distributions (independent of field size) and the positive aspects of replacing filters with dynamic jaw motion. Varian recently introduced enhanced dynamic wedge (EDW) software. The EDW can be delivered over; a 30 cm field, asymmetric fields (in both wedged and non-wedged directions), and additional wedge angles (10, 15, 20, 25, 30, 45, 60). The EDW software creates customized segmented treatment tables (STTs) for the desired wedge angle and field size. The STT is created from a 'golden' fluence profile of 60 deg. over 30 cm. The wedge STT is derived using ratio-of-tangents and the truncated field segment extracted from the 'golden' table. A review of our dosimetric studies will be presented as well as a discussion of clinical implementation issues including treatment planning and quality assurance. Methods and Materials: We tested a set of angle and field size combinations chosen to encompass clinical needs. The wedge factor (WF) was measured using an ionization chamber along central axis for symmetric fields ranging from 4 to 20 cm, and asymmetric fields to 30 cm. The non-wedged field dimension was found to be inconsequential. An algorithm was developed to predict the wedge factor for any angle and field dimension. Isodoses were measured with film and used for profile evaluation and treatment planning development. The 'golden' fluence table was used to create a universal 60 deg. 'physical' wedge for planning. The universal wedge is combined with an open field (to derive intermediate wedge angles) and blocked according to the treatment field segment. A quality assurance program was developed that relies on multi-point diode measurements. Results: We found the WF is a function of wedge angle and field settings of the final sweep position. There is a nearly linear dependence of WF vs. field size thus allowing a minimal WF table. This eliminates a

  1. Portal dosimetry in wedged beams

    NARCIS (Netherlands)

    Spreeuw, Hanno; Rozendaal, Roel; Camargo, Priscilla; Mans, Anton; Wendling, Markus; Olaciregui-Ruiz, Igor; Sonke, Jan-Jakob; van Herk, Marcel; Mijnheer, Ben

    2015-01-01

    Portal dosimetry using electronic portal imaging devices (EPIDs) is often applied to verify high-energy photon beam treatments. Due to the change in photon energy spectrum, the resulting dose values are, however, not very accurate in the case of wedged beams if the pixel-to-dose conversion for the

  2. Calibration of the Wedge Prism

    Science.gov (United States)

    Charles B. Briscoe

    1957-01-01

    Since the introduction of plotless cruising in this country by Grosenbaugh and the later suggestion of using a wedge prism as an angle gauge by Bruce this method of determining basal area has been widely adopted in the South. One of the factors contributing to the occasionally unsatisfactory results obtained is failure to calibrate the prism used. As noted by Bruce the...

  3. Triangular Norms, Triangular Conorms, and Some Related Concepts

    Directory of Open Access Journals (Sweden)

    Angel Garrido

    2011-01-01

    Full Text Available Abstract. Mathematically considered, a Triangular Norm is a kind of binary operation frequently used in the context of Probabilistic Metric Spaces, but also in other very interesting fields, as may be Fuzzy Logic, or in general, in Multi-Valued Logic (MVL. The T-conorm, or S-norm, is a dual concept. Both ideas allow us to generalize the intersection and the union in a Lattice, or disjunction and conjunction in Logic. Also may be very interesting to introduce a special class of real monotone operations. We refer to the so-called Copulas, very useful in many fields. So, we offer now a comprehensive analysis of all these aggregation operators.

  4. Rainfall induced groundwater mound in wedge-shaped promontories: The Strack-Chernyshov model revisited

    Science.gov (United States)

    Kacimov, A. R.; Kayumov, I. R.; Al-Maktoumi, A.

    2016-11-01

    An analytical solution to the Poisson equation governing Strack's discharge potential (squared thickness of a saturated zone in an unconfined aquifer) is obtained in a wedge-shaped domain with given head boundary conditions on the wedge sides (specified water level in an open water body around a porous promontory). The discharge vector components, maximum elevation of the water table in promontory vertical cross-sections, quantity of groundwater seeping through segments of the wedge sides, the volume of fresh groundwater in the mound are found. For acute angles, the solution to the problem is non-unique and specification of the behaviour at infinity is needed. A ;basic; solution is distinguished, which minimizes the water table height above a horizontal bedrock. MODFLOW simulations are carried out in a finite triangular island and compare solutions with a constant-head, no-flow and ;basic; boundary condition on one side of the triangle. Far from the tip of an infinite-size promontory one has to be cautious with truncation of the simulated flow domains and imposing corresponding boundary conditions. For a right and obtuse wedge angles, there are no positive solutions for the case of constant accretion on the water table. In a particular case of a confined rigid wedge-shaped aquifer and incompressible fluid, from an explicit solution to the Laplace equation for the hydraulic head with arbitrary time-space varying boundary conditions along the promontory rays, essentially 2-D transient Darcian flows within the wedge are computed. They illustrate that surface water waves on the promontory boundaries can generate strong Darcian waves inside the porous wedge. Evaporation from the water table and sea-water intruded interface (rather than a horizontal bed) are straightforward generalizations for the Poissonian Strack potential.

  5. Problems on triangular norms and related operators

    Czech Academy of Sciences Publication Activity Database

    Klement, E.P.; Mesiar, Radko; Pap, E.

    2004-01-01

    Roč. 23, č. 145 (2004), s. 471-479 ISSN 0165-0114 R&D Projects: GA ČR GA402/04/1026 Institutional research plan: CEZ:AV0Z1075907 Keywords : triangular norm * triangular conorm * aggregation operator Subject RIV: BA - General Mathematics Impact factor: 0.734, year: 2004

  6. Distributional chaos for triangular maps

    International Nuclear Information System (INIS)

    Smital, Jaroslav; Stefankova, Marta

    2004-01-01

    In this paper we exhibit a triangular map F of the square with the following properties: (i) F is of type 2 ∞ but has positive topological entropy; we recall that similar example was given by Kolyada in 1992, but our argument is much simpler. (ii) F is distributionally chaotic in the wider sense, but not distributionally chaotic in the sense introduced by Schweizer and Smital [Trans. Amer. Math. Soc. 344 (1994) 737]. In other words, there are lower and upper distribution functions PHI xy and PHI xy * generated by F such that PHI xy * ≡1 and PHI xy (0 + ) uv , and PHI uv * such that PHI uv * ≡1 and PHI uv (t)=0 whenever 0 0. We also show that the two notions of distributional chaos used in the paper, for continuous maps of a compact metric space, are invariants of topological conjugacy

  7. Opening the Door on Triangular Numbers

    Science.gov (United States)

    McMartin, Kimberley; McMaster, Heather

    2016-01-01

    As an alternative to looking solely at linear functions, a three-lesson learning progression developed for Year 6 students that incorporates triangular numbers to develop children's algebraic thinking is described and evaluated.

  8. Decarbonization Wedges. November 2015. Report

    International Nuclear Information System (INIS)

    Alazard-Toux, N.; Criqui, P.; Devezeaux de Lavergne, J.G.; Chevallet, L.; Gentier, S.; Hache, E.; Le Net, E.; Menanteau, Ph.; Thais, Fr.; Achard, JL.; Allard, Fr.; Authier, O.; Babarit, A.; Badin, Fr.; Bazile, F.; Bernard, O.; Birat, JP.; Brault, P.; Burnol, A.; Carre, Fr.; Delrue, F.; Dufour, A.; Duplan, JL.; Durand, P.; Duval, O.; Fabriol, H.; Ferrant, P.; Flamant, G.; Forti, L.; Garnier, J.; Gimenez, M.; Goyeneche, O.; Hadj Said, N.; Jasserand, Fr.; Kalaydjian, F.; Le Boulluec, M.; Legrand, J.; Lorne, D.; Lucchese, P.; Magand, S.; Malbranche, Ph.; Mermillod, N.; Monot, F.; Olivier, B.; Pacaud, P.; Papillon, Ph.; Ponsot-Jacquin, C.; Quenard, D.; Rachez, X.; Rapin, M.; Rocher, Ph.; Sanjuan, B.; Sauvant-Moynot, V.; Tilagone, R.; Vinot, S.; Berthomieu, R.; Vajnovszki, A.

    2015-01-01

    2015 is a particularly eventful year in the field of energy. From 30 November through 11 December, France will host the 21. Conference of the Parties on Climate Change (COP21) in Paris. The expectations for this international event are high. Its main goal is to obtain an agreement to keep global warming below 2 deg. C by securing a set of voluntary commitments from the various countries and regions of the world to reduce global greenhouse gas emissions and by mobilizing $100 billion per year from 2020 onwards to finance climate change policies, especially in developing countries. In France, the year 2015 was also marked by the adoption of the Energy Transition and Green Growth Act that set a course and defined a road-map, through a set of objectives, aimed at helping our country reduce its CO 2 emissions in the field of energy. In this context, ANCRE (French National Alliance for Energy Research Coordination) would like to reiterate the major role of energy research and innovation in reducing anthropogenic (i.e. human induced) greenhouse gas emissions through research conducted on decarbonization wedges, a key technology in the fight against climate change in the field of energy on a planetary scale. Limiting the temperature increase on the earth's surface to 2 deg. C by 2100 is a challenging target, but it could be achievable with the rapid, sustained development and wide dissemination of a broad set of technologies. However, to achieve this goal, it is indispensable to conduct research aimed at speeding up low carbon technologies deployment and at reducing their cost. Through this joint report to which numerous researchers and experts contributed, ANCRE wishes to continue its efforts to build a global strategic vision that an Alliance comprising nearly 19 different research institutions can provide. This study follows the work conducted on energy transition scenarios for France and the road-maps drawn up by the ten programmatic groups structuring the

  9. On some labelings of triangular snake and central graph of triangular snake graph

    Science.gov (United States)

    Agasthi, P.; Parvathi, N.

    2018-04-01

    A Triangular snake Tn is obtained from a path u 1 u 2 … u n by joining ui and u i+1 to a new vertex wi for 1≤i≤n‑1. A Central graph of Triangular snake C(T n ) is obtained by subdividing each edge of Tn exactly once and joining all the non adjacent vertices of Tn . In this paper the ways to construct square sum, square difference, Root Mean square, strongly Multiplicative, Even Mean and Odd Mean labeling for Triangular Snake and Central graph of Triangular Snake graphs are reported.

  10. Comparing virtual with physical wedge for the transmission factors

    International Nuclear Information System (INIS)

    Lin Kuei-Hua; Lin Jao-Perng; Chu Tieh-Chi; Liu Mu-Tai

    2000-01-01

    This paper investigates the discrepancies between virtual wedge and physical wedge at the standard wedge angles of 15, 30, 45, and 60 degrees. The dose distributions for virtual wedge and physics wedge were measured by using a commercial multichamber detector array. The transmission factors of each virtual wedge and physical wedge were measured for Siemens PRIMUS 3008 linear accelerator by single ion chamber. These factors were used to set-up the clinical treatment data tables for clinical dosimetry for virtual wedge utilization. The Wellhoefer IC15, 0.13cc chamber was installed on the chamber frame of Wellhoefer water phantom (48x48x40 cm 3 ). The surface of water was at 100 cm SSD. The output factor in water were measured on the central axis of each field at 5 cm depth for 6MV or 10 cm depth for 15MV X-ray on virtual wedge and physical wedge. Comparing virtual wedge with physical wedge for transmission factor as field size range from 4x4 to 25x25 cm 2 . We have measured the dose distributions using the chamber array for 25x25 cm 2 virtual wedge fields and physical wedge fields at wedge angles of 15deg to 60deg. The dose profiles at various depths were also measured using the chamber array. The transmission factors of each physical wedge were slowly increased as field sizes increase, and had different value for each wedge angle. The transmission factors of each virtual wedge were almost constant value as 1.0 for each wedge angle. The results show that the dose profiles including the penumbra dose measured by the chamber array for virtual wedge agree with those measured for the physical wedge. For transmission factors of virtual wedge were constant value as 1.0 for each angles, namely output without wedge is almost equal to output with wedge on the central axis. Virtual wedge has practical and dosimetric advantages over physical wedge. (author)

  11. Dosimetry and clinical implementation of dynamic wedge

    International Nuclear Information System (INIS)

    Klein, Eric E.; Low, Daniel A.; Meigooni, Ali S.; Purdy, James A.

    1995-01-01

    Purpose: Wedge-shaped isodoses are desired in a number of clinical situations. Physical wedge filters have provided nominal angled isodoses with dosimetric consequences of beam hardening, increased peripheral dosing, nonidealized gradients at deep depths, along with the practical consequences of filter handling and placement problems. Dynamic wedging uses a combination of a moving jaw and changing dose rate to achieve angled isodoses. The clinical implementation of dynamic wedge and an accompanying quality assurance program are discussed in detail. Methods and Materials: The accelerator at our facility has two photon energies (6 MV and 18 MV), currently with dynamic wedge angles of 15 deg. , 30 deg. , 45 deg. , and 60 deg. . The segmented treatment tables (STT) that drive the jaw in concert with a changing dose rate are unique for field sizes ranging from 4.0 cm to 20.0 cm in 05 cm steps, resulting in 256 STTs. Transmission wedge factors were measured for each STT with an ion chamber. Isodose profiles were accumulated with film after dose conversion. For treatment-planning purposes, d max orthogonal dose profiles were measured for open and dynamic fields. Physical filters were assigned empirically via the ratio of open and wedge profiles. Results: A nonlinear relationship with wedge factor and field size was found. The factors were found to be independent of the stationary field setting or second order blocking. Dynamic wedging provided more consistent gradients across the field compared with physical filters. Percent depth doses were found to be closer to open field. The created physical filters provided planned isodoses that closely resembled measured isodoses. Comparative isodose plans show improvement with dynamic wedging. Conclusions: Dynamic weding has practical and dosimetric advantages over physical filters. Table collisions with physical filters are alleviated. Treatment planning has been solved with an empirical solution. Dynamic wedge is a positive

  12. Chemical lift-off of (11-22) semipolar GaN using periodic triangular cavities

    Science.gov (United States)

    Jeon, Dae-Woo; Lee, Seung-Jae; Jeong, Tak; Baek, Jong Hyeob; Park, Jae-Woo; Jang, Lee-Woon; Kim, Myoung; Lee, In-Hwan; Ju, Jin-Woo

    2012-01-01

    Chemical lift-off of (11-22) semipolar GaN using triangular cavities was investigated. The (11-22) semipolar GaN was grown using epitaxial lateral overgrowth by metal-organic chemical vapor deposition on m-plane sapphire, in such a way as to keep N terminated surface of c-plane GaN exposed in the cavities. After regrowing 300 μm thick (11-22) semipolar GaN by hydride vapor phase epitaxy for a free-standing (11-22) semipolar GaN substrate, the triangular cavities of the templates were chemically etched in molten KOH. The (000-2) plane in the triangular cavities can be etched in the [0002] direction with the high lateral etching rate of 196 μm/min. The resulting free-standing (11-22) semipolar GaN substrate was confirmed to be strain-free by the Raman analysis.

  13. 2-D modeling of dual-mode acoustic phonon excitation of a triangular nanoplate

    International Nuclear Information System (INIS)

    Tai, Po-Tse; Yu, Pyng; Tang, Jau

    2010-01-01

    Graphical abstract: Modeling the lattice dynamics of a triangular plate with the arrows indicating the direction of impulsive thermal stress. We investigated ultrafast structural dynamics of triangular nanoplates based on 2-D Fermi-Pasta-Ulam model to explain coherent acoustic phonon excitation in nanoprisms. - Abstract: In this theoretical work, we investigated coherent phonon excitation of a triangular nanoplate based on 2-D Fermi-Pasta-Ulam lattice model. Based on the two-temperature model commonly used in description of laser heating of metals, we considered two kinds of forces related to electronic and lattice stresses. Based on extensive simulation and analysis, we identified two major planar phonon modes, namely, a standing wave mode related to the triangle bisector and another mode corresponding to half of the side length. This work elucidates the roles of laser-induced electronic stress and lattice stress in controlling the initial phase and the amplitude ratio between these two phonon modes.

  14. Measurement of hepatic venous pressure gradient revisited: Catheter wedge vs balloon wedge techniques

    Directory of Open Access Journals (Sweden)

    S Timothy Chelliah

    2011-01-01

    Full Text Available Aims: To evaluate the accuracy of measurement of hepatic venous pressure gradient by catheter wedge as compared to balloon wedge (the gold standard. Materials and Methods: Forty-five patients having a clinical diagnosis of intrahepatic portal hypertension were subjected to the two different types of pressure measurements (catheter wedge and balloon wedge during transjugular liver biopsy under fluoroscopic guidance. Statistical Analysis: Spearman′s rank correlation coefficient, Bland-Altman plot for agreement, and single measure intraclass correlation were used for analysis of data. Results: There was a close correlation between the results obtained by both the techniques, with highly significant concordance (P < 0.0001. Hepatic venous pressure gradients as measured by the catheter wedge technique were either equal to or less than those obtained by the balloon wedge technique. Conclusions: The difference in hepatic venous pressure gradients measured by the two techniques is insignificant.

  15. Strange distributionally chaotic triangular maps II

    International Nuclear Information System (INIS)

    Paganoni, L.; Smital, J.

    2006-01-01

    The notion of distributional chaos was introduced by Schweizer and Smital [Measures of chaos and a spectral decomposition of dynamical systems on the interval, Trans Am Math Soc 1994;344:737-854] for continuous maps of the interval. For continuous maps of a compact metric space three mutually non-equivalent versions of distributional chaos, DC1-DC3, can be considered. In this paper we study distributional chaos in the class T m of triangular maps of the square which are monotone on the fibres. The main results: (i) If F-bar T m has positive topological entropy then F is DC1, and hence, DC2 and DC3. This result is interesting since similar statement is not true for general triangular maps of the square [Smital and Stefankova, Distributional chaos for triangular maps, Chaos, Solitons and Fractals 2004;21:1125-8]. (ii) There are F 1 ,F 2 -bar T m which are not DC3, and such that not every recurrent point of F 1 is uniformly recurrent, while F 2 is Li and Yorke chaotic on the set of uniformly recurrent points. This, along with recent results by Forti et al. [Dynamics of homeomorphisms on minimal sets generated by triangular mappings, Bull Austral Math Soc 1999;59:1-20], among others, make possible to compile complete list of the implications between dynamical properties of maps in T m , solving a long-standing open problem by Sharkovsky

  16. Basic Employability Skills: A Triangular Design Approach

    Science.gov (United States)

    Rosenberg, Stuart; Heimler, Ronald; Morote, Elsa-Sofia

    2012-01-01

    Purpose: This paper seeks to examine the basic employability skills needed for job performance, the reception of these skills in college, and the need for additional training in these skills after graduation. Design/methodology/approach: The research was based on a triangular design approach, in which the attitudes of three distinct groups--recent…

  17. A microscopic model of triangular arbitrage

    Science.gov (United States)

    Aiba, Yukihiro; Hatano, Naomichi

    2006-11-01

    We introduce a microscopic model which describes the dynamics of each dealer in multiple foreign exchange markets, taking account of the triangular arbitrage transaction. The model reproduces the interaction among the markets well. We explore the relation between the parameters of the present microscopic model and the spring constant of a macroscopic model that we proposed previously.

  18. Triangular tube proportional wire chamber system

    Energy Technology Data Exchange (ETDEWEB)

    Badtke, D H; Bakken, J A; Barnett, B A; Blumenfeld, B J; Chien, C Y; Madansky, L; Matthews, J A.J.; Pevsner, A; Spangler, W J [Johns Hopkins Univ., Baltimore, MD (USA); Lee, K L [California Univ., Berkeley (USA). Lawrence Berkeley Lab.

    1981-10-15

    We report on the characteristics of the proportional tube chamber system which has been constructed for muon identification in the PEP-4 experiment at SLAC. The mechanical and electrical properties of the extruded aluminum triangular tubes allow these detectors to be used as crude drift chambers.

  19. Use of Wedge Absorbers in MICE

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, D. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Summers, D. [Univ. of Mississippi, Oxford, MS (United States); Mohayai, T. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); IIT, Chicago, IL (United States); Snopok, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); IIT, Chicago, IL (United States); Rogers, C. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL)

    2017-03-01

    Wedge absorbers are needed to obtain longitudinal cooling in ionization cooling. They also can be used to obtain emittance exchanges between longitudinal and transverse phase space. There can be large exchanges in emittance, even with single wedges. In the present note we explore the use of wedge absorbers in the MICE experiment to obtain transverse–longitudinal emittance exchanges within present and future operational conditions. The same wedge can be used to explore “direct” and “reverse” emittance exchange dynamics, where direct indicates a configuration that reduces momentum spread and reverse is a configuration that increases momentum spread. Analytical estimated and ICOOL and G4BeamLine simulations of the exchanges at MICE parameters are presented. Large exchanges can be obtained in both reverse and direct configurations.

  20. A Wedge Absorber Experiment at MICE

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David [Fermilab; Mohayai, Tanaz [IIT, Chicago; Rogers, Chris [Rutherford; Snopok, Pavel [IIT, Chicago; Summers, Don [Mississippi U.

    2017-05-01

    Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.

  1. Inclined indentation of smooth wedge in rock mass

    Science.gov (United States)

    Chanyshev, AI; Podyminogin, GM; Lukyashko, OA

    2018-03-01

    The article focuses on the inclined rigid wedge indentation into a rigid-plastic half-plane of rocks with the Mohr–Coulomb-Mohr plasticity. The limiting loads on different sides of the wedge are determined versus the internal friction angle, cohesion and wedge angle. It is shown that when the force is applied along the symmetry axis of the wedge, the zone of plasticity is formed only on one wedge side. In order to form the plasticity zone on both sides of the wedge, it is necessary to apply the force asymmetrically relative to the wedge symmetry axis. An engineering solution for the asymmetrical case implementation is suggested.

  2. Studying wedge factors and beam profiles for physical and enhanced dynamic wedges

    Directory of Open Access Journals (Sweden)

    Ahmad Misbah

    2010-01-01

    Full Text Available This study was designed to investigate variation in Varian′s Physical and Enhanced Dynamic Wedge Factors (WF as a function of depth and field size. The profiles for physical wedges (PWs and enhanced dynamic wedges (EDWs were also measured using LDA-99 array and compared for confirmation of EDW angles at different depths and field sizes. WF measurements were performed in water phantom using cylindrical 0.66 cc ionization chamber. WF was measured by taking the ratio of wedge and open field ionization data. A normalized wedge factor (NWF was introduced to circumvent large differences between wedge factors for different wedge angles. A strong linear dependence of PW Factor (PWF with depth was observed. Maximum variation of 8.9% and 4.1% was observed for 60° PW with depth at 6 and 15 MV beams respectively. The variation in EDW Factor (EDWF with depth was almost negligible and less than two per cent. The highest variation in PWF as a function of field size was 4.1% and 3.4% for thicker wedge (60° at 6 and 15 MV beams respectively and decreases with decreasing wedge angle. EDWF shows strong field size dependence and significant variation was observed for all wedges at both photon energies. Differences in profiles between PW and EDW were observed on toe and heel sides. These differences were dominant for larger fields, shallow depths, thicker wedges and low energy beam. The study indicated that ignoring depth and field size dependence of WF may result in under/over dose to the patient especially doing manual point dose calculation.

  3. Mantle wedge serpentinization effects on slab dips

    Directory of Open Access Journals (Sweden)

    Eh Tan

    2017-01-01

    Full Text Available The mechanical coupling between a subducting slab and the overlying mantle wedge is an important factor in controlling the subduction dip angle and the flow in mantel wedge. This paper investigates the role of the amount of mantle serpentinization on the subduction zone evolution. With numerical thermos-mechanical models with elasto-visco-plastic rheology, we vary the thickness and depth extent of mantle serpentinization in the mantle wedge to control the degree of coupling between the slab and mantle wedge. A thin serpentinized mantle layer is required for stable subduction. For models with stable subduction, we find that the slab dip is affected by the down-dip extent and the mantle serpentinization thickness. A critical down-dip extent exists in mantle serpentinization, determined by the thickness of the overriding lithosphere. If the down-dip extent does not exceed the critical depth, the slab is partially coupled to the overriding lithosphere and has a constant dip angle regardless of the mantle serpentinization thickness. However, if the down-dip extent exceeds the critical depth, the slab and the base of the overriding lithosphere would be separated and decoupled by a thick layer of serpentinized peridotite. This allows further slab bending and results in steeper slab dip. Increasing mantle serpentinization thickness will also result in larger slab dip. We also find that with weak mantle wedge, there is no material flowing from the asthenosphere into the serpentinized mantle wedge. All of these results indicate that serpentinization is an important ingredient when studying the subduction dynamics in the mantle wedge.

  4. Optical dating of relict sand wedges and composite-wedge pseudomorphs in Flanders, Belgium

    DEFF Research Database (Denmark)

    Buylaert, Jan-Pieter; Ghysels, Günther; Murray, Andrew S.

    2009-01-01

    We report on quartz Optically Stimulated Luminescence (OSL) dating of the infill of 14 relict sand wedges and composite-wedge pseudomorphs at 5 different sites in Flanders, Belgium. A laboratory dose recovery test indicates that the single-aliquot regenerative-dose (SAR) procedure is suitable for...

  5. Double Exponential Instability of Triangular Arbitrage Systems

    OpenAIRE

    Cross, Rod; Kozyakin, Victor

    2012-01-01

    If financial markets displayed the informational efficiency postulated in the efficient markets hypothesis (EMH), arbitrage operations would be self-extinguishing. The present paper considers arbitrage sequences in foreign exchange (FX) markets, in which trading platforms and information are fragmented. In Kozyakin et al. (2010) and Cross et al. (2012) it was shown that sequences of triangular arbitrage operations in FX markets containing 4 currencies and trader-arbitrageurs tend to display p...

  6. Innovative wedge axe in making split firewood

    International Nuclear Information System (INIS)

    Mutikainen, A.

    1998-01-01

    Interteam Oy, a company located in Espoo, has developed a new method for making split firewood. The tools on which the patented System Logmatic are based are wedge axe and cylindrical splitting-carrying frame. The equipment costs about 495 FIM. The block of wood to be split is placed inside the upright carrying frame and split in a series of splitting actions using the innovative wedge axe. The finished split firewood remains in the carrying frame, which (as its name indicates) also serves as the means for carrying the firewood. This innovative wedge-axe method was compared with the conventional splitting of wood using an axe (Fiskars -handy 1400 splitting axe costing about 200 FIM) in a study conducted at TTS-Institute. There were eight test subjects involved in the study. In the case of the wedge-axe method, handling of the blocks to be split and of the finished firewood was a little quicker, but in actual splitting it was a little slower than the conventional axe method. The average productivity of splitting the wood and of the work stages related to it was about 0.4 m 3 per effective hour in both methods. The methods were also equivalent of one another in terms of the load imposed by the work when measured in terms of the heart rate. As regards work safety, the wedge-axe method was superior to the conventional method, but the continuous striking action and jolting transmitted to the arms were unpleasant (orig.)

  7. Tailoring graphene magnetism by zigzag triangular holes: A first-principles thermodynamics study

    Directory of Open Access Journals (Sweden)

    Muhammad Ejaz Khan

    2016-03-01

    Full Text Available We discuss the thermodynamic stability and magnetic property of zigzag triangular holes (ZTHs in graphene based on the results of first-principles density functional theory calculations. We find that ZTHs with hydrogen-passivated edges in mixed sp2/sp3 configurations (z211 could be readily available at experimental thermodynamic conditions, but ZTHs with 100% sp2 hydrogen-passivation (z1 could be limitedly available at high temperature and ultra-high vacuum conditions. Graphene magnetization near the ZTHs strongly depends on the type and the size of the triangles. While metallic z1 ZTHs exhibit characteristic edge magnetism due to the same-sublattice engineering, semiconducting z211 ZTHs do show characteristic corner magnetism when the size is small <2 nm. Our findings could be useful for experimentally tailoring metal-free carbon magnetism by simply fabricating triangular holes in graphene.

  8. Multiple Fano-Like MIM Plasmonic Structure Based on Triangular Resonator for Refractive Index Sensing.

    Science.gov (United States)

    Jankovic, Nikolina; Cselyuszka, Norbert

    2018-01-19

    In this paper, we present a Fano metal-insulator-metal (MIM) structure based on an isosceles triangular cavity resonator for refractive index sensing applications. Due to the specific feeding scheme and asymmetry introduced in the triangular cavity, the resonator exhibits four sharp Fano-like resonances. The behavior of the structure is analyzed in detail and its sensing capabilities demonstrated through the responses for various refractive indices. The results show that the sensor has very good sensitivity and maximal figure of merit (FOM) value of 3.2 × 10⁵. In comparison to other similar sensors, the proposed one has comparable sensitivity and significantly higher FOM, which clearly demonstrates its high sensing potential.

  9. Convolution-wedge product of fields

    International Nuclear Information System (INIS)

    Diep, D.N.; Duc, D.V.; Tan, H.V.; Viet, N.A.

    2007-07-01

    In this paper we use the pair of electric-magnetic (or GNO, or Langlands) duality groups G = Sp(1) and L G = SO(3) and the T-transformation in mirror symmetry (or the S-duality, or the Fourier-Mukai transformation) to define the wedge product of fields: first by using gauge transformation, we reduce the fields with values in LieG = sp(1) to the fields with values in the Lie algebra of the maximal torus t subset of LieG = sp(1). Next we use the Fourier-Mukai transformation of fields to have the images as fields with values in the Lie algebra of the Langlands dual torus L t in Lie L G = so(3). The desired wedge product of two fields is defined as the pre-image of the ordinary wedge product of images with values in L t subset of so(3). (author)

  10. Diffraction by an immersed elastic wedge

    CERN Document Server

    Croisille, Jean-Pierre

    1999-01-01

    This monograph presents the mathematical description and numerical computation of the high-frequency diffracted wave by an immersed elastic wave with normal incidence. The mathematical analysis is based on the explicit description of the principal symbol of the pseudo-differential operator connected with the coupled linear problem elasticity/fluid by the wedge interface. This description is subsequently used to derive an accurate numerical computation of diffraction diagrams for different incoming waves in the fluid, and for different wedge angles. The method can be applied to any problem of coupled waves by a wedge interface. This work is of interest for any researcher concerned with high frequency wave scattering, especially mathematicians, acousticians, engineers.

  11. The design of a new JET divertor for high triangularity and high current scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Chappuis, P. E-mail: philippe.chappuis@cea.fr; Damiani, C.; Guerin, C.; Hurd, F.; Loarte, A.; Lomas, P.; Lorenz, A.; Pamela, J.; Peacock, A.; Portafaix, C.; Rapp, J.; Riccardo, V.; Rimini, F.; Saibene, G.; Salavy, J.F.; Sauce, Y.; Sartori, R.; Solano, E.; Thomas, E.; Thomas, P.; Tsitrone, E.; Valeta, M.P

    2003-09-01

    A new divertor (MKII-HP) has been designed to be implemented in JET as part of a possible enhancement programme of the JET facility (JET EP). The aim is to handle up to 40 MW of injected power for 10 s with plasma triangularities up to 0.5 while keeping enough flexibility for other scenarios. The divertor is shaped to optimise the wetting fraction without exposing sharp edges or metallic parts and the general design allows for high halo currents.

  12. Coupling effect of topological states and Chern insulators in two-dimensional triangular lattices

    Science.gov (United States)

    Zhang, Jiayong; Zhao, Bao; Xue, Yang; Zhou, Tong; Yang, Zhongqin

    2018-03-01

    We investigate topological states of two-dimensional (2D) triangular lattices with multiorbitals. Tight-binding model calculations of a 2D triangular lattice based on px and py orbitals exhibit very interesting doubly degenerate energy points at different positions (Γ and K /K' ) in momentum space, with quadratic non-Dirac and linear Dirac band dispersions, respectively. Counterintuitively, the system shows a global topologically trivial rather than nontrivial state with consideration of spin-orbit coupling due to the "destructive interference effect" between the topological states at the Γ and K /K' points. The topologically nontrivial state can emerge by introducing another set of triangular lattices to the system (bitriangular lattices) due to the breakdown of the interference effect. With first-principles calculations, we predict an intrinsic Chern insulating behavior (quantum anomalous Hall effect) in a family of the 2D triangular lattice metal-organic framework of Co(C21N3H15) (TPyB-Co) from this scheme. Our results provide a different path and theoretical guidance for the search for and design of new 2D topological quantum materials.

  13. Irradiation of parametria by double-wedge

    International Nuclear Information System (INIS)

    Weisz, Csaba; Katona, Ernoe; Zarand, Pal; Polgar, Istvan; Nemeth, Gyoergy

    1984-01-01

    The dose distribution of a cobalt unit modified with a double-wedge as well as its combination with intracavitary radiotherapy was investigated. The measurements were made in both Alderson-Rando and wather phantom by using film densitometry, thermoluminescence dosimetry and ionization chambers. The dose distribution calculated on the basis of the Van de Geij program was in good agreement with the measurements. A homogeneous irradiation of the parametria can be obtained by using a combination of intracavitary and external double-wedge irradiation. (author)

  14. The asc trinodal platform: Two-step assembly of triangular, tetrahedral, and trigonal-prismatic molecular building blocks

    KAUST Repository

    Schoedel, Alexander; Cairns, Amy; Belmabkhout, Youssef; Wojtas, Łukasz; Mohamed, Mona Hassan; Zhang, ZhenJie; Proserpio, Davide Maria; Eddaoudi, Mohamed; Zaworotko, Michael J.

    2013-01-01

    The self-assembly of triangular, tetrahedral, and trigonal-prismatic molecular building blocks affords the first example of a trinodal family of metal-organic materials. Four examples of isoreticular expanded and functionalized frameworks are detailed. Gas adsorption experiments validated the permanent porosity of the parent structure. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. The asc trinodal platform: Two-step assembly of triangular, tetrahedral, and trigonal-prismatic molecular building blocks

    KAUST Repository

    Schoedel, Alexander

    2013-02-10

    The self-assembly of triangular, tetrahedral, and trigonal-prismatic molecular building blocks affords the first example of a trinodal family of metal-organic materials. Four examples of isoreticular expanded and functionalized frameworks are detailed. Gas adsorption experiments validated the permanent porosity of the parent structure. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. MR Imaging of the Triangular Fibrocartilage Complex.

    Science.gov (United States)

    Cody, Michael E; Nakamura, David T; Small, Kirstin M; Yoshioka, Hiroshi

    2015-08-01

    MR imaging has emerged as the mainstay in imaging internal derangement of the soft tissues of the musculoskeletal system largely because of superior contrast resolution. The complex geometry and diminutive size of the triangular fibrocartilage complex (TFCC) and its constituent structures can make optimal imaging of the TFCC challenging; therefore, production of clinically useful images requires careful optimization of image acquisition parameters. This article provides a foundation for advanced TFCC imaging including factors to optimize magnetic resonance images, arthrography, detailed anatomy, and classification of injury. In addition, clinical presentations and treatments for TFCC injury are briefly considered. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Arthroscopic-Assisted Triangular Fibrocartilage Complex Reconstruction.

    Science.gov (United States)

    Chu-Kay Mak, Michael; Ho, Pak-Cheong

    2017-11-01

    Injury of the triangular fibrocartilage complex (TFCC) is a common cause of ulnar-sided wrist pain. Volar and dorsal radioulnar ligaments and their foveal insertion are the most important stabilizing components of the TFCC. In irreparable tears, anatomic reconstruction of the TFCC aims to restore normal biomechanics and stability of the distal radioulnar joint. We proposed a novel arthroscopic-assisted technique using a palmaris longus tendon graft. Arthroscopic-assisted TFCC reconstruction is a safe and effective approach with outcomes comparable to conventional open reconstruction and may result in a better range of motion from minimizing soft tissue dissection and subsequent scarring. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Electromagnetic field scattering by a triangular aperture.

    Science.gov (United States)

    Harrison, R E; Hyman, E

    1979-03-15

    The multiple Laplace transform has been applied to analysis and computation of scattering by a double triangular aperture. Results are obtained which match far-field intensity distributions observed in experiments. Arbitrary polarization components, as well as in-phase and quadrature-phase components, may be determined, in the transform domain, as a continuous function of distance from near to far-field for any orientation, aperture, and transformable waveform. Numerical results are obtained by application of numerical multiple inversions of the fully transformed solution.

  19. Are Pericentric Inversions Reorganizing Wedge Shell Genomes?

    Directory of Open Access Journals (Sweden)

    Daniel García-Souto

    2017-12-01

    Full Text Available Wedge shells belonging to the Donacidae family are the dominant bivalves in exposed beaches in almost all areas of the world. Typically, two or more sympatric species of wedge shells differentially occupy intertidal, sublittoral, and offshore coastal waters in any given locality. A molecular cytogenetic analysis of two sympatric and closely related wedge shell species, Donax trunculus and Donax vittatus, was performed. Results showed that the karyotypes of these two species were both strikingly different and closely alike; whilst metacentric and submetacentric chromosome pairs were the main components of the karyotype of D. trunculus, 10–11 of the 19 chromosome pairs were telocentric in D. vittatus, most likely as a result of different pericentric inversions. GC-rich heterochromatic bands were present in both species. Furthermore, they showed coincidental 45S ribosomal RNA (rRNA, 5S rRNA and H3 histone gene clusters at conserved chromosomal locations, although D. trunculus had an additional 45S rDNA cluster. Intraspecific pericentric inversions were also detected in both D. trunculus and D. vittatus. The close genetic similarity of these two species together with the high degree of conservation of the 45S rRNA, 5S rRNA and H3 histone gene clusters, and GC-rich heterochromatic bands indicate that pericentric inversions contribute to the karyotype divergence in wedge shells.

  20. Quench propagation across the copper wedges in SSC dipoles

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Robins, K.E.; Sampson, W.B.

    1986-01-01

    The effect of copper wedges on quench propagation in SSC windings has been studied. The results indicate that the turn-to-turn quench transit time for conductors separated by an insulated copper wedge can be predicted with reasonable accuracy from the bulk quench properties and the mean wedge thickness

  1. 49 CFR 215.113 - Defective plain bearing wedge.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Defective plain bearing wedge. 215.113 Section 215... Suspension System § 215.113 Defective plain bearing wedge. A railroad may not place or continue in service a car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not located...

  2. Contralateral breast dose reduction using a virtual wedge

    International Nuclear Information System (INIS)

    Yeo, In Hwan; Kim, Dae Yong; Kim, Tae Hyun; Shin, Kyung Hwan; Chie, Eui Kyu; Park, Won; Lim, Do Hoon; Huh, Seung Jae; Ahn, Yong Chan

    2005-01-01

    To evaluate the contralateral breast dose using a virtual wedge compared with that using a physical wedge and an open beam in a Siemens linear accelerator. The contralateral breast dose was measured using diodes placed on a humanoid phantom. Diodes were placed at 5.5 cm (position 1), 9.5 cm (position 2), and 14 cm (position 3) along the medial-lateral line from the medial edge of the treatment field. A 6-MV photon beam was used with tangential irradiation technique at 50 and 230 degrees of gantry angle. Asymmetrically collimated 17 x 10 cm field was used. For the first set of experiment, four treatment set-ups were used, which were an open medial beam with a 30-degree wedged lateral beam (physical and virtual wedges, respectively) and a 15-degree wedge medial beam with a 15-degree wedged lateral beam (physical and virtual wedges, respectively). The second set of experiment consists of setting with medial beam without wedge, a 15-degree wedge, and a 60-degree wedge (physical and virtual wedges, respectively). Identical monitor units were delivered. Each set of experiment was repeated for three times. In the first set of experiment, the contralateral breast dose was the highest at the position 1 and decreased in order of the position 2 and 3. The contralateral breast dose was reduced with open beam on the medial side (2.70± 1.46%) compared to medial beam with a wedge (both physical and virtual) (3.25 ± 1.59%). The differences were larger with a physical wedge (0.99 ± 0.18%) than a virtual wedge (0.10 ± 0.01%) at all positions. The use of a virtual wedge reduced the contralateral breast dose by 0.12% to 1.20% of the prescribed dose compared to a physical wedge with same technique. In the second experiment, the contralateral breast dose decreased in order of the open beam, the virtual wedge, and the physical wedge at the position 1, and it decreased in order of a physical wedge, an open beam, and a virtual wedge at the position 2 and 3. The virtual wedge equipped

  3. Higher-n triangular dilatonic black holes

    Science.gov (United States)

    Zadora, Anton; Gal'tsov, Dmitri V.; Chen, Chiang-Mei

    2018-04-01

    Dilaton gravity with the form fields is known to possess dyon solutions with two horizons for the discrete "triangular" values of the dilaton coupling constant a =√{ n (n + 1) / 2 }. This sequence first obtained numerically and then explained analytically as consequence of the regularity of the dilaton, should have some higher-dimensional and/or group theoretical origin. Meanwhile, this origin was explained earlier only for n = 1 , 2 in which cases the solutions were known analytically. We extend this explanation to n = 3 , 5 presenting analytical triangular solutions for the theory with different dilaton couplings a , b in electric and magnetic sectors in which case the quantization condition reads ab = n (n + 1) / 2. The solutions are derived via the Toda chains for B2 and G2 Lie algebras. They are found in the closed form in general D space-time dimensions. Solutions satisfy the entropy product rules indicating on the microscopic origin of their entropy and have negative binding energy in the extremal case.

  4. Redesigning Triangular Dense Matrix Computations on GPUs

    KAUST Repository

    Charara, Ali

    2016-08-09

    A new implementation of the triangular matrix-matrix multiplication (TRMM) and the triangular solve (TRSM) kernels are described on GPU hardware accelerators. Although part of the Level 3 BLAS family, these highly computationally intensive kernels fail to achieve the percentage of the theoretical peak performance on GPUs that one would expect when running kernels with similar surface-to-volume ratio on hardware accelerators, i.e., the standard matrix-matrix multiplication (GEMM). The authors propose adopting a recursive formulation, which enriches the TRMM and TRSM inner structures with GEMM calls and, therefore, reduces memory traffic while increasing the level of concurrency. The new implementation enables efficient use of the GPU memory hierarchy and mitigates the latency overhead, to run at the speed of the higher cache levels. Performance comparisons show up to eightfold and twofold speedups for large dense matrix sizes, against the existing state-of-the-art TRMM and TRSM implementations from NVIDIA cuBLAS, respectively, across various GPU generations. Once integrated into high-level Cholesky-based dense linear algebra algorithms, the performance impact on the overall applications demonstrates up to fourfold and twofold speedups, against the equivalent native implementations, linked with cuBLAS TRMM and TRSM kernels, respectively. The new TRMM/TRSM kernel implementations are part of the open-source KBLAS software library (http://ecrc.kaust.edu.sa/Pages/Res-kblas.aspx) and are lined up for integration into the NVIDIA cuBLAS library in the upcoming v8.0 release.

  5. Limits of commutative triangular systems on locally compact groups

    Indian Academy of Sciences (India)

    Commutative triangular systems of probability measures on locally compact groups have been studied extensively and ... in [S3,S4], we extend our earlier result to some particular triangular systems on algebraic groups. We also discuss ..... Now G can be embedded as a closed subgroup in. G2 ¼ G1=D and G0. 2 ¼ ًG0 آ ...

  6. Triangular Diagrams Teach Steady and Dynamic Behaviour of Catalytic Reactions.

    Science.gov (United States)

    Klusacek, K.; And Others

    1989-01-01

    Illustrates how triangular diagrams can aid in presenting some of the rather complex transient interactions that occur among gas and surface species during heterogeneous catalytic reactions. The basic equations and numerical examples are described. Classroom use of the triangular diagram is discussed. Several diagrams and graphs are provided. (YP)

  7. Sorption of Triangular Silver Nanoplates on Polyurethane Foam

    Science.gov (United States)

    Furletov, A. A.; Apyari, V. V.; Garshev, A. V.; Volkov, P. A.; Tolmacheva, V. V.; Dmitrienko, S. G.

    2018-02-01

    The sorption of triangular silver nanoplates on polyurethane foam is investigated as a procedure for creating a nanocomposite sensing material for subsequent use in optical means of chemical analysis. Triangular silver nanoplates are synthesized and characterized, and a simple sorption technique for the formation of a composite material based on these nanoplates is proposed.

  8. New similarity of triangular fuzzy number and its application.

    Science.gov (United States)

    Zhang, Xixiang; Ma, Weimin; Chen, Liping

    2014-01-01

    The similarity of triangular fuzzy numbers is an important metric for application of it. There exist several approaches to measure similarity of triangular fuzzy numbers. However, some of them are opt to be large. To make the similarity well distributed, a new method SIAM (Shape's Indifferent Area and Midpoint) to measure triangular fuzzy number is put forward, which takes the shape's indifferent area and midpoint of two triangular fuzzy numbers into consideration. Comparison with other similarity measurements shows the effectiveness of the proposed method. Then, it is applied to collaborative filtering recommendation to measure users' similarity. A collaborative filtering case is used to illustrate users' similarity based on cloud model and triangular fuzzy number; the result indicates that users' similarity based on triangular fuzzy number can obtain better discrimination. Finally, a simulated collaborative filtering recommendation system is developed which uses cloud model and triangular fuzzy number to express users' comprehensive evaluation on items, and result shows that the accuracy of collaborative filtering recommendation based on triangular fuzzy number is higher.

  9. The observation of a triangular vortex in a rotating fluid

    NARCIS (Netherlands)

    Beckers, M.; Heijst, van G.J.F.

    1998-01-01

    A dye visualization study of a triangular vortex in a rotating fluid is presented. The emergence and subsequent break-up of the vortex structure are described. Soon after the generation of the triangular vortex it becomes unstable: two satellite vortices merge and pair with the core vortex into an

  10. Wrist stability after experimental traumatic triangular fibrocartilage complex lesions

    DEFF Research Database (Denmark)

    Munk, Bo; Jensen, Steen Lund; Olsen, Bo Sanderhoff

    2005-01-01

    The aim of this study was to evaluate changes in stability of the wrist after experimental traumatic triangular fibrocartilage complex lesions.......The aim of this study was to evaluate changes in stability of the wrist after experimental traumatic triangular fibrocartilage complex lesions....

  11. Checking the virtual treatment modality Wedge from Siemens; Verificacion de la modalidad de tratamiento virtual WEDGE de SIEMENS

    Energy Technology Data Exchange (ETDEWEB)

    Suero Rodrigo, M. A.; Marques Fraguela, E.

    2011-07-01

    The treatment modality Virtual Wedge (VW) or implemented by Siemens virtual wedge in electron linear accelerators achieved dose distributions are similar but not identical, to those obtained with physical wedges. Among the advantages against the latter is the greater ease of use, wedge factor close to one, and lower peripheral dose. However, these benefits are to be effective requires a through quality control dependence because a larger number of parameters that control the generation of the beam, the dose monitor system and the movement of the jaws of the collimator. We performed a study of the wedge taking into account different configurations that can affect their behavior from the dosimetric point of view.

  12. Mathematical model of parking space unit for triangular parking area

    Science.gov (United States)

    Syahrini, Intan; Sundari, Teti; Iskandar, Taufiq; Halfiani, Vera; Munzir, Said; Ramli, Marwan

    2018-01-01

    Parking space unit (PSU) is an effective measure for the area size of a vehicle, including the free space and the width of the door opening of the vehicle (car). This article discusses a mathematical model for parking space of vehicles in triangular shape area. An optimization model for triangular parking lot is developed. Integer Linear Programming (ILP) method is used to determine the maximum number of the PSU. The triangular parking lot is in isosceles and equilateral triangles shape and implements four possible rows and five possible angles for each field. The vehicles which are considered are cars and motorcycles. The results show that the isosceles triangular parking area has 218 units of optimal PSU, which are 84 units of PSU for cars and 134 units of PSU for motorcycles. Equilateral triangular parking area has 688 units of optimal PSU, which are 175 units of PSU for cars and 513 units of PSU for motorcycles.

  13. Magnetic focusing in triangular electron billiards

    DEFF Research Database (Denmark)

    Bøggild, Peter; Kristensen, A.; Lindelof, Poul Erik

    1999-01-01

    The classical ballistic magnetotransport in triangular electron billiards fabricated in a high mobility GaAs heterostructure has been studied at 4.2 K. The sample geometry may be viewed as a double-slit structure with a skewed injection angle. We observe a striking cancellation of the magnetic...... focusing spectrum compared to the case of a perpendicular injection angle. From numerical and analytical analysis, we confirm that the quenching is a fundamental geometrical effect, and identify two mechanisms responsible for the anomaly. The focusing spectrum of the considered skewed geometry...... is remarkably sensitive to the angular distribution of injected electrons as well as the overall injection angle. [S0163-1829(99)06619-9]....

  14. Triangular model integrating clinical teaching and assessment.

    Science.gov (United States)

    Abdelaziz, Adel; Koshak, Emad

    2014-01-01

    Structuring clinical teaching is a challenge facing medical education curriculum designers. A variety of instructional methods on different domains of learning are indicated to accommodate different learning styles. Conventional methods of clinical teaching, like training in ambulatory care settings, are prone to the factor of coincidence in having varieties of patient presentations. Accordingly, alternative methods of instruction are indicated to compensate for the deficiencies of these conventional methods. This paper presents an initiative that can be used to design a checklist as a blueprint to guide appropriate selection and implementation of teaching/learning and assessment methods in each of the educational courses and modules based on educational objectives. Three categories of instructional methods were identified, and within each a variety of methods were included. These categories are classroom-type settings, health services-based settings, and community service-based settings. Such categories have framed our triangular model of clinical teaching and assessment.

  15. Biological synthesis of triangular gold nanoprisms

    Science.gov (United States)

    Shankar, S. Shiv; Rai, Akhilesh; Ankamwar, Balaprasad; Singh, Amit; Ahmad, Absar; Sastry, Murali

    2004-07-01

    The optoelectronic and physicochemical properties of nanoscale matter are a strong function of particle size. Nanoparticle shape also contributes significantly to modulating their electronic properties. Several shapes ranging from rods to wires to plates to teardrop structures may be obtained by chemical methods; triangular nanoparticles have been synthesized by using a seeded growth process. Here, we report the discovery that the extract from the lemongrass plant, when reacted with aqueous chloroaurate ions, yields a high percentage of thin, flat, single-crystalline gold nanotriangles. The nanotriangles seem to grow by a process involving rapid reduction, assembly and room-temperature sintering of 'liquid-like' spherical gold nanoparticles. The anisotropy in nanoparticle shape results in large near-infrared absorption by the particles, and highly anisotropic electron transport in films of the nanotriangles.

  16. Histological assessment of the triangular fibrocartilage complex.

    Science.gov (United States)

    Semisch, M; Hagert, E; Garcia-Elias, M; Lluch, A; Rein, S

    2016-06-01

    The morphological structure of the seven components of triangular fibrocartilage complexes of 11 cadaver wrists of elderly people was assessed microscopically, after staining with Hematoxylin-Eosin and Elastica van Gieson. The articular disc consisted of tight interlaced fibrocartilage without blood vessels except in its ulnar part. Volar and dorsal radioulnar ligaments showed densely parallel collagen bundles. The subsheath of the extensor carpi ulnaris muscle, the ulnotriquetral and ulnolunate ligament showed mainly mixed tight and loose parallel tissue. The ulnolunate ligament contained tighter parallel collagen bundles and clearly less elastic fibres than the ulnotriquetral ligament. The ulnocarpal meniscoid had an irregular morphological composition and loose connective tissue predominated. The structure of the articular disc indicates a buffering function. The tight structure of radioulnar and ulnolunate ligaments reflects a central stabilizing role, whereas the ulnotriquetral ligament and ulnocarpal meniscoid have less stabilizing functions. © The Author(s) 2015.

  17. Filling Transitions in Acute and Open Wedges.

    Czech Academy of Sciences Publication Activity Database

    Malijevský, Alexandr; Parry, A.O.

    2015-01-01

    Roč. 91, č. 5 (2015), s. 052401 ISSN 1539-3755 R&D Projects: GA ČR GA13-09914S Grant - others:EPSRC(GB) EP/J009636/1; EPSRC(GB) EP/I019111/1 Institutional support: RVO:67985858 Keywords : wetting transitions * wedges * density functional theory Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.288, year: 2014

  18. Comments related to infinite wedge representations

    OpenAIRE

    Grieve, Nathan

    2016-01-01

    We study the infinite wedge representation and show how it is related to the universal extension of $g[t,t^{-1}]$ the loop algebra of a complex semi-simple Lie algebra $g$. We also give an elementary proof of the boson-fermion correspondence. Our approach to proving this result is based on a combinatorial construction with partitions combined with an application of the Murnaghan-Nakayama rule.

  19. Elastic wave diffraction by infinite wedges

    Energy Technology Data Exchange (ETDEWEB)

    Fradkin, Larissa; Zernov, Victor [Sound Mathematics Ltd., Cambridge CB4 2AS (United Kingdom); Gautesen, Arthur [Mathematics Department, Iowa State University and Ames Laboratory (United States); Darmon, Michel, E-mail: l.fradkin@soundmathematics.com [CEA-LIST, CEA-Saclay, 91191 Gif-sur-Yvette (France)

    2011-01-01

    We compare two recently developed semi-analytical approaches to the classical problem of diffraction by an elastic two dimensional wedge, one based on the reciprocity principle and Fourier Transform and another, on the representations of the elastodynamic potentials in the form of Sommerfeld Integrals. At present, in their common region of validity, the approaches are complementary, one working better than the other at some isolated angles of incidence.

  20. Localization of observables in the Rindler wedge

    Science.gov (United States)

    Asorey, M.; Balachandran, A. P.; Marmo, G.; de Queiroz, A. R.

    2017-11-01

    One of the striking features of QED is that charged particles create a coherent cloud of photons. The resultant coherent state vectors of photons generate a nontrivial representation of the localized algebra of observables that do not support a representation of the Lorentz group: Lorentz symmetry is spontaneously broken. We show in particular that Lorentz boost generators diverge in this representation, a result shown also by Balachandran et al. [Eur. Phys. J. C 75, 89 (2015), 10.1140/epjc/s10052-015-3305-0] (see also the work by Balachandran et al. [Mod. Phys. Lett. A 28, 1350028 (2013), 10.1142/S0217732313500284]. Localization of observables, for example in the Rindler wedge, uses Poincaré invariance in an essential way [Int. J. Geom. Methods Mod. Phys. 14, 1740008 (2017)., 10.1142/S0219887817400084]. Hence, in the presence of charged fields, the photon observables cannot be localized in the Rindler wedge. These observations may have a bearing on the black hole information loss paradox, as the physics in the exterior of the black hole has points of resemblance to that in the Rindler wedge.

  1. Triangularity effects on the collisional diffusion for elliptic tokamak plasma

    International Nuclear Information System (INIS)

    Martin, P.; Castro, E.

    2007-01-01

    In this conference the effect of ellipticity and triangularity will be analyzed for axisymmetric tokamak in the collisional regime. Analytic forms for the magnetic field cross sections are taken from those derived recently by other authors [1,2]. Analytical results can be obtained in elliptic plasmas with triangularity by using an special system of tokamak coordinates recently published [3-5]. Our results show that triangularities smaller than 0.6, increases confinement for ellipticities in the range 1.2 to 2. This behavior happens for negative and positive triangularities; however this effect is stronger for positive than for negative triangularities. The maximum diffusion velocity is not obtained for zero triangularity, but for small negative triangularities. Ellipticity is also very important in confinement, but the effect of triangularity seems to be more important. High electric inductive field increases confinement, though this field is difficult to modify once the tokamak has been built. The analytic form of the current produced by this field is like that of a weak Ware pinch with an additional factor, which weakens the effect by an order of magnitude. The dependence of the triangularity effect with the Shafranov shift is also analyzed. References 1. - L. L. Lao, S. P. Hirshman, and R. M. Wieland, Phys. Fluids 24, 1431 (1981) 2. - G. O. Ludwig, Plasma Physics Controlled Fusion 37, 633 (1995) 3. - P. Martin, Phys. Plasmas 7, 2915 (2000) 4. - P. Martin, M. G. Haines and E. Castro, Phys. Plasmas 12, 082506 (2005) 5. - P. Martin, E. Castro and M. G. Haines, Phys. Plasmas 12, 102505 (2005)

  2. Observation of the dispersion of wedge waves propagating along cylinder wedge with different truncations by laser ultrasound technique

    Science.gov (United States)

    Jia, Jing; Zhang, Yu; Han, Qingbang; Jing, Xueping

    2017-10-01

    The research focuses on study the influence of truncations on the dispersion of wedge waves propagating along cylinder wedge with different truncations by using the laser ultrasound technique. The wedge waveguide models with different truncations were built by using finite element method (FEM). The dispersion curves were obtained by using 2D Fourier transformation method. Multiple mode wedge waves were observed, which was well agreed with the results estimated from Lagasse's empirical formula. We established cylinder wedge with radius of 3mm, 20° and 60°angle, with 0μm, 5μm, 10μm, 20μm, 30μm, 40μm, and 50μm truncations, respectively. It was found that non-ideal wedge tip caused abnormal dispersion of the mode of cylinder wedge, the modes of 20° cylinder wedge presents the characteristics of guide waves which propagating along hollow cylinder as the truncation increasing. Meanwhile, the modes of 60° cylinder wedge with truncations appears the characteristics of guide waves propagating along hollow cylinder, and its mode are observed clearly. The study can be used to evaluate and detect wedge structure.

  3. A New Triangular Flat Shell Element With Drilling Rotations

    DEFF Research Database (Denmark)

    Damkilde, Lars

    2008-01-01

    A new flat triangular shell element has been developed based on a newly developed triangular plate bending element by the author and a new triangular membrane element with drilling degrees of freedom. The advantage of the drilling degree of freedom is that no special precautions have to be made...... in connecting with assembly of elements. Due to the drilling rotations all nodal degrees of freedom have stiffness, and therefore no artificial suppression of degrees of freedom are needed for flat or almost flat parts of the shell structure....

  4. On Certain Topological Indices of Boron Triangular Nanotubes

    Science.gov (United States)

    Aslam, Adnan; Ahmad, Safyan; Gao, Wei

    2017-08-01

    The topological index gives information about the whole structure of a chemical graph, especially degree-based topological indices that are very useful. Boron triangular nanotubes are now replacing usual carbon nanotubes due to their excellent properties. We have computed general Randić (Rα), first Zagreb (M1) and second Zagreb (M2), atom-bond connectivity (ABC), and geometric-arithmetic (GA) indices of boron triangular nanotubes. Also, we have computed the fourth version of atom-bond connectivity (ABC4) and the fifth version of geometric-arithmetic (GA5) indices of boron triangular nanotubes.

  5. On certain topological indices of boron triangular nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Aslam, Adnan [Univ. of Engineering and Technology, Lahore (Pakistan). Dept. of Natural Sciences and Humanities; Ahmad, Safyan [GC Univ. Lahore (Pakistan). Abdus Salam School of Mathematical Sciences; Gao, Wei [Yunnan Normal Univ., Kunming (China). School of Information Science and Technology

    2017-11-01

    The topological index gives information about the whole structure of a chemical graph, especially degree-based topological indices that are very useful. Boron triangular nanotubes are now replacing usual carbon nanotubes due to their excellent properties. We have computed general Randic (R{sub a}), first Zagreb (M{sub 1}) and second Zagreb (M{sub 2}), atom-bond connectivity (ABC), and geometric-arithmetic (GA) indices of boron triangular nanotubes. Also, we have computed the fourth version of atom-bond connectivity (ABC{sub 4}) and the fifth version of geometric-arithmetic (GA{sub 5}) indices of boron triangular nanotubes.

  6. Forces in Motzkin paths in a wedge

    International Nuclear Information System (INIS)

    Janse van Rensburg, E J

    2006-01-01

    Entropic forces in models of Motzkin paths in a wedge geometry are considered as models of forces in polymers in confined geometries. A Motzkin path in the square lattice is a path from the origin to a point in the line Y = X while it never visits sites below this line, and it is constrained to give unit length steps only in the north and east directions and steps of length √2 in the north-east direction. Motzkin path models may be generalized to ensembles of NE-oriented paths above the line Y = rX, where r > 0 is an irrational number. These are paths giving east, north and north-east steps from the origin in the square lattice, and confined to the r-wedge formed by the Y-axis and the line Y = rX. The generating function g r of these paths is not known, but if r > 1, then I determine its radius of convergence to be t r = min (r-1)/r≤y≤r/(r+1) [y y (1-r(1-y)) 1-r(1-y) (r(1-y)-y) r(1-y)-y ] and if r is an element of (0, 1), then t r = 1/3. The entropic force the path exerts on the line Y rX may be computed from this. An asymptotic expression for the force for large values of r is given by F(r) = log(2r)/r 2 - (1+2log(2r))/2r 3 + O (log(2r)/r 4 ). In terms of the vertex angle α of the r-wedge, the moment of the force about the origin has leading terms F(α) log(2/α) - (α/2)(1+2log(2/α)) + O(α 2 log(2/α)) as α → 0 + and F(α) = 0 if α is element of [π/4, π/2]. Moreover, numerical integration of the force shows that the total work done by closing the wedge is 1.085 07... lattice units. An alternative ensemble of NE-oriented paths may be defined by slightly changing the generating function g r . In this model, it is possible to determine closed-form expressions for the limiting free energy and the force. The leading term in an asymptotic expansions for this force agrees with the leading term in the asymptotic expansion of the above model, and the subleading term only differs by a factor of 2

  7. Triangular model integrating clinical teaching and assessment

    Directory of Open Access Journals (Sweden)

    Abdelaziz A

    2014-03-01

    Full Text Available Adel Abdelaziz,1,2 Emad Koshak3 1Medical Education Development Unit, Faculty of Medicine, Al Baha University, Al Baha, Saudi Arabia; 2Medical Education Department, Faculty of Medicine, Suez Canal University, Egypt; 3Dean and Internal Medicine Department, Faculty of Medicine, Al Baha University, Al Baha, Saudi Arabia Abstract: Structuring clinical teaching is a challenge facing medical education curriculum designers. A variety of instructional methods on different domains of learning are indicated to accommodate different learning styles. Conventional methods of clinical teaching, like training in ambulatory care settings, are prone to the factor of coincidence in having varieties of patient presentations. Accordingly, alternative methods of instruction are indicated to compensate for the deficiencies of these conventional methods. This paper presents an initiative that can be used to design a checklist as a blueprint to guide appropriate selection and implementation of teaching/learning and assessment methods in each of the educational courses and modules based on educational objectives. Three categories of instructional methods were identified, and within each a variety of methods were included. These categories are classroom-type settings, health services-based settings, and community service-based settings. Such categories have framed our triangular model of clinical teaching and assessment. Keywords: curriculum development, teaching, learning, assessment, apprenticeship, community-based settings, health service-based settings

  8. Quadratic polynomial interpolation on triangular domain

    Science.gov (United States)

    Li, Ying; Zhang, Congcong; Yu, Qian

    2018-04-01

    In the simulation of natural terrain, the continuity of sample points are not in consonance with each other always, traditional interpolation methods often can't faithfully reflect the shape information which lie in data points. So, a new method for constructing the polynomial interpolation surface on triangular domain is proposed. Firstly, projected the spatial scattered data points onto a plane and then triangulated them; Secondly, A C1 continuous piecewise quadric polynomial patch was constructed on each vertex, all patches were required to be closed to the line-interpolation one as far as possible. Lastly, the unknown quantities were gotten by minimizing the object functions, and the boundary points were treated specially. The result surfaces preserve as many properties of data points as possible under conditions of satisfying certain accuracy and continuity requirements, not too convex meantime. New method is simple to compute and has a good local property, applicable to shape fitting of mines and exploratory wells and so on. The result of new surface is given in experiments.

  9. Electro-osmotic flows inside triangular microchannels

    International Nuclear Information System (INIS)

    Vocale, P; Spiga, M; Geri, M; Morini, G L

    2014-01-01

    This work presents a numerical investigation of both pure electro-osmotic and combined electro-osmotic/pressure-driven flows inside triangular microchannels. A finite element analysis has been adopted to solve the governing equations for the electric potential and the velocity field, accounting for a finite thickness of the electric double layer. The influence of non-dimensional parameters such as the aspect ratio of the cross-section, the electrokinetic diameter and the ratio of the pressure force to the electric force on the flow behavior has been investigated. Numerical results point out that the velocity field is significantly influenced by the aspect ratio of the cross section and the electrokinetic diameter. More specifically, the aspect ratio plays an important role in determining the maximum volumetric flow rate, while the electrokinetic diameter is crucial to establishing the range of pressures that may be sustained by the electro-osmotic flow. Numerical results are also compared with two correlations available in the literature which enable to assess the volumetric flow rate and the pressure head for microchannels featuring a rectangular, a trapezoidal or an elliptical cross-section.

  10. The problem 7 forming triangular geometric line field

    Directory of Open Access Journals (Sweden)

    Travush Vladimir Iljich

    2016-01-01

    Full Text Available Investigated a method of formation of triangular networks in the field. Delivered conditions the problem of locating a triangular network in the area. The criterion for assessing the effectiveness of the solution of the problem is the minimum number of sizes of the dome elements, the possibility of pre-assembly and pre-stressing. The solution of the problem of one embodiment of a triangular network of accommodation in a compatible spherical triangle and, accordingly, on the sphere. Optimization of triangular geometric network on a sphere on the criterion of minimum sizes of elements can be solved by placing the system in an irregular hexagon inscribed in a circle of minimal size, maximum regular hexagons.

  11. The problem 4 of placement triangular geometric line field

    Directory of Open Access Journals (Sweden)

    Travush Vladimir Iljich

    2016-01-01

    Full Text Available One of the a method of formation of triangular networks in the field is investigated. Conditions the problem of locating a triangular network in the area are delivered. The criterion for assessing the effectiveness of the solution of the problem is the minimum number of sizes of the dome elements, the possibility of pre-assembly and pre-stressing. The solution of the problem of one embodiment of a triangular network of accommodation in a compatible spherical triangle and, accordingly, on the sphere. Optimization of triangular geometric network on a sphere on the criterion of minimum sizes of elements can be solved by placing the system in an irregular hexagon inscribed in a circle of minimal size, maximum regular hexagons.

  12. 2-D modeling of dual-mode acoustic phonon excitation of a triangular nanoplate

    Science.gov (United States)

    Tai, Po-Tse; Yu, Pyng; Tang, Jau

    2010-08-01

    In this theoretical work, we investigated coherent phonon excitation of a triangular nanoplate based on 2-D Fermi-Pasta-Ulam lattice model. Based on the two-temperature model commonly used in description of laser heating of metals, we considered two kinds of forces related to electronic and lattice stresses. Based on extensive simulation and analysis, we identified two major planar phonon modes, namely, a standing wave mode related to the triangle bisector and another mode corresponding to half of the side length. This work elucidates the roles of laser-induced electronic stress and lattice stress in controlling the initial phase and the amplitude ratio between these two phonon modes.

  13. Triangular arbitrage as an interaction among foreign exchange rates

    Science.gov (United States)

    Aiba, Yukihiro; Hatano, Naomichi; Takayasu, Hideki; Marumo, Kouhei; Shimizu, Tokiko

    2002-07-01

    We first show that there are in fact triangular arbitrage opportunities in the spot foreign exchange markets, analyzing the time dependence of the yen-dollar rate, the dollar-euro rate and the yen-euro rate. Next, we propose a model of foreign exchange rates with an interaction. The model includes effects of triangular arbitrage transactions as an interaction among three rates. The model explains the actual data of the multiple foreign exchange rates well.

  14. On the Eigenvalues and Eigenvectors of Block Triangular Preconditioned Block Matrices

    KAUST Repository

    Pestana, Jennifer

    2014-01-01

    Block lower triangular matrices and block upper triangular matrices are popular preconditioners for 2×2 block matrices. In this note we show that a block lower triangular preconditioner gives the same spectrum as a block upper triangular preconditioner and that the eigenvectors of the two preconditioned matrices are related. © 2014 Society for Industrial and Applied Mathematics.

  15. Wedge cutting of mild steel by CO 2 laser and cut-quality assessment in relation to normal cutting

    Science.gov (United States)

    Yilbas, B. S.; Karatas, C.; Uslan, I.; Keles, O.; Usta, Y.; Yilbas, Z.; Ahsan, M.

    2008-10-01

    In some applications, laser cutting of wedge surfaces cannot be avoided in sheet metal processing and the quality of the end product defines the applicability of the laser-cutting process in such situations. In the present study, CO 2 laser cutting of the wedge surfaces as well as normal surfaces (normal to laser beam axis) is considered and the end product quality is assessed using the international standards for thermal cutting. The cut surfaces are examined by the optical microscopy and geometric features of the cut edges such as out of flatness and dross height are measured from the micrographs. A neural network is introduced to classify the striation patterns of the cut surfaces. It is found that the dross height and out of flatness are influenced significantly by the laser output power, particularly for wedge-cutting situation. Moreover, the cut quality improves at certain value of the laser power intensity.

  16. Refinement of the wedge bar technique for compression tests at intermediate strain rates

    Directory of Open Access Journals (Sweden)

    Stander M.

    2012-08-01

    Full Text Available A refined development of the wedge-bar technique [1] for compression tests at intermediate strain rates is presented. The concept uses a wedge mechanism to compress small cylindrical specimens at strain rates in the order of 10s−1 to strains of up to 0.3. Co-linear elastic impact principles are used to accelerate the actuation mechanism from rest to test speed in under 300μs while maintaining near uniform strain rates for up to 30 ms, i.e. the transient phase of the test is less than 1% of the total test duration. In particular, a new load frame, load cell and sliding anvil designs are presented and shown to significantly reduce the noise generated during testing. Typical dynamic test results for a selection of metals and polymers are reported and compared with quasistatic and split Hopkinson pressure bar results.

  17. Statics of loose triangular embankment under Nadai’s sand hill analogy

    Science.gov (United States)

    Pipatpongsa, Thirapong; Heng, Sokbil; Iizuka, Atsushi; Ohta, Hideki

    2010-10-01

    In structural mechanics, Nadai's sand hill analogy is the interpretation of an ultimate torque applied to a given structural member with a magnitude that is analogously twice the volume of stable sand heap which can be accommodated on a transverse cross-section basis. Nadai's analogy is accompanied by his observation of a loose triangular embankment, based on the fact that gravitating loose earth is stable if inclined just under the angle of repose. However, Nadai's analysis of stress distribution in a planar sand heap was found to be inaccurate because the total pressure obtained from Nadai's solution is greater than the self-weight calculated from the heap geometry. This raises a question about the validity of his observation in relation to the analogy. To confirm his criterion, this article presents and corrects the error found in Nadai's solution by analyzing a radially symmetric stress field for a wedge-shaped sand heap with the purpose of satisfying both force balance and Nadai's closure. The fundamental equation was obtained by letting the friction state vary as a function of angular position and deduce it under the constraint that the principal stress orientation obeys Nadai's closure. The theoretical solution sufficiently agreed with the past experimental measurements.

  18. Wedge silicon detectors for the inner trackering system of CMS

    International Nuclear Information System (INIS)

    Catacchini, E.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Meschini, M.; Parrini, G.; Pieri, M.; Wheadon, R.

    1997-01-01

    One ''wedge'' double sided silicon detector prototype for the CMS forward inner tracker has been tested both in laboratory and on a high energy particle beam. The results obtained indicate the most reliable solutions for the strip geometry of the junction side. Three different designs of ''wedge'' double sided detectors with different solutions for the ohmic side strip geometry are presented. (orig.)

  19. Surface Geophysical Measurements for Locating and Mapping Ice-Wedges

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas; Tomaskovicova, Sonia; Larsen, S.H.

    2012-01-01

    to test the applicability of DC electrical resistivity tomography (ERT) and Ground Penetrating Radar (GPR) to identifying and mapping ice-wedge occurrences. The site is located in Central West Greenland, and the ice-wedges are found in a permafrozen peat soil with an active layer of about 30 cm. ERT...

  20. Beam profiles in the nonwedged direction for dynamic wedges

    International Nuclear Information System (INIS)

    Lydon, J.M.; Rykers, K.L.

    1996-01-01

    One feature of the dynamic wedge is the improved flatness of the beam profile in the nonwedged direction when compared to fixed wedges. Profiles in the nonwedged direction for fixed wedges show a fall-off in dose away from the central axis when compared to the open field profile. This study will show that there is no significant difference between open field profiles and nonwedged direction profiles for dynamically wedged beams. The implications are that the dynamic wedge offers an improved dose distribution in the nonwedged direction that can be modelled by approximating the dynamically wedged field to an open field. This is possible as both the profiles and depth doses of the dynamically wedged fields match those of the open fields, if normalized to d max of the same field size. For treatment planning purposes the effective wedge factor (EWF) provides a normalization factor for the open field depth dose data set. Data will be presented to demonstrate that the EWF shows relatively little variation with depth and can be treated as being independent of field size in the nonwedged direction. (author)

  1. locally fabricated metal step wedge for quality assurance

    African Journals Online (AJOL)

    DR. AMINU

    naturally/artificially occurring radioactive elements, ... energy to improve health care, as in radiography, ... The use of low performance x-ray machines. b. .... carried out using the digital densitometer x-rite 3 31 nickel-cadmium. (NiCad) battery.

  2. Locally fabricated metal step wedge for quality assurance in ...

    African Journals Online (AJOL)

    The code of safe practice for the use of x-rays in medical diagnosis requires that each x-ray facility has an appropriate quality assurance program in radiation protection, to ensure accurate diagnosis, and to keep doses as low as reasonably achievable. This requires an in-house system of regular checks and procedures.

  3. Tax wedge in Croatia, Austria, Hungary, Poland and Greece

    Directory of Open Access Journals (Sweden)

    Marin Onorato

    2016-06-01

    Full Text Available The aim of this paper is to compare the tax burden on labour income in Croatia, Austria, Greece, Hungary and Poland in 2013. The Taxing Wages methodology has been applied to hypothetical units across a range of gross wages in order to calculate net average tax wedge, net average tax rate, as well as other relevant indicators. When it comes to single workers without children, the smallest tax wedge for workers earning less than the average gross wage was found in Croatia, while Poland had the smallest tax wedge for above-average wages. Due to a progressive PIT system, the tax wedge for a single worker in Croatia reaches 50% at 400% of the average gross wage, equalling that of Austria, Greece and Hungary. Tax wedges for couples with two children show a similar trend.

  4. Dosimetry verifications of the physical parameters of virtual wedge on a Siemens accelerator

    International Nuclear Information System (INIS)

    Zhong Heli; Li Xiaodong; Li Longxing

    2002-01-01

    Objective: To verify the wedge angle of virtual wedge and the relation between wedge factor and beam energy, field size, wedge angle and to study the difference in percent depth dose (PDD) of virtual wedge field, hard wedge field and open field. Methods: Using wedge angle and wedge factor of 15 degree, 30 degree, 45 degree and 60 degree virtual wedge of Siemens Mevatron 6 MV and Primus 8 MV, 18 MV X rays were measured by RFA-plus 3D water phantom and RK finger chamber the PDD of the virtual wedge field, hard wedge field and open field were measured by Kodak XV-2 verifying film and FDM-300 film dosimeter. These PDDs were normalized to Dmax then compared. Results: There was good conformation between virtual wedge measured by four point method and set value. The virtual wedge was almost equal to 1, with a maximal variation of 0.031 no matter what the value of beam energy, field size or wedge angle was. Generally, for certain energy and field size, the wedge factor of larger wedge angle was slightly larger than smaller wedge angle. For certain energy and wedge angle, the wedge factor of larger field was also a little larger than smaller field. The PDD of virtual wedge field was similar to that of open field. Conclusions: The four point method measurement for virtual wedge angle is good for daily QA. Radiotherapy of virtual wedge field is not only simpler than hard wedge field, but also spares the beam output. The PDD conferment between virtual field and open field simplifies radiation treatment planning and increases the accuracy of wedge field therapy

  5. Analysis of surface and build up region dose for motorized wedge and omni wedge

    International Nuclear Information System (INIS)

    Panta, Raj Kumar; Sundarum, T.

    2008-01-01

    Megavoltage x-ray beam exhibits the well known phenomenon of dose build-up within the first few millimeters of incident phantom surface or skin. The skin sparing effect of high energy gamma or x-ray photon may be reduced or even lost, if the beam is contaminated with electron or low energy photons. Since skin dose in the treatment of deeply seated tumor may be a limiting factor in the delivery of tumoricidal dose due to possible complications such as erythema, desquamation, fibrosis, necrosis and epilation, the dose distribution in the build up region should be known. The objective of this study was to measure and investigate the surface and build-up region dose for 6 MV and 15 MV photon beam for Motorized wedge and Omni wedge in Precise Digital Linear Accelerator (Elekta)

  6. Effects of Lateral Heel Wedges and Lateral Forefoot Wedge on the Knee Adduction Moment in Healthy Male Students

    Directory of Open Access Journals (Sweden)

    Fatemeh Shamsi

    2012-01-01

    Full Text Available Objective: Lateral wedged insoles have been designed to decrease the force applied on the medial knee compartment. The aim of this study was to assess the effects of laterally wedged insoles regarding to the placement of the wedge under the sole (under the heel or under the forefoot on the knee adduction moment and the ground reaction forces. Material & Methods: In this pretest-posttest study, three-dimensional gait analysis was performed on 20 healthy men between 18-30 years old. Knee adduction moment and ground reaction forces were compared among following three types of insoles: a flat insole, a 6˚ laterally inclined heel wedged insole and a 6˚ laterally- inclined forefoot wedged insole. Results: there was no difference between three conditions (flat insole (9.72±1.501, lateral heel wedge (9.866±2.141 and lateral forefoot wedge (9.952±1.986 in peak knee adduction moment (P>0.05. Ground reaction forces and spatiotemporal parameters of gait were not affected by any types of these insoles (P>0.05. Conclusion: Based on the current finding, placement of the lateral wedge under the sole, that is, under the heel or under the forefoot has no effect on the efficacy of these insoles on the adduction moment of the knee and ground reaction forces.

  7. Manual cross check of computed dose times for motorised wedged fields

    International Nuclear Information System (INIS)

    Porte, J.

    2001-01-01

    If a mass of tissue equivalent material is exposed in turn to wedged and open radiation fields of the same size, for equal times, it is incorrect to assume that the resultant isodose pattern will be effectively that of a wedge having half the angle of the wedged field. Computer programs have been written to address the problem of creating an intermediate wedge field, commonly known as a motorized wedge. The total exposure time is apportioned between the open and wedged fields, to produce a beam modification equivalent to that of a wedged field of a given wedge angle. (author)

  8. Design assessment of triangular support bracket for manufacturability

    International Nuclear Information System (INIS)

    Kim, Yu-Gyeong; Jung, Yung-Jin; Kim, Hyun-Soo; Ahn, Hee-Jae

    2015-01-01

    Highlights: • Various designs for ITER triangular support bracket are proposed in terms of efficient manufacturability. • An optimized design for structural safety is determined in accordance with RCC-MR. • This result is reconfirmed by cross-checking in comparison with the IO baseline of integrity. - Abstract: The triangular support is connected structurally and hydraulically with the inner shell of the vacuum vessel and its main role is to keep plasma vertical stability during operational disruptions. Korea is responsible for the procurement of sectors 1 and 6 of the main vessel including triangular support. At present, design review for its fabrication by ITER Korea and Hyundai Heavy Industries, Co., Ltd. is in progress. This paper presents the results on various designs for triangular support bracket in terms of manufacturability considering both easiness of non-destructive evaluation and fabrication efficiency. The several designs are proposed and evaluated under the most critical loading condition using elastic and limit analysis with fatigue evaluation. Consequently, an optimized design for structural safety is determined in accordance with RCC-MR. This result is reconfirmed by cross-checking in comparison with the baseline of integrity that already had been determined by ITER Organization. The design deviation requests of triangular support bracket have been submitted to ITER Organization and Agreed Notified Body for approval, and their verification is currently under discussion.

  9. The Tax Wedge in Slovenia: International Comparison and Policy Recommendations

    Directory of Open Access Journals (Sweden)

    Primož Dolenc

    2005-09-01

    Full Text Available When taxes on labor are introduced, a “tax wedge” appears between the labor costs paid by the employer (gross wage and the net wage received by an employee. At a certain level of wage, a higher tax wedge increases unemployment and decreases employment, all other things being equal. The paper tackles three main questions: the characteristics of the tax wedge, unemployment and employment rates in OECD countries in the recent past, tax wedge policy in the EU15 and the new EU members and the tax system and its effects on the unemployment and employment rates in Slovenia. We found that the OECD countries can be classified into two groups of countries if the tax wedge, the unemployment rate and the employment rate are taken into consideration. The first group is the high tax wedge, high unemployment rate and low employment rate group of countries, whereas the other group has the opposite characteristics. European member states (old and new have on average a higher tax burden on labor than the OECD average, consequently suffering from higher unemployment rates. Slovenia has an unreasonably high tax wedge; in the EU only Belgium and Germany have a higher tax burden. According to previous and our empirical findings we suggest that Slovenia could benefit from a reduction in the tax wedge.

  10. Synthesis of triangular Au core-Ag shell nanoparticles

    International Nuclear Information System (INIS)

    Rai, Akhilesh; Chaudhary, Minakshi; Ahmad, Absar; Bhargava, Suresh; Sastry, Murali

    2007-01-01

    In this paper, we demonstrate a simple and reproducible method for the synthesis of triangular Au core-Ag shell nanoparticles. The triangular gold core is obtained by the reduction of gold ions by lemongrass extract. Utilizing the negative charge on the gold nanotriangles, silver ions are bound to their surface and thereafter reduced by ascorbic acid under alkaline conditions. The thickness of the silver shell may be modulated by varying the pH of the reaction medium. The formation of the Au core-Ag shell triangular nanostructures has been followed by UV-vis-NIR Spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy (TEM) and atomic force microscopy (AFM) measurements. The sharp vertices of the triangles coupled with the core-shell structure is expected to have potential for application in surface enhanced Raman spectroscopy and in the sensitive detection of biomolecules

  11. Optimization of triangular microchannel heat sinks using constructible theory

    International Nuclear Information System (INIS)

    Mardani, Moloud; Salimpour, Mohammad Reza

    2016-01-01

    The present paper examines the optimization of triangular microchannel heat sinks. The impact of volume fraction of solid material and pressure drop on the maximum temperature of the microchannel heat sinks are investigated and their optimum operating conditions are compared. From the results, it is seen that increasing the side angle of the triangular microchannel, improves its performance. Furthermore, there is an appropriate agreement between the analytical and numerical results. Finally, the effect of degrees of freedom on the performance of microchannels is investigated. To accomplish this end, the triangular microchannels with the side angle of 60 degree have been chosen as it has the best performance compared to other microchannels. It is observed that the minimized maximum temperatures of optimized microchannel heat sinks with three degrees of freedom are 10% lower than the ones with two degrees of freedom

  12. Group sequential designs for stepped-wedge cluster randomised trials.

    Science.gov (United States)

    Grayling, Michael J; Wason, James Ms; Mander, Adrian P

    2017-10-01

    The stepped-wedge cluster randomised trial design has received substantial attention in recent years. Although various extensions to the original design have been proposed, no guidance is available on the design of stepped-wedge cluster randomised trials with interim analyses. In an individually randomised trial setting, group sequential methods can provide notable efficiency gains and ethical benefits. We address this by discussing how established group sequential methodology can be adapted for stepped-wedge designs. Utilising the error spending approach to group sequential trial design, we detail the assumptions required for the determination of stepped-wedge cluster randomised trials with interim analyses. We consider early stopping for efficacy, futility, or efficacy and futility. We describe first how this can be done for any specified linear mixed model for data analysis. We then focus on one particular commonly utilised model and, using a recently completed stepped-wedge cluster randomised trial, compare the performance of several designs with interim analyses to the classical stepped-wedge design. Finally, the performance of a quantile substitution procedure for dealing with the case of unknown variance is explored. We demonstrate that the incorporation of early stopping in stepped-wedge cluster randomised trial designs could reduce the expected sample size under the null and alternative hypotheses by up to 31% and 22%, respectively, with no cost to the trial's type-I and type-II error rates. The use of restricted error maximum likelihood estimation was found to be more important than quantile substitution for controlling the type-I error rate. The addition of interim analyses into stepped-wedge cluster randomised trials could help guard against time-consuming trials conducted on poor performing treatments and also help expedite the implementation of efficacious treatments. In future, trialists should consider incorporating early stopping of some kind into

  13. Employment and productivity: The role of the tax wedge

    Directory of Open Access Journals (Sweden)

    Andrea FESTA

    2015-11-01

    Full Text Available After the economic crisis, many countries aim at reducing unemployment and foster productivity. To address these issues one of the most common policy indications recommends lowering the tax wedge on labour in order to increase employment and growth. As a consequence, a review of the empirical studies focused on the relation between tax wedge, employment and productivity is an useful and demanding exercise, especially in those European countries where the topic is on the front page of the domestic policy debate because the productivity growth is low and the tax wedge on labour is high.

  14. Optical wedge method for spatial reconstruction of particle trajectories

    International Nuclear Information System (INIS)

    Asatiani, T.L.; Alchudzhyan, S.V.; Gazaryan, K.A.; Zograbyan, D.Sh.; Kozliner, L.I.; Krishchyan, V.M.; Martirosyan, G.S.; Ter-Antonyan, S.V.

    1978-01-01

    A technique of optical wedges allowing the full reconstruction of pictures of events in space is considered. The technique is used for the detection of particle tracks in optical wide-gap spark chambers by photographing in one projection. The optical wedges are refracting right-angle plastic prisms positioned between the camera and the spark chamber so that through them both ends of the track are photographed. A method for calibrating measurements is given, and an estimate made of the accuracy of the determination of the second projection with the help of the optical wedges

  15. Arthrography in lesions of triangular fibrocartilage of the wrist

    International Nuclear Information System (INIS)

    Rau, W.S.; Seifert, J.

    1982-01-01

    Arthography of the wrist is a safe method to demonstrate lesions of the triangular fibrocartilage. Indications are posttraumatic pain and restriction of movement of the wrist. Lesions of the triangular fibrocartilage are caused by a distal fracture of the radius with shortening, sudden drop on the overextended hand and work with rock drills. The extent of injury is quite different: small fissures and splits, detachment of the discus from the lower end of the ulna, fragmentation and destruction of the fibrocartilage. Problems of therapy, however, are greater than problems of diagnosis: actually there is no generally adopted surgical method for the treatment of discus lections. (orig./MG)

  16. The centre of mass of a triangular plate

    International Nuclear Information System (INIS)

    Sluesarenko, Viktor; Rojas, Roberto; Fuster, Gonzalo

    2008-01-01

    We present a derivation for the coordinates of the centre of mass-or centre of gravity-of a homogeneous triangular plate by using scaling and symmetry. We scale the triangular plate by a factor of 2 and divide its area into four plates identical to the original. By symmetry, we assert that the centre of mass of two identical masses lies at the midpoint of the line joining their centres of mass. By relating the centres of mass of the original to those of the scaled plates, we find the coordinates of the centre of mass as the solution of an algebraic equation

  17. Arthrography in lesions of triangular fibrocartilage of the wrist

    Energy Technology Data Exchange (ETDEWEB)

    Rau, W.S.; Seifert, J.

    1982-05-01

    Arthography of the wrist is a safe method to demonstrate lesions of the triangular fibrocartilage. Indications are posttraumatic pain and restriction of movement of the wrist. Lesions of the triangular fibrocartilage are caused by a distal fracture of the radius with shortening, sudden drop on the overextended hand and work with rock drills. The extent of injury is quite different: small fissures and splits, detachment of the discus from the lower end of the ulna, fragmentation and destruction of the fibrocartilage. Problems of therapy, however, are greater than problems of diagnosis: actually there is no generally adopted surgical method for the treatment of discus lesions.

  18. MR imaging of the traumatic triangular fibrocartilaginous complex tear

    Science.gov (United States)

    Griffith, James F.; Fung, Cindy S. Y.; Lee, Ryan K. L.; Tong, Cina S. L.; Wong, Clara W. Y.; Tse, Wing Lim; Ho, Pak Cheong

    2017-01-01

    Triangular fibrocartilage complex is a major stabilizer of the distal radioulnar joint (DRUJ). However, triangular fibrocartilage complex (TFCC) tear is difficult to be diagnosed on MRI for its intrinsic small and thin structure with complex anatomy. The purpose of this article is to review the anatomy of TFCC, state of art MRI imaging technique, normal appearance and features of tear on MRI according to the Palmar’s classification. Atypical tear and limitations of MRI in diagnosis of TFCC tear are also discussed. PMID:28932701

  19. Physichal parameters for wedge filters used in radiotherapy

    International Nuclear Information System (INIS)

    Strunga, Emil

    1995-01-01

    Wedge filters using in radiotherapy up two important problems: attenuation of gamma rays introduced by the presence of wedge filters and spinning of isodoses curves plate. Depending of irradiation geometry, characterised by D w , - source filter distance, D c - source dose's estimate point distance, a - side of irradiation field; nature and size filter: α - wedge angle, μ - linear adsorption coefficient, ε - filter cover attenuation w - filter side, and nature of target volume characterised by μ' - linear absorption coefficient of medium has been estimated absorption factor of wedge filter (k w ) for two irradiation geometry: and spinning angle of isodose plate (Θ): 3) tg θ (μD w (μ'D c - 2 Calculated values has been compared with the experimental measured values, for a cobaltotherapy unit Rokus-M, and the result was that between the two series of dates it is a good concordance

  20. Numerical Study on Critical Wedge Angle of Cellular Detonation Reflections

    International Nuclear Information System (INIS)

    Gang, Wang; Kai-Xin, Liu; De-Liang, Zhang

    2010-01-01

    The critical wedge angle (CWA) for the transition from regular reflection (RR) to Mach reflection (MR) of a cellular detonation wave is studied numerically by an improved space-time conservation element and solution element method together with a two-step chemical reaction model. The accuracy of that numerical way is verified by simulating cellular detonation reflections at a 19.3° wedge. The planar and cellular detonation reflections over 45°–55° wedges are also simulated. When the cellular detonation wave is over a 50° wedge, numerical results show a new phenomenon that RR and MR occur alternately. The transition process between RR and MR is investigated with the local pressure contours. Numerical analysis shows that the cellular structure is the essential reason for the new phenomenon and the CWA of detonation reflection is not a certain angle but an angle range. (fundamental areas of phenomenology(including applications))

  1. Pilot Study: Foam Wedge Chin Support Static Tolerance Testing

    Science.gov (United States)

    2017-10-24

    AFRL-SA-WP-SR-2017-0026 Pilot Study: Foam Wedge Chin Support Static Tolerance Testing Austin M. Fischer, BS1; William W...COVERED (From – To) April – October 2017 4. TITLE AND SUBTITLE Pilot Study: Foam Wedge Chin Support Static Tolerance Testing 5a. CONTRACT NUMBER...PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) USAF School of Aerospace

  2. Scattering of wedges and cones with impedance boundary conditions

    CERN Document Server

    Lyalinov, Mikhail

    2012-01-01

    This book is a systematic and detailed exposition of different analytical techniques used in studying two of the canonical problems, the wave scattering by wedges or cones with impedance boundary conditions. It is the first reference on novel, highly efficient analytical-numerical approaches for wave diffraction by impedance wedges or cones. The applicability of the reported solution procedures and formulae to existing software packages designed for real-world high-frequency problems encountered in antenna, wave propagation, and radar cross section.

  3. On the perturbations of spectra of upper triangular operator matrices

    International Nuclear Information System (INIS)

    Barraa, Mohamed; Boumazgour, Mohamed

    2003-07-01

    In this paper we investigate perturbations of the left essential spectrum, right essential spectrum, essential spectrum and the regular spectrum of an upper triangular operator matrix such as M C - [A 11 C 12 O 21 B 22 ] acting on a Hilbert space H + K. (author)

  4. Anisotropic Adhesion Properties of Triangular-Tip-Shaped Micropillars

    KAUST Repository

    Kwak, Moon Kyu

    2011-06-01

    Directional dry adhesive microstructures consisting of high-density triangular-tip-shaped micropillars are described. The wide-tip structures allow for unique directional shear adhesion properties with respect to the peeling direction, along with relatively high normal adhesion. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Euler y la Conjetura de Fermat sobre Números Triangulares

    Directory of Open Access Journals (Sweden)

    José Manuel Sánchez Muñoz

    2011-04-01

    Full Text Available Este artículo describe la historia de como Euler demostró la existencia de infinitos números triangulares bicuadráticos, desde su correspondencia con su amigo Christian Goldbach hasta la publicación de sus resultados en la Academia de San Petesburgo.

  6. Diffusion on unstructured triangular grids using Lattice Boltzmann

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2004-01-01

    In this paper, we present a Lattice Boltzmann scheme for diffusion on unstructured triangular grids. In this formulation there is no need for interpolation, as is required in other LB schemes on irregular grids. At the end of the propagation step, the lattice gas particles arrive exactly at

  7. Lattice Boltzmann scheme for diffusion on triangular grids

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2003-01-01

    In this paper we present a Lattice Boltzmann scheme for diffusion on it unstructured triangular grids. In this formulation of a LB for irregular grids there is no need for interpolation, which is required in other LB schemes on irregular grids. At the end of the propagation step the lattice gas

  8. Triangular Numbers, Gaussian Integers, and KenKen

    Science.gov (United States)

    Watkins, John J.

    2012-01-01

    Latin squares form the basis for the recreational puzzles sudoku and KenKen. In this article we show how useful several ideas from number theory are in solving a KenKen puzzle. For example, the simple notion of triangular number is surprisingly effective. We also introduce a variation of KenKen that uses the Gaussian integers in order to…

  9. Aranha: a 2D mesh generator for triangular finite elements

    International Nuclear Information System (INIS)

    Fancello, E.A.; Salgado, A.C.; Feijoo, R.A.

    1990-01-01

    A method for generating unstructured meshes for linear and quadratic triangular finite elements is described in this paper. Some topics on the C language data structure used in the development of the program Aranha are also presented. The applicability for adaptive remeshing is shown and finally several examples are included to illustrate the performance of the method in irregular connected planar domains. (author)

  10. Behaviour of Lagrangian triangular mixed fluid finite elements

    Indian Academy of Sciences (India)

    The behaviour of mixed fluid finite elements, formulated based on the Lagrangian frame of reference, is investigated to understand the effects of locking due to incompressibility and irrotational constraints. For this purpose, both linear and quadratic mixed triangular fluid elements are formulated. It is found that there exists a ...

  11. Anisotropic Adhesion Properties of Triangular-Tip-Shaped Micropillars

    KAUST Repository

    Kwak, Moon Kyu; Jeong, Hoon Eui; Bae, Won Gyu; Jung, Ho-Sup; Suh, Kahp Y.

    2011-01-01

    Directional dry adhesive microstructures consisting of high-density triangular-tip-shaped micropillars are described. The wide-tip structures allow for unique directional shear adhesion properties with respect to the peeling direction, along with relatively high normal adhesion. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Dominance on Strict Triangular Norms and Mulholland Inequality

    Czech Academy of Sciences Publication Activity Database

    Petrík, Milan

    2018-01-01

    Roč. 335, 15 March (2018), s. 3-17 ISSN 0165-0114 R&D Projects: GA ČR GJ15-07724Y Institutional support: RVO:67985807 Keywords : dominance relation * Mulholland inequality * strict triangular norm * transitivity Subject RIV: BA - General Mathematics Impact factor: 2.718, year: 2016

  13. Comparison of dosimetric methods for virtual wedge analysis

    International Nuclear Information System (INIS)

    Bailey, M.; Nelson, V.; Collins, O.; West, M.; Holloway, L.; Rajapaske, S.; Arts, J.; Varas, J.; Cho, G.; Hill, R.

    2004-01-01

    Full text: The Siemens Virtual Wedge (Concord, USA) creates wedged beam profile by moving a single collimator jaw across the specified field size whilst varying the dose rate and jaw speed for use in the delivery of radiotherapy treatments. The measurement of the dosimetric characteristics of the Siemens Virtual Wedge poses significant challenges to medical physicists. This study investigates several different methods for measuring and analysing the virtual wedge for data collection for treatment planning systems and ongoing quality assurance. The beam profiles of the Virtual Wedge (VW) were compared using several different dosimetric methods. Open field profiles were measured with Kodak X-Omat V (Rochester, NY, USA) radiographic film and compared with measurements made using the Sun Nuclear Profiler with a Motorized Drive Assembly (MDA) (Melbourne, FL, USA) and the Scanditronix Wellhofer CC13 ionisation chamber and 24 ion Chamber Array (CA24) (Schwarzenbruck, Germany). The resolution of each dosimetric method for open field profiles was determined. The Virtual Wedge profiles were measured with radiographic film the Profiler and the Scanditronix Wellhofer CA 24 ion Chamber Array at 5 different depths. The ease of setup, time taken, analysis and accuracy of measurement were all evaluated to determine the method that would be both appropriate and practical for routine quality assurance of the Virtual Wedge. The open field profiles agreed within ±2% or 2mm for all dosimetric methods. The accuracy of the Profiler and CA24 are limited to half of the step size selected for each of these detectors. For the VW measurements a step size of 2mm was selected for the Profiler and the CA24. The VW profiles for all dosimetric methods agreed within ±2% or 2mm for the main wedged section of the profile. The toe and heel ends of the wedges showed the significant discrepancies dependent upon the dosimetry method used, up to 7% for the toe end with the CA24. The dosimetry of the

  14. Phase diagram and topological phases in the triangular lattice Kitaev-Hubbard model

    Science.gov (United States)

    Li, Kai; Yu, Shun-Li; Gu, Zhao-Long; Li, Jian-Xin

    2016-09-01

    We study the half-filled Hubbard model on a triangular lattice with spin-dependent Kitaev-like hopping. Using the variational cluster approach, we identify five phases: a metallic phase, a non-coplanar chiral magnetic order, a 120° magnetic order, a nonmagnetic insulator (NMI), and an interacting Chern insulator (CI) with a nonzero Chern number. The transition from CI to NMI is characterized by the change of the charge gap from an indirect band gap to a direct Mott gap. Based on the slave-rotor mean-field theory, the NMI phase is further suggested to be a gapless Mott insulator with a spinon Fermi surface or a fractionalized CI with nontrivial spinon topology, depending on the strength of the Kitaev-like hopping. Our work highlights the rising field in which interesting phases emerge from the interplay between band topology and Mott physics.

  15. The evolving energy budget of accretionary wedges

    Science.gov (United States)

    McBeck, Jessica; Cooke, Michele; Maillot, Bertrand; Souloumiac, Pauline

    2017-04-01

    The energy budget of evolving accretionary systems reveals how deformational processes partition energy as faults slip, topography uplifts, and layer-parallel shortening produces distributed off-fault deformation. The energy budget provides a quantitative framework for evaluating the energetic contribution or consumption of diverse deformation mechanisms. We investigate energy partitioning in evolving accretionary prisms by synthesizing data from physical sand accretion experiments and numerical accretion simulations. We incorporate incremental strain fields and cumulative force measurements from two suites of experiments to design numerical simulations that represent accretionary wedges with stronger and weaker detachment faults. One suite of the physical experiments includes a basal glass bead layer and the other does not. Two physical experiments within each suite implement different boundary conditions (stable base versus moving base configuration). Synthesizing observations from the differing base configurations reduces the influence of sidewall friction because the force vector produced by sidewall friction points in opposite directions depending on whether the base is fixed or moving. With the numerical simulations, we calculate the energy budget at two stages of accretion: at the maximum force preceding the development of the first thrust pair, and at the minimum force following the development of the pair. To identify the appropriate combination of material and fault properties to apply in the simulations, we systematically vary the Young's modulus and the fault static and dynamic friction coefficients in numerical accretion simulations, and identify the set of parameters that minimizes the misfit between the normal force measured on the physical backwall and the numerically simulated force. Following this derivation of the appropriate material and fault properties, we calculate the components of the work budget in the numerical simulations and in the

  16. 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)

  17. Casimir effect for a semitransparent wedge and an annular piston

    International Nuclear Information System (INIS)

    Milton, Kimball A.; Wagner, Jef; Kirsten, Klaus

    2009-01-01

    We consider the Casimir energy due to a massless scalar field in a geometry of an infinite wedge closed by a Dirichlet circular cylinder, where the wedge is formed by δ-function potentials, so-called semitransparent boundaries. A finite expression for the Casimir energy corresponding to the arc and the presence of both semitransparent potentials is obtained, from which the torque on the sidewalls can be derived. The most interesting part of the calculation is the nontrivial nature of the angular mode functions. Numerical results are obtained which are closely analogous to those recently found for a magnetodielectric wedge, with the same speed of light on both sides of the wedge boundaries. Alternative methods are developed for annular regions with radial semitransparent potentials, based on reduced Green's functions for the angular dependence, which allows calculations using the multiple-scattering formalism. Numerical results corresponding to the torque on the radial plates are likewise computed, which generalize those for the wedge geometry. Generally useful formulas for calculating Casimir energies in separable geometries are derived.

  18. Block-triangular preconditioners for PDE-constrained optimization

    KAUST Repository

    Rees, Tyrone; Stoll, Martin

    2010-01-01

    In this paper we investigate the possibility of using a block-triangular preconditioner for saddle point problems arising in PDE-constrained optimization. In particular, we focus on a conjugate gradient-type method introduced by Bramble and Pasciak that uses self-adjointness of the preconditioned system in a non-standard inner product. We show when the Chebyshev semi-iteration is used as a preconditioner for the relevant matrix blocks involving the finite element mass matrix that the main drawback of the Bramble-Pasciak method-the appropriate scaling of the preconditioners-is easily overcome. We present an eigenvalue analysis for the block-triangular preconditioners that gives convergence bounds in the non-standard inner product and illustrates their competitiveness on a number of computed examples. Copyright © 2010 John Wiley & Sons, Ltd.

  19. Synthesis of parallel and antiparallel core-shell triangular nanoparticles

    Science.gov (United States)

    Bhattacharjee, Gourab; Satpati, Biswarup

    2018-04-01

    Core-shell triangular nanoparticles were synthesized by seed mediated growth. Using triangular gold (Au) nanoparticle as template, we have grown silver (Ag) shellto get core-shell nanoparticle. Here by changing the chemistry we have grown two types of core-shell structures where core and shell is having same symmetry and also having opposite symmetry. Both core and core-shell nanoparticles were characterized using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) to know the crystal structure and composition of these synthesized core-shell nanoparticles. From diffraction pattern analysis and energy filtered TEM (EFTEM) we have confirmed the crystal facet in core is responsible for such two dimensional growth of core-shell nanostructures.

  20. Block-triangular preconditioners for PDE-constrained optimization

    KAUST Repository

    Rees, Tyrone

    2010-11-26

    In this paper we investigate the possibility of using a block-triangular preconditioner for saddle point problems arising in PDE-constrained optimization. In particular, we focus on a conjugate gradient-type method introduced by Bramble and Pasciak that uses self-adjointness of the preconditioned system in a non-standard inner product. We show when the Chebyshev semi-iteration is used as a preconditioner for the relevant matrix blocks involving the finite element mass matrix that the main drawback of the Bramble-Pasciak method-the appropriate scaling of the preconditioners-is easily overcome. We present an eigenvalue analysis for the block-triangular preconditioners that gives convergence bounds in the non-standard inner product and illustrates their competitiveness on a number of computed examples. Copyright © 2010 John Wiley & Sons, Ltd.

  1. A new method for ordering triangular fuzzy numbers

    Directory of Open Access Journals (Sweden)

    S.H. Nasseri

    2010-09-01

    Full Text Available Ranking fuzzy numbers plays a very important role in linguistic decision making and other fuzzy application systems. In spite of many ranking methods, no one can rank fuzzy numbers with human intuition consistently in all cases. Shortcoming are found in some of the convenient methods for ranking triangular fuzzy numbers such as the coefficient of variation (CV index, distance between fuzzy sets, centroid point and original point, and also weighted mean value. In this paper, we introduce a new method for ranking triangular fuzzy number to overcome the shortcomings of the previous techniques. Finally, we compare our method with some convenient methods for ranking fuzzy numbers to illustrate the advantage our method.

  2. Success Factors of Biotechnology Industry Based on Triangular Fuzzy Number

    OpenAIRE

    Lei, Lei

    2013-01-01

    Based on the theory of competitive advantage and value chain, this paper establishes the indicator system, and develop the strategic framework using the fuzzy Delphi method. Then the triangular fuzzy number model is established using Fuzzy Analytic Hierarchy Process, and the key factors influencing biotechnology industry are extracted. The results show that in terms of weight, the key factors influencing the success of biotechnology industry are sequenced as follows: “open innovation capaci...

  3. Procrustes Problems for General, Triangular, and Symmetric Toeplitz Matrices

    Directory of Open Access Journals (Sweden)

    Juan Yang

    2013-01-01

    Full Text Available The Toeplitz Procrustes problems are the least squares problems for the matrix equation AX=B over some Toeplitz matrix sets. In this paper the necessary and sufficient conditions are obtained about the existence and uniqueness for the solutions of the Toeplitz Procrustes problems when the unknown matrices are constrained to the general, the triangular, and the symmetric Toeplitz matrices, respectively. The algorithms are designed and the numerical examples show that these algorithms are feasible.

  4. A Step-Wise Approach to Elicit Triangular Distributions

    Science.gov (United States)

    Greenberg, Marc W.

    2013-01-01

    Adapt/combine known methods to demonstrate an expert judgment elicitation process that: 1.Models expert's inputs as a triangular distribution, 2.Incorporates techniques to account for expert bias and 3.Is structured in a way to help justify expert's inputs. This paper will show one way of "extracting" expert opinion for estimating purposes. Nevertheless, as with most subjective methods, there are many ways to do this.

  5. Photonic Crystal Waveguides in Triangular Lattice of Nanopillars

    DEFF Research Database (Denmark)

    Chigrin, Dmitry N.; Lavrinenko, Andrei

    2004-01-01

    Photonic nanopillars waveguides have been analysed. Dielectric nanopillars are arranged in such way that they from a tringular lattice of 2D photonic crystal. Dispersion of the modes depends on the direction of the triangular lattice, Ã-J or Ã-X, in which nanopillars arrays are extended. Light fi....... Transmission spectra calculated by FDTD method completely reflect peculiarities of modes dispersion, showing up to 80% transmission for a realistic SOI nanopillar structure....

  6. Local hydrodynamic characteristics of regular triangular lattice of rods

    International Nuclear Information System (INIS)

    Mantlik, F.; Hejna, J.; Cervenka, J.

    1976-06-01

    Results are presented of an experimental investigation of the friction factor, velocity fields and shear stress distribution around a wetted perimeter in a rod bundle of a triangular lattice with a pitch-to-diameter ratio of 1.17. Measurements were made on 19-rod aerodynamical model at the Reynolds number of 42 300 and 211 000. The results indicated a highly significant effect of secondary flow. (author)

  7. Quality assurance technique for absorbed dose distribution in external radiation therapy with non-physical wedges in consideration of the character of the imaging plate

    International Nuclear Information System (INIS)

    Fujibuchi, Toshioh; Fujisaki, Tatsuya; Kurokawa, Masayuki; Sakae, Takeji

    2011-01-01

    The film dose distribution method is used for profile measurements of non-physical wedges, because three-dimensional automatic control water phantoms cannot be used. Recently, many hospitals have adopted computed radiography (CR) systems in preference to automatic developing processors and films. This may allow use of automatic processors to be discontinued. In this study, a beam was irradiated to an Imaging Plate (IP), and then IP was exposed to a fixed amount of light with fading, and we then measured the off-center ratio (OCR) absorbed dose distribution in external radiation therapy with non-physical wedge. This was compared with the OCR measured with an ionization chamber dosimeter. It was consequently possible for IP to approximate the value measured by the ionization chamber dosimeter by using a metal filter. This method offers a simple quality assurance technique for absorbed dose distribution in external radiation therapy with non-physical wedges in consideration of the character of the IP. (author)

  8. Natural convection in asymmetric triangular enclosures heated from below

    Science.gov (United States)

    Kamiyo, O. M.; Angeli, D.; Barozzi, G. S.; Collins, M. W.

    2014-11-01

    Triangular enclosures are typical configurations of attic spaces found in residential as well as industrial pitched-roof buildings. Natural convection in triangular rooftops has received considerable attention over the years, mainly on right-angled and isosceles enclosures. In this paper, a finite volume CFD package is employed to study the laminar air flow and temperature distribution in asymmetric rooftop-shaped triangular enclosures when heated isothermally from the base wall, for aspect ratios (AR) 0.2 <= AR <= 1.0, and Rayleigh number (Ra) values 8 × 105 <= Ra <= 5 × 107. The effects of Rayleigh number and pitch angle on the flow structure and temperature distributions within the enclosure are analysed. Results indicate that, at low pitch angle, the heat transfer between the cold inclined and the hot base walls is very high, resulting in a multi-cellular flow structure. As the pitch angle increases, however, the number of cells reduces, and the total heat transfer rate progressively reduces, even if the Rayleigh number, being based on the enclosure height, rapidly increases. Physical reasons for the above effect are inspected.

  9. Natural convection in asymmetric triangular enclosures heated from below

    International Nuclear Information System (INIS)

    Kamiyo, O M; Angeli, D; Enzo Ferrari, Universita di Modena e Reggio Emilia, via Vignolese 905, I-41125 Modena (Italy))" data-affiliation=" (DIEF – Dipartimento di Ingegneria Enzo Ferrari, Universita di Modena e Reggio Emilia, via Vignolese 905, I-41125 Modena (Italy))" >Barozzi, G S; Collins, M W

    2014-01-01

    Triangular enclosures are typical configurations of attic spaces found in residential as well as industrial pitched-roof buildings. Natural convection in triangular rooftops has received considerable attention over the years, mainly on right-angled and isosceles enclosures. In this paper, a finite volume CFD package is employed to study the laminar air flow and temperature distribution in asymmetric rooftop-shaped triangular enclosures when heated isothermally from the base wall, for aspect ratios (AR) 0.2 ≤ AR ≤ 1.0, and Rayleigh number (Ra) values 8 × 10 5 ≤ Ra ≤ 5 × 10 7 . The effects of Rayleigh number and pitch angle on the flow structure and temperature distributions within the enclosure are analysed. Results indicate that, at low pitch angle, the heat transfer between the cold inclined and the hot base walls is very high, resulting in a multi-cellular flow structure. As the pitch angle increases, however, the number of cells reduces, and the total heat transfer rate progressively reduces, even if the Rayleigh number, being based on the enclosure height, rapidly increases. Physical reasons for the above effect are inspected

  10. Arthroscopic assisted tendon reconstruction for triangular fibrocartilage complex irreparable tears.

    Science.gov (United States)

    Luchetti, R; Atzei, A

    2017-05-01

    We report our 11-year experience of performing arthroscopically assisted triangular fibrocartilage complex reconstruction in the treatment of chronic distal radio-ulnar joint instability resulting from irreparable triangular fibrocartilage complex injuries. Eleven patients were treated. Three skin incisions were made in order to create radial and ulna tunnels for passage of the tendon graft, which is used to reconstruct the dorsal and palmar radio-ulnar ligaments, under fluoroscopic and arthroscopic guidance. At a mean follow-up of 68 months all but one had a stable distal radio-ulnar joint. Pain and grip strength, Mayo wrist score, Disability of the Arm Hand and Shoulder and patient-rated wrist and hand evaluation scores improved. The ranges of forearm rotation remained largely unchanged. Complications included an early tendon graft tear, two late-onset graft ruptures, one ulna styloid fracture during surgery and persistent wrist discomfort during forearm rotation requiring tendon graft revision in one case. An arthroscopic assisted approach for triangular fibrocartilage complex reconstruction appears safe and produces comparable results with the open technique. IV.

  11. MR imaging of the triangular fibrocartilage of the wrist

    International Nuclear Information System (INIS)

    Golimbu, C.N.; Firooznia, H.; Rafii, M.; Melone, C.; Leber, C.

    1988-01-01

    Magnetic resonance (MR) imaging of the wrist was performed in 25 patients who had pain or localized soft-tissue swelling in the ulnar side of the wrist. T1-weighted coronal images were obtained in all patients. In addition, coronal or axial images with T2-weighted or fast-field-echo sequences were obtained in 16 of these patients. MR imaging demonstrated tears of the triangular fibrocartilage of the wrist in 13 patients. Twelve of these tears were confirmed at surgery. In one patient, the triangular fibrocartilage was found at surgery to be stretched and folded on itself but not torn. This represents the one false-positive MR image in this group of patients. In 12 patients, the symptoms could be explained by a diversity of MR abnormalities, such as aseptic necrosis of carpal bones, subluxation of distal radioulnar joint, and synovitis of the tendon sheaths. MR imaging offers the advantage of investigating the triangular fibrocartilage of the wrist in a noninvasive manner; it may be used as a screening method in patients considered for surgery

  12. Modeling and Stability Analysis of Wedge Clutch System

    Directory of Open Access Journals (Sweden)

    Jian Yao

    2014-01-01

    Full Text Available A wedge clutch with unique features of self-reinforcement and small actuation force was designed. Its self-reinforcement feature, associated with different factors such as the wedge angle and friction coefficient, brings different dynamics and unstable problem with improper parameters. To analyze this system, a complete mathematical model of the actuation system is built, which includes the DC motor, the wedge mechanism, and the actuated clutch pack. By considering several nonlinear factors, such as the slip-stick friction and the contact or not of the clutch plates, the system is piecewise linear. Through the stability analysis of the linearized system in clutch slipping phase, the stable condition of the designed parameters is obtained as α>arctan⁡(μc. The mathematical model of the actuation system is validated by prototype testing. And with the validated model, the system dynamics in both stable and unstable conditions is investigated and discussed in engineering side.

  13. Multiple phases and vicious walkers in a wedge

    Directory of Open Access Journals (Sweden)

    Gesualdo Delfino

    2015-12-01

    Full Text Available We consider a statistical system in a planar wedge, for values of the bulk parameters corresponding to a first order phase transition and with boundary conditions inducing phase separation. Our previous exact field theoretical solution for the case of a single interface is extended to a class of systems, including the Blume–Capel model as the simplest representative, allowing for the appearance of an intermediate layer of a third phase. We show that the interfaces separating the different phases behave as trajectories of vicious walkers, and determine their passage probabilities. We also show how the theory leads to a remarkable form of wedge covariance, i.e. a relation between properties in the wedge and in the half plane, which involves the appearance of self-Fourier functions.

  14. Tax wedge in Croatia, Belgium, Estonia, Germany and Slovakia

    Directory of Open Access Journals (Sweden)

    Ana Gabrilo

    2016-06-01

    Full Text Available The aim of this paper is to analyse the taxation of labour income in Croatia, Belgium,Estonia, Germany and Slovakia. Having presented an outline of tax system rules, the paper shows the decomposition of the net average tax wedge for different family types and different income levels based on the OECD methodology. The results show that all observed countries apply a progressive tax schedule, apart from Germany where taxation for higher gross wages is not progressive due to a  cap on the SIC base. When it comes to a taxpayer earning an average gross wage, a Croatian single worker without children has the lowest tax burden, followed by Estonia, Slovakia, Germany and Belgium. However, as regards taxpayers earning 400% of AGW, Estonia has the smallest tax wedge, followed by Slovakia, Germany, Croatia and Belgium. Similar results are obtained by analyzing the tax wedge for couples with two children where one spouse is out of work.

  15. New Transition Wedge Design Composed by Prefabricated Reinforced Concrete Slabs

    Directory of Open Access Journals (Sweden)

    Julia Real-Herráiz

    Full Text Available Abstract Important track degradation occurs in structure-embankment transitions, in which an abrupt change in track vertical stiffness arises, leading to a reduction in passengers comfort and safety. Although granular wedges are suggested by different railroad administrations as a solution to avoid these problems, they present some disadvantages which may affect track long-term performance. In this paper, a new solution designed with prefabricated reinforced concrete slabs is proposed. The aim of this solution is to guarantee a continuous and gradual track vertical stiffness transition in the vicinity of structures, overcoming granular wedges disadvantages. The aim of this study is to assess the performance of the novel wedge design by means of a 3-D FEM model and to compare it with the current solution.

  16. Capillary surfaces in a wedge: Differing contact angles

    Science.gov (United States)

    Concus, Paul; Finn, Robert

    1994-01-01

    The possible zero-gravity equilibrium configurations of capillary surfaces u(x, y) in cylindrical containers whose sections are (wedge) domains with corners are investigated mathematically, for the case in which the contact angles on the two sides of the wedge may differ. In such a situation the behavior can depart in significant qualitative ways from that for which the contact angles on the two sides are the same. Conditions are described under which such qualitative changes must occur. Numerically computed surfaces are depicted to indicate the behavior.

  17. Three-dimensional wedge filling in ordered and disordered systems

    International Nuclear Information System (INIS)

    Greenall, M J; Parry, A O; Romero-Enrique, J M

    2004-01-01

    We investigate interfacial structural and fluctuation effects occurring at continuous filling transitions in 3D wedge geometries. We show that fluctuation-induced wedge covariance relations that have been reported recently for 2D filling and wetting have mean-field or classical analogues that apply to higher-dimensional systems. Classical wedge covariance emerges from analysis of filling in shallow wedges based on a simple interfacial Hamiltonian model and is supported by detailed numerical investigations of filling within a more microscopic Landau-like density functional theory. Evidence is presented that classical wedge covariance is also obeyed for filling in more acute wedges in the asymptotic critical regime. For sufficiently short-ranged forces mean-field predictions for the filling critical exponents and covariance are destroyed by pseudo-one-dimensional interfacial fluctuations. We argue that in this filling fluctuation regime the critical exponents describing the divergence of length scales are related to values of the interfacial wandering exponent ζ(d) defined for planar interfaces in (bulk) two-dimensional (d = 2) and three-dimensional (d = 3) systems. For the interfacial height l w ∼ θ-α) -β w , with θ the contact angle and α the wedge tilt angle, we find β w = ζ(2)/2(1-ζ(3)). For pure systems (thermal disorder) we recover the known result β w = 1/4 predicted by interfacial Hamiltonian studies whilst for random-bond disorder we predict the universal critical exponent β ∼ even in the presence of dispersion forces. We revisit the transfer matrix theory of three-dimensional filling based on an effective interfacial Hamiltonian model and discuss the interplay between breather, tilt and torsional interfacial fluctuations. We show that the coupling of the modes allows the problem to be mapped onto a quantum mechanical problem as conjectured by previous authors. The form of the interfacial height probability distribution function predicted by

  18. Tool life of ceramic wedges during precise turning of tungsten

    Directory of Open Access Journals (Sweden)

    Legutko Stanislaw

    2017-01-01

    Full Text Available Properties, application and machinability of tungsten and its alloys have been demonstrated. The comparison of the tool life and wear of the wedges made of SiAlON and whisker ceramics during the precise turning at different cutting parameters have been presented. The CNC lathe DMG CTX 310 Ecoline and tungsten of 99.7 % purity were used during the experiments. Only the wedge of whisker ceramics has proved to be sufficiently suitable and only for relatively low cutting speeds.

  19. Mantle wedge infiltrated with saline fluids from dehydration and decarbonation of subducting slab.

    Science.gov (United States)

    Kawamoto, Tatsuhiko; Yoshikawa, Masako; Kumagai, Yoshitaka; Mirabueno, Ma Hannah T; Okuno, Mitsuru; Kobayashi, Tetsuo

    2013-06-11

    Slab-derived fluids play an important role in heat and material transfer in subduction zones. Dehydration and decarbonation reactions of minerals in the subducting slab have been investigated using phase equilibria and modeling of fluid flow. Nevertheless, direct observations of the fluid chemistry and pressure-temperature conditions of fluids are few. This report describes CO2-bearing saline fluid inclusions in spinel-harzburgite xenoliths collected from the 1991 Pinatubo pumice deposits. The fluid inclusions are filled with saline solutions with 5.1 ± 1.0% (wt) NaCl-equivalent magnesite crystals, CO2-bearing vapor bubbles, and a talc and/or chrysotile layer on the walls. The xenoliths contain tremolite amphibole, which is stable in temperatures lower than 830 °C at the uppermost mantle. The Pinatubo volcano is located at the volcanic front of the Luzon arc associated with subduction of warm oceanic plate. The present observation suggests hydration of forearc mantle and the uppermost mantle by slab-derived CO2-bearing saline fluids. Dehydration and decarbonation take place, and seawater-like saline fluids migrate from the subducting slab to the mantle wedge. The presence of saline fluids is important because they can dissolve more metals than pure H2O and affect the chemical evolution of the mantle wedge.

  20. Flow Analysis for the Falkner–Skan Wedge Flow

    DEFF Research Database (Denmark)

    Bararnia, H; Haghparast, N; Miansari, M

    2012-01-01

    In this article an analytical technique, namely the homotopy analysis method (HAM), is applied to solve the momentum and energy equations in the case of a two-dimensional incompressible flow passing over a wedge. The trail and error method and Padé approximation strategies have been used to obtai...

  1. Dependence of wedge transmission factor on co-60 teletherapy ...

    African Journals Online (AJOL)

    Measuring the wedge factor (WF) for radiation field of 10 x 10 cm2 at a specified depth and Source to Surface Distance (SSD), and applying the value to all treatment depths and technique could introduce errors > ± 5 % of threshold stipulated for patient radiation dose delivery. Therefore, some Treatment Planning Systems ...

  2. Thoracoscopic pulmonary wedge resection without post-operative chest drain

    DEFF Research Database (Denmark)

    Holbek, Bo Laksafoss; Hansen, Henrik Jessen; Kehlet, Henrik

    2016-01-01

    %) patients had a pneumothorax of mean size 12 ± 12 mm on supine 8-h post-operative X-ray for which the majority resolved spontaneously within 2-week control. There were no complications on 30-day follow-up. Median length of stay was 1 day. CONCLUSIONS: The results support that VATS wedge resection...

  3. Fixed Points of Maps of a Nonaspherical Wedge

    Directory of Open Access Journals (Sweden)

    Merrill Keith

    2009-01-01

    Full Text Available Abstract Let be a finite polyhedron that has the homotopy type of the wedge of the projective plane and the circle. With the aid of techniques from combinatorial group theory, we obtain formulas for the Nielsen numbers of the selfmaps of .

  4. Complex Wedge-Shaped Matrices: A Generalization of Jacobi Matrices

    Czech Academy of Sciences Publication Activity Database

    Hnětynková, Iveta; Plešinger, M.

    2015-01-01

    Roč. 487, 15 December (2015), s. 203-219 ISSN 0024-3795 R&D Projects: GA ČR GA13-06684S Keywords : eigenvalues * eigenvector * wedge-shaped matrices * generalized Jacobi matrices * band (or block) Krylov subspace methods Subject RIV: BA - General Mathematics Impact factor: 0.965, year: 2015

  5. The Hardy inequality and the heat flow in curved wedges

    Czech Academy of Sciences Publication Activity Database

    Krejčiřík, David

    2016-01-01

    Roč. 73, č. 2 (2016), s. 91-113 ISSN 0032-5155 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : Hardy inequality * heat equation * large-time behaviour * curved wedges * Dirichlet Laplacian * conical singularities * Brownian motion * subcriticality Subject RIV: BE - Theoretical Physics Impact factor: 0.735, year: 2016

  6. Therapy by stationary photon fields from a 42 MeV betatron using wedge filters

    International Nuclear Information System (INIS)

    Wicke, L.; Kaercher, K.H.; Naesiger, H.; Prokosch, E.; Vienna Univ.

    1975-01-01

    The dose distribution in photon beams from a 42 MeV betatron using wedge filters of lead with different angles of slope is described. The wedge coefficient to be considered at a field size of 10 x 10 cm is given. The scope for isodoses modified by wedge filters is discussed with regard to stationary-field photon therapy. (orig.) [de

  7. A practical method to calculate head scatter factors in wedged rectangular and irregular MLC shaped beams for external and internal wedges

    International Nuclear Information System (INIS)

    Georg, Dietmar; Olofsson, Joergen; Kuenzler, Thomas; Aiginger, Hannes; Karlsson, Mikael

    2004-01-01

    Factor based methods for absorbed dose or monitor unit calculations are often based on separate data sets for open and wedged beams. The determination of basic beam parameters can be rather time consuming, unless equivalent square methods are applied. When considering irregular wedged beams shaped with a multileaf collimator, parametrization methods for dosimetric quantities, e.g. output ratios or wedge factors as a function of field size and shape, become even more important. A practical method is presented to derive wedged output ratios in air (S c,w ) for any rectangular field and for any irregular MLC shaped beam. This method was based on open field output ratios in air (S c ) for a field with the same collimator setting, and a relation f w between S c,w and S c . The relation f w can be determined from measured output ratios in air for a few open and wedged fields including the maximum wedged field size. The function f w and its parametrization were dependent on wedge angle and treatment head design, i.e. they were different for internal and external wedges. The proposed method was tested for rectangular wedged fields on three accelerators with internal wedges (GE, Elekta, BBC) and two accelerators with external wedges (Varian). For symmetric regular beams the average deviation between calculated and measured S c,w /S c ratios was 0.3% for external wedges and about 0.6% for internal wedges. Maximum deviations of 1.8% were obtained for elongated rectangular fields on the GE and ELEKTA linacs with an internal wedge. The same accuracy was achieved for irregular MLC shaped wedged beams on the accelerators with MLC and internal wedges (GE and Elekta), with an average deviation <1% for the fields tested. The proposed method to determine output ratios in air for wedged beams from output ratios of open beams, combined with equivalent square approaches, can be easily integrated in empirical or semi-empirical methods for monitor unit calculations

  8. Collapse of triangular channels in a soft elastomer

    Science.gov (United States)

    Tepáyotl-Ramírez, Daniel; Lu, Tong; Park, Yong-Lae; Majidi, Carmel

    2013-01-01

    We extend classical solutions in contact mechanics to examine the collapse of channels in a soft elastomer. These channels have triangular cross-section and collapse when pressure is applied to the surrounding elastomer. Treating the walls of the channel as indenters that penetrate the channel base, we derive an algebraic mapping between pressure and cross-sectional area. These theoretical predictions are in strong agreement with results that we obtain through finite element analysis and experimental measurements. This is accomplished without data fitting and suggests that the theoretical approach may be generalized to a broad range of cross-sectional geometries in soft microfluidics.

  9. The spatially anisotropic triangular lattice antiferromagnet: Popov-Fedotov method

    International Nuclear Information System (INIS)

    Nga, Pham Thi Thanh; Trang, Phan Thu; Thang, Nguyen Toan

    2017-01-01

    We present an analysis of the antiferromagnetic Heisenberg model on an triangular lattice with spatially anisotropic J 1 - J 2 exchange interactions. We apply the Popov-Fedotov method based on introducing an imaginary valued chemical potential to enforce the auxiliary fermion constraint exactly. The staggered magnetization, magnon spectra, free energy are computed in one loop approximation and compared using two different constraints: exact and on average. In the limit of zero temperature the results are identical, whereas at higher temperature significant differences are found. The comparisons with the results obtained by other methods are discussed. (paper)

  10. The Hill-determinant perturbation theory with triangular propagators

    International Nuclear Information System (INIS)

    Znojil, M.

    1996-01-01

    A new version of the Rayleigh-Schroedinger perturbation prescription is proposed. Its main formal feature lies in an unusual choice of the model space and unperturbed H 0 and in a resulting lower-triangular matrix structure of its propagators. Within the framework of the so-called Hill-determinant method, an admissibility of any incompletely solvable zero-order Hamiltonian is achieved in this way. As a consequence, the range of practical applicability of our new perturbative formalism may be expected to incorporate many new phenomenological interactions with a strongly anharmonic character. 18 refs

  11. Bistable Chimera Attractors on a Triangular Network of Oscillator Populations

    DEFF Research Database (Denmark)

    Martens, Erik Andreas

    2010-01-01

    . This triangular network is the simplest discretization of a continuous ring of oscillators. Yet it displays an unexpectedly different behavior: in contrast to the lone stable chimera observed in continuous rings of oscillators, we find that this system exhibits two coexisting stable chimeras. Both chimeras are......, as usual, born through a saddle-node bifurcation. As the coupling becomes increasingly local in nature they lose stability through a Hopf bifurcation, giving rise to breathing chimeras, which in turn get destroyed through a homoclinic bifurcation. Remarkably, one of the chimeras reemerges by a reversal...

  12. A flat triangular shell element with Loof nodes

    DEFF Research Database (Denmark)

    Poulsen, Peter Noe; Damkilde, Lars

    1996-01-01

    In the formulation of flat shell elements it is difficult to achieve inter-element compatibility between membrane and transverse displacements for non-coplanar elements. Many elements lack proper nodal degrees of freedom to model intersections making the assembly of elements troublesome. A flat...... triangular shell element is established by a combination of a new plate bending element DKTL and the well-known linear membrane strain element LST, and for this element the above-mentioned deficiences are avoided. The plate bending element DKTL is based on Discrete Kirchhoff Theory and Loof nodes. The nodal...

  13. Arthroscopic Management of Triangular Fibrocartilage Complex Peripheral Injury.

    Science.gov (United States)

    Haugstvedt, Jan Ragnar; Søreide, Endre

    2017-11-01

    Patients suffering from ulnar-sided wrist pain after trauma may develop tenderness, clicking, a positive fovea sign, or instability of the distal radioulnar joint. If the pain is persistent, conservative treatment does not help, and the patient agrees to surgery, arthroscopy may reveal a triangular fibrocartilage complex (TFCC) injury with capsular detachment, foveal avulsion, or a combination thereof. Capsular reattachment is possible using an arthroscopic assisted technique. The reattachment can be performed with an inside-out, outside-in, or all-inside technique, providing good to excellent results, which tend to persist over time, in 60% to 90% of cases. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Arthroscopic Management of Triangular Fibrocartilage Complex Foveal Injury.

    Science.gov (United States)

    Fujio, Keiji

    2017-11-01

    The deep component of triangular fibrocartilage complex (TFCC) inserts onto the fovea of the ulnar head. This component is critical to provide distal radioulnar joint stability. The surgical techniques and results of transosseous inside-out TFCC foveal repair are discussed. The rewarding results encouraged the repair of TFCC to the fovea arthroscopically. Although the results are good, the factors of age (traumatic or degenerative) and quality of stump and TFCC proper, which relate to the results should be considered in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Diagnosis of triangular fibrocartilage complex injury using arthrography and MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Kiyonobu; Soejima, Osamu; Naito, Masatoshi [Fukuoka Univ. (Japan). School of Medicine

    2001-09-01

    Twenty patients (twenty-one wrists) with chronic ulnar wrist pain who had undergone radiocarpal arthrography and MRI before arthroscopic examination were evaluated to determine the usefulness of these preoperative diagnostic procedures (arthrogrphy and MRI) for the detection of triangular fibrocartilage complex (TFCC) injury. Based on the arthroscopic findings, the sensitivity and specificity of arthrography were 63% and 100% respectively for detecting TFCC lesions, while they were 68% and 50% respectively for MRI. Although no significant superiority was observed between arthrography and MRI in this study, further improrumchts in the preoperative diagnostic procedures are still needed in order to more accurately detect TFCC injuries. (author)

  16. Collective impurity effects in the Heisenberg triangular antiferromagnet

    International Nuclear Information System (INIS)

    Maryasin, V S; Zhitomirsky, M E

    2015-01-01

    We theoretically investigate the Heisenberg antiferromagnet on a triangular lattice doped with nonmagnetic impurities. Two nontrivial effects resulting from collective impurity behavior are predicted. The first one is related to presence of uncompensated magnetic moments localized near vacancies as revealed by the low-temperature Curie tail in the magnetic susceptibility. These moments exhibit an anomalous growth with the impurity concentration, which we attribute to the clustering mechanism. In an external magnetic field, impurities lead to an even more peculiar phenomenon lifting the classical ground-state degeneracy in favor of the conical state. We analytically demonstrate that vacancies spontaneously generate a positive biquadratic exchange, which is responsible for the above degeneracy lifting

  17. Triangular and Trapezoidal Fuzzy State Estimation with Uncertainty on Measurements

    Directory of Open Access Journals (Sweden)

    Mohammad Sadeghi Sarcheshmah

    2012-01-01

    Full Text Available In this paper, a new method for uncertainty analysis in fuzzy state estimation is proposed. The uncertainty is expressed in measurements. Uncertainties in measurements are modelled with different fuzzy membership functions (triangular and trapezoidal. To find the fuzzy distribution of any state variable, the problem is formulated as a constrained linear programming (LP optimization. The viability of the proposed method would be verified with the ones obtained from the weighted least squares (WLS and the fuzzy state estimation (FSE in the 6-bus system and in the IEEE-14 and 30 bus system.

  18. Triangular preconditioners for saddle point problems with a penalty term

    Energy Technology Data Exchange (ETDEWEB)

    Klawonn, A. [Westfaelische Wilhelms-Universitaet, Muenster (Germany)

    1996-12-31

    Triangular preconditioners for a class of saddle point problems with a penalty term are considered. An important example is the mixed formulation of the pure displacement problem in linear elasticity. It is shown that the spectrum of the preconditioned system is contained in a real, positive interval, and that the interval bounds can be made independent of the discretization and penalty parameters. This fact is used to construct bounds of the convergence rate of the GMRES method used with an energy norm. Numerical results are given for GMRES and BI-CGSTAB.

  19. Automatic Shape Control of Triangular B-Splines of Arbitrary Topology

    Institute of Scientific and Technical Information of China (English)

    Ying He; Xian-Feng Gu; Hong Qin

    2006-01-01

    Triangular B-splines are powerful and flexible in modeling a broader class of geometric objects defined over arbitrary, non-rectangular domains. Despite their great potential and advantages in theory, practical techniques and computational tools with triangular B-splines are less-developed. This is mainly because users have to handle a large number of irregularly distributed control points over arbitrary triangulation. In this paper, an automatic and efficient method is proposed to generate visually pleasing, high-quality triangular B-splines of arbitrary topology. The experimental results on several real datasets show that triangular B-splines are powerful and effective in both theory and practice.

  20. On the interference rejection capabilities of triangular antenna array for cellular base stations

    KAUST Repository

    Atat, Rachad; Shakir, Muhammad; Alouini, Mohamed-Slim

    2012-01-01

    In this paper, we present the performance analysis of the triangular antenna arrays in terms of the interference rejection capability. In this context, we derive an expression to calculate the spatial interference suppression coefficient for the triangular antenna array with variable number of antenna elements. The performance of the triangular antenna array has been compared with the circular antenna array with respect to interference suppression performance, steering beam pattern, beamwidth and directivity. Simulation results show that the triangular array with large number of elements produces a sharper beamwidth and better interference suppression performance than the circular antenna array. © 2012 IEEE.

  1. On the interference rejection capabilities of triangular antenna array for cellular base stations

    KAUST Repository

    Atat, Rachad

    2012-03-01

    In this paper, we present the performance analysis of the triangular antenna arrays in terms of the interference rejection capability. In this context, we derive an expression to calculate the spatial interference suppression coefficient for the triangular antenna array with variable number of antenna elements. The performance of the triangular antenna array has been compared with the circular antenna array with respect to interference suppression performance, steering beam pattern, beamwidth and directivity. Simulation results show that the triangular array with large number of elements produces a sharper beamwidth and better interference suppression performance than the circular antenna array. © 2012 IEEE.

  2. IN SEARCH OF IDEAL FORM- RATIO OF TRIANGULAR CHANNEL

    Directory of Open Access Journals (Sweden)

    B. C. DAS

    2014-11-01

    Full Text Available In Search of Ideal Form-Ratio of Triangular Channel. Cross-sectional form of a natural channel is a two dimensional variable which is thoroughly studied by scholars from different fields on natural sciences like hydrology, geology, geomorphology, etc. Average river channels tend to develop their channel-cross sectional form in a way to produce an approximate equilibrium between the channel and the water and sediment it transport. But how far it is deviated from the ideal cross-sectional form can only be determined by knowing the ideal form which was calculated by Hickin for rectangular channel. This ideal cross-sectional form of ‘maximum efficiency’ is virtually a theoretical one and attaining of which the river transports its water and load with least friction with its bed. ‘Ideal form ratio’ provides numerical tools for triangular channel to determine the degree of deviation of a cross-sectional form from that of an ideal one.

  3. Corrosion processes of triangular silver nanoparticles compared to bulk silver

    Energy Technology Data Exchange (ETDEWEB)

    Keast, V. J., E-mail: vicki.keast@newcastle.edu.au; Myles, T. A. [University of Newcastle, School of Mathematical and Physical Sciences (Australia); Shahcheraghi, N.; Cortie, M. B. [University of Technology Sydney, Institute for Nanoscale Technology (Australia)

    2016-02-15

    Excessive corrosion of silver nanoparticles is a significant impediment to their use in a variety of potential applications in the biosensing, plasmonic and antimicrobial fields. Here we examine the environmental degradation of triangular silver nanoparticles (AgNP) in laboratory air. In the early stages of corrosion, transmission electron microscopy shows that dissolution of the single-crystal, triangular, AgNP (side lengths 50–120 nm) is observed with the accompanying formation of smaller, polycrystalline Ag particles nearby. The new particles are then observed to corrode to Ag{sub 2}S and after 21 days nearly full corrosion has occurred, but some with minor Ag inclusions remaining. In contrast, a bulk Ag sheet, studied in cross section, showed an adherent corrosion layer of only around 20–50 nm in thickness after over a decade of being exposed to ambient air. The results have implications for antibacterial properties and ecotoxicology of AgNP during corrosion as the dissolution and reformation of Ag particles during corrosion will likely be accompanied by the release of Ag{sup +} ions.

  4. High magnetic field magnetization of a new triangular lattice antiferromagnet

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, H. D. [Univ. of Tennessee, Knoxville, TN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States). National High Magnetic Field Lab. (MagLab); Stritzinger, Laurel Elaine Winter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Harrison, Neil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-23

    In CsV(MoO4)2, the magnetic V3+ ions with octahedral oxygen-coordination form a geometrically frustrated triangular lattice. So fare, there is no magnetic properties reported on it. Recently, we successfully grew single crystals of CsV(MoO4)2 by using flux method. The susceptibility shows a sharp drop around 24 K, representing a long range magnetic ordering. To understand the physical properties of this new triangular lattice antiferromagnet (TLAF), we pursued high field magnetization measurements to answer two questions: (i) what is the saturation field, which will be very useful to calculate the exchange interaction of the system? (ii) Will it exhibit spin state transition, such as the up up down phase with 1/3-saturation moment as other TLAFs? Recently, we performed VSM measurements in Cell 8, Tallahassee, NHMFL, the results show that the magnetization reaches 0.38 MuB at 34 T, which is just 19% of the full moment of 2 MuB for V3+ (3d2) ions. Apparently we need higher field to reach 1/3 value or full moment.

  5. Triangular Geometrized Sampling Heuristics for Fast Optimal Motion Planning

    Directory of Open Access Journals (Sweden)

    Ahmed Hussain Qureshi

    2015-02-01

    Full Text Available Rapidly-exploring Random Tree (RRT-based algorithms have become increasingly popular due to their lower computational complexity as compared with other path planning algorithms. The recently presented RRT* motion planning algorithm improves upon the original RRT algorithm by providing optimal path solutions. While RRT determines an initial collision-free path fairly quickly, RRT* guarantees almost certain convergence to an optimal, obstacle-free path from the start to the goal points for any given geometrical environment. However, the main limitations of RRT* include its slow processing rate and high memory consumption, due to the large number of iterations required for calculating the optimal path. In order to overcome these limitations, we present another improvement, i.e, the Triangular Geometerized-RRT* (TG-RRT* algorithm, which utilizes triangular geometrical methods to improve the performance of the RRT* algorithm in terms of the processing time and a decreased number of iterations required for an optimal path solution. Simulations comparing the performance results of the improved TG-RRT* with RRT* are presented to demonstrate the overall improvement in performance and optimal path detection.

  6. Experimental investigation of sound absorption of acoustic wedges for anechoic chambers

    Science.gov (United States)

    Belyaev, I. V.; Golubev, A. Yu.; Zverev, A. Ya.; Makashov, S. Yu.; Palchikovskiy, V. V.; Sobolev, A. F.; Chernykh, V. V.

    2015-09-01

    The results of measuring the sound absorption by acoustic wedges, which were performed in AC-3 and AC-11 reverberation chambers at the Central Aerohydrodynamic Institute (TsAGI), are presented. Wedges of different densities manufactured from superfine basaltic and thin mineral fibers were investigated. The results of tests of these wedges were compared to the sound absorption of wedges of the operating AC-2 anechoic facility at TsAGI. It is shown that basaltic-fiber wedges have better sound-absorption characteristics than the investigated analogs and can be recommended for facing anechoic facilities under construction.

  7. The optimisation of wedge filters in radiotherapy of the prostate

    International Nuclear Information System (INIS)

    Oldham, Mark; Neal, Anthony J.; Webb, Steve

    1995-01-01

    A treatment plan optimisation algorithm has been applied to 12 patients with early prostate cancer in order to determine the optimum beam-weights and wedge angles for a standard conformal three-field treatment technique. The optimisation algorithm was based on fast-simulated-annealing using a cost function designed to achieve a uniform dose in the planning-target-volume (PTV) and to minimise the integral doses to the organs-at-risk. The algorithm has been applied to standard conformal three-field plans created by an experienced human planner, and run in three PLAN MODES: (1) where the wedge angles were fixed by the human planner and only the beam-weights were optimised; (2) where both the wedge angles and beam-weights were optimised; and (3) where both the wedge angles and beam-weights were optimised and a non-uniform dose was prescribed to the PTV. In the latter PLAN MODE, a uniform 100% dose was prescribed to all of the PTV except for that region that overlaps with the rectum where a lower (e.g., 90%) dose was prescribed. The resulting optimised plans have been compared with those of the human planner who found beam-weights by conventional forward planning techniques. Plans were compared on the basis of dose statistics, normal-tissue-complication-probability (NTCP) and tumour-control-probability (TCP). The results of the comparison showed that all three PLAN MODES produced plans with slightly higher TCP for the same rectal NTCP, than the human planner. The best results were observed for PLAN MODE 3, where an average increase in TCP of 0.73% (± 0.20, 95% confidence interval) was predicted by the biological models. This increase arises from a beneficial dose gradient which is produced across the tumour. Although the TCP gain is small it comes with no increase in treatment complexity, and could translate into increased cures given the large numbers of patients being referred. A study of the beam-weights and wedge angles chosen by the optimisation algorithm revealed

  8. Variation in Depth Dose Data between Open and Wedge Fields for 6 MV X-Rays

    International Nuclear Information System (INIS)

    U, Hong; Ryu, M. S. Samuel; Park, In Kyu

    1989-01-01

    Central axis depth dose data for 6 MV X-rays, including tissue maximum ratios, were measured for wedge fields according to Tatcher equation. In wedge fields, the differences in magnitude which increased with depth, field size, and wedge thickness increased when compared with the corresponding open field data. However, phantom scatter correction factors for wedge fields differed less that 1% from the corresponding open field factors. The differences in central axis percent depth dose between two types of fields indicated beam hardening by the wedge filter. The deviation of percent depth doses and scatter correction factors between the effective wedge field and the nominal wedge field at same angle was negligible. The differences were less than 3.26% between the nominal or effective wedge fields and the open fields for percent depth doses to the depth 7cm in 6cm x 6cm field. For larger (10cm x 10cm) field size, however, the deviation of percent depth doses between the nominal or effective wedge fields and the open fields were greater-dosimetric errors were 3.56% at depth 7cm and nearly 5.30% at 12cm. We suggest that the percent depth doses of individual wedge and wedge transmission factors should be considered for the dose calculation or monitor setting in the treatment of deep seated tumor

  9. Direct FVM Simulation for Sound Propagation in an Ideal Wedge

    Directory of Open Access Journals (Sweden)

    Hongyu Ji

    2016-01-01

    Full Text Available The sound propagation in a wedge-shaped waveguide with perfectly reflecting boundaries is one of the few range-dependent problems with an analytical solution. This provides a benchmark for the theoretical and computational studies on the simulation of ocean acoustic applications. We present a direct finite volume method (FVM simulation for the ideal wedge problem, and both time and frequency domain results are analyzed. We also study the broadband problem with large-scale parallel simulations. The results presented in this paper validate the accuracy of the numerical techniques and show that the direct FVM simulation could be applied to large-scale complex acoustic applications with a high performance computing platform.

  10. Field size dependence of wedge factor: miniphantom vs full phantom measurements

    International Nuclear Information System (INIS)

    Allen Li, X.; Szanto, J.; Soubra, M.; Gerig, L. H.

    1995-01-01

    It is empirically known that the transmission factor for wedge in a high-energy photon beam is dependent upon field size and depth of measurement. The field-size dependence of wedge factors may be attributed to changes in (i) head scatter, (ii) phantom scatter, and (iii) backscatter from the wedge into the linac monitor chamber. In this work we present the results of studies designed to examine each of these factors in isolation. The wedge factors for wedges with nominal wedge angles of 15 deg. , 30 deg. , 45 deg. and 60 deg. were measured with a 3-g/cm 2 -diameter narrow cylindrical phantom (miniphantom), a brass cap with 1.5-g/cm 2 side-wall thickness and a full water phantom for 6-, 10- and 18-MV photon beams. The measurements were performed with and without flattening filter in place. The wedge factors measured with the miniphantom and the brass cap exclude the phantom scatter contribution. It has been found that the field-size behaviour of wedge factor measured with full water phantom is similar to that measured with the miniphantom and cap. This indicates that the head scatter radiation is the major contributor to the field size dependence of wedge factors. Wedge factors measured with water phantom are up to 5.0% smaller than those measured with miniphantom. This difference increases with wedge angle. When Measured with the flattening filter removed, the field size dependence of the wedge factor is reduced. This justify that the flattening filter is one of the major contributors to head scatters. The measurement results made with the brass cap agree well with those made by using the miniphantom. By measuring the monitor chamber output, it is found that the backscatters from the wedge into the linac ion chamber have little effect on the field size dependence of the wedge factor

  11. Interpretation and inverse analysis of the wedge splitting test

    DEFF Research Database (Denmark)

    Østergaard, Lennart; Stang, Henrik

    2002-01-01

    to the wedge splitting test and that it is well suited for the interpretation of test results in terms of s(w). A fine agreement between the hinge and FEM-models has been found. It has also been found that the test and the hinge model form a solid basis for inverse analysis. The paper also discusses possible...... three dimensional problems in the experiment as well as the influence of specimen size....

  12. New Transition Wedge Design Composed by Prefabricated Reinforced Concrete Slabs

    OpenAIRE

    Real-Herráiz, Julia; Zamorano-Martín, Clara; Real-Herráiz, Teresa; Morales-Ivorra, Silvia

    2016-01-01

    [EN] Important track degradation occurs in structure-embankment transitions, in which an abrupt change in track vertical stiffness arises, leading to a reduction in passengers comfort and safety. Although granular wedges are suggested by different railroad administrations as a solution to avoid these problems, they present some disadvantages which may affect track long-term performance. In this paper, a new solution designed with prefabricated reinforced concrete slabs is proposed. The aim of...

  13. Partially wedged beams improve radiotherapy treatment of urinary bladder cancer

    International Nuclear Information System (INIS)

    Muren, Ludvig Paul; Hafslund, Rune; Gustafsson, Anders; Smaaland, Rune; Dahl, Olav

    2001-01-01

    Background and purpose: Partially wedged beams (PWBs) having wedge in one part of the field only, can be shaped using dynamic jaw intensity modulation. The possible clinical benefit of PWBs was tested in treatment plans for muscle-infiltrating bladder cancer. Material and methods: Three-dimensional treatment plans for 25 bladder cancer patients were analyzed. The originally prescribed standard conformal four-field box technique, which includes the use of lateral ordinary wedge beams, was compared to a modified conformal treatment using customized lateral PWBs. In these modified treatment plans, only the anterior parts of the two lateral beams had a wedge. To analyze the potential clinical benefit of treatment with PWBs, treatment plans were scored and compared using both physical parameters and biological dose response models. One tumour control probability model and two normal tissue complication probability (NTCP) models were applied. Different parameters for normal tissue radiation tolerance presented in the literature were used. Results: By PWBs the dose homogeneity throughout the target volume was improved for all patients, reducing the average relative standard deviation of the target dose distribution from 2.3 to 1.8%. A consistent reduction in the maximum doses to surrounding normal tissue volumes was also found. The most notable improvement was demonstrated in the rectum where the volume receiving more than the prescribed tumour dose was halved. Treatment with PWBs would permit a target dose escalation of 2-6 Gy in several of the patients analyzed, without increasing the overall risk for complications. The number of patients suitable for dose escalation ranged from 3 to 15, depending on whether support from all or only one of the five applied NTCP model/parameter combinations were required in each case to recommend dose escalation. Conclusion: PWBs represent a simple dose conformation tool that may allow radiation dose escalation in the treatment of muscle

  14. Spatial resolution of wedge shaped silicon microstrip detectors

    International Nuclear Information System (INIS)

    Anticic, T.; Barnett, B.; Blumenfeld, B.; Chien, C.Y.; Fisher, P.; Gougas, A.; Krizmanic, J.; Madansky, L.; Newman, D.; Orndorff, J.; Pevsner, A.; Spangler, J.

    1995-01-01

    Several wedge-shaped silicon microstrip detectors with pitches from 30 to 100 μm have been designed by our group and beam tested at the CERN SPS. We find the spatial resolution σ becomes larger at the rate of 0.21 μm per 1 μm increase in pitch, but the number of strips per cluster remains about the same as the pitch varies from 30 to 100 μm. (orig.)

  15. A paired wedge filter system for compensation in dose differences

    International Nuclear Information System (INIS)

    Kobayashi, H.; Sakurai, Y.; Kondo, S.; Abe, S.; Hayakawa, N.; Aoyama, Y.; Obata, Y.; Ishigaki, T.

    1998-01-01

    Objective: In radiotherapy, it is important to conform the high dose volume to the planned target volume. A variable thickness paired wedge filter system was developed to compensate for dose inhomogeneity arising from field width segment variation in conformal irradiation. Materials and methods: The present study used a 6 MV linear accelerator equipped with multileaf collimator leaves and a paired wedge compensating filter system. The dose variation due to field width was measured in each field segment width. The variation in attenuation of the compensators was measured as a function of filter position. As the field width increases, the relative absorbed dose also increases; this is the point of requiring compensation, so it can be in reverse proportion. Results: As the field width increases, the relative absorbed dose also increases; this is why compensation is required and thus it must be in reverse proportion. Attenuation of the absorbed dose by the paired filters was in proportion to the filter position. The filter position to compensate for the difference of absorbed doses was defined by the square root of the field width. For a field varying in width from 4 to 16 cm, the variation in the absorbed dose across the field was reduced from 12% to 2.7%. Conclusion: This paired wedge filter system reduced absorbed dose variations across multileaf collimator shaped fields and can facilitate treatment planning in conformal therapy. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  16. Indications, techniques, and outcomes of arthroscopic repair of scapholunate ligament and triangular fibrocartilage complex.

    Science.gov (United States)

    Mathoulin, C L

    2017-07-01

    This review includes updated understanding of the roles of intrinsic and extrinsic carpal ligaments in scapholunate instability and details the author's experience of indications, arthroscopic repair methods, and outcomes of treating the instability. A classification on triangular fibrocartilage complex injuries is reviewed, followed by author's indications, methods, and outcomes of arthroscopic repair of triangular fibrocartilage complex injuries.

  17. The Steiner ratio for points on a triangular lattice

    Directory of Open Access Journals (Sweden)

    PO de Wet

    2008-12-01

    Full Text Available The study of spanning trees and Steiner trees arises naturally in applications, such as in the design of integrated circuit boards, communication networks, power networks and pipelines of minimum cost. In such applications the Steiner ratio is an indication of how badly a minimum spanning tree performs compared to a Steiner minimal tree. In this paper a short proof is presented for the Steiner ratio for points on a triangular lattice in the Euclidean plane. A Steiner tree in two dimensions is "lifted" to become a rectilinear tree in three dimensions, where it is altered. The rectilinear tree is then projected back into the plane and the result readily follows. A short note at the end of the paper compares our three-dimensional rectilinear trees to "impossible objects" such as Escher's "Waterfall."

  18. Acoustic control study of turbofan nozzles with triangular chevrons

    Directory of Open Access Journals (Sweden)

    Grigore CICAN

    2014-03-01

    Full Text Available This paper has a small part dealing with the notion of chevron and the process that helps reducing the noise pollution. Based on the gas dynamics and the geometrical parameters of the turbofan jet engine a model of CFD data processing is created. In this process the influence of chevrons on acoustic wave intensity produced by the jet is observed by analyzing this process. A series of tests have been made on 10 si 20 lobed chevrons. The combination between them and the 7 resulting cases have been studied, namely the triangular chevrons in order to settle the influence of the geometrical parameters on the flow and on the jet acoustics. Finally the contribution of the chevrons in noise pollution reduction has been highlighted.

  19. GOMESH, Finite Elements Structure Plot with Triangular Mesh

    International Nuclear Information System (INIS)

    Draper, J.

    1977-01-01

    1 - Nature of the physical problem solved: Graphical representation of calculations on structures with finite subdivision. 2 - Method of solution: GOMESH treats meshes with triangular basic elements. The program uses the same punched cards as those required for the input to the 'STAG' series of stress analysis codes and can prepare three basic mesh diagrams which differ in their mode of numbering. One objective of using these diagrams is to show up errors in the card deck by making them visually recognisable. Furthermore, digital tests are made within the program to check that certain requirements have been observed in the production of the lattice. The program 'GOMESH', can provide, superimposed in the graphical representation, stress and temperature values in numerical form, can represent the displacement of the mesh before and after a specified irradiation time, and give the directions and sense of the principal stresses occurring in the individual elements, in the form of arrows of varying length

  20. Chronologic and Geographic Trends of Triangular Fibrocartilage Complex Repair.

    Science.gov (United States)

    Saito, Taichi; Sterbenz, Jennifer M; Chung, Kevin C

    2017-11-01

    This article shows trends in triangular fibrocartilage complex (TFCC) repair since 1990 by geographic area and year. The repair methods presented in the literature were inside-out, outside-in, all-inside, and open repair. The outside-in technique was reported most often for ulnar-side tears, whereas the inside-out technique was reported most frequently for radial-side tears. Recently, a foveal reattachment technique for ulnar-side tears has garnered attention and has been reported with increasing frequency, especially in Asia, because the deepest portion of TFCC, attached to fovea, plays a key role in stabilizing the distal radioulnar joint. Understanding these trends can help clinicians best treat TFCC tears. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Complex Anisotropic Structure of the Mantle Wedge Beneath Kamchatka Volcanoes

    Science.gov (United States)

    Levin, V.; Park, J.; Gordeev, E.; Droznin, D.

    2002-12-01

    A wedge of mantle material above the subducting lithospheric plate at a convergent margin is among the most dynamic environments of the Earth's interior. Deformation and transport of solid and volatile phases within this region control the fundamental process of elemental exchange between the surficial layers and the interior of the planet. A helpful property in the study of material deformation and transport within the upper mantle is seismic anisotropy, which may reflect both microscopic effects of preferentialy aligned crystals of olivine and orthopyroxene and macroscopic effects of systematic cracks, melt lenses, layering etc. Through the mapping of anisotropic properties within the mantle wedge we can establish patterns of deformation. Volatile content affects olivine alignment, so regions of anomalous volatile content may be evident. Indicators of seismic anisotropy commonly employed in upper mantle studies include shear wave birefringence and mode-conversion between compressional and shear body waves. When combined together, these techniques offer complementary constraints on the location and intensity of anisotropic properties. The eastern coast of southern Kamchatka overlies a vigorous convergent margin where the Pacific plate descends at a rate of almost 80 mm/yr towards the northwest. We extracted seismic anisotropy indicators from two data sets sensitive to the anisotropic properties of the uppermost mantle. Firstly, we evaluated teleseismic receiver functions for a number of sites, and found ample evidence for anisotropicaly-influenced P-to-S mode conversion. Secondly, we measured splitting in S waves of earthquakes with sources within the downgoing slab. The first set of observations provides constraints on the depth ranges where strong changes in anisotropic properties take place. The local splitting data provides constraints on the cumulative strength of anisotropic properties along specific pathways through the mantle wedge and possibly parts of

  2. Degradation and stabilization of ice wedges: Implications for assessing risk of thermokarst in northern Alaska

    Science.gov (United States)

    Kanevskiy, Mikhail; Shur, Yuri; Jorgenson, Torre; Brown, Dana R. N.; Moskalenko, Nataliya; Brown, Jerry; Walker, Donald A.; Raynolds, Martha K.; Buchhorn, Marcel

    2017-11-01

    Widespread degradation of ice wedges has been observed during the last decades in numerous areas within the continuous permafrost zone of Eurasia and North America. To study ice-wedge degradation, we performed field investigations at Prudhoe Bay and Barrow in northern Alaska during 2011-2016. In each study area, a 250-m transect was established with plots representing different stages of ice-wedge degradation/stabilization. Field work included surveying ground- and water-surface elevations, thaw-depth measurements, permafrost coring, vegetation sampling, and ground-based LiDAR scanning. We described cryostratigraphy of frozen soils and stable isotope composition, analyzed environmental characteristics associated with ice-wedge degradation and stabilization, evaluated the vulnerability and resilience of ice wedges to climate change and disturbances, and developed new conceptual models of ice-wedge dynamics that identify the main factors affecting ice-wedge degradation and stabilization and the main stages of this quasi-cyclic process. We found significant differences in the patterns of ice-wedge degradation and stabilization between the two areas, and the patterns were more complex than those previously described because of the interactions of changing topography, water redistribution, and vegetation/soil responses that can interrupt or reinforce degradation. Degradation of ice wedges is usually triggered by an increase in the active-layer thickness during exceptionally warm and wet summers or as a result of flooding or disturbance. Vulnerability of ice wedges to thermokarst is controlled by the thickness of the intermediate layer of the upper permafrost, which overlies ice wedges and protects them from thawing. In the continuous permafrost zone, degradation of ice wedges rarely leads to their complete melting; and in most cases wedges eventually stabilize and can then resume growing, indicating a somewhat cyclic and reversible process. Stabilization of ice wedges

  3. Realization of a Hole-Doped Mott Insulator on a Triangular Silicon Lattice

    Science.gov (United States)

    Ming, Fangfei; Johnston, Steve; Mulugeta, Daniel; Smith, Tyler S.; Vilmercati, Paolo; Lee, Geunseop; Maier, Thomas A.; Snijders, Paul C.; Weitering, Hanno H.

    2017-12-01

    The physics of doped Mott insulators is at the heart of some of the most exotic physical phenomena in materials research including insulator-metal transitions, colossal magnetoresistance, and high-temperature superconductivity in layered perovskite compounds. Advances in this field would greatly benefit from the availability of new material systems with a similar richness of physical phenomena but with fewer chemical and structural complications in comparison to oxides. Using scanning tunneling microscopy and spectroscopy, we show that such a system can be realized on a silicon platform. The adsorption of one-third monolayer of Sn atoms on a Si(111) surface produces a triangular surface lattice with half filled dangling bond orbitals. Modulation hole doping of these dangling bonds unveils clear hallmarks of Mott physics, such as spectral weight transfer and the formation of quasiparticle states at the Fermi level, well-defined Fermi contour segments, and a sharp singularity in the density of states. These observations are remarkably similar to those made in complex oxide materials, including high-temperature superconductors, but highly extraordinary within the realm of conventional s p -bonded semiconductor materials. It suggests that exotic quantum matter phases can be realized and engineered on silicon-based materials platforms.

  4. Shape-Dependent Electrocatalytic Reduction of CO2 to CO on Triangular Silver Nanoplates.

    Science.gov (United States)

    Liu, Subiao; Tao, Hongbiao; Zeng, Li; Liu, Qi; Xu, Zhenghe; Liu, Qingxia; Luo, Jing-Li

    2017-02-15

    Electrochemical reduction of CO 2 (CO 2 RR) provides great potential for intermittent renewable energy storage. This study demonstrates a predominant shape-dependent electrocatalytic reduction of CO 2 to CO on triangular silver nanoplates (Tri-Ag-NPs) in 0.1 M KHCO 3 . Compared with similarly sized Ag nanoparticles (SS-Ag-NPs) and bulk Ag, Tri-Ag-NPs exhibited an enhanced current density and significantly improved Faradaic efficiency (96.8%) and energy efficiency (61.7%), together with a considerable durability (7 days). Additionally, CO starts to be observed at an ultralow overpotential of 96 mV, further confirming the superiority of Tri-Ag-NPs as a catalyst for CO 2 RR toward CO formation. Density functional theory calculations reveal that the significantly enhanced electrocatalytic activity and selectivity at lowered overpotential originate from the shape-controlled structure. This not only provides the optimum edge-to-corner ratio but also dominates at the facet of Ag(100) where it requires lower energy to initiate the rate-determining step. This study demonstrates a promising approach to tune electrocatalytic activity and selectivity of metal catalysts for CO 2 RR by creating optimal facet and edge site through shape-control synthesis.

  5. Surface-Enhanced Raman Spectroscopy of Dye and Thiol Molecules Adsorbed on Triangular Silver Nano structures: A Study of Near-Field Enhancement, Localization of Hot-Spots, and Passivation of Adsorbed Carbonaceous Species

    International Nuclear Information System (INIS)

    Goncalves, M.R.; Marti, O.; Fabian Enderle, F.

    2012-01-01

    Surface-enhanced Raman spectroscopy (SERS) of thiols and dye molecules adsorbed on triangular silver nanostructures was investigated. The SERS hot-spots are localized at the edges and corners of the silver triangular particles. AFM and SEM measurements permit to observe many small clusters formed at the edges of triangular particles fabricated by nanosphere lithography. Finite-element calculations show that near-field enhancements can reach values of more than 200 at visible wavelengths, in the gaps between small spherical particles and large triangular particles, although for the later no plasmon resonance was found at the wavelengths investigated. The regions near the particles showing strong near-field enhancement are well correlated with spatial localization of SERS hot-spots done by confocal microscopy. Silver nanostructures fabricated by thermal evaporation present strong and fast fluctuating SERS activity, due to amorphous carbon contamination. Thiols and dye molecules seem to be able to passivate the undesired SERS activity on fresh evaporated silver. excitation: by far-field illumination of metal nanostructures or rough metal Raman scattering cross-section of gold-palladium target Temporal Fluctuation in SERS Temporal and spectral fluctuations.

  6. Rapid synthesis of triangular CdS nanocrystals without any trap emission

    International Nuclear Information System (INIS)

    Poulose, Aby Cheruvathoor; Veeranarayanan, Srivani; Yoshida, Yasuhiko; Maekawa, Toru; Sakthi Kumar, D.

    2012-01-01

    Nanocrystals (NCs) with anisotropic dimensions display polarized emission compared to nano dots. Triangular prisms are good candidates for polarized optical properties and monodisperse triangular NCs are ideal for developing building blocks for novel three-dimensional superlattices due to its anisotropic dimension. Among triangular nanocrystals, CdS nanocrystals are less discussed for the past one decade of research due to the difficulty in its processing method. Though well studied very few methods for developing CdS triangular nanocrystals have been reported, and most are having drawbacks either due to the time consuming process or the products are combination of triangular as well as many other shaped NC or with trap emissions due to defects which are comparable to band emissions limits its applications in full scale. Here, we are presenting a novel method to develop 7 nm CdS triangular NCs that can solve the above mentioned problems, which would augment the usage of CdS triangular crystals for many applications, based on its anisotropic properties.

  7. A novel method of the image processing on irregular triangular meshes

    Science.gov (United States)

    Vishnyakov, Sergey; Pekhterev, Vitaliy; Sokolova, Elizaveta

    2018-04-01

    The paper describes a novel method of the image processing based on irregular triangular meshes implementation. The triangular mesh is adaptive to the image content, least mean square linear approximation is proposed for the basic interpolation within the triangle. It is proposed to use triangular numbers to simplify using of the local (barycentric) coordinates for the further analysis - triangular element of the initial irregular mesh is to be represented through the set of the four equilateral triangles. This allows to use fast and simple pixels indexing in local coordinates, e.g. "for" or "while" loops for access to the pixels. Moreover, representation proposed allows to use discrete cosine transform of the simple "rectangular" symmetric form without additional pixels reordering (as it is used for shape-adaptive DCT forms). Furthermore, this approach leads to the simple form of the wavelet transform on triangular mesh. The results of the method application are presented. It is shown that advantage of the method proposed is a combination of the flexibility of the image-adaptive irregular meshes with the simple form of the pixel indexing in local triangular coordinates and the using of the common forms of the discrete transforms for triangular meshes. Method described is proposed for the image compression, pattern recognition, image quality improvement, image search and indexing. It also may be used as a part of video coding (intra-frame or inter-frame coding, motion detection).

  8. Classification of ulnar triangular fibrocartilage complex tears. A treatment algorithm for Palmer type IB tears.

    Science.gov (United States)

    Atzei, A; Luchetti, R; Garagnani, L

    2017-05-01

    The classical definition of 'Palmer Type IB' triangular fibrocartilage complex tear, includes a spectrum of clinical conditions. This review highlights the clinical and arthroscopic criteria that enable us to categorize five classes on a treatment-oriented classification system of triangular fibrocartilage complex peripheral tears. Class 1 lesions represent isolated tears of the distal triangular fibrocartilage complex without distal radio-ulnar joint instability and are amenable to arthroscopic suture. Class 2 tears include rupture of both the distal triangular fibrocartilage complex and proximal attachments of the triangular fibrocartilage complex to the fovea. Class 3 tears constitute isolated ruptures of the proximal attachment of the triangular fibrocartilage complex to the fovea; they are not visible at radio-carpal arthroscopy. Both Class 2 and Class 3 tears are diagnosed with a positive hook test and are typically associated with distal radio-ulnar joint instability. If required, treatment is through reattachment of the distal radio-ulnar ligament insertions to the fovea. Class 4 lesions are irreparable tears due to the size of the defect or to poor tissue quality and, if required, treatment is through distal radio-ulnar ligament reconstruction with tendon graft. Class 5 tears are associated with distal radio-ulnar joint arthritis and can only be treated with salvage procedures. This subdivision of type IB triangular fibrocartilage complex tear provides more insights in the pathomechanics and treatment strategies. II.

  9. Microtopographic control on the ground thermal regime in ice wedge polygons

    Science.gov (United States)

    Abolt, Charles J.; Young, Michael H.; Atchley, Adam L.; Harp, Dylan R.

    2018-06-01

    The goal of this research is to constrain the influence of ice wedge polygon microtopography on near-surface ground temperatures. Ice wedge polygon microtopography is prone to rapid deformation in a changing climate, and cracking in the ice wedge depends on thermal conditions at the top of the permafrost; therefore, feedbacks between microtopography and ground temperature can shed light on the potential for future ice wedge cracking in the Arctic. We first report on a year of sub-daily ground temperature observations at 5 depths and 9 locations throughout a cluster of low-centered polygons near Prudhoe Bay, Alaska, and demonstrate that the rims become the coldest zone of the polygon during winter, due to thinner snowpack. We then calibrate a polygon-scale numerical model of coupled thermal and hydrologic processes against this dataset, achieving an RMSE of less than 1.1 °C between observed and simulated ground temperature. Finally, we conduct a sensitivity analysis of the model by systematically manipulating the height of the rims and the depth of the troughs and tracking the effects on ice wedge temperature. The results indicate that winter temperatures in the ice wedge are sensitive to both rim height and trough depth, but more sensitive to rim height. Rims act as preferential outlets of subsurface heat; increasing rim size decreases winter temperatures in the ice wedge. Deeper troughs lead to increased snow entrapment, promoting insulation of the ice wedge. The potential for ice wedge cracking is therefore reduced if rims are destroyed or if troughs subside, due to warmer conditions in the ice wedge. These findings can help explain the origins of secondary ice wedges in modern and ancient polygons. The findings also imply that the potential for re-establishing rims in modern thermokarst-affected terrain will be limited by reduced cracking activity in the ice wedges, even if regional air temperatures stabilize.

  10. Modes of continental extension in a crustal wedge

    KAUST Repository

    Wu, Guangliang

    2015-07-01

    © 2015 Elsevier B.V. We ran numerical experiments of the extension of a crustal wedge as an approximation to extension in an orogenic belt or a continental margin. We study the effects of the strength of the lower crust and of a weak mid-crustal shear zone on the resulting extension styles. A weak mid-crustal shear zone effectively decouples upper crustal extension from lower crustal flow. Without the mid-crustal shear zone, the degree of coupling between the upper and the lower crust increases and extension of the whole crust tends to focus on the thickest part of the wedge. We identify three distinct modes of extension determined by the strength of the lower crust, which are characterized by 1) localized, asymmetric crustal exhumation in a single massif when the lower crust is weak, 2) the formation of rolling-hinge normal faults and the exhumation of lower crust in multiple core complexes with an intermediate strength lower crust, and 3) distributed domino faulting over the weak mid-crustal shear zone when the lower crust is strong. A frictionally stronger mid-crustal shear zone does not change the overall model behaviors but extension occurred over multiple rolling-hinges. The 3 modes of extension share characteristics similar to geological models proposed to explain the formation of metamorphic core complexes: 1) the crustal flow model for the weak lower crust, 2) the rolling-hinge and crustal flow models when the lower crust is intermediate and 3) the flexural uplift model when the lower crust is strong. Finally we show that the intensity of decoupling between the far field extension and lower crustal flow driven by the regional pressure gradient in the wedge control the overall style of extension in the models.

  11. Modes of continental extension in a crustal wedge

    KAUST Repository

    Wu, Guangliang; Lavier, Luc L.; Choi, Eunseo

    2015-01-01

    © 2015 Elsevier B.V. We ran numerical experiments of the extension of a crustal wedge as an approximation to extension in an orogenic belt or a continental margin. We study the effects of the strength of the lower crust and of a weak mid-crustal shear zone on the resulting extension styles. A weak mid-crustal shear zone effectively decouples upper crustal extension from lower crustal flow. Without the mid-crustal shear zone, the degree of coupling between the upper and the lower crust increases and extension of the whole crust tends to focus on the thickest part of the wedge. We identify three distinct modes of extension determined by the strength of the lower crust, which are characterized by 1) localized, asymmetric crustal exhumation in a single massif when the lower crust is weak, 2) the formation of rolling-hinge normal faults and the exhumation of lower crust in multiple core complexes with an intermediate strength lower crust, and 3) distributed domino faulting over the weak mid-crustal shear zone when the lower crust is strong. A frictionally stronger mid-crustal shear zone does not change the overall model behaviors but extension occurred over multiple rolling-hinges. The 3 modes of extension share characteristics similar to geological models proposed to explain the formation of metamorphic core complexes: 1) the crustal flow model for the weak lower crust, 2) the rolling-hinge and crustal flow models when the lower crust is intermediate and 3) the flexural uplift model when the lower crust is strong. Finally we show that the intensity of decoupling between the far field extension and lower crustal flow driven by the regional pressure gradient in the wedge control the overall style of extension in the models.

  12. Heat conduction problem of an evaporating liquid wedge

    Directory of Open Access Journals (Sweden)

    Tomas Barta

    2015-02-01

    Full Text Available We consider the stationary heat transfer near the contact line of an evaporating liquid wedge surrounded by the atmosphere of its pure vapor. In a simplified setting, the problem reduces to the Laplace equation in a half circle, subject to a non-homogeneous and singular boundary condition. By classical tools (conformal mapping, Green's function, we reformulate the problem as an integral equation for the unknown Neumann boundary condition in the setting of appropriate fractional Sobolev and weighted space. The unique solvability is then obtained by means of the Fredholm theorem.

  13. Preparation of triangular and hexagonal silver nanoplates on the surface of quartz substrate

    International Nuclear Information System (INIS)

    Jia Huiying; Zeng Jianbo; An Jing; Song Wei; Xu Weiqing; Zhao Bing

    2008-01-01

    In this paper, triangular and hexagonal silver nanoplates were prepared on the surface of quartz substrate using photoreduction of silver ions in the presence of silver seeds. The obtained silver nanoplates were characterized by atomic force microscopy and UV-vis spectroscopy. It was found that the silver seeds played an important role in the formation of triangular and hexagonal silver nanoplates. By varying the irradiation time, nanoplates with different sizes and shapes could be obtained. The growth mechanism for triangular and hexagonal nanoplates prepared on quartz substrate was discussed

  14. The Interval-Valued Triangular Fuzzy Soft Set and Its Method of Dynamic Decision Making

    OpenAIRE

    Xiaoguo Chen; Hong Du; Yue Yang

    2014-01-01

    A concept of interval-valued triangular fuzzy soft set is presented, and some operations of “AND,” “OR,” intersection, union and complement, and so forth are defined. Then some relative properties are discussed and several conclusions are drawn. A dynamic decision making model is built based on the definition of interval-valued triangular fuzzy soft set, in which period weight is determined by the exponential decay method. The arithmetic weighted average operator of interval-valued triangular...

  15. Lead toxicity, defense strategies and associated indicative biomarkers in Talinum triangulare grown hydroponically.

    Science.gov (United States)

    Kumar, Abhay; Prasad, M N V; Sytar, Oksana

    2012-11-01

    Talinum species have been used to investigate a variety of environmental problems for e.g. determination of metal pollution index and total petroleum hydrocarbons in roadside soils, stabilization and reclamation of heavy metals (HMs) in dump sites, removal of HMs from storm water-runoff and green roof leachates. Species of Talinum are popular leaf vegetables having nutrient antinutrient properties. In this study, Talinum triangulare (Jacq.) Willd (Ceylon spinach) grown hydroponically were exposed to different concentrations of lead (Pb) (0, 0.25, 0.5, 0.75, 1.0 and 1.25 mM) to investigate the biomarkers of toxicity and tolerance mechanisms. Relative water content, cell death, photosynthetic pigments, sulphoquinovosyldiacylglycerol (SQDG), anthocyanins, α-tocopherol, malondialdehyde (MDA), reactive oxygen species (ROS) glutathione (GSH and GSSG) and elemental analysis have been investigated. The results showed that Pb in roots and shoots gradually increased as the function of Pb exposure; however Pb concentration in leaves was below detectable level. Chlorophylls and SQDG contents increased at 0.25 mM of Pb treatment in comparison to control at all treated durations, thereafter decreased. Levels of carotenoid, anthocyanins, α-tocopherol, and lipid peroxidation increased in Pb treated plants compared to control. Water content, cells death and elemental analysis suggested the damage of transport system interfering with nutrient transport causing cell death. The present study also explained that Pb imposed indirect oxidative stress in leaves is characterized by decreases in GSH/GSSG ratio with increased doses of Pb treatment. Lead-induced oxidative stress was alleviated by carotenoids, anthocyanins, α-tocopherol and glutathione suggesting that these defense responses as potential biomarkers for detecting Pb toxicity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Development of Low Density CaMg-A1-Based Bulk Metallic Glasses (Preprint)

    National Research Council Canada - National Science Library

    Senkov, O. N; Scott, J. M; Miracle, D. B

    2006-01-01

    Low density Ca-Mg-Al-based bulk metallic glasses containing additionally Cu and Zn, were produced by a copper mold casting method as wedge-shaped samples with thicknesses varying from 0.5 mm to 10 rom...

  17. Low-Reynolds number compressible flow around a triangular airfoil

    Science.gov (United States)

    Munday, Phillip; Taira, Kunihiko; Suwa, Tetsuya; Numata, Daiju; Asai, Keisuke

    2013-11-01

    We report on the combined numerical and experimental effort to analyze the nonlinear aerodynamics of a triangular airfoil in low-Reynolds number compressible flow that is representative of wings on future Martian air vehicles. The flow field around this airfoil is examined for a wide range of angles of attack and Mach numbers with three-dimensional direct numerical simulations at Re = 3000 . Companion experiments are conducted in a unique Martian wind tunnel that is placed in a vacuum chamber to simulate the Martian atmosphere. Computational findings are compared with pressure sensitive paint and direct force measurements and are found to be in agreement. The separated flow from the leading edge is found to form a large leading-edge vortex that sits directly above the apex of the airfoil and provides enhanced lift at post stall angles of attack. For higher subsonic flows, the vortical structures elongate in the streamwise direction resulting in reduced lift enhancement. We also observe that the onset of spanwise instability for higher angles of attack is delayed at lower Mach numbers. Currently at Mitsubishi Heavy Industries, Ltd., Nagasaki.

  18. Triangular dislocation: an analytical, artefact-free solution

    Science.gov (United States)

    Nikkhoo, Mehdi; Walter, Thomas R.

    2015-05-01

    Displacements and stress-field changes associated with earthquakes, volcanoes, landslides and human activity are often simulated using numerical models in an attempt to understand the underlying processes and their governing physics. The application of elastic dislocation theory to these problems, however, may be biased because of numerical instabilities in the calculations. Here, we present a new method that is free of artefact singularities and numerical instabilities in analytical solutions for triangular dislocations (TDs) in both full-space and half-space. We apply the method to both the displacement and the stress fields. The entire 3-D Euclidean space {R}3 is divided into two complementary subspaces, in the sense that in each one, a particular analytical formulation fulfils the requirements for the ideal, artefact-free solution for a TD. The primary advantage of the presented method is that the development of our solutions involves neither numerical approximations nor series expansion methods. As a result, the final outputs are independent of the scale of the input parameters, including the size and position of the dislocation as well as its corresponding slip vector components. Our solutions are therefore well suited for application at various scales in geoscience, physics and engineering. We validate the solutions through comparison to other well-known analytical methods and provide the MATLAB codes.

  19. Single Null Negative Triangularity Tokamak for Power Handling

    Science.gov (United States)

    Kikuchi, Mitsuru; Medvedev, S.; Takizuka, T.; Sauter, O.; Merle, A.; Coda, S.; Chen, D.; Li, J. X.

    2017-10-01

    Power and particle control in fusion reactor is challenge and we proposed the negative triangularity tokamak (NTT) to eliminate ELM by operating L-mode edge with improved core confinement. The SN configuration has more flexibility in shaping by adopting rectangular-shaped TF coils. The limiting normalized beta is 3.56 with wall stabilization and 3.14 without wall. The vertical stability is assured under a reasonable control system. The wetted area on the divertor plates becomes wider in proportion to the larger major radius at the divertor strike points due to the NT configuration. In addition to the major-radius effect, the ``Flux Tune Expansion (FTE)'' is adopted to further reduce the heat load on the divertor plate by factor of 2.6 with a coil current 3 MA. L-mode edge also allows further increase in wetted area. The fusion power of 3 GW is deliverable only at normalized beta 2.1. Therefore this reactor may be operable stably against the serious MHD activities. The CD power for SS operation is 175 MW at Q = 17. AC operation is also possible option. A required HH factor is relatively modest H = 1.12.

  20. Magnetism of triangular nanoflakes with different compositions and edge terminations

    International Nuclear Information System (INIS)

    Zhang Shunhong; Zhou Jian; Li Xiaowei; Wang Qian

    2012-01-01

    Since the discovery of the giant magnetoresistance effect, extensive research has been devoted to finding new materials for spintronic devices. The hotly pursued nanostructure-based magnetic materials are potential candidates for such applications. Among them, graphene triangular nanoflakes (G-TNFs), due to their special magnetic configurations, can serve as building blocks for design of new C-based magnetic materials. This motivates the present study to systematically investigate how magnetism of the TNFs changes with their edge termination, composition, and atomic distribution. Using density functional theory, we show that the F-terminated G-TNFs have similar magnetic behavior to the H-terminated G-TNFs. Besides the edge terminations, partially hydrogenation of interior C atoms in the G-TNFs breaks the conjugate π orbitals and thus leads to extra net magnetic moment. The IV-group binary SiC-TNFs resemble the G-TNFs in magnetic properties, while the III–V group binary BN- and AlN-TNFs are different although they also have honeycomb structures. The different magnetic behaviors originate from the different occupations of p z atomic orbitals and the resulting change of conjugate π molecular orbitals. This study provides physical insight on tuning the magnetic behavior of TNFs through controlling their composition, size, and edge termination.

  1. Multi-domain electromagnetic absorption of triangular quantum rings.

    Science.gov (United States)

    Sitek, Anna; Thorgilsson, Gunnar; Gudmundsson, Vidar; Manolescu, Andrei

    2016-06-03

    We present a theoretical study of the unielectronic energy spectra, electron localization, and optical absorption of triangular core-shell quantum rings. We show how these properties depend on geometric details of the triangle, such as side thickness or corners' symmetry. For equilateral triangles, the lowest six energy states (including spin) are grouped in an energy shell, are localized only around corner areas, and are separated by a large energy gap from the states with higher energy which are localized on the sides of the triangle. The energy levels strongly depend on the aspect ratio of the triangle sides, i.e., thickness/length ratio, in such a way that the energy differences are not monotonous functions of this ratio. In particular, the energy gap between the group of states localized in corners and the states localized on the sides strongly decreases with increasing the side thickness, and then slightly increases for thicker samples. With increasing the thickness the low-energy shell remains distinct but the spatial distribution of these states spreads. The behavior of the energy levels and localization leads to a thickness-dependent absorption spectrum where one transition may be tuned in the THz domain and a second transition can be tuned from THz to the infrared range of electromagnetic spectrum. We show how these features may be further controlled with an external magnetic field. In this work the electron-electron Coulomb repulsion is neglected.

  2. Multi-domain electromagnetic absorption of triangular quantum rings

    Science.gov (United States)

    Sitek, Anna; Thorgilsson, Gunnar; Gudmundsson, Vidar; Manolescu, Andrei

    2016-06-01

    We present a theoretical study of the unielectronic energy spectra, electron localization, and optical absorption of triangular core-shell quantum rings. We show how these properties depend on geometric details of the triangle, such as side thickness or corners’ symmetry. For equilateral triangles, the lowest six energy states (including spin) are grouped in an energy shell, are localized only around corner areas, and are separated by a large energy gap from the states with higher energy which are localized on the sides of the triangle. The energy levels strongly depend on the aspect ratio of the triangle sides, i.e., thickness/length ratio, in such a way that the energy differences are not monotonous functions of this ratio. In particular, the energy gap between the group of states localized in corners and the states localized on the sides strongly decreases with increasing the side thickness, and then slightly increases for thicker samples. With increasing the thickness the low-energy shell remains distinct but the spatial distribution of these states spreads. The behavior of the energy levels and localization leads to a thickness-dependent absorption spectrum where one transition may be tuned in the THz domain and a second transition can be tuned from THz to the infrared range of electromagnetic spectrum. We show how these features may be further controlled with an external magnetic field. In this work the electron-electron Coulomb repulsion is neglected.

  3. Fluid Interfaces of Triangular Containers in Reduced Gravity Environments

    Science.gov (United States)

    Guttromson, Jayleen; Manning, Robert; Collicott, Steven H.

    2002-01-01

    Capillary dominated fluid dynamics will be examined in a reduced-gravity environment onboard the KC-135; in particular, the behavior of the lower portion of the meniscus in triangular tank geometries. Seven clear acrylic tanks were constructed to view seven angles of the four geometries. Silicon oil with two different viscosities, 2cs and 5cs silicon oil, were used on different days of the flight. Six tanks and one control tank are filled with a certain viscosity fluid for each flight day. During each parabola, three tanks are tested at time. The experimental tanks are exchanged between parabola sets on the KC-135. The 60deg -60deg -60deg control tank is viewed throughout the flight. To gather data, two digital video cameras and one digital still camera are placed perpendicular the viewing surface. To provide a greater contrast in the meniscus, an EL backlighting sheet was used to backlight the tanks. These images and video are then digitized, passed through NASA's mini-tracker software, and compared to a theory published my M. M. Weislogel, "Fluid Interface Phenomena in a Low-Gravity Environment: Recent Results from Drop Tower Experimentation." By focusing on a lower portion of the meniscus and using longer periods of reduced gravity, this experiment may confirm that a stationary point exists on the fluid surface. This information will enable better designing of propellant management devices, especially satellite propellant refilling and gas venting. Also, biological and material processing systems in reduced gravity environments will benefit from this data.

  4. Energy spectrums of bilayer triangular phosphorene quantum dots and antidots

    Directory of Open Access Journals (Sweden)

    Z. T. Jiang

    2017-04-01

    Full Text Available We theoretically investigate the confined states of the bilayer triangular phosphorene dots and antidots by means of the tight-binding approach. The dependence of the energy levels on the size, the type of the boundary edges, and the orientation of the dots and antidots, and the influences of the electric and magnetic fields on the energy levels, are all completely analyzed. It is found that the energy level numbers of the bilayer dots and antidots are determined by the energy levels in two layers. The external electric field can effectively tune the energy levels of the edge states in both layers to move in opposite directions. With the increase of the magnetic field, the magnetic energy levels can approach the Landau levels of the phosphorene monolayer, the phosphorene bilayer, or both, depending on the specific geometry of the monolayer-bilayer hybrid phosphorene quantum dots. This research should be helpful for the overall understanding of the electronic properties of the multilayer hybrid phosphorene nanostructures and designing the corresponding phosphorene devices.

  5. Quantum electric-dipole liquid on a triangular lattice.

    Science.gov (United States)

    Shen, Shi-Peng; Wu, Jia-Chuan; Song, Jun-Da; Sun, Xue-Feng; Yang, Yi-Feng; Chai, Yi-Sheng; Shang, Da-Shan; Wang, Shou-Guo; Scott, James F; Sun, Young

    2016-02-04

    Geometric frustration and quantum fluctuations may prohibit the formation of long-range ordering even at the lowest temperature, and therefore liquid-like ground states could be expected. A good example is the quantum spin liquid in frustrated magnets. Geometric frustration and quantum fluctuations can happen beyond magnetic systems. Here we propose that quantum electric-dipole liquids, analogues of quantum spin liquids, could emerge in frustrated dielectrics where antiferroelectrically coupled electric dipoles reside on a triangular lattice. The quantum paraelectric hexaferrite BaFe12O19 with geometric frustration represents a promising candidate for the proposed electric-dipole liquid. We present a series of experimental lines of evidence, including dielectric permittivity, heat capacity and thermal conductivity measured down to 66 mK, to reveal the existence of an unusual liquid-like quantum phase in BaFe12O19, characterized by itinerant low-energy excitations with a small gap. The possible quantum liquids of electric dipoles in frustrated dielectrics open up a fresh playground for fundamental physics.

  6. [Fluorescence Resonance Energy Transfer Detection of Cobalt Ions by Silver Triangular Nanoplates and Rhodamine 6G].

    Science.gov (United States)

    Zhang, Xiu-qing; Peng, Jun; Ling, Jian; Liu, Chao-juan; Cao, Qiu-e; Ding, Zhong-tao

    2015-04-01

    In the present paper, the authors studied fluorescence resonance energy transfer (FRET) phenomenon between silver triangular nanoplates and bovine serum albumin (BSA)/Rhodamine 6G fluorescence complex, and established a fluorescence method for the detection of cobalt ions. We found that when increasing the silver triangular nanoplates added to certain concentrations of fluorescent bovine serum albumin (BSA)/Rhodamine 6G complex, the fluorescence of Rhodamine 6G would be quenched up to 80% due to the FRET between the quencher and donor. However, in the presence of cobalt ions, the disassociation of the fluorescent complex from silver triangular nanoplates occurred and the fluorescence of the Rhodamine 6G recovered. The recovery of fluorescence intensity rate (I/I0) has a good relationship with the cobalt ion concentration (cCO2+) added. Thus, the authors developed a fluorescence method for the detection of cobalt ions based on the FRET of silver triangular nanoplates and Rhodamine 6G.

  7. A dual triangular pyramidal indentation technique based on FEA solutions for Material property evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Minsoo; Hyun, Hong Chul [Sogana Univ., Seoul (Korea, Republic of); Lee, Jin Haeng; Lee, Hyungyil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-01-15

    In this study, we suggest a method for material property evaluation by dual triangular pyramidal indenters using the reverse analysis. First, we demonstrated that load displacement curves of conical and triangular pyramidal indenters are different for the same material. For this reason, an independent research on the triangular pyramidal indenter is needed. From FE indentation analyses on various materials, we then investigated the relationships among material properties, indentation parameters and load displacement curves. From this, we established property evaluation formula using dual triangular pyramidal indenters having two different half included angles. The approach provides the values of elastic modulus, yield strength and strain hardening exponent within an average error of 3% for various materials.

  8. Facile synthesis of microporous SiO2/triangular Ag composite nanostructures for photocatalysis

    Science.gov (United States)

    Sirohi, Sidhharth; Singh, Anandpreet; Dagar, Chakit; Saini, Gajender; Pani, Balaram; Nain, Ratyakshi

    2017-11-01

    In this article, we present a novel fabrication of microporous SiO2/triangular Ag nanoparticles for dye (methylene blue) adsorption and plasmon-mediated degradation. Microporous SiO2 nanoparticles with pore size aminopropyl) trimethoxysilane) to introduce amine groups. Amine-functionalized microporous silica was used for adsorption of triangular silver (Ag) nanoparticles. The synthesized microporous SiO2 nanostructures were investigated for adsorption of different dyes including methylene blue, congo red, direct green 26 and curcumin crystalline. Amine-functionalized microporous SiO2/triangular Ag nanostructures were used for plasmon-mediated photocatalysis of methylene blue. The experimental results revealed that the large surface area of microporous silica facilitated adsorption of dye. Triangular Ag nanoparticles, due to their better charge carrier generation and enhanced surface plasmon resonance, further enhanced the photocatalysis performance.

  9. Block spins and chirality in Heisenberg model on Kagome and triangular lattices

    International Nuclear Information System (INIS)

    Subrahmanyam, V.

    1994-01-01

    The spin-1/2 Heisenberg model (HM) is investigated using a block-spin renormalization approach on Kagome and triangular lattices. In both cases, after coarse graining the triangles on original lattice and truncation of the Hilbert space to the triangular ground state subspace, HM reduces to an effective model on a triangular lattice in terms of the triangular-block degrees of freedom viz. the spin and the chirality quantum numbers. The chirality part of the effective Hamiltonian captures the essential difference between the two lattices. It is seen that simple eigenstates can be constructed for the effective model whose energies serve as upper bounds on the exact ground state energy of HM, and chiral ordered variational states have high energies compared to the other variational states. (author). 12 refs, 2 figs

  10. On the divergence of triangular and eccentric spherical sums of double Fourier series

    Energy Technology Data Exchange (ETDEWEB)

    Karagulyan, G A [Institute of Mathematics, National Academy of Sciences of Armenia, Yerevan (Armenia)

    2016-01-31

    We construct a continuous function on the torus with almost everywhere divergent triangular sums of double Fourier series. We also prove an analogous theorem for eccentric spherical sums. Bibliography: 14 titles.

  11. On the divergence of triangular and eccentric spherical sums of double Fourier series

    International Nuclear Information System (INIS)

    Karagulyan, G A

    2016-01-01

    We construct a continuous function on the torus with almost everywhere divergent triangular sums of double Fourier series. We also prove an analogous theorem for eccentric spherical sums. Bibliography: 14 titles

  12. Streamwise counter-rotating vortices generated by triangular leading edge pattern in flat plate boundary layer

    KAUST Repository

    Hasheminejad, S. M.; Mitsudharmadi, Hatsari; Winoto, S. H.; Lua, K. B.; Low, H. T.

    2016-01-01

    A series of flow visualizations were conducted to qualitatively study the development of streamwise counter-rotating vortices over a flat plate induced by triangular patterns at the leading edge of a flat plate. The experiments were carried out

  13. Diagnosing central lesions of the triangular fibrocartilage as traumatic or degenerative: a review of clinical accuracy.

    Science.gov (United States)

    Löw, S; Erne, H; Pillukat, T; Mühldorfer-Fodor, M; Unglaub, F; Spies, C K

    2017-05-01

    This study examined the reliability of surgeons' estimations as to whether central lesions of the triangular fibrocartilage complex were traumatic or degenerative. A total of 50 consecutive central triangular fibrocartilage complex lesions were independently rated by ten experienced wrist surgeons viewing high-quality arthroscopy videos. The videos were reassessed after intervals of 3 months; at the second assessment surgeons were given the patient's history, radiographs and both, each in a randomized order. Finally, the surgeons assessed the histories and radiographs without the videos. Kappa statistics revealed fair interrater agreement when the histories were added to the videos. The other four modalities demonstrated moderate agreement, with lower Kappa values for the assessment without videos. Intra-rater reliability showed fair agreement for three surgeons, moderate agreement for two surgeons and substantial agreement for five surgeons. It appears that classification of central triangular fibrocartilage complex lesions depends on the information provided upon viewing the triangular fibrocartilage complex at arthroscopy. II.

  14. Reconstruction of the lateral tibia plateau fracture with a third triangular support screw: A biomechanical study

    Directory of Open Access Journals (Sweden)

    Eduardo Moran

    2017-10-01

    Conclusion: Triangular support fixation enhanced interfragmentary stability at the ultimate stage of dynamic loading. However, the level of improvement seems to be limited and may not legitimate the intervention with an additional third screw.

  15. Recession wedge trochleoplasty as an additional procedure in the surgical treatment of patellar instability with major trochlear dysplasia: early results.

    Science.gov (United States)

    Thaunat, M; Bessiere, C; Pujol, N; Boisrenoult, P; Beaufils, P

    2011-12-01

    The importance of a dysplastic trochlea as a component of patellar instability has long been recognized. An original trochleoplasty technique consisting in retro-trochlear recession wedge osteotomy was described by Goutallier et al. The aim is not to fashion a groove but to reduce the bump without modifying patellofemoral congruence. This retrospective study reports the operative technique and short-term outcomes of a consecutive case series of 17 patients (19 knees) who underwent recession wedge trochleoplasty for patellofemoral instability associated with severe trochlear dysplasia. Other contributing factors of patellar instability were also corrected as part of the surgical procedure: tibial tuberosity transfer (n=18), MPFL reconstruction (n=8). Minimum follow-up was 12 months (mean, 34 months; range, 12 to 71 months). The trochlear prominence was reduced from a mean 4.8mm (range, 0 to 8mm) to -0.8mm (range, -8 to 6mm). Patellar tilt was reduced from a mean 14° (range, 6° to 26°) to 6° (range, -1° to 24°). Two cases showed recurrent patellofemoral instability. Mean Kujala, KOOS and IKDC score were respectively 80 (± 17), 70 (± 18) and 67 (± 17) at last follow-up. Three patients required further operations, apart from removal of metal screws: arthroscopic arthrolysis for stiffness (n=1), revision for tibial tuberosity non-union (n=1), and supratrochlear exostosectomy (n=1). Recession wedge trochleoplasty is a feasible additional procedure addressing bony trochlear abnormality in the surgical treatment of patellar instability. Our attitude is to perform it never in isolation but associated to realignment of the extensor apparatus according to the à la carte surgery concept. It seems to be effective in preventing future patellar dislocation and reducing anterior knee pain in case of painful patellofemoral instability with a major dysplastic trochlea, or in revision cases when other realignment procedures have failed. Copyright © 2011 Elsevier Masson SAS

  16. TLC scheme for numerical solution of the transport equation on equilateral triangular meshes

    International Nuclear Information System (INIS)

    Walters, W.F.

    1983-01-01

    A new triangular linear characteristic TLC scheme for numerically solving the transport equation on equilateral triangular meshes has been developed. This scheme uses the analytic solution of the transport equation in the triangle as its basis. The data on edges of the triangle are assumed linear as is the source representation. A characteristic approach or nodal approach is used to obtain the analytic solution. Test problems indicate that the new TLC is superior to the widely used DITRI scheme for accuracy

  17. Dynamic hysteresis behaviors in the kinetic Ising system on triangular lattice

    Science.gov (United States)

    Kantar, Ersin; Ertaş, Mehmet

    2018-04-01

    We studied dynamic hysteresis behaviors of the spin-1 Blume-Capel (BC) model in a triangular lattice by means of the effective-field theory (EFT) with correlations and using Glauber-type stochastic dynamics. The effects of the exchange interaction (J), crystal field (D), temperature (T) and oscillating frequency (w) on the hysteresis behaviors of the BC model in a triangular lattice are investigated in detail. Results are compared with some other dynamic studies and quantitatively good agreement is found.

  18. Unitary Root Music and Unitary Music with Real-Valued Rank Revealing Triangular Factorization

    Science.gov (United States)

    2010-06-01

    AFRL-RY-WP-TP-2010-1213 UNITARY ROOT MUSIC AND UNITARY MUSIC WITH REAL-VALUED RANK REVEALING TRIANGULAR FACTORIZATION (Postprint) Nizar...DATES COVERED (From - To) June 2010 Journal Article Postprint 08 September 2006 – 31 August 2009 4. TITLE AND SUBTITLE UNITARY ROOT MUSIC AND...UNITARY MUSIC WITH REAL-VALUED RANK REVEALING TRIANGULAR FACTORIZATION (Postprint) 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA8650-05-D-1912-0007 5c

  19. Impact of plasma triangularity and collisionality on electron heat transport in TCV L-mode plasmas

    International Nuclear Information System (INIS)

    Camenen, Y.; Pochelon, A.; Behn, R.; Bottino, A.; Bortolon, A.; Coda, S.; Karpushov, A.; Sauter, O.; Zhuang, G.

    2007-01-01

    The impact of plasma shaping on electron heat transport is investigated in TCV L-mode plasmas. The study is motivated by the observation of an increase in the energy confinement time with decreasing plasma triangularity which may not be explained by a change in the temperature gradient induced by changes in the geometry of the flux surfaces. The plasma triangularity is varied over a wide range, from positive to negative values, and various plasmas conditions are explored by changing the total electron cyclotron (EC) heating power and the plasma density. The mid-radius electron heat diffusivity is shown to significantly decrease with decreasing triangularity and, for similar plasma conditions, only half of the EC power is required at a triangularity of -0.4 compared with +0.4 to obtain the same temperature profile. Besides, the observed dependence of the electron heat diffusivity on the electron temperature, electron density and effective charge can be grouped in a unique dependence on the plasma effective collisionality. In summary, the electron heat transport level exhibits a continuous decrease with decreasing triangularity and increasing collisionality. Local gyro-fluid and global gyro-kinetic simulations predict that trapped electron modes are the most unstable modes in these EC heated plasmas with an effective collisionality ranging from 0.2 to 1. The modes stability dependence on the plasma triangularity is investigated

  20. Marginally Stable Triangular Recurrent Neural Network Architecture for Time Series Prediction.

    Science.gov (United States)

    Sivakumar, Seshadri; Sivakumar, Shyamala

    2017-09-25

    This paper introduces a discrete-time recurrent neural network architecture using triangular feedback weight matrices that allows a simplified approach to ensuring network and training stability. The triangular structure of the weight matrices is exploited to readily ensure that the eigenvalues of the feedback weight matrix represented by the block diagonal elements lie on the unit circle in the complex z-plane by updating these weights based on the differential of the angular error variable. Such placement of the eigenvalues together with the extended close interaction between state variables facilitated by the nondiagonal triangular elements, enhances the learning ability of the proposed architecture. Simulation results show that the proposed architecture is highly effective in time-series prediction tasks associated with nonlinear and chaotic dynamic systems with underlying oscillatory modes. This modular architecture with dual upper and lower triangular feedback weight matrices mimics fully recurrent network architectures, while maintaining learning stability with a simplified training process. While training, the block-diagonal weights (hence the eigenvalues) of the dual triangular matrices are constrained to the same values during weight updates aimed at minimizing the possibility of overfitting. The dual triangular architecture also exploits the benefit of parsing the input and selectively applying the parsed inputs to the two subnetworks to facilitate enhanced learning performance.

  1. Generalized monitor unit calculation for the Varian enhanced dynamic wedge field

    International Nuclear Information System (INIS)

    Liu Chihray; Kim, Siyong; Kahler, Darren L.; Palta, Jatinder R.

    2003-01-01

    The generalized monitor unit (MU) calculation equation for the Varian enhanced dynamic wedge (EDW) is derived. The assumption of this MU calculation method is that the wedge factor of the EDW at the center of the field is a function of field size, the position of the center of the field in the wedge direction, and the final position of the moving jaw. The wedge factors at the center of the field in both symmetric and asymmetric fields are examined. The difference between calculated and measured wedge factors is within 1.0%. The method developed here is easy to implement. The only datum required in addition to the standard set of conventional physical wedge implementation data is the off-axis output factor for the open field in the reference condition. The off-center point calculation is also examined. For the off-center point calculation, the dose profile in the wedge direction for the largest EDW field is used to obtain the relative off-center ratio in any smaller wedge field. The accuracy of the off-center point calculation decreases when the point of calculation is too close to the field edge

  2. Dissolved organic carbon loss from Yedoma permafrost amplified by ice wedge thaw

    International Nuclear Information System (INIS)

    Vonk, J E; Mann, P J; Spencer, R G M; Bulygina, E B; Holmes, R M; Dowdy, K L; Davydova, A; Davydov, S P; Zimov, N; Eglinton, T I

    2013-01-01

    Pleistocene Yedoma permafrost contains nearly a third of all organic matter (OM) stored in circum-arctic permafrost and is characterized by the presence of massive ice wedges. Due to its rapid formation by sediment accumulation and subsequent frozen storage, Yedoma OM is relatively well preserved and highly biologically available (biolabile) upon thaw. A better understanding of the processes regulating Yedoma degradation is important to improve estimates of the response and magnitude of permafrost carbon feedbacks to climate warming. In this study, we examine the composition of ice wedges and the influence of ice wedge thaw on the biolability of Yedoma OM. Incubation assays were used to assess OM biolability, fluorescence spectroscopy to characterize the OM composition, and potential enzyme activity rates to examine the controls and regulation of OM degradation. We show that increasing amounts of ice wedge melt water in Yedoma-leached incubations enhanced the loss of dissolved OM over time. This may be attributed to the presence of low-molecular weight compounds and low initial phenolic content in the OM of ice wedges, providing a readily available substrate that promotes the degradation of Yedoma OC. The physical vulnerability of ice wedges upon thaw (causing irreversible collapse), combined with the composition of ice wedge-engrained OM (co-metabolizing old OM), underlines the particularly strong potential of Yedoma to generate a positive feedback to climate warming relative to other forms of non-ice wedge permafrost. (letter)

  3. Comparison of dosimetric characteristics of Siemens virtual and physical wedges for ONCOR linear accelerator

    Directory of Open Access Journals (Sweden)

    Attalla Ehab

    2010-01-01

    Full Text Available Dosimetric properties of virtual wedge (VW and physical wedge (PW in 6- and 10-MV photon beams from a Siemens ONCOR linear accelerator, including wedge factors, depth doses, dose profiles, peripheral doses, are compared. While there is a great difference in absolute values of wedge factors, VW factors (VWFs and PW factors (PWFs have a similar trend as a function of field size. PWFs have stronger depth dependence than VWF due to beam hardening in PW fields. VW dose profiles in the wedge direction, in general, match very well with those of PW, except in the toe area of large wedge angles with large field sizes. Dose profiles in the nonwedge direction show a significant reduction in PW fields due to off-axis beam softening and oblique filtration. PW fields have significantly higher peripheral doses than open and VW fields. VW fields have similar surface doses as the open fields, while PW fields have lower surface doses. Surface doses for both VW and PW increase with field size and slightly with wedge angle. For VW fields with wedge angles 45° and less, the initial gap up to 3 cm is dosimetrically acceptable when compared to dose profiles of PW. VW fields in general use less monitor units than PW fields.

  4. Checks for quality control of wedge dynamics in treatment units and the planning system

    International Nuclear Information System (INIS)

    Mateos Salvador, P.; Rodriguez Lopez, B.; Font Gelabert, J.; Hernandez Rodriguez, J.; Arino Gil, A.

    2013-01-01

    The objective of this study is to verify the implementation of enhanced dynamic wedge (EDW) vary in the Eclipse planning system and the experimental determination of the parameters that define the dosimetry characteristics of enhanced dynamic wedge of our treatment units. (Author)

  5. Use of a wedge cuvette in thin layer photometry and its application to oximetry

    NARCIS (Netherlands)

    Spaan, J. A.; Garred, L. J.; van de Borne, P.

    1977-01-01

    A wedge cuvette was constructed by fixing 2 glass plates at a known angle with a spacer at one end. This resulted in a thin layer with thickness varying from 0 to 250 micrometer. By measuring the intensity of a beam of light through the thin layer as a function of distance along the wedge (and thus

  6. North Aegean core complexes, the gravity spreading of a thrust wedge

    NARCIS (Netherlands)

    Kydonakis, Konstantinos; Brun, Jean Pierre; Sokoutis, Dimitrios

    2015-01-01

    The North Aegean core complexes developed in middle Eocene soon after the end of continental block convergence and piling up of the Hellenic Thrust Wedge. They formed during back-arc extension, driven by the Hellenic slab rollback, at the back of the thrust wedge. A series of scaled laboratory

  7. Wedge gate valves selecting essentials in pipeline systems designing based on permissible operation parameters

    Science.gov (United States)

    Zakirnichnaya, M. M.; Kulsharipov, I. M.

    2017-10-01

    Wedge gate valves are widely used at the fuel and energy complex enterprises. The pipeline valves manufacturers indicate the safe operation resource according to the current regulatory and technical documentation. In this case, the resource value of the valve body strength calculation results is taken into consideration as the main structural part. However, it was determined that the wedge gate valves fail before the assigned resource due to the occurrence of conditions under which the wedge breaks in the hooks and, accordingly, the sealing integrity is not ensured. In this regard, it became necessary to assess the conditions under which the resource should be assigned not only to the valve body, but also to take into account the wedge durability. For this purpose, wedge resource calculations were made using the example of ZKL2 250-25 and ZKL2 300-25 valves using the ABAQUS software package FE-SAFE module under the technological parameters influence on the basis of their stressstrain state calculation results. Operating conditions, under which the wedge resource value is lower than the one set by the manufacturer, were determined. A technique for limiting the operating parameters for ensuring the wedge durability during the wedge gate valve assigned resource is proposed.

  8. [Treatment of triangular fibrocartilage complex tear under wrist arthroscopy].

    Science.gov (United States)

    Mi, Kun; Liu, Wu; Liu, Pengfei; Feng, Zhibin; Li, Yuwen; Hui, Guisheng

    2011-01-01

    To evaluate the treatment and effects of wrist arthroscopy in tear of triangular fibrocartilage complex (TFCC). Between January 2006 and December 2008, 16 patients with tear of TFCC were treated. Of 16 patients, 11 were male and 5 were female with an average age of 32.5 years (range, 25-51 years). Injury was caused by sprain in 12 cases, and by falling in 4 cases. The locations were the left side in 10 cases and the right side in 6 cases. The mean injury duration was 3 months to 6 years and 2 months. The main clinical symptoms included wrist powerlessness and ulnar-sided wrist pain which was aggravated with clench fist and lifting heavy things. The results of the ulnar-sided wrist stress test were positive in 14 cases and negative in 2 cases. The preoperative values of wrist range of motion (ROM) were (45.58 +/- 5.18) degrees at volar flexion, (41.22 +/- 3.83) degrees at dorsal extension, (17.82 +/- 2.48) degrees at radial deviation, (21.35 +/- 4.61) degrees at ulnar deviation, (69.85 +/- 8.36) degrees at pronation, and (70.13 +/- 6.34) degrees at supination. According to Palmer standard, 10 cases of IA were treated with debridement; 3 cases of IB with suture and 1 of them failed and was partially excised; 2 cases of IC with debridement on triangular fibrocartilage disc, ulnolunate ligament, and ulnotriguetrum ligament; and 1 case of ID with trimming plastic operation. All incisions healed by first intention, and no complications of joint infection or neurovascular injury was found. All patients were followed up 14-38 months (mean, 18.5 months). Fifteen patients were restored to normal life and work without ulnar-sided wrist pain. One patient had no pain, but he had wrist powerless. The values of ROM at last follow-up were (50.16 +/- 6.21) degrees at volar flexion, (45.37 +/- 4.65) degrees at dorsal extension, (18.95 +/- 3.56) degrees at radial deviation, (26.28 +/- 5.09) degrees at ulnar deviation, (78.87 +/- 7.69) degrees at pronation, and (76.46 +/- 8

  9. TINITALY/01: a new Triangular Irregular Network of Italy

    Directory of Open Access Journals (Sweden)

    M. T. Pareschi

    2007-06-01

    Full Text Available A new Digital Elevation Model (DEM of the natural landforms of Italy is presented. A methodology is discussed to build a DEM over wide areas where elevation data from non-homogeneous (in density and accuracy input sources are available. The input elevation data include contour lines and spot heights derived from the Italian Regional topographic maps, satellite-based global positioning system points, ground based and radar altimetry data. Owing to the great heterogeneity of the input data density, the DEM format that better preserves the original accuracy is a Triangular Irregular Network (TIN. A Delaunay-based TIN structure is improved by using the DEST algorithm that enhances input data by evaluating inferred break-lines. Accordingly to this approach, biased distributions in slopes and elevations are absent. To prevent discontinuities at the boundary between regions characterized by data with different resolution a cubic Hermite blending weight S-shaped function is adopted. The TIN of Italy consists of 1.39×109 triangles. The average triangle area ranges from 12 to about 13000 m2 accordingly to different morphologies and different sources. About 50% of the model has a local average triangle area <500 m2. The vertical accuracy of the obtained DEM is evaluated by more than 200000 sparse control points. The overall Root Mean Square Error (RMSE is less than 3.5 m. The obtained national-scale DEM constitutes an useful support to carry out accurate geomorphological and geological investigations over large areas. The problem of choosing the best step size in deriving a grid from a TIN is then discussed and a method to quantify the loss of vertical information is presented as a function of the grid step. Some examples of DEM application are outlined. Under request, an high resolution stereo image database of the whole Italian territory (derived from the presented DEM is available to browse via internet.

  10. Triangular fibrocartilage lesions: comparison STIR sequence versus arthroscopy findings

    International Nuclear Information System (INIS)

    Wang Zhi; Meng; Xianghong; Wang Linsen; Suo Yongmei

    2013-01-01

    Objective: To explore the diagnostic value of short TI inversion recovery (STIR) sequence in evaluating triangular fibrocartilage (TFC) lesions, and to compare the findings with the arthroscopy findings. Materials and Methods: Wrist joint MR examination using STIR sequence and arthroscopy were performed in 56 patients with TFC lesions. The parameters of STIR sequence were: TR: 1164 ms, TE: 16 ms, and TI: 90 ms. The sensibility, specificity, positive predictive value, negative predictive value, and accuracy in the diagnosis of TFC lesions with STIR sequence were calculated, using arthroscopy as the standard. Results: (1) STIR manifested 10 patients with normal TFC; 6 with small edema or mucous degeneration in the body portion but not involving joint surface edge; 6 with horizontal avulsion in the body portion, but not involving joint surface edge; 6 with avulsion involving joint surface edge; 11 with perforation in central portion; 6 with avulsion in radial attached end; 5 with avulsion in ulnar attached end; 3 with avulsion in both radial and ulnar attached ends; 3 with irregular shape and thin on the whole TFC. (2) Arthroscopy manifested 21 patients with normal TFC; 8 with avulsion involving joint surface edge; 10 with perforation in central portion; 7 with avulsion in radial attached end; 5 with avulsion in ulnar attached end; 2 with avulsion in both radial and ulnar attached ends; 3 with irregular shape on the whole TFC. Using STIR sequence, the sensibility, specificity, positive predictive value, negative predictive value. and accuracy were 85.7%, 23.8%, 65.2%, 50%, and 62.5%, respectively, in detection of TFC lesions, with arthroscopy as the standard. Conclusion: STIR sequence has high diagnostic value in detection of TFC lesions. (authors)

  11. Psyplot: Visualizing rectangular and triangular Climate Model Data with Python

    Science.gov (United States)

    Sommer, Philipp

    2016-04-01

    The development and use of climate models often requires the visualization of geo-referenced data. Creating visualizations should be fast, attractive, flexible, easily applicable and easily reproducible. There is a wide range of software tools available for visualizing raster data, but they often are inaccessible to many users (e.g. because they are difficult to use in a script or have low flexibility). In order to facilitate easy visualization of geo-referenced data, we developed a new framework called "psyplot," which can aid earth system scientists with their daily work. It is purely written in the programming language Python and primarily built upon the python packages matplotlib, cartopy and xray. The package can visualize data stored on the hard disk (e.g. NetCDF, GeoTIFF, any other file format supported by the xray package), or directly from the memory or Climate Data Operators (CDOs). Furthermore, data can be visualized on a rectangular grid (following or not following the CF Conventions) and on a triangular grid (following the CF or UGRID Conventions). Psyplot visualizes 2D scalar and vector fields, enabling the user to easily manage and format multiple plots at the same time, and to export the plots into all common picture formats and movies covered by the matplotlib package. The package can currently be used in an interactive python session or in python scripts, and will soon be developed for use with a graphical user interface (GUI). Finally, the psyplot framework enables flexible configuration, allows easy integration into other scripts that uses matplotlib, and provides a flexible foundation for further development.

  12. Pilot production of the wedge filter for the TBI (total body irradiation)

    International Nuclear Information System (INIS)

    Ikezaki, Hiromi; Ikeda, Ikuo; Maruyama, Yasushi; Nako, Yasunobu; Tonari, Ayako; Kusuda, Junko; Takayama, Makoto

    2007-01-01

    Total body irradiation (TBI) is performed by various methods, such as a long SSD method and a translational couch method. For patient safety in carrying out TBI, the patient should be placed on the supine position and prone position near the floor. TBI is performed from 2 opposite ports (AP/PA) with a linear accelerator (10 MV X-ray). We experimented with a wedge filter for TBI created by us, which makes dose distribution to a floor uniform. The wedge filter, made of iron alloy, was attached to the linear accelerator. In designing the wedge filter, thickness of the lead-made wedge filter can be calculated numerically from the ratio of linear attenuation coefficient of iron alloy and lead. In measuring the dose profile for a phantom of 20 cm thick, dose homogeneity less than 10% was proved by the wedge filter for TBI. (author)

  13. Seismic characterization of a `compound tectonic wedge` beneath the Rocky Mountain foreland basin, Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, D. C.; Sukaramongkol, C.; Spratt, D. A. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

    1996-06-01

    The detailed internal geometry of a `compound tectonic wedge` beneath an eastward-dipping homocline in the Sundre area of southern Alberta was described. Data for the description was obtained by interpreting reflection seismic data. The wedge has been driven into the foreland succession beneath the gently dipping upper detachment which occurs within coal horizons of the Upper Brazeau Group. Shape of the upper detachment near its toe indicates that rocks in its hanging wall were decoupled from strain associated with forward emplacement of the wedge. Folding of the upper detachment occurs in the hinterland region of the wedge, with a new upper detachment developing above the fold. Emplacement of the wedge is suspected to be the result of excess pore fluid pressure, although proof of this happening awaits quantification of the mechanical model. 25 refs., 8 figs.

  14. Magnetization study of interlayer exchange in semiconductor EuS-PbS ferromagnetic wedge multilayers

    International Nuclear Information System (INIS)

    Kowalczyk, L.; Osinniy, V.; Chernyshova, M.; Dziawa, P.; Boratynski, A.; Story, T.; Smits, C.J.P.; Swagten, H.J.M.; Sipatov, A.Yu.; Volobuev, V.V.

    2006-01-01

    Interlayer coupling was experimentally studied in semiconductor EuS-PbS ferromagnetic superlattice wedge structures grown on KCl (0 0 1) substrates with the wedges covering the semiconductor nonmagnetic PbS spacer layer thickness from 0.3 to 6 nm. Structural parameters of the wedges were examined by X-ray diffraction analysis of EuS-PbS superlattice period. Measurements of magnetic hysteresis loops of EuS-PbS structures were performed by both SQUID (for small terminal parts of the wedge) and MOKE (magneto-optical analysis along the wedge) magnetometry. A strong decrease of magnetic remanence and an increase of saturation field observed for EuS-PbS structures with the PbS spacer thickness decreasing below about 1.5 nm is discussed in terms of the influence of antiferromagnetic interlayer coupling

  15. Isolating active orogenic wedge deformation in the southern Subandes of Bolivia

    Science.gov (United States)

    Weiss, Jonathan R.; Brooks, Benjamin A.; Foster, James H.; Bevis, Michael; Echalar, Arturo; Caccamise, Dana; Heck, Jacob; Kendrick, Eric; Ahlgren, Kevin; Raleigh, David; Smalley, Robert; Vergani, Gustavo

    2016-08-01

    A new GPS-derived surface velocity field for the central Andean backarc permits an assessment of orogenic wedge deformation across the southern Subandes of Bolivia, where recent studies suggest that great earthquakes (>Mw 8) are possible. We find that the backarc is not isolated from the main plate boundary seismic cycle. Rather, signals from subduction zone earthquakes contaminate the velocity field at distances greater than 800 km from the Chile trench. Two new wedge-crossing velocity profiles, corrected for seasonal and earthquake affects, reveal distinct regions that reflect (1) locking of the main plate boundary across the high Andes, (2) the location of and loading rate at the back of orogenic wedge, and (3) an east flank velocity gradient indicative of décollement locking beneath the Subandes. Modeling of the Subandean portions of the profiles indicates along-strike variations in the décollement locked width (WL) and wedge loading rate; the northern wedge décollement has a WL of ~100 km while accumulating slip at a rate of ~14 mm/yr, whereas the southern wedge has a WL of ~61 km and a slip rate of ~7 mm/yr. When compared to Quaternary estimates of geologic shortening and evidence for Holocene internal wedge deformation, the new GPS-derived wedge loading rates may indicate that the southern wedge is experiencing a phase of thickening via reactivation of preexisting internal structures. In contrast, we suspect that the northern wedge is undergoing an accretion or widening phase primarily via slip on relatively young thrust-front faults.

  16. Two-dimensional electronic spectroscopy with birefringent wedges

    Energy Technology Data Exchange (ETDEWEB)

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-12-15

    We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

  17. Computer dosimetry for flattened and wedged fast-neutron beams

    International Nuclear Information System (INIS)

    Hogstrom, K.R.; Smith, A.R.; Almond, P.R.; Otte, V.A.; Smathers, J.B.

    1976-01-01

    Beam flattening by the use of polyethylene filters has been developed for the 50-MeV d→Be fast-neutron therapy beam at the Texas AandM Variable-Energy Cyclotron (TAMVEC) as a result of the need for a more uniform dose distribution at depth within the patient. A computer algorithm has been developed that allows the use of a modified decrement line method to calculate dose distributions; standard decrement line methods do not apply because of off-axis peaking. The dose distributions for measured flattened beams are transformed into distributions that are physically equivalent to an unflattened distribution. In the transformed space, standard decrement line theory yields a distribution for any field size which, by applying the inverse transformation, generates the flattened dose distribution, including the off-axis peaking. A semiempirical model has been constructed that allows the calculation of dose distributions for wedged beams from open-beam data

  18. Metamaterials based on wedge-shaped electrodynamic structures

    Directory of Open Access Journals (Sweden)

    Mitrokhin Vladimir

    2017-01-01

    Full Text Available The paper studies a possibility of simulation of artificial composite media with negative values of the real part of the equivalent dielectric (magnetic permittivity, by the use of segments of hollow composite waveguides with cylindrical guided waves in evanescent mode. Reactive evanescent fields of wedge-shaped waveguide eigenmodes are formed in the evanescent region before the critical section of the waveguide which separates the quasistatic field region from the distributing field of the evanescent waveguide mode. The possibility of simulation is determined by the equivalence of dispersion equation of the eigenmode propagation constant and the dispersion equation for the electric (magnetic permittivity of plasma-like medium if cut-off frequency and electric (magnetic plasma frequency of the medium are equal.

  19. Lower limit of strength wedge-type anchor bolts

    International Nuclear Information System (INIS)

    Arnedo Pena, A.; Frances Urmeneta, M.

    1998-01-01

    Simple expansion bolts, with a split expansion ring and a threaded bolt with an integral cone expander, called wedge type, are very used in securing and anchoring structures. The anchorage is obtained by a mechanism of torque-controlled expansion. Although less resistant than other types, its easy installation and low cost make them very competitive in light structures. In this paper, the minimum capacity values are analysed, when they are used to anchor safety-related equipment in NPP. The EPRI criteria developed in response to USI A-46 are applied and complemented by the new CEB Anchorage Design Guide. The results are compared with the information from european manufactures, adopting different safety factors for cracked and non-cracked concrete. With adequate control and inspection measures, including areas of noticeable cracking of concrete. minimum values for equipment can be obtained satisfying the strictest seismic validation requirements. (Author) 5 refs

  20. Dosimetric parameters of enhanced dynamic wedge for treatment planning and verification

    International Nuclear Information System (INIS)

    Leavitt, Dennis D.; Lee, Wing Lok; Gaffney, David K.

    1996-01-01

    Purpose/Objective: Enhanced Dynamic Wedge (EDW) is an intensity-modulated radiotherapy technique in which one collimating jaw sweeps across the field to define a desired wedge dose distribution while dose rate is modified according to jaw position. This tool enables discrete or continuous wedge angles from zero to sixty degrees for field widths from three cm to 30 cm in the direction of the wedge, and up to 40 cm perpendicular to the wedge direction. Additionally, asymmetric wedge fields not centered on the line through isocenter can be created for applications such as tangential breast irradiation. The unique range of field shapes and wedge angles introduce a new set of dosimetric challenges to be resolved before routine clinical use of EDW, and especially require that a simple set of independent dose calculation and verification techniques be developed to check computerized treatment planning results. Using terminology in common use in treatment planning, this work defines the effective wedge factor vs. field width and wedge angle, evaluates the depth dose vs. open field values, defines primary intensity functions from which specific dynamic wedges can be calculated in treatment planning systems, and describes the technique for independent calculation of Monitor Units for EDW fields. Materials and Methods: Using 6- and 18-MV beams from a CI2100C, EDW beam profiles were measured in water phantom for depths from near-surface to 30 cm for the full range of field widths and wedge angles using a linear detector array of 25 energy-compensated diodes. Asymmetric wedge field profiles were likewise measured. Depth doses were measured in water phantom using an ionization chamber sequentially positioned to depths of 30 cm. Effective wedge factors for the full range of field widths and wedge angles were measured using an ionization chamber in water-equivalent plastic at a depth of 10 cm on central axis. Dose profiles were calculated by computer as the summation of a series

  1. The triangular density to approximate the normal density: decision rules-of-thumb

    International Nuclear Information System (INIS)

    Scherer, William T.; Pomroy, Thomas A.; Fuller, Douglas N.

    2003-01-01

    In this paper we explore the approximation of the normal density function with the triangular density function, a density function that has extensive use in risk analysis. Such an approximation generates a simple piecewise-linear density function and a piecewise-quadratic distribution function that can be easily manipulated mathematically and that produces surprisingly accurate performance under many instances. This mathematical tractability proves useful when it enables closed-form solutions not otherwise possible, as with problems involving the embedded use of the normal density. For benchmarking purposes we compare the basic triangular approximation with two flared triangular distributions and with two simple uniform approximations; however, throughout the paper our focus is on using the triangular density to approximate the normal for reasons of parsimony. We also investigate the logical extensions of using a non-symmetric triangular density to approximate a lognormal density. Several issues associated with using a triangular density as a substitute for the normal and lognormal densities are discussed, and we explore the resulting numerical approximation errors for the normal case. Finally, we present several examples that highlight simple decision rules-of-thumb that the use of the approximation generates. Such rules-of-thumb, which are useful in risk and reliability analysis and general business analysis, can be difficult or impossible to extract without the use of approximations. These examples include uses of the approximation in generating random deviates, uses in mixture models for risk analysis, and an illustrative decision analysis problem. It is our belief that this exploratory look at the triangular approximation to the normal will provoke other practitioners to explore its possible use in various domains and applications

  2. A novel numerical framework for self-similarity in plasticity: Wedge indentation in single crystals

    Science.gov (United States)

    Juul, K. J.; Niordson, C. F.; Nielsen, K. L.; Kysar, J. W.

    2018-03-01

    A novel numerical framework for analyzing self-similar problems in plasticity is developed and demonstrated. Self-similar problems of this kind include processes such as stationary cracks, void growth, indentation etc. The proposed technique offers a simple and efficient method for handling this class of complex problems by avoiding issues related to traditional Lagrangian procedures. Moreover, the proposed technique allows for focusing the mesh in the region of interest. In the present paper, the technique is exploited to analyze the well-known wedge indentation problem of an elastic-viscoplastic single crystal. However, the framework may be readily adapted to any constitutive law of interest. The main focus herein is the development of the self-similar framework, while the indentation study serves primarily as verification of the technique by comparing to existing numerical and analytical studies. In this study, the three most common metal crystal structures will be investigated, namely the face-centered cubic (FCC), body-centered cubic (BCC), and hexagonal close packed (HCP) crystal structures, where the stress and slip rate fields around the moving contact point singularity are presented.

  3. [Classification and MR imaging of triangular fibrocartilage complex lesions].

    Science.gov (United States)

    Zhan, H L; Liu, Y; Bai, R J; Qian, Z H; Ye, W; Li, Y X; Wu, B D

    2016-06-07

    To explore the MRI characteristics of injuries of triangular fibrocartilage complex (TFCC), and provide imaging basis for the early diagnosis and treatment of the injuries. A total of 10 healthy volunteers without wrist injuries and 200 patients from Beijing Jishuitan Hospital who complained ulnar-sided wrist pain and were highly suspected as the injury of TFCC underwent the wrist magnetic resonance examination. All subjects were in a prone position and underwent examination on coronal T1WI scan and PD-FS on 3 planes respectively. Then the MRI characteristics of 3 healthy volunteers and 67 patients with TFCC injuries that confirmed by operation were analyzed. According to the comparative analysis of normal anatomy and Palmer classification, the injuries were classified and MRI features of different types of injuries were analyzed. At last, imaging findings were compared with surgical results. Three healthy volunteers without injuries showed mainly in low signal intensity on T1WI and PD-FS images. According to Palmer classification, there were 52 traumatic injuries (ⅠA 9, ⅠB 25, ⅠC 3, ⅠD 13, In addition, 1 has central perforation and ulnar avulsion and 1 has ulnar and radial injuries simultaneously) and 15 degenerative injuries (ⅡA 5, ⅡB 1, ⅡC 2 , ⅡD 1 , ⅡE 6) among 67 patients. The central perforation mainly demonstrated as linear high signal perpendicular to the disk, and run in a sagittal line. The ulnar, distal, and radial avulsion mainly showed the injuries were irregular, the structures were ambiguous, and there was high signal intensity in the injured structures on PD-FS. Degenerative injuries demonstrated the irregularity of TFC and heterogeneous signals on PD-FS. There were mixed intermediate-high signals and changes in the articular cartilage of lunate and ulna, high signal in the lunotriquetral ligament and ulnocarpal or radioulnar arthritis. MRI can demonstrate the anatomy of TFCC accurately, evaluate and make the general classification

  4. Late Holocene ice wedges near Fairbanks, Alaska, USA: Environmental setting and history of growth

    Science.gov (United States)

    Hamilton, T.D.; Ager, T.A.; Robinson, S.W.

    1983-01-01

    Test trenches excavated into muskeg near Fairbanks in 1969 exposed a polygonal network of active ice wedges. The wedges occur in peat that has accumulated since about 3500 yr BP and have grown episodically as the permafrost table fluctuated in response to fires, other local site conditions and perhaps regional climatic changes. Radiocarbon dates suggest one or two episodes of ice-wedge growth between about 3500 and 2000 yr BP as woody peat accumulated at the site. Subsequent wedge truncation evidently followed a fire that charred the peat. Younger peat exhibits facies changes between sedge-rich components that filled troughs over the ice wedges and woody bryophytic deposits that formed beyond the troughs. A final episode of wedge development took place within the past few hundred years. Pollen data from the site indicate that boreal forest was present throughout the past 6000 yr, but that it underwent a gradual transition from a predominantly deciduous to a spruce-dominated assemblage. This change may reflect either local site conditions or a more general climatic shift to cooler, moister summers in late Holocene time. The history of ice-wedge growth shows that wedges can form and grow to more than 1 m apparent width under mean annual temperatures that probably are close to those of the Fairbanks area today (-3.5°C) and under vegetation cover similar to that of the interior Alaskan boreal forest. The commonly held belief that ice wedges develop only below mean annual air temperatures of -6 to -8°C in the zone of continuous permafrost is invalid.

  5. Two brittle ductile transitions in subduction wedges, as revealed by topography

    Science.gov (United States)

    Thissen, C.; Brandon, M. T.

    2013-12-01

    Subduction wedges contain two brittle ductile transitions. One transition occurs within the wedge interior, and a second transition occurs along the decollement. The decollement typically has faster strain rates, which suggests that the brittle ductile transition along the decollement will be more rearward (deeper) than the transition within the interior. However, the presence of distinct rheologies or other factors such as pore fluid pressure along the decollement may reverse the order of the brittle-ductile transitions. We adopt a solution by Williams et al., (1994) to invert for these brittle ductile transitions using the wedge surface topography. At present, this model does not include an s point or sediment loading atop the wedge. The Hellenic wedge, however, as exposed in Crete presents an ideal setting to test these ideas. We find that the broad high of the Mediterranean ridge represents the coulomb frictional part of the Hellenic wedge. The rollover in topography north of the ridge results from curvature of the down going plate, creating a negative alpha depression in the vicinity of the Strabo, Pliny, and Ionian 'troughs' south of Crete. A steep topographic rise out of these troughs and subsequent flattening reflects the brittle ductile transition at depth in both the decollement and the wedge interior. Crete exposes the high-pressure viscous core of the wedge, and pressure solution textures provide additional evidence for viscous deformation in the rearward part of the wedge. The location of the decollement brittle ductile transition has been previously poorly constrained, and Crete has never experienced a subduction zone earthquake in recorded history. Williams, C. A., et al., (1994). Effect of the brittle ductile transition on the topography of compressive mountain belts on Earth and Venus. Journal of Geophysical Research Solid Earth

  6. Observations of Lower Mississippi River Estuarine Dynamics: Effects of the Salt Wedge on Sediment Deposition

    Science.gov (United States)

    Ramirez, M. T.; Allison, M. A.

    2017-12-01

    The lowermost Mississippi River is subject to salt-wedge estuarine conditions during seasonally low flow, when seaward flow is unable to overcome density stratification. Previous studies in the Mississippi River salt wedge have shown the deposition of a fine sediment layer accumulating several mm/day beneath the reach where the salt wedge is present. Field studies were conducted during low flow in 2012-2015 utilizing ADCP, CTD, LISST, and physical samples to observe the physics of the salt wedge reach and to calculate rates and character of sediment trapping beneath the salt wedge. The field observations were summarized using a two-layer box-model representation of the reach to calculate water and sediment budgets entering, exiting, and stored within the reach. The salt wedge reach was found to be net depositional at rates up to 1.8 mm/day. The mechanism for transferring sediment mass from the downstream-flowing fluvial layer to the upstream-flowing marine layer appears to be flocculation, evidenced in LISST data by a spike in sediment particle diameters at the halocline. Applying reach-averaged rates of sediment trapping to a time-integrated model of salt-wedge position, we calculated annual totals ranging from 0.025 to 2.2 million tons of sediment deposited beneath the salt wedge, depending on salt-wedge persistence and upstream extent. Most years this seasonal deposit is remobilized during spring flood following the low-flow estuarine season, which may affect the timing of sediment delivery to the Gulf of Mexico, as well as particulate organic carbon, whose transport trajectory mirrors that of mineral sediment. These results are also relevant to ongoing dredging efforts necessary to maintain the economically-important navigation pathway through the lower Mississippi River, as well as planned efforts to use Mississippi River sedimentary resources to build land in the degrading Louisiana deltaic coast.

  7. Utilization of an electronic portal imaging device for measurement of dynamic wedge data

    International Nuclear Information System (INIS)

    Elder, Eric S.; Miner, Marc S.; Butker, Elizabeth K.; Sutton, Danny S.; Davis, Lawrence W.

    1996-01-01

    Purpose/Objective: Due to the motion of the collimator during dynamic wedge treatments, the conventional method of collecting comprehensive wedge data with a water tank and a scanning ionization chamber is obsolete. It is the objective of this work to demonstrate the use of an electronic portal imaging device (EPID) and software to accomplish this task. Materials and Methods: A Varian Clinac[reg] 2300 C/D, equipped with a PortalVision TM EPID and Dosimetry Research Mode experimental software, was used to produce the radiation field. The Dosimetry Research Mode experimental software allows for a band of 10 of 256 high voltage electrodes to be continuously read and averaged by the 256 electrometer electrodes. The file that is produced contains data relating to the integrated ionization at each of the 256 points, essentially the cross plane beam profile. Software was developed using Microsoft C ++ to reformat the data for import into a Microsoft Excel spreadsheet allowing for easy mathematical manipulation and graphical display. Beam profiles were measured by the EPID with a 100 cm TSD for various field sizes. Each field size was measured open, steel wedged, and dynamically wedged. Scanning ionization chamber measurements performed in a water tank were compared to the open and steel wedged fields. Ionization chamber measurements taken in a water tank were compared with the dynamically wedged measurements. For the EPID measurements the depth was varied using Gammex RMI Solid Water TM placed directly above the EPID sensitive volume. Bolus material was placed between the Solid Water TM and the EPID to avoid an air gap. Results: Comparison of EPID measurements with those from an ion chamber in a water tank showed a discrepancy of ∼5%. Scans were successfully obtained for open, steel wedged and dynamically wedged beams. Software has been developed to allow for easy graphical display of beam profiles. Conclusions: Measurement of dynamic wedge data proves to be easily

  8. A framework for dense triangular matrix kernels on various manycore architectures

    KAUST Repository

    Charara, Ali

    2017-06-06

    We present a new high-performance framework for dense triangular Basic Linear Algebra Subroutines (BLAS) kernels, ie, triangular matrix-matrix multiplication (TRMM) and triangular solve (TRSM), on various manycore architectures. This is an extension of a previous work on a single GPU by the same authors, presented at the EuroPar\\'16 conference, in which we demonstrated the effectiveness of recursive formulations in enhancing the performance of these kernels. In this paper, the performance of triangular BLAS kernels on a single GPU is further enhanced by implementing customized in-place CUDA kernels for TRMM and TRSM, which are called at the bottom of the recursion. In addition, a multi-GPU implementation of TRMM and TRSM is proposed and we show an almost linear performance scaling, as the number of GPUs increases. Finally, the algorithmic recursive formulation of these triangular BLAS kernels is in fact oblivious to the targeted hardware architecture. We, therefore, port these recursive kernels to homogeneous x86 hardware architectures by relying on the vendor optimized BLAS implementations. Results reported on various hardware architectures highlight a significant performance improvement against state-of-the-art implementations. These new kernels are freely available in the KAUST BLAS (KBLAS) open-source library at https://github.com/ecrc/kblas.

  9. A framework for dense triangular matrix kernels on various manycore architectures

    KAUST Repository

    Charara, Ali; Keyes, David E.; Ltaief, Hatem

    2017-01-01

    We present a new high-performance framework for dense triangular Basic Linear Algebra Subroutines (BLAS) kernels, ie, triangular matrix-matrix multiplication (TRMM) and triangular solve (TRSM), on various manycore architectures. This is an extension of a previous work on a single GPU by the same authors, presented at the EuroPar'16 conference, in which we demonstrated the effectiveness of recursive formulations in enhancing the performance of these kernels. In this paper, the performance of triangular BLAS kernels on a single GPU is further enhanced by implementing customized in-place CUDA kernels for TRMM and TRSM, which are called at the bottom of the recursion. In addition, a multi-GPU implementation of TRMM and TRSM is proposed and we show an almost linear performance scaling, as the number of GPUs increases. Finally, the algorithmic recursive formulation of these triangular BLAS kernels is in fact oblivious to the targeted hardware architecture. We, therefore, port these recursive kernels to homogeneous x86 hardware architectures by relying on the vendor optimized BLAS implementations. Results reported on various hardware architectures highlight a significant performance improvement against state-of-the-art implementations. These new kernels are freely available in the KAUST BLAS (KBLAS) open-source library at https://github.com/ecrc/kblas.

  10. The Interval-Valued Triangular Fuzzy Soft Set and Its Method of Dynamic Decision Making

    Directory of Open Access Journals (Sweden)

    Xiaoguo Chen

    2014-01-01

    Full Text Available A concept of interval-valued triangular fuzzy soft set is presented, and some operations of “AND,” “OR,” intersection, union and complement, and so forth are defined. Then some relative properties are discussed and several conclusions are drawn. A dynamic decision making model is built based on the definition of interval-valued triangular fuzzy soft set, in which period weight is determined by the exponential decay method. The arithmetic weighted average operator of interval-valued triangular fuzzy soft set is given by the aggregating thought, thereby aggregating interval-valued triangular fuzzy soft sets of different time-series into a collective interval-valued triangular fuzzy soft set. The formulas of selection and decision values of different objects are given; therefore the optimal decision making is achieved according to the decision values. Finally, the steps of this method are concluded, and one example is given to explain the application of the method.

  11. A theoretical study of resonant tunneling characteristics in triangular double-barrier diodes

    International Nuclear Information System (INIS)

    Wang Hongmei; Xu Huaizhe; Zhang Yafei

    2006-01-01

    Resonant tunneling characteristics of triangular double-barrier diodes have been investigated systematically in this Letter, using Airy function approach to solve time-independent Schroedinger function in triangular double-barrier structures. Originally, the exact analytic expressions of quasi-bound levels and quasi-level lifetime in symmetrical triangular double-barrier structures have been derived within the effective-mass approximation as a function of structure parameters including well width, slope width and barrier height. Based on our derived analytic expressions, numerical results show that quasi-bound levels and quasi-level lifetime vary nearly linearly with the structure parameters except that the second quasi-level lifetime changes parabolically with slope width. Furthermore, according to our improved transmission coefficient of triangular double-barrier structures under external electric field, the current densities of triangular double-barrier diodes with different slope width at 0 K have been calculated numerically. The results show that the N-shaped negative differential resistance behaviors have been observed in current-voltage characteristics and current-voltage characteristics depend on the slope width

  12. Optimum thermal design of microchannel heat sink with triangular reentrant cavities

    International Nuclear Information System (INIS)

    Xia Guodong; Chai Lei; Wang Haiyan; Zhou Mingzheng; Cui Zhenzhen

    2011-01-01

    The effect of geometric parameters on water flow and heat transfer characteristics in microchannel heat sink with triangular reentrant cavities is numerically investigated. A three-dimensional laminar flow model, consisting of Navier-Stokes equations and energy conservation equation, with the conjugate heat transfer between the silicon base and water taken into consideration is solved numerically. In order to find the optimum geometric parameters, four variables, representing the distance and geometry of the triangular reentrant cavity, are designed. It is found that the vortices in the triangular reentrant cavities lead to chaotic advection and can greatly enhance the convective fluid mixing. The thermal and hydraulic boundary layers are interrupted and the repeated developing flow enhances heat transfer in the constant cross-section segment. Furthermore, the effects of the four design variables on heat transfer augmentation and pressure drop penalty are investigated depending on different Reynolds numbers by using the simulated annealing method. Based on the thermal enhancement factor performance maps, the optimal geometric parameters are obtained in principle. - Research highlights: → The microchannels with different triangular reentrant cavities are numerically investigated. → The heat transfer enhancement attributes to fluid mixing and redeveloped thermal boundary layers. → The optimal distance and geometry of the triangular reentrant cavity are obtained in principle.

  13. Hesitant triangular fuzzy information aggregation operators based on Bonferroni means and their application to multiple attribute decision making.

    Science.gov (United States)

    Wang, Chunyong; Li, Qingguo; Zhou, Xiaoqiang; Yang, Tian

    2014-01-01

    We investigate the multiple attribute decision-making (MADM) problems with hesitant triangular fuzzy information. Firstly, definition and some operational laws of hesitant triangular fuzzy elements are introduced. Then, we develop some hesitant triangular fuzzy aggregation operators based on Bonferroni means and discuss their basic properties. Some existing operators can be viewed as their special cases. Next, we apply the proposed operators to deal with multiple attribute decision-making problems under hesitant triangular fuzzy environment. Finally, an illustrative example is given to show the developed method and demonstrate its practicality and effectiveness.

  14. Variations in depth-dose data between open and wedge fields for 4-MV x-rays

    International Nuclear Information System (INIS)

    Sewchand, W.; Khan, F.M.; Williamson, J.

    1978-01-01

    Central-axis depth-dose data for 4-MV x rays, including tissue-maximum ratios, were measured for wedge fields. Comparison with corresponding open-field data revealed differences in magnitude which increased with depth, field size, and wedge thickness. However, phantom scatter correction factors for the wedge fields differed less than 1% from corresponding open-field factors. The differences in central-axis percent depth doses between the two types of fields indicate beam hardening by the wedge filter. This study also implies that the derivation of tissue-maximum ratios from central-axis percent depth is as valid for wedge as for open fields

  15. The effect of shoe design and lateral wedging on knee loading

    DEFF Research Database (Denmark)

    Mølgaard, Carsten; Kersting, Uwe G.

    The increasing number of patients with developing osteoarthritis is accompanied by a growing scientific interest in non-operative early treatment strategies. It is generally believed that laterally wedged insoles can change the distribution of the knee loading, but the importance of footwear design...... shoe were revealed. Conclusion: Lateral wedging is effective regardless of shoe design. Differences between the four neutral walking conditions underline the importance of footwear choice in individuals. It is safe to apply lateral wedges without jeopardizing muscular control during walking regardless...

  16. Physical optics-based diffraction coefficient for a wedge with different face impedances.

    Science.gov (United States)

    Umul, Yusuf Ziya

    2018-03-20

    A new diffraction field expression is introduced with the aid of the modified theory of physical optics for a wedge with different face impedances. First, the scattered geometrical optics fields are determined when both faces of the wedge are illuminated by the incident wave. The geometrical optics waves are then expressed in terms of the sum of two different fields that occur for different impedance wedges. The diffracted fields are determined for the two cases separately, and the total diffracted field is obtained as a sum of these waves. Lastly, the uniform field expressions are obtained, and the resultant fields are numerically compared with the solution of Maliuzhinets.

  17. Intercomparison of wedge factor for symmetric field and asymmetric field used 6MV linac

    International Nuclear Information System (INIS)

    Ji, Youn Sang; Han, Jae Jin

    1999-01-01

    Therapy equipment have taken progress for Cancer make use of Radiation for the normal tissue system make much of important for shielding. In modern times independent jaw setting to used equipment as possible make use of asymmetric field. Therefore, the asymmetric field be leave out of consideration wedge factor because of with used wedge for the most of part. These experimentation find out have an effect on the dosimetry of out put compared with of the difference between the symmetric field and asymmetric field for the wedge factor

  18. Evaluation of wedge-shaped phantoms for assessment of scanner display as a part of quality control of scanner performance

    International Nuclear Information System (INIS)

    Bergmann, H.; Havlik, E.

    1981-01-01

    Image manipulation in modern rectilinear scanners comprises background subtraction and contrast enhancement facilities. It has been the aim of this investigation to develop simple quality assurance methods suitable for checking the function of these features on a routine basis. Several types of phantoms have been investigated: an absorption step wedge, an emission step wedge and an emission continuous wedge. The absorption step wedge when used with a usual gamma-camera checking source gave the least satisfactory results. The emission step wedge is best suited for test procedures for background subtraction of the colour printer display and for contrast enhancement of the photo display, whereas the emission continuous wedge gave best results in testing the contrast enhancement of the colour printer display. An evaluation of the relative merits of the phantoms indicates that the emission step wedge is best suited for quality assurance tests. (author)

  19. The influence of wedge diffuser blade number and divergence angle on the performance of a high pressure ratio centrifugal compressor

    Science.gov (United States)

    Wang, Yi; Han, Ge; Lu, Xingen; Zhu, Junqiang

    2018-02-01

    Wedge diffuser is widely used in centrifugal compressors due to its high performance and compact size. This paper is aimed to research the influence of wedge diffuser blade number and divergence angle on centrifugal compressor performance. The impact of wedge diffuser blade number on compressor stage performance is investigated, and then the wedge diffusers with different divergence angle are studied by varying diffuser wedge angle and blade number simultaneously. It is found that wedge diffuser with 27 blades could have about 0.8% higher adiabatic efficiency and 0.14 higher total pressure ratio than the wedge diffuser with 19 blades and the best compressor performance is achieved when diffuser divergence angle is 8.3°.These results could give some advices on centrifugal compressor design.

  20. The evidence for synthesis of truncated triangular silver nanoplates in the presence of CTAB

    International Nuclear Information System (INIS)

    He Xin; Zhao Xiujian; Chen Yunxia; Feng Jinyang

    2008-01-01

    Truncated triangular silver nanoplates were prepared by a solution-phase approach, which involved the seed-mediated growth of silver nanoparticles in the presence of cetyltrimethylammonium bromide (CTAB) at 40 deg. C. The result of X-ray diffraction indicates that the as-prepared nanoparticles are made of pure face centered cubic silver. Transmission electron microscopy and atomic force microscopy studies show that the truncated triangular silver nanoplates, with edge lengths of 50 ± 5 nm and thicknesses of 27 ± 3 nm, are oriented differently on substrates of a copper grid and a fresh mica flake. The corners of these nanoplates are round. The selected area electron diffraction analysis reveals that the silver nanoplates are single crystals with an atomically flat surface. We determine the holistic morphology of truncated triangular silver nanoplates through the above measurements with the aid of computer-aided 3D perspective images

  1. Polarizing beam splitter of deep-etched triangular-groove fused-silica gratings.

    Science.gov (United States)

    Zheng, Jiangjun; Zhou, Changhe; Feng, Jijun; Wang, Bo

    2008-07-15

    We investigated the use of a deep-etched fused-silica grating with triangular-shaped grooves as a highly efficient polarizing beam splitter (PBS). A triangular-groove PBS grating is designed at a wavelength of 1550 nm to be used in optical communication. When it is illuminated in Littrow mounting, the transmitted TE- and TM-polarized waves are mainly diffracted in the minus-first and zeroth orders, respectively. The design condition is based on the average differences of the grating mode indices, which is verified by using rigorous coupled-wave analysis. The designed PBS grating is highly efficient over the C+L band range for both TE and TM polarizations (>97.68%). It is shown that such a triangular-groove PBS grating can exhibit a higher diffraction efficiency, a larger extinction ratio, and less reflection loss than the binary-phase fused-silica PBS grating.

  2. An approach to decision-making with triangular fuzzy reciprocal preference relations and its application

    Science.gov (United States)

    Meng, Fanyong

    2018-02-01

    Triangular fuzzy reciprocal preference relations (TFRPRs) are powerful tools to denoting decision-makers' fuzzy judgments, which permit the decision-makers to apply triangular fuzzy ratio rather than real numbers to express their judgements. Consistency analysis is one of the most crucial issues in preference relations that can guarantee the reasonable ranking order. However, all previous consistency concepts cannot well address this type of preference relations. Based on the operational laws on triangular fuzzy numbers, this paper introduces an additive consistency concept for TFRPRs by using quasi TFRPRs, which can be seen as a natural extension of the crisp case. Using this consistency concept, models to judging the additive consistency of TFRPRs and to estimating missing values in complete TFRPRs are constructed. Then, an algorithm to decision-making with TFRPRs is developed. Finally, two numerical examples are offered to illustrate the application of the proposed procedure, and comparison analysis is performed.

  3. Effect of triangular vacancy defect on thermal conductivity and thermal rectification in graphene nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ping, E-mail: yangpingdm@ujs.edu.cn [Laboratory of Advanced Manufacturing and Reliability for MEMS/NEMS/OEDS, Jiangsu University, Zhenjiang 212013 (China); Li, Xialong; Zhao, Yanfan [Laboratory of Advanced Manufacturing and Reliability for MEMS/NEMS/OEDS, Jiangsu University, Zhenjiang 212013 (China); Yang, Haiying [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang, Shuting, E-mail: wangst@mail.hust.edu.cn [School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2013-11-01

    We investigate the thermal transport properties of armchair graphene nanoribbons (AGNRs) possessing various sizes of triangular vacancy defect within a temperature range of 200–600 K by using classical molecular dynamics simulation. The results show that the thermal conductivities of the graphene nanoribbons decrease with increasing sizes of triangular vacancy defects in both directions across the whole temperature range tested, and the presence of the defect can decrease the thermal conductivity by more than 40% as the number of removed cluster atoms is increased to 25 (1.56% for vacancy concentration) owing to the effect of phonon–defect scattering. In the meantime, we find the thermal conductivity of defective graphene nanoribbons is insensitive to the temperature change at higher vacancy concentrations. Furthermore, the dependence of temperatures and various sizes of triangular vacancy defect for the thermal rectification ration are also detected. This work implies a possible route to achieve thermal rectifier for 2D materials by defect engineering.

  4. Topological magnon bands and unconventional thermal Hall effect on the frustrated honeycomb and bilayer triangular lattice.

    Science.gov (United States)

    Owerre, S A

    2017-09-27

    In the conventional ferromagnetic systems, topological magnon bands and thermal Hall effect are due to the Dzyaloshinskii-Moriya interaction (DMI). In principle, however, the DMI is either negligible or it is not allowed by symmetry in some quantum magnets. Therefore, we expect that topological magnon features will not be present in those systems. In addition, quantum magnets on the triangular-lattice are not expected to possess topological features as the DMI or spin-chirality cancels out due to equal and opposite contributions from adjacent triangles. Here, however, we predict that the isomorphic frustrated honeycomb-lattice and bilayer triangular-lattice antiferromagnetic system will exhibit topological magnon bands and topological thermal Hall effect in the absence of an intrinsic DMI. These unconventional topological magnon features are present as a result of magnetic-field-induced non-coplanar spin configurations with nonzero scalar spin chirality. The relevance of the results to realistic bilayer triangular antiferromagnetic materials are discussed.

  5. Triangularly arranged heat exchanger bundles to restrain wind effects on natural draft dry cooling system

    International Nuclear Information System (INIS)

    Liao, H.T.; Yang, L.J.; Du, X.Z.; Yang, Y.P.

    2016-01-01

    Highlights: • Triangularly arranged heat exchanger around the dry-cooling tower is proposed. • By coupling condenser with dry cooling system, TACHE performance is obtained. • At low wind speeds, cooling performance with TACHE is inferior to that with CACHE. • Better performance can be achieved for cooling system with TACHE at high wind speeds. • TACHE can be applied to the region with the strong prevailing wind all year around. - Abstract: It has been commonly recognized that the crosswind may deteriorate the cooling performance of the natural draft dry cooling system with vertically arranged heat exchanger bundles around the circumference of dry-cooling tower. With the purpose for restraining the adverse effects of ambient winds, a novel triangular configuration of heat exchanger bundles is proposed in this work. The air-side flow and heat transfer models coupled with the circulating water heat transfer process are developed for two kinds of natural draft dry cooling systems with the conventional circularly arranged and novel triangularly arranged heat exchanger bundles, by which the flow and temperature fields, mass flow rate of cooling air, outlet water temperature of heat exchanger and turbine back pressure are obtained. Three wind directions of 0°, 90°, and 180° are investigated at various wind speeds for the natural draft dry cooling system with triangularly arranged heat exchanger bundles, which are compared with the conventional system with circularly arranged heat exchanger bundles. The results show that the thermo-flow performances of the natural draft dry cooling system with triangularly arranged heat exchanger get improved significantly at high wind speeds and in the wind direction of 180°, thus a low turbine back pressure can be achieved, which is of benefit to the energy efficiency of the power generating unit. The natural draft dry cooling system with triangularly arranged heat exchanger is recommended to apply to the regions with

  6. Enhanced dynamic wedge and independent monitor unit verification

    International Nuclear Information System (INIS)

    Howlett, SJ.

    2005-01-01

    Some serious radiation accidents have occurred around the world during the delivery of radiotherapy treatment. The regrettable incident in Panama clearly indicated the need for independent monitor unit (MU) verification. Indeed the International Atomic Energy Agency (IAEA), after investigating the incident, made specific recommendations for radiotherapy centres which included an independent monitor unit check for all treatments. Independent monitor unit verification is practiced in many radiotherapy centres in developed countries around the world. It is mandatory in USA but not yet in Australia. This paper describes development of an independent MU program, concentrating on the implementation of the Enhanced Dynamic Wedge (EDW) component. The difficult case of non centre of field (COF) calculation points under the EDW was studied in some detail. Results of a survey of Australasian centres regarding the use of independent MU check systems is also presented. The system was developed with reference to MU calculations made by Pinnacle 3 D Radiotherapy Treatment Planning (RTP) system (ADAC - Philips) for 4MV, 6MV and 18MV X-ray beams used at the Newcastle Mater Misericordiae Hospital (NMMH) in the clinical environment. A small systematic error was detected in the equation used for the EDW calculations. Results indicate that COF equations may be used in the non COF situation with similar accuracy to that achieved with profile corrected methods. Further collaborative work with other centres is planned to extend these findings

  7. Canonical quantization of the Proca field in the Rindler wedge

    International Nuclear Information System (INIS)

    Castineiras, Jorge; Correa, Emerson Benedito Sousa; Crispino, Luis Carlos Bassalo; Matsas, George Emanuel Avraam

    2009-01-01

    Full text. We perform the canonical quantization of a massive vector field in Rindler spacetime. We pay special attention to the zero frequency modes of the Proca field because these are the modes that interact with structureless sources which are static in the Rindler spacetime. Our motivation is the computation of the total response of a static source with some fixed proper acceleration a 0 in Rindler spacetime interacting with the zero energy massive vector particle of the Fulling-Davies-Unruh (FDU) thermal bath and compare it with the response of a static source with the same proper acceleration a 0 outside a Schwarzschild black hole interacting with the massive vector particles of the Hawking thermal radiation. Surprisingly, as it was already shown in a resent article, these responses would be identical if a massless scalar field is consider instead of the massive vector field, the field outside the Schwarzschild black hole is supposed to be in the Unruh vacuum and the source proper acceleration is the same in both cases. This came as a surprise because structureless static sources can only interact with zero-frequency field modes. Such modes can probe the global geometry of spacetime and are accordingly quite different in Schwarzschild spacetime and in the Rindler wedge. (author)

  8. A teoria triangular do amor de Sternberg e o modelo dos cinco grandes fatores Sternberg's triangular theory of love and the big five factor model

    Directory of Open Access Journals (Sweden)

    Bruna Gomes Mônego

    2011-04-01

    Full Text Available O presente estudo investigou a influência dos traços de personalidade de acordo com o modelo dos Cinco Grandes Fatores (CGF e do amor segundo a Teoria Triangular do Amor de Sternberg na satisfação conjugal. A amostra foi composta por 192 universitários que vivenciavam um relacionamento amoroso classificado como ficante, namoro/noivado ou casamento. Os participantes responderam coletivamente à Escala Fatorial de Satisfação em Relacionamento de Casal, à Escala Triangular do Amor de Sternberg e à Bateria Fatorial de Personalidade. Os resultados indicaram padrões diferentes de correlação para cada tipo de relacionamento e o modelo de Regressão Linear Múltipla foi significativo (F=23,19, gl=10, pThis present study investigated the influence of personality traits according to the Big Five Factors (CGF model and to love according to Sternberg's Triangular Theory of Love in marital satisfaction. Sample was composed by 192 undergraduate students who experienced a loving relationship classified as an informal relationship, dating/engagement or wedding. Participants answered the "Escala Fatorial de Satisfação em Relacionamento de Casal", the Sternberg's Triangular Love Scale and the "Bateria Fatorial de Personalidade". Data showed different patterns of correlation for each type of relationship and multiple linear regression model was significant (F=23.19, df=10, p<0.001 and explained 58% of the variance. The intimacy, passion and conscientiousness constructs contributed positively to the satisfaction, while neuroticism had a negative influence. The commitment component and the other personality traits did not reach statistical significance.

  9. Solution of two-dimensional neutron diffusion equation for triangular region by finite Fourier transformation

    International Nuclear Information System (INIS)

    Kobayashi, Keisuke; Ishibashi, Hideo

    1978-01-01

    A two-dimensional neutron diffusion equation for a triangular region is shown to be solved by the finite Fourier transformation. An application of the Fourier transformation to the diffusion equation for triangular region yields equations whose unknowns are the expansion coefficients of the neutron flux and current in Fourier series or Legendre polynomials expansions only at the region boundary. Some numerical calculations have revealed that the present technique gives accurate results. It is shown also that the solution using the expansion in Legendre polynomials converges with relatively few terms even if the solution in Fourier series exhibits the Gibbs' phenomenon. (auth.)

  10. Tokamak equilibria with non-parallel flow in a triangularity-deformed axisymmetric toroidal coordinate system

    Directory of Open Access Journals (Sweden)

    Ap Kuiroukidis

    2018-01-01

    Full Text Available We consider a generalized Grad–Shafranov equation (GGSE in a triangularity-deformed axisymmetric toroidal coordinate system and solve it numerically for the generic case of ITER-like and JET-like equilibria with non-parallel flow. It turns out that increase of the triangularity improves confinement by leading to larger values of the toroidal beta and the safety factor. This result is supported by the application of a criterion for linear stability valid for equilibria with flow parallel to the magnetic field. Also, the parallel flow has a weaker stabilizing effect.

  11. Solution of two energy-group neutron diffusion equation by triangular elements

    International Nuclear Information System (INIS)

    Correia Filho, A.

    1981-01-01

    The application of the triangular finite elements of first order in the solution of two energy-group neutron diffusion equation in steady-state conditions is aimed at. The EFTDN (triangular finite elements in neutrons diffusion) computer code in FORTRAN IV language is developed. The discrete formulation of the diffusion equation is obtained applying the Galerkin method. The power method is used to solve the eigenvalues' problem and the convergence is accelerated through the use of Chebshev polynomials. For the equation systems solution the Gauss method is applied. The results of the analysis of two test-problems are presented. (Author) [pt

  12. Mode I Stress Intensity Factors for triangular corner crack nearby intersecting of cylindrical holes

    Directory of Open Access Journals (Sweden)

    E. Salvati

    2013-10-01

    Full Text Available In this paper triangular flaws has been taken into account at the intersection of two holes inside a specified specimen. Influence of bore hole D1/D2 and angle between their axes α are examined. Numerical analysis are performed to determine Stress Intensity factors (SIF in many geometric configurations. Afterwards, fitting weight function’s parameters with FEM results, new SIF analytics expression are shown. Finally, the accuracy of weight functions in SIF predictions for different inner pressure, has been checked as well as the comparison between the SIF of a triangular crack and that of an actual crack shape obtained through a fatigue test.

  13. Measurement of dynamic wedge angles and beam profiles by means of MRI ferrous sulphate gel dosimetry

    Science.gov (United States)

    Bengtsson, Magnus; Furre, Torbjørn; Rødal, Jan; Skretting, Arne; Olsen, Dag R.

    1996-02-01

    The purpose of this study is to examine the possible value of measuring the dose distribution in dynamic wedge photon beams using ferrous sulphate gel phantoms analysed by MRI. The wedge angles and dose profiles were measured for a field size of and for dynamic wedge angles of , , and using a 15 MV photon beam generated from a Clinac 2100 CD (Varian). The dose profiles obtained from MRI ferrous sulphate gel were in good agreement with the dose measurements performed with a diode detector array. Also, the wedge angles determined from the MRI ferrous sulphate gel agreed well with the values obtained by using film dosimetry and with calculations by use of TMS (treatment planning system) (Helax, Uppsala, Sweden). The study demonstrated that MRI ferrous sulphate gel dosimetry is an adequate tool for measurements of some beam characteristics of dynamic radiation fields.

  14. Reduced emissions of greenhouse gases 2050: Technological wedges - Input to the Commission on Low Emissions

    International Nuclear Information System (INIS)

    Rosenberg, Eva; Espegren, Kari Aamodt; Finden, Per; Hageman, Rolf; Stenersen, Dag

    2006-09-01

    The Commission on Low Emissions was established in March 2005 and has been charged with the task of describing how Norway can achieve a 50-80 percent reduction in emissions of greenhouse gases by 2050. The commission describes the desired total reduction in emissions to be a set of actions or 'wedges', meaning that the reduction in emissions are linked to an array of technological and behavioural changes. The technological wedges are described here, while the behavioural wedges are treated in a different report. The potentials described are based on the Low Emission's reference line. Possible changes in the reference line will result in changed potentials. The technological wedges studied comprise to a great extent a potential of 50-80 percent reduction in greenhouse gases by 2050. This depends on considerable effort from research and development, and a determination to change external conditions

  15. Development of Cone Wedge Ring Expansion Test to Evaluate Mechanical Properties of Clad Tubing Structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-10-01

    To determine the hoop tensile properties of irradiated fuel cladding in a hot cell, a cone wedge ring expansion test method was developed. A four-piece wedge insert was designed with tapered angles matched to the cone shape of a loading piston. The ring specimen was expanded in the radial direction by the lateral expansion of the wedges under the downward movement of the piston. The advantages of the proposed method are that implementation of the test setup in a hot cell is simple and easy, and that it enables a direct strain measurement of the test specimen from the piston’s vertical displacement soon after the wedge-clad contact resistance is initiated.

  16. Diffraction of an inhomogeneous plane wave by an impedance wedge in a lossy medium

    CSIR Research Space (South Africa)

    Manara, G

    1998-11-01

    Full Text Available The diffraction of an inhomogeneous plane wave by an impedance wedge embedded in a lossy medium is analyzed. The rigorous integral representation for the field is asymptotically evaluated in the context of the uniform geometrical theory...

  17. Wedge and subselective pulmonary angiography in pulmonary hypertension secondary to venous obstruction

    International Nuclear Information System (INIS)

    Bowen, J.S.; Bookstein, J.J.; Johnson, A.D.; Peterson, K.L.; Moser, K.M.

    1985-01-01

    Pulmonary wedge or subselective angiography provided key diagnostic information in two cases of pulmonary hypertension secondary to pulmonary venous obstruction. Whereas conventional pulmonary angiograms and ventilation-perfusion lung scans were interpreted as showing embolism, plain radiographs demonstrated Kerley B lines, suggesting venous obstruction. Subselective or wedge angiography of nonopacified arteries verified their anatomical patency and also revealed venous stenoses, collaterals, and atrophy indicative of obstruction

  18. Improved field abutment-wedge design for 6-MV x-rays

    International Nuclear Information System (INIS)

    Nyerick, C.E.; Steadham, R.E.

    1989-01-01

    This paper presents an improved abutment wedge for matching large photon fields. The wedge is used with a 6-MV Linac accelerator and generates a 5-cm pseudopenumbra at the 50% relative dose juncture. The features allow treatment of fields up to 40 cm long in any fractional step of increment, simultaneous generation of two wide penumbrae or one wide and one sharp penumbra, and attachment of the device downstream of standard beam-shaping accessories in any 90 degrees angular orientation

  19. The application of wedge type compensation filter for uniform density on the endoscopic retrograde pancreatography

    International Nuclear Information System (INIS)

    Son, Soon Yong; Lee, Hee Jeong; Lee, Won Hong; Cho, Cheong Chan; Ryu, Meung Sun; Jung, Hong Ryang

    2001-01-01

    Over-density of pancreatic duct tail part on the endoscopic retrograde pancreatogram results from patient's position and inserted air during the study. The aim of this paper is to decide the filter angle to obtain an uniform density. Endoscopic retrograde pancratography was performed to 234 patients, and angled wedge filter was used differently. They are 10 deg (47), 20 deg (45), 30 deg (50). We also did not use wedge filter to 42 patients. We decided reliance degree in 95%. The statistical difference was p<0.05. The patients' sex rate was 1.8:1 between 18 and 87 years old(average age 58 years). Their body girth was 18.71 cm on the average. Of total 234 patients, difference of right and left average density was 0.01 by 30 deg wedge filter, -0.08 40 deg wedge filter and 0.27 non-wedge filter. These average values of difference density were very significant statistically, and standard deviation also was close to regular distribution. In conclusion, there is a usefulness of angled wedge filter for increasing diagnostic value of pancreatic duct tail part on the endoscopic retrograde pancreatogram

  20. Porous Titanium Wedges in Lateral Column Lengthening for Adult-Acquired Flatfoot Deformity.

    Science.gov (United States)

    Moore, Spencer H; Carstensen, S Evan; Burrus, M Tyrrell; Cooper, Truitt; Park, Joseph S; Perumal, Venkat

    2017-10-01

    Lateral column lengthening (LCL) is a common procedure for reconstruction of stage II flexible adult-acquired flatfoot deformity (AAFD). The recent development of porous titanium wedges for this procedure provides an alternative to allograft and autograft. The purpose of this study was to report radiographic and clinical outcomes achieved with porous titanium wedges in LCL. A retrospective analysis of 34 feet in 30 patients with AAFD that received porous titanium wedges for LCL from January 2011 to October 2014. Deformity correction was assessed using both radiographic and clinical parameters. Radiographic correction was assessed using the lateral talo-first metatarsal angle, the talonavicular uncoverage percentage, and the first metatarsocuneiform height. The hindfoot valgus angle was measured. Patients were followed from a minimum of 6 months up to 4 years (mean 16.1 months). Postoperative radiographs demonstrated significant correction in all 3 radiographic criteria and the hindfoot valgus angle. We had no cases of nonunion, no wedge migration, and no wedges have been removed to date. The most common complication was calcaneocuboid joint pain (14.7%). Porous titanium wedges in LCL can achieve good radiographic and clinical correction of AAFD with a low rate of nonunion and other complications. Level IV: Case series.

  1. On the practice of the clinical implementation of enhanced dynamic wedges

    International Nuclear Information System (INIS)

    Koken, Phil W.; Heukelom, Stan; Cuijpers, Johan P.

    2003-01-01

    Practical aspects of the clinical implementation of enhanced dynamic wedges (EDW) replacing manual wedges are presented and discussed extensively. A comparison between measured and calculated data is also presented. Relative dose distributions and wedge factors were calculated with a commercially available treatment planning system and measured in a water-phantom and with an ionization chamber. Wedge factor calculations and measurements were also compared with an independent method of wedge factor calculations available from the literature. Aspects of the clinical implementation, such as safety and quality assurance, were evaluated. Measurements and calculations agreed very well and were slightly better than results of previous studies. Profiles and percentage depth doses (PDDs) agreed within 1% to 1.5% and within 0.5%, respectively. Measured and calculated wedge factors ratios agreed within 0.5% to 1%. Calculated and measured EDW dose distributions showed excellent agreement, both relative and absolute. However, for safe and practical use, specific aspects need to be taken into consideration. Once the treatment planning system is commissioned properly, the clinical implementation of EDW is rather straightforward

  2. Evaluation method of lead measurement accuracy of gears using a wedge artefact

    International Nuclear Information System (INIS)

    Komori, Masaharu; Takeoka, Fumi; Kubo, Aizoh; Okamoto, Kazuhiko; Osawa, Sonko; Sato, Osamu; Takatsuji, Toshiyuki

    2009-01-01

    The reduction of the vibration and noise of gears is an important issue in mechanical devices such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are markedly affected by deviations of the tooth flank form of micrometre order; therefore, a strict quality control of the tooth flank form is required. The accuracy of the lead measurement for a gear-measuring instrument is usually evaluated using a master gear or a lead master. However, it is difficult to manufacture masters with high accuracy because the helix is a complicated geometrical form. In this paper, we propose a method of evaluating a gear-measuring instrument using a wedge artefact, which includes a highly precise plane surface. The concept of the wedge artefact is described and a mathematical model of the measuring condition of the wedge artefact is constructed. Theoretical measurement results for the wedge artefact are calculated. The wedge artefact is designed and produced on the basis of the theoretical measurement results. A measurement experiment using the wedge artefact is carried out and its effectiveness is verified

  3. The Triangular Sign, a Useful Diagnostic Marker for Biliary Atresia: A Case Series of Three Irish Infants

    LENUS (Irish Health Repository)

    Smith, A

    2018-06-01

    The triangular cord (TC) sign is the appearance of a triangular shaped echogenic density visualised immediately cranial to the portal vein bifurcation on ultrasonographic examination. Several studies have reported that this ultrasonographic sign is a reliable and helpful marker in identifying Biliary Atresia (BA).

  4. Cyclicity, episodicity, and continuity in accretionary wedge evolution: insights from geophysical imaging and physical analogue experiments

    Science.gov (United States)

    Kukowski, N.

    2009-04-01

    Geophysical profiles across active convergent margins reveal different styles and locations of sediment accretion, thrust slices dipping successively steeper towards the hinterland, splay faults, and blind thrusts as well as accumulation spaces e. g. thrust top basins and larger basins formed by regional subsidence, of very variable size and position. Morphologically, the continental slope at most margins can be sub-divided in a lower, middle, and upper slope, with often the middle slope being the most shallowly inclined, suggesting segmented wedges. Beneath the forearc, a subduction channel of a few hundred meters to a few km thickness marks a layer of material transport into greater depth that also hosts the plate interface and décollement zone. The petrographical composition of accretionary wedges and subduction channels as well as related pressures and temperatures are accessible through deep drilling or sampling fossil accretionary complexes now exhumed. The structure, lithology, and tectonic history of forearcs as identified from geophysical and geology field observations hint to parameters possibly controlling material transfer at convergent margins. Among them, sediment supply, which itself is largely controlled by climate, width of the subduction channel, and interplate frictional properties, which also exhibit control on plate coupling and therefore the seismic potential of a forearc, are suggested to be of major importance. These parameters further may undergo temporal fluctuation, e.g. when climate changes or when different material is entering the trench and therefore potentially also the subduction channel. High resolution monitoring of material flux and the evolution of fault zone kinematics of analogue experimental wedges made of granular materials exhibiting frictional behaviour equivalent to that of upper crustal rocks shows that accretionary cycles proceed as a chain of sub-processes, i.e. the development of a thrust slice from initial failure

  5. The correlation of initial radiographic characteristics of distal radius fractures and injuries of the triangular fibrocartilage complex.

    Science.gov (United States)

    Kasapinova, K; Kamiloski, V

    2016-06-01

    Our purpose was to determine the correlation of initial radiographic parameters of a distal radius fracture with an injury of the triangular fibrocartilage complex. In a prospective study, 85 patients with surgically treated distal radius fractures were included. Wrist arthroscopy was used to identify and classify triangular fibrocartilage complex lesions. The initial radial length and angulation, dorsal angulation, ulnar variance and distal radioulnar distance were measured. Wrist arthroscopy identified a triangular fibrocartilage complex lesion in 45 patients. Statistical analysis did not identify a correlation with any single radiographic parameter of the distal radius fractures with the associated triangular fibrocartilage complex injuries. The initial radiograph of a distal radius fracture does not predict a triangular fibrocartilage complex injury. III. © The Author(s) 2016.

  6. Flow in a triangular open channel with hydraulic jump | Eyo | Journal ...

    African Journals Online (AJOL)

    Mathematical model for dredging a triangular open channel with hydraulic jump is developed using the method of successive approximation. Applying the model to a numerical example new parameters of the new (excavated) channel are determined and compared with those of the original channel. Another feature of the ...

  7. Synthesis of circular and triangular gold nanorings with tunable optical properties

    KAUST Repository

    Lin, Xiaoying

    2017-08-24

    This communication describes a robust wet-chemical synthetic strategy for the preparation of monodispersed circular and triangular gold nanorings. The localized surface plasmon resonance of the nanorings can be tuned by controlling the outer diameter and ridge thickness of the nanorings.

  8. Turbulent heat transfer to longitudinal flow through a triangular array of circular rods

    International Nuclear Information System (INIS)

    Pfann, J.

    1975-01-01

    Temperature distribution and heat transfer to longitudinal turbulent, fully developed flow through triangular arrays of smooth circular rods are analysed for liquids with Prandtl number approximately 1 and << 1. Nusselt number is plotted versus pitch and turbulence for constant heat flow and for constant temperature on the rod surface, and the optimum pitch is determined. The influence of Prandtl number is analysed. (Auth.)

  9. A Triangular Approach to Integrate Research, Education and Practice in Higher Engineering Education

    Science.gov (United States)

    Heikkinen, Eetu-Pekka; Jaako, Juha; Hiltunen, Jukka

    2017-01-01

    Separate approaches in engineering education, research and practice are not very useful when preparing students for working life; instead, integration of education, research and industrial practices is needed. A triangular approach (TA) as a method to accomplish this integration and as a method to provide students with integrated expertise is…

  10. Breaking away from the Pack: Positioning the Marketing Discipline through a Triangular Analysis.

    Science.gov (United States)

    Bonnici, Joseph L.; Reddy, Allan C.

    1993-01-01

    College and university marketing departments should use the technique of positioning to increase enrollments. The triangular approach to positioning uses close scrutiny of the student profile, the benefits marketing courses offer, and the competition the department faces within and outside the business school. The technique can also be used by…

  11. Development of internal transport barrier scenarios at ITER-relevant high triangularity in JET

    International Nuclear Information System (INIS)

    Rimini, F.G.; Becoulet, M.; Giovannozzi, E.; Lomas, P.J.; Tudisco, O.; Alper, B.; Crisanti, F.; Baar, M. de; Luna, E. de La; Vries, P. de; Ekedahl, A.; Hawkes, N.; Huysmans, G.; Litaudon, X.; Parail, V.; Saibene, G.; Tuccillo, A.A.; Zastrow, K.D.

    2005-01-01

    The development of scenarios characterized by H-mode confinement and internal transport barriers (ITBs) in high triangularity, δ ∼ 0.4-0.5, discharges is of particular interest for ITER advanced tokamak operation. Previous JET experiments have shown that high triangularity favours H-modes which are ELM-free or develop type I edge localized mode (ELM) activity, which inhibits long lasting ITBs. The recent experiments reported here concentrate on integrated optimization of edge and core conditions. The stability of the edge pedestal was controlled using gas injection, deuterium or light impurities, and plasma current ramps. Both methods yield more ITB-friendly edge pedestal conditions, varying from small type I to type III ELMs and, in extreme cases, resulting in L-mode. In parallel, the conditions for triggering and sustaining ITBs encompassing a large proportion of the plasma volume (outer ITBs) were optimized, as opposed to less performing ITBs located closer to the plasma centre (inner ITB). These plasmas have deeply reversed target current profiles with q min ∼ 3 and a narrow inner ITB, located typically at a small normalized radius ρ E , at q 95 = 7.5, H 89 β N ∼ 3.5-4 and ∼60% of the Greenwald density limit. In summary, a high triangularity scenario has been developed, which combines the desirable characteristics of controlled edge, long lasting wide ITBs and high performance at density higher than the low triangularity JET scenarios

  12. Triangular M/G/1-type and tree-like QBD Markov chains

    NARCIS (Netherlands)

    Van Houdt, B.; Leeuwaarden, van J.S.H.

    2009-01-01

    In applying matrix-analytic methods to M/G/1-type and tree-like QBD Markov chains, it is crucial to determine the solution to a (set of) nonlinear matrix equation(s). This is usually done via iterative methods. We consider the highly structured subclass of triangular M/G/1-type and tree-like QBD

  13. An experimental investigation of head loss through a triangular “V- shaped” screen

    Directory of Open Access Journals (Sweden)

    Mahmoud Zayed

    2018-03-01

    Full Text Available Common traditional screens (screens perpendicular and vertical to the flow direction face extensive problems with screen blockage, which can result in adverse hydraulic, environmental, and economic consequences. Experimentally, this paper presents an advanced trash screen concept to reduce traditional screen problems and improve the hydraulic performance of screens. The traditional screen is re-developed using a triangular V shape with circular bars in the flow direction. Triangular V-shaped screen models with different angles, blockage ratios, circular bar designs, and flow discharges were tested in a scaled physical model. The analyses provide promising results. The findings showed that the head loss coefficients were effectively reduced by using the triangular V-shaped screens with circular bars (α < 90° in comparison with the traditional trash screen (α = 90. Additionally, the results indicated that the head loss across the screen increased with increasing flow discharge and blockage ratio. The losses considerably increase by large percentages when the screen becomes blocked by 40%. Low head losses were recorded at low screen angles for the circular bars. A new head loss equation is recommended for triangular screens with circular bars.

  14. Modeling the Pathophysiology of Phonotraumatic Vocal Hyperfunction with a Triangular Glottal Model of the Vocal Folds

    Science.gov (United States)

    Galindo, Gabriel E.; Peterson, Sean D.; Erath, Byron D.; Castro, Christian; Hillman, Robert E.; Zañartu, Matías

    2017-01-01

    Purpose: Our goal was to test prevailing assumptions about the underlying biomechanical and aeroacoustic mechanisms associated with phonotraumatic lesions of the vocal folds using a numerical lumped-element model of voice production. Method: A numerical model with a triangular glottis, posterior glottal opening, and arytenoid posturing is…

  15. Synthesis of circular and triangular gold nanorings with tunable optical properties

    KAUST Repository

    Lin, Xiaoying; Liu, Yi; Lin, Meihua; Zhang, Qian; Nie, Zhihong

    2017-01-01

    This communication describes a robust wet-chemical synthetic strategy for the preparation of monodispersed circular and triangular gold nanorings. The localized surface plasmon resonance of the nanorings can be tuned by controlling the outer diameter and ridge thickness of the nanorings.

  16. Notes on TQFT wire models and coherence equations for SU(3) triangular cells

    CERN Document Server

    Coquereaux, R.; Schieber, G.

    2010-01-01

    After a summary of the TQFT wire model formalism we bridge the gap from Kuperberg equations for SU(3) spiders to Ocneanu coherence equations for systems of triangular cells on fusion graphs that describe modules associated with the fusion category of SU(3) at level k. We show how to solve these equations in a number of examples.

  17. Continuous weakly cancellative triangular subnorms: I. Their web-geometric properties

    Czech Academy of Sciences Publication Activity Database

    Petrík, Milan; Sarkoci, Peter

    2018-01-01

    Roč. 332, 1 February (2018), s. 93-110 ISSN 0165-0114 R&D Projects: GA ČR GJ15-07724Y Institutional support: RVO:67985807 Keywords : associativity * conditionally cancellative * continuous triangular subnorm * contour * level set * Reidemeister closure condition * weakly cancellative * web geometry Subject RIV: BA - General Mathematics Impact factor: 2.718, year: 2016

  18. Three-dimensional vertebral wedging in mild and moderate adolescent idiopathic scoliosis.

    Directory of Open Access Journals (Sweden)

    Sophie-Anne Scherrer

    Full Text Available Vertebral wedging is associated with spinal deformity progression in adolescent idiopathic scoliosis. Reporting frontal and sagittal wedging separately could be misleading since these are projected values of a single three-dimensional deformation of the vertebral body. The objectives of this study were to determine if three-dimensional vertebral body wedging is present in mild scoliosis and if there are a preferential vertebral level, position and plane of deformation with increasing scoliotic severity.Twenty-seven adolescent idiopathic scoliotic girls with mild to moderate Cobb angles (10° to 50° participated in this study. All subjects had at least one set of bi-planar radiographs taken with the EOS® X-ray imaging system prior to any treatment. Subjects were divided into two groups, separating the mild (under 20° from the moderate (20° and over spinal scoliotic deformities. Wedging was calculated in three different geometric planes with respect to the smallest edge of the vertebral body.Factorial analyses of variance revealed a main effect for the scoliosis severity but no main effect of vertebral Levels (apex and each of the three vertebrae above and below it (F = 1.78, p = 0.101. Main effects of vertebral Positions (apex and above or below it (F = 4.20, p = 0.015 and wedging Planes (F = 34.36, p<0.001 were also noted. Post-hoc analysis demonstrated a greater wedging in the inferior group of vertebrae (3.6° than the superior group (2.9°, p = 0.019 and a significantly greater wedging (p≤0.03 along the sagittal plane (4.3°.Vertebral wedging was present in mild scoliosis and increased as the scoliosis progressed. The greater wedging of the inferior group of vertebrae could be important in estimating the most distal vertebral segment to be restrained by bracing or to be fused in surgery. Largest vertebral body wedging values obtained in the sagittal plane support the claim that scoliosis could be initiated

  19. A possible mechanism for earthquakes found in the mantle wedge of the Nazca subduction zone

    Science.gov (United States)

    Warren, L. M.; Chang, Y.; Prieto, G. A.

    2017-12-01

    Beneath Colombia, the Cauca cluster of intermediate-depth earthquakes extends for 200 km along the trench (3.5°N-5.5°N, 77.0°W-75.3°W) and, with 58 earthquakes per year with local magnitude ML >= 2.5, has a higher rate of seismicity than the subduction zone immediately to the north or south. By precisely locating 433 cluster earthquakes from 1/2010-3/2014 with data from the Colombian National Seismic Network, we found that the earthquakes are located both in a continuous Nazca plate subducting at an angle of 33°-43° and in the overlying mantle wedge. The mantle wedge earthquakes (12% of the earthquakes) form two isolated 40-km-tall columns extending perpendicular to the subducting slab. Using waveform inversion, we computed focal mechanisms for 69 of the larger earthquakes. The focal mechanisms are variable, but the intraslab earthquakes are generally consistent with an in-slab extensional stress axis oriented 25° counterclockwise from the down-dip direction. We suggest that the observed mantle wedge earthquakes are the result of hydrofracture in a relatively cool mantle wedge. This segment of the Nazca Plate is currently subducting at a normal angle, but Wagner et al. (2017) suggested that a flat slab slowly developed in the region between 9-5.9 Ma and persisted until 4 Ma. During flat slab subduction, the overlying mantle wedge typically cools because it is cut off from mantle corner flow. After hydrous minerals in the slab dehydrate, the dehydrated fluid is expelled from the slab and migrates through the mantle wedge. If a cool mantle wedge remains today, fluid dehydrated from the slab may generate earthquakes by hydrofracture, with the mantle wedge earthquakes representing fluid migration pathways. Dahm's (2000) model of water-filled fracture propagation in the mantle wedge shows hydrofractures propagating normal to the subducting slab and extending tens of km into the mantle wedge, as we observe.

  20. Impact of tool wear on cross wedge rolling process stability and on product quality

    Science.gov (United States)

    Gutierrez, Catalina; Langlois, Laurent; Baudouin, Cyrille; Bigot, Régis; Fremeaux, Eric

    2017-10-01

    Cross wedge rolling (CWR) is a metal forming process used in the automotive industry. One of its applications is in the manufacturing process of connecting rods. CWR transforms a cylindrical billet into a complex axisymmetrical shape with an accurate distribution of material. This preform is forged into shape in a forging die. In order to improve CWR tool lifecycle and product quality it is essential to understand tool wear evolution and the physical phenomena that change on the CWR process due to the resulting geometry of the tool when undergoing tool wear. In order to understand CWR tool wear behavior, numerical simulations are necessary. Nevertheless, if the simulations are performed with the CAD geometry of the tool, results are limited. To solve this difficulty, two numerical simulations with FORGE® were performed using the real geometry of the tools (both up and lower roll) at two different states: (1) before starting lifecycle and (2) end of lifecycle. The tools were 3D measured with ATOS triple scan by GOM® using optical 3D measuring techniques. The result was a high-resolution point cloud of the entire geometry of the tool. Each 3D point cloud was digitalized and converted into a STL format. The geometry of the tools in a STL format was input for the 3D simulations. Both simulations were compared. Defects of products obtained in simulation were compared to main defects of products found industrially. Two main defects are: (a) surface defects on the preform that are not fixed in the die forging operation; and (b) Preform bent (no longer straight), with two possible impacts: on the one hand that the robot cannot grab it to take it to the forging stage; on the other hand, an unfilled section in the forging operation.

  1. An experimental study on coolability of a particulate bed with radial stratification or triangular shape

    International Nuclear Information System (INIS)

    Thakre, Sachin; Li, Liangxing; Ma, Weimin

    2014-01-01

    Highlights: • Dryout heat flux of a particulate bed with radial stratification is obtained. • It was found to be dominated by hydrodynamics in the bigger size of particle layer. • Coolability of a particulate bed with triangular shape is investigated. • The coolability is improved in the triangular bed due to lateral ingression of coolant. • Coolability of both beds is enhanced by a downcomer. - Abstract: This paper deals with the results of an experimental study on the coolability of particulate beds with radial stratification and triangular shape, respectively. The study is intended to get an idea on how the coolability is affected by the different features of a debris bed formed in a severe accident of light water reactors. The experiments were performed on the POMECO-HT facility which was constructed to investigate two-phase flow and heat transfer in particulate beds under either top-flooding or bottom-fed condition. A downcomer is designed to enable investigation of the effectiveness of natural circulation driven coolability. Two homogenous beds were also employed in the present study to compare their dryout power densities with those of the radially stratified bed and the triangular bed. The results show that the dryout heat fluxes of the homogeneous beds at top-flooding condition can be predicted by the Reed model. For the radially stratified bed, the dryout heat flux is dominated by two-phase flow in the columns packed with larger particles, and the dryout occurred initially near the boundary between the middle column and a side column. Given the same volume of particles under top-flooding condition, the dryout power density of the triangular bed is about 69% higher than that of the homogenous bed. The coolability of all the beds is enhanced by bottom-fed coolant driven by either forced injection or downcomer-induced natural circulation

  2. An experimental study on coolability of a particulate bed with radial stratification or triangular shape

    Energy Technology Data Exchange (ETDEWEB)

    Thakre, Sachin; Li, Liangxing; Ma, Weimin, E-mail: ma@safety.sci.kth.se

    2014-09-15

    Highlights: • Dryout heat flux of a particulate bed with radial stratification is obtained. • It was found to be dominated by hydrodynamics in the bigger size of particle layer. • Coolability of a particulate bed with triangular shape is investigated. • The coolability is improved in the triangular bed due to lateral ingression of coolant. • Coolability of both beds is enhanced by a downcomer. - Abstract: This paper deals with the results of an experimental study on the coolability of particulate beds with radial stratification and triangular shape, respectively. The study is intended to get an idea on how the coolability is affected by the different features of a debris bed formed in a severe accident of light water reactors. The experiments were performed on the POMECO-HT facility which was constructed to investigate two-phase flow and heat transfer in particulate beds under either top-flooding or bottom-fed condition. A downcomer is designed to enable investigation of the effectiveness of natural circulation driven coolability. Two homogenous beds were also employed in the present study to compare their dryout power densities with those of the radially stratified bed and the triangular bed. The results show that the dryout heat fluxes of the homogeneous beds at top-flooding condition can be predicted by the Reed model. For the radially stratified bed, the dryout heat flux is dominated by two-phase flow in the columns packed with larger particles, and the dryout occurred initially near the boundary between the middle column and a side column. Given the same volume of particles under top-flooding condition, the dryout power density of the triangular bed is about 69% higher than that of the homogenous bed. The coolability of all the beds is enhanced by bottom-fed coolant driven by either forced injection or downcomer-induced natural circulation.

  3. Thermal–structural analysis of ITER triangular support for dominant load verification

    International Nuclear Information System (INIS)

    Kim, Yu-Gyeong; Hwang, Jong-Hyun; Jung, Yung-Jin; Kim, Hyun-Soo; Ahn, Hee-Jae

    2014-01-01

    Highlights: • The load combination method is introduced to thermal–structural analysis for contradictive loads occurred simultaneously. • The one-way coupling analysis also conducted for thermal–structural analysis and its validity is checked by comparing with the load combination. • The dominant load for triangular support bracket is determined as the baking condition. - Abstract: The triangular support is located on the lower inner shell of vacuum vessel of ITER, which should be designed to withstand various loads such as nuclear heat, coolant pressure and so on. The appropriateness of its design is evaluated under the dominant load that could represent the most conservative condition among the design loads. In order to decide the dominant load, a valid method for thermal–structural analysis is firstly verified considering contradictory behaviors between heat and structural loads. In this paper, two approaches; one-way coupling and load combination, are introduced for thermal–structural analysis. The one-way coupling is a method generally used but has a limit to apply on contradictory conditions. The load combination could give a proper solution since it evaluates each load independently and then adds up each result linearly. Based on the results of each case, structural analysis for another load case, baking condition with incident, is conducted to find out which load is dominant for triangular support. Consequently, it is found that the baking condition is the dominant load for triangular support bracket. The proposed load combination method gives a physically reasonable solution which can be used as a reference for checking the validity of other thermal–structural analysis. It is expected that these results could be applied for manufacturing design of the triangular support under various load conditions

  4. Thermal–structural analysis of ITER triangular support for dominant load verification

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu-Gyeong, E-mail: aspirany@hhi.co.kr [Hyundai Heavy Industries Co., Ltd., 1000, Bangeojinsunhwando-ro, Dong-gu, Ulsan (Korea, Republic of); Hwang, Jong-Hyun; Jung, Yung-Jin [Hyundai Heavy Industries Co., Ltd., 1000, Bangeojinsunhwando-ro, Dong-gu, Ulsan (Korea, Republic of); Kim, Hyun-Soo; Ahn, Hee-Jae [National Fusion Research Institute, 113 Gwahangno, Yuseong-gu, Daejeon-si (Korea, Republic of)

    2014-12-15

    Highlights: • The load combination method is introduced to thermal–structural analysis for contradictive loads occurred simultaneously. • The one-way coupling analysis also conducted for thermal–structural analysis and its validity is checked by comparing with the load combination. • The dominant load for triangular support bracket is determined as the baking condition. - Abstract: The triangular support is located on the lower inner shell of vacuum vessel of ITER, which should be designed to withstand various loads such as nuclear heat, coolant pressure and so on. The appropriateness of its design is evaluated under the dominant load that could represent the most conservative condition among the design loads. In order to decide the dominant load, a valid method for thermal–structural analysis is firstly verified considering contradictory behaviors between heat and structural loads. In this paper, two approaches; one-way coupling and load combination, are introduced for thermal–structural analysis. The one-way coupling is a method generally used but has a limit to apply on contradictory conditions. The load combination could give a proper solution since it evaluates each load independently and then adds up each result linearly. Based on the results of each case, structural analysis for another load case, baking condition with incident, is conducted to find out which load is dominant for triangular support. Consequently, it is found that the baking condition is the dominant load for triangular support bracket. The proposed load combination method gives a physically reasonable solution which can be used as a reference for checking the validity of other thermal–structural analysis. It is expected that these results could be applied for manufacturing design of the triangular support under various load conditions.

  5. Chemical risk factors responsible for the formation of wedge-shaped lesions

    Directory of Open Access Journals (Sweden)

    Perić Dejan

    2015-01-01

    Full Text Available Introduction: Non-carious tooth substances loss pose a major health problem of a modern man. The literature often collectively describes all non-carious lesions and is therefore difficult to compare results obtained by different authors. Chemical factors are one of the predisposing factors responsible for the formation of wedge-shaped erosions. Aim: Examination of chemical risk factors as one of the predisposing causes responsible for the formation of wedge-shaped lesions. Method: We examined 62 patients with wedge-shaped erosions (mean age 45.52 ± 12.03 years, 58.1% of men and 60 patients without erosions in the control group (mean age 34.40 ± 9.28 years, 60% men . The entire examination was completed by using a questionnaire at the Dental Clinic of the University of Pristina - Kosovska Mitrovica. salivary pH was measured by the pH meter. Results: The results show that the wedge-shaped lesions often occur equally in both men and women. Considerably often it might appear in older people but can also occur in teenagers. Patients with wedge-shaped erosion have increased acidity of saliva, a heightened sense of acid in the mouth and consume a lot more carbonated drinks compared to patients without erosions. Conclusion: Wedge-shaped lesions are more common in people older than 40 years. Taking into account the results obtained in this study it can be concluded that the chemical risk factors truly fall within the predisposing factors that may be responsible for the creation of wedge-shaped erosions.

  6. Assessment of Neutron Contamination Originating from the Presence of Wedge and Block in Photon Beam Radiotherapy.

    Science.gov (United States)

    Bahreyni Toossi, M T; Khajetash, B; Ghorbani, M

    2018-03-01

    One of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment. Objective: In the present study the impact of wedge and block on neutron contamination production is investigated. The evaluations are conducted for a 15 MV Siemens Primus linear accelerator. Simulations were performed using MCNPX Monte Carlo code. 30˚, 45˚ and 60˚ wedges and a cerrobend block with dimensions of 1.5 × 1.5 × 7 cm 3 were simulated. The investigation were performed in the 10 × 10 cm 2 field size at source to surface distance of 100 cm for depth of 0.5, 2, 3 and 4 cm in a water phantom. Neutron dose was calculated using F4 tally with flux to dose conversion factors and F6 tally. Results showed that the presence of wedge increases the neutron contamination when the wedge factor was considered. In addition, 45˚ wedge produced the most amount of neutron contamination. If the block is in the center of the field, the cerrobend block caused less neutron contamination than the open field due to absorption of neutrons and photon attenuation. The results showed that neutron contamination is less in steeper depths. The results for two tallies showed practically equivalent results. Wedge causes neutron contamination hence should be considered in therapeutic protocols in which wedge is used. In terms of clinical aspects, the results of this study show that superficial tissues such as skin will tolerate more neutron contamination than the deep tissues.

  7. Measured Hydrologic Storage Characteristics of Three Major Ice Wedge Polygon Types, Barrow, Alaska

    Science.gov (United States)

    Chamberlain, A. J.; Liljedahl, A.; Wilson, C. J.; Cable, W.; Romanovsky, V. E.

    2014-12-01

    Model simulations have suggested that the hydrologic fluxes and stores of Arctic wetlands are constrained by the micro-topographical features of ice wedge polygons, which are abundant in lowland tundra landscapes. Recently observed changes in ice wedge polygon landscapes - in particular, ice wedge degradation and trough formation - emphasize the need to better understand how differing ice wedge polygon morphologies affect the larger hydrologic system. Here we present three seasons of measured end-of-winter snow accumulation, continuous soil moisture and water table elevations, and repeated frost table mapping. Together, these describe the hydrologic characteristics of three main ice wedge polygon types: low centered polygons with limited trough development (representative of a ~500 year old vegetated drained thaw lake basin), and low- and high-centered polygons with well-defined troughs. Dramatic spatiotemporal variability exists both between polygon types and between the features of an individual polygon (e.g. troughs, centers, rims). Landscape-scale end-of-winter snow water equivalent is similar between polygon types, while the sub-polygon scale distribution of the surface water differs, both as snow and as ponded water. Some sub-polygon features appear buffered against large variations in water levels, while others display periods of prolonged recessions and large responses to rain events. Frost table elevations in general mimic the ground surface topography, but with spatiotemporal variability in thaw rate. The studied thaw seasons represented above long-term average rainfall, and in 2014, record high June precipitation. Differing ice wedge polygon types express dramatically different local hydrology, despite nearly identical climate forcing and landscape-scale snow accumulation, making ice wedge polygons an important component when describing the Arctic water, nutrient and energy system.

  8. Climate adaptation wedges: a case study of premium wine in the western United States

    International Nuclear Information System (INIS)

    Diffenbaugh, Noah S; Ashfaq, Moetasim; White, Michael A; Jones, Gregory V

    2011-01-01

    Design and implementation of effective climate change adaptation activities requires quantitative assessment of the impacts that are likely to occur without adaptation, as well as the fraction of impact that can be avoided through each activity. Here we present a quantitative framework inspired by the greenhouse gas stabilization wedges of Pacala and Socolow. In our proposed framework, the damage avoided by each adaptation activity creates an 'adaptation wedge' relative to the loss that would occur without that adaptation activity. We use premium winegrape suitability in the western United States as an illustrative case study, focusing on the near-term period that covers the years 2000-39. We find that the projected warming over this period results in the loss of suitable winegrape area throughout much of California, including most counties in the high-value North Coast and Central Coast regions. However, in quantifying adaptation wedges for individual high-value counties, we find that a large adaptation wedge can be captured by increasing the severe heat tolerance, including elimination of the 50% loss projected by the end of the 2030-9 period in the North Coast region, and reduction of the projected loss in the Central Coast region from 30% to less than 15%. Increased severe heat tolerance can capture an even larger adaptation wedge in the Pacific Northwest, including conversion of a projected loss of more than 30% in the Columbia Valley region of Washington to a projected gain of more than 150%. We also find that warming projected over the near-term decades has the potential to alter the quality of winegrapes produced in the western US, and we discuss potential actions that could create adaptation wedges given these potential changes in quality. While the present effort represents an initial exploration of one aspect of one industry, the climate adaptation wedge framework could be used to quantitatively evaluate the opportunities and limits of climate adaptation

  9. Laser-based linear and nonlinear guided elastic waves at surfaces (2D) and wedges (1D).

    Science.gov (United States)

    Hess, Peter; Lomonosov, Alexey M; Mayer, Andreas P

    2014-01-01

    The characteristic features and applications of linear and nonlinear guided elastic waves propagating along surfaces (2D) and wedges (1D) are discussed. Laser-based excitation, detection, or contact-free analysis of these guided waves with pump-probe methods are reviewed. Determination of material parameters by broadband surface acoustic waves (SAWs) and other applications in nondestructive evaluation (NDE) are considered. The realization of nonlinear SAWs in the form of solitary waves and as shock waves, used for the determination of the fracture strength, is described. The unique properties of dispersion-free wedge waves (WWs) propagating along homogeneous wedges and of dispersive wedge waves observed in the presence of wedge modifications such as tip truncation or coatings are outlined. Theoretical and experimental results on nonlinear wedge waves in isotropic and anisotropic solids are presented. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Enhanced dynamic wedge and independent monitor unit verification

    International Nuclear Information System (INIS)

    Howlett, S.J.; University of Newcastle, NSW

    2004-01-01

    Full text: Some serious radiation accidents have occurred around the world during the delivery of radiotherapy treatment. The regrettable incident in Panama clearly indicated the need for independent monitor unit (MU) verification. Indeed the International Atomic Energy Agency (IAEA), after investigating the incident, made specific recommendations for radiotherapy centres which included an independent monitor unit check for all treatments. Independent monitor unit verification is practiced in many radiotherapy centres in developed countries around the world. It is mandatory in USA but not yet in Australia. The enhanced dynamic wedge factor (EDWF) presents some significant problems in accurate MU calculation, particularly in the case of non centre of field position (COF). This paper describes development of an independent MU program, concentrating on the implementation of the EDW component. The difficult case of non COF points under the EDW was studied in detail. A survey of Australasian centres regarding the use of independent MU check systems was conducted. The MUCalculator was developed with reference to MU calculations made by Pinnacle 3D RTP system (Philips) for 4MV, 6MV and 18MV X-ray beams from Varian machines used at the Newcastle Mater Misericordiae Hospital (NMMH) in the clinical environment. Ionisation chamber measurements in solid water TM and liquid water were performed based on a published test data set. Published algorithms combined with a depth dependent profile correction were applied in an attempt to match measured data with maximum accuracy. The survey results are presented. Substantial data is presented in tabular form and extensive comparison with published data. Several different methods for calculating EDWF are examined. A small systematic error was detected in the Gibbon equation used for the EDW calculations. Generally, calculations were within +2% of measured values, although some setups exceeded this variation. Results indicate that COF

  11. Distribution of lithium in the Cordilleran Mantle wedge

    Science.gov (United States)

    Shervais, J. W.; Jean, M. M.; Seitz, H. M.

    2015-12-01

    Enriched fluid-mobile element (i.e., B, Li, Be) concentrations in peridotites from the Coast Range ophiolite are compelling evidence that this ophiolite originated in a subduction environment. A new method presented in Shervais and Jean (2012) for modeling the fluid enrichment process, represents the total addition of material to the mantle wedge source region and can be applied to any refractory mantle peridotite that has been modified by melt extraction and/or metasomatism. Although the end-result is attributed to an added flux of aqueous fluid or fluid-rich melt phase derived from the subducting slab, in the range of tens of parts per million - the nature and composition of this fluid could not be constrained. To address fluid(s) origins, we have analyzed Li isotopes in bulk rock peridotite and eclogite, and garnet separates, to identify possible sources, and fluid flow mechanisms and pathways. Bulk rock Li abundances of CRO peridotites (δ7Li = -14.3 to 5.5‰; 1.9-7.5 ppm) are indicative of Li addition and δ7Li-values are lighter than normal upper mantle values. However, Li abundances of clino- and orthopyroxene appear to record different processes operating during the CRO-mantle evolution. Low Li abundances in orthopyroxene (2 ppm) record subsequent interaction with Li-enriched fluids (or melts). The preferential partitioning of lithium in clinopyroxene could be indicative of a particular metasomatic agent, e.g., fluids from a dehydrating slab. Future in-situ peridotite isotope studies via laser ablation will further elucidate the fractionation of lithium between orthopyroxene, clinopyroxene, and serpentine. To obtain a more complete picture of the slab to arc transfer processes, we also measured eclogites and garnet separates to δ7Li= -18 to 3.5‰ (11.5-32.5 ppm) and δ7Li= 1.9 to 11.7‰ (0.7-3.9 ppm), respectively. In connection with previous studies focused on high-grade metamorphic assemblages within the Franciscan complex, an overall framework exists

  12. Metallic wedge degraders for rapid energy measurement of Bevalac heavy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Wada, R.; Alonso, J.R.

    1981-03-01

    An ever-present need in an accelerator-based research program is knowing the energy of the beam delivered to the experimenter. Knowledge of accelerator parameters is generally good enough to predict the beam energy to within a few percent as it leaves the machine, but after passage through a complex switchyard, with air gaps, and non-destructive monitors, substantial changes in the energy can occur. Knowledge of the material in the beam path allows for calculations of expected energy loss, but this knowledge is not always complete, and the unforeseen often plays tricks on the unwary experimenter; for example, a section of beam-pipe inadvertently let up to air, or a monitor left in the beam-line from the previous run. Although such occurrences are rare, to say they do not happen would be grossly inaccurate. The only defense of the experimenter, then, is to have an accurate technique for determining the beam energy at his target location, a technique which requires little beam time and which is non-disruptive of his experimental setup. The device described meets all of these criteria, and is now used extensively in the Nuclear Science and Biomedical programs at the Bevalac.

  13. Metallic wedge degraders for rapid energy measurement of Bevalac heavy ion beams

    International Nuclear Information System (INIS)

    Wada, R.; Alonso, J.R.

    1981-03-01

    An ever-present need in an accelerator-based research program is knowing the energy of the beam delivered to the experimenter. Knowledge of accelerator parameters is generally good enough to predict the beam energy to within a few percent as it leaves the machine, but after passage through a complex switchyard, with air gaps, and non-destructive monitors, substantial changes in the energy can occur. Knowledge of the material in the beam path allows for calculations of expected energy loss, but this knowledge is not always complete, and the unforeseen often plays tricks on the unwary experimenter; for example, a section of beam-pipe inadvertently let up to air, or a monitor left in the beam-line from the previous run. Although such occurrences are rare, to say they do not happen would be grossly inaccurate. The only defense of the experimenter, then, is to have an accurate technique for determining the beam energy at his target location, a technique which requires little beam time and which is non-disruptive of his experimental setup. The device described meets all of these criteria, and is now used extensively in the Nuclear Science and Biomedical programs at the Bevalac

  14. Assessment of an amorphous silicon EPID for quality assurance of enhanced dynamic wedge

    International Nuclear Information System (INIS)

    Greer, P.

    2004-01-01

    Full text: Routine quality assurance (QA) of enhanced dynamic wedge (EDW) is usually performed weekly to monthly. Wedge factors are measured with ion-chamber, and profiles usually with diode-arrays such as the Profiler. The use of an electronic portal imaging device (EPID) for these measurements would combine these into a single rapid set-up and measurement. Currently the Varian EPID in standard imaging mode will not acquire integrated images during EDW treatments, and therefore has not been utilised for EDW dosimetry. Modification to image acquisition was made to enable imaging for EDW, and the performance of the EPID for suitability for quality assurance of EDW was investigated. The accuracy of EDW profiles measured with the EPID were assessed by comparison to Profiler measurements. The EPID was positioned at 105 cm to the detector surface, with 4 cm of additional solid water build-up to give total build-up including EPID inherent build-up of 5 cm. Images of EDW fields were acquired with continuous frame-averaging throughout the delivery. Field sizes of 10x10 cm, and 20x20 cm were used for 30 deg and 60 deg wedge angles for both 6 MV and 18 MV x-rays. Profiler measurements of the same fields were made with 5 cm of solid water build-up with 105 cm to the detector. Profiles in the wedged direction along the central axis of the beam were then compared. The reproducibility of the EPID measured profiles was assessed by three measurements made at weekly intervals. The accuracy of EPID measured wedge factors was investigated with the same experimental set-up. Three images of a 10x10 cm open field were acquired, and the mean pixel value in a 9x9 pixel region at the central axis was found. As the pixel value is the average of all acquired frames, this was multiplied by the number of frames to yield an integrated pixel value. This was repeated for three 10x10 cm 60 deg wedge irradiations. The wedge factor measured with the EPID was then compared to routine weekly

  15. Triangular facets of slope in the region of Tudela (Ebro Basin, Navarra, Spain); Facetas triangulares de ladera en la region de Tudela (Depresion del Ebro, Navarra, Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Marin, C.; Desir, G.; Gutierrez, M.

    2009-07-01

    Some triangular slope facets are localized to the south of Bardenas Reales (central-west of Ebro Basin), elaborated on Tudela Formation deposits, Aragonian in age. Three of them have been dated by OSL resulting on ages of 35,588{+-}2,488 yr. BP, 35,355{+-}2,446 yr. BP and 40.185{+-}2,411 yr. BP. The origin of these facets is ought to an alternation between accumulation and incision phases produced by vegetation cover variation percentage. Those vegetation cover changes are estimated to be due to climatic changes. (Author) 21 refs.

  16. Investigation of turbulent wedges generated by different single surface roughness elements

    Science.gov (United States)

    Traphan, Dominik; Meinlschmidt, Peter; Lutz, Otto; Peinke, Joachim; Gülker, Gerd

    2013-11-01

    It is known that small faults on rotor blades of wind turbines can cause significant power loss. In order to better understand the governing physical effects, in this experimental study, the formation of a turbulent wedge over a flat plate induced by single surface roughness elements is under investigation. The experiments are performed at different ambient pressure gradients, thus allowing conclusions about the formation of a turbulent wedge over an airfoil. With respect to typical initial faults on operating airfoils, the roughness elements are modified in both size and shape (raised or recessed). None intrusive experimental methods, such as stereoscopic PIV and LDA, enable investigations based on temporally and spatially highly resolved velocity measurements. In this way, a spectral analysis of the turbulent boundary layer is performed and differences in coherent structures within the wedge are identified. These findings are correlated with global measurements of the wedge carried out by infrared thermography. This correlation aims to enable distinguishing the cause and main properties of a turbulent wedge by the easy applicable method of infrared thermography, which is of practical relevance in the field of condition monitoring of wind turbines.

  17. Study and evaluation of the Siemens virtual wedge factor: dosimetric monitor system and variable field effects

    Energy Technology Data Exchange (ETDEWEB)

    Sendon Rio, J R Sendon; Martinez, C Otero; GarcIa, M Sanchez; Busto, R Lobato; Vega, V Luna; Sueiro, J Mosquera; Camean, M Pombar [Servizo de Radiofisica e Proteccion Radioloxica, Complexo Hospitalario Universitario de Santiago de Compostela (CHUS), Santiago de Compostela (Spain)], E-mail: jose.ramon.sendon.del.rio@sergas.es

    2008-03-07

    In the year 1997 Siemens introduced the virtual wedge in its accelerators. The idea was that a dose profile similar to that of a physical wedge can be obtained by moving one of the accelerator jaws at a constant speed while the dose rate is changing. This work explores the observed behaviour of virtual wedge factors. A model is suggested which takes into account that at any point in time, when the jaw moves, the dose at a point of interest in the phantom is not only due to the direct beam. It also depends on the scattered radiation in the phantom, the head scatter and the behaviour of the monitoring system of the accelerator. Measurements are performed in a Siemens Primus accelerator and compared to the model predictions. It is shown that the model agrees reasonably well with measurements spanning a wide range of conditions. A strong dependence of virtual wedge factors on the dosimetric board has been confirmed and an explanation has been given on how the balance between different contributions is responsible for virtual wedge factors values.

  18. Characterizing and configuring motorized wedge for a new generation telecobalt machine in a treatment planning system

    Directory of Open Access Journals (Sweden)

    Kinhikar Rajesh

    2007-01-01

    Full Text Available A new generation telecobalt unit, Theratron Equinox-80, (MDS Nordion, Canada has been evaluated. It is equipped with a single 60-degree motorized wedge (MW, four universal wedges (UW for 150, 300, 450 and 600. MW was configured in Eclipse (Varian, Palo Alto, USA 3D treatment planning system (TPS. The profiles and central axis depth doses (CADD were measured with radiation field analyzer blue water phantom for MW. These profiles and CADD for MW were compared with UW in a homogeneous phantom generated in Eclipse for various field sizes. The absolute dose was measured for a field size of 10 x 10 cm2 only in a MEDTEC water phantom at 10 cm depth with a 0.13 cc thimble ion chamber (Scanditronix Wellhofer, Uppsala, Sweden and a NE electrometer (Nuclear Enterprises, UK. Measured dose with ion chamber was compared with the TPS predicted dose. MW angle was verified on the Equinox for four angles (15o, 30o, 45o and 60o. The variation in measured and calculated dose at 10 cm depth was within 2%. The measured and the calculated wedge angles were in well agreement within 2o. The motorized wedges were successfully configured in Eclipse for four wedge angles.

  19. Comparative study on triangular and quadrilateral meshes by a finite-volume method with a central difference scheme

    KAUST Repository

    Yu, Guojun

    2012-10-01

    In this article, comparative studies on computational accuracies and convergence rates of triangular and quadrilateral meshes are carried out in the frame work of the finite-volume method. By theoretical analysis, we conclude that the number of triangular cells needs to be 4/3 times that of quadrilateral cells to obtain similar accuracy. The conclusion is verified by a number of numerical examples. In addition, the convergence rates of the triangular meshes are found to be slower than those of the quadrilateral meshes when the same accuracy is obtained with these two mesh types. © 2012 Taylor and Francis Group, LLC.

  20. Comparative study on triangular and quadrilateral meshes by a finite-volume method with a central difference scheme

    KAUST Repository

    Yu, Guojun; Yu, Bo; Sun, Shuyu; Tao, Wenquan

    2012-01-01

    In this article, comparative studies on computational accuracies and convergence rates of triangular and quadrilateral meshes are carried out in the frame work of the finite-volume method. By theoretical analysis, we conclude that the number of triangular cells needs to be 4/3 times that of quadrilateral cells to obtain similar accuracy. The conclusion is verified by a number of numerical examples. In addition, the convergence rates of the triangular meshes are found to be slower than those of the quadrilateral meshes when the same accuracy is obtained with these two mesh types. © 2012 Taylor and Francis Group, LLC.

  1. A quantum hybrid with a thin antenna at the vertex of a wedge

    Energy Technology Data Exchange (ETDEWEB)

    Carlone, Raffaele, E-mail: raffaele.carlone@unina.it [Università “Federico II” di Napoli, Dipartimento di Matematica e Applicazioni “R. Caccioppoli”, MSA, via Cinthia, I-80126, Napoli (Italy); Posilicano, Andrea, E-mail: andrea.posilicano@uninsubria.it [DiSAT, Università dell' Insubria, via Valleggio 11, I-22100, Como (Italy)

    2017-03-26

    We study the spectrum, resonances and scattering matrix of a quantum Hamiltonian on a “hybrid surface” consisting of a half-line attached by its endpoint to the vertex of a concave planar wedge. At the boundary of the wedge, outside the vertex, homogeneous Dirichlet conditions are imposed. The system is tunable by varying the measure of the angle at the vertex. - Highlights: • Spectral characterization of a quantum Hamiltonian on “hybrid surface” consisting of a halfline attached to the vertex of a concave planar wedge. • The system is tunable by varying the measure of the angle at the vertex. • Relation between the conduction properties inside the hybrid and formation of resonances. • Easy generalization of the results to more complicated structures.

  2. Dispersion analysis and measurement of circular cylindrical wedge-like acoustic waveguides.

    Science.gov (United States)

    Yu, Tai-Ho

    2015-09-01

    This study investigated the propagation of flexural waves along the outer edge of a circular cylindrical wedge, the phase velocities, and the corresponding mode displacements. Thus far, only approximate solutions have been derived because the corresponding boundary-value problems are complex. In this study, dispersion curves were determined using the bi-dimensional finite element method and derived through the separation of variables and the Hamilton principle. Modal displacement calculations clarified that the maximal deformations appeared at the outer edge of the wedge tip. Numerical examples indicated how distinct thin-film materials deposited on the outer surface of the circular cylindrical wedge influenced the dispersion curves. Additionally, dispersion curves were measured using a laser-induced guided wave, a knife-edge measurement scheme, and a two-dimensional fast Fourier transform method. Both the numerical and experimental results correlated closely, thus validating the numerical solution. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Electromagnetic Scattering from a PEC Wedge Capped with Cylindrical Layers with Dielectric and Conductive Properties

    Directory of Open Access Journals (Sweden)

    H. Ozturk

    2017-04-01

    Full Text Available Electromagnetic scattering from a layered capped wedge is studied. The wedge is assumed infinite in z-direction (longitudinal and capped with arbitrary layers of dielectric with varying thicknesses and dielectric properties including conductive loss. Scalar Helmholtz equation in two dimensions is formulated for each solution region and a matrix of unknown coefficients are arrived at for electric field representation. Closed form expressions are derived for 2- and 3-layer geometries. Numerical simulations are performed for different wedge shapes and dielectric layer properties and compared to PEC-only case. It has been shown that significant reduction in scattered electric field can be obtained with 2- and 3-layered cap geometries. Total electric field in the far field normalized to incident field is also computed as a precursor to RCS analysis. Analytical results can be useful in radar cross section analysis for aerial vehicles.

  4. The synthesis and adsorption properties of some carbohydrate-terminated dendrimer wedges

    International Nuclear Information System (INIS)

    Ainsworth, Richard L.

    1997-01-01

    A range of dendritic molecules that are designed to bind to a cotton surface has been synthesised. The architecture of the molecules allows the location of various functional, property modifying units at the focus and the attachment of recognition groups at the periphery of a dendritic molecule with wedge topology. The synthesis and characterisation of dendrimer wedges up to the second generation using a divergent approach has been performed. These wedges are readily built up using a simple and efficient stepwise pathway from the central core, and surface recognising species are subsequently attached to the molecule utilising procedures developed in conjunction with Unilever Research Laboratories. Work has been carried out to assess their adsorption onto a cotton surface and the postulated adsorption mechanism is discussed. (author)

  5. Spacing of Imbricated Thrust Faults and the Strength of Thrust-Belts and Accretionary Wedges

    Science.gov (United States)

    Ito, G.; Regensburger, P. V.; Moore, G. F.

    2017-12-01

    The pattern of imbricated thrust blocks is a prominent characteristic of the large-scale structure of thrust-belts and accretionary wedges around the world. Mechanical models of these systems have a rich history from laboratory analogs, and more recently from computational simulations, most of which, qualitatively reproduce the regular patterns of imbricated thrusts seen in nature. Despite the prevalence of these patterns in nature and in models, our knowledge of what controls the spacing of the thrusts remains immature at best. We tackle this problem using a finite difference, particle-in-cell method that simulates visco-elastic-plastic deformation with a Mohr-Coulomb brittle failure criterion. The model simulates a horizontal base that moves toward a rigid vertical backstop, carrying with it an overlying layer of crust. The crustal layer has a greater frictional strength than the base, is cohesive, and is initially uniform in thickness. As the layer contracts, a series of thrust blocks immerge sequentially and form a wedge having a mean taper consistent with that predicted by a noncohesive, critical Coulomb wedge. The widths of the thrust blocks (or spacing between adjacent thrusts) are greatest at the front of the wedge, tend to decrease with continued contraction, and then tend toward a pseudo-steady, minimum width. Numerous experiments show that the characteristic spacing of thrusts increases with the brittle strength of the wedge material (cohesion + friction) and decreases with increasing basal friction for low (laws that will illuminate the basic physical processes controlling systems, as well as allow researchers to use observations of thrust spacing as an independent constraint on the brittle strength of wedges as well as their bases.

  6. Wedge geometry, frictional properties and interseismic coupling of the Java megathrust

    Science.gov (United States)

    Koulali, Achraf; McClusky, Simon; Cummins, Phil; Tregoning, Paul

    2018-06-01

    The mechanical interaction between rocks at fault zones is a key element for understanding how earthquakes nucleate and propagate. Therefore, estimating frictional properties along fault planes allows us to infer the degree of elastic strain accumulation throughout the seismic cycle. The Java subduction zone is an active plate boundary where high seismic activity has long been documented. However, very little is known about the seismogenic processes of the megathrust, especially its shallowest portion where onshore geodetic networks are insensitive to recover the pattern of elastic strain. Here, we use the geometry of the offshore accretionary prism to infer frictional properties along the Java subduction zone, using Coulomb critical taper theory. We show that large portions of the inner wedge in the eastern part of the Java subduction megathrust are in a critical state, where the wedge is on the verge of failure everywhere. We identify four clusters with an internal coefficient of friction μint of ∼ 0.8 and hydrostatic pore pressure within the wedge. The average effective coefficient of friction ranges between 0.3 and 0.4, reflecting a strong décollement. Our results also show that the aftershock sequence of the 1994 Mw 7.9 earthquake halted adjacent to a critical segment of the wedge, suggesting that critical taper wedge areas in the eastern Java subduction interface may behave as a permanent barrier to large earthquake rupture. In contrast, in western Java topographic slope and slab dip profiles suggest that the wedge is mechanically stable, i.e deformation is restricted to sliding along the décollement, and likely to coincide with a seismogenic portion of the megathrust. We discuss the seismic hazard implications and highlight the importance of considering the segmentation of the Java subduction zone when assessing the seismic hazard of this region.

  7. Application of super-omni wedge concept to conformal radiotherapy treatment planning

    International Nuclear Information System (INIS)

    Dai Jianrong; Fu Weihua; Hu Yimin

    2004-01-01

    Objective: To describe a method which can optimize beam weight, wedge angle, and wedge orientation simultaneously by combining the super-omni wedge (SOW) concept with the function of beam weight optimization provided by a commercial treatment planning system. Methods: A five-step procedure including: Step 1. To set up four 60 degree nominal wedged beams for each beam direction with the wedge orientations of 'LEFT', 'IN', 'RIGHT', 'OUT', respectively; Step 2. To define an optimization request, including an optimization goal and constraints. Authors use CMS Focus treatment planning system which allows us to choose 'maximize target dose' or 'minimize critical structure dose' as the optimization goal, and to set minimum target dose, maximum target dose, and maximum average dose of critical structures as constraints. Then the optimization process was launched as step 3; Step 4. To evaluate the plan using isodose distributions and dose-volume histograms. If acceptable, go to Step 5. Otherwise, go back to Step 2 to modify optimization constraints; and Step 5. Transform the SOW beams into the beams of omni wedge so as to reduce the number of to-be-delivered beams. Results: This procedure was found being able to demonstrate successfully in two clinical cases: an esophageal carcinoma and a brain tumor. Compared with manually designed plan, the optimized plan showed better dose homogeneity in the targets and better sparing of the critical structures. Conclusions: This method described is able to optimize beam weights while working with a treatment planning system. Not only does it improve treatment plans' quality, but also shorten the treatment planning process

  8. Cementless Hip Stem Anteversion in the Dysplastic Hip: A Comparison of Tapered Wedge vs Metaphyseal Filling.

    Science.gov (United States)

    Taniguchi, Naofumi; Jinno, Tetsuya; Koga, Daisuke; Hagino, Tetsuo; Okawa, Atsushi; Haro, Hirotaka

    2017-05-01

    Appropriate stem anteversion is important for achieving stability of the prosthetic joint in total hip arthroplasty. Anteversion of a cementless femoral stem is affected by the femoral canal morphology and varies according to stem geometry. We investigated the difference and variation of the increase in anteversion between 2 types of cementless stems, and the correlation between each stem and the preoperative femoral anteversion. We retrospectively compared 2 groups of hips that underwent total hip arthroplasty using a metaphyseal filling stem (78 hips) or a tapered wedge stem (83 hips). All the patients had osteoarthritis due to hip dysplasia. Computed tomography was used to measure preoperative femoral anteversion at 5 levels and postoperative stem anteversion. The increase in anteversion of the tapered wedge stem group (22.7° ± 11.6°) was more than that of the metaphyseal filling stem group (17.2° ± 8.3°; P = .0007). The variation of the increase in the tapered wedge stem group was significantly larger than that in the metaphyseal filling stem group (P = .0016). The metaphyseal filling stem group was more highly and positively correlated with femoral anteversion than the tapered wedge stem group. Femoral anteversion affects stem anteversion differently according to stem geometry. The tapered wedge stems had greater variation of the increase in anteversion than did the metaphyseal filling stems. Based on the results of this study, it is difficult to preoperatively estimate the increase in stem anteversion for tapered wedge stems. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Edge structures and properties of triangular antidots in single-layer MoS2

    KAUST Repository

    Gan, Li Yong; Cheng, Yingchun; Schwingenschlö gl, Udo; Yao, Yingbang; Zhao, Yong; Zhang, Xixiang; Huang, Wei

    2016-01-01

    Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS2. The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS2 samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS2 devices. Published by AIP Publishing.

  10. Edge structures and properties of triangular antidots in single-layer MoS2

    KAUST Repository

    Gan, Li Yong

    2016-08-30

    Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS2. The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS2 samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS2 devices. Published by AIP Publishing.

  11. A waveless free surface flow past a submerged triangular obstacle in presence of surface tension

    Directory of Open Access Journals (Sweden)

    Hakima Sekhri

    2016-07-01

    Full Text Available We consider the Free surface flows passing a submerged triangular obstacle at the bottom of a channel. The problem is characterized by a nonlinear boundary condition on the surface of unknown configuration. The analytical exact solutions for these problems are not known. Following Dias and Vanden Broeck [6], we computed numerically the solutions via a series truncation method. These solutions depend on two parameters: the Weber number $\\alpha$ characterizing the strength of the surface tension and the angle $\\beta$ at the base characterizing the shape of the apex. Although free surface flows with surface tension admit capillary waves, it is found that solution exist only for values of the Weber number greater than $\\alpha_0$ for different configurations of the triangular obstacle.

  12. Edge structures and properties of triangular antidots in single-layer MoS2

    International Nuclear Information System (INIS)

    Gan, Li-Yong; Cheng, Yingchun; Huang, Wei; Schwingenschlögl, Udo; Yao, Yingbang; Zhao, Yong; Zhang, Xi-xiang

    2016-01-01

    Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS 2 . The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS 2 samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS 2 devices.

  13. Edge structures and properties of triangular antidots in single-layer MoS{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Li-Yong, E-mail: ganly@swjtu.edu.cn, E-mail: iamyccheng@njtech.edu.cn, E-mail: udo.schwingenschlogl@kaust.edu.sa [Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R& D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, Yingchun, E-mail: ganly@swjtu.edu.cn, E-mail: iamyccheng@njtech.edu.cn, E-mail: udo.schwingenschlogl@kaust.edu.sa; Huang, Wei [Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials - SICAM, Nanjing Tech University - NanjingTech, 30 South Puzhu Road, Nanjing 211816 (China); Schwingenschlögl, Udo, E-mail: ganly@swjtu.edu.cn, E-mail: iamyccheng@njtech.edu.cn, E-mail: udo.schwingenschlogl@kaust.edu.sa [Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Yao, Yingbang [Advanced Nanofabrication and Imaging Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); School of Materials and Energy, Guangdong University of Technology, Guangdong 510006 (China); Zhao, Yong [Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R& D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, 610031 Sichuan (China); Zhang, Xi-xiang [Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Advanced Nanofabrication and Imaging Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia)

    2016-08-29

    Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS{sub 2}. The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS{sub 2} samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS{sub 2} devices.

  14. Triangular and honeycomb lattices bond-diluted Ising ferromagnet: critical frontier

    International Nuclear Information System (INIS)

    Magalhaes, A.C.N. de; Schwaccheim, G.; Tsallis, C.

    1982-01-01

    Within a real space renormalization group framework (12 different procedures, all of them using star-triangle and duality-type transformations) accurate approximations for the critical frontiers associated with the quenched bond-diluted first-neighbour spin- 1 / 2 Ising ferromagnet on triangular and honeycomb lattices are calculated. All of them provide, in both pure bond percolation and pure Ising limits, the exact critical points and exact or almost exact derivatives in the p-t space (p is the bond independent occupancy probability and t tanh J/k(sub B)T). The best numerical proposals lead to the exact derivative in the pure percolation limit (p = p(sub c)) and, in what concerns the pure Ising limit (p = 1) derivative, to a 0.15% error for the triangular lattice and to a 0.96% error for the honeycomb one; in the intermediate region (p(sub c) [pt

  15. Chronology and palaeoenvironmental implications of the ice-wedge pseudomorphs and composite-wedge casts on the Magdalen Islands (eastern Canada)

    DEFF Research Database (Denmark)

    Remillard, A.M.; Hetu, B.; Bernatchez, P.

    2015-01-01

    to the former presence of permafrost under periglacial conditions. These features truncate Carboniferous sandstone or Last Glacial Maximum (LGM) glacial and glaciomarine diamicts, both overlain by subtidal or coastal units. Six optically stimulated luminescence (OSL) and four radiocarbon ages were obtained from......The Magdalen Islands are a valuable terrestrial record, evidencing the complex glacial and periglacial history of the Gulf of St. Lawrence. Thirteen structures interpreted as ice-wedge pseudomorphs or composite-wedge casts were observed at four sites on the southern Magdalen Islands and testify...... both host and infilled sedimentary units. These ages provide the first absolute chronological data on these structures, shedding new light on the relationships between glacial and periglacial phases. Our chronostratigraphic data suggest that, after the deglaciation and the emersion of the archipelago...

  16. Contemporary sand wedge development in seasonally frozen ground and paleoenvironmental implications

    Science.gov (United States)

    Wolfe, Stephen A.; Morse, Peter D.; Neudorf, Christina M.; Kokelj, Steven V.; Lian, Olav B.; O'Neill, H. Brendan

    2018-05-01

    Contemporary sand wedges and sand veins are active in seasonally frozen ground within the extensive discontinuous permafrost zone in Northwest Territories, Canada. The region has a subarctic continental climate with 291 mm a-1 precipitation, -4.1 °C mean annual air temperature, warm summers (July mean 17.0 °C), and cold winters (January mean -26.6 °C). Five years of continuous observations indicate that interannual variation of the ground thermal regime is dominantly controlled by winter air temperature and snow cover conditions. At sandy sites, thin snow cover and high thermal conductivity promote rapid freezing, high rates of ground cooling, and low near-surface ground temperatures (-15 to -25 °C), resulting in thermal contraction cracking to depths of 1.2 m. Cracking potentials are high in sandy soils when air temperatures are air temperatures are ≤-17 °C, and snow cover is conditions in peatlands maintain permafrost, but thermal contraction cracking does not occur because thicker snow cover and the thermal properties of peat prolong freezeback and maintain higher winter ground temperatures. A combination of radiocarbon dating, optical dating, and stratigraphic observations were used to differentiate sand wedge types and formation histories. Thermal contraction cracks that develop in the sandy terrain are filled by surface (allochthonous) and/or host (autochthonous) material during the thaw season. Epigenetic sand wedges infilled with allochthonous sand develop within former beach sediments beneath an active eolian sand sheet. Narrower and deeper syngenetic wedges developed within aggrading eolian sand sheets, whereas wider and shallower antisyngenetic wedges developed in areas of active erosion. Thermal contraction cracking beneath vegetation-stabilized surfaces leads to crack infilling by autochthonous host and overlying organic material, with resultant downturning and subsidence of adjacent strata. Sand wedge development in seasonally frozen ground

  17. [Radiocarbon dating of pollen and spores in wedge ice from Iamal and Kolyma].

    Science.gov (United States)

    Vasil'chuk, A K

    2004-01-01

    Radiocarbon dating of pollen concentrate from late Pleistocene syngenetic wedge ice was carried out using acceleration mass spectrometry (AMS) in Seyakha and Bizon sections. Comparison of the obtained dating with palynological analysis and AMS radiocarbon dating previously obtained for other organic fractions of the same samples allowed us to evaluate accuracy of dating of different fractions. Quantitative tests for data evaluation were considered in terms of possible autochthonous or allochthonous accumulation of the material on the basis of pre-Pleistocene pollen content in these samples. Paleoecological information content of pollen spectra from late Pleistocene syngenetic wedge ice was evaluated.

  18. Uniform physical theory of diffraction equivalent edge currents for truncated wedge strips

    DEFF Research Database (Denmark)

    Johansen, Peter Meincke

    1996-01-01

    New uniform closed-form expressions for physical theory of diffraction equivalent edge currents are derived for truncated incremental wedge strips. In contrast to previously reported expressions, the new expressions are well behaved for all directions of incidence and observation and take a finite...... value for zero strip length. This means that the expressions are well suited for implementation in general computer codes. The new expressions are expressed as the difference between two terms. The first term is obtained by integrating the exact fringe wave current on a wedge along an untruncated...

  19. Wedge-shaped parenchymal enhancement peripheral to the hepatic hemangioma : two-phase spiral CT findings

    International Nuclear Information System (INIS)

    Kim, Kyoung Won; Kim, Tae Kyoung; Han, Joon Koo; Kim, Ah Young; Lee, Hyun Ju; Song, Chi Sung; Choi, Byung Ihn

    2000-01-01

    To determine the incidence of hepatic hemangiomas associated with wedge-shaped parenchymal enhancements adjacent to the tumors as seen on two-phase spiral CT images obtained during the hepatic arterial phase and to characterize the two-phase spiral CT findings of those hemangiomas. One hundred and eight consecutive hepatic hemangiomas in 63 patients who underwent two-phase spiral CT scanning during an 11-month period were included in this study. Two-phase spiral CT scans were obtained during the hepatic arterial phase (30-second delay) and portal venous phase (65-second delay) after injection of 120 mL of contrast material at a rate of 3 mL/sec. We evaluated the frequency with which wedge-shaped parenchymal enhancement was adjacent to the hemangiomas during the hepatic arterial phase and divided hemangiomas into two groups according to whether or not wedge-shaped parenchymal enhancement was noted (Group A and Group B). The presence of such enhancement in hemangiomas was correlated with tumor size and the grade of intratumoral enhancement. In 24 of 108 hemangiomas, wedge-shaped parenchymal enhancement adjacent to hepatic tumors was seen on two-phase CT images obtained during the hepatic arterial phase. Mean hemangioma size was 22mm in group A and 24mm in group B. There was no statistically significant relationship between lesion size and the presence of wedge-shaped parenchymal enhancement adjacent to a hemangioma. In 91.7% and 100% of tumors in Group A, and in 9.6% and 17.8% in Group B, hemangiomas showed more than 50% intratumoral enhancement during the arterial and portal venous phase, respectively. Wedge-shaped parenchymal enhancements peripheral to hepatic hemangiomas was more frequently found in tumors showing more than 50% intratumoral enhancement during these two phases (p less than 0.01). Wedge-shaped parenchymal enhancements is not uncommonly seen adjacent to hepatic hemangiomas on two-phase spiral CT images obtained during the hepatic arterial phase. A

  20. Monte Carlo simulation of the Varian Clinac 600C accelerator using dynamic wedges

    International Nuclear Information System (INIS)

    Moreno, S.; Chaves, A.; Lopes, M.C.; Peralta, L.; Universidade de Lisboa

    2004-01-01

    The advent of linear accelerators (linac) with computer-controlled dynamic collimation systems and functional and anatomical imaging techniques allowed a more exact delimitation and localisation of the target volume. These advanced treatment techniques inevitably increase the complexity level of dose calculation because of the introduction of the temporal variable. On account of this, it is mandatory the usage of more accurate modelling techniques of the collimator components, as it is the case of Monte Carlo (MC) simulation, which has created an enormous interest in research and clinical practice. Because the patients bodies are not homogenous nor are their body surfaces plane and regular, the dose distribution may differ significantly from the standard distribution from the linac calibration. It is in the treatment planning systems, which include algorithms that are usually measured in homogeneous water phantoms specific for each correction that the dose distributions from each case are obtained. In a real treatment, exception made to superficial lesions, two or more radiation fields are used in order to obtain the recommended dose distributions. The simplest arrangement is made from two parallel and opposed fields that originate a homogeneous dose distribution in almost all the irradiated volume. The available resources are, for example, different types of energies and of radiation, the application of bolus, the protection of healthy structures, the usage of wedged filters and the application of dynamic wedges. A virtual or dynamic wedge, modelled through the movement of one of the jaws, when compared with a set of physical wedges offers an alternative calculation method of an arbitrary number of wedged fields, instead of the four traditional fields of 15 deg, 30 deg, 45 deg and 60 deg angle and obtained with physical wedges. The goal of this work consists in the study of the application of dynamic wedges in tailoring the radiation field by the Varian Clinac 600

  1. Self-duality for coupled Potts models on the triangular lattice

    International Nuclear Information System (INIS)

    Richard, Jean-Francois; Jacobsen, Jesper Lykke; Picco, Marco

    2004-01-01

    We present self-dual manifolds for coupled Potts models on the triangular lattice. We exploit two different techniques: duality followed by decimation, and mapping to a related loop model. The latter technique is found to be superior, and it allows us to include three-spin couplings. Starting from three coupled models, such couplings are necessary for generating self-dual solutions. A numerical study of the case of two coupled models leads to the identification of novel critical points

  2. Recurrence Relations and Generating Functions of the Sequence of Sums of Corresponding Factorials and Triangular Numbers

    Directory of Open Access Journals (Sweden)

    Romer C. Castillo

    2015-11-01

    Full Text Available This study established some recurrence relations and exponential generating functions of the sequence of factoriangular numbers. A factoriangular number is defined as a sum of corresponding factorial and triangular number. The proofs utilize algebraic manipulations with some known results from calculus, particularly on power series and Maclaurin’s series. The recurrence relations were found by manipulating the formula defining a factoringular number while the ascertained exponential generating functions were in the closed form.

  3. Determination of Constructs and Dimensions of Employability Skills Based Work Performance Prediction: A Triangular Approach

    OpenAIRE

    Rahmat, Normala; Buntat, Yahya; Ayub, Abdul Rahman

    2015-01-01

    The level of the employability skills of the graduates as determined by job role and mapped to the employability skills, which correspond to the requirement of employers, will have significant impact on the graduates’ job performance. The main objective of this study was to identify the constructs and dimensions of employability skills, which can predict the work performance of electronic polytechnic graduate in electrical and electronics industry. A triangular qualitative approach was used i...

  4. Solution of the multigroup diffusion equation for two-dimensional triangular regions by finite Fourier transformation

    International Nuclear Information System (INIS)

    Takeshi, Y.; Keisuke, K.

    1983-01-01

    The multigroup neutron diffusion equation for two-dimensional triangular geometry is solved by the finite Fourier transformation method. Using the zero-th-order equation of the integral equation derived by this method, simple algebraic expressions for the flux are derived and solved by the alternating direction implicit method. In sample calculations for a benchmark problem of a fast breeder reactor, it is shown that the present method gives good results with fewer mesh points than the usual finite difference method

  5. Development of internal transport barrier scenarios at ITER-relevant high triangularity in Jet

    Energy Technology Data Exchange (ETDEWEB)

    Rimini, F.G.; Becoulet, M.; Ekedahl, A.; Huysmans, G.; Joffrin, E.; Litaudon, X. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Giovannozzi, E.; Tudisco, O.; Crisanti, F. [Association Euratol/ENEA/CNR sulla Fusione, Frascali, Rome (Italy); Lomas, P.J.; Alper, B.; Hawkes, N.; Parail, V.; Zastrow, K.D. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Baar, M. de; Vries, P. de [Association Euratom-Fom, TEC Cluster, Nieuwegein (Netherlands); La Luna, E. de [Association Euratom-Ciemat, Madrid (Spain); Saibene, G. [EFDA CSU, Garching (Germany)

    2004-07-01

    The development of ITB s(Internal Transport Barrier) scenarios in high triangularity discharges is of particular interest for ITER advanced tokamak operation. Previous JET experiments have shown that high triangularity favours ELM (Edge Localized Mode)-Free or type I ELMs, which inhibit long lasting ITBs. The recent experiments reported here concentrate on integrated optimisation of edge and core conditions. Edge pedestal was controlled using gas injection, Deuterium or light impurities, and plasma current ramps. Both methods yield more ITB-friendly edge pedestal conditions, varying from small type I to type III ELMs and, in extreme cases, to L-mode edge. In parallel, the conditions for triggering and sustaining a wide ITB were optimised. This plasmas have deeply reversed target current profiles with g{sub min} 3. A narrow inner ITB, located in the reversed shear region, is routinely observed. Large radius ITBs are only triggered when the input power exceeds 20-22 MW, but they do not usually survive the transition into H-mode. The best results, in terms of sustained high performance, have been obtained with Neon injection: a wide ITB is triggered during the phase with L-mode edge and survives into H-mode for about 2 s at H{sub 89}{beta}{sub N} {approx} 3.5 and {approx} 60% of the Greenwald density limit. In summary, a high triangularity scenario has been developed, which combines the desirable I characteristics of controlled edge, long lasting wide ITBs and high performance at density higher than the low triangularity JET scenarios. (authors)

  6. A Systematic Review of Outcomes after Arthroscopic Débridement for Triangular Fibrocartilage Complex Tear.

    Science.gov (United States)

    Saito, Taichi; Malay, Sunitha; Chung, Kevin C

    2017-11-01

    Evidence regarding the effectiveness of arthroscopic débridement for a triangular fibrocartilage complex tear is uncertain. The purpose of this study was to conduct a systematic review of outcomes to evaluate the effectiveness of débridement for triangular fibrocartilage complex tears. The authors searched all available literature in the PubMed, Embase, and MEDLINE (Ovid) databases for articles reporting on triangular fibrocartilage complex tear débridement. Data collection included arc of motion, grip strength, patient-reported outcomes, and complications. A total of 1723 unique studies were identified, of which 18 studies met the authors' criteria. The mean before and after arc of wrist extension/flexion motion values were 120 and 146 degrees (six studies). The mean before and after grip strength values were 65 percent and 91 percent of the contralateral side (10 studies). Disabilities of the Arm, Shoulder, and Hand scores (six studies) and pain visual analogue scale scores (seven studies) improved from 39 to 18, and from 7 to 3, respectively. The mean pain visual analogue scale score after débridement was 1.9 in the ulnar-positive group and 2.4 in the ulnar-neutral and ulnar-negative groups. Eighty-seven percent of patients returned to their original work. Patients reported reduced pain and improved functional and patient-reported outcomes after débridement of triangular fibrocartilage complex tears. Most patients after débridement returned to previous work, with few complications. Although some of these cases may require secondary procedures, simple débridement can be performed with suitable satisfactory outcomes for cases with any type of ulnar variance.

  7. Ganglion Cyst Associated with Triangular Fibrocartilage Complex Tear That Caused Ulnar Nerve Compression

    Directory of Open Access Journals (Sweden)

    Ugur Anil Bingol, MD

    2015-03-01

    Full Text Available Summary: Ganglions are the most frequently seen soft-tissue tumors in the hand. Nerve compression due to ganglion cysts at the wrist is rare. We report 2 ganglion cysts arising from triangular fibrocartilage complex, one of which caused ulnar nerve compression proximal to the Guyonʼs canal, leading to ulnar neuropathy. Ganglion cysts seem unimportant, and many surgeons refrain from performing a general hand examination.

  8. Hofstadter's butterfly energy spectrum of ultracold fermions on the two-dimensional triangular optical lattice

    International Nuclear Information System (INIS)

    Hou Jingmin; Lu Qingqing

    2009-01-01

    We study the energy spectrum of ultracold fermionic atoms on the two-dimensional triangular optical lattice subjected to a perpendicular effective magnetic field, which can be realized with laser beams. We derive the generalized Harper's equations and numerically solve them, then we obtain the Hofstadter's butterfly-like energy spectrum, which has a novel fractal structure. The observability of the Hofstadter's butterfly spectrum is also discussed

  9. Performance improvement of InGaN/GaN light-emitting diodes with triangular- shaped multiple quantum wells

    International Nuclear Information System (INIS)

    Zhu, Li-Hong; Zheng, Qing-Hong; Liu, Bao-Lin

    2009-01-01

    Triangular-shaped InGaN/GaN multiple quantum wells (MQWs) grown on a sapphire substrate were adopted as an active layer of light-emitting diodes (LEDs). The temperature dependence of the normalized integrated photoluminescence (PL) intensity showed that the internal quantum efficiency (IQE) of the LEDs with triangular-shaped MQW is much higher than that of the LEDs with conventional rectangular MQW structures. The electroluminescence (EL) spectra of the two series devices have been comparatively studied as functions of injection current. It was found that the device with the triangular-shaped MQW structure exhibited a stronger intensity and a narrower linewidth. Furthermore, the peak energy is nearly independent of the injection current, indicating that the triangular MQW LEDs are more efficient and stable than the rectangular ones

  10. A Ranking Analysis/An Interlinking Approach of New Triangular Fuzzy Cognitive Maps and Combined Effective Time Dependent Matrix

    Science.gov (United States)

    Adiga, Shreemathi; Saraswathi, A.; Praveen Prakash, A.

    2018-04-01

    This paper aims an interlinking approach of new Triangular Fuzzy Cognitive Maps (TrFCM) and Combined Effective Time Dependent (CETD) matrix to find the ranking of the problems of Transgenders. Section one begins with an introduction that briefly describes the scope of Triangular Fuzzy Cognitive Maps (TrFCM) and CETD Matrix. Section two provides the process of causes of problems faced by Transgenders using Fuzzy Triangular Fuzzy Cognitive Maps (TrFCM) method and performs the calculations using the collected data among the Transgender. In Section 3, the reasons for the main causes for the problems of the Transgenders. Section 4 describes the Charles Spearmans coefficients of rank correlation method by interlinking of Triangular Fuzzy Cognitive Maps (TrFCM) Method and CETD Matrix. Section 5 shows the results based on our study.

  11. Elementary dispersion analysis of some mimetic discretizations on triangular C-grids

    Energy Technology Data Exchange (ETDEWEB)

    Korn, P., E-mail: peter.korn@mpimet.mpg.de [Max Planck Institute for Meteorology, Hamburg (Germany); Danilov, S. [Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany); A.M. Obukhov Institute of Atmospheric Physics, Moscow (Russian Federation)

    2017-02-01

    Spurious modes supported by triangular C-grids limit their application for modeling large-scale atmospheric and oceanic flows. Their behavior can be modified within a mimetic approach that generalizes the scalar product underlying the triangular C-grid discretization. The mimetic approach provides a discrete continuity equation which operates on an averaged combination of normal edge velocities instead of normal edge velocities proper. An elementary analysis of the wave dispersion of the new discretization for Poincaré, Rossby and Kelvin waves shows that, although spurious Poincaré modes are preserved, their frequency tends to zero in the limit of small wavenumbers, which removes the divergence noise in this limit. However, the frequencies of spurious and physical modes become close on shorter scales indicating that spurious modes can be excited unless high-frequency short-scale motions are effectively filtered in numerical codes. We argue that filtering by viscous dissipation is more efficient in the mimetic approach than in the standard C-grid discretization. Lumping of mass matrices appearing with the velocity time derivative in the mimetic discretization only slightly reduces the accuracy of the wave dispersion and can be used in practice. Thus, the mimetic approach cures some difficulties of the traditional triangular C-grid discretization but may still need appropriately tuned viscosity to filter small scales and high frequencies in solutions of full primitive equations when these are excited by nonlinear dynamics.

  12. Tunable multi-wavelength polymer laser based on a triangular-lattice photonic crystal structure

    International Nuclear Information System (INIS)

    Huang, Wenbin; Pu, Donglin; Qiao, Wen; Wan, Wenqiang; Liu, Yanhua; Ye, Yan; Wu, Shaolong; Chen, Linsen

    2016-01-01

    A continuously tunable multi-wavelength polymer laser based on a triangular-lattice photonic crystal cavity is demonstrated. The triangular-lattice resonator was initially fabricated through multiple interference exposure and was then replicated into a low refractive index polymer via UV-nanoimprinting. The blend of a blue-emitting conjugated polymer and a red-emitting one was used as the gain medium. Three periods in the scalene triangular-lattice structure yield stable tri-wavelength laser emission (625.5 nm, 617.4 nm and 614.3 nm) in six different directions. A uniformly aligned liquid crystal (LC) layer was incorporated into the cavity as the top cladding layer. Upon heating, the orientation of LC molecules and thus the effective refractive index of the lasing mode changes which continuously shifts the lasing wavelength. A maximum tuning range of 12.2 nm was observed for the lasing mode at 625.5 nm. This tunable tri-wavelength polymer laser is simple constructed and cost-effective. It may find application in the fields of biosensors and photonic integrated circuits. (paper)

  13. Flat plate film cooling at the coolant supply into triangular and cylindrical craters

    Directory of Open Access Journals (Sweden)

    Khalatov Artem A.

    2017-01-01

    Full Text Available The results are given of the film cooling numerical simulation of three different schemes including single-array of the traditional round inclined holes, as well as inclined holes arranged in the cylindrical or triangular dimples (craters. The results of simulation showed that at the medium and high values of the blowing ratio (m > 1.0 the scheme with coolant supply into triangular craters improves the adiabatic film cooling efficiency by 1.5…2.7 times compared to the traditional array of inclined holes, or by 1.3…1.8 times compared to the scheme with coolant supply into cylindrical craters. The greater film cooling efficiency with the coolant supply into triangular craters is explained by decrease in the intensity of secondary vortex structures (“kidney” vortex. This is due to the partial destruction and transformation of the coolant jets structure interacting with front wall of the crater. Simultaneously, the film cooling uniformity is increased in the span-wise direction.

  14. Pulsating Different Curves of Zero Velocity around Triangular Equilibrium Points in Elliptical Restricted Three-Body Problem

    Directory of Open Access Journals (Sweden)

    A. Narayan

    2013-01-01

    Full Text Available The oblateness and the photogravitational effects of both the primaries on the location and the stability of the triangular equilibrium points in the elliptical restricted three-body problem have been discussed. The stability of the triangular points under the photogravitational and oblateness effects of both the primaries around the binary systems Achird, Lyeten, Alpha Cen-AB, Kruger 60, and Xi-Bootis, has been studied using simulation techniques by drawing different curves of zero velocity.

  15. On the critical point of the fully-anisotropic quenched bond-random Potts ferromagnet in triangular and honeycomb lattices

    International Nuclear Information System (INIS)

    Tsallis, C.; Santos, R.J.V. dos

    1983-01-01

    On conjectural grounds an equation that provides a very good approximation for the critical temperature of the fully-anisotropic homogeneous quenched bond-random q-state Potts ferromagnet in triangular and honeycomb lattices is presented. Almost all the exact particular results presently known for the square, triangular and honeycomb lattices are recovered; the numerical discrepancy is quite small for the few exceptions. Some predictions that we believe to be exact are made explicite as well. (Author) [pt

  16. Evaluation of off-axis wedge correction factor using diode dosimeters for estimation of delivered dose in external radiotherapy

    International Nuclear Information System (INIS)

    Allahverdi, Mahmoud; Shirazi, Alireza; Geraily, Ghazale; Mohammadkarim, Alireza; Esfehani, Mahbod; Nedaie, Hasanali

    2012-01-01

    An in vivo dosimetry system, using p-type diode dosimeters, was characterized for clinical applications of treatment machines ranging in megavoltage energies. This paper investigates two different models of diodes for externally wedged beams and explains a new algorithm for the calculation of the target dose at various tissue depths in external radiotherapy. The values of off-axis wedge correction factors were determined at two different positions in the wedged (toward the thick and thin edges) and in the non-wedged directions on entrance and exit surfaces of a polystyrene phantom in 60 Co and 6 MV photon beams. Depth transmission was defined on the entrance and exit surfaces to obtain the off-axis wedge correction factor at any depth. As the sensitivity of the diodes depends on physical characteristics (field size, source-skin distance (SSD), thickness, backscatter), correction factors were applied to the diode reading when measuring conditions different from calibration situations. The results indicate that needful correction factors for 60 Co wedged photons are usually larger than those for 6 MV wedged photon beams. In vivo dosimetry performed with the proposed algorithms at externally wedged beams has negligible probable errors (less than 0.5%) and is a reliable method for patient dose control. (author)

  17. The effect of shoe design and lateral wedges on knee load and neuromuscular control in healthy subjects during walking

    DEFF Research Database (Denmark)

    Mølgaard, Carsten Møller; Kersting, Uwe G.

    2013-01-01

    and second peak knee adduction moments. However, the variability of this moment between shoe designs was of similar magnitude as the effect of laterally wedged insoles. Only marginal changes in muscle activity for gastrocnemius when walking with the wedged Oxford shoe were revealed. Conclusion: Lateral...

  18. Evaluation of off-axis wedge correction factor using diode dosimeters for estimation of delivered dose in external radiotherapy

    Directory of Open Access Journals (Sweden)

    Mahmoud Allahverdi

    2012-01-01

    Full Text Available An in vivo dosimetry system, using p-type diode dosimeters, was characterized for clinical applications of treatment machines ranging in megavoltage energies. This paper investigates two different models of diodes for externally wedged beams and explains a new algorithm for the calculation of the target dose at various tissue depths in external radiotherapy. The values of off-axis wedge correction factors were determined at two different positions in the wedged (toward the thick and thin edges and in the non-wedged directions on entrance and exit surfaces of a polystyrene phantom in 60 Co and 6 MV photon beams. Depth transmission was defined on the entrance and exit surfaces to obtain the off-axis wedge correction factor at any depth. As the sensitivity of the diodes depends on physical characteristics [field size, source-skin distance (SSD, thickness, backscatter], correction factors were applied to the diode reading when measuring conditions different from calibration situations . The results indicate that needful correction factors for 60 Co wedged photons are usually larger than those for 6 MV wedged photon beams. In vivo dosimetry performed with the proposed algorithms at externally wedged beams has negligible probable errors (less than 0.5% and is a reliable method for patient dose control.

  19. Surgical quality of wedge resection affects overall survival in patients with early stage non-small cell lung cancer.

    Science.gov (United States)

    Ajmani, Gaurav S; Wang, Chi-Hsiung; Kim, Ki Wan; Howington, John A; Krantz, Seth B

    2018-07-01

    Very few studies have examined the quality of wedge resection in patients with non-small cell lung cancer. Using the National Cancer Database, we evaluated whether the quality of wedge resection affects overall survival in patients with early disease and how these outcomes compare with those of patients who receive stereotactic radiation. We identified 14,328 patients with cT1 to T2, N0, M0 disease treated with wedge resection (n = 10,032) or stereotactic radiation (n = 4296) from 2005 to 2013 and developed a subsample of propensity-matched wedge and radiation patients. Wedge quality was grouped as high (negative margins, >5 nodes), average (negative margins, ≤5 nodes), and poor (positive margins). Overall survival was compared between patients who received wedge resection of different quality and those who received radiation, adjusting for demographic and clinical variables. Among patients who underwent wedge resection, 94.6% had negative margins, 44.3% had 0 nodes examined, 17.1% had >5 examined, and 3.0% were nodally upstaged; 16.7% received a high-quality wedge, which was associated with a lower risk of death compared with average-quality resection (adjusted hazard ratio [aHR], 0.74; 95% confidence interval [CI], 0.67-0.82). Compared with stereotactic radiation, wedge patients with negative margins had significantly reduced hazard of death (>5 nodes: aHR, 0.50; 95% CI, 0.43-0.58; ≤5 nodes: aHR, 0.65; 95% CI, 0.60-0.70). There was no significant survival difference between margin-positive wedge and radiation. Lymph nodes examined and margins obtained are important quality metrics in wedge resection. A high-quality wedge appears to confer a significant survival advantage over lower-quality wedge and stereotactic radiation. A margin-positive wedge appears to offer no benefit compared with radiation. Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  20. Impingement of water droplets on wedges and diamond airfoils at supersonic speeds

    Science.gov (United States)

    Serafini, John S

    1953-01-01

    An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves. The results presented include the following conditions: droplet diameters from 2 to 100 microns, pressure altitudes from sea level to 30,000 feet, free-stream static temperatures from 420 degrees to 460 degrees R. Also, free-stream Mach numbers from 1.1 to 2.0, semi-apex angles for the wedge from 1.14 degrees to 7.97 degrees, thickness-to-chord ratios for the diamond airfoil from 0.02 to 0.14, chord lengths from 1 to 20 feet, and angles of attack from zero to the inverse tangent of the airfoil thickness-to-chord ratio.

  1. Optical necklaces generated by the diffraction on a stack of dielectric wedges

    Energy Technology Data Exchange (ETDEWEB)

    Izdebskaya, Yana [Nonlinear Physics Centre, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia); Department of Physics, V.I. Vernandsky Taurida National University, Simferopol 95007, Crimea (Ukraine)], E-mail: yvi124@rsphysse.anu.edu.au

    2008-05-19

    We demonstrate that the regular ring-shaped arrays of Gaussian beams, or optical necklaces, can be generated using diffraction on a stack of dielectric wedges. A condition for self-similarity and structural stability of the beams has been derived and shows good comparison with experimental data.

  2. Numerical Simulation and Experimental Validation of an Integrated Sleeve-Wedge Anchorage for CFRP Rods

    DEFF Research Database (Denmark)

    Schmidt, Jacob Wittrup; Smith, Scott T.; Täljsten, Björn

    2011-01-01

    . Recently, an integrated sleeve-wedge anchorage has been successfully developed specifically for CFRP rods. This paper in turn presents a numerical simulation of the newly developed anchorage using ABAQUS. The three-dimensional finite element (FE) model, which considers material non-linearity, uses...

  3. Slamming pressures on the bottom of a free-falling vertical wedge

    Science.gov (United States)

    Ikeda, C. M.; Judge, C. Q.

    2013-11-01

    High-speed planing boats are subjected to repeat impacts due to slamming, which can cause structural damage and injury to passengers. A first step in understanding and predicting the physics of a craft re-entering the water after becoming partially airborne is an experimental vertical drop test of a prismastic wedge (deadrise angle, β =20° beam, B = 300 mm; and length, L = 600 mm). The acrylic wedge was mounted to a rig allowing it to free-fall into a deep-water tank (5.2m × 5.2m × 4.2m deep) from heights 0 camera (1000 fps, resolution of 1920 × 1200 pixels) is mounted above the wedge model to record the wetted surface as the wedge descended below the free surface. The pressure measurements taken with both conventional surface pressure transducers and the pressure mapping system agree within 10% of the peak pressure values (0.7 bar, typical). Supported by the Office of Naval Research.

  4. Forearc Basin Stratigraphy and Interactions With Accretionary Wedge Growth According to the Critical Taper Concept

    Science.gov (United States)

    Noda, Atsushi

    2018-03-01

    Forearc basins are important constituents of sediment traps along subduction zones; the basin stratigraphy records various events that the basin experienced. Although the linkage between basin formation and accretionary wedge growth suggests that mass balance exerts a key control on their evolution, the interaction processes between basin and basement remain poorly understood. This study performed 2-D numerical simulations in which basin stratigraphy was controlled by changes in sediment fluxes with accretionary wedge growth according to the critical taper concept. The resultant stratigraphy depended on the degree of filling (i.e., whether the basin was underfilled or overfilled) and the volume balance between the sediment flux supplied to the basin from the hinterland and the accommodation space in the basin. The trenchward progradation of deposition with onlapping contacts on the trenchside basin floor occurred during the underfilled phase, which formed a wedge-shaped sedimentary unit. In contrast, the landward migration of the depocenter, with the tilting of strata, was characteristic for the overfilled phase. Condensed sections marked stratigraphic boundaries, indicating when sediment supply or accommodation space was limited. The accommodation-limited intervals could have formed during the end of wedge uplift or when the taper angle decreased and possibly associated with the development of submarine canyons as conduits for bypassing sediments from the hinterland. Variations in sediment fluxes and their balance exerted a strong influence on the stratigraphic patterns in forearc basins. Assessing basin stratigraphy could be a key to evaluating how subduction zones evolve through their interactions with changing surface processes.

  5. Radiographic Outcomes Following Lateral Column Lengthening With a Porous Titanium Wedge.

    Science.gov (United States)

    Gross, Christopher E; Huh, Jeannie; Gray, Joni; Demetracopoulos, Constantine; Nunley, James A

    2015-08-01

    Lateral column lengthening (LCL) is commonly utilized in treating stage II posterior tibialis tendon dysfunction. This study aimed to analyze the outcomes of LCL with porous titanium wedges compared to historic controls of iliac crest autograft and allograft. We hypothesized that the use of a porous titanium wedge would have radiographic improvement and union rates similar to those with the use of autograft and allograft in LCL. Between May 2009 and May 2014, 28 feet in 26 patients were treated with LCL using a porous titanium wedge. Of the 26 patients, 9 were males (34.6%). The average age for males was 43 years (range, 17.9-58.7), 48.7 years (range, 21-72.3) for females. Mean follow-up was 14.6 months. Radiographs were examined for correction of the flatfoot deformity and forefoot abduction. All complications were noted. Radiographically, the patients had a significant deformity correction in the anteroposterior talo-first metatarsal angle, talonavicular coverage angle, lateral talo-first metatarsal angle, and calcaneal pitch. All but 1 patient (96%) had bony incorporation of the porous titanium wedge. The average preoperative visual analog scale pain score was 5; all patients but 3 (12%) had improvements in their pain score, with a mean change of 3.4. LCL with porous titanium had low nonunion rates, improved radiographic correction, and pain relief. Level IV, case series. © The Author(s) 2015.

  6. Dissolved organic carbon loss from Yedoma permafrost amplified by ice wedge thaw

    NARCIS (Netherlands)

    Vonk, J.E.; Mann, P.J.; Dowdy, K.L.; Davydova, A.; Davydov, S.P.; Zimov, N.; Spencer, R.G.M.; Bulygina, E.B.; Eglinton, T.I.; Holmes, R.M.

    2013-01-01

    Pleistocene Yedoma permafrost contains nearly a third of all organic matter (OM) stored in circum-arctic permafrost and is characterized by the presence of massive ice wedges. Due to its rapid formation by sediment accumulation and subsequent frozen storage, Yedoma OM is relatively well preserved

  7. Comparison between dose calculation in XiO® and dosimetric measurements in virtual wedge photon beams

    International Nuclear Information System (INIS)

    Almeida, Laila G.; Amaral, Leonardo L.; Oliveira, Harley F.; Maia, Ana F.

    2012-01-01

    The virtual wedge is useful tool in the radiation treatment planning since it has series of advantages over the hard wedge. Quality control tests ensure correct performance of the planning done in treatment planning systems (TPS). This study aimed to compare doses calculated by TPS and doses measured by ionization chamber (CI) and an ionization chambers array in virtual wedge photon beams of 6 MV. Measures carried out in Primus linear accelerator with a solid water phantom and dosimeter positioned at 10 cm depth with gantry at 0° in many fields sizes and angles in the virtual wedge. Measurements on the central axis used as dosimeter an IC and on off-axis used an IC array. The simulation in CMS-XiO used the CT images of the phantom in the same configuration of the irradiation. Maximum and minimum values of the percentage differences between the doses provided by TPS and measurements with ionization chamber on the central axis were 1.43 and -0.10%, respectively, with average percentage difference of 0.08% and confidence limit of Δ=1.72%. In the region off-axis, the average percentage difference was 0.04%, with a maximum of 1.9%, minimum of 0% and confidence limit of Δ=1.91%. All values for dose percentage differences were below 2% and lower confidence limit of 3% are thus, according to the recommendations of the Technical Report Series - TRS-430. (author)

  8. A Novel Continuous Extrusion Process to Fabricate Wedge-Shaped Light Guide Plates

    Directory of Open Access Journals (Sweden)

    Wen-Tse Hsiao

    2013-01-01

    Full Text Available Backlight modules are key components in thin-film transistor liquid crystal displays (TFT-LCD. Among the components of a backlight module, the light guide plate (LGP plays the most important role controlling the light projected to the eyes of users. A wedge-shaped LGP, with its asymmetrical structure, is usually fabricated by an injection proces, but the fabrication time of this process is long. This study proposes a continuous extrusion process to fabricate wedge-shaped LGPs. This continuous process has advantages for mass production. Besides a T-die and rollers, this system also has an in situ monitor of the melt-bank that forms during the extrusion process, helping control the plate thickness. Results show that the melt bank has a close relationship with the plate thickness. The temperature of the bottom heater and roller was adjusted to reduce the surface deformation of the wedge-shaped plate. This continuous extrusion system can successfully manufacture wedge-shaped LGPs for mass production.

  9. On the role of lateral waves in the radiation from the dielectric wedge

    DEFF Research Database (Denmark)

    Balling, Peter

    1973-01-01

    The field on the dielectric wedge is approximated by a plane-wave expansion as in [1]. Contributions from this solution to both the surface field and the radiation field are examined. Finally, an experimental radiation field is compared with the plane-wave solution and with a geometric-optical...

  10. Wedge Splitting Test on Fracture Behaviour of Fiber Reinforced and Regular High Performance Concretes

    DEFF Research Database (Denmark)

    Hodicky, Kamil; Hulin, Thomas; Schmidt, Jacob Wittrup

    2013-01-01

    The fracture behaviour of three fiber reinforced and regular High Performance Concretes (HPC) is presented in this paper. Two mixes are based on optimization of HPC whereas the third mix was a commercial mix developed by CONTEC ApS (Denmark). The wedge splitting test setup with 48 cubical specimens...

  11. Combining valgus knee brace and lateral foot wedges reduces external forces and moments in osteoarthritis patients

    NARCIS (Netherlands)

    Jafarnezhadgero, Amir Ali; Oliveira, Anderson S.; Mousavi, Seyed Hamed; Madadi-Shad, Morteza

    Osteoarthritis progression can be related to the external knee adduction and flexion moments during walking. Lateral foot wedges and knee braces have been used as treatment for osteoarthritis, but little is known about their influence on knee joint moments generated in the sagittal and frontal

  12. Climate adaptation wedges: a case study of premium wine in the western United States

    Energy Technology Data Exchange (ETDEWEB)

    Diffenbaugh, Noah [Stanford University; White, Michael A [Utah State University (USU); Jones, Gregory V [Southern Oregon University, Ashland, OR; Ashfaq, Moetasim [ORNL

    2011-01-01

    Design and implementation of effective climate change adaptation activities requires quantitative assessment of the impacts that are likely to occur without adaptation, as well as the fraction of impact that can be avoided through each activity. Here we present a quantitative framework inspired by the greenhouse gas stabilization wedges of Pacala and Socolow. In our proposed framework, the damage avoided by each adaptation activity creates an 'adaptation wedge' relative to the loss that would occur without that adaptation activity. We use premium winegrape suitability in the western United States as an illustrative case study, focusing on the near-term period that covers the years 2000 39. We find that the projected warming over this period results in the loss of suitable winegrape area throughout much of California, including most counties in the high-value North Coast and Central Coast regions. However, in quantifying adaptation wedges for individual high-value counties, we find that a large adaptation wedge can be captured by increasing the severe heat tolerance, including elimination of the 50% loss projected by the end of the 2030 9 period in the North Coast region, and reduction of the projected loss in the Central Coast region from 30% to less than 15%. Increased severe heat tolerance can capture an even larger adaptation wedge in the Pacific Northwest, including conversion of a projected loss of more than 30% in the Columbia Valley region of Washington to a projected gain of more than 150%. We also find that warming projected over the near-term decades has the potential to alter the quality of winegrapes produced in the western US, and we discuss potential actions that could create adaptation wedges given these potential changes in quality. While the present effort represents an initial exploration of one aspect of one industry, the climate adaptation wedge framework could be used to quantitatively evaluate the opportunities and limits of climate

  13. Analysis of Fault Spacing in Thrust-Belt Wedges Using Numerical Modeling

    Science.gov (United States)

    Regensburger, P. V.; Ito, G.

    2017-12-01

    Numerical modeling is invaluable in studying the mechanical processes governing the evolution of geologic features such as thrust-belt wedges. The mechanisms controlling thrust fault spacing in wedges is not well understood. Our numerical model treats the thrust belt as a visco-elastic-plastic continuum and uses a finite-difference, marker-in-cell method to solve for conservation of mass and momentum. From these conservation laws, stress is calculated and Byerlee's law is used to determine the shear stress required for a fault to form. Each model consists of a layer of crust, initially 3-km-thick, carried on top of a basal décollement, which moves at a constant speed towards a rigid backstop. A series of models were run with varied material properties, focusing on the angle of basal friction at the décollement, the angle of friction within the crust, and the cohesion of the crust. We investigate how these properties affected the spacing between thrusts that have the most time-integrated history of slip and therefore have the greatest effect on the large-scale undulations in surface topography. The surface position of these faults, which extend through most of the crustal layer, are identifiable as local maxima in positive curvature of surface topography. Tracking the temporal evolution of faults, we find that thrust blocks are widest when they first form at the front of the wedge and then they tend to contract over time as more crustal material is carried to the wedge. Within each model, thrust blocks form with similar initial widths, but individual thrust blocks develop differently and may approach an asymptotic width over time. The median of thrust block widths across the whole wedge tends to decrease with time. Median fault spacing shows a positive correlation with both wedge cohesion and internal friction. In contrast, median fault spacing exhibits a negative correlation at small angles of basal friction (laws that can be used to predict fault spacing in

  14. Propriedades psicométricas da versão brasileira da escala triangular do amor de sternberg Psychometrics properties ofthe Brazilian version of sternberg's triangular love scale

    Directory of Open Access Journals (Sweden)

    Vicente Cassepp-Borges

    2007-01-01

    Full Text Available A Escala Triangular do Amor de Sternberg (ETAS possui 45 itens relacionados à intimidade, paixão e decisão/compromisso. O objetivo deste estudo foi investigar algumas propriedades psicométricas da ETAS no Brasil. A versão brasileira da ETAS, o Teste da Identificação Familiar (FIT e um questionário sobre o relacionamento foram respondidos por 361 estudantes de três universidades. A análise fatorial da ETAS apontou para uma estrutura com três fatores e elevada consistência interna. Buscando aperfeiçoar o instrumento, o número de itens da escala foi reduzido. A nova análise fatorial indicou que as propriedades psicométricas originais foram mantidas. Foram encontradas correlações positivas entre as medidas de amor e o nível de satisfação com o relacionamento. Os resultados indicam que a versão brasileira da ETAS possui propriedades psicométricas adequadas e satisfatórias.The Sternberg's Triangular Love Scale (STLS has 45 items related to intimacy, passion, and decision/commitment. The objective of this study was to investigate some psychometric properties of the STLS in Brazil. The Brazilian version of STLS, the Test of Family Identification (FIT and a measure of satisfaction in the relationship were completed by 361 students from three universities. The factorial analysis of STLS showed a structure with 3 factors and elevated internal consistency. Seeking to improve the instrument, the number of items of the scale was reduced. The new factorial analysis indicated that the original psychometric properties were maintained. Positive correlations were found between the measurements of love and the level of satisfaction with the relationship. The results indicate that the Brazilian version of ETAS possesses adequate and satisfactory psychometric properties

  15. Talinum triangulare Whole wheat meal fortified with soy flour consumed with Talinum triangulare (gbure) soup glycemic index and the test human subjects' lipid profiles.

    Science.gov (United States)

    Emaleku, Sunday Adeola; Omueti, Olusola D; Emaleku, Godsent Oluwakemi

    2017-08-24

    Cardiovascular diseases (CVDs) and diabetes mellitus (DM) are some of the leading causes of death in the world, and diet has roles in their etiology. This research study therefore investigates the glycemic index (GI) of soy flour fortified whole wheat meal (SFFWWM) consumed with Talinum triangulare (gbure) soup and the effects of the meal on the lipid profiles of the test human subjects. The control human subjects and test human subjects were fed D-glucose (DG) and whole wheat meal (WWM) with Talinum triangulare soup respectively on the first day of the experiment, and SFFWWM with the same soup the next day (for test subjects only) after 10-12h overnight fasting. Blood glucose levels of the subjects were taken before and 2h after meals' consumption at 30min interval and blood samples collected for lipid profiles evaluations. The result of the study showed that; SFFWWM consumed with Talinum trianguilare soup has a non-significant lower GI than WWM consumed with the same soup, but a significant lower GI than DG at (P<0.05). Furthermore, there was no significant difference in lipid profiles of the test human subjects between when they consumed WWM and SFFWWM with the soup however, SFFWWM reduced TC, TG, LDL-C and VDL-C and increased HDL-C and TP than WMM at (P<0.05). In addition, GI is positively correlated with TC, TG, LDL-C and VLDL-C, but is negatively correlated with TP and HDL-C. It can therefore be concluded that; fortifying WWM with soy flour would reduce the risk factors of CVDs and DM, the diseases recently claiming thousands of today. Copyright © 2017 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  16. Three Years of High Resolution Year-Round Monitoring of Ice-Wedge Thermal Contraction Cracking in Svalbard

    Science.gov (United States)

    Christiansen, H. H.

    2006-12-01

    Most likely ice-wedges are the most widespread periglacial landform in lowlands with continuous permafrost. With a changing climate it is important to understand better the geomorphological processes controlling ice- wedge growth and decay, as they might cause large changes to the surface of the landscape, particularly if the active layer thickness increases causing melting of the most ice-rich permafrost top layer. As most settlements on permafrost are located in lowland areas, ice-wedge formation can also influence the infrastructure. Understanding the processes of ice-wedge growth and their thaw transformation into ice-wedge casts are essential when using contemporary ice wedges as analogues of Pleistocene thermal contraction cracking in palaeoenvironmental reconstructions. As ice-wedges are largely controlled by winter conditions, improved understanding of the factors controlling their growth will enable better palaeoclimatic reconstructions both directly from ice-wedges, but also from ice-wedge casts, than just mean winter temperatures. Detailed studies of ice-wedge dynamics, including quantification of movement, have only been done in very few places in the Arctic. In high arctic Svalbard at 78°N climate at sea level locates these islands close to the southern limit of the continuous permafrost zone, with MAAT of as much as -4 to -6°C. However, thermal contraction cracking is demonstrated to be widespread in the Adventdalen study area in Svalbard. The year-round field access from the University Centre in Svalbard, UNIS, has enabled the collection of different continuous or high frequency ice-wedge process monitoring data since 2002 to improve the understanding of the geomorphological activity of this landform. In all the winters the air temperature was below -30°C for shorter or longer periods. During all the winters, the temperature in the top permafrost was below -15°C both in the ice-wedge top for shorter or longer periods. The snow cover was

  17. Proximal Opening Wedge Osteotomy Provides Satisfactory Midterm Results With a Low Complication Rate.

    Science.gov (United States)

    Oravakangas, Rami; Leppilahti, Juhana; Laine, Vesa; Niinimäki, Tuukka

    2016-01-01

    Hallux valgus is one of the most common foot deformities. Proximal opening wedge osteotomy is used for the treatment of moderate and severe hallux valgus with metatarsus primus varus. However, hypermobility of the first tarsometatarsal joint can compromise the results of the operation, and a paucity of midterm results are available regarding proximal open wedge osteotomy surgery. The aim of the present study was to assess the midterm results of proximal open wedge osteotomy in a consecutive series of patients with severe hallux valgus. Thirty-one consecutive adult patients (35 feet) with severe hallux valgus underwent proximal open wedge osteotomy. Twenty patients (35.5%) and 23 feet (34.3%) were available for the final follow-up examination. The mean follow-up duration was 5.8 (range 4.6 to 7.0) years. The radiologic measurements and American Orthopaedic Foot and Ankle Society hallux-metatarsophalangeal-interphalangeal scores were recorded pre- and postoperatively, and subjective questionnaires were completed and foot scan analyses performed at the end of the follow-up period. The mean hallux valgus angle decreased from 38° to 23°, and the mean intermetatarsal angle correction decreased from 17° to 10°. The mean improvement in the American Orthopaedic Foot and Ankle Society hallux metatarsophalangeal-interphalangeal score increased from 52 to 84. Two feet (5.7%) required repeat surgery because of recurrent hallux valgus. No nonunions were identified. Proximal open wedge osteotomy provided satisfactory midterm results in the treatment of severe hallux valgus, with a low complication rate. The potential instability of the first tarsometatarsal joint does not seem to jeopardize the midterm results of the operation. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  18. Linking Serpentinite Geochemistry with Possible Alteration and Evolution of Supra-Subduction Wedge Mantle

    Science.gov (United States)

    Scambelluri, M.; Cannaò, E.; Agostini, S.; Gilio, M.

    2016-12-01

    Serpentinites are able to transport and release volatiles and fluid-mobile elements (FME) found in arc magmas. Constraining the trace element compositions of these rocks and of fluids released by de-serpentinization improves our knowledge of mass transfer from subduction zones to volcanic arcs, and of the role of slab and wedge mantle in this global process. Studies of high-pressure ultramafic rocks exhumed from plate interface settings reveal the fluid/rock interactions atop the slab and the processes that can affect the mantle wedge. Alpine eclogite-facies antigorite serpentinite (Voltri Massif) and fully de-serpentinized meta-peridotite (Cima di Gagnone) are enriched in sediment-derived As, Sb, U, Pb before peak dehydration. Their Sr, Pb and B isotopic compositions are reset during prograde (forearc) interaction with slab fluids. The eclogitic garnet and olivine from the Cima di Gagnone metaperidotite trap primary inclusions of the fluid released during breakdown of antigorite and chlorite. The inclusions display FME enrichments (high Cl, S; variable Cs, Rb, Ba, B, Pb, As, Sb) indicating element release from rocks to fluids during dehydration under subarc conditions. Our studies show that serpentinized mantle rocks from subduction zones sequester FME from slab fluids and convey these components and radiogenic isotopes into the mantle wedge upon dehydration. The geochemical processes revealed by such plate-interface rocks can apply to the supra-subduction mantle. Shallow element release from slabs to mantle wedge, downdrag of this altered mantle and its subsequent (subarc) dehydration transfers crust-derived FMEs to the arc magma sources without the need of concomitant subarc dehydration/melting of metasedimentary slab components. The slab signature detected in arc lavas can thus result from geochemical mixing of sediment, oceanic crust and ultramafic reservoirs into altered wedge-mantle rocks, rather than being attributed to multiple fluids.

  19. The solar photovoltaics wedge: pathways for growth and potential carbon mitigation in the US

    Energy Technology Data Exchange (ETDEWEB)

    Drury, Easan; Denholm, Paul [National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO 80401 (United States); Margolis, Robert M, E-mail: easan.drury@nrel.go [National Renewable Energy Laboratory, 901 D Street SW, Suite 930, Washington, DC 20024 (United States)

    2009-09-15

    The challenge of stabilizing global carbon emissions over the next 50 years has been framed in the context of finding seven 1.0 Gton C/year carbon reduction wedges. Solar photovoltaics (PV) could provide at least one carbon wedge, but will require significant growth in PV manufacturing capacity. The actual amount of installed PV capacity required to reach wedge-level carbon reductions will vary greatly depending on the mix of avoided fuels and the additional emissions from manufacturing PV capacity. In this work, we find that the US could reduce its carbon emissions by 0.25 Gton C/year, equal to the fraction of a global carbon wedge proportional to its current domestic electricity use, by installing 792-811 GW of PV capacity. We evaluate a series of PV growth scenarios and find that wedge-level reductions could be met by increasing PV manufacturing capacity and annual installations by 0.95 GW/year/year each year from 2009 to 2050 or by increasing up to 4 GW/year/year for a period of 4-17 years for early and late growth scenarios. This challenge of increasing PV manufacturing capacity and market demand is significant but not out of line with the recent rapid growth in both the global and US PV industry. We find that the rapid growth in PV manufacturing capacity leads to a short term increase in carbon emissions from the US electric sector. However, this increase is small, contributing less than an additional 0.3% to electric sector emissions for less than 4.5 years, alleviating recent concern regarding carbon emissions from rapid PV growth scenarios.

  20. Triangular Nests!

    Science.gov (United States)

    Powell, R. I.

    2002-01-01

    Shows how integer-sided triangles can be nested, each nest having a single enclosing isosceles triangle. Brings to light what can be seen as a relatively simple generalization of Pythagoras' theorem, a result that should be readily accessible to many secondary school pupils. (Author/KHR)

  1. Differential wedging of vertebral body and intervertebral disc in thoracic and lumbar spine in adolescent idiopathic scoliosis – A cross sectional study in 150 patients

    Directory of Open Access Journals (Sweden)

    Kim Hak-Jun

    2008-08-01

    Full Text Available Abstract Background Hueter-Volkmann's law regarding growth modulation suggests that increased pressure on the end plate of bone retards the growth (Hueter and conversely, reduced pressure accelerates the growth (Volkmann. Literature described the same principle in Rat-tail model. Human spine and its deformity i.e. scoliosis has also same kind of pattern during the growth period which causes wedging in disc or vertebral body. Methods This cross sectional study in 150 patients of adolescent idiopathic scoliosis was done to evaluate vertebral body and disc wedging in scoliosis and to compare the extent of differential wedging of body and disc, in thoracic and lumbar area. We measured wedging of vertebral bodies and discs, along with two adjacent vertebrae and disc, above and below the apex and evaluated them according to severity of curve (curve 30° to find the relationship of vertebral body or disc wedging with scoliosis in thoracic and lumbar spine. We also compared the wedging and rotations of vertebrae. Results In both thoracic and lumbar curves, we found that greater the degree of scoliosis, greater the wedging in both disc and body and the degree of wedging was more at apex supporting the theory of growth retardation in stress concentration area. However, the degree of wedging in vertebral body is more than the disc in thoracic spine while the wedging was more in disc than body in lumbar spine. On comparing the wedging with the rotation, we did not find any significant relationship suggesting that it has no relation with rotation. Conclusion From our study, we can conclude that wedging in disc and body are increasing with progression on scoliosis and maximum at apex; however there is differential wedging of body and disc, in thoracic and lumbar area, that is vertebral body wedging is more profound in thoracic area while disc wedging is more profound in lumbar area which possibly form 'vicious cycle' by asymmetric loading to spine for the

  2. A microcomputer program for energy assessment and aggregation using the triangular probability distribution

    Science.gov (United States)

    Crovelli, R.A.; Balay, R.H.

    1991-01-01

    A general risk-analysis method was developed for petroleum-resource assessment and other applications. The triangular probability distribution is used as a model with an analytic aggregation methodology based on probability theory rather than Monte-Carlo simulation. Among the advantages of the analytic method are its computational speed and flexibility, and the saving of time and cost on a microcomputer. The input into the model consists of a set of components (e.g. geologic provinces) and, for each component, three potential resource estimates: minimum, most likely (mode), and maximum. Assuming a triangular probability distribution, the mean, standard deviation, and seven fractiles (F100, F95, F75, F50, F25, F5, and F0) are computed for each component, where for example, the probability of more than F95 is equal to 0.95. The components are aggregated by combining the means, standard deviations, and respective fractiles under three possible siutations (1) perfect positive correlation, (2) complete independence, and (3) any degree of dependence between these two polar situations. A package of computer programs named the TRIAGG system was written in the Turbo Pascal 4.0 language for performing the analytic probabilistic methodology. The system consists of a program for processing triangular probability distribution assessments and aggregations, and a separate aggregation routine for aggregating aggregations. The user's documentation and program diskette of the TRIAGG system are available from USGS Open File Services. TRIAGG requires an IBM-PC/XT/AT compatible microcomputer with 256kbyte of main memory, MS-DOS 3.1 or later, either two diskette drives or a fixed disk, and a 132 column printer. A graphics adapter and color display are optional. ?? 1991.

  3. Geometric triangular chiral hexagon crystal-like complexes organization in pathological tissues biological collision order.

    Directory of Open Access Journals (Sweden)

    Jairo A Díaz

    Full Text Available The present study describes and documents self-assembly of geometric triangular chiral hexagon crystal like complex organizations (GTCHC in human pathological tissues. The authors have found this architectural geometric expression at macroscopic and microscopic levels mainly in cancer processes. This study is based essentially on macroscopic and histopathologic analyses of 3000 surgical specimens: 2600 inflammatory lesions and 400 malignant tumours. Geometric complexes identified photographically at macroscopic level were located in the gross surgical specimen, and these areas were carefully dissected. Samples were taken to carry out histologic analysis. Based on the hypothesis of a collision genesis mechanism and because it is difficult to carry out an appropriate methodological observation in biological systems, the authors designed a model base on other dynamic systems to obtain indirect information in which a strong white flash wave light discharge, generated by an electronic device, hits over the lines of electrical conductance structured in helicoidal pattern. In their experimental model, the authors were able to reproduce and to predict polarity, chirality, helicoid geometry, triangular and hexagonal clusters through electromagnetic sequential collisions. They determined that similar events among constituents of extracelular matrix which drive and produce piezoelectric activity are responsible for the genesis of GTCHC complexes in pathological tissues. This research suggests that molecular crystals represented by triangular chiral hexagons derived from a collision-attraction event against collagen type I fibrils emerge at microscopic and macroscopic scales presenting a lateral assembly of each side of hypertrophy helicoid fibers, that represent energy flow in cooperative hierarchically chiral electromagnetic interaction in pathological tissues and arises as a geometry of the equilibrium in perturbed biological systems. Further

  4. Enhancement of heat transfer by nanofluids and orientations of the equilateral triangular obstacle

    International Nuclear Information System (INIS)

    Bovand, M.; Rashidi, S.; Esfahani, J.A.

    2015-01-01

    Highlights: • The heat transfer is improved by nanofluids and orientations of the obstacle. • The role of solid volume fraction on the fluid flow and heat transfer is studied. • There is an upward drift in the vortices for the diagonal facing flow. • The maximum value of the average Nusselt number is for the vertex facing flow. - Abstract: This paper simulates the forced convective heat transfer of Al 2 O 3 –water nanofluid over an equilateral triangular obstacle. Computations are performed for different orientations of the triangular obstacle (side, vertex and diagonal facing flows). The ranges of Reynolds number (Re) and solid volume fractions of nanoparticles (φ) are 1 ⩽ Re ⩽ 200 and 0 ⩽ φ ⩽ 0.05, respectively. Two-dimensional unsteady conservation laws of mass, momentum, and energy equations have been solved using finite volume method. The effects of Reynolds number, solid volume fractions of nanoparticles and different orientations of the triangular obstacle on the flow and heat transfer characteristics are investigated in detail. Detailed results are presented for wake length, streamline, vorticity, temperature contours and time averaged Nusselt number. Finally, the value of time averaged Nusselt number has been investigated in three equations using least square method which the effects of solid volume fraction of nanoparticles and Reynolds numbers are taken into account. The calculated results revealed that the maximum effect of nanoparticles on heat transfer rate augmentation is for the side facing flow and the minimum is related to the vertex facing flow. Also, the required Reynolds numbers for wake formation decrease with increase in solid volume fraction

  5. Geometric triangular chiral hexagon crystal-like complexes organization in pathological tissues biological collision order.

    Science.gov (United States)

    Díaz, Jairo A; Jaramillo, Natalia A; Murillo, Mauricio F

    2007-12-12

    The present study describes and documents self-assembly of geometric triangular chiral hexagon crystal like complex organizations (GTCHC) in human pathological tissues. The authors have found this architectural geometric expression at macroscopic and microscopic levels mainly in cancer processes. This study is based essentially on macroscopic and histopathologic analyses of 3000 surgical specimens: 2600 inflammatory lesions and 400 malignant tumours. Geometric complexes identified photographically at macroscopic level were located in the gross surgical specimen, and these areas were carefully dissected. Samples were taken to carry out histologic analysis. Based on the hypothesis of a collision genesis mechanism and because it is difficult to carry out an appropriate methodological observation in biological systems, the authors designed a model base on other dynamic systems to obtain indirect information in which a strong white flash wave light discharge, generated by an electronic device, hits over the lines of electrical conductance structured in helicoidal pattern. In their experimental model, the authors were able to reproduce and to predict polarity, chirality, helicoid geometry, triangular and hexagonal clusters through electromagnetic sequential collisions. They determined that similar events among constituents of extracelular matrix which drive and produce piezoelectric activity are responsible for the genesis of GTCHC complexes in pathological tissues. This research suggests that molecular crystals represented by triangular chiral hexagons derived from a collision-attraction event against collagen type I fibrils emerge at microscopic and macroscopic scales presenting a lateral assembly of each side of hypertrophy helicoid fibers, that represent energy flow in cooperative hierarchically chiral electromagnetic interaction in pathological tissues and arises as a geometry of the equilibrium in perturbed biological systems. Further interdisciplinary studies must

  6. Tuning topological phase transitions in hexagonal photonic lattices made of triangular rods

    Science.gov (United States)

    Chan, Hsun-Chi; Guo, Guang-Yu

    2018-01-01

    In this paper we study topological phases in a two-dimensional photonic crystal with broken time (T ) and parity (P ) symmetries by performing calculations of band structures, Berry curvatures, Chern numbers, edge states, and also numerical simulations of light propagation in the edge modes. Specifically, we consider a hexagonal lattice consisting of triangular gyromagnetic rods. Here the gyromagnetic material breaks T symmetry while the triangular rods break P symmetry. Interestingly, we find that the crystal could host quantum anomalous Hall (QAH) phases with different gap Chern numbers (Cg) including | Cg|>1 as well as quantum valley Hall (QVH) phases with contrasting valley Chern numbers (Cv), depending on the orientation of the triangular rods. Furthermore, phase transitions among these topological phases, such as from QAH to QVH and vice versa, can be engineered by a simple rotation of the rods. Our band theoretical analyses reveal that the Dirac nodes at the K and K' valleys in the momentum space are produced and protected by the mirror symmetry (my) instead of the P symmetry, and they become gapped when either T or my symmetry is broken, resulting in a QAH or QVH phase, respectively. Moreover, a high Chern number (Cg=-2 ) QAH phase is generated by gapping triply degenerate nodal points rather than pairs of Dirac points by breaking T symmetry. Our proposed photonic crystal thus provides a platform for investigating intriguing topological phenomena which may be challenging to realize in electronic systems, and also has promising potentials for device applications in photonics such as reflection-free one-way waveguides and topological photonic circuits.

  7. Experimental investigations on frictional resistance and velocity distribution of rough wall with regularly distributed triangular ribs

    International Nuclear Information System (INIS)

    Motozawa, Masaaki; Ito, Takahiro; Iwamoto, Kaoru; Kawashima, Hideki; Ando, Hirotomo; Senda, Tetsuya; Tsuji, Yoshiyuki; Kawaguchi, Yasuo

    2013-01-01

    Highlights: • Flow over the regularly distributed triangular ribs was investigated. • Simultaneous measurement of flow resistance and velocity profile was performed. • Flow resistance was measured directly and velocity profile was measured by LDV. • Flow resistance was estimated by the information of the velocity field. • Estimated flow resistance has good agreement with the measured flow resistance. -- Abstract: The relationship between the flow resistance of a turbulent flow over triangular ribs regularly distributed on a wall surface and the velocity distribution around the ribs was investigated experimentally. A concentric cylinder device composed of an inner test cylinder and an outer cylinder was employed to measure the flow resistance using the torque of the shaft of the inner cylinder and the velocity distribution of the flow around a rib by laser Doppler velocimetry (LDV) simultaneously. We prepared four inner test cylinders having 4, 8, 12 and 16 triangular ribs on the surface with the same interval between them. Each rib had an isosceles right triangle V-shape and a height of 2 mm. To investigate the relationship between flow resistance and velocity distribution, we estimated the frictional drag and pressure drag acting on the surface of the ribs separately using the velocity distribution. Therefore, we could also estimate the total flow resistance using the velocity distribution. As a result of the experiment, the flow resistance and the attachment point downstream of the rib were shown to depend on the distance between ribs. Moreover, the flow resistance estimated using the velocity distribution had good agreement with the flow resistance measured using the torque of the inner cylinder

  8. Explicit formulation of an anisotropic Allman/DKT 3-node thin triangular flat shell elements

    Science.gov (United States)

    Ertas, A.; Krafcik, J. T.; Ekwaro-Osire, S.

    A simple, explicit formulation of the stiffness matrix for an anisotropic, 3-node, thin triangular, flat shell element in global coordinates is presented. An Allman triangle is used for membrane stiffness. The membrane stiffness matrix is explicitly derived by applying an Allman transformation to a Felippa 6-node linear strain triangle (LST). Bending stiffness is incorporated by the use of a discrete Kirchhoff triangle (DKT) bending triangle. Stiffness terms resulting from anisotropic membrane-bending coupling are included by integrating, in area coordinates, membrane and bending strain-displacement matrices.

  9. Two-party Bell inequalities derived from combinatorics via triangular elimination

    International Nuclear Information System (INIS)

    Avis, David; Imai, Hiroshi; Ito, Tsuyoshi; Sasaki, Yuuya

    2005-01-01

    We establish a relation between the two-party Bell inequalities for two-valued measurements and a high-dimensional convex polytope called the cut polytope in polyhedral combinatorics. Using this relation, we propose a method, triangular elimination, to derive tight Bell inequalities from facets of the cut polytope. This method gives two hundred million inequivalent tight Bell inequalities from currently known results on the cut polytope. In addition, this method gives general formulae which represent families of infinitely many Bell inequalities. These results can be used to examine general properties of Bell inequalities

  10. Voltage-Controlled Square/Triangular Wave Generator with Current Conveyors and Switching Diodes

    Directory of Open Access Journals (Sweden)

    Martin Janecek

    2012-12-01

    Full Text Available A novel relaxation oscillator based on integrating the diode-switched currents and Schmitt trigger is presented. It is derived from a known circuit with operational amplifiers where these active elements were replaced by current conveyors. The circuit employs only grounded resistances and capacitance and is suitable for high frequency square and triangular signal generation. Its frequency can be linearly and accurately controlled by voltage that is applied to a high-impedance input. Computer simulation with a model of a manufactured conveyor prototype verifies theoretic assumptions.

  11. Superconductivity in the Penson-Kolb Model on a Triangular Lattice

    Science.gov (United States)

    Ptok, A.; Mierzejewski, M.

    2008-07-01

    We investigate properties of the two-dimensional Penson-Kolb model with repulsive pair hopping interaction. In the case of a bipartite square lattice this interaction may lead to the η-type pairing, when the phase of superconducting order parameter changes from one lattice site to the neighboring one. We show that this interaction may be responsible for the onset of superconductivity also for a triangular lattice. We discuss the spatial dependence of the superconducting order parameter and demonstrate that the total momentum of the paired electrons is determined by the lattice geometry.

  12. Cost efficiency with triangular fuzzy number input prices: An application of DEA

    International Nuclear Information System (INIS)

    Bagherzadeh Valami, H.

    2009-01-01

    The cost efficiency model (CE) has been considered by researchers as a Data Envelopment Analysis (DEA) model for evaluating the efficiency of DMUs. In this model, the possibility of producing the outputs of a target DMU is evaluated by the input prices of the DMU. This provides a criterion for evaluating the CE of DMUs. The main contribution of this paper is to provide an approach for generalizing the CE of DMUs when their input prices are triangular fuzzy numbers, where preliminary concepts of fuzzy theory and CE, are directly used.

  13. Adaptive Finite Volume Method for the Shallow Water Equations on Triangular Grids

    Directory of Open Access Journals (Sweden)

    Sudi Mungkasi

    2016-01-01

    Full Text Available This paper presents a numerical entropy production (NEP scheme for two-dimensional shallow water equations on unstructured triangular grids. We implement NEP as the error indicator for adaptive mesh refinement or coarsening in solving the shallow water equations using a finite volume method. Numerical simulations show that NEP is successful to be a refinement/coarsening indicator in the adaptive mesh finite volume method, as the method refines the mesh or grids around nonsmooth regions and coarsens them around smooth regions.

  14. The Implementation of Cumulative Learning Theory in Calculating Triangular Prism and Tube Volumes

    Science.gov (United States)

    Muklis, M.; Abidin, C.; Pamungkas, M. D.; Masriyah

    2018-01-01

    This study aims at describing the application of cumulative learning theory in calculating the volume of a triangular prism and a tube as well as revealing the students’ responses toward the learning. The research method used was descriptive qualitative with elementary school students as the subjects of the research. Data obtained through observation, field notes, questionnaire, tests, and interviews. The results from the application of cumulative learning theory obtained positive students’ responses in following the learning and students’ learning outcomes was dominantly above the average. This showed that cumulative learning could be used as a reference to be implemented in learning, so as to improve the students’ achievement.

  15. Statistical thermodynamics of long straight rigid rods on triangular lattices: nematic order and adsorption thermodynamic functions.

    Science.gov (United States)

    Matoz-Fernandez, D A; Linares, D H; Ramirez-Pastor, A J

    2012-09-04

    The statistical thermodynamics of straight rigid rods of length k on triangular lattices was developed on a generalization in the spirit of the lattice-gas model and the classical Guggenheim-DiMarzio approximation. In this scheme, the Helmholtz free energy and its derivatives were written in terms of the order parameter, δ, which characterizes the nematic phase occurring in the system at intermediate densities. Then, using the principle of minimum free energy with δ as a parameter, the main adsorption properties were calculated. Comparisons with Monte Carlo simulations and experimental data were performed in order to evaluate the outcome and limitations of the theoretical model.

  16. Algebraic Bethe ansatz for the XXX chain with triangular boundaries and Gaudin model

    Energy Technology Data Exchange (ETDEWEB)

    Cirilo António, N., E-mail: nantonio@math.ist.utl.pt [Centro de Análise Funcional e Aplicações, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Manojlović, N., E-mail: nmanoj@ualg.pt [Grupo de Física Matemática da Universidade de Lisboa, Av. Prof. Gama Pinto 2, PT-1649-003 Lisboa (Portugal); Departamento de Matemática, F.C.T., Universidade do Algarve, Campus de Gambelas, PT-8005-139 Faro (Portugal); Salom, I., E-mail: isalom@ipb.ac.rs [Institute of Physics, University of Belgrade, P.O. Box 57, 11080 Belgrade (Serbia)

    2014-12-15

    We implement fully the algebraic Bethe ansatz for the XXX Heisenberg spin chain in the case when both boundary matrices can be brought to the upper-triangular form. We define the Bethe vectors which yield the strikingly simple expression for the off shell action of the transfer matrix, deriving the spectrum and the relevant Bethe equations. We explore further these results by obtaining the off shell action of the generating function of the Gaudin Hamiltonians on the corresponding Bethe vectors through the so-called quasi-classical limit. Moreover, this action is as simple as it could possibly be, yielding the spectrum and the Bethe equations of the Gaudin model.

  17. Algebraic Bethe ansatz for the XXX chain with triangular boundaries and Gaudin model

    Science.gov (United States)

    Cirilo António, N.; Manojlović, N.; Salom, I.

    2014-12-01

    We implement fully the algebraic Bethe ansatz for the XXX Heisenberg spin chain in the case when both boundary matrices can be brought to the upper-triangular form. We define the Bethe vectors which yield the strikingly simple expression for the off shell action of the transfer matrix, deriving the spectrum and the relevant Bethe equations. We explore further these results by obtaining the off shell action of the generating function of the Gaudin Hamiltonians on the corresponding Bethe vectors through the so-called quasi-classical limit. Moreover, this action is as simple as it could possibly be, yielding the spectrum and the Bethe equations of the Gaudin model.

  18. The magnetic structure on the ground state of the equilateral triangular spin tube

    International Nuclear Information System (INIS)

    Matsui, Kazuki; Goto, Takayuki; Manaka, Hirotaka; Miura, Yoko

    2016-01-01

    The ground state of the frustrated equilateral triangular spin tube CsCrF_4 is still hidden behind a veil though NMR spectrum broaden into 2 T at low temperature. In order to investigate the spin structure in an ordered state by "1"9F-NMR, we have determined the anisotropic hyperfine coupling tensors for each three fluorine sites in the paramagnetic state. The measurement field was raised up to 10 T to achieve highest resolution. The preliminary analysis using the obtained hyperfine tensors has shown that the archetypal 120°-type structure in ab-plane does not accord with the NMR spectra of ordered state.

  19. Impurity States and diamagnetic susceptibility of a donor in a triangular quantum well

    Science.gov (United States)

    Kalpana, P.; Reuben, A. Merwyn Jasper D.; Nithiananthi, P.; Jayakumar, K.

    2017-05-01

    We have calculated the binding energy and the diamagnetic susceptibility(χdia) of the ground (1s) and few low lying excited states (2s and 2p±) in a GaAs/AlxGa1-xAs Triangular Quantum Well (TQW) for the Al composition of x = 0.3. Since the estimation of gives the carrier localization in nanostructured systems and also the calculation of (χdia) involves the , the same has also been estimated as a function of well width. The Schrodinger equation has been solved using variational technique involving Airy functions in the effective mass approximation. The results are presented and discussed.

  20. Study on spin filtering and switching action in a double-triangular network chain

    Science.gov (United States)

    Zhang, Yongmei

    2018-04-01

    Spin transport properties of a double-triangular quantum network with local magnetic moment on backbones and magnetic flux penetrating the network plane are studied. Numerical simulation results show that such a quantum network will be a good candidate for spin filter and spin switch. Local dispersion and density of states are considered in the framework of tight-binding approximation. Transmission coefficients are calculated by the method of transfer matrix. Spin transmission is regulated by substrate magnetic moment and magnetic flux piercing those triangles. Experimental realization of such theoretical research will be conducive to designing of new spintronic devices.

  1. New procedure to design low radar cross section near perfect isotropic and homogeneous triangular carpet cloaks.

    Science.gov (United States)

    Sharifi, Zohreh; Atlasbaf, Zahra

    2016-10-01

    A new design procedure for near perfect triangular carpet cloaks, fabricated based on only isotropic homogeneous materials, is proposed. This procedure enables us to fabricate a cloak with simple metamaterials or even without employing metamaterials. The proposed procedure together with an invasive weed optimization algorithm is used to design carpet cloaks based on quasi-isotropic metamaterial structures, Teflon and AN-73. According to the simulation results, the proposed cloaks have good invisibility properties against radar, especially monostatic radar. The procedure is a new method to derive isotropic and homogeneous parameters from transformation optics formulas so we do not need to use complicated structures to fabricate the carpet cloaks.

  2. Thermodynamic and critical properties of an antiferromagnetically stacked triangular Ising antiferromagnet in a field

    Science.gov (United States)

    Žukovič, M.; Borovský, M.; Bobák, A.

    2018-05-01

    We study a stacked triangular lattice Ising model with both intra- and inter-plane antiferromagnetic interactions in a field, by Monte Carlo simulation. We find only one phase transition from a paramagnetic to a partially disordered phase, which is of second order and 3D XY universality class. At low temperatures we identify two highly degenerate phases: at smaller (larger) fields the system shows long-range ordering in the stacking direction (within planes) but not in the planes (stacking direction). Nevertheless, crossovers to these phases do not have a character of conventional phase transitions but rather linear-chain-like excitations.

  3. Magnetic Properties of New Triangular Lattice Magnets A${_4}$B'B${_2}$O$_{12}$

    OpenAIRE

    Rawl, Ryan; Lee, Minseong; Choi, Eun Sang; Li, Guang; Chen, Kuan-Wen; Baumbach, Ryan; Cruz, Clarina R. dela; Ma, Jie; Zhou, Haidong

    2017-01-01

    The geometrically frustrated two dimensional triangular lattice magnets A${_4}$B'B${_2}$O$_{12}$ (A = Ba, Sr, La; B' = Co, Ni, Mn; B = W, Re) have been studied by x-ray diffraction, AC and DC susceptibilities, powder neutron diffraction, and specific heat measurements. The results reveal that (i) the samples containing Co$^{2+}$ (effective spin-1/2) and Ni$^{2+}$ (spin-1) ions with small spin numbers exhibit ferromagnetic (FM) ordering while the sample containing Mn$^{2+}$ (spin-5/2) ions wit...

  4. Subspace-Based Noise Reduction for Speech Signals via Diagonal and Triangular Matrix Decompositions

    DEFF Research Database (Denmark)

    Hansen, Per Christian; Jensen, Søren Holdt

    We survey the definitions and use of rank-revealing matrix decompositions in single-channel noise reduction algorithms for speech signals. Our algorithms are based on the rank-reduction paradigm and, in particular, signal subspace techniques. The focus is on practical working algorithms, using both...... diagonal (eigenvalue and singular value) decompositions and rank-revealing triangular decompositions (ULV, URV, VSV, ULLV and ULLIV). In addition we show how the subspace-based algorithms can be evaluated and compared by means of simple FIR filter interpretations. The algorithms are illustrated...... with working Matlab code and applications in speech processing....

  5. An algorithm for solving an arbitrary triangular fully fuzzy Sylvester matrix equations

    Science.gov (United States)

    Daud, Wan Suhana Wan; Ahmad, Nazihah; Malkawi, Ghassan

    2017-11-01

    Sylvester matrix equations played a prominent role in various areas including control theory. Considering to any un-certainty problems that can be occurred at any time, the Sylvester matrix equation has to be adapted to the fuzzy environment. Therefore, in this study, an algorithm for solving an arbitrary triangular fully fuzzy Sylvester matrix equation is constructed. The construction of the algorithm is based on the max-min arithmetic multiplication operation. Besides that, an associated arbitrary matrix equation is modified in obtaining the final solution. Finally, some numerical examples are presented to illustrate the proposed algorithm.

  6. Triangular facets of slope in the region of Tudela (Ebro Basin, Navarra, Spain)

    International Nuclear Information System (INIS)

    Marin, C.; Desir, G.; Gutierrez, M.

    2009-01-01

    Some triangular slope facets are localized to the south of Bardenas Reales (central-west of Ebro Basin), elaborated on Tudela Formation deposits, Aragonian in age. Three of them have been dated by OSL resulting on ages of 35,588±2,488 yr. BP, 35,355±2,446 yr. BP and 40.185±2,411 yr. BP. The origin of these facets is ought to an alternation between accumulation and incision phases produced by vegetation cover variation percentage. Those vegetation cover changes are estimated to be due to climatic changes. (Author) 21 refs.

  7. Evaluation of the triangular fibrocartilage complex tears by arthrography and MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Makoto; Shibata, Yasushi [Hokkaido Kin-i-kyou Central Hospital, Sapporo (Japan); Takahata, Naoji

    1995-08-01

    Arthroscopic or open surgical findings in 21 wrists with chronic ulnar painful lesion were compared both with arthrography and magnetic resonance (MR) imaging results to evaluate the accuracy of the two diagnostic procedures in the detection of triangular fibrocartilage complex (TFCC) lesions. Arthrography investigations were performed for the 20 wrists but one that had allergy for iodine and MR imagings were performed for the recent 12 wrists. Arthrography and magnetic resonance (MR) imaging were almost equally useful for the detection of the TFCC injury and their injury sites. (author).

  8. Numerical Study of Thermal Radiation Effect on Confined Turbulent Free Triangular Jets

    Directory of Open Access Journals (Sweden)

    Kiyan Parham

    2013-01-01

    Full Text Available The present study investigates the effects of thermal radiation on turbulent free triangular jets. Finite volume method is applied for solving mass, momentum, and energy equations simultaneously. Discrete ordinate method is used to determine radiation transfer equation (RTE. Results are presented in terms of velocity, kinetic energy, and its dissipation rate fields. Results show that thermal radiation speeds the development of velocity on the jet axis and enhances kinetic energy; therefore, when radiation is added to free jet its mixing power, due to extra kinetic energy, increases.

  9. A New Accurate yet Simple Shear Flexible Triangular Plate Element with Linear Bending Strains

    DEFF Research Database (Denmark)

    Damkilde, Lars; Pedersen, Ronnie

    2010-01-01

    The paper describes a new shear flexible triangular element. The formulation is based on displacement interpolation of the transverse displacement of the midsurface and the rotations of the cross-sections, and the element is fully compatible. The basic principle is to use a so-called balanced...... interpolation so that the part of the shear strains that relates to the transverse displacement has the same polynomial variation as the part of the shear strains that relates to the rotations of the cross-section. This balanced interpolation in combination with complete polynomial interpolations prevents shear...... are virtually the same. The slightly incompatible formulation can be implemented directly into commercial codes....

  10. Measurement and analysis of flow wall shear stress in an interior subchannel of triangular array rods

    International Nuclear Information System (INIS)

    Fakori-Monazah, M.R.; Todreas, N.E.

    1977-08-01

    A simulated model of triangular array rods with pitch to diameter ratio of 1.10 (as a test section) and air as the fluid flow was used to study the LMFBR hydraulic parameters. The wall shear stress distribution around the rod periphery, friction factors, static pressure distributions and turbulence intensity corresponding to various Reynolds numbers ranging from 4140 to 36170 in the central subchannel were measured. Various approaches for measurement of wall shear stress were compared. The measurement was performed using the Preston tube technique with the probe outside diameter equal to 0.014 in

  11. The 120° Ordered Phase of Triangular Lattice Antiferromagnetic Heisenberg Model with Long Range Couplings

    International Nuclear Information System (INIS)

    Zhan-Hai, Dong

    2009-01-01

    In order to look for the 120° order phase of triangular lattice Heisenberg antiferromagnet with long range couplings, the Hamiltonian is diagonalized with the Bogoliubov transformation within linear spin-wave approximation. It is found that when the long range spin couplings are taken into account, the transformation is valid only for certain regions in the spin coupling parameter space. These regions just correspond to the 120° (or Néel) ordered phase, which is very different from square lattice in terms of shape, size and topological property

  12. A numerically accurate and robust expression for bistatic scattering from a plane triangular facet

    DEFF Research Database (Denmark)

    Wendelboe, Gorm; Jacobsen, Finn; Bell, Judith

    2006-01-01

    This work is related to modeling of synthetic sonar images of naval mines or other objects. Considered here is the computation of high frequency scattering from the surface of a rigid 3D-object numerically represented by plane triangular facets. The far field scattered pressure from each facet...... area was applied instead. The effective ensonified area solution is exact at normal incidence, but at other angles, where singularities also exist, the scattered pressure will be incorrect. This paper presents a frequency domain expression generalized to bistatic scattering written in terms of sinc...

  13. Comparable studies of magnetic properties of Ising spins-5/2 and 3/2 systems on decorated square and triangular lattices

    International Nuclear Information System (INIS)

    Masrour, R.; Jabar, A.; Benyoussef, A.; Hamedoun, M.

    2016-01-01

    In this work, we have studied and compared the magnetic properties of Ising spins-5/2 and 3/2 systems on decorated square and triangular lattices using the Monte Carlo simulations. The transition temperature of the two-dimensional decorated square and triangular lattices has been obtained. The effect of the exchange interactions and crystal field on the magnetization is investigated. The magnetic coercive field and saturation magnetization of the two-dimensional decorated square and triangular lattices have been obtained.

  14. Comparable studies of magnetic properties of Ising spins-5/2 and 3/2 systems on decorated square and triangular lattices

    Energy Technology Data Exchange (ETDEWEB)

    Masrour, R., E-mail: rachidmasrour@hotmail.com [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, 63 46000 Safi (Morocco); Jabar, A. [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, 63 46000 Safi (Morocco); Benyoussef, A. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Hassan II Academy of Science and Technology, Rabat (Morocco); Hamedoun, M. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco)

    2016-07-15

    In this work, we have studied and compared the magnetic properties of Ising spins-5/2 and 3/2 systems on decorated square and triangular lattices using the Monte Carlo simulations. The transition temperature of the two-dimensional decorated square and triangular lattices has been obtained. The effect of the exchange interactions and crystal field on the magnetization is investigated. The magnetic coercive field and saturation magnetization of the two-dimensional decorated square and triangular lattices have been obtained.

  15. The effect of shoe design and lateral wedges on knee load and neuromuscular control in healthy subjects during walking

    DEFF Research Database (Denmark)

    Mølgaard, Carsten; Kersting, Uwe G.

    2014-01-01

    The increasing number of patients with developing osteoarthritis is accompanied by a growing scientific interest in non-operative early treatment strategies. It is generally believed that laterally wedged insoles can change the distribution of knee loading. However, the importance of footwear...... wedging is effective regardless of shoe design. Differences between the three neutral walking conditions underline the importance of footwear choice in individuals. It is safe to apply lateral wedges without jeopardising muscular control during walking regardless of shoe type. Possible effects of altering...

  16. The Oldman River triangle zone: a complicated tectonic wedge delineated by new structural mapping and seismic interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Stockmal, G. S. [Geological Survey of Canada, Calgary, AB (Canada). Inst. of Sedimentary and Petroleum Geology; Lawton, D. C.; Spratt, D. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics; MacKay, P. A.

    1996-06-01

    The triangle zone exposed along and adjacent to the Alberta Foothills was characterized on the basis of new structural mapping and seismic surveys. Results indicate that the zone is comprised of a complicated structure involving significant deformation in the hanging wall of the upper detachment, including orogenic thrusts and large orogen-vergent folds, as well as secondary orogen-directed tectonic wedging. This structure is considered to be an example of a `nested` triangle zone, where an `outer` tectonic wedge with modest shortening encases an `inner` counterpart with substantially more shortening. Both of these wedges show evidence of synchronous deformation. 23 refs., 9 figs.

  17. Application of Green's differential equation to the analysis of ion-matrix sheaths around wedge-shaped cathodes

    International Nuclear Information System (INIS)

    Donolato, C

    2005-01-01

    A relation between the gradient of the electric field and mean curvature of equipotential surfaces (Green's differential equation) is applied to a two-dimensional free-boundary problem arising in the study of ion sheaths around wedge-shaped cathodes. With the assumption that the equipotential lines are hyperbolae, this relation leads to a nonlinear ordinary differential equation for the potential along the bisector line of the wedge. An approximate solution is found, which yields, in particular, the sheath width along this line as a function of the wedge angle. The resulting values are in good agreement with published results obtained by numerically solving Poisson's equation

  18. Pulmonary abnormalities in mitral valve disease. Comparison between pulmonary wedge pressure, regional pulmonary blood flow and chest films

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, L H; Andersen, Jr, P E [Odense Univ. (Denmark)

    1978-01-01

    Chest films, right sided heart catheterization, and measurement of the regional lung perfusion, using /sup 133/Xe, were carried out 31 times on patients with mitral valve disease. A relationship was found between the radiologic evaluation in 3 grades, and the values of pulmonary wedge pressure and the apical and basal perfusion. Changes in flow distribution as reflected in altered appearance of the vessels and the presence of interstitial edema were found to be the most sensitive factors in the evaluation of pulmonary wedge pressure. Chest radiography was thus found suitable for the evaluation of pulmonary wedge pressure in mitral valve disease.

  19. Kinematic segmentation of accretive wedges based on scaled sandbox experiments and their application to nature

    Science.gov (United States)

    Lohrmann, J.; Kukowski, N.; Oncken, O.

    2003-04-01

    Recording the incremental displacement field of scaled analogue simulations provides detailed data on wedge kinematics and timing of internal deformation. This is a very efficient tool to develop kinematic concepts and test mechanical theories, e.g. the critical-taper theory. Such models could not be validated until now by the available geological and geophysical data, since there was no information about the incremental displacement field. Recent GPS measurements and seismological investigations at convergent margins provide well-constrained strain-rates and kinematics of short-termed processes. These data allow the kinematic models that are based on analogue simulations to be tested against field observations. We investigate convergent accretive sand wedges in scaled analogue simulations. We define three kinematic segments based on distinctive wedge taper, displacement field and timing of deformation (recorded at a slow sampling rate, which represents the geological scale). Only one of these segments is in a critical state of stress, whereas the other segments are either in a sub-critical or stable state of stress. Such a kinematic segmentation is not predicted for ideally homogeneous wedge-shaped bodies by the critical-taper theory, but can be explained by the formation of localised weak shear zones, which preferentially accommodate deformation. These weak zones are formed in granular analogue materials, and also in natural rocks, since these materials show a strain-softening phase prior to the achievement of stable mechanical conditions. Therefore we suggest that the kinematic segmentation of convergent sand wedges should also be observed in natural settings, such as accretionary wedges, foreland fold-and-thrust belts and even entire orogens. To validate this hypothesis we compare strain rates from GPS measurements and kinematics deduced from focal mechanisms with the respective data from sandbox experiments. We present a strategy to compare strain rates and

  20. Sandbox Simulations of the Evolution of a Subduction Wedge following Subduction Initiation

    Science.gov (United States)

    Brandon, M. T.; Ma, K. F.; DeWolf, W.

    2012-12-01

    Subduction wedges at accreting subduction zones are bounded by a landward dipping pro-shear zone (= subduction thrust) and a seaward-dipping retro-shear zone in the overriding plate. For the Cascadia subduction zone, the surface trace of the retro-shear zone corresponds to the east side of the Coast Ranges of Oregon and Washington and the Insular Mountains of Vancouver Island. This coastal high or forearc high shows clear evidence of long-term uplift and erosion along its entire length, indicating that it is an active part of the Cascadia subduction wedge. The question addressed here is what controls the location of the retro-shear zone? In the popular double-sided wedge model of Willet et al (Geology 1993), the retro-shear zone remains pinned to the S point, which is interpreted to represent where the upper-plate Moho intersects the subduction zone. For this interpretation, the relatively strong mantle is considered to operate as a flat backstop. That model, however. is somewhat artificial in that the two plates collide in a symmetric fashion with equal crustal thicknesses on both sides. Using sandbox experiments, we explore a more realistic configuration where the upper and lower plate are separated by a gentle dipping (10 degree) pro-shear zone, to simulate the initial asymmetric geometry of the subduction thrust immediately after initiation of subduction. The entire lithosphere must fail along some plane for subduction to begin and this failure plane must dip in the direction of subduction. Thus, the initial geometry of the overriding plate is better approximated as a tapered wedge than as a layer of uniform thickness, as represented in the Willett et al models. We demonstrate this model using time-lapse movies of a sand wedge above a mylar subducting plate. We use particle image velocimetry (PIV) to show the evolution of strain and structure within the overriding plate. Material accreted to the tapered end of the overriding plate drives deformation and causes

  1. Estimating effective wedge factor for enhanced dynamic wedge 2100CD a Varian Clinac; Calculo De factor cuna efectiva para cuna dinamica mejorada de un Clinac 2100CD de Varian

    Energy Technology Data Exchange (ETDEWEB)

    Pizarro Trigo, F.; Morillas Ruiz, J.; Nunuz Martinez, L.; Sanchez Jimenez, J.

    2011-07-01

    The purpose of this paper is to compare different methods of calculating the effective factor enhanced dynamic wedge (EDWF) with the values ??obtained in measurements of symmetric and asymmetric fields.

  2. Simulations and measurements of adiabatic annular flows in triangular, tight lattice nuclear fuel bundle model

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, Abhishek, E-mail: asaxena@lke.mavt.ethz.ch [ETH Zurich, Laboratory for Nuclear Energy Systems, Department of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zürich (Switzerland); Zboray, Robert [Laboratory for Thermal-hydraulics, Nuclear Energy and Safety Department, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Prasser, Horst-Michael [ETH Zurich, Laboratory for Nuclear Energy Systems, Department of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zürich (Switzerland); Laboratory for Thermal-hydraulics, Nuclear Energy and Safety Department, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

    2016-04-01

    High conversion light water reactors (HCLWR) having triangular, tight-lattice fuels bundles could enable improved fuel utilization compared to present day LWRs. However, the efficient cooling of a tight lattice bundle has to be still proven. Major concern is the avoidance of high-quality boiling crisis (film dry-out) by the use of efficient functional spacers. For this reason, we have carried out experiments on adiabatic, air-water annular two-phase flows in a tight-lattice, triangular fuel bundle model using generic spacers. A high-spatial-resolution, non-intrusive measurement technology, cold neutron tomography, has been utilized to resolve the distribution of the liquid film thickness on the virtual fuel pin surfaces. Unsteady CFD simulations have also been performed to replicate and compare with the experiments using the commercial code STAR-CCM+. Large eddies have been resolved on the grid level to capture the dominant unsteady flow features expected to drive the liquid film thickness distribution downstream of a spacer while the subgrid scales have been modeled using the Wall Adapting Local Eddy (WALE) subgrid model. A Volume of Fluid (VOF) method, which directly tracks the interface and does away with closure relationship models for interfacial exchange terms, has also been employed. The present paper shows first comparison of the measurement with the simulation results.

  3. Neutron-scattering cross section of the S=1/2 Heisenberg triangular antiferromagnet

    DEFF Research Database (Denmark)

    Lefmann, K.; Hedegård, P.

    1994-01-01

    In this paper we use a Schwinger-boson mean-field approach to calculate the neutron-scattering cross section from the S = 1/2 antiferromagnet with nearest-neighbor isotropic Heisenberg interaction on a two-dimensional triangular lattice. We investigate two solutions for T = 0: (i) a state with lo...... no elastic, but a set of broader dispersive spin excitations around kappa almost-equal-to (1/2, 0) and around kappa almost-equal-to (1/3, 1/3) for omega/E(g) = 2.5-4. It should thus be possible to distinguish these two states in a neutron-scattering experiment.......In this paper we use a Schwinger-boson mean-field approach to calculate the neutron-scattering cross section from the S = 1/2 antiferromagnet with nearest-neighbor isotropic Heisenberg interaction on a two-dimensional triangular lattice. We investigate two solutions for T = 0: (i) a state with long......-range order resembling the Neel state and (ii) a resonating valence bond or ''spin liquid'' state with an energy gap, E(g) almost-equal-to 0.17J, for the elementary excitations (spinons). For solution (ii) the neutron cross section shows Bragg rods at kappa = K = (1/3, 1/3), whereas solution (ii) shows...

  4. Absence of Long-Range Order in a Triangular Spin System with Dipolar Interactions

    Science.gov (United States)

    Keleş, Ahmet; Zhao, Erhai

    2018-05-01

    The antiferromagnetic Heisenberg model on the triangular lattice is perhaps the best known example of frustrated magnets, but it orders at low temperatures. Recent density matrix renormalization group (DMRG) calculations find that the next nearest neighbor interaction J2 enhances the frustration, and it leads to a spin liquid for J2/J1∈(0.08 ,0.15 ). In addition, a DMRG study of a dipolar Heisenberg model with longer range interactions gives evidence for a spin liquid at a small dipole tilting angle θ ∈[0 ,1 0 ° ). In both cases, the putative spin liquid region appears to be small. Here, we show that for the triangular lattice dipolar Heisenberg model, a robust quantum paramagnetic phase exists in a surprisingly wide region, θ ∈[0 ,5 4 ° ) , for dipoles tilted along the lattice diagonal direction. We obtain the phase diagram of the model by functional renormalization group (RG), which treats all magnetic instabilities on equal footing. The quantum paramagnetic phase is characterized by a smooth continuous flow of vertex functions and spin susceptibility down to the lowest RG scale, in contrast to the apparent breakdown of RG flow in phases with stripe or spiral order. Our finding points to a promising direction to search for quantum spin liquids in ultracold dipolar molecules.

  5. Antioxidant, Iron Chelating and Tyrosinase Inhibitory Activities of Extracts from Talinum triangulare Leach Stem

    Directory of Open Access Journals (Sweden)

    Ana Paula Oliveira Amorim

    2013-07-01

    Full Text Available The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE and the hydromethanolic fraction (Fraction 1, resulting in a concentration of 0.5853 g/100 g for Fraction 1, and 0.1400 g/100 g for the CE. Taking into account the results of the DPPH, the free radical scavenging capacity was confirmed. The formation of complexes with Fe II ions was evaluated by UV/visible spectrometry; results showed that CE has complexing power similar to the positive control (Gingko biloba extract.The inhibitory capacity of samples against the tyrosinase enzyme was determined by the oxidation of L-DOPA, providing IC50 values of 13.3 μg·mL−1 (CE and 6.6 μg·mL−1 (Fraction 1. The values indicate that Fraction 1 was more active and showed a higher inhibitory power on the tyrosinase enzyme than the ascorbic acid, used as positive control. The hydromethanolic extract of T. triangulare proved to have powerful antioxidant activity and to inhibit the tyrosinase enzyme; its potential is increased after the partition with chloroform.

  6. High-Order Hyperbolic Residual-Distribution Schemes on Arbitrary Triangular Grids

    Science.gov (United States)

    Mazaheri, Alireza; Nishikawa, Hiroaki

    2015-01-01

    In this paper, we construct high-order hyperbolic residual-distribution schemes for general advection-diffusion problems on arbitrary triangular grids. We demonstrate that the second-order accuracy of the hyperbolic schemes can be greatly improved by requiring the scheme to preserve exact quadratic solutions. We also show that the improved second-order scheme can be easily extended to third-order by further requiring the exactness for cubic solutions. We construct these schemes based on the LDA and the SUPG methodology formulated in the framework of the residual-distribution method. For both second- and third-order-schemes, we construct a fully implicit solver by the exact residual Jacobian of the second-order scheme, and demonstrate rapid convergence of 10-15 iterations to reduce the residuals by 10 orders of magnitude. We demonstrate also that these schemes can be constructed based on a separate treatment of the advective and diffusive terms, which paves the way for the construction of hyperbolic residual-distribution schemes for the compressible Navier-Stokes equations. Numerical results show that these schemes produce exceptionally accurate and smooth solution gradients on highly skewed and anisotropic triangular grids, including curved boundary problems, using linear elements. We also present Fourier analysis performed on the constructed linear system and show that an under-relaxation parameter is needed for stabilization of Gauss-Seidel relaxation.

  7. Triangular node for Transmission-Line Modeling (TLM) applied to bio-heat transfer.

    Science.gov (United States)

    Milan, Hugo F M; Gebremedhin, Kifle G

    2016-12-01

    Transmission-Line Modeling (TLM) is a numerical method used to solve complex and time-domain bio-heat transfer problems. In TLM, rectangles are used to discretize two-dimensional problems. The drawback in using rectangular shapes is that instead of refining only the domain of interest, a large additional domain will also be refined in the x and y axes, which results in increased computational time and memory space. In this paper, we developed a triangular node for TLM applied to bio-heat transfer that does not have the drawback associated with the rectangular nodes. The model includes heat source, blood perfusion (advection), boundary conditions and initial conditions. The boundary conditions could be adiabatic, temperature, heat flux, or convection. A matrix equation for TLM, which simplifies the solution of time-domain problems or solves steady-state problems, was also developed. The predicted results were compared against results obtained from the solution of a simplified two-dimensional problem, and they agreed within 1% for a mesh length of triangular faces of 59µm±9µm (mean±standard deviation) and a time step of 1ms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Electron-related linear and nonlinear optical responses in vertically coupled triangular quantum dots

    International Nuclear Information System (INIS)

    Martínez-Orozco, J.C.; Mora-Ramos, M.E.; Duque, C.A.

    2014-01-01

    The conduction band states of GaAs-based vertically coupled double triangular quantum dots in two dimensions are investigated within the effective mass and parabolic approximation, using a diagonalization procedure to solve the corresponding Schrödinger-like equation. The effect of an externally applied static electric field is included in the calculation, and the variation of the lowest confined energy levels as a result of the change of the field strength is reported for different geometrical setups. The linear and nonlinear optical absorptions and the relative change of the refractive index, associated with the energy transition between the ground and the first excited state in the system, are studied as a function of the incident light frequency for distinct configurations of inter-dot distance and electric field intensities. The blueshift of the resonant absorption peaks is detected as a consequence of the increment in the field intensity, whereas the opposite effect is obtained from the increase of inter-dot vertical distance. It is also shown that for large enough values of the electric field there is a quenching of the optical absorption due to field-induced change of symmetry of the first excited state wavefunction, in the case of triangular dots of equal shape and size

  9. Electron-related linear and nonlinear optical responses in vertically coupled triangular quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Orozco, J.C. [Unidad Académica de Física. Universidad Autónoma de Zacatecas, Calzada Solidaridad esquina con Paseo la Bufa S/N, C.P. 98060. Zacatecas, Zac. (Mexico); Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Mora-Ramos, M.E. [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Ave. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico); Duque, C.A., E-mail: cduque@fisica.udea.edu.co [Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia)

    2014-11-01

    The conduction band states of GaAs-based vertically coupled double triangular quantum dots in two dimensions are investigated within the effective mass and parabolic approximation, using a diagonalization procedure to solve the corresponding Schrödinger-like equation. The effect of an externally applied static electric field is included in the calculation, and the variation of the lowest confined energy levels as a result of the change of the field strength is reported for different geometrical setups. The linear and nonlinear optical absorptions and the relative change of the refractive index, associated with the energy transition between the ground and the first excited state in the system, are studied as a function of the incident light frequency for distinct configurations of inter-dot distance and electric field intensities. The blueshift of the resonant absorption peaks is detected as a consequence of the increment in the field intensity, whereas the opposite effect is obtained from the increase of inter-dot vertical distance. It is also shown that for large enough values of the electric field there is a quenching of the optical absorption due to field-induced change of symmetry of the first excited state wavefunction, in the case of triangular dots of equal shape and size.

  10. One dimensionalization in the spin-1 Heisenberg model on the anisotropic triangular lattice

    Science.gov (United States)

    Gonzalez, M. G.; Ghioldi, E. A.; Gazza, C. J.; Manuel, L. O.; Trumper, A. E.

    2017-11-01

    We investigate the effect of dimensional crossover in the ground state of the antiferromagnetic spin-1 Heisenberg model on the anisotropic triangular lattice that interpolates between the regime of weakly coupled Haldane chains (J'≪J ) and the isotropic triangular lattice (J'=J ). We use the density-matrix renormalization group (DMRG) and Schwinger boson theory performed at the Gaussian correction level above the saddle-point solution. Our DMRG results show an abrupt transition between decoupled spin chains and the spirally ordered regime at (J'/J) c˜0.42 , signaled by the sudden closing of the spin gap. Coming from the magnetically ordered side, the computation of the spin stiffness within Schwinger boson theory predicts the instability of the spiral magnetic order toward a magnetically disordered phase with one-dimensional features at (J'/J) c˜0.43 . The agreement of these complementary methods, along with the strong difference found between the intra- and the interchain DMRG short spin-spin correlations for sufficiently large values of the interchain coupling, suggests that the interplay between the quantum fluctuations and the dimensional crossover effects gives rise to the one-dimensionalization phenomenon in this frustrated spin-1 Hamiltonian.

  11. Handwriting features of children with developmental coordination disorder--results of triangular evaluation.

    Science.gov (United States)

    Rosenblum, Sara; Margieh, Jumana Aassy; Engel-Yeger, Batya

    2013-11-01

    Developmental coordination disorders (DCD) is one of the most common disorders affecting school-aged children. The study aimed to characterize the handwriting performance of children with DCD who write in Arabic, based on triangular evaluation. Participants included 58 children aged 11-12 years, 29 diagnosed with DCD based on the DSM-IV criteria and the M-ABC, and 29 matched typically developed controls. Children were asked to copy a paragraph on a sheet of paper affixed to a digitizer supplying objective measures of the handwriting process. The handwriting proficiency screening questionnaire (HPSQ) was completed by their teachers while observing their performance and followed by evaluation of their final written product. Results indicated that compared to controls, children with DCD required significantly more on-paper and in-air time per stroke while copying. In addition, global legibility, unrecognizable letters and spatial arrangement measures of their written product were significantly inferior. Significant group differences were also found between the HPSQ subscales scores. Furthermore, 82.8% of all participants were correctly classified into groups based on one discriminate function which included two handwriting performance measures. These study results strongly propose application of triangular standardized evaluation to receive better insight of handwriting deficit features of individual children with DCD who write in Arabic. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. High-Resolution 3T MR Imaging of the Triangular Fibrocartilage Complex.

    Science.gov (United States)

    von Borstel, Donald; Wang, Michael; Small, Kirstin; Nozaki, Taiki; Yoshioka, Hiroshi

    2017-01-10

    This study is intended as a review of 3Tesla (T) magnetic resonance (MR) imaging of the triangular fibrocartilage complex (TFCC). The recent advances in MR imaging, which includes high field strength magnets, multi-channel coils, and isotropic 3-dimensional (3D) sequences have enabled the visualization of precise TFCC anatomy with high spatial and contrast resolution. In addition to the routine wrist protocol, there are specific techniques used to optimize 3T imaging of the wrist; including driven equilibrium sequence (DRIVE), parallel imaging, and 3D imaging. The coil choice for 3T imaging of the wrist depends on a number of variables, and the proper coil design selection is critical for high-resolution wrist imaging with high signal and contrast-to-noise ratio. The TFCC is a complex structure and is composed of the articular disc (disc proper), the triangular ligament, the dorsal and volar radioulnar ligaments, the meniscus homologue, the ulnar collateral ligament (UCL), the extensor carpi ulnaris (ECU) tendon sheath, and the ulnolunate and ulnotriquetral ligaments. The Palmer classification categorizes TFCC lesions as traumatic (type 1) or degenerative (type 2). In this review article, we present clinical high-resolution MR images of normal TFCC anatomy and TFCC injuries with this classification system.

  13. A fast iterative model for discrete velocity calculations on triangular grids

    International Nuclear Information System (INIS)

    Szalmas, Lajos; Valougeorgis, Dimitris

    2010-01-01

    A fast synthetic type iterative model is proposed to speed up the slow convergence of discrete velocity algorithms for solving linear kinetic equations on triangular lattices. The efficiency of the scheme is verified both theoretically by a discrete Fourier stability analysis and computationally by solving a rarefied gas flow problem. The stability analysis of the discrete kinetic equations yields the spectral radius of the typical and the proposed iterative algorithms and reveal the drastically improved performance of the latter one for any grid resolution. This is the first time that stability analysis of the full discrete kinetic equations related to rarefied gas theory is formulated, providing the detailed dependency of the iteration scheme on the discretization parameters in the phase space. The corresponding characteristics of the model deduced by solving numerically the rarefied gas flow through a duct with triangular cross section are in complete agreement with the theoretical findings. The proposed approach may open a way for fast computation of rarefied gas flows on complex geometries in the whole range of gas rarefaction including the hydrodynamic regime.

  14. GPU-Accelerated Population Annealing Algorithm: Frustrated Ising Antiferromagnet on the Stacked Triangular Lattice

    Directory of Open Access Journals (Sweden)

    Borovský Michal

    2016-01-01

    Full Text Available The population annealing algorithm is a novel approach to study systems with rough free-energy landscapes, such as spin glasses. It combines the power of simulated annealing, Boltzmann weighted differential reproduction and sequential Monte Carlo process to bring the population of replicas to the equilibrium even in the low-temperature region. Moreover, it provides a very good estimate of the free energy. The fact that population annealing algorithm is performed over a large number of replicas with many spin updates, makes it a good candidate for massive parallelism. We chose the GPU programming using a CUDA implementation to create a highly optimized simulation. It has been previously shown for the frustrated Ising antiferromagnet on the stacked triangular lattice with a ferromagnetic interlayer coupling, that standard Markov Chain Monte Carlo simulations fail to equilibrate at low temperatures due to the effect of kinetic freezing of the ferromagnetically ordered chains. We applied the population annealing to study the case with the isotropic intra- and interlayer antiferromagnetic coupling (J2/|J1| = −1. The reached ground states correspond to non-magnetic degenerate states, where chains are antiferromagnetically ordered, but there is no long-range ordering between them, which is analogical with Wannier phase of the 2D triangular Ising antiferromagnet.

  15. Numerical investigation of Al2O3/water nanofluid laminar convective heat transfer through triangular ducts

    Directory of Open Access Journals (Sweden)

    Zeinali Heris Saeed

    2011-01-01

    Full Text Available Abstract In this article, laminar flow-forced convective heat transfer of Al2O3/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid and pure fluid heat transfer is achieved in this article. Sometimes, because of pressure drop limitations, the need for non-circular ducts arises in many heat transfer applications. The low heat transfer rate of non-circular ducts is one the limitations of these systems, and utilization of nanofluid instead of pure fluid because of its potential to increase heat transfer of system can compensate this problem. In this article, for considering the presence of nanoparticl: es, the dispersion model is used. Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct. The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter. Also, the enhancement of the fluid heat transfer becomes better at high Re in laminar flow with the addition of nanoparticles.

  16. Using Chebyshev polynomials and approximate inverse triangular factorizations for preconditioning the conjugate gradient method

    Science.gov (United States)

    Kaporin, I. E.

    2012-02-01

    In order to precondition a sparse symmetric positive definite matrix, its approximate inverse is examined, which is represented as the product of two sparse mutually adjoint triangular matrices. In this way, the solution of the corresponding system of linear algebraic equations (SLAE) by applying the preconditioned conjugate gradient method (CGM) is reduced to performing only elementary vector operations and calculating sparse matrix-vector products. A method for constructing the above preconditioner is described and analyzed. The triangular factor has a fixed sparsity pattern and is optimal in the sense that the preconditioned matrix has a minimum K-condition number. The use of polynomial preconditioning based on Chebyshev polynomials makes it possible to considerably reduce the amount of scalar product operations (at the cost of an insignificant increase in the total number of arithmetic operations). The possibility of an efficient massively parallel implementation of the resulting method for solving SLAEs is discussed. For a sequential version of this method, the results obtained by solving 56 test problems from the Florida sparse matrix collection (which are large-scale and ill-conditioned) are presented. These results show that the method is highly reliable and has low computational costs.

  17. Mean streamwise velocity measurements in a triple jet of equilateral triangular configuration

    Energy Technology Data Exchange (ETDEWEB)

    Moustafa, G.H. (Menoufia Univ. (Egypt). Coll. of Engineering); Sundararajan, T. (IIT Kanpur (India). Dept. of Mechanical Engineering); Rathakrishnan, E. (IIT Kanpur (India). Dept. of Aerospace Engineering)

    1993-09-01

    Multijet flows arise in several applications such as jet engine/rocket combustors, the thrust augmenting ejectors for VTOL/STOL aircraft, and industrial gas burners. In order to achieve proper combustion, thrust development, and reduction in the noise level, it is often desirable to control the inter-mixing between the jets and also the entrainment of the surrounding atmosphere. This, in turn, requires a detailed study of the behavior of high speed jets in multijet configuration. The situation of interest here is an array of three axisymmetric nozzles set in a common end wall with equal spacing in a triangular configuration. The reason why this particular configuration has been chosen is that it promotes bending of the jet axes toward each other, thus leading to greater mixing. In the present study, experiments have been conducted to investigate the effect of stagnation pressure ratio and nozzle spacing upon the mean flow characteristic of compressible jets in triangular configuration. The individual flow features of the vertex jet and the base twin jet are analyzed and their contributions to the axis switching as well as the overall triple jet behavior are highlighted.

  18. Structural control of the Gagua "Wedge" Zone east of Taiwan Island on the southern Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    ZHENG; Yanpeng; LIU; Baohua; WU; Jinlong; LIANG; Ruicai; L

    2005-01-01

    Based on compositive analysis and interpretation of the observed and historical data, the geophysical field characters and structural properties of the Gagua "Wedge" Zone of the sea area east of Taiwan Island and the primary tectonic stress direction and its variabilities of backarc spreading in the southern Okinawa Trough are studied. It is concluded from the study results that the Gagua "Wedge" Zone is structurally consistent with the Gagua ridge and two fault basins on both sides of the Gagua ridge, and adjusts the moving direction and distance of the western Philippine Sea plate to make the northwestward motion of the plate on its east side change to the northward subduction of the plate on its west side so that the primary tectonic stress direction of the Okinawa Trough changed from NW-SE to nearly N-S, which provided the stress source for the Okinawa Trough to enter the second spreading stage.

  19. Dosimetry of normal and wedge fields for a cobalt-60 teletherapy unit

    International Nuclear Information System (INIS)

    Tripathi, U.B.; Kelkar, N.Y.

    1980-01-01

    A simple analytical method for computation of dose distributions for normal and wedge fields is described and the use of the method in planning radiation treatment is outlined. Formulas has been given to compute: (1) depth dose along central axis of cobalt-60 beam, (2) dose to off-axis points, and (3) dose distribution for a wedge field. Good agreement has been found between theoretical and experimental values. With the help of these formulae, the dose at any point can be easily and accurately calculated and radiotherapy can be planned for tumours of very odd shape and sizes. The limitation of the method is that the formulae have been derived for 50% field definition. For cobalt-60 machine having any other field definition, appropriate correction factors have to be applied. (M.G.B.)

  20. Fabrication of customizable wedged multilayer Laue lenses by adding a stress layer

    International Nuclear Information System (INIS)

    Niese, Sven; Krüger, Peter; Kubec, Adam; Laas, Roman; Gawlitza, Peter; Melzer, Kathleen; Braun, Stefan; Zschech, Ehrenfried

    2014-01-01

    Diffractive optics for hard X-rays feature superior properties in terms of resolution and efficiency, if volume diffraction effects are exploited all-over the aperture. For multilayer Laue lenses, preferably a wedged geometry is required to obtain this effect. We present an approach utilizing an additional stress layer to realize the necessary geometrical modifications where each lens can be customized to a selected photon energy independently of the given multilayer deposition. The quality of the deposition of the stress layer is evaluated using a laboratory X-ray microscope prior to its application at synchrotron radiation facilities with a special approach to measure the relative layer tilt at high spatial resolution. - Highlights: • Wedged multilayer Laue lenses were fabricated using an additional stress layer. • Each lens can be customized to any photon energy independently of the multilayer. • The relative layer tilt is measured using laboratory X-ray microscopy

  1. Physical Analysis of Cross-Wedge Rolling Process of a Stepped Shaft

    Directory of Open Access Journals (Sweden)

    Łukasz Wójcik

    2017-12-01

    Full Text Available The paper presents experimental- model research results on the process of cross-wedge rolling of an axially-symmetrical element (stepped shaft. During research was used plastic mass on the basis of waxes in black and white colour. The aim of this experimental research was to determine the best option of forming in terms of values obtained and the course of forces. Physical examination was carried out using specialist machines, that is model and laboratory cross-wedge rolling mill. Experimental analysis was carried out using billets with the temperature of 15°C, whereas the actual process was carried out for billet from C45 carbon steel of temperature 1150°C. The study compared the dimensions of the components obtained during rolling tests and forming forces obtained in the result of physical modeling with forces obtained during real tests.

  2. Laser Oscillator Incorporating a Wedged Polarization Rotator and a Porro Prism as Cavity Mirror

    Science.gov (United States)

    Li, Steven

    2011-01-01

    A laser cavity was designed and implemented by using a wedged polarization rotator and a Porro prism in order to reduce the parts count, and to improve the laser reliability. In this invention, a z-cut quartz polarization rotator is used to compensate the wavelength retardance introduced by the Porro prism. The polarization rotator rotates the polarization of the linear polarized beam with a designed angle that is independent of the orientation of the rotator. This unique property was used to combine the retardance compensation and a Risley prism to a single optical component: a wedged polarization rotator. This greatly simplifies the laser alignment procedure and reduces the number of the laser optical components.

  3. Generation of vector beams using a double-wedge depolarizer: Non-quantum entanglement

    Science.gov (United States)

    Samlan, C. T.; Viswanathan, Nirmal K.

    2016-07-01

    Propagation of horizontally polarized Gaussian beam through a double-wedge depolarizer generates vector beams with spatially varying state of polarization. Jones calculus is used to show that such beams are maximally nonseparable on the basis of even (Gaussian)-odd (Hermite-Gaussian) mode parity and horizontal-vertical polarization state. The maximum nonseparability in the two degrees of freedom of the vector beam at the double wedge depolarizer output is verified experimentally using a modified Sagnac interferometer and linear analyser projected interferograms to measure the concurrence 0.94±0.002 and violation of Clauser-Horne-Shimony-Holt form of Bell-like inequality 2.704±0.024. The investigation is carried out in the context of the use of vector beams for metrological applications.

  4. [A Patient with a Wedge-shaped Pulmonary Lesion Associated with Streptococcus parasanguinis].

    Science.gov (United States)

    Miyamoto, Hiroya; Gomi, Harumi; Ishioka, Haruhiko; Shirokawa, Taijiro

    2016-05-01

    An 84-year-old man was admitted to our hospital with bloody sputum. He was found to have a right lower lobe wedge-shaped nodular lesion with chest X-ray and computed tomography of the chest. Ceftriaxone and minocycline were started empirically based on a working diagnosis of community-acquired pneumonia. Streptococcus parasanguinis was isolated with sputum cultures obtained on three consecutive days and was identified based on its biochemical properties. S. parasanguinis is a member of the sanguinis group of viridans Streptococci. It is known as a causative pathogen for endocarditis. There are very few reports of S. parasanguinis associated with pulmonary infections. The present report describes the association of S. parasanguinis with a wedge-shaped nodular lesion in the lungs.

  5. Soil carbon sequestration is a climate stabilization wedge: comments on Sommer and Bossio (2014).

    Science.gov (United States)

    Lassaletta, Luis; Aguilera, Eduardo

    2015-04-15

    Sommer and Bossio (2014) model the potential soil organic carbon (SOC) sequestration in agricultural soils (croplands and grasslands) during the next 87 years, concluding that this process cannot be considered as a climate stabilization wedge. We argue, however, that the amounts of SOC potentially sequestered in both scenarios (pessimistic and optimistic) fulfil the requirements for being considered as wedge because in both cases at least 25 GtC would be sequestered during the next 50 years. We consider that it is precisely in the near future, and meanwhile other solutions are developed, when this stabilization effort is most urgent even if after some decades the sequestration rate is significantly reduced. Indirect effects of SOC sequestration on mitigation could reinforce the potential of this solution. We conclude that the sequestration of organic carbon in agricultural soils as a climate change mitigation tool still deserves important attention for scientists, managers and policy makers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Study into critical properties of 3D frustrated Heisenberg model on triangular lattice by the use of Monte Carlo methods

    International Nuclear Information System (INIS)

    Murtazaev, A.K.; Ramazanov, M.K.; Badiev, M.K.

    2009-01-01

    The critical properties of the 3D frustrated antiferromagnetic Heisenberg model on a triangular lattice are investigated by the replica Monte Carlo method. The static magnetic and chiral critical exponents of heat capacity a = 0.05(2), magnetization Β 0.30(1), Β k = 0.52(2), susceptibility Γ = 1.36(2), Γ k = 0.93(3), and correlation radius Ν 0.64(1), Ν k = 0.64(2) are calculated by using the finitesize scaling theory. The critical Fisher exponents η = - 0.06(3), η k = 0.63(4) for this model are estimated for the first time. A new universality class of the critical behavior is shown to be formed by the 3D frustrated Heisenberg model on the triangular lattice. A type of the interlayer exchange interaction is found to influence the universality class of antiferromagnetic Heisenberg model on the a triangular lattice.

  7. Laser cutting of triangular geometry into 2024 aluminum alloy: Influence of triangle size on thermal stress field

    Energy Technology Data Exchange (ETDEWEB)

    Yilbas, Bekir Sami; Akhtar, Syed Sohail [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Keles, Omer; Boran, Kurtulus [Gazi University, Ankara (Turkmenistan)

    2015-08-15

    Laser cutting of a triangular geometry into aluminum 2024 alloy is carried out. Thermal stress field in the cutting section is predicted using the finite element code ABAQUS. Surface temperature predictions are validated through the thermocouple data. Morphological changes in the cut section are examined incorporating optical and electron scanning microscopes. The effects of the size of the triangular geometry on thermal stress field are also examined. It is found that surface temperature predictions agree well with thermocouple data. von Mises stress remains high in the region close to the corners of the triangular geometry, which is more pronounced for the small size triangle. This behavior is associated with the occurrence of the high cooling rates in this region. Laser cut edges are free from large scale sideways burning and large size burr attachments. However, some locally scattered dross attachments are observed at the kerf exit.

  8. Muon Intensity Increase by Wedge Absorbers for Low-E Muon Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, D. V. [Fermilab; Stratakis, D. [Fermilab; Bradley, J. [Fermilab

    2017-09-01

    Low energy muon experiments such as mu2e and g-2 have a limited energy spread acceptance. Following techniques developed in muon cooling studies and the MICE experiment, the number of muons within the desired energy spread can be increased by the matched use of wedge absorbers. More generally, the phase space of muon beams can be manipulated by absorbers in beam transport lines. Applications with simulation results are presented.

  9. RANS Analyses of Turbofan Nozzles with Internal Wedge Deflectors for Noise Reduction

    Science.gov (United States)

    DeBonis, James R.

    2009-01-01

    Computational fluid dynamics (CFD) was used to evaluate the flow field and thrust performance of a promising concept for reducing the noise at take-off of dual-stream turbofan nozzles. The concept, offset stream technology, reduces the jet noise observed on the ground by diverting (offsetting) a portion of the fan flow below the core flow, thickening and lengthening this layer between the high-velocity core flow and the ground observers. In this study a wedge placed in the internal fan stream is used as the diverter. Wind, a Reynolds averaged Navier-Stokes (RANS) code, was used to analyze the flow field of the exhaust plume and to calculate nozzle performance. Results showed that the wedge diverts all of the fan flow to the lower side of the nozzle, and the turbulent kinetic energy on the observer side of the nozzle is reduced. This reduction in turbulent kinetic energy should correspond to a reduction in noise. However, because all of the fan flow is diverted, the upper portion of the core flow is exposed to the freestream, and the turbulent kinetic energy on the upper side of the nozzle is increased, creating an unintended noise source. The blockage due to the wedge reduces the fan mass flow proportional to its blockage, and the overall thrust is consequently reduced. The CFD predictions are in very good agreement with experimental flow field data, demonstrating that RANS CFD can accurately predict the velocity and turbulent kinetic energy fields. While this initial design of a large scale wedge nozzle did not meet noise reduction or thrust goals, this study identified areas for improvement and demonstrated that RANS CFD can be used to improve the concept.

  10. Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges.

    Science.gov (United States)

    Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

    2016-05-01

    Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10(-3) S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10(-1) S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front.

  11. Fluxes and burial of particulate organic carbon along the Adriatic mud-wedge (Mediterranean Sea)

    Science.gov (United States)

    Tesi, T.; Langone, L.; Giani, M.; Ravaioli, M.; Miserocchi, S.

    2012-04-01

    Clinoform-shaped deposits are ubiquitous sedimentological bodies of modern continental margins, including both carbonate and silicoclastic platforms. They formed after the attainment of the modern sea level high-stand (mid-late Holocene) when river outlets and shoreline migrated landward. As clinoform-shape deposits are essential building blocks of the infill of sedimentary basins, they are sites of intense organic carbon (OC) deposition and account for a significant fraction of OC burial in the ocean during interglacial periods. In this study, we focused on sigmoid clinoforms that are generally associated with low-energy environments. In particular, we characterized the modern accumulation and burial of OC along the late-Holocene sigmoid in the Western Adriatic Sea (Mediterranean Sea). This sedimentary body consists of a mud wedge recognizable on seismic profiles as a progradational unit lying on top the maximum flooding surface that marks the time of maximum landward shift of the shoreline attained around 5.5 kyr cal BP. In the last two decades, several projects have investigated sediment dynamics and organic geochemistry along the Adriatic mud wedge (e.g., PRISMA, EURODELTA, EuroSTRATAFORM, PASTA, CIPE, VECTOR). All these studies increased our understanding of strata formation and organic matter cycling in this epicontinental margin. The overarching goal of this study was to combine the results gained during these projects with newly acquired data to assess fluxes to seabed and burial efficiency of organic carbon along the uppermost strata of the Adriatic mud-wedge. Our study benefited of an extensive number of radionuclide-based (Pb-210, and Cs-137) sediment accumulation rates and numerous biogeochemical data of surface sediments and sediment cores (organic carbon, total nitrogen, radiocarbon measurements, carbon stable isotopes, and biomarkers). In addition, because the accumulation of river-borne sediment may or may not be linked to a specific source, another

  12. Variation of beam characteristics for physical and enhanced dynamic wedge from a dual energy accelerator

    International Nuclear Information System (INIS)

    Varatharaj, C.; Ravikumar, M.; Sathiyan, S.; Supe, Sanjay S.

    2008-01-01

    The use of Megavoltage X-ray sources of radiation, with their skin-sparing qualities in radiation therapy has been a boon in relieving patient discomfort and allowing higher tumor doses to be given with fewer restrictions due to radiation effects in the skin. The aim of this study was to compare few of the dosimetric characteristics of a physical and enhanced dynamic wedge from a dual energy (6-18 MV) linear accelerator

  13. Open wedge high tibial osteotomy using three-dimensional printed models: Experimental analysis using porcine bone.

    Science.gov (United States)

    Kwun, Jun-Dae; Kim, Hee-June; Park, Jaeyoung; Park, Il-Hyung; Kyung, Hee-Soo

    2017-01-01

    The purpose of this study was to evaluate the usefulness of three-dimensional (3D) printed models for open wedge high tibial osteotomy (HTO) in porcine bone. Computed tomography (CT) images were obtained from 10 porcine knees and 3D imaging was planned using the 3D-Slicer program. The osteotomy line was drawn from the three centimeters below the medial tibial plateau to the proximal end of the fibular head. Then the osteotomy gap was opened until the mechanical axis line was 62.5% from the medial border along the width of the tibial plateau, maintaining the posterior tibial slope angle. The wedge-shaped 3D-printed model was designed with the measured angle and osteotomy section and was produced by the 3D printer. The open wedge HTO surgery was reproduced in porcine bone using the 3D-printed model and the osteotomy site was fixed with a plate. Accuracy of osteotomy and posterior tibial slope was evaluated after the osteotomy. The mean mechanical axis line on the tibial plateau was 61.8±1.5% from the medial tibia. There was no statistically significant difference (P=0.160). The planned and post-osteotomy correction wedge angles were 11.5±3.2° and 11.4±3.3°, and the posterior tibial slope angle was 11.2±2.2° pre-osteotomy and 11.4±2.5° post-osteotomy. There were no significant differences (P=0.854 and P=0.429, respectively). This study showed that good results could be obtained in high tibial osteotomy by using 3D printed models of porcine legs. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Changes in patellofemoral alignment do not cause clinical impact after open-wedge high tibial osteotomy.

    Science.gov (United States)

    Lee, Yong Seuk; Lee, Sang Bok; Oh, Won Seok; Kwon, Yong Eok; Lee, Beom Koo

    2016-01-01

    The objectives of this study were (1) to evaluate the clinical and radiologic outcomes of open-wedge high tibial osteotomy focusing on patellofemoral alignment and (2) to search for correlation between variables and patellofemoral malalignment. A total of 46 knees (46 patients) from 32 females and 14 males who underwent open-wedge high tibial osteotomy were included in this retrospective case series. Outcomes were evaluated using clinical scales and radiologic parameters at the last follow-up. Pre-operative and final follow-up values were compared for the outcome analysis. For the focused analysis of the patellofemoral joint, correlation analyses between patellofemoral variables and pre- and post-operative weight-bearing line (WBL), clinical score, posterior slope, Blackburn Peel ratio, lateral patellar tilt, lateral patellar shift, and congruence angle were performed. The minimum follow-up period was 2 years and median follow-up period was 44 months (range 24-88 months). The percentage of weight-bearing line was shifted from 17.2 ± 11.1 to 56.7 ± 12.7%, and it was statistically significant (p patellofemoral malalignment, the pre-operative weight-bearing line showed an association with the change in lateral patellar tilt and lateral patellar shift (correlation coefficient: 0.3). After open-wedge high tibial osteotomy, clinical results showed improvement, compared to pre-operative values. The patellar tilt and lateral patellar shift were not changed; however, descent of the patella was observed. Therefore, mild patellofemoral problems should not be a contraindication of the open-wedge high tibial osteotomy. Case series, Level IV.

  15. Wedge-Splitting Test – Determination of Minimal Starting Notch Length for Various Cement Based Composites

    Czech Academy of Sciences Publication Activity Database

    Seitl, Stanislav; Klusák, Jan; Veselý, V.; Řoutil, L.

    452-453, - (2011), s. 81-84 ISSN 1013-9826 R&D Projects: GA AV ČR KJB200410901; GA ČR GA103/08/0963 Institutional research plan: CEZ:AV0Z20410507 Keywords : wedge-splitting test, cementitious composites, quasi-brittle fracture, brittle fracture Subject RIV: JL - Materials Fatigue, Friction Mechanics www.scientific.net

  16. 2D Traveling Wave Array Employing a Trapezoidal Dielectric Wedge for Beam Steering

    Science.gov (United States)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranada, Felix A.

    2014-01-01

    This presentation addresses the progress made so far in the development of an antenna array with reconfigurable transmission line feeds connecting each element in series. In particular, 2D traveling wave array employing trapezoidal Dielectric Wedge for Beam Steering will be discussed. The presentation includes current status of the effort and suggested future work. The work is being done as part of the NASA Office of the Chief Technologist's Space Technology Research Fellowship (NSTRF).

  17. Infarction and Laceration of Liver Parenchyma Caused by Wedged CO2 Venography Before TIPS Insertion

    International Nuclear Information System (INIS)

    Theuerkauf, Ingo; Strunk, Holger; Brensing, Karl August; Schild, Hans Heinz; Pfeifer, Ulrich

    2001-01-01

    We describe the fatal outcome of an elective TIPS procedure performed in a 43-year-old man with alcoholic cirrhosis. Wedged hepatic venography with CO 2 was the reason for infarction and laceration of liver parenchyma resulting in a subcapsular hematoma and subsequent intra-abdominal bleeding. This is the first report of this complication after the use of CO 2 in a cirrhotic patient

  18. Thermal regime of an ice-wedge polygon landscape near Barrow, Alaska

    Science.gov (United States)

    Daanen, R. P.; Liljedahl, A. K.

    2017-12-01

    Tundra landscapes are changing all over the circumpolar Arctic due to permafrost degradation. Soil cracking and infilling of meltwater repeated over thousands of years form ice wedges, which produce the characteristic surface pattern of ice-wedge polygon tundra. Rapid top-down thawing of massive ice leads to differential ground subsidence and sets in motion a series of short- and long-term hydrological and ecological changes. Subsequent responses in the soil thermal regime drive further permafrost degradation and/or stabilization. Here we explore the soil thermal regime of an ice-wedge polygon terrain near Utqiagvik (formerly Barrow) with the Water balance Simulation Model (WaSiM). WaSiM is a hydro-thermal model developed to simulate the water balance at the watershed scale and was recently refined to represent the hydrological processes unique to cold climates. WaSiM includes modules that represent surface runoff, evapotranspiration, groundwater, and soil moisture, while active layer freezing and thawing is based on a direct coupling of hydrological and thermal processes. A new snow module expands the vadose zone calculations into the snow pack, allowing the model to simulate the snow as a porous medium similar to soil. Together with a snow redistribution algorithm based on local topography, this latest addition to WaSiM makes simulation of the ground thermal regime much more accurate during winter months. Effective representation of ground temperatures during winter is crucial in the simulation of the permafrost thermal regime and allows for refined predictions of future ice-wedge degradation or stabilization.

  19. Stratification and salt-wedge in the Seomjin river estuary under the idealized tidal influence

    Science.gov (United States)

    Hwang, Jin Hwan; Jang, Dongmin; Kim, Yong Hoon

    2017-12-01

    Advection, straining, and vertical mixing play primary roles in the process of estuarine stratification. Estuaries can be classified as salt-wedge, partially-mixed or well-mixed depending on the vertical density structure determined by the balancing of advection, mixing and straining. In particular, straining plays a major role in the stratification of the estuarine water body along the estuarine channel. Also, the behavior of a salt wedge with a halocline shape in a stratified channel can be controlled by the competition between straining and mixing induced by buoyancy from the riverine source and tidal forcing. The present study uses Finite Volume Coastal Ocean Model (FVCOM) to show that straining and vertical mixing play major roles in controlling along-channel flow and stratification structures in the Seomjin river estuary (SRE) under idealized conditions. The Potential Energy Anomaly (PEA) dynamic equation quantifies the governing processes thereby enabling the determination of the stratification type. By comparing terms in the equation, we examined how the relative strengths of straining and mixing alter the stratification types in the SRE due to changes in river discharge and the depth resulting from dredging activities. SRE under idealized tidal forcing tends to be partially-mixed based on an analysis of the balance between terms and the vertical structure of salinity, and the morphological and hydrological change in SRE results in the shift of stratification type. While the depth affects the mixing, the freshwater discharge mainly controls the straining, and the balance between mixing and straining determines the final state of the stratification in an estuarine channel. As a result, the development and location of a salt wedge along the channel in a partially mixed and highly stratified condition is also determined by the ratio of straining to mixing. Finally, our findings confirm that the contributions of mixing and straining can be assessed by using the

  20. Interaction of Structure and Physical Properties in Accretionary Wedges: Examples from the Cascadia and Nankai Trough Subduction Zones

    Science.gov (United States)

    Webb, Susanna I.

    Subduction zones are capable of producing large, megathrust earthquakes that are sometimes tsunamigenic. Structure and physical properties in the accretionary wedge play a role in how far rupture can propagate and how the wedge deforms coseismically. In this dissertation, I use seismic reflection data and velocity models from the Cascadia subduction zone and logging data from the Nankai Trough, Japan, to interpret structure, link structure to the broader wedge deformation history, and investigate the material properties at depth. I present a full structural interpretation of newly acquired seismic reflection data in the central Cascadia margin, which is characterized by dominantly landward vergent faulting in the outer wedge, a very low wedge taper angle, and a broad, lightly deformed lower slope terrace. Two decollements are active: an upper decollement within the sedimentary section, and a basal decollement at the sediment-basement interface. These interpretations help delineate the spatial extent of decollements and suggest that supra-wedge sedimentation may influence the development of the wedge, including the formation of the lower slope terrace and out of sequence fault activity. I use velocity models from central Cascadia to estimate excess pore fluid pressure and overpressure ratio at depth, which do not exceed 5 MPa and 0.15, respectively. No excess pore pressure is documented in the underthrust sediment section, but modest overpressure is likely present in the incoming sediment section and the footwalls of thrust sheets. The analysis of pore pressure shows that (1) if the base of the wedge is weak, it is due to mechanical properties of the sediments or a relatively thin underthrust layer and (2) the Cascadia wedge is relatively well-drained, and thus potentially strong, which can lead to a low wedge taper angle. In the Nankai Trough, Japan, I reprocessed sonic log data to obtain P-wave and S-wave velocity values and estimate elastic moduli. The logs